Ab jr ts cosmetic /certified fixed orthodontic courses by Indian dental academy

ARRANGEMENT OF ARTIFICIAL
TEETH IN ABNORMAL
JAW RELATIONS

INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com


TEETH SETTING IN ABNORMAL
JAW RELATIONS

♦ TEETH SETTING IS A COMBINATION OF

ART AND SCIENCE AND IS ONE OF THE
MOST ABUSED SECTIONS OF
PROSTHETIC DENTISTRY.

♦ USUALLY IT DOES NOT TAKE MUCH

EFFORT TO DO A REASONABLY
ACCEPTABLE SETUP FOR A NORMAL
JAW RELATION-BUT WHEN
ABNORMAL JAW RELATIONS OCCURTHEY POSE A PROBLEM IN MODIFYING
NORMAL GUIDELINES TO FULFILL ALL
DEMANDS www.indiandentalacademy.com

RIDGE RELATIONSHIPS
NORMAL RIDGE RELATIONSHIP



Upper Ridge in the anterior region
is slightly labial to the lower ridge


CONTD….

 The interalveolar crest line between
the two ridges in the posterior region
forms an 80 degree angle to a
horizontal plane(i.e crest of lower
ridge slightly buccal to that of upper

ABNORMAL RIDGE
RELATIONSHIP
♦ Any deviation in the anterior or

posterior region from the normal
ridge relationship is considered
abnormal


Abnormal relation if :
Upper ridge is located much
further anteriorly than the lower ridge, i.e.,
( Maxillary Prognathism)

Upper ridge is located in the
same line as (or) lingual to the lower ridge,i.e.,
( Mandibular Prognathism)



♦ In the Posterior region;

abnormal relation if:

Crest of lower ridge is placed lingual
to that of upper ridge ,i.e.,
(wider upper arch)

when crest of lower ridge is placed
further bucally to that of the upper arch,i.e.,
(wider lower arch)

TEETH SETTING IN NORMAL RIDGE
RELATION-SYNOPSIS OF STEPS INVOLVED
♦ 1)MOUNTING CASTS AFTER JAW

RELATION RECORD ONTO ARTICULATOR
♦ 2)ESTABLISHING GUIDE LINES
♦ 3)ARRANGING MAXILLARY ANTERIOR
TEETH
♦ 4)ARRANGING MANDIBULAR ANTERIOR
TEETH
♦ 5)ARRANGING MANDIBULAR POSTERIOR
TEETH
♦ 6)ARRANGING MAXILLARY POSTERIOR
TEETH
♦ 7)BALANCING THE OCCLUSION

ARRANGEMENT OF TEETH
PRINCIPAL FACTORS
TO BE CONSIDERED
♦ 1.POSITION OF THE ARCH
♦ 2.CONTOUR OF THE ARCH
♦ 3.ORIENTATION OF THE PLANE
♦ 4.INCLINATION FOR ARTICULATION
♦ 5.POSITIONING FOR ESTHETICS


POSITION OF THE ARCH
♦ a) Former anteroposterior position of the natural

teeth
♦ b) Esthetics(lip fullness and relation of orbicularis
oris to its attaching muscles)
♦ c) Relation and form of the ridges
♦ d) Phonetics
♦ e) Fullness of the ridge
♦ f ) Height of the ridge
♦ g ) Surgical preparation of the mouth

ARCH FORM
♦ A ) Anterior arch form

1)Contour of the face
2)Relation of the opposing arch
3)Contour of the edentulous arch
a)Square
b)Tapering
c)Ovoid

ARCH FORM - Contd…
♦ Posterior Arch Width

1) Bucco lingual position in relation to
the opposing ridge ( to be in harmony
between lines of force of two ridges)
a)Prognathous ridge relation
b)Cross-bite A ridge relation
c)Cross-bite B ridge relation
2) Orthognathous ridge relation
3) Buccolingual contour of the ridge
4) Tongue shape and size

ORIENTATION OF THE
PLANE
♦ A)Inclination of the posterior teeth to harmonize

with the condylar and incisal inclination to form
compensating curves
♦ B)Anterior vertical position for esthetics
♦ C)Favorable division of the intermaxillary space
♦ D)Relative size of bearing area of the mandible
and maxilla
♦ E)Inclination of the plane to prevent shunting of
the denture
♦ F)Height of the ridges

INDIVIDUAL TOOTH
POSITIONS FOR ARTICULATION
♦ A)Condylar Inclination
♦ B)Incisal guide inclination(overbite and

overjet)
♦ C)Compensating curve
♦ D)Inclination of the cusps
♦ E)Orientation of the plane


POSITIONING FOR ESTHETICS
♦ A)Normal positions
♦ B)Variations for harmony

1)Balanced opposing lines
2)Harmony with types of profiles
3)Harmony with lateral lines of the
face
a)Square
b)Tapering
c)Ovoid
d)Combination of square,tapering and
ovoid

ANTEROPOSTERIOR POSITION
OF THE ARCH
♦ Factors governing:
♦ 1.Consideration of the orbicularis oris and its

attaching muscles(means positioning and
expression of lips)-teeth should be positioned in a
way that this muscle is not thrown backwards
which will render them ineffective whiling
contracting

♦ 2.Ridge resorption and its influence in

2. Ridge resorption and its influence in
anteroposterior position of arch

♦ Ridge resorption process in the

maxillary arch occurs in a upward and
backward direction-therefore crest of
ridge is more posterior in a resorbed
ridge than in a fresh ridge

RIDGE RESORPTION-CONTD…..
♦ Teeth are therefore placed too far lingual for the

correct facial expression and the function of the
facial muscles around the mouth
♦ If teeth are set over the ridge(as per rules of teeth
setting)-artificial senile appearance results
♦ Moreover positioning of teeth in their former
position does not create an unfavorable
leverage-’coz,a reduction in incisal angle is
permissible and advisable-which aids in
functional occlusion
♦ (hence both function and esthetics are obtained)

RIDGE RESORPTION-CONTD…..
♦ Ridge resorption in the lower arch is

more straight and downwards and
hence in this case,teeth are usually
placed over the ridge


POSTERIOR ARCH WIDTH –
INFLUENCE ON ARRANGEMENT
OF TEETH
♦ Posterior arch width is governed by a line

drawn between the crests of the two ridges
in any abnormal jaw relation
♦ Difference in the method of ridge resorption
in both arches leads to many ridge relations
which are abnormal and require a setting of
teeth in cross-bite relations in order to
obtain maximum efficiency of dentures

POSTERIOR ARCH WIDTH
CONTD…..
1

2

♦ PROGNATHIC RELATIONSHIP
♦ 1.Anterior and posterior teeth of the

maxilla are set to the lingual instead to the
buccal of the mandibular teeth throughout

CROSS-BITE “A” RELATION

♦ Relation normal in the anterior region

and prognathic in the posterior region


CROSS-BITE “B” RELATION

♦ Relation- Normal in the posterior areas.

Prognathic in the anterior anterior
part

ORTHOGNATHIC RIDGE
RELATION

♦ Relation-Retrusion of the lower anterior

teeth with the posterior teeth in normal
relation to each other

ORIENTATION OF THE PLANE
♦ Height of the occlusal plane is influenced

by various factors in the anterior and
posterior region of arch
(for ex,anteriorly-lip length,ridge fullness
influence etc influence the anterior plane)
(for ex,posteriorly-intermaxillary space
,ridge height and fullness influence the
posterior plane)


ORIENTATION OF PLANE-CONTD
♦ In any case balance must be obtained in

various levels of plane orelse a unfavorable
leverage may result b’coz of poorly divided
intermaxillary space
♦ Favorable positioning of plane should be

established and then harmony in balance
attempted at that position

ORIENTATION OF PLANE-CONTD
♦ Inclination of plane – important factor in

denture stability
♦
1)Plane too low in anterior region,too
high in posterior region-maxillary denture
shunting forward may occur
♦
2)Plane too high in anterior
region,too lowin posterior regionmandibular denture shunting forward may
occur

ESTABLISHING GUIDE LINES
MAXILLARY CAST
♦ 1)Line 1 (A):

designates anterior
margin of the incisal
papilla – valuable aid
for positioning the
maxillary central
incisors.


CONTD……..
♦2)Line

2:designates midline and indicates
division between the right and the left
quadrants.
♦3)Line 3:designates the posterior

margin of the eminences when the canine
eminences are visible on cast and
coincides with the posterior surface of
canines

ESTABLISHING GUIDE LINES
Contd…….

♦ MANDIBULAR CAST
♦ Line 1:Bisecting the curve of the arch aids in

positioning the mandibular central incisors.the
curve of arch is used for positioning the central
incisors and the canines.

MANDIBULAR GUIDE LINES
CONTD……
♦ Line 2:Canine points are the approx.. points that

designate the distal surface of the mandibular
canine

♦ Line 3:The line following the crest of the residual

ridge from the canine point to the retromolar pad
aids in positioning the posterior teeth

♦ Line 4:bisects the vertical height of the

retromolar pad and aids in establishing the
vertical position of the occlusal surfaces of
posterior teeth www.indiandentalacademy.com

ANTERIOR TEETH SETTING
CONSIDERATIONS
♦

1)Anteroposterior positioning
♦
2)Anterior slope
♦
3)Mesiodistal inclination
♦
4)Inferosuperior positioning in relation
to a horizontal plane
♦
5)Rotation on long axis


ARRANGEMENT OF UPPER
ANTERIOR TEETH
LABIO-LINGUAL INCLINATIONS
♦ Central incisors♦ Set to harmonize with

patients profile
according to labial
surface of the wax
occlusion rim
established during jaw
relation registration


LABIOLINGUAL INCLINATION
CONTD…….
♦ Lateral incisors-

Inclination more than
that of the central
incisor.
♦ Placed slightly lingual to
and above level of
incisal plane.

CONTD…….

♦ Canines
♦ Inclination is almost

perpendicular to and
the incisal edge
contacts the lower wax
rim


MESIO-DISTAL INCLINATION OF
UPPER ANTERIOR TEETH

♦ 1)SQUARE FORM
♦
1)Central incisor is nearly perpendicular
♦
2)Lateral incisor inclined more distally
♦ at the cervical end than the central
♦
3)Canine is inclined more distally than
♦ any other anterior teeth(provides more
♦ vigorousness of personality)

CONTD…….

♦ OVOID FORM TEETH:
♦

1)Central incisor inclined approximately 2
degrees distally at the cervical end
♦
2)Lateral incisor is inclined ,more than the
central
♦
3)Canine is inclined more than the lateral
incisor approx… 6 degrees at cervical end to
provide softness of appearance

CONTD…….

♦ TAPERING FORM TEETH:
♦
1)Central incisor is inclined approximately 3

degrees at the cervical end
♦
2)Lateral incisor is inclined more than the
central incisor
♦
3)Canine is more inclined than the lateral
incisor approximately 6 degrees at cervical end to
provide delicacy to the personality

FORM OF RESIDUAL RIDGE AND
ANTERIOR TEETH SETTING
SQUARE ARCH FORM:

Distance between canines are wider
Posterior ridge are more parallel than others
Curvature of anterior ridge are mild

CONTD… TEETH SETTING IN
SQUARE ARCH ….
Sense of individuality given by changing the
alignment of teeth
♦ 1)Distal end of the central incisors rotate toward
the edge
♦ 2)Edge of lateral incisors are perpendicular to
the midline.
♦ 3)Distal end of canines rotate toward the line of
posterior arch form
♦ ARRANGEMENT PROVIDES-PERSPECTIVE

AND VIGOR TO ANTERIOR SETUP

CONTD…….
♦ OVOID ARCH FORM

♦

♦

Distance between canines are narrower and
the curvature of anterior ridge is more severe than
the upper arch.

CONTD.. - TEETH SETTING IN
OVOID ARCH FORM
1)Edges of central incisor are
perpendicular to midline
2)Lateral incisor follows to the arch line
3)Distal end of canine follows towards
the line of posterior ridge
ARRANGEMENT PROVIDES
SOFTNESS IN APPEARANCE

CONTD…….
♦ TAPERING ARCH FORM

♦ 1)Distance of canines is narrower
♦ 2)Curvature of anterior arch is more severe than

others


CONTD……
♦ TEETH SETTING
♦

1)Distal ends of central incisors should be
rotated lingually.
♦ 2)Lateral incisors follow to arch line
♦ 3)Distal end of canine is set up to posterior
ridge
♦ ARRANGEMENT EXPRESSES DELICACY


ARRANGEMENT OF
MANDIBULAR ANTERIOR TEETH

♦ Central Incisors - properly inclined labially
♦ Lateral Incisors - Perpendicularly
♦ Canines
- Properly inclined lingually

CONTD……
(MESIODISTAL INCLINATIONS)

1)Central incisors - Perpendicularly
♦ 2)Lateral Incisors - Perpendicularly or
♦
slightly inclined mesially
♦ 3)Canines
- Properly inclined mesially

POSTERIOR TEETH
ARRANGEMENT
♦ The arrangement - should position them in

relation to their 3 possible dimensions( as close
as practical to their original or natural,position) this placement makes it
♦
1) for patient easy to adapt to dentures
♦
2)permits the tongue and cheeks to function
♦
effectively during speech, mastication
♦
and deglutition and
♦
3)esthetically more acceptable

REASONS FOR SETTING
LOWER TEETH FIRST







Setting of upper posterior teeth first - makes
it necessary to make many adjustments
Lower ridge offers more reliable landmarks
Lower denture more difficult denture to
stabilize
Lower denture offers less support than the upper
More critical limitations to the positioning of the
lower teeth
If the lowers are set first ,they seldom need
to be altered www.indiandentalacademy.com

MANDIBULAR TEETH SETTING
Contd………
♦ Mandibular 1st molar setting
♦
1)Compensating curve – start with the first

molar.
♦
2)Mesial cusps are on the plane established by
the anterior teeth and the bicuspids.
♦
3)Distal cusps of the 1st molar are raised about
0.5mm above this plane.
♦
4)Buccal and Lingual cusps are set at the
same height to make the transverse plane
horizontal.
♦
5)Central Fossa is aligned with the canine
-retromolar padwww.indiandentalacademy.com
reference line

MANDIBULAR MOLAR SETTING
Contd………
♦ Mandibular Second Molar setting
♦

1)Second molar continues the
cuspal elevation of the compensating curve.
♦
2)Buccal and Lingual cusps are
horizontal
♦
3)Central fossa is aligned with the
canine – retromolar pad reference points.


♦ Mandibular premolar setting
♦
Teeth manipulated into position so that
the occlusal height matches the plane
established by the mandibular anterior
teeth.
♦
Buccal and Lingual cusps are
horizontal and are made to touch the
maxillary occlusal rim
♦
The central fossae should be in line
with anteroposterior reference line

Contd……..
♦ Final Considerations
♦

1)Alignment and cuspal heights must
be symmetric on both sides.
♦
2)Marginal ridges of adjacent teeth
should be at same height to present a
smooth transition from side to side.


MAXILLARY POSTERIOR TEETH SETTING
♦ PREREQUISITES
♦ Incisal guide pin set and checked for proper

occlusal vertical dimension
♦ Incisal guide pin adjusted to provide for anterior
clearance in lateral and protrusive excursions
♦ Lateral inclination of incisal guidance should
never be steeper than the bucco-lingual inclination
of modified anatomic teeth
♦ Incisal guide inclination –never be steeper than
inclination of the condylar path
♦ Shallower incisal guidance makes obtaining
balanced occlusion easier

GRINDING MAXILLARY
POSTERIOR TEETH
♦ MODIFICATIONS BEFORE SETTING

1)All transverse ridges eliminated that
would cause mesiodistal interlocking and
interferences
2)Maxillary lingual cusps blunted,shaped
and smoothened-to fit into common central fossa
of lowers.
3)Buccal cusps of anatomic teeth
progressively shortened by grinding from 1st
premolar to 2nd molar(gives buccal cusp clearance
in CO and during lateral movements.

MAXILLARY TEETH SETTING
GENERAL CONSIDERATIONS
♦ 1.SET THEM FOR PROPER CUSP

POSITION AND STATIC CUSP
CONTACT IN “CR”
♦ 2.CHECK AND REFINE DYNAMIC
CUSP CONTACT IN
WORKING,BALANCING AND
PROTRUSIVE MOVEMENTS

MAXILLARY FIRST MOLAR
SETTING AND ARTICULATING
(CENTRIC OCCLUSION)

♦

1)Ridge of the mesio-buccal cusp
of upper first molar rests in the anterior
buccal groove of the lower first molar
♦
2)Distal inclined plane of upper
first molar touches the mesio-buccal cusp of
the lower second molar

CONTD (CENTRIC OCCLUSION)
♦ 3)Mesio-lingual cusp of the upper first

molar fits squarely into the central fossa of
the lower first molar.
♦

4)Disto-lingual cusp of the upper
first molar touches the mesial ridge of the
lower second molar


WORKING SIDE CONTACTS

1)Buccal cusps of the upper first molar
contact buccal cusps of lower first molar and
mesial slope of lower second molar.
2)Mesiolingual cusp contacts ridges formed
by protrusive and retrusive lingual planes of
lower first molar.
3)Distal slope of the upper distolingual cusp
touches the mesial slope of the lower second
molar

BALANCING SIDE CONTACTS

♦

1)Mesiolingual cusp of upper first molar
slides through the distobuccal groove of the lower
first molar
♦
2)Distolingual cusp of the upper first
molar contacts the mesiobuccal cusp of the lower
second molar

MAXILLARY 2ND PREMOLAR
(CENTRIC OCCLUSION)

1) Tip of the buccal cusp of the upper second
premolar contacts the mesiobuccal ridge of the
buccal cusp of the lower first molar and the
distobuccal ridge of the lower second premolar
2)Lingual cusp of upper second premolar is at
the embrasure between the lower first molar and
the lower second premolar.

3)Distal ridge contacts the mesiolingual
cusp of the lower first molar
4)Mesial ridge contacts the distal slope of
the lower second premolar


(WORKING SIDE CONTACTS)

♦

1)Distobuccal slope of the upper 2nd
premolar contacts the mesiobuccal slope of the
lower 1st molar.
♦
2)Mesiobuccal slope of the upper 2nd
premolar contacts the distobuccal slope of the
lower 2nd premolar
♦
3)Lingual cusp of the upper 2nd premolar
closes the embrasure formed by the lower 1st
molar and lower 2nd premolar

BALANCING SIDE CONTACTS

♦

1)Lingual cusp of the the
upper second premolar contacts the
mesiobuccal cusp of the lower first
molar

MAXILLARY SECOND MOLAR
(CENTRIC OCCLUSION)

1)The ridge of the mesiobuccal of the upper second
molar rests in the buccal groove of the lower second
molar.
2)The mesiolingual cusp of the upper second molar
fits squarely into the central fossa of the lower
second molar

MAXILLARY 2ND MOLAR
CONTD(CENTRIC OCCLUSION)

2) The mesiolingual cusp of the upper second
molar fits squarely into the central fossa of the
lower second molar



1)The buccal cusps of the lower second molar are
in contact with the buccal cusps of the upper
second molar and with the distal slopes of the upper
first molar.

CONTD
2)The mesiolingual cusp of the upper second
molar is in contact with the ridges formed by the
protrusive and retrusive lingual planes of the lower
second premolar.
3)The mesiolingual slope of the lower second
molar touches the distolingual cusp of the upper
first molar.


(BALANCING SIDE CONTACTS)

1)The mesiolingual cusp of the upper second
molar slides through the distobuccal groove of the
lower second molar.
2)The distolingual cusp of the upper first molar
contacts the mesiobuccal cusp protrusive plane
of the lower second molar

MAXILLARY 1ST PREMOLAR
(CENTRIC OCCLUSION)

♦ 1)Tip of buccal cusp of upper 1st

premolar contacts the distobuccal ridge
of the lower first premolar and the
mesiobuccal ridge of the lower second
premolar. www.indiandentalacademy.com

♦ 2)the lingual cusp of the upper first

premolar is at the embrasure between the
lower first and second premolars.
♦ 3)The mesial ridge of the upper first
premolar contacts the distal slope of the
lower first premolar.
♦ 4)The distal ridge of the contacts the mesial
slope of the lower second premolar.


♦ 1) The disto buccal slope of the upper first

premolar contacts the mesiobuccal slope of
the lower second premolar.
♦ 2)The mesiobuccal slope of the upper first
premolar contacts the distobuccal slope of
the lower first premolar.

MAXILLARY FIRST PREMOLAR
CONTD….
♦ 3)The lingual cusp of the upper first

premolar closes the embrasure formed by
the lower first and second premolars


(BALANCING SIDE CONTACTS)

♦ 1)The lingual cusp of the upper first

premolar contacts the buccal cusp of the
lower second premolar

COMPLETED SETUP

After obtaining a proper static cusp
contact(CO) in CR ,balancing of the
occlusion is then carried out

TEETH SETTING IN ABNORMAL JAW
RELATIONS

????
♦ Upper-lower ridge

relationship is an individual
problem for each complete
dentutr patient

♦ ABNORMAL RIDGE

RELATIONS – NEED TO
MODIFY NORMAL
GUIDELINES
NECESSARY TO
FULFILL ALL
DEMANDS

CLASS II JAW RELATIONS


MAXILLARY PROTRUSION
PROBLEMS FACED &
ARRANGEMENT OF TEETH
1)INCREASED OVERJET
Leads to Abnormal upper and lower canine tooth
relationship-no attempt to reduce it by moving upper
teeth palatally or lower teeth labially
2)DISCREPANCY IN CANINE RELATIONSHIP
Normally distal surface of canine tooth –(located
at) tip of the cusp of upper canine,whereas in
Max.prognathism it leads to the lower canine
tooth finishing anywhere from the tip to distal surface
of upper canine &
Excessive prognathism leads to distal incline of
cusp of lower canine posterior to distal surface of
upper canine tooth

PROBLEMS FACED IN CLASS-II
JAW RELATIONS-CONTD……
2)DISCREPANCY IN CANINE
RELATIONSHIP
Normally distal surface of canine tooth –
(located at) tip of the cusp of upper
canine,whereas in
Max.prognathism it leads to the lower
canine tooth finishing anywhere from the tip to
distal surface of upper canine &
Excessive prognathism leads to distal
incline of cusp of lower canine posterior to
distal surface of upper canine tooth

CLASS-II RIDGE RELATION
ARRANGEMENT OF POSTERIOR TEETH

♦ IF, Discrepancy is slight

Upper teeth moved slightly pallataly –
To provide working occlusal contact
with the lower teeth{limited application}


CLASS – II RIDGE RELATION
POSTERIOR TEETH ARRANGEMENT
Contd……
MUCH WIDER UPPER ARCH
Method 1:
a)Lower posterior teeth are correctly placed
on crest of the ridge
b)Upper teeth are then set so that they
occlude well with the lower teeth
c)Buccal contours-Wax built up
d)Wax replaced by Tooth colored
acrylic resin
(ESTHETIC AND CHEEK SUPPORT FULFILLED

Method 2
♦ 1)Upper Posterior teeth first arranged-esthetic

demands met
♦ 2)Lower teeth kept on crest of ridge
♦ 3)Unfavorable occlusal relationship results
♦ 4)to obtain functional oclusal contact-wax is
added on the palatal aspect of upper posteriors
♦ 5)Wax-replaced by tooth colored resin

♦ (FUNCTIONALLY EFFECTIVE,OCCLUSAL

CONTACT OBTAINED + ESTHETIC
BUCCAL SURFACE CONTOUR OF UPPER
TEETH OBTAINED)

SETTING UPPER POSTERIOR
TEETH IN CLASS-II RELATION
♦ UPPER FIRST PREMOLAR SETTING
♦

1)Flattened lingual cusp occludes with
flattened buccal cusp of lower first premolar

♦

2)Large buccal horizontal overlap
occurs in first bicuspid area when teeth are
set to proper arch form.


CONTD……..
♦ UPPER SECOND PREMOLAR SETTING
♦ 1)Upper 2nd premolar is set with its flattened

lingual cusp occluding with the flattened buccal
cusp of the lower second premolar
♦ 2)There is less buccal overlap and a larger area of

contact is possible between this teeth


SETTING UPPER MOLARS
♦ 1)The upper molars are set with their

lingual cusp in the modified central fossa of
the lower teeth.
♦ Contacts are checked for deflective inclines

and if found are grinded .


EVALUATION OF
COMPLETED SETUP
♦ 1)Posteriors should have a centric occlusion with

stable nondeflective stops.

♦ 2)Only lingual cusps are the occluding elements

on the upper teeth-They contact the flattened
buccal cusps of the lower premolars and the
central fosa of the lower molars.

♦ 3)After the primary requirement (STABLE
♦ CENTRIC OCCLUSION) is obtained,balancing

of occlusion is carried out


ARRANGEMENT OF TEETH IN
CLASS-III JAW RELATIONS
♦ PROBLEMS ASSOCIATED WITH

CLASS-III RELATIONS
♦
Condition is characterized by the
lower anterior ridge being forward in
relation to maxillary ridge
♦
1)may vary from edge to edge relation
♦
or
♦
2)marked prognathism

MANAGEMENT OF
PROBLEMS ASSOCIATED WITH
CLASS III RELATIONS

♦ 1)Ridges are edge to edge-then incisal

edges of upper and lower incisors and
cuspids also meet in edge to edge


♦ Upper and lower teeth are placed
♦

as near as possible to the labial plates
of bone in their respective ridges
♦
(normal horizontal overlap should not
be attempted when ridge relation does not
permit-if done then stability of denture will
be greatly hampered.).
♦ edge to edge relation enhances stability

♦ EXTREME PROTRUSION OF THE

MANDIBLE
♦
1)Negative or reverse horizontal overlap
should be used.(magnitude depends on degree of
protrusion )
♦ Other associated problems
♦ Wider lower arch-leads to problems in selecting

size of teeth(I.e both arch teeth cannot be selected
from the same mold)

♦ Other associated problems
♦ Wider lower arch-leads to problems in selecting

size of teeth(i.e both arch teeth cannot be selected
from the same mold);if done so then spaces
between lower anterior teeth will occur and
esthetics will be reduced


♦ Solutions
♦ 1.if reverse horizontal overlap is negligible,then

spacing will not be very obvious.
♦ 2.in gross cases
♦
a.use slightly larger lower tooth mold for the
lowers
♦
b.use slight overlapping in the uper anterior
teeth(if esthetically acceptable)-automatically
narrows lower arch space and eliminates spacing
♦
c.use an extra lower incisor to avoid spaces(least acceptable-’coz some amount of spacing
should be present for the already prominent arch)

♦ Canine relationship in CLASS III cases:
♦

Relationship –does not pose much of a
problem
♦
Distal surface of lower canine coincides
with the tip of the upper canine
♦
If it finishes mesial to the canine tip,the
discrepancy can be rectified using small spaces
between the lower anterior teeth so that the canine
will have normal relation

ARRANGEMENT OF POSTERIOR
TEETH IN CLASS III CASES
♦ PROBLEMS FACED
♦

1.Crest of lower arch is located further
buccally than that part of the upper residual
ridge.(vary little to marked)-Leads to
problem of developing an adequate occlusal
relationship between upper and lower teeth


♦ SOLUTIONS
♦

1.Difference in size is slight and upper
posterior ridge is well formed:

♦

Upper posterior teeth can be et
slightly buccal to the crest of the ridge ,a
position that correctly placed lower teeth
can make an effective occlusal contact with
antagonists…

♦ 2.Non-Anatomic teeth may be used
♦

a.allows more fredom in buccolingual
placement
♦
b. still provides adequate occlusal
contact between upper snd lower teeth.
♦
c.Teeth can stil be kept on the crests
of the respective ridges without losing
desired occlusal contacts.

♦ LOWER ARCH IS TO WIDE:
♦

1.Interchange using upper teeth on
the lower denture and lower teeth on the
upper denture.
♦
2.Interchange is made across the arch
as well.(for ex.. Right upper teeth are
placed on left lower ridge,left lower teeth
are placed on right upper arch ….)

♦ A.First lower teeth are placed on upper

ridge.
♦ B.First premolar is eliminated from upper
arch to develop correct intercuspal
relationship.
♦ C.Second premolar,first molar and second
molar(lower teeth) are set on upper ridge
♦ D.once upper teeth are set on the lower arch
they are made to set against the lower teeth
on the upper arch

♦ D)once upper teeth are set on the lower arch

they are made to set against the lower teeth
on the upper arch
♦
a.Mesiobuccal cusp of (now)lower
molar(I.e upper molar’s) fits into buccal
groove of (now) upper first molar (lower
molar) thus maintaining the anatomic
relations of theteeth,though inverted.
♦
b.other teeth are set in usual manner

♦ Results of such a arrangement
♦ 1.buccal cusps of the lower first and second

molar overlap the upper teeth-I.e reverse
buccal overlap is set.
♦ 2/however In premolar region this
horizontal overlap is eliminated by setting
thelower teeth such that their buccal cusps
are between inclines of the buccal cusps of
upper teeth(necessary b’coz lower residual
ridgeis narrowwr in molar region

SEQUENTIAL STEPS OF
ARRANGING TEETH IN
CLASS III JAW RELATIONS
♦ 1.Setting lower posterior teeth
♦

Same criteria is used as that used in
setting teeth in normal ridge relationship
♦ 2.Grinding modifications for lower teeth
♦
No variations are made in grinding
procedures in the initial
modification.additional spot grinding will
be necessary when upper posteriors are set.

Grinding modifications for upper
posterior teeth

1.each tooth is modified before
setting
2.all transverse ridges are eliminated
to eliminate mesiodistal interlocking


Special individual tooth grinding
1.depends on the tooth that initiates
the crossing over of the occlusion-when
this occurs upper tooth is flattened on
both buccal and lingual cusps to
establish a stable centric occlusion
2.Teeth in crossbite relation need
additional modification by grinding on
the upper buccal cusps-(roundening )

SETTING UPPER POSTERIOR
(CLASS III)
1

2

3

♦ 1-UPPER FIRST PREMOLAR

Usually set to a typical anatomic
relationship-this is anterior to crossbite
relationship

CONTD…..
2-UPPER SECOND PREMOLAR
Usually the transition tooth where the crossover
starts.
Upper buccal and lingual cusps are flattened.

♦

Lower teeth are also flattened on their
buccal and lingual cusps
♦ Upper and lower premolars are set buccalto -buccal and lingual -to –lingual

♦ 3-UPPER MOLAR TEETH

1.Set in a cros-bite relation(with rounde
upper buccal cusps in lower central fossa)
After complete checking balancing of
occlusion is done


SUMMARY
♦ ARRANGEMENT OF TEETH IS AN ART

BASED UPON BIOMECHANICAL FACTORS
GOVERNING THE ULTIMATE SUCCES OF
DENTURES.
♦ AN UNDERSTANDING OF THE INTERPLAY

OF THE FACTORS IS THEREFORE
NECESSARY TO THE WHOLE PROCEDURE
OF TEETH SETTING


♦ THUS TO DEVELOPA WORKABLE

ARRANGEMENT ,NECESSARY
CHANGES SHOULD BE INTRODUCED
WHENEVER NECESSARY,WHICH
ALONE WILL COPE UP WITH THE
VARIOUS JAW ABNORMALITIES
FACED IN EVERYDAY CLINICAL
PRACTICE


THANK YOU
Leader in continuing dental education


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