Functional analysis and cephalometric criteria

FUNCTIONAL ANALYSIS ANDFUNCTIONAL ANALYSIS AND
CEPHALOMETRIC ANALYSISCEPHALOMETRIC ANALYSIS
CRITERIA FOR FUNCTIONAL JAWCRITERIA FOR FUNCTIONAL JAW
ORTHOPAEDICSORTHOPAEDICS
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• Functional examination is of special significance inFunctional examination is of special significance in
treatment of functional appliances because of dynamictreatment of functional appliances because of dynamic
basis of therapy,basis of therapy,
• An initial functional assessment is imperativeAn initial functional assessment is imperative
• Function is ,indeed, the common denominator that joinsFunction is ,indeed, the common denominator that joins
the individual parts of the orofacial system into athe individual parts of the orofacial system into a
dynamic,integrated and purposive systemdynamic,integrated and purposive system
• Disturbance in one part of the orofacial system do notDisturbance in one part of the orofacial system do not
remain isolated but affect the equilibrium of the wholeremain isolated but affect the equilibrium of the whole
systemsystem
• This unique quality is of importance in etiologicalThis unique quality is of importance in etiological
considerations and when assessing the effectiveness andconsiderations and when assessing the effectiveness and
various side effects of different orthodontic appliancevarious side effects of different orthodontic appliance
IntroductionIntroduction

Proper treatment plan and prognosis depends on accurate diagnosis.AnyProper treatment plan and prognosis depends on accurate diagnosis.Any
abnormal function which is detected should be corrected for favourableabnormal function which is detected should be corrected for favourable
treatment outcome.treatment outcome.
Three most important aspects of orthodontic functional analysis are:Three most important aspects of orthodontic functional analysis are:
1.Examination of postural rest position and maximum intercuspation1.Examination of postural rest position and maximum intercuspation
2.Examination of the TMJ2.Examination of the TMJ
3.Examination of orofacial dysfunction3.Examination of orofacial dysfunction

Examination of the relationship : Postural restExamination of the relationship : Postural rest
position – Habitual occlusionposition – Habitual occlusion
 Determination of the postural rest positionDetermination of the postural rest position
 Registration of postural rest positionRegistration of postural rest position
 Evaluation of the relationship: Postural rest position –Evaluation of the relationship: Postural rest position –
Habitual occlusion in 3 planes of spaceHabitual occlusion in 3 planes of space
The rest position should be determined with the patient relaxedThe rest position should be determined with the patient relaxed
and sitting upright.The head is oriented by having the patientand sitting upright.The head is oriented by having the patient
look straight ahead (habitual position). If this seems toolook straight ahead (habitual position). If this seems too
variable, then the head can be positioned with the frankfurtvariable, then the head can be positioned with the frankfurt
horizontal parallel to the floor.horizontal parallel to the floor.

Determination of postural rest positionDetermination of postural rest position
 Patient’s orofacial musculature must be relaxedPatient’s orofacial musculature must be relaxed
 Muscle exercises to relax the musculature – “ TAPPING TEST”Muscle exercises to relax the musculature – “ TAPPING TEST”
 If patient is tensed – mild electric impulses to relax theIf patient is tensed – mild electric impulses to relax the
musculaturemusculature
When the mandible is in the postural resting position,itWhen the mandible is in the postural resting position,it
is usually 2-3mm below and behind the centricis usually 2-3mm below and behind the centric
occlusion,recorded in canine areaocclusion,recorded in canine area

Methods used to determine the rest position during clinicalMethods used to determine the rest position during clinical
examinationexamination
 Phonetic methodPhonetic method
 Command methodCommand method
 Non-command methodNon-command method
 Combined methodCombined method
 Phonetic methodPhonetic method::
Patient is told to pronounce certain consonants or words repeatedlyPatient is told to pronounce certain consonants or words repeatedly
(e.g.”M”,”Mississippi”).The mandible returns to the postural resting position(e.g.”M”,”Mississippi”).The mandible returns to the postural resting position
1-2 seconds after the exercise1-2 seconds after the exercise
 Command methodCommand method::
The patient is “commanded” to perform selectedThe patient is “commanded” to perform selected
functions(e.g.Swallowing),after which the mandible spontaneously returns tofunctions(e.g.Swallowing),after which the mandible spontaneously returns to
the rest positionthe rest position

Non-command method:Non-command method:
The patient is distracted,so as not to percieve which type ofThe patient is distracted,so as not to percieve which type of
examination is carried out.while being distracted, the patientexamination is carried out.while being distracted, the patient
relaxes,causing the musculature to relax as well,and the mandiblerelaxes,causing the musculature to relax as well,and the mandible
reverts to the postural rest positionreverts to the postural rest position
Combined method:Combined method:
Most suitable for functional analysis in children.the patient is firstMost suitable for functional analysis in children.the patient is first
observed during swallowing and speaking.Older children –observed during swallowing and speaking.Older children –
tapping test ,then non- command methodtapping test ,then non- command method
• Regardless of the clinical method in use, the mandible must be checkedRegardless of the clinical method in use, the mandible must be checked
extraorally to ensure that it actually has assumed the rest position-extraorally to ensure that it actually has assumed the rest position-
palpate the submental region :relaxed muscles in this area indicate thatpalpate the submental region :relaxed muscles in this area indicate that
the rest position has been attained.the rest position has been attained.
• The lips are then carefully parted with the thumb and forefinger – toThe lips are then carefully parted with the thumb and forefinger – to
observe the maxillomandibular relationshipobserve the maxillomandibular relationship

Registration of the rest positionRegistration of the rest position
Two most commonly used methodsTwo most commonly used methods
 Intra oral indirect method (using impression materials)Intra oral indirect method (using impression materials)
 Extra oral direct method (using skin reference points)Extra oral direct method (using skin reference points)
Extra oral indirect methods are the most reliableExtra oral indirect methods are the most reliable
• Roentgenocephalometric registrationRoentgenocephalometric registration
• Kinesiographic registrationKinesiographic registration

Roentgenocephalometric registrationRoentgenocephalometric registration
Two cephalograms are required, either in lateral or frontalTwo cephalograms are required, either in lateral or frontal
projection,projection,
 One radiograph in centric(habitual)occlusionOne radiograph in centric(habitual)occlusion
 One with mandible in its rest positionOne with mandible in its rest position
• The rest position and freeway space can beThe rest position and freeway space can be
determined by comparing the radiographsdetermined by comparing the radiographs

Kinesiographic registrationKinesiographic registration
Mandibular kinesiograph,according toMandibular kinesiograph,according to JankelsonJankelson, allows the mandibular, allows the mandibular
rest position to be registered 3-D.The position of mandible isrest position to be registered 3-D.The position of mandible is
recorded electronically by:recorded electronically by:
 A permanent magnet, which is fixed with rapid setting acrylic to theA permanent magnet, which is fixed with rapid setting acrylic to the
lower anterior teethlower anterior teeth
 A sensor system of six magnetometers mounted on spectacleA sensor system of six magnetometers mounted on spectacle
framesframes
Every movement of the mandible and the attached magnet out ofEvery movement of the mandible and the attached magnet out of
centric occlusion, alters the strength of the magnetic field.Thesecentric occlusion, alters the strength of the magnetic field.These
changes are recorded by the sensors , processed in the kinesiographchanges are recorded by the sensors , processed in the kinesiograph
and displayed on a storage oscilloscopeand displayed on a storage oscilloscope
The Mandibular movements and rest position are recorded two-The Mandibular movements and rest position are recorded two-
dimensionally on two preselectable levels.The electronic circuitarydimensionally on two preselectable levels.The electronic circuitary
also allows the rest position to be recorded as 3-D co-ordinatesalso allows the rest position to be recorded as 3-D co-ordinates

Evaluation of the relationship between restEvaluation of the relationship between rest
position and habitual occlusionposition and habitual occlusion
The movement of the mandible from the rest position to fullThe movement of the mandible from the rest position to full
articulation is analysed three dimensionally:sagittal , vertical andarticulation is analysed three dimensionally:sagittal , vertical and
frontal planesfrontal planes
The closing movements of the mandible can be divided into twoThe closing movements of the mandible can be divided into two
phasesphases
 Free phase:mandibular path from the postural rest to the initialFree phase:mandibular path from the postural rest to the initial
or premature contact positionor premature contact position
 Articular phase:mandibular path from the initial contact positionArticular phase:mandibular path from the initial contact position
to centric or habitual occlusion.to centric or habitual occlusion.

When closing from the rest position, the mandible may undergoWhen closing from the rest position, the mandible may undergo
both rotational and sliding movements.The objective of thisboth rotational and sliding movements.The objective of this
analysis is to determine the amount and direction of movementanalysis is to determine the amount and direction of movement
as well as the proportions of the rotational and slidingas well as the proportions of the rotational and sliding
components.components.
The following movements of the mandible from the rest position toThe following movements of the mandible from the rest position to
habitual occlusion must be differentiated for orthodontichabitual occlusion must be differentiated for orthodontic
diagnosis:diagnosis:
 Pure rotational movement (hinge movement)Pure rotational movement (hinge movement)
 Rotational movement with an anterior sliding componentRotational movement with an anterior sliding component
 Rotational movement with a posterior componentRotational movement with a posterior component

Evaluation in the sagittal planeEvaluation in the sagittal plane
When evaluating the relationship of the rest position to habitual occlusion in theWhen evaluating the relationship of the rest position to habitual occlusion in the
sagittal plane,the exceptional features of the class II and class III malocclusionssagittal plane,the exceptional features of the class II and class III malocclusions
are analysedare analysed
Class II malocclusionClass II malocclusion
According to different types of movement of the mandible from the rest positionAccording to different types of movement of the mandible from the rest position
to occlusion, the classII malocclusion can be divided into 3 typesto occlusion, the classII malocclusion can be divided into 3 types
 Rotational movement without a sliding component-the neuromuscular andRotational movement without a sliding component-the neuromuscular and
morphologic relationships correspond to each other.There is no functionalmorphologic relationships correspond to each other.There is no functional
disturbance (functional true classII)disturbance (functional true classII)

 Rotational movement with posterior slidingRotational movement with posterior sliding
movementmovement
The mandible slides backwards and isThe mandible slides backwards and is
guided into a posterior occlusalguided into a posterior occlusal
position.This finding reveals a functionalposition.This finding reveals a functional
class II malocclusion and not a true class IIclass II malocclusion and not a true class II
malrelationshipmalrelationship
 Rotational movement with anterior slidingRotational movement with anterior sliding
movement starting from the relativelymovement starting from the relatively
posterior rest positionposterior rest position
The mandible slides forwards intoThe mandible slides forwards into
habitual occlusion.The class II malocclusionhabitual occlusion.The class II malocclusion
is actually more pronounced than can beis actually more pronounced than can be
seenseen in habitual occlusionin habitual occlusion

• Treatment prognosis for functional appliance therapyTreatment prognosis for functional appliance therapy is dependentis dependent
on the analysis of the relationships and the determination of theon the analysis of the relationships and the determination of the
path of closure categorypath of closure category
• In functional class II malocclusions,the elimination of theIn functional class II malocclusions,the elimination of the
functional retrusion or protrusion leads to an improvement of thefunctional retrusion or protrusion leads to an improvement of the
sagittal relationshipsagittal relationship
• In class II malocclusions with a normal path of closure,theIn class II malocclusions with a normal path of closure,the
intermaxillary relationship must be altered,but this requires both aintermaxillary relationship must be altered,but this requires both a
morphological and a functional change to produce the desiredmorphological and a functional change to produce the desired
sagittal correctionsagittal correction
• In case of posterior displacement,combined with a projectedIn case of posterior displacement,combined with a projected
horizontal growth direction,the prognosis for class II treatment ishorizontal growth direction,the prognosis for class II treatment is
very goodvery good
• When there is an anterior displacement and a vertical growthWhen there is an anterior displacement and a vertical growth
vector,the prognosis is poorvector,the prognosis is poor

Class III MalocclusionsClass III Malocclusions
The functional relationships of class III cases determine the orthodontic treatmentThe functional relationships of class III cases determine the orthodontic treatment
possibilities and the prognosis of malocclusion.possibilities and the prognosis of malocclusion.
The closing path of the mandible from the rest position can be divided intoThe closing path of the mandible from the rest position can be divided into
three typesthree types
 Rotational movement without sliding actionRotational movement without sliding action
The anatomic/morphologic relationships correspond to the functionalThe anatomic/morphologic relationships correspond to the functional
relationship (non – functional,true class III malocclusion – unfavourablerelationship (non – functional,true class III malocclusion – unfavourable
prognosis)prognosis)

 Rotational movement with posterior sliding action.Rotational movement with posterior sliding action.
In case with pronounced mandibular prognathism,the mandible may slideIn case with pronounced mandibular prognathism,the mandible may slide
posteriorly into the position of maximum intercuspation.This masks the trueposteriorly into the position of maximum intercuspation.This masks the true
sagittal dysplasiasagittal dysplasia
Rotational movement with anterior sliding action.Rotational movement with anterior sliding action.
During the articular phase, the mandible shifts forwards and into a prognathic,During the articular phase, the mandible shifts forwards and into a prognathic,
forced bite(functional , non skeletal malocclusion , so called pseudo class III –forced bite(functional , non skeletal malocclusion , so called pseudo class III –
favourable prognosis)favourable prognosis)

True forced bite – pseudo –forced biteTrue forced bite – pseudo –forced bite
• In case of mesio occlusion an anterior sliding action is not alwaysIn case of mesio occlusion an anterior sliding action is not always
a symptom of a functional class III malocclusion.a symptom of a functional class III malocclusion.
• With this functional diagnosis, the “true forced bite”,with itsWith this functional diagnosis, the “true forced bite”,with its
favourable prognosis, and the “pseudo forced bite”, with itsfavourable prognosis, and the “pseudo forced bite”, with its
unfavourable prognosis ,must be differentiated as far asunfavourable prognosis ,must be differentiated as far as
cephalometrics is concerned.cephalometrics is concerned.
• The term “pseudo-forced bite” includes those true skeletalThe term “pseudo-forced bite” includes those true skeletal
class III malocclusions where, due to partial dentoalveolarclass III malocclusions where, due to partial dentoalveolar
compensation of the skeletal dysplasia in the anterior region,thecompensation of the skeletal dysplasia in the anterior region,the
mandible occludes at the end of the closing path by means of anmandible occludes at the end of the closing path by means of an
anterior sliding action.If one reconstructs the tipping of the anterioranterior sliding action.If one reconstructs the tipping of the anterior
teeth in a pseudo-forced bite,these cases have a pronouncedteeth in a pseudo-forced bite,these cases have a pronounced
negative overjetnegative overjet
• The dentoalveolar compensation of the skeletal dysplasia,whichThe dentoalveolar compensation of the skeletal dysplasia,which
already exists when treatment is started ,greatly restricts the rangealready exists when treatment is started ,greatly restricts the range
of orthodontic treatment possibilities and unlike a true forced bite,of orthodontic treatment possibilities and unlike a true forced bite,
is indicative of a very unfavourable prognosisis indicative of a very unfavourable prognosis

Evaluation of the relationship between rest position and habitualEvaluation of the relationship between rest position and habitual
occlusion in a vertical planeocclusion in a vertical plane
• The vertical dimension of free way space isThe vertical dimension of free way space is
assessed.This analysis is of particular importanceassessed.This analysis is of particular importance
to cases with a deep over biteto cases with a deep over bite
• The true deep overbites with a large freewayThe true deep overbites with a large freeway
space,is caused by infraocclusion of molars.thespace,is caused by infraocclusion of molars.the
prognosis for successful therapy with functionalprognosis for successful therapy with functional
methods is favourable.As the interocclusalmethods is favourable.As the interocclusal
cleerance is large, sufficient freeway space willcleerance is large, sufficient freeway space will
remain after extrusion of molarsremain after extrusion of molars
• The pseudo – deep overbite has a small freewayThe pseudo – deep overbite has a small freeway
space.The molars have erupted fully.The deepspace.The molars have erupted fully.The deep
overbite is caused by over eruption of theoverbite is caused by over eruption of the
incisors.The prognosis for elevating the biteincisors.The prognosis for elevating the bite
using functional appliances is unfavourable if theusing functional appliances is unfavourable if the
freeway space is small, extrusion of molarsfreeway space is small, extrusion of molars
adversely affects the rest position and may createadversely affects the rest position and may create
TMJ problems or cause a relapse of the deepTMJ problems or cause a relapse of the deep
overbiteoverbite www.indiandentalacademy.com

Evaluation of the relationship between rest position and habitualEvaluation of the relationship between rest position and habitual
occlusion in the transverse planeocclusion in the transverse plane
The position of midline of the mandible is observedThe position of midline of the mandible is observed
while the jaw is moved from the postural rest towhile the jaw is moved from the postural rest to
habitual occlusion.This analysis is particularlyhabitual occlusion.This analysis is particularly
relevant for the differential diagnosis of cases withrelevant for the differential diagnosis of cases with
unilateral cross bite.unilateral cross bite.
Depending on the functional analysis two types ofDepending on the functional analysis two types of
skeletal mandibular deviation can be differentiated:skeletal mandibular deviation can be differentiated:
laterognathy and laterocclusionlaterognathy and laterocclusion
LaterognathyLaterognathy: The centre of the mandible is not: The centre of the mandible is not
aligned with the facial midline in rest andaligned with the facial midline in rest and
occlusion.These dysplasia constitute trueocclusion.These dysplasia constitute true
neuromuscular or anatomical assymetry. A lateralneuromuscular or anatomical assymetry. A lateral
cross bite with laterognathy is termed true crosscross bite with laterognathy is termed true cross
bite.The prognosis is unfavourable for causalbite.The prognosis is unfavourable for causal
therapytherapy
LaterocclusionLaterocclusion:The skeletal midline shift of the:The skeletal midline shift of the
mandible can be observed only in occlusalmandible can be observed only in occlusal
position;in postural rest both midlines are wellposition;in postural rest both midlines are well
aligned.The deviation is due to toothaligned.The deviation is due to tooth
guidance(functional non-true malocclusion)guidance(functional non-true malocclusion)

Examination of the temperomandibular jointExamination of the temperomandibular joint
• Through the early elimination of functional disturbances,someThrough the early elimination of functional disturbances,some
incipient TMJ problems can be prevented or eliminated,this is anincipient TMJ problems can be prevented or eliminated,this is an
indication for early orthodontic treatment.indication for early orthodontic treatment.
• During activator therapy the condyle is diclocated to achieve aDuring activator therapy the condyle is diclocated to achieve a
remodelling of the TMJ structures and a change in muscleremodelling of the TMJ structures and a change in muscle
function.If temperomandibular structures are abnormal at thefunction.If temperomandibular structures are abnormal at the
start and hypersensitivity is a problem,the possibility ofstart and hypersensitivity is a problem,the possibility of
exacerbating the symptoms existsexacerbating the symptoms exists

Clinical examinationClinical examination
Main objective – assess the severity of the clicking, pain and dysfunction,which areMain objective – assess the severity of the clicking, pain and dysfunction,which are
characteristics of pathologic TMJ symptoms.characteristics of pathologic TMJ symptoms.
 When auscultation is carried out with the stethescope,clicking and crepitus in theWhen auscultation is carried out with the stethescope,clicking and crepitus in the
joint may be diagnosed during A-P and eccentric movements of the mandible.joint may be diagnosed during A-P and eccentric movements of the mandible.
Joint clicking is differentiated as follows:Joint clicking is differentiated as follows: initial,intermediate,terminal andinitial,intermediate,terminal and
reciprocalreciprocal clickingclicking
Initial clickingInitial clicking : retruded condyle in relation to the disc: retruded condyle in relation to the disc
Intermediate clickingIntermediate clicking : unevenness of the condylar surfaces and of the articular disc,: unevenness of the condylar surfaces and of the articular disc,
which slide over one another during the movementswhich slide over one another during the movements
Terminal clickingTerminal clicking : condyle being: condyle being movedmoved too far anteriorly, in relation to the disc,ontoo far anteriorly, in relation to the disc,on
maximum jaw openingmaximum jaw opening
Reciprocal clickingReciprocal clicking : incoordination between displacement of the condyle and the: incoordination between displacement of the condyle and the
disc,during opening and closingdisc,during opening and closing

..
 Palpation of the TMJ during opening maneuvers - possible pain on pressurePalpation of the TMJ during opening maneuvers - possible pain on pressure
of the condylar areaof the condylar area
Besides the right and left condyles can thus be checked of synchrony of action.Besides the right and left condyles can thus be checked of synchrony of action.
 Palpation of the musculature involved in the mandibular movements is aPalpation of the musculature involved in the mandibular movements is a
considerable part of examination. In cases with functional disturbances duringconsiderable part of examination. In cases with functional disturbances during
childhood only LATERAL PTERYGOID causes pain due to pressure.childhood only LATERAL PTERYGOID causes pain due to pressure.
MASSETER muscle pain is also encountered in children with TMJMASSETER muscle pain is also encountered in children with TMJ
problems.therefore, these muscle attachments should be examined on everyproblems.therefore, these muscle attachments should be examined on every
orthodontic patient .orthodontic patient .
• Initial symptom of TMJ disturbance – palpatory tenderness of musclesInitial symptom of TMJ disturbance – palpatory tenderness of muscles
• Temporalis and masseter muscles are palpated during unconsious swallowingTemporalis and masseter muscles are palpated during unconsious swallowing
b’cos this could be different from swallow on commandb’cos this could be different from swallow on command (AO 1987)(AO 1987)

Opening and closing movements of the mandibleOpening and closing movements of the mandible
 Size and direction of opening and closing are recorded during the clinicalSize and direction of opening and closing are recorded during the clinical
examinationexamination
 Deviations in speed can only be registered with electronicDeviations in speed can only be registered with electronic
device(eg.kinesiograph)device(eg.kinesiograph)
First signs of initial TMJ problems include deviations of the mandibularFirst signs of initial TMJ problems include deviations of the mandibular
opening and closing path in the sagittal and frontal planes.In patients withopening and closing path in the sagittal and frontal planes.In patients with
malocclusion and malaligned teeth,disturbances in mandibular movements aremalocclusion and malaligned teeth,disturbances in mandibular movements are
the result of an asynchronic pattern of muscle contractions.the characteristicthe result of an asynchronic pattern of muscle contractions.the characteristic
movement deviations include incongruency of the opening and closing curvesmovement deviations include incongruency of the opening and closing curves
and uncoordinated zigzag movements.the “C” and “S” types of deviation areand uncoordinated zigzag movements.the “C” and “S” types of deviation are
typical signs of funcrional disturbances.typical signs of funcrional disturbances.
Occlusal analysis – in patients with symptoms of TMJ diseaseOcclusal analysis – in patients with symptoms of TMJ disease

TMJ – Radiographic examinationTMJ – Radiographic examination
PA projections according to Ciementschitsch, RadiographsPA projections according to Ciementschitsch, Radiographs
according to schuller or Parma,Tomograms – suitable foraccording to schuller or Parma,Tomograms – suitable for
examination of the TMJexamination of the TMJ
Following findings registered :Following findings registered :
• Position of condyle in relation to fossaPosition of condyle in relation to fossa
• Width of the joint spaceWidth of the joint space
• Changes in shape and structure of the condylar head /Changes in shape and structure of the condylar head /
mandibular fossamandibular fossa

Examination of orofacial dysfunctionExamination of orofacial dysfunction
 SwallowingSwallowing
 TongueTongue
 SpeechSpeech
 LipsLips
 RespirationRespiration

SwallowingSwallowing
 Normal mature swallowing – without contracting the muscles ofNormal mature swallowing – without contracting the muscles of
facial expression.Teeth are momentarily in contact and thefacial expression.Teeth are momentarily in contact and the
tongue remains inside the mouthtongue remains inside the mouth
 Abnormal swallowing – caused by tongue thrustAbnormal swallowing – caused by tongue thrust
1.1. Protrusion of the tip of the tongueProtrusion of the tip of the tongue
2.2. No tooth contact of the molarsNo tooth contact of the molars
3.3. Contraction of the peri-oral muscles during the deglutition cycleContraction of the peri-oral muscles during the deglutition cycle
 First few years – infants swallow viscerally, with tongue betweenFirst few years – infants swallow viscerally, with tongue between
the teeth;As the deciduous dentition is completed , visceralthe teeth;As the deciduous dentition is completed , visceral
swallowing is replaced is replaced by somatic swallowingswallowing is replaced is replaced by somatic swallowing
 If visceral swallowing persist after 4 yrs of age – OrofacialIf visceral swallowing persist after 4 yrs of age – Orofacial
dysfunctiondysfunction

Examination of the tongueExamination of the tongue
 Tongue function:Tongue function:
• The object of tongue function assessment is to make differential diagnosis possible andThe object of tongue function assessment is to make differential diagnosis possible and
determine tongue’s role in malocclusiondetermine tongue’s role in malocclusion
• Functional appliance therapy is indicated if the role of the tongue malfunction is aFunctional appliance therapy is indicated if the role of the tongue malfunction is a
primary etiological factorprimary etiological factor
• A correction of basal dysplasia of skeletal parts – establishment of normal tongueA correction of basal dysplasia of skeletal parts – establishment of normal tongue
functionfunction
 Tongue postureTongue posture::
• Root is flat in mouth breathing and deep overbite caused by a small tongueRoot is flat in mouth breathing and deep overbite caused by a small tongue
• In class II div I and deep over bite,dorsum of the tongue – arched and high;tip of theIn class II div I and deep over bite,dorsum of the tongue – arched and high;tip of the
tongue – retractedtongue – retracted

Cephalometric evaluation ofCephalometric evaluation of tonguetongue postureposture
• Lateral cephalogram taken in postural rest and habitual occlusionLateral cephalogram taken in postural rest and habitual occlusion
• Changes in tongue position relate to different types of malocclusion-Changes in tongue position relate to different types of malocclusion-
class II – tip of the tongue is more retruded in rest positionclass II – tip of the tongue is more retruded in rest position
class III – tongue lies forward in rest positionclass III – tongue lies forward in rest position

Tongue thrustTongue thrust
• Important effect on etiopathogenesis of malocclusionsImportant effect on etiopathogenesis of malocclusions
1.1.Anterior tongue thrust – dysfunction during development of anterior open biteAnterior tongue thrust – dysfunction during development of anterior open bite
2.2.Lateral tongue thrust – dysfunction during development of lateral open biteLateral tongue thrust – dysfunction during development of lateral open bite
3.3.Complex tongue thrust – occlusion supported only in the molar regionComplex tongue thrust – occlusion supported only in the molar region
• The dentoalveolar anterior and posterior open bite problems - attributable toThe dentoalveolar anterior and posterior open bite problems - attributable to
abnormal tongue posture and function – responds successfully to functionalabnormal tongue posture and function – responds successfully to functional
appliance intervention in mixed dentitionappliance intervention in mixed dentition
• This is also true in cases of deep overbite,in which lateral tongue spread duringThis is also true in cases of deep overbite,in which lateral tongue spread during
posture and function has resulted in infraocclusion of posterior teethposture and function has resulted in infraocclusion of posterior teeth
• A second type of over bite – caused by supraocclusion of the incisors – smallA second type of over bite – caused by supraocclusion of the incisors – small
free way space,this type of problem is called functional pseudo overbite,infree way space,this type of problem is called functional pseudo overbite,in
these cases functional appliance is not indicatedthese cases functional appliance is not indicated
• In skeletal open bite problems,there is a genetically determined vertical growthIn skeletal open bite problems,there is a genetically determined vertical growth
pattern,often associated with marked antegonial notch – does not offer apattern,often associated with marked antegonial notch – does not offer a
favourable prognosis for orthodontic therapyfavourable prognosis for orthodontic therapy

• The consequence of tongue posture andThe consequence of tongue posture and
function abnormalities in thefunction abnormalities in the
dentoalveolar region also depends ondentoalveolar region also depends on
skeletal patternskeletal pattern
- In horizontal growth pattern , forward- In horizontal growth pattern , forward
tongue thrust – bimaxillary protrusiontongue thrust – bimaxillary protrusion
- In vertical growth pattern, the tongue- In vertical growth pattern, the tongue
thrust can open the bite,lower incisorsthrust can open the bite,lower incisors
may be tipped linguallymay be tipped lingually

Palatographic examination of the tonguePalatographic examination of the tongue
• Enables observation of tongue function during swallowing andEnables observation of tongue function during swallowing and
speaking ,evaluation of the influence of various functional orthodonticspeaking ,evaluation of the influence of various functional orthodontic
appliances on the tongueappliances on the tongue
• Direct method – byDirect method – by Oakley,Oakley,gum arabic and flour mixed and painted ongum arabic and flour mixed and painted on
the tongue,after going through the selected functional exercises,thethe tongue,after going through the selected functional exercises,the
contacts on the palate and teeth were transferred onto the castscontacts on the palate and teeth were transferred onto the casts
• Indirect method – byIndirect method – by KingsleyKingsley,blsck rubber placed on the palate and,blsck rubber placed on the palate and
tongue covered with mixture of chalk and alcoholtongue covered with mixture of chalk and alcohol
• Current direct method – superior surface of tongue covered withCurrent direct method – superior surface of tongue covered with
precise impression material;after functional exercises a polaroid print isprecise impression material;after functional exercises a polaroid print is
made of the palatal region with a surface mirror,the evaluation of themade of the palatal region with a surface mirror,the evaluation of the
palatogram is by direct measurements on the picturepalatogram is by direct measurements on the picture
• Tongue with its inherent flexibility can compensate for atypicalTongue with its inherent flexibility can compensate for atypical
morphological relationship,this compensatory potential as assessed bymorphological relationship,this compensatory potential as assessed by
palatographic record is an important diagnostic clue to establish apalatographic record is an important diagnostic clue to establish a
treatment plan and a probable prognosis for functional appliancetreatment plan and a probable prognosis for functional appliance
therapytherapy

Configuration of the craniofacial skeleton andConfiguration of the craniofacial skeleton and
dysfunctionsdysfunctions
 Horizontal growth patternHorizontal growth pattern
with tongue thrust –with tongue thrust –
bimaxillary dental protrusionbimaxillary dental protrusion
 Vertical growth pattern with tongueVertical growth pattern with tongue
thrust – lower incisors in lingualthrust – lower incisors in lingual
inclinationinclination

Methods of examinationMethods of examination
• Electronic recordingsElectronic recordings
• Electromyographic examinationElectromyographic examination
• Recording pressure exerted by tongue intraorallyRecording pressure exerted by tongue intraorally
• Roentgenocephalometric analysis – assess position and size ofRoentgenocephalometric analysis – assess position and size of
the tonguethe tongue
• Cine radiographic examinationCine radiographic examination
• Palatographic examination – records the contact surfaces of thePalatographic examination – records the contact surfaces of the
tongue with palate and teethtongue with palate and teeth
• Neurophysiologic examinationNeurophysiologic examination

Lip dysfunctionsLip dysfunctions
 Assessed in relation to configuration and functioning of the lipsAssessed in relation to configuration and functioning of the lips
Configuration of the lipsConfiguration of the lips
• Competent lips :Competent lips : lips in slight contact when musculature is relaxedlips in slight contact when musculature is relaxed
• Incompetent lipsIncompetent lips : Anatomically short lips , do not touch when: Anatomically short lips , do not touch when
musculature is relaxed.lip seal is achieved by active contraction ofmusculature is relaxed.lip seal is achieved by active contraction of
the Orbicularis oris and the Mentalis musclesthe Orbicularis oris and the Mentalis muscles
• Potentially incompetent lipsPotentially incompetent lips :The protruding upper incisors prevent:The protruding upper incisors prevent
the lip closure.otherwise the lips are developed normallythe lip closure.otherwise the lips are developed normally
• Everted lipsEverted lips : these are hypertrophied lips with redundant tissue but: these are hypertrophied lips with redundant tissue but
weak muscular tonocityweak muscular tonocity

Various methods are available for evaluating the lip profileVarious methods are available for evaluating the lip profile

Schwarz analysisSchwarz analysis
H line – corresponding to frankfort horizontalH line – corresponding to frankfort horizontal
Pn line – perpendicular to the H line at soft tissue nasionPn line – perpendicular to the H line at soft tissue nasion
Po line – perpendicular from orbitale to the H linePo line – perpendicular from orbitale to the H line
Between the two construted perpendicular lines is theBetween the two construted perpendicular lines is the Gnathic profile fieldGnathic profile field
( GPF)( GPF)

 Ricketts lip analysisRicketts lip analysis
• Reference line similar to the Schwarz TReference line similar to the Schwarz T
line,but is drawn from the tip of the nose toline,but is drawn from the tip of the nose to
soft tissue pogonionsoft tissue pogonion
• Normally,upper lip is 2-3mm and lower lip isNormally,upper lip is 2-3mm and lower lip is
1-2mm behind this line1-2mm behind this line
 Steiner lip analysisSteiner lip analysis
• Upper reference point – center of the S-Upper reference point – center of the S-
shaped curve between the tip of the nose andshaped curve between the tip of the nose and
subnasale,lower terminus – soft tissuesubnasale,lower terminus – soft tissue
pogonionpogonion
• If lip lie behind this line – they are too flat ; ifIf lip lie behind this line – they are too flat ; if
they lie in front – they are too prominentthey lie in front – they are too prominent

 Holdaway lip analysisHoldaway lip analysis
• Quantitative assessment of lip configurationQuantitative assessment of lip configuration
• H angle – angle between the tangent to theH angle – angle between the tangent to the
upper lip from soft tissue pogonion and the N-upper lip from soft tissue pogonion and the N-
B lineB line
• Ideal profileIdeal profile
A-N-B angle - 2 degreesA-N-B angle - 2 degrees
H angle – 7-8 degreesH angle – 7-8 degrees
Lower lip touching the soft tissue line thatLower lip touching the soft tissue line that
connects pogonion and the upper lip extendedconnects pogonion and the upper lip extended
to S-Nto S-N
Relative proportions of nose and upper lipRelative proportions of nose and upper lip
balancedbalanced
Tip of the nose 9mm anterior to the softTip of the nose 9mm anterior to the soft tissuetissue
lineline

Lip habitsLip habits
• Lip-suckingLip-sucking
• Lip-thrustLip-thrust
• Lip insufficiencyLip insufficiency
Any lip activity during swallowing – apart from closing the lips – isAny lip activity during swallowing – apart from closing the lips – is
unphysiologic and a symptom of an orofacial dysfunction.visualunphysiologic and a symptom of an orofacial dysfunction.visual
evidence of mentalis muscle activity is also abnormalevidence of mentalis muscle activity is also abnormal
Cheek dysfunctionsCheek dysfunctions
• In cheek – sucking or cheek – biting the soft tissues are interposedIn cheek – sucking or cheek – biting the soft tissues are interposed
between the occlusal surfaces of the teeth – formation of lateral openbetween the occlusal surfaces of the teeth – formation of lateral open
bite.bite.
• Increased lateral pressure by cheek musculature on the mandibleIncreased lateral pressure by cheek musculature on the mandible
impedes the transverse development of the jawimpedes the transverse development of the jaw
• Common in cases with buccal nonocclusionCommon in cases with buccal nonocclusion

Mouth-BreathingMouth-Breathing
• Chronically disturbed nasal respiration – restrict development ofChronically disturbed nasal respiration – restrict development of
the dentition and hinders the orthodontic treatmentthe dentition and hinders the orthodontic treatment
• Clinical findings:Clinical findings:
o High palateHigh palate
o Persisting “tooth germ position” of the upper incisorsPersisting “tooth germ position” of the upper incisors
o Narrowness of the upper archNarrowness of the upper arch
o Cross biteCross bite
o Hyperplasia of the gingivaHyperplasia of the gingiva
o Extra oral appearance – “adenoid facies”Extra oral appearance – “adenoid facies”
Hyperactivity of Mentalis muscleHyperactivity of Mentalis muscle
•Characteristic feature – deep mentolabial sulcusCharacteristic feature – deep mentolabial sulcus
•Impedes forward development of the anterior alveolar processImpedes forward development of the anterior alveolar process
in the mandiblein the mandible

Pattern of facial morphologyPattern of facial morphology
• The configuration of facial skeleton and oral respiration areThe configuration of facial skeleton and oral respiration are
correlatedcorrelated
• Proliferation of the adenoids , incidence of hypertrophiedProliferation of the adenoids , incidence of hypertrophied
tonsils – pronounced in patients with oronasal respirationtonsils – pronounced in patients with oronasal respiration
NO ADENOIDSNO ADENOIDS LARGE ADENOIDSLARGE ADENOIDSSMALL ADENOIDSSMALL ADENOIDS

Examination of breathing modeExamination of breathing mode
•The cotton pledget testThe cotton pledget test
•The mirror testThe mirror test
•Observation of the nostrilsObservation of the nostrils
The scope of functional therapy in patients with respiratory problemsThe scope of functional therapy in patients with respiratory problems
1.In habitual mouth breathing with small respiratory resistance, a1.In habitual mouth breathing with small respiratory resistance, a
functional therapy is indicated.exercises can be prescribed,holding afunctional therapy is indicated.exercises can be prescribed,holding a
sheet of cardboard between the lips is a good means of enhancing thesheet of cardboard between the lips is a good means of enhancing the
lip seallip seal
2.When there are structural problems,with excessive adenoid tissue ,2.When there are structural problems,with excessive adenoid tissue ,
allergies,orthodontics can be carried out after successful ENTallergies,orthodontics can be carried out after successful ENT
treatmenttreatment
3.If the structural conditions cannot be altered,functional appliance3.If the structural conditions cannot be altered,functional appliance
therapy cannot be instituted,in such cases , only active fixed appliancetherapy cannot be instituted,in such cases , only active fixed appliance
mechanotharapy is likely to produce the change desiredmechanotharapy is likely to produce the change desired

The significance of functional analysis in treatmentThe significance of functional analysis in treatment
planning with removable appliancesplanning with removable appliances ::
• Mandibular over closure and deep overbite with large free wayMandibular over closure and deep overbite with large free way
space – prognosis for treatment with functional appliance isspace – prognosis for treatment with functional appliance is
goodgood
• A true skeletal class III malocclusion does not offer a favourableA true skeletal class III malocclusion does not offer a favourable
prognosis for functional applianceprognosis for functional appliance
• Functional appliance therapy is particularly indicated in pseudoFunctional appliance therapy is particularly indicated in pseudo
class III malocclusions with normal tongue postureclass III malocclusions with normal tongue posture
• Functional appliance therapy is likely to be successful in casesFunctional appliance therapy is likely to be successful in cases
with primary dysfunction in open bite and an average growthwith primary dysfunction in open bite and an average growth
patternpattern

CEPHALOMETRICCEPHALOMETRIC DIAGNOSISDIAGNOSIS
FOR FUNCTIONALFOR FUNCTIONAL
APPLIANCE THERAPYAPPLIANCE THERAPY

The following information can be ascertainedThe following information can be ascertained
from the cephalometric analysisfrom the cephalometric analysis
• Configuration of the facial skeletonConfiguration of the facial skeleton
• Relationship of the jaw basesRelationship of the jaw bases
• Relationship of the axial inclination of incisorsRelationship of the axial inclination of incisors
• Assessment of the soft tissue morphologyAssessment of the soft tissue morphology
• Growth pattern and directionGrowth pattern and direction
• Localisation of the malocclusionLocalisation of the malocclusion
• Treatment possibilities and limitationsTreatment possibilities and limitations

Cephalometric reference pointsCephalometric reference points
• Reference points- located in the skeletal,dentoalveolarReference points- located in the skeletal,dentoalveolar
and soft tissue regionsand soft tissue regions
• Include anatomic , radiographic and constructed pointsInclude anatomic , radiographic and constructed points
• Constructed point not accurate – methodological errorConstructed point not accurate – methodological error
of individual point localisation accumulatesof individual point localisation accumulates

CephalometricCephalometric reference linesreference lines

Aims of interpretation of cephalometricAims of interpretation of cephalometric
measurements:measurements:
• Analysis of skeletal structure and facial typeAnalysis of skeletal structure and facial type
• Assessment of vertical and sagittal relationship betweenAssessment of vertical and sagittal relationship between
maxillary and mandibular basesmaxillary and mandibular bases
• Differentiation of skeletal and dentoalveolarDifferentiation of skeletal and dentoalveolar
malocclusionsmalocclusions
• Analysis of dental relationshipsAnalysis of dental relationships
• Analysis of soft tissue regarding etiology and prognosisAnalysis of soft tissue regarding etiology and prognosis

 The cephalometric critria can be divided into three groupsThe cephalometric critria can be divided into three groups
• 1.Analysis of facial skeleton1.Analysis of facial skeleton
• 2.Analysis of jaw bases2.Analysis of jaw bases
• 3.Analysis of the dentoalveolar relationship3.Analysis of the dentoalveolar relationship
1.Analysis of facial skeleton1.Analysis of facial skeleton
-Three angular measurements –-Three angular measurements –
saddle angle ,gonial angle and articular anglesaddle angle ,gonial angle and articular angle
-four linear measurements – anterior and posterior-four linear measurements – anterior and posterior
facial height,anterior and posterior cranial base lengthfacial height,anterior and posterior cranial base length

 The saddle angle ( N-S-Ar)The saddle angle ( N-S-Ar)
• The angle that is formed by joining the points N , S and Ar is anThe angle that is formed by joining the points N , S and Ar is an
assessment of the relationship between anterior and posterolateralassessment of the relationship between anterior and posterolateral
cranial basescranial bases
• Large saddle angle – posterior condylar position ,and mandible that isLarge saddle angle – posterior condylar position ,and mandible that is
posteriorly positioned with respect to the cranial base and the maxillaposteriorly positioned with respect to the cranial base and the maxilla
• A non compensated posterior positioning of the mandible , caused byA non compensated posterior positioning of the mandible , caused by
a large saddle angle , is very difficult to influence with functionala large saddle angle , is very difficult to influence with functional
appliance theraphyappliance theraphy
 The articular angle (S–Ar-Go)The articular angle (S–Ar-Go)
• Constructed angle that lies between the upper and lower parts of theConstructed angle that lies between the upper and lower parts of the
posterior contours of the facial skeleton.the size of this angle dependsposterior contours of the facial skeleton.the size of this angle depends
upon the position of the mandibleupon the position of the mandible
• It is large when mandible is retrognathic and small when mandible isIt is large when mandible is retrognathic and small when mandible is
prognathicprognathic
• The angle can be influenced during orthopedic theraphy,it increasesThe angle can be influenced during orthopedic theraphy,it increases
with posterior relocation of the mandible , with opening of the bite,andwith posterior relocation of the mandible , with opening of the bite,and
decreases with anterior positioning of the mandible,with closing thedecreases with anterior positioning of the mandible,with closing the
bitebite

 The Gonial angle (Ar-Go-Me)The Gonial angle (Ar-Go-Me)
• The angle formed by tangents to the body of the mandible andThe angle formed by tangents to the body of the mandible and
posterior body of the ramus – expresses the form of theposterior body of the ramus – expresses the form of the
mandible and information on its growth directionmandible and information on its growth direction
• If this angle is acute or small , the direction of growth isIf this angle is acute or small , the direction of growth is
horizontal.This is a favourable condition for anterior positioninghorizontal.This is a favourable condition for anterior positioning
of the mandible with an activatorof the mandible with an activator
• In cases with a large angle,activator treatment is contraindicated ,In cases with a large angle,activator treatment is contraindicated ,
or appliance must be constructed taking into account theor appliance must be constructed taking into account the
growth patterngrowth pattern
 Facial heightFacial height
• The posterior facial height (S-Go) and the anterior facial heightThe posterior facial height (S-Go) and the anterior facial height
(N-Me) are measured on the lateral cephalogram with the teeth(N-Me) are measured on the lateral cephalogram with the teeth
in habitual occlusionin habitual occlusion
• To estimate the direction of growth that is so important inTo estimate the direction of growth that is so important in
activator treatment, we can compare anterior and posterior facialactivator treatment, we can compare anterior and posterior facial
height and set up a ratio, according to the recommendations ofheight and set up a ratio, according to the recommendations of
Jarabak,Jarabak,
posterior facial height * 100 / anterior facial heightposterior facial height * 100 / anterior facial height
• A ratio of less than 62 % expresses a vertical growth pattern,ratioA ratio of less than 62 % expresses a vertical growth pattern,ratio
of more than 65 % - horizontal vectorof more than 65 % - horizontal vector
• The growth forecast for early mixed dentition treatment with anThe growth forecast for early mixed dentition treatment with an
activator should be carried out by comparing angular and linearactivator should be carried out by comparing angular and linear
measurements and morphological characteristics of the mandiblemeasurements and morphological characteristics of the mandible

 Anterior cranial base length (Se – N )Anterior cranial base length (Se – N )
• This measurement is made using the centre of the superior entrance to the sella turcica as aThis measurement is made using the centre of the superior entrance to the sella turcica as a
reference point , instead of sella turcica fossa outline that is usually used for cranial basereference point , instead of sella turcica fossa outline that is usually used for cranial base
establishmentestablishment
• The correlation of this criterion to the length of the jaw bases enables an assessment of theThe correlation of this criterion to the length of the jaw bases enables an assessment of the
proportional averages of these basesproportional averages of these bases
• Average length of the anterior cranial base – 68.8mm for horizontal growth patterns ,Average length of the anterior cranial base – 68.8mm for horizontal growth patterns ,
63.8mm – vertical growth vector63.8mm – vertical growth vector
 Posterior cranial base length (S – Ar)Posterior cranial base length (S – Ar)
• Short posterior cranial base – vertical growth pattern or a skeletal open bite – poorShort posterior cranial base – vertical growth pattern or a skeletal open bite – poor
prognosis for functional appliance therapyprognosis for functional appliance therapy

2.Analysis of the jaw bases2.Analysis of the jaw bases
The angles between the vertical reference lines represent the sagittal relationshipThe angles between the vertical reference lines represent the sagittal relationship
(the SNA angle and the SNB angle).The angles between the horizontal lines(the SNA angle and the SNB angle).The angles between the horizontal lines
assist in evaluating the vertical ralationship of parts (base plane angle andassist in evaluating the vertical ralationship of parts (base plane angle and
inclination angle).the linear measurements give an indication of the length ofinclination angle).the linear measurements give an indication of the length of
the maxillary and mandibular bases as well as the length of the ascending ramusthe maxillary and mandibular bases as well as the length of the ascending ramus
 SNA angleSNA angle
• Expresses the sagittal relationship of the anterior limit of the maxillary apicalExpresses the sagittal relationship of the anterior limit of the maxillary apical
base ( point A ) as related to the anterior cranial basebase ( point A ) as related to the anterior cranial base
• This angle is large in a prognathic maxilla and is small in a retruded maxillaThis angle is large in a prognathic maxilla and is small in a retruded maxilla
• When a prognathic maxilla causes class II,division I malocclusions and there isWhen a prognathic maxilla causes class II,division I malocclusions and there is
a larger than normal SNA angle, the use of activator is contraindicateda larger than normal SNA angle, the use of activator is contraindicated

 SNB angleSNB angle
• Expresses the sagittal relationship of the anterior apical base ofExpresses the sagittal relationship of the anterior apical base of
the mandibular arch and the anterior cranial basethe mandibular arch and the anterior cranial base
• Prognathic mandible – angle is large , retrognathic mandible –Prognathic mandible – angle is large , retrognathic mandible –
angle is smallangle is small
• Functional appliance treatment is indicated if the mandible isFunctional appliance treatment is indicated if the mandible is
retrognathic with a small SNB angular readingretrognathic with a small SNB angular reading
• A posteriorly located mandible can be large or small,if it is smallA posteriorly located mandible can be large or small,if it is small
the prognosis for anterior posturing in the mixed dentition isthe prognosis for anterior posturing in the mixed dentition is
good,since a larger growth increment can usually be expectedgood,since a larger growth increment can usually be expected
• Together with the favourable growth direction, the greaterTogether with the favourable growth direction, the greater
growth increments on the mandible in the horizontal patterngrowth increments on the mandible in the horizontal pattern
enables successful treatment of these cases by anterior posturingenables successful treatment of these cases by anterior posturing
of the mandible in functional appliance therapyof the mandible in functional appliance therapy
 Basal plane angle ( Pal – MP )Basal plane angle ( Pal – MP )
• Expresses the angle between the maxillary and mandibular jawExpresses the angle between the maxillary and mandibular jaw
bases and used to determine the inclination of mandibular planebases and used to determine the inclination of mandibular plane
itselfitself
• In the horizontal growth pattern thisIn the horizontal growth pattern this angle is small, whereas it isangle is small, whereas it is
large in vertical growth grouplarge in vertical growth group www.indiandentalacademy.com

 Inclination angleInclination angle
• Gives an assessment of the inclination of theGives an assessment of the inclination of the
maxillary basemaxillary base
• It is the angle formed by the Pn line and the palatalIt is the angle formed by the Pn line and the palatal
planeplane
• A large angle expresses upward and forwardA large angle expresses upward and forward
inclination, whereas a small angle indicates ainclination, whereas a small angle indicates a
downward and backward tipping of the anterior enddownward and backward tipping of the anterior end
of the palatalof the palatal plane or maxillary baseplane or maxillary base

 Rotation of the jaw basesRotation of the jaw bases
• Basal plane angle and inclination angle are used to evaluate the rotation of theBasal plane angle and inclination angle are used to evaluate the rotation of the
upper and lower jaw basesupper and lower jaw bases
• These rotations are of special interest in treatment with functional appliancesThese rotations are of special interest in treatment with functional appliances
because they show whether such appliances are indicated and provide criteriabecause they show whether such appliances are indicated and provide criteria
for appliance constructionfor appliance construction
Bjork differentiates the two processes involved in the rotational growth of theBjork differentiates the two processes involved in the rotational growth of the
mandiblemandible
1.remodelling of the mandible in the symphyseal and Gonial areas –1.remodelling of the mandible in the symphyseal and Gonial areas – intermatrixintermatrix
rotation.rotation.
Apposition in the gonial area, resorption in the symphyseal area- horizontalApposition in the gonial area, resorption in the symphyseal area- horizontal
rotationrotation
Apposition in the symphyseal area , resorption in the gonial area – verticalApposition in the symphyseal area , resorption in the gonial area – vertical
rotationrotation
2.vertical or horizontal rotation of the mandible in its neuromuscular envelope –2.vertical or horizontal rotation of the mandible in its neuromuscular envelope –
matrix rotation.matrix rotation.
rotation observed cephalometrically is called total rotation,it consists of bothrotation observed cephalometrically is called total rotation,it consists of both
intermatrix and matrix rotationintermatrix and matrix rotation
• Functional orthodontic and orthopedic methods alter the function and guide theFunctional orthodontic and orthopedic methods alter the function and guide the
growth process,rotation of the mandible may be moderately influencedgrowth process,rotation of the mandible may be moderately influenced
therapeuticallytherapeutically

Rotation of the Maxillary baseRotation of the Maxillary base
• The Inclination angle records the rotation of the maxillary base to the anterior cranial baseThe Inclination angle records the rotation of the maxillary base to the anterior cranial base
• The angle is not measured directly,but defined as the angle between the Pn-perpendicularThe angle is not measured directly,but defined as the angle between the Pn-perpendicular
and the palatal planeand the palatal plane
• Anteinclination-forward maxillary rotationAnteinclination-forward maxillary rotation
retroinclination-backward maxillary rotationretroinclination-backward maxillary rotation
• Maxillary inclination influences the clinical appearance of the anterior tooth position,it canMaxillary inclination influences the clinical appearance of the anterior tooth position,it can
be changed by dentofacial orthopedic treatment.be changed by dentofacial orthopedic treatment.
NORMALINCLINATION = 85NORMALINCLINATION = 85
ANTELNCLINATION > 85ANTELNCLINATION > 85
RETROINCLINATION < 85RETROINCLINATION < 85
Combinations of maxillary and mandibular rotationCombinations of maxillary and mandibular rotation
•Convergent rotation of the jaw basesConvergent rotation of the jaw bases
•Divergent rotation of the jaw basesDivergent rotation of the jaw bases
•Upward rotation of both jaw basesUpward rotation of both jaw bases
•Downward rotation of both jaw basesDownward rotation of both jaw bases

Rotation of the jaw basesRotation of the jaw bases
Convergent and Divergent rotationConvergent and Divergent rotation
Rotation in the same directionRotation in the same direction
•Combination of the maxillary andCombination of the maxillary and
mandibular rotation determines themandibular rotation determines the
degree of the anterior overbitedegree of the anterior overbite
•When the jaw bases are rotatedWhen the jaw bases are rotated
equivalently in the same direction,theequivalently in the same direction,the
vertical dimension during growthvertical dimension during growth
remains constantremains constant
•Convergent rotation – deep biteConvergent rotation – deep bite
• Divergent rotation – open biteDivergent rotation – open bite

Linear measurement of the jaw basesLinear measurement of the jaw bases
• In the determination of indication for functionalIn the determination of indication for functional
appliance therapy,both the position and the length ofappliance therapy,both the position and the length of
the jaw bases must be assessedthe jaw bases must be assessed
• The length of the maxillary and mandibular bases andThe length of the maxillary and mandibular bases and
ascending ramus is measured relative to Se-Nascending ramus is measured relative to Se-N
• The ideal dimension relative to Se-N is calculated usingThe ideal dimension relative to Se-N is calculated using
the following ratiosthe following ratios
N-Se : Man base - 20 : 21N-Se : Man base - 20 : 21
Ascending ramus : Man base – 5: 7Ascending ramus : Man base – 5: 7
Max base : Man base – 2 : 3Max base : Man base – 2 : 3
 Extent of the mandibular baseExtent of the mandibular base
• Determined by measuring the distance Gonion –Determined by measuring the distance Gonion –
PogonionPogonion
• Ideally the mandibular base should be 3mm longerIdeally the mandibular base should be 3mm longer
than Se-Nthan Se-N

 Extent of the maxillary baseExtent of the maxillary base
• Distance between the posterior nasal spine andDistance between the posterior nasal spine and
point A projected perpendicularly onto thepoint A projected perpendicularly onto the
palatal planepalatal plane
• The evaluation of this dimension has two “ideal”The evaluation of this dimension has two “ideal”
measurements : one related to N-Se and themeasurements : one related to N-Se and the
other to the length of the mandibular baseother to the length of the mandibular base
 Length of the ascending ramusLength of the ascending ramus
• Distance between Gonion and CondylionDistance between Gonion and Condylion
• Important in determination of posterior facialImportant in determination of posterior facial
height and subsequent relation to the anteriorheight and subsequent relation to the anterior
facial heightfacial height

Evaluation of the length of the jaw baseEvaluation of the length of the jaw base
 Mandibular baseMandibular base
• If the length of the mandibular base corresponds to the distance N-Se,it indicates an ageIf the length of the mandibular base corresponds to the distance N-Se,it indicates an age
related normal mandibular length and an average growth increment can be expectedrelated normal mandibular length and an average growth increment can be expected
• If the base is shorter,growth increment is larger;if the base is longer,growth increment isIf the base is shorter,growth increment is larger;if the base is longer,growth increment is
smallersmaller
• A retrognathic mandible may have either short or long baseA retrognathic mandible may have either short or long base
• If base is short the cause of retrognathism is a growth deficiency;if a favourable growthIf base is short the cause of retrognathism is a growth deficiency;if a favourable growth
direction is present ,the prognosis for functional appliance therapy is gooddirection is present ,the prognosis for functional appliance therapy is good
• A mandibular base that is both long and retrognathic can result from two possibilitiesA mandibular base that is both long and retrognathic can result from two possibilities
11.The mandible is in a functionally retruded position because of over closure and occlusal.The mandible is in a functionally retruded position because of over closure and occlusal
guidance.in postural rest,it is anterior to habitual occlusion.treatment is simple – eliminationguidance.in postural rest,it is anterior to habitual occlusion.treatment is simple – elimination
of the forced guidance and up and back path of closure in either the mixed or permanentof the forced guidance and up and back path of closure in either the mixed or permanent
dentitiondentition
22.The mandible is morphogenetically “built” into the facial skeleton in a posterior position.the.The mandible is morphogenetically “built” into the facial skeleton in a posterior position.the
temporal fossa is posterior and superior.This discrepancy is not compensated despite the longtemporal fossa is posterior and superior.This discrepancy is not compensated despite the long
mandibular base.the prognosis for functional appliance therapy in these cases is poormandibular base.the prognosis for functional appliance therapy in these cases is poor

 Maxillary baseMaxillary base
• Assessment of length of maxillary base has 2 ideal values : one related to the distance N-Se,theAssessment of length of maxillary base has 2 ideal values : one related to the distance N-Se,the
other to the length of the mandibular baseother to the length of the mandibular base
• A deviation from the mandibular base-related norm --- maxillary base is too long or too shortA deviation from the mandibular base-related norm --- maxillary base is too long or too short
• If the maxillary base corresponds to the mandibular base - related norm,the facial skeleton isIf the maxillary base corresponds to the mandibular base - related norm,the facial skeleton is
proportionally developed,particularly if the ramal length also corresponds to these valuesproportionally developed,particularly if the ramal length also corresponds to these values
• If the N-Se length does not relate to these three proportionate measurements,the facialIf the N-Se length does not relate to these three proportionate measurements,the facial
skeleton is proportionate but either too large or too smallskeleton is proportionate but either too large or too small
 Ascending ramusAscending ramus
• If the ramus is too short in relation to the other proportions,a large amount of growth can beIf the ramus is too short in relation to the other proportions,a large amount of growth can be
expected because the growth pattern is not verticalexpected because the growth pattern is not vertical
• In vertical growth patterns the ramus remains shortIn vertical growth patterns the ramus remains short

 Morphology of the mandibleMorphology of the mandible
• Orthognathic type of face – ramus and body of theOrthognathic type of face – ramus and body of the
mandible are fully developed,width of the ascendingmandible are fully developed,width of the ascending
ramus is equal to the height of the body of theramus is equal to the height of the body of the
mandible,including the height of the alveolar processmandible,including the height of the alveolar process
and incisors.the condylar and coronoid processesand incisors.the condylar and coronoid processes
almost on the same plane,and the symphysis is wellalmost on the same plane,and the symphysis is well
developeddeveloped
• In the prognathic type the corpus is well developed andIn the prognathic type the corpus is well developed and
wide in the molar region.The symphysis is wider in thewide in the molar region.The symphysis is wider in the
sagittal plane.the ramus is wide and long ,and gonialsagittal plane.the ramus is wide and long ,and gonial
angle is acute or smallangle is acute or small
• Retrognathic facial type the corpus isRetrognathic facial type the corpus is
narrow,particularly in the molar region.the symphysis isnarrow,particularly in the molar region.the symphysis is
narrow and short,coronoid process is shorter than thenarrow and short,coronoid process is shorter than the
condylar process,and the gonial angle is obtuse or largecondylar process,and the gonial angle is obtuse or large
• The prognathic type of mandible growsThe prognathic type of mandible grows
horizontally.even if an average or slightly verticalhorizontally.even if an average or slightly vertical
growth direction is evident in the mixedgrowth direction is evident in the mixed
dentition,shifting of the mandible to a horizontaldentition,shifting of the mandible to a horizontal
growth direction can be expectd in the following yearsgrowth direction can be expectd in the following years
• In a retrognathic mandible,shifting of the growthIn a retrognathic mandible,shifting of the growth
pattern in the opposite direction is less likely andpattern in the opposite direction is less likely and
produces much less expressivityproduces much less expressivity

•Analysis of dentoalveolar relationshipAnalysis of dentoalveolar relationship
 Axial inclination of incisorsAxial inclination of incisors
 Position of the incisorsPosition of the incisors
 Axial inclination of the incisorsAxial inclination of the incisors
 Upper incisorsUpper incisors
• The long axis of the maxillary incisors is extendedThe long axis of the maxillary incisors is extended
to intersect the S-N line,and the posterior angle isto intersect the S-N line,and the posterior angle is
measuredmeasured
• Larger angles indicate a procumbency or labialLarger angles indicate a procumbency or labial
crown tippingcrown tipping
• Incisor protrusion requires lingual tipping,aIncisor protrusion requires lingual tipping,a
therapeutic objective that can be achieved withtherapeutic objective that can be achieved with
removable appliances if adequate space is availableremovable appliances if adequate space is available

 Lower incisorsLower incisors
• To assess axial inclination of the teeth – measurement of the posterior angle betweenTo assess axial inclination of the teeth – measurement of the posterior angle between
the long axis of the lower incisors and the mandibular planethe long axis of the lower incisors and the mandibular plane
• Ideal angle – 90 degreesIdeal angle – 90 degrees
• Smaller angle – lingual tipping of the incisors – advantages for functional applianceSmaller angle – lingual tipping of the incisors – advantages for functional appliance
treatmenttreatment
• Classical activators are most effective in the sagittal plane and tend to tip the lowerClassical activators are most effective in the sagittal plane and tend to tip the lower
incisors labiallyincisors labially
• If lower incisors are already labially tipped , functional appliance treatment is moreIf lower incisors are already labially tipped , functional appliance treatment is more
difficult;anterior repositioning of the mandible and uprighting of the lower incisorsdifficult;anterior repositioning of the mandible and uprighting of the lower incisors
become necessary,if possible moved in the opposite directionbecome necessary,if possible moved in the opposite direction
• This requires special appliance design in the lower anterior segmentThis requires special appliance design in the lower anterior segment

 Position of the incisorsPosition of the incisors
• Linear measurements are the best assessors of theLinear measurements are the best assessors of the
position of the incisors with respect to the profileposition of the incisors with respect to the profile
• Common method – to measure the distance ofCommon method – to measure the distance of
the incisal edges to the N-Pog line – Facial linethe incisal edges to the N-Pog line – Facial line
• Average position of the maxillary incisors is 2 to 4Average position of the maxillary incisors is 2 to 4
mm anterior to the N-Pog line.the lower incisorsmm anterior to the N-Pog line.the lower incisors
vary from 2mm posterior to 2mm anterior to thisvary from 2mm posterior to 2mm anterior to this
lineline
• The relationship of the lower incisors to the N-The relationship of the lower incisors to the N-
Pog line also helps determine the sagittalPog line also helps determine the sagittal
discrepancydiscrepancy
• Incisors behind this line can be moved labiallyIncisors behind this line can be moved labially
because space is available,incisors anterior to thebecause space is available,incisors anterior to the
facial plane that must be moved lingually requirefacial plane that must be moved lingually require
additional space,which may be obtained only byadditional space,which may be obtained only by
extraction proceduresextraction procedures
• The amount and direction of growth spurt shouldThe amount and direction of growth spurt should
be considered in the mixed dentition,while idealbe considered in the mixed dentition,while ideal
position of incisors is being plannedposition of incisors is being plannedwww.indiandentalacademy.com

Anteroposterior skeletal assessmentAnteroposterior skeletal assessment
o The AP position of the jaws is assessed based on measurements that use the trueThe AP position of the jaws is assessed based on measurements that use the true
horizontal (TH) as the reference linehorizontal (TH) as the reference line
 Size of the mandible (Go-Gn) relative to the anterior cranial base (SNa)Size of the mandible (Go-Gn) relative to the anterior cranial base (SNa)
• A ratio of GoGn:SN=1 indicates a well balanced mandibular body relative to theA ratio of GoGn:SN=1 indicates a well balanced mandibular body relative to the
cranial base.cranial base.
• The importance of this measurement lies in the fact that a very retrognathic profileThe importance of this measurement lies in the fact that a very retrognathic profile
may be due to a short mandibular body that affects the anteroposterior plane , whichmay be due to a short mandibular body that affects the anteroposterior plane , which
may require surgical intervention, depending on the deformity and age of the patientmay require surgical intervention, depending on the deformity and age of the patient
 Maxillomandibular ratio (PNS-ANS:ArGnMaxillomandibular ratio (PNS-ANS:ArGn))
• According to Michigan growth atlas, the length of the mandible,defined fromAccording to Michigan growth atlas, the length of the mandible,defined from
Articulare(Ar) to Gnathion(Gn), is almost exactly double of the maxillaryArticulare(Ar) to Gnathion(Gn), is almost exactly double of the maxillary
length,defined from posterior and anterior nasal spine(PNS-ANS)length,defined from posterior and anterior nasal spine(PNS-ANS)
• A ratio of 1:2 indicates the actual lengths of the maxilla and mandible are in goodA ratio of 1:2 indicates the actual lengths of the maxilla and mandible are in good
balance with each other.balance with each other.

 Assessment of the position of the jaws using LinearAssessment of the position of the jaws using Linear
and Angular Measurementsand Angular Measurements
• Proffit and White have proposed using a perpendicular from theProffit and White have proposed using a perpendicular from the
nasion with the TH in assessing the maxillary and mandibularnasion with the TH in assessing the maxillary and mandibular
anteroposterior relationship with linear measurements.anteroposterior relationship with linear measurements.
• 3 suggested linear measurement from points A,B,and pogonion (Pg)3 suggested linear measurement from points A,B,and pogonion (Pg)
to nasion perpendicular to TH relate the position of the maxilla,to nasion perpendicular to TH relate the position of the maxilla,
mandible ,and chin respectivelymandible ,and chin respectively
• A- point should be 1 mm in front of the Na – perpendicular,A- point should be 1 mm in front of the Na – perpendicular,
whereas B- point and Pg should be 3mm and 1mm behind the linewhereas B- point and Pg should be 3mm and 1mm behind the line
respectivelyrespectively
• Due to the importance of accurate assessment of the anteroposteriorDue to the importance of accurate assessment of the anteroposterior
position of both the maxilla and the mandible relative to each otherposition of both the maxilla and the mandible relative to each other
and the cranial base,angular measurements are also calculatedand the cranial base,angular measurements are also calculated
between the –between the –
-TH and NaA – 90 degrees +/-3degrees-TH and NaA – 90 degrees +/-3degrees
-TH and NaB – 87 degrees-TH and NaB – 87 degrees
-TH and NaP – 89 degrees +/- 3 degrees-TH and NaP – 89 degrees +/- 3 degrees

Assessment of the relative anteroposterior position of the maxilla and theAssessment of the relative anteroposterior position of the maxilla and the
mandible – the true horizontal Wits and the ANB anglemandible – the true horizontal Wits and the ANB angle
• If A and B are projected on the TH through perpendicular lines pointsIf A and B are projected on the TH through perpendicular lines points
A and B are defined,respectivelyA and B are defined,respectively
• The AB distance is defined as the true horizontal Wits versus theThe AB distance is defined as the true horizontal Wits versus the
original Wits on the occlusal planeoriginal Wits on the occlusal plane
• The TH Wits provides a better and more clear relationship of theThe TH Wits provides a better and more clear relationship of the
anteroposterior position of the jaws relative to each other than doesanteroposterior position of the jaws relative to each other than does
the original Wits ,which can sometimes be affected by the inclinationthe original Wits ,which can sometimes be affected by the inclination
of the occlusal plane or by the inclination of the Frankfort horizontalof the occlusal plane or by the inclination of the Frankfort horizontal
• The Wits appraisal does not necessarily focus attention on changesThe Wits appraisal does not necessarily focus attention on changes
actually occuring in the sagittal relation between the maxilla and theactually occuring in the sagittal relation between the maxilla and the
mandiblemandible
• Rather,because of changes in the angulation of the occlusal plane,theRather,because of changes in the angulation of the occlusal plane,the
true sagittal changes are likely to be disguisedtrue sagittal changes are likely to be disguised
• A correlation between angle ANB and Wits would not be expectedA correlation between angle ANB and Wits would not be expected
because they each involve an exclusive point or plane , which is notbecause they each involve an exclusive point or plane , which is not
necessarily biologically related.the mean +/- SD for this measurementnecessarily biologically related.the mean +/- SD for this measurement
is 4 +/-2 mmis 4 +/-2 mm
• In addition to the TH Wits linear measurement, an angularIn addition to the TH Wits linear measurement, an angular
measurement ,the ANB angle , is also used to assess themeasurement ,the ANB angle , is also used to assess the
anteroposterior position of the jawsanteroposterior position of the jaws
The mean+/- SD is 3 degrees +/- 2 degreesThe mean+/- SD is 3 degrees +/- 2 degrees

Anteroposterior assessment of the chin – theAnteroposterior assessment of the chin – the
chin length and the BNP anglechin length and the BNP angle
•A line parallel to the TH is drawn tangent to theA line parallel to the TH is drawn tangent to the
mandible at Menton.projections of the B point and Pgmandible at Menton.projections of the B point and Pg
define the chin length(BP)define the chin length(BP)
•The mean +/- SD for this measurement is 2 +/- 2mmThe mean +/- SD for this measurement is 2 +/- 2mm
•An angular measurement , the BNP angle , assesses theAn angular measurement , the BNP angle , assesses the
prominence of the chin relative to the body of theprominence of the chin relative to the body of the
mandiblemandible
•The mean +/-SD for the BNP angle is -2 degrees +/- 2The mean +/-SD for the BNP angle is -2 degrees +/- 2
degreesdegrees

Vertical skeletal assessmentVertical skeletal assessment
The following 10 cephalometric measurements may aid the clinicianThe following 10 cephalometric measurements may aid the clinician
in appreciating a patient’s facial vertical growth:in appreciating a patient’s facial vertical growth:
 Width of the symphysis parallel to the True Horizontal fromWidth of the symphysis parallel to the True Horizontal from
Pogonion (P TH)Pogonion (P TH)
• The greater this measurement is ,the more of forward rotation is to be expectedThe greater this measurement is ,the more of forward rotation is to be expected
• A narrow symphysis corresponds to a backward growth rotationA narrow symphysis corresponds to a backward growth rotation
• The mean +/- SD is 16.5mm +/- 3mmThe mean +/- SD is 16.5mm +/- 3mm
 Angle of the symphysis ( BP – MeTH )Angle of the symphysis ( BP – MeTH )
• This is defined by the line connecting B-point and Pogonion (P) as it crosses a line parallel to theThis is defined by the line connecting B-point and Pogonion (P) as it crosses a line parallel to the
true horizontal (TH) at Menton (Me)true horizontal (TH) at Menton (Me)
• The mean +/- SD is 75 degrees +/- 5 degreesThe mean +/- SD is 75 degrees +/- 5 degrees
• If the symphysis is inclined backwards , that is , if the angle of the symphysis is acute , this is anIf the symphysis is inclined backwards , that is , if the angle of the symphysis is acute , this is an
indication of forward rotational patternindication of forward rotational pattern
• If it is inclined forward (angle is obtuse),there will be backward rotationIf it is inclined forward (angle is obtuse),there will be backward rotation

 Mandibular plane angle (GoMe–THMandibular plane angle (GoMe–TH))
• One of the most widely used cephalometric measurements , this angle may sometimes maskOne of the most widely used cephalometric measurements , this angle may sometimes mask
the true growth tendencies of the mandible due to extensive remodelling changes occuring atthe true growth tendencies of the mandible due to extensive remodelling changes occuring at
the angle of the mandible and the symphysisthe angle of the mandible and the symphysis
• High values indicate a backward growth rotator,and low ones indicate a horizontal growthHigh values indicate a backward growth rotator,and low ones indicate a horizontal growth
patternpattern
• The mean +/- SD is 27 degrees +/-5 degrees.the angle will decrease approximately 2 degreesThe mean +/- SD is 27 degrees +/-5 degrees.the angle will decrease approximately 2 degrees
+/- 2 degrees from childhood to adulthood.+/- 2 degrees from childhood to adulthood.
 Sum of posterior anglesSum of posterior angles
• The mean value of the sum of the cranial flexure angle SNa – SAr (saddle angle),Articular anglThe mean value of the sum of the cranial flexure angle SNa – SAr (saddle angle),Articular angl
(SAr – ArGo) and gonial angle (ArGo-GoMe) is 396 degrees +/- 4 degrees(SAr – ArGo) and gonial angle (ArGo-GoMe) is 396 degrees +/- 4 degrees
• High values indicate a vertical growth pattern (clockwise,opening or backwardHigh values indicate a vertical growth pattern (clockwise,opening or backward
rotation),whereas low ones show a horizontal growth pattern (counter clockwise,closing orrotation),whereas low ones show a horizontal growth pattern (counter clockwise,closing or
forward growth rotation)forward growth rotation)
• The mean +/-SD of the individual angles is:The mean +/-SD of the individual angles is:
SNa – SAr – 123 +/-5 degreesSNa – SAr – 123 +/-5 degrees
SAr - ArGo – 143 degrees +/- 6 degreesSAr - ArGo – 143 degrees +/- 6 degrees
ArGo – GoMe – 130 degrees +/- 7 degreesArGo – GoMe – 130 degrees +/- 7 degrees
 Gonial angle (ArGoMe)Gonial angle (ArGoMe)
• Described by Bjork and Jarabak and Fizell , with a mean ofDescribed by Bjork and Jarabak and Fizell , with a mean of
130 degrees +/-7 degrees , an increased gonial angle130 degrees +/-7 degrees , an increased gonial angle
indicates a backward growth rotator, and a decreasedindicates a backward growth rotator, and a decreased
one indicates a forward growth rotatorone indicates a forward growth rotator

• Gonial angle ratioGonial angle ratio
• A line from Gonion to Nasion divides the gonial angle into upper (ArGoNa) and lowerA line from Gonion to Nasion divides the gonial angle into upper (ArGoNa) and lower
(NaGoMe).(NaGoMe).
• If the ratio of the upper to the lower angle is more than 75% (high upper angle ) –If the ratio of the upper to the lower angle is more than 75% (high upper angle ) –
indicates increased horizontal growth rotationindicates increased horizontal growth rotation
• The opposite – high lower angle indicates a vertical growth patternThe opposite – high lower angle indicates a vertical growth pattern
• Posterior cranial base to Ramus height ratio (SAr :ArGo)Posterior cranial base to Ramus height ratio (SAr :ArGo)
• The length of the posterior cranial base needs to be measured and compared to the meanThe length of the posterior cranial base needs to be measured and compared to the mean
for the individual sex and the age groupfor the individual sex and the age group
• Providing that the length of Ar is within normal limits , a ratio value of more than 75 %Providing that the length of Ar is within normal limits , a ratio value of more than 75 %
would indicate a short ramus height,thus contributing to a clockwise rotation skeletalwould indicate a short ramus height,thus contributing to a clockwise rotation skeletal
patternpattern
• A short posterior cranial base is also indicative of a backward growth rotatorA short posterior cranial base is also indicative of a backward growth rotator
• Posterior / Anterior face height ratio ( SGo : NaMe )Posterior / Anterior face height ratio ( SGo : NaMe )
• Values higher than 65% - forward growth pattern ,Values higher than 65% - forward growth pattern ,
ratio of less than 65% - backward growth rotatorratio of less than 65% - backward growth rotator

JOURNAL REVIEWJOURNAL REVIEW

Eight methods of analysing a cephalogram to establishEight methods of analysing a cephalogram to establish
the A-P skeletal discrepancy – BJO 1981 vol 8the A-P skeletal discrepancy – BJO 1981 vol 8
• Downs analysisDowns analysis
• Steiner analysisSteiner analysis
• Eastman analysisEastman analysis
• Bjork analysisBjork analysis
• Ricketts analysisRicketts analysis
• Tweed analysisTweed analysis
• Wits analysisWits analysis
• Wylie analysisWylie analysis

Eight methods of analysing a cephalogram toEight methods of analysing a cephalogram to
establish A-P skeletal discrepancyestablish A-P skeletal discrepancy
The 8 analyses use between them three occlusal planesThe 8 analyses use between them three occlusal planes
1.A line joining the midpoint of the overlap of the mesio-buccal cusps of the1.A line joining the midpoint of the overlap of the mesio-buccal cusps of the
upper and lower first molars with the point bisecting the overbite of theupper and lower first molars with the point bisecting the overbite of the
incisors.this is used byincisors.this is used by DownsDowns andand SteinerSteiner
2.The functional occlusal plane - A line joining the midpoint of the overlap of the2.The functional occlusal plane - A line joining the midpoint of the overlap of the
mesio-buccal cusps of the first molars and the buccal cusp of the pre molarsmesio-buccal cusps of the first molars and the buccal cusp of the pre molars
or deciduous molarsor deciduous molars
3. A line joining the mid section of the molar cusps with the tip of the upper3. A line joining the mid section of the molar cusps with the tip of the upper
incisor, used byincisor, used by BjorkBjork
Three mandibular planes are usedThree mandibular planes are used
1.The tangent to the lower most border of the mandible, used by1.The tangent to the lower most border of the mandible, used by TweedTweed andand
RickettsRicketts
2.2.The line joining the Gonion and Menton used byThe line joining the Gonion and Menton used by DownsDowns andand EastmanEastman analysisanalysis
3.The line joining the Gonion and Gnathion,used by3.The line joining the Gonion and Gnathion,used by SteinerSteiner

A new approach of assessing SagittalA new approach of assessing Sagittal
discrepancies : The beta anglediscrepancies : The beta angle
• A new angle – beta angle – developed as aA new angle – beta angle – developed as a
diagnostic aid to evaluate sagittal jawdiagnostic aid to evaluate sagittal jaw
relationshiprelationship
• 3 skeletal landmarks – point A , point B ,3 skeletal landmarks – point A , point B ,
and apparent axis of the condyleand apparent axis of the condyle
• 3 lines –3 lines –
line connecting centre of condyle C withline connecting centre of condyle C with
BB
line connecting A and B pointsline connecting A and B points
line from point A perpendicular to the C-line from point A perpendicular to the C-
B lineB line
• Beta angle – angle between the lastBeta angle – angle between the last
perpendicular to the C-B lineperpendicular to the C-B linewww.indiandentalacademy.com

• Beta angleBeta angle
between 27degrees-35 degrees - class I skeletal patternbetween 27degrees-35 degrees - class I skeletal pattern
less than 27 degrees – class IIless than 27 degrees – class II
greater than 34 degrees – class IIIgreater than 34 degrees – class III
• Beta angle enriches the current cephalometric tools availableBeta angle enriches the current cephalometric tools available
to the clinician and enables better diagnosis and treatmentto the clinician and enables better diagnosis and treatment
planning for the patientsplanning for the patients

Summary :Summary :
-salient points of cephalometric analysis for the use of functional-salient points of cephalometric analysis for the use of functional
appliance therapyappliance therapy
• Allows anomalies to be located and differentiations made betweenAllows anomalies to be located and differentiations made between
skeletal and dentoalveolar malocclusionsskeletal and dentoalveolar malocclusions
• Helps determine primary and secondary dysplastic structures andHelps determine primary and secondary dysplastic structures and
possible autonomous compensatory responses before treatmentpossible autonomous compensatory responses before treatment
beginsbegins
• Allows the determination of whether the jaw bases are anteriorly orAllows the determination of whether the jaw bases are anteriorly or
posteriorly positioned , short or longposteriorly positioned , short or long
• In the vertical plane the possible rotations of the maxillary andIn the vertical plane the possible rotations of the maxillary and
mandibular bases can be observed and the growth patternmandibular bases can be observed and the growth pattern
delineateddelineated
• Assessment of the influences of neuromuscular dysfunction on theAssessment of the influences of neuromuscular dysfunction on the
dentition – vital for diagnosis and treatment planning withdentition – vital for diagnosis and treatment planning with
functional appliancefunctional appliance

References :References :
• Petrovic – Dentofacial orthopedics with functionalPetrovic – Dentofacial orthopedics with functional
applianceappliance
• Graber and Neumann – Removable orthodonticGraber and Neumann – Removable orthodontic
appliancesappliances
• Rakosi and Jonas – Orthodontic diagnosisRakosi and Jonas – Orthodontic diagnosis
• Alexander Jacobson – Radiographic cephalometryAlexander Jacobson – Radiographic cephalometry
• Thomas Rakosi – Cephalometric RadiographyThomas Rakosi – Cephalometric Radiography
• Chong Yol Baik – AJO July 2004Chong Yol Baik – AJO July 2004
• Moira Brown – BJO Vol 8 , 1981Moira Brown – BJO Vol 8 , 1981
• D.Millett and J.F.Gravely – BJO 1991D.Millett and J.F.Gravely – BJO 1991

THANK YOUTHANK YOU

Functional analysis and cephalometric criteria

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