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

www.indiandentalacademy...
INTRODUCTION




The achievement of a stable,
functional and esthetic arch form has
long been one of the prime
objective...




Various authors have used different
curved mathemetical models,but
stability of these arch forms has not
been establ...
DEFINITION


ARCH FORM-position and relationship the
teeth have
with each other
in all 3 dimensions

www.indiandentalacad...
-It is the collective response of all
teeth to all of the environment forces
and their resultant positions in the
oral cav...


-dental arch form is made up of
teeth which assumes unique
positions along a compound curve
representing an equilibrium...
DETERMINATION OF
ARCH FORM


Determined by
-skeletal pattern
-muscular forces
“ neutral zone”
( Mills 1968)

www.indiande...
TYPES OF ARCH FORM
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BONWILL
HAWLEY
ELLIPSE
PARABOLA
CHUCKS –ARCH FORM
CANTENARY CURVE
BRADER...
BONWILL


In 1885, he noted the tripod
shape of the lower jaw and
declared that it formed an
equilateral triangle with th...


He stated that this triangle
existed for the proper
functioning of the teeth.
Importantly, he noted that the
bicuspids ...
HAWLEY




In 1905, Hawley employed some of
Bonwill’s principles in proposing a
geometric method for constructing
the id...




It was proposed that the
bicuspids and molars should be
aligned along these extended
straight lines.
Hawley did, how...




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Arch form is constant for all
induviduals
The radius of the arch varied
depending on the size of the anterior
tee...
CONSTRUCTION

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PARABOLA
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Angle , 1907, - Defined “line of
occlusion”, as being “the line
with which, in form and position
according to ...
PARABOLA
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By E.H.Angle in 1906

Fits as well as any ideal arch
Ignors narrowing of arch form over the
second molars

www...
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

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In describing the First order bends,
Angle objected particularly to the
straight line proposed from cuspid to
third ...
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Landmarks
A,D,D’,E,E’

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GRAY


In 1942, Gray’s Anatomy stated :

“The maxillary dental arch forms
an elliptical curve...The
mandibular dental arc...
CHUCK
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Chuck -In 1934, noted the variation in
human arch form and pointed out that
arch forms had been referred to as...
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Chuck superimposed this arch form on
a millimeter grid and used this
template for archwire construction
according to...
DRAWBACKS OF PARABOLAELLIPSE ARCH FORM




MacConaill -1949, stated that, in
considering the line of occlusion, it
would...
BLACK


In 1902, he stated that the upper
teeth are arranged in a semiellipse and that the lower teeth
were arranged simi...
CATENARY CURVE

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Mcconnail and scher -1949
He stated that the catenary
curve, fit so many cases with
exactness that it ...




Shape formed by a length of chain
held at each end and allowed to drop
Catenary curve could be described as
a centra...
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



Ignores narrowing of archform over
the second molar
The length of the chain and the
distance between the supports
de...
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Catenary curve fits the dental arch
form of the premolar-canine-incisor
segment of a arch very nicely for
most indiv...
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Catenary curve a better
representation of mandibular dental
arch
Ellipse or parabola represents
maxillary arch (N...


In 1957, Scott also supported the
concept of the catenary curve as
the shape of the human arch
based on the development...


He pointed out that the basal
bone of the maxilla and mandible
remains much more constant in
form in all mammals and fo...


Burdi and Lillie in 1966 stated
that the basic bony arch is
established as early as 9.5 weeks
in utero and that this fo...


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Musich, in 1973, supported the
concept of the catenary curve as the
ideal arch form and suggested the use
of the cat...
BRADER ARCH FORM
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By Brader-1972
He stated that dental arch form was
made up of teeth which assume
unique positions a...
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Also called as trifocal-ellipse
Arch form is similar to cantenary
curve but tapers over the second
molar
Several m...
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The geometry of the curve of the
dental arch form was said to be
best approximated by a closed
curve with the curviline...
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Brader recommended an arch guide
with five arch forms.
The selection of the proper arch form
was based on arch wi...
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They differ in size as dictated by
width of second molar
The maxillary arch form is always
one size larger than the ...
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It differs from a cantenary curve in
producing greater width across
premolar
The Brader arch form will more
closely ...
SELECTION OF ARCH WIRE


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Measure the
greatest intermolar
diameter in
millimeter
This measurement
gives the optimum
arc...
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

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The unique geometry of the Brader
arch is that it forms a superior dental
arch form
The primary determinants of arch...
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The geometry of the dental arch
form is so related with the resting
forces of the tongue
PR=C

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The lips and cheek exert inward
counterbalancing tension against the
teeth

PI=Pe+t{1/R+1/R’}

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Arch form characteristics are such
that the form is stabilized and dental
equilibrium is attained whenever
C=T

www.ind...
DRAWBACK OF BRADER
ARCH FORM
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Many clinicians found that this
arch form created excessive
narrowing in the cuspid region...
VARI-SIMPLEX ARCH FORM


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By Dr Garland McEvain-baylor
university
He studied 102 treated cases of Dr
Alexander and foun...
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The anterior section of Vari-simplex
arch forms is flatter than PAR arch
forms and more pointed compared to
roth arch f...
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TYPES OF ARCH FORM

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Vari simplex arch form serves merely
as treatment guide, they never
intended to be final arch wire
Final mandibular ...
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Care is taken to determine that
cuspids are not expanded
Mandibular expansion occures in
molar and premolar regio...
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Dr Alexander does not correlate arch
form to the facial type to keep the
cuspid stable.
He does not use Tweeds conce...
PENTAMORPHIC ARCHES
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By Ricketts
Atleast 10 factors needed to be
taken into account in the research of
arch form

www....
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This includes
-Arch correlation
-Arch size
-Arch length
-where the arch to be measured
-contact details
-final determin...
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Twelve arch forms were originally
identified, these were narrowed
down to 5 by ricketts and are called
as pentamorphic ...
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They are
-narrow ovoid
-ovoid
-normal ideal
-tapered
-narrow tapered

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NARROW OVOID

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OVOID
NORMAL IDEAL

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TAPERED

NARROW TAPERED

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ROTH TRU-ARCH FORMS


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The Roth Tru-Arch form was derived from
his extensive clinical testing and recording
of jaw-move...
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Roth notes that superimposition of
his Tru-Arch form on Ricketts normal
form shows that they coincides
almost exactl...
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Arch width varies with facial type
the brachyprosopic arch is seldom
more than 2-3mm wider than the
dolichoprosopic arc...
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The widest point in the entire arch is
at the 1st molars, but in the front part
of the arch, the widest part is in the
...
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There are actually 5 arcs in the arch
-1) the arc acros front
-2,3) another arc in each cuspid ,
bicuspid region
-4,5)a...
TYPES
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TAPERED
OVOID
SQUARE

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STRAIGHT WIRE TECHNIQUE
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The arch wire used in this technique
is slightly expanded in the bicuspid
region to allow prope...
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M.B.T ARCH FORM
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M.B.T technique uses arch form
used by chuck(1932)
Classified by chuck in 1932
Tapered (narrow)
Ovoi...
TAPERED
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Ovoid arch form
has the narrowest
inter canine width
Used in
-gingival recession
in canine and
premolar regi...
OVOID
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Preferred arch form
Has resulted in
good stability
When
superimposed with
tapered arch form
there is 6mm
dif...
SQUARE
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Used in cases with
broad arch forms,
Useful atleast in
part of the
treatment in cases
requiring
expansion of ...
ANDREIKO THEORY OF ARCH
FORM
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By Andreiko et al -1994
Shape of the mandible should
dectate arch form,with the teeth
al...
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ADVANTAGES
-The arch form are derived from
the skeletal and dental anatomy and
are therefore designed to be closer
to a...
ARCH FORM CONSIDERATIONS
IN BEGG TREATMENT
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Dr BEGG –each patient is an entity
unto himself, as far as the most
favorabl...
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MOLLENHAUER-There has not been
the rigorous teaching of arch form in
begg technique as in edgewise.
Neglect-due to t...


An arch wire as light as 0.016” can
alter the arch form if kept in the
brackets for few months

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METHOD TO DRAW INDIVIDUAL
ARCH FORM


The arch form consists of 3
segments – an anterior segment
between the two canine t...


The dimensions and curvetures of
these segments depends on
1)-anterior tooth materialdetermines the anterior segment
le...
2)-width across the cusp tips of 33,43,
mesio buccal cusp of 36,46 and disto
buccal cusp of 37,47 determines the
transvers...
3)-arch length measured as
perpendicular distance from the mid
point between 31,41 to the line
joining the tips of disto b...
DRAWING A ARCH FORM
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Obtain the above said measurements
from patient
Draw a midline on a graph paper
Transfer the c...


Take a 4” long 0.016” s.S wire.Mark
on it the length of the anterior
segment,the wire is flexed such thar
these pointsl...


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Location of mesio buccal cusps of
first molars are marked exactely and
the canine marking is extended to it
using a ...
COMPUTER PREDICTION

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Schulof-1975
Various other arch form have been
constructed using algebraic
equations

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

Arch form are produced from
measurements of intermolar width,
intercanine width and arch depth
from labial surface of i...
OTHER ARCH FORMS


Williams -1917 described anterior
teeth as lying on the arc of a circle
with its centre midway between...
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Sicher-1952-upper arch-elliptical,
lower arch-parabolic
Baz -1958 determined normal arch
size by a geometric constru...
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Kato-1964 no great disparity
between arches, same arch form
may be classified differently by
different workers
Lu 19...
THE RELAPSE TENDENCY INHERENT IN
ARCH FORM CHANGES
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MCCAULEY,STRANG,GRABER,AND
ERSON,HUGGINS,MILLS,LUDWIG
--numerous aut...


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Walter- reported the
maintenance of slight increase in
mandibular inter-cuspid width
after all retention had been
re...
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Steadman also reported similar
results.
Arnold later pointed out that at
least five years must elapse
before an appa...


In 1976 Gardner studied intercuspid, inter-first bicuspid, intersecond bicuspid and inter-molar
widths, as well as arch...
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1. Inter-cuspid width was expanded
during treatment but had a strong
tendency to return to or close to its
original ...




3. Second bicuspid width for nonextraction cases showed a
significant amount of increase
with a slight tendency for ...


5. The inter-molar width of
nonextraction cases showed
signifi- cant increase in width
with treatment and the
extractio...


6. The incisor to inter-molar
distance decreased with
treatment and had a slight
tendency to continue to decrease
post-...


In 1995 De La Cruz, et al.,
studied the long term changes in
arch form of 45 Class I and 42
Class II Division 1 cases a...


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They concluded that arch form
tended to return toward the pretreatment shape after retention
and that the greater th...
NORMAL GROWTH AND
DEVELOPMENT


Arch dimensions changes with
growth, it is therefore necessary to
distinguish changes ind...


MOORREES-has pointed out that
considerable individual variations in
arch form will occur with normal
growth, with a gen...


It is difficult to predict the growth
potential in induvidual patients, but
information is available on the
average cha...


The average changes reported by
Moyers et al shows changes in arch
width vary between males and
females and that more g...


SINCLAIR et al have confirmed that the
increase in molar width after age 12 is
statistically different in males and fem...
-upper and lower inter molar width
increase spontaneously to a
considerable extent between ages of
7 and 18 in males
-litt...


-changes in arch width may not be
accompanied by changes in arch
length,there is a tendrncy towards a
decrease in arch ...
APPLIANCE INDUCED GROWTH


It is difficult to determine the
contribution of appliance, as a
normal growth change would be...


McNAMARA and BURDON-it seems
logical to consider increasing arch
size at a young age so that
skeletal ,dentoalveolar, a...


An appliance inserted in an actively
growing patients, shows a favorable
response,however this response may
have occurr...


SPILLANCE and McNAMARA
-Examined the records of PATIENTS IN
THE Michigan study who presented with
narrow arch forms and...
INTER CANINE WIDTH


LEWIS & LEHMAN & BAUME have
shown that the inter canine width
increases during eruption of
permanent...


DUTERLOO and BIERMAN show that the
alveolar crest is relatively inactive after
the deciduous teeth erupt, but it is mos...
FACIAL FORM VS ARCH FORM




dolicocephalic form --longer but
narrower and deeper maxillary arch
and palate.
Brachy ceph...
ROLE OF SOFT TISSUE MATRIX
IN MAINTAINING ARCH FORM;


Frankel postulates that the increase
in crowding is the result of
...





The equilibrium theory states that
the positions of the teeth are
determined by the balance between
the intrinsic ...




ORAL RESPIRATION- Ricketts has
shown that mouth breathing tends to
lead to narrow arches, cross bites
and increased ...
AJO 1980 January

Anoop Sondhi, John F. Cleall and
Ellar A. Be Gole

Distal movements of canines during
treatment does n...
Analysis of change in arch form
with premolar expansion




Ellen A.BeGole, Cyril Sadowsky (Ajo1998)
The arch forms of 3...


Significant stable expansion of the
premolar and molar widths may be
possible in both the maxillary and
mandibular arch...
Upper dental arch morphology of adult
unoperated complete bilateral cleft lip and
palate
 Omar Gabriel, daSilva Filho.(Aj...


· Gender has a differential effect on
the maxillary arches of cleft and
noncleft patients; significant
differences are ...




· BCLP results in an anteriorly
progressive constriction of the upper
dental arch in both genders.
· The BCLP group ...
CONCLUSION


Clinicians should be cautious when
treating to mathematically derived
arches, since studies have not
determi...
Thank you

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Arch Form in orthodontics /certified fixed orthodontic courses by Indian dental academy

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Arch Form in orthodontics /certified fixed orthodontic courses by Indian dental academy

  1. 1. ARCH FORM INDIAN DENTAL ACADEMY Leader in continuing dental education www.indiandentalacademy.com www.indiandentalacademy.com
  2. 2. INTRODUCTION   The achievement of a stable, functional and esthetic arch form has long been one of the prime objectives of orthodontics Despite numerous investigations, there is little agreement as to the best size and shape for an ideal orthodontic arch form. www.indiandentalacademy.com
  3. 3.   Various authors have used different curved mathemetical models,but stability of these arch forms has not been established The mandibular dental arch is considered as a reference element of diagnosis and therapy in dentofacial orthopedics. www.indiandentalacademy.com
  4. 4. DEFINITION  ARCH FORM-position and relationship the teeth have with each other in all 3 dimensions www.indiandentalacademy.com
  5. 5. -It is the collective response of all teeth to all of the environment forces and their resultant positions in the oral cavity (Brader-1974) www.indiandentalacademy.com
  6. 6.  -dental arch form is made up of teeth which assumes unique positions along a compound curve representing an equilibrium at all points and delimited by the counterbalancing force fields of the tongue and of the circumoral tissues(Brader) www.indiandentalacademy.com
  7. 7. DETERMINATION OF ARCH FORM  Determined by -skeletal pattern -muscular forces “ neutral zone” ( Mills 1968) www.indiandentalacademy.com
  8. 8. TYPES OF ARCH FORM                BONWILL HAWLEY ELLIPSE PARABOLA CHUCKS –ARCH FORM CANTENARY CURVE BRADER PENTAMORPHIC COMPUTER PRIDICTION VARI-SIMPLEX DESIGN ROTH TRUE ARCH STRAIGHT WIRE M.B.T BEGG ARCH FORM LINGUAL ARCH FORM www.indiandentalacademy.com
  9. 9. BONWILL  In 1885, he noted the tripod shape of the lower jaw and declared that it formed an equilateral triangle with the base extending from condyle to condyle and the sides extending from each condyle to the midline of the central incisors. www.indiandentalacademy.com
  10. 10.  He stated that this triangle existed for the proper functioning of the teeth. Importantly, he noted that the bicuspids and molars formed a straight line from the cuspids to the condyles. www.indiandentalacademy.com
  11. 11. HAWLEY   In 1905, Hawley employed some of Bonwill’s principles in proposing a geometric method for constructing the ideal arch form. Hawley suggested that the six anterior teeth be made to lie along a circle whose radius equaled their combined widths. From this circle he created an equilateral Triangle, the base of which represented the intercondylar width. www.indiandentalacademy.com
  12. 12.   It was proposed that the bicuspids and molars should be aligned along these extended straight lines. Hawley did, however, advised against the strict use of this method for determining arch form, and that it be used only as a guide in establishing arch form. www.indiandentalacademy.com
  13. 13.    Arch form is constant for all induviduals The radius of the arch varied depending on the size of the anterior teeth This arch form is no longer recommended www.indiandentalacademy.com
  14. 14. CONSTRUCTION www.indiandentalacademy.com
  15. 15. www.indiandentalacademy.com
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  18. 18. www.indiandentalacademy.com
  19. 19. www.indiandentalacademy.com
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  21. 21. www.indiandentalacademy.com
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  23. 23. PARABOLA  Angle , 1907, - Defined “line of occlusion”, as being “the line with which, in form and position according to type, the teeth must be in harmony If in normal occlusion”. The form Of this line was said to resemble a Parabolic curve but one that varied greatly due to race, type, temperament, etc. of the individual. www.indiandentalacademy.com
  24. 24. PARABOLA  By E.H.Angle in 1906 Fits as well as any ideal arch Ignors narrowing of arch form over the second molars www.indiandentalacademy.com
  25. 25. www.indiandentalacademy.com
  26. 26.   In describing the First order bends, Angle objected particularly to the straight line proposed from cuspid to third molar. Angle stated that a straight line existed from the cuspid to the mesiobuccal cusp of the first molar, however, there was a natural curvature needed in the molar region. www.indiandentalacademy.com
  27. 27.  Landmarks A,D,D’,E,E’ www.indiandentalacademy.com
  28. 28. GRAY  In 1942, Gray’s Anatomy stated : “The maxillary dental arch forms an elliptical curve...The mandibular dental arch forms a parabolic curve” www.indiandentalacademy.com
  29. 29. CHUCK   Chuck -In 1934, noted the variation in human arch form and pointed out that arch forms had been referred to as square, round, oval, tapering. He stated that while the BonwillHawley arch form was not suitable for use in each patient, it could serve as a template for the construction of individualized arch forms. www.indiandentalacademy.com
  30. 30.   Chuck superimposed this arch form on a millimeter grid and used this template for archwire construction according to Angle’s method. Chuck suggested that the bicuspid regions should be wider than the cuspids to prevent excessive expansion of the cuspids. www.indiandentalacademy.com
  31. 31. DRAWBACKS OF PARABOLAELLIPSE ARCH FORM   MacConaill -1949, stated that, in considering the line of occlusion, it would be impossible for an ellipse and a parabola to meet one another at every point. He concluded that the ellipseparabola description of the two dental arches, although elegant, had no immediate relation to function. www.indiandentalacademy.com
  32. 32. BLACK  In 1902, he stated that the upper teeth are arranged in a semiellipse and that the lower teeth were arranged similarly on a smaller curve. www.indiandentalacademy.com
  33. 33. CATENARY CURVE   Mcconnail and scher -1949 He stated that the catenary curve, fit so many cases with exactness that it could be taken as the “ideal curve” of common occlusions. www.indiandentalacademy.com
  34. 34.   Shape formed by a length of chain held at each end and allowed to drop Catenary curve could be described as a central core or central perimeter around which teeth arrange themselves www.indiandentalacademy.com
  35. 35. www.indiandentalacademy.com
  36. 36.   Ignores narrowing of archform over the second molar The length of the chain and the distance between the supports determine the precise shape of the curve www.indiandentalacademy.com
  37. 37.   Catenary curve fits the dental arch form of the premolar-canine-incisor segment of a arch very nicely for most individuals The curve doesn’t fit accurately if it is extended posteriorly, because the dental arch normally curves lingually in the second and third molar region www.indiandentalacademy.com
  38. 38.    Catenary curve a better representation of mandibular dental arch Ellipse or parabola represents maxillary arch (Neilans-1968) Catenary curve is a good fit in 27%of the samples studied (White LW-1977) www.indiandentalacademy.com
  39. 39.  In 1957, Scott also supported the concept of the catenary curve as the shape of the human arch based on the developmental anatomy of the dental arches and surrounding anatomic structures. www.indiandentalacademy.com
  40. 40.  He pointed out that the basal bone of the maxilla and mandible remains much more constant in form in all mammals and forms a foundation on which a great deal of variation in form of alveolar processes are constructed www.indiandentalacademy.com
  41. 41.  Burdi and Lillie in 1966 stated that the basic bony arch is established as early as 9.5 weeks in utero and that this form was that of the catenary curve. www.indiandentalacademy.com
  42. 42.   Musich, in 1973, supported the concept of the catenary curve as the ideal arch form and suggested the use of the catenometer as a reliable device for construction of arch perimeter. The catenary curve creates a rather tapered arch form and many of the tapered arch forms provided by orthodontic manufacturers today are based on the catenary curve. www.indiandentalacademy.com
  43. 43. BRADER ARCH FORM   By Brader-1972 He stated that dental arch form was made up of teeth which assume unique positions along a compound curve representing an equilibrium at all points and delimited by the counterbalancing forces of the tongue and circumoral tissues. www.indiandentalacademy.com
  44. 44.    Also called as trifocal-ellipse Arch form is similar to cantenary curve but tapers over the second molar Several manufacturers use Brader arch form www.indiandentalacademy.com
  45. 45. www.indiandentalacademy.com
  46. 46. www.indiandentalacademy.com
  47. 47.  The geometry of the curve of the dental arch form was said to be best approximated by a closed curve with the curvilinear properties inherent in the trifocal ellipse, with the teeth occupying only the portion at the constricted end of the curve. www.indiandentalacademy.com
  48. 48.    Brader recommended an arch guide with five arch forms. The selection of the proper arch form was based on arch width at the second molars as measured at the facial, gingival surface. The maxillary archform was selected one size larger than the mandibular arch form. www.indiandentalacademy.com
  49. 49.   They differ in size as dictated by width of second molar The maxillary arch form is always one size larger than the mandibular arch form www.indiandentalacademy.com
  50. 50.   It differs from a cantenary curve in producing greater width across premolar The Brader arch form will more closely approximate the normal position of the second and third molars www.indiandentalacademy.com
  51. 51. SELECTION OF ARCH WIRE   Measure the greatest intermolar diameter in millimeter This measurement gives the optimum arch curve on guide chart www.indiandentalacademy.com
  52. 52. www.indiandentalacademy.com
  53. 53.   The unique geometry of the Brader arch is that it forms a superior dental arch form The primary determinants of arch form morphology are the tissue force in resting state www.indiandentalacademy.com
  54. 54.   The geometry of the dental arch form is so related with the resting forces of the tongue PR=C www.indiandentalacademy.com
  55. 55.   The lips and cheek exert inward counterbalancing tension against the teeth PI=Pe+t{1/R+1/R’} www.indiandentalacademy.com
  56. 56.  Arch form characteristics are such that the form is stabilized and dental equilibrium is attained whenever C=T www.indiandentalacademy.com
  57. 57. DRAWBACK OF BRADER ARCH FORM  Many clinicians found that this arch form created excessive narrowing in the cuspid region of many patients and led to excessive wear of the incisal portion of the cuspids. www.indiandentalacademy.com
  58. 58. VARI-SIMPLEX ARCH FORM   By Dr Garland McEvain-baylor university He studied 102 treated cases of Dr Alexander and found 2 arch form which fits to all his cases “u” form and”v” form www.indiandentalacademy.com
  59. 59.  The anterior section of Vari-simplex arch forms is flatter than PAR arch forms and more pointed compared to roth arch forms www.indiandentalacademy.com
  60. 60. www.indiandentalacademy.com
  61. 61. TYPES OF ARCH FORM www.indiandentalacademy.com
  62. 62.   Vari simplex arch form serves merely as treatment guide, they never intended to be final arch wire Final mandibular arch wire is always fitted to the original study model www.indiandentalacademy.com
  63. 63.    Care is taken to determine that cuspids are not expanded Mandibular expansion occures in molar and premolar region The maxillary arch form is built to fit the mandibular arch form www.indiandentalacademy.com
  64. 64.   Dr Alexander does not correlate arch form to the facial type to keep the cuspid stable. He does not use Tweeds concept of co-relating upper and lower arch wires since similar arch wires are not placed in upper and lower arch at the same time www.indiandentalacademy.com
  65. 65. PENTAMORPHIC ARCHES   By Ricketts Atleast 10 factors needed to be taken into account in the research of arch form www.indiandentalacademy.com
  66. 66.  This includes -Arch correlation -Arch size -Arch length -where the arch to be measured -contact details -final determination of the bracket location www.indiandentalacademy.com
  67. 67.  Twelve arch forms were originally identified, these were narrowed down to 5 by ricketts and are called as pentamorphic arches www.indiandentalacademy.com
  68. 68.  They are -narrow ovoid -ovoid -normal ideal -tapered -narrow tapered www.indiandentalacademy.com
  69. 69. NARROW OVOID www.indiandentalacademy.com OVOID
  70. 70. NORMAL IDEAL www.indiandentalacademy.com
  71. 71. TAPERED NARROW TAPERED www.indiandentalacademy.com
  72. 72. ROTH TRU-ARCH FORMS   The Roth Tru-Arch form was derived from his extensive clinical testing and recording of jaw-movement pattern in treated patients who were out of retention and had stable results Comparison with arch form derived by Andrews from measurement of his 120 normal cases shows that the Roth arch form is wider by few millimeter in the bicuspid region www.indiandentalacademy.com
  73. 73.   Roth notes that superimposition of his Tru-Arch form on Ricketts normal form shows that they coincides almost exactley The Roth Tru-Arch form actually overcorrects the arch width slightly;over correction is part of roths goal www.indiandentalacademy.com
  74. 74.  Arch width varies with facial type the brachyprosopic arch is seldom more than 2-3mm wider than the dolichoprosopic arch, but the individual jaw width may wary more and the arch wire should be adjusted to harmonize www.indiandentalacademy.com
  75. 75.  The widest point in the entire arch is at the 1st molars, but in the front part of the arch, the widest part is in the bicuspids and not cuspids www.indiandentalacademy.com
  76. 76.  There are actually 5 arcs in the arch -1) the arc acros front -2,3) another arc in each cuspid , bicuspid region -4,5)a uniform curve in the buccal segment www.indiandentalacademy.com
  77. 77. TYPES    TAPERED OVOID SQUARE www.indiandentalacademy.com
  78. 78. STRAIGHT WIRE TECHNIQUE  The arch wire used in this technique is slightly expanded in the bicuspid region to allow proper functional movements and it is close to roth arch forms www.indiandentalacademy.com
  79. 79. www.indiandentalacademy.com
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  81. 81. www.indiandentalacademy.com
  82. 82. M.B.T ARCH FORM   M.B.T technique uses arch form used by chuck(1932) Classified by chuck in 1932 Tapered (narrow) Ovoid (normal) Square (broad) www.indiandentalacademy.com
  83. 83. TAPERED   Ovoid arch form has the narrowest inter canine width Used in -gingival recession in canine and premolar region -single arch treatment cases www.indiandentalacademy.com
  84. 84. OVOID    Preferred arch form Has resulted in good stability When superimposed with tapered arch form there is 6mm difference in canine region www.indiandentalacademy.com
  85. 85. SQUARE   Used in cases with broad arch forms, Useful atleast in part of the treatment in cases requiring expansion of upper arch, buccal uprighting of lower posteriors www.indiandentalacademy.com
  86. 86. ANDREIKO THEORY OF ARCH FORM   By Andreiko et al -1994 Shape of the mandible should dectate arch form,with the teeth aligned and contained with in the limits of the mandibular bone www.indiandentalacademy.com
  87. 87.  ADVANTAGES -The arch form are derived from the skeletal and dental anatomy and are therefore designed to be closer to an anatomic ideal than mathemetical ideal -Individualized treatment is simplified www.indiandentalacademy.com
  88. 88. ARCH FORM CONSIDERATIONS IN BEGG TREATMENT  Dr BEGG –each patient is an entity unto himself, as far as the most favorable arch form should bear in relation to rest of the face and skull www.indiandentalacademy.com
  89. 89.   MOLLENHAUER-There has not been the rigorous teaching of arch form in begg technique as in edgewise. Neglect-due to the belief that use of light wires could not alter the patients original arch form ( but this is not true) www.indiandentalacademy.com
  90. 90.  An arch wire as light as 0.016” can alter the arch form if kept in the brackets for few months www.indiandentalacademy.com
  91. 91. METHOD TO DRAW INDIVIDUAL ARCH FORM  The arch form consists of 3 segments – an anterior segment between the two canine teeth, and 2 posterior segments from canine to molars on either side www.indiandentalacademy.com
  92. 92.  The dimensions and curvetures of these segments depends on 1)-anterior tooth materialdetermines the anterior segment length from one canine cusp to the other canine cusp www.indiandentalacademy.com
  93. 93. 2)-width across the cusp tips of 33,43, mesio buccal cusp of 36,46 and disto buccal cusp of 37,47 determines the transverse dimension of the arch www.indiandentalacademy.com
  94. 94. 3)-arch length measured as perpendicular distance from the mid point between 31,41 to the line joining the tips of disto buccal cusps of 37-47,determines the sagittal dimension of the arch www.indiandentalacademy.com
  95. 95. DRAWING A ARCH FORM    Obtain the above said measurements from patient Draw a midline on a graph paper Transfer the canine locations on the graph paper on either side of the arch midline www.indiandentalacademy.com
  96. 96.  Take a 4” long 0.016” s.S wire.Mark on it the length of the anterior segment,the wire is flexed such thar these pointslie on the canine location in graph,the wire gives the anterior curvature www.indiandentalacademy.com
  97. 97.   Location of mesio buccal cusps of first molars are marked exactely and the canine marking is extended to it using a straight or curved line The upper arch form is drawn parallel to and outside the lower arch form keeping a distance of 2-3 mm www.indiandentalacademy.com
  98. 98. COMPUTER PREDICTION   Schulof-1975 Various other arch form have been constructed using algebraic equations www.indiandentalacademy.com
  99. 99.  Arch form are produced from measurements of intermolar width, intercanine width and arch depth from labial surface of incisors to last standing molars www.indiandentalacademy.com
  100. 100. OTHER ARCH FORMS  Williams -1917 described anterior teeth as lying on the arc of a circle with its centre midway between the buccal grooves of 1st molar www.indiandentalacademy.com
  101. 101.   Sicher-1952-upper arch-elliptical, lower arch-parabolic Baz -1958 determined normal arch size by a geometric construction based on measurements taken from patient’s face www.indiandentalacademy.com
  102. 102.   Kato-1964 no great disparity between arches, same arch form may be classified differently by different workers Lu 1964 dental arch could be described by a polynomial equation of the 4th degree www.indiandentalacademy.com
  103. 103. THE RELAPSE TENDENCY INHERENT IN ARCH FORM CHANGES  MCCAULEY,STRANG,GRABER,AND ERSON,HUGGINS,MILLS,LUDWIG --numerous authors who had reported that when inter-cuspid and inter-molar width had been changed during orthodontic treatment, there was a strong tendency for these teeth to return to their pre-treatment position. www.indiandentalacademy.com
  104. 104.   Walter- reported the maintenance of slight increase in mandibular inter-cuspid width after all retention had been removed for what was termed an adequate period. . www.indiandentalacademy.com
  105. 105.   Steadman also reported similar results. Arnold later pointed out that at least five years must elapse before an apparent maintenance of increase in inter-cuspid width could be accepted www.indiandentalacademy.com
  106. 106.  In 1976 Gardner studied intercuspid, inter-first bicuspid, intersecond bicuspid and inter-molar widths, as well as arch length changes in 103 cases, 74 of which were treated nonextraction, and 29 of which were treated with extraction of four first bicuspids. His conclusions were as follows: www.indiandentalacademy.com
  107. 107.   1. Inter-cuspid width was expanded during treatment but had a strong tendency to return to or close to its original pre-treatment width in both non-extraction and extraction cases. 2. It would appear that the inter-first bicuspid width showed the greatest treatment increase in width with only a minimal amount of post-treatment width decrease. www.indiandentalacademy.com
  108. 108.   3. Second bicuspid width for nonextraction cases showed a significant amount of increase with a slight tendency for postretention decrease. 4. Second bicuspid width for extraction cases showed a decrease with treatment and a slight continued decrease postretention. www.indiandentalacademy.com
  109. 109.  5. The inter-molar width of nonextraction cases showed signifi- cant increase in width with treatment and the extraction cases showed a significant decrease with treatment, However there were no changes in either extraction or non-extraction cases postretention. www.indiandentalacademy.com
  110. 110.  6. The incisor to inter-molar distance decreased with treatment and had a slight tendency to continue to decrease post-retention. www.indiandentalacademy.com
  111. 111.  In 1995 De La Cruz, et al., studied the long term changes in arch form of 45 Class I and 42 Class II Division 1 cases after orthodontic treatment and a minimum of 10 years post retention. www.indiandentalacademy.com
  112. 112.   They concluded that arch form tended to return toward the pretreatment shape after retention and that the greater the treatment change, the greater the tendency for post-retention change. They suggested that the patient’s pre-treatment arch form appeared to be the best guide for future arch form stability, www.indiandentalacademy.com
  113. 113. NORMAL GROWTH AND DEVELOPMENT  Arch dimensions changes with growth, it is therefore necessary to distinguish changes induced by appliance therapy from those that occur from natural growth www.indiandentalacademy.com
  114. 114.  MOORREES-has pointed out that considerable individual variations in arch form will occur with normal growth, with a general tendency towards an increase in the intermolar width during the change over from the decidous to permanent dentition. www.indiandentalacademy.com
  115. 115.  It is difficult to predict the growth potential in induvidual patients, but information is available on the average changes in arch dimension in centered samples www.indiandentalacademy.com
  116. 116.  The average changes reported by Moyers et al shows changes in arch width vary between males and females and that more growth in width occurs in upper than the lower arch, this growth occurs mainly between 7 to 12 years of age, after 12years growth in width is seen only in males www.indiandentalacademy.com
  117. 117.  SINCLAIR et al have confirmed that the increase in molar width after age 12 is statistically different in males and females. -Male arches grow wider than female arches -Lower intercanine width increases significantly in the change over dentition but does not increase in permanent dentiton after 12 years of age www.indiandentalacademy.com
  118. 118. -upper and lower inter molar width increase spontaneously to a considerable extent between ages of 7 and 18 in males -little changes in arch width occurs in the premolar region after age of 12 www.indiandentalacademy.com
  119. 119.  -changes in arch width may not be accompanied by changes in arch length,there is a tendrncy towards a decrease in arch depth in third and forth decades www.indiandentalacademy.com
  120. 120. APPLIANCE INDUCED GROWTH  It is difficult to determine the contribution of appliance, as a normal growth change would be expected for each individual www.indiandentalacademy.com
  121. 121.  McNAMARA and BURDON-it seems logical to consider increasing arch size at a young age so that skeletal ,dentoalveolar, and muscular adoptations can occur before the eruption of permanent dentition. www.indiandentalacademy.com
  122. 122.  An appliance inserted in an actively growing patients, shows a favorable response,however this response may have occurred in the absence of treatment,the relative contribution of appliance being difficult to determine www.indiandentalacademy.com
  123. 123.  SPILLANCE and McNAMARA -Examined the records of PATIENTS IN THE Michigan study who presented with narrow arch forms and compared them with the average sample. result show that those with initially narrow arch forms tend to become more average, and ppliance therapy is therefore more likely to achieve a stable change www.indiandentalacademy.com
  124. 124. INTER CANINE WIDTH  LEWIS & LEHMAN & BAUME have shown that the inter canine width increases during eruption of permanent incisors and again during eruption permanent canines www.indiandentalacademy.com
  125. 125.  DUTERLOO and BIERMAN show that the alveolar crest is relatively inactive after the deciduous teeth erupt, but it is most active during eruption of permanent teeth and then becomes relatively inactive again after the permanent teeth have erupted. Therefore if mandibular lateral expansion is ever to be considered, the optimal time is prior to and during eruption of permanent teeth www.indiandentalacademy.com
  126. 126. FACIAL FORM VS ARCH FORM   dolicocephalic form --longer but narrower and deeper maxillary arch and palate. Brachy cephalic type --wider but shorter and more shallow palate and maxillary arch. www.indiandentalacademy.com
  127. 127. ROLE OF SOFT TISSUE MATRIX IN MAINTAINING ARCH FORM;  Frankel postulates that the increase in crowding is the result of hypertonic muscles in the buccinator mechanism restricting the lateral growth of teeth and their supporting tissues. www.indiandentalacademy.com
  128. 128.    The equilibrium theory states that the positions of the teeth are determined by the balance between the intrinsic forces of tongue, lips, dental occlusion, and periodontal ligament Supported by Tomes-1873 Opposed by Scott-1967 www.indiandentalacademy.com
  129. 129.   ORAL RESPIRATION- Ricketts has shown that mouth breathing tends to lead to narrow arches, cross bites and increased crowding Linder-Aronson and backstrom report that children scheduled for adenoidectomy generally have longer, more narrow faces than control children www.indiandentalacademy.com
  130. 130. AJO 1980 January  Anoop Sondhi, John F. Cleall and Ellar A. Be Gole  Distal movements of canines during treatment does not ensure stable increase in mandiular inter canine width. www.indiandentalacademy.com
  131. 131. Analysis of change in arch form with premolar expansion   Ellen A.BeGole, Cyril Sadowsky (Ajo1998) The arch forms of 38 cases in which expansion, while maintaining arch form, were analyzed before treatment, after treatment, and an average of 6 to 8 years after retention. www.indiandentalacademy.com
  132. 132.  Significant stable expansion of the premolar and molar widths may be possible in both the maxillary and mandibular arches in nonextraction cases. www.indiandentalacademy.com
  133. 133. Upper dental arch morphology of adult unoperated complete bilateral cleft lip and palate  Omar Gabriel, daSilva Filho.(Ajo 1999)  Cast model analysis of the maxillary dental casts of 31 adult persons with unoperated complete BCLP and those of a matched sample of 31 noncleft patients indicate the following: www.indiandentalacademy.com
  134. 134.  · Gender has a differential effect on the maxillary arches of cleft and noncleft patients; significant differences are present in the noncleft group (wider and longer arches in males), but not in the unoperated cleft group. www.indiandentalacademy.com
  135. 135.   · BCLP results in an anteriorly progressive constriction of the upper dental arch in both genders. · The BCLP group has a significantly longer maxillary dental arch, which is attributed to the premaxillary anterior projection. www.indiandentalacademy.com
  136. 136. CONCLUSION  Clinicians should be cautious when treating to mathematically derived arches, since studies have not determined conclusively what that shape might be www.indiandentalacademy.com
  137. 137. Thank you Thank you For more details please visit www.indiandentalacademy.com www.indiandentalacademy.com

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