Download Evaluation of arch dimensional changes after

Advances in Biology & BioMedicine
www.advancejournals.org
Open Access Scientific Publisher
Research Article
EVALUATION OF ARCH DIMENSIONAL CHANGES AFTER
ORTHODONTIC TREATMENT IN EXTRACTION AND NONEXTRACTION CASES. AN IN-VITRO STUDY
S Narayanan1, C Sabarigirinathan2, K Vinayagavel2, P Rupkumar2, M Kanmani2, K Venkata Seetha Lakshmi2
1
Private Practitioner, Dubai, UAE
2
Department of Prosthodontics, Tamil Nadu Government Dental College and Hospital, Chennai,India
Correspondence should be addressed to S Narayanan
Received March 20, 2015; Accepted March 28, 2015; Published May 05, 2015;
Copyright: © 2015 S NARAYANAN et al. This is an open access article distributed under the Creative Commons
Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the
original work is properly cited.
Cite This Article:Narayanan, S., Sabarigirinathan, C., Vinayagavel, K., Rupkumar, P., Kanmani, M., Venkata Seetha
Lakshmi, K .(2015). Evaluation of arch dimensional changes after orthodontic treatment in extraction and nonextraction cases. An in-vitro study. Advances in Biology & BioMedicine, 2(1). 1-8
ABSTRACT
Orthodontic treatment for malocclusion correction may involve extraction or non-extraction of specified teeth for esthetic
and functional harmony. Antero-posterior and transverse arch dimensional changes following orthodontic treatment has
been evaluated using many methods. The present study evaluated the arch dimensional changes after orthodontic treatment
in extraction and non-extraction cases using AUTO CAD system with medial and lateral edges of 3 rd primary rugae and
mesio-incisal tip of the most prominent incisor as the reference points. A total of 100 (Group 1- Upper bicuspid
extraction=50; Group 2- Non-extraction=50) orthodontically treated cases were selected in the age range of 19-25 years
(Males=50; Females=50). Their pre and post treatment study models were collected and photographed. The photographic
data was then digitized and arch dimensional changes were measured using AUTO CAD. The data obtained were subjected
to statistical analyses using Paired t-test, Unpaired t-test,Levene's test and Gain score measurement test. There were
significant antero-posterior tooth movements in extraction cases when compared to non extraction cases, a significant
reduction in the intermolar width after premolar extractions but minimal changes in the intercanine width showing
significance at 5% level. In non-extraction cases, there was no significant arch dimensional changes after orthodontic
treatment in both intermolar and intercanine region. Maximum antero-posterior arch dimensional changes can be seen in
orthodontically treated bicuspid extraction cases and non extraction cases show minimal changes in the antero-posterior
dimensions even after orthodontic treatment. Significant amount of anchorage loss can be seen in upper bicuspid extraction
cases when compared to non extraction cases. Reduction in the intermolar width and contraction of maxillary arch occurred
in upper bicuspid extraction cases with minimal changes in the intercanine width. Minimal transverse arch dimensional
changes occurred in non-extraction cases after orthodontic treatment.
KEYWORDS: Arch width changes, extraction Vs non-extraction
INTRODUCTION
Correction of malocclusion is one of the major objectives
of orthodontics. Placing the teeth in their appropriate
antero-posterior positions is an essential aspect of all
orthodontic cases.In orthodontic treatment with the
extraction of bicuspids, based on the anchorage
considerations, either retraction of incisors or protraction of
molars or a combination has been done. This can be
achieved by using various appliances of which Pre-adjusted
Edgewise Appliance system has been the mainstay
nowadays. One of the stable reference landmarks in the
oral cavity is the "palatal rugae" [1][2].These palatal rugae
are a series of mucosal ridges composed of dense
ABB 12|Volume 2|Issue 1|2015
1
Advances in Biology & BioMedicine
connective tissues covered by squamous epithelium,
present on either side of the median palatal raphe behind
the incisive papilla of the anterior palate. They play an
important role in orthodontics to assess the antero-posterior
and transverse movements of the teeth. Lysell in 1957
devised a classification of rugae based on size, shape,
angulation and number [3]. It was further modified by
Thomas & Kotze in 1983 [4]. Based on their
classification,3 categories were formed as 1st, 2nd and 3rd
primary rugae. Various methods have been utilized in the
past to record and interpret rugae pattern which included
direct vision, photographs and palatal print using bubble
gum and dental stone. Thomas & Kotze (1983) indicated
that rugae are unique to each individual and don't change
with age and of constant shape throughout life. Rugae
patterns by virtue of their position are protected from
extreme trauma and are insulated from heat by teeth,
tongue and fatty tissues beneath them. With extraction of
premolars & space closure using fixed appliances,
movement of the teeth occur in the antero-posterior and
transverse direction aided by alternating bone resorption
and apposition at various levels [5]. Routinely, treatment
progress and post treatment changes can be evaluated
using cephalometric superimposition. Limitations using
the cephalometric analysis are radiation hazards, errors due
to operator skills and difficulty in differentiating between
right and left sides of the arch. Previously dental casts were
evaluated using Symmetrography, Stereophotography etc.,
[3]. Two dimensional photography have been used
successfully by Huddart in the early 1970's. Following this,
3-D measurements have been utilized to study the dental
casts which include Optocom by Vanderlinden [6] in 1978,
stereophotogrammetry by Savara [7] in 1965. Image
analysis by Brook & Pitts [8] in 1983 and Reflex
metrograph by Almedia [1] in 1995 & Bailey [2] et al. in
1996 had been used to study the rugae pattern in dental
casts. Recent advances in Bio-technology had led to the
analysis of tooth movements that are relative to rugae
points with acceptable method of computers in routine
orthodontic practice [7]. The present study is aimed to
evaluate and assess the antero-posterior tooth movements
as well as to determine the transverse arch dimensional
changes in the intercanine and intermolar region using
third primary rugae as a stable reference landmark in the
dental casts in bicuspid extraction and non-extraction cases
before and after orthodontic treatment using AUTO-CAD.
MATERIALS AND METHODS
2
A total of 100 dento-alveolar malocclusion cases treated
with bicuspid extraction and non extraction using PEA
system with good treatment records were selected.
Surgical and dento-facial deformity cases were excluded
from the study. Models with poor clarity of the rugae
pattern were also eliminated. Selected cases were in the
age group of 19-25yrs. Of these,50 were males & 50 were
females. 50 cases were ( Group 1) bicuspid extraction and
the other 50 were of (Group 2) non-extraction category.
The photographs of the occlusal view of the study models
were taken by using a digital camera, Nikon cool pix 2000,
mounted on a tripod at a standardized height of about 20
cm from the table parallel to the floor. Study models were
oriented by placing it on the template parallel to the floor,
so that orientation of the pre & post treated models did not
ABB 12|Volume 2|Issue 1|2015
change. All the 100 pre and post treatment study models
were successfully photographed by a professional
photographer. The outline of the third primary rugae were
traced using 0.5mm graphite marker. The medial and
lateral ends of the rugae were marked as MR, LR. The
mesio-incisal tip of the most proclined incisor was marked
as R1, L1 for the respective sides. The mesial contact
points of the first molars were marked as R6, L6. The
above landmarks were used for measuring the anteroposterior arch dimensions. The cusp tip of the canines and
the buccal cusp tip of the first molars on both sides were
also marked for measuring the transverse arch dimensional
changes. The digital images of the models were then fed
into the computer using USB port and flash card reader.
The landmarks were then digitized on the computer using
on-screen digitization technique. After on-screen
digitization, the specified distances were calculated using
AUTOCAD between the points plotted, so that changes in
the antero-posterior and transverse dimensions can be
assessed accurately. The data obtained were subjected to
statistical analyses using Paired t-test, unpaired ttest,Levene's test and Gain score measurement test.
RESULTS
Table 1 shows comparison of the mean values of respective
measurements on right side for Group 1. The mean values
of pre &post treated R1-MR values show significant
amount of antero-posterior tooth movements & space
closure, since 'p' value is less than 0.001 which is
statistically highly significant for extraction cases.
Likewise, mean values of R1-LR, R6-MR, R6-LR were
statistically highly significant, since p-value is 0.000
showing statistical significance at 100% level.
Table 2shows comparison of the mean values of respective
measurements on left side for Group 1. L1-MR, L1-LR,
L6-MR, L6-LR mean values were statistically highly
significant showing significant amount of antero-posterior
tooth movements occurred after orthodontic treatment in
bicuspid extraction cases (Group 1).
Advances in Biology & BioMedicine
Table 1: Comparison of the mean values of respective measurements on right side for Group
Measurement
R1-MR
Pre
Post
R1-LR
Pre
Post
R6-MR
Pre
Post
R6-LR
Pre
Post
Mean(mms)
S.D
t-value
p-value
Correlation
33.385
27.155
5.672
4.164
11.10
0.000
0.715
37.578
31.015
6.346
4.587
11.30
0.000
0.764
30.821
28.529
4.070
4.330
4.41
0.000
0.019
19.721
18.016
3.785
3.440
4.30
0.000
0.703
Table 2:Comparison of the mean values of respective measurements on left side for Group 1
Measurement
L1-MR
Pre
Post
L1-LR
Pre
Post
L6-MR
Pre
Post
L6-LR
Pre
Post
Mean(mms)
S.D
t-value
p-value
Correlation
36.831
28.494
10.359
4.625
6.97
0.000
.595
36.599
29.886
6.402
5.112
14.63
0.000
.865
31.129
29.192
4.335
4.409
4.55
0.000
.764
19.644
17.240
2.954
3.007
6.07
0.000
.559
Table 3: Comparison of the mean values of respective measurements on right side for Group 2
Measurement
R1-MR
Pre
Post
R1-LR
Pre
Post
R6-MR
Pre
Post
R6-LR
Pre
Post
Mean(mms)
S.D
t-value
p-value
Correlation
30.857
29.019
5.382
6.285
3.15
0.003
.761
34.727
32.344
5.824
5.949
3.68
0.001
.698
30.119
30.296
4.364
4.648
0.37
0.714
.717
19.082
18.712
3.683
3.968
0.91
0.367
.720
Table 3 shows comparison of the mean values of respective measurements on right side for Group 2. Statistical analysis
reveals minimal changes between the mean values of pre & post treated cases showing minimal significant p- values for R6MR, R6-LR and significant p-values for R1-MR & R1-LR.
Table 4 shows comparison of the mean values of respective measurements on left side for Group 2. Statistical values reveal
that L1-MR & L1-LR values were highly significant and minimal significance in L6-MR & L6-LR values.
ABB 12|Volume 2|Issue 1|2015
3
Advances in Biology & BioMedicine
Table 5 shows comparison of the mean values of right side for Group I and II. It can be inferred that significant anteroposterior tooth movements occurred in extraction cases when compared to non extraction cases as the p-values were
statistically highly significant for all measurements, except R6-LR value, which is significant at 5% level (not significant).
Table 6 shows comparison of the mean values of left side for Group I and II. It can be inferred that significant changes
occurred in the antero-posterior direction in bicuspid extraction and minimal changes in non extraction cases, since p-values
were statistically highly significant for all measurements.
On the basis of statistical analysis, arch dimensional changes were having statistically highly significant values for
extraction cases when compared to non-extraction cases.
Table 7 shows comparison mean values of pre and post treatment intermolar width (I.M.W) and intercanine width (I.C.W)
in Group 1. A significant reduction in the intermolar width after premolar extractions occurred as statistically highly
significant p-value was obtained, but only minimal changes in the intercanine width showing significance at 5% level. This
shows that there was more mesial migration of the molars and anchorage loss in bicuspid extraction cases.
Table 4: Comparison of the mean values of respective measurements on left side for Group 2
Measurement
L1-MR
Pre
Post
L1-LR
Pre
Post
L6-MR
Pre
Post
L6-LR
Pre
Post
Mean(mms)
S.D
t-value
p-value
Correlation
33.0722
30.7614
5.637
6.315
3.52
0.001
.704
34.5006
32.1284
5.800
6.166
3.96
0.000
.752
30.6766
31.0028
5.225
5.521
0.76
0.452
.841
19.0332
19.4262
3.902
3.942
1.10
0.276
.793
Table 5: Comparison of the mean values of right side for Group 1 and 2
Measurement
R1-mr
Extn
Non extn
R1-lr
Extn
Non extn
R6-mr
Extn
Non extn
R6-lr
Extn
Non extn
4
ABB 12|Volume 2|Issue 1|2015
Mean(mms)
S.D
t-value
p-value
6.230
1.832
3.968
4.121
5.44
0.000
6.502
2.383
4.068
4.579
4.76
0.000
2.291
0.177
3.673
3.401
3.49
0.001
1.704
0.370
2.803
2.874
2.35
0.021
Advances in Biology & BioMedicine
Table 6: Comparison of the mean values of left side for Group 1 and 2
Measurement
Mean(mms)
S.D
t-value
p-value
8.337
2.310
8.464
4.639
4.42
0.000
6.713
2.372
3.245
4.232
5.76
0.000
1.936
0.326
3.007
3.040
3.74
0.000
2.404
0.393
2.799
2.525
5.25
0.000
L1-MR
Extn
Non-EXTN
L1-LR
Ext
Non-extn
L6-MR
Ext
Non-extn
L1-MR
Extn
Non-extn
Table 7: Comparison of mean values of pre and post treatment intermolar width (I.M.W) and intercanine width (I.C.W) in
Group 1
Measurement
I.M.W
Pre
Post
I.C.W
Pre
Post
Mean (mms)
S.D
t-value
p-value
Correlation
65.384
62.632
3.873
3.911
7.50
0.000
.778
34.922
35.530
2.816
2.885
2.30
0.026
.785
Table 8: Comparison of mean values of pre and post treatment intermolar width (I.M.W) and intercanine width (I.C.W) in
Group 2
Measurement
Mean (mms)
S.D
t-value
p-value
Correlation
I.M.W
Pre
Post
I.C.W
Pre
Post
63.624
63.343
5.628
6.702
0.36
0.720
.613
34.787
34.980
2.618
2.768
0.73
0.467
.761
Table 9: Comparison of mean values of pre and post treatment intermolar width (I.M.W) and intercanine width (I.C.W)
between Group 1 and 2
Measurement
Mean (mms)
S.D
t-value
p-value
I.M.W
Extraction
Non Extraction
I.C.W
Extraction
Non Extraction
2.752
0.280
2.593
5.511
2.870
0.005
0.608
0.193
1.869
1.866
1.110
0.270
5
Table 8 shows comparison of mean values of pre and post treatment intermolar width (I.M.W) and intercanine width
(I.C.W) in Group 2. There were no significant arch dimensional changes after non-extraction orthodontic treatment in both
intermolar and intercanine regions.
ABB 12|Volume 2|Issue 1|2015
Advances in Biology & BioMedicine
Table 9 shows comparison of mean values of pre and post treatment intermolar width (I.M.W) and intercanine width
(I.C.W) between Group 1 and 2. There were significant differences between pre & post treatment values for measurements
in the intermolar region and insignificant in the intercanine region.
DISCUSSION
6
Dental study models being an essential diagnostic criteria
serve as a three dimensional record of the dental arch in
diagnosis, treatment planning, assessment of the growth as
well treatment progress. One aspect of the study using
study model is morphometrics of a single model and the
other aspect is comparative morphometrics between two
study models. The third aspect of the study is comparative
morphometrics using stable reference landmark against a
variable landmark. A review of literature reveals that the
third primary rugae is one of the stable reference
landmarks in the oral cavity which does not change with
age or orthodontic treatment [1][2][6]. The reliability and
validity of palatal rugae for assessing treatment changes on
study models has been studied earlier. The results,
however, were inconsistent due to the conventional manual
methods applied for evaluating the data. Therefore,
cephalometric superimposition method has been used as
the most reliable method for assessment of treatment
progress and post treatment changes. But radiation
hazards, inter-operator variations and difficulty in
differentiating between the right and left side shadows of
the arch are few of its limitations. In the present study, we
had attempted to pursue the recent interest to revive the
usage of study models for assessing the arch dimensional
changes before and after orthodontic treatment by the use
of computers for better accuracy. Various techniques have
been advocated in the past for measuring the study models
like using flexible rulers and dividers. Dental casts were
measured
by
devices
like
Symmetrograph,
Stereophotometry by Savara (1965) etc., [3][7]. But
recently more sophisticated 3-D method of analyzing the
dental casts by digitization methods are being used
[6][7][8]. Peavy & Kendrick (1967) using Symmetrograph
evaluated the effect of tooth movements on the palatal
rugae and concluded that only slight morphological
alterations were seen in 127 rugae studied as a result of
tooth movements, indicating that the rugae patterns maybe
clinically acceptable [9]. Vanderlinden (1978) using
Optocom evaluated the tooth movements relative to the
rugae points in non-orthodontically treated individuals and
concluded that the medial & lateral rugae points can be
used for the evaluation of changes in the sagittal direction
of the posterior teeth [6]. Whereas, Bailey (1996) &
Almedia et al.(1996) using Reflex Metrography made a
comparative analysis to evaluate the stability of the rugae
in extraction and non extraction orthodontically treated
cases and concluded that the medial & lateral points of the
third rugae appear to be stable for construction of
anatomical reference points for longitudinal cast analysis
[1][2]. Shearn & Woods et al. (2000), Ong & Woods et al.,
(2001) used WESTCEF program for cephalometric
measurements and digital caliper for study cast
measurements to determine arch dimensional changes with
different premolar extraction patterns [5]. They found that
there was evidence of greater intermolar width reduction
after 2nd premolar extraction than 1st premolar
extractions. They also found that a large amount of
individual variation in incisal and molar changes
ABB 12|Volume 2|Issue 1|2015
accompanied orthodontic treatment involving different
premolar extraction patterns. But their study was based on
mandibular arch dimensional variations. Boley & Sachdeva
(2003) studied Class I bicuspid extraction patterns using
both cephalometric measurements and standardized one to
one occlusal photographs of the study models to evaluate
the tooth movement [10]. Their results showed that
maxillary molar width remained unchanged and there is a
reduction in the maxillary arch length during treatment due
to molar protraction & anterior retraction. Gianelly et al.
(2003) studied the arch dimensional changes after
extraction of first premolars and non-extraction
orthodontically treated cases on study models using
electronic calipers [11]. He measured the intercanine and
intermolar width in the maxillary and mandibular arches
and compared them statistically to determine whether the
dental arches were narrower after extraction treatment.
They found that in both the groups, anterior & posterior
arch width remained the same except for the mandibular
intercanine width which was increased in the extraction
groups. They concluded that extraction of first premolars
does not result in the narrowing of the dental arches.
Recent advances in bio-technology have led to the use of
computers for morphometric evaluation of study models in
routine orthodontic practice. In the present study, a
comparative morphometry on study models was
undertaken to assess the arch dimensional changes due to
orthodontic treatment. Transverse arch dimensional
changes were studied between the cusp tip of canines and
buccal cusp tip of first molars (variable landmark) for
intercanine and intermolar width respectively. Anteroposterior arch dimensional changes were assessed between
the medial and lateral ends of the third primary rugae
(stable landmark) to the mesio-incisal tip of the most
proclined tooth (variable point). 100 study models were
photographed using Nikon cool pix 2000 digital camera,
which was mounted on a tripod at a standardized height of
20cm from the table, with optical zoom standardized to 3x
and using max. pixel size of 2 Mega pixels, so that the
image size captured will be of actual object size. After
recording the photographs of the pre & post
orthodontically treated study models, they were fed into
the computer using specialized device (USB port
&flashcard reader), so that the captured image appears onscreen on the monitor and further measurements can be
derived accurately using AUTOCAD, a computer based
software which has high degree of precision & accuracy for
measuring the distances which are useful in engineering &
architecture [12]. Using the CAD software, a series of
points are plotted on an object and the distance between
them can be measured which will appear in certain
specified units (usually in inches which is converted into
mm). The major advantage claimed is the precision &
accuracy of the CAD system of measurements (accuracy
up to 0.000000001mm). Limitations of the system is that it
is a 2-dimensional system of measuring a 3-D object. Also,
the image captured by the camera in one format (jpeg) will
be converted to a different format (dwg/bmp) and stored by
the CAD software for study. Hence, the actual resolution
of the stored image will be reduced. But, this does not have
Advances in Biology & BioMedicine
any effect upon the accuracy of the measurements obtained
by using AUTOCAD. Results of the study were
statistically analyzed using paired and unpaired 't'tests as
well as gain score measurements.
From Table 1, mean values of R1-MR, R1-LR show a
mean of 6 mm anterior retraction and space closure in
upper premolar extractions cases. Mean values of R6-MR,
R6-LR show a mean of 2-2.5 mm of molar mesial
movement and anchorage loss in extraction cases.
From Table 2, L1-MR, L1-LR values show a mean of 8
mm anterior retraction & space closure in bicuspid
extraction cases in the left quadrant. Mean values of L6MR, L6-MR show a mean of 1.5 - 2 mm mesial molar
movement & anchorage loss in the left quadrant. From
Table 1&Table 2, it may be construed that 1/3rd -1/4th of
the bicuspid extraction space has been found to be
consumed as anchorage loss even in PEA system as in
Begg's technique. At this juncture, it is necessary to
mention that the precise anchorage consideration and mode
of anchorage conservation, if any used, couldn't be
obtained in most of the cases studied.
Table 3&Table 4 show the mean values of pre & post
orthodontically treated non-extraction cases, both of which
show minimal anterior retraction & space closure (less
than 2 mm) as well as minimal molar mesial movement &
anchorage loss.
From Table 5&Table 6, it is clearly evident that statistically
significant changes can be observed in the antero-posterior
dimensions in bicuspid extraction cases when compared to
non extraction cases. The above findings of the present
study were consistent with the results of Bailey et al. &
Almedia et al. [1][2]. Also, the present findings were
consistent with those of Boley & Sachdeva, where there
was a greater reduction in the arch length due to anterior
retraction as well as molar protraction [10].
Table 7&Table 8 show that the arch dimensional changes
in transverse dimension were highly statistically significant
between the pre & post treated models in extraction cases
(a mean of 3 mm intermolar width reduction & 0.5 mm
increase in intercanine width) and insignificant in nonextraction cases (0.2 - 0.3 mm reduction in the
corresponding values). Also, from Table 9, comparing
extraction and non-extraction intermolar width values, a
mean of 2.5mm of intermolar width reduction occurred in
extraction cases and less than 0.5 mm in non-extraction
cases showing statistically insignificant changes in nonextraction cases. In the intercanine region, a mean of 0.5
mm increase in the I.C.W value in extraction cases and less
than 0.2 mm increase in non-extraction cases showing
statistically insignificant change in both cases. Gain score
values from Table 9 indicate that there were significant
changes between pre & post treatment values for
measurements in the intermolar region and insignificant in
intercanine region. Thus, it can be inferred that transverse
arch dimensional values also showed significant changes in
extraction cases when compared to non-extraction cases.
All these findings were similar to the findings of the study
by Shearns & Woods (1999),where there was evidence of
greater reduction in the intermolar width after bicuspid
extractions[5]. However, our results did not correspond to
the findings of Boley & Sachdeva (2003) as well as that of
Giannely (2003) et al. with respect to the changes in the
arch width, since their results showed that maxillary arch
width remained unchanged after orthodontic treatment in
both extraction & non-extraction cases [10][11]. Minimal
increase in the intercanine width of 0.5 mm in extraction
groups from our study correspond to the previous study of
Giannely et al. [11] Therefore, from Table 1, Table
2&Table 7, it can be inferred that molar had moved
mesially into the narrower part of the upper arch thus
contributing to the reduction in the intermolar width and
contraction of the maxillary arch after orthodontic
treatment in bicuspid extraction cases.
To conclude, there were significant arch dimensional
changes in extraction cases & minimal arch dimensional
changes in non-extraction cases after orthodontic
treatment.
Significant antero-posterior tooth movements including
correction of proclination by retraction of anteriors & space
closure, mesial migration of molars into the narrower part
of the arch occurred in extraction cases. Also, there was a
considerable amount of anchorage loss in the posterior
segment in bicuspid extraction cases and minimal loss in
non-extraction cases. Transverse arch dimensional changes
include reduction in the intermolar width and contraction
of the maxillary arch as well as minimal change in the
intercanine width in extraction cases and minimal
transverse arch dimensional changes in non-extraction
cases after orthodontic treatment.
SUMMARY AND CONCLUSIONS
The present computer based AUTOCAD study reveals that
maximum antero-posterior arch dimensional changes can
be seen in orthodontically treated bicuspid extraction cases
and non-extraction cases show minimal changes in the
antero-posterior dimensions even after orthodontic
treatment. Significant amount of anchorage loss can be
seen in upper bicuspid extraction cases when compared to
non-extraction cases. Also, significant reduction in the
intermolar width and contraction of maxillary arch
occurred in upper bicuspid extraction cases because of the
mesial migration of the molars into the narrower part of the
upper arch as well as minimal changes in the intercanine
width in extraction cases and minimal transverse arch
dimensional changes in non-extraction cases after
orthodontic treatment.
REFERENCES
[1] Almedia, MA Phillips C Kula K Tulloch C et.alStability of the palatal rugae a landmark for analysis of
dental casts - Angle Ortho.1995:65 (1) 13-8, AJODO.1996; 110:191-6.
[2] Bailey LT, Esmail nejad, Almedia MA. Stability of the
palatal rugae as landmark for analysis of dental casts in
extraction and non extraction cases. Angle
Ortho.1996:66:73-8.
[3] Lysell L, Plica palatina and papilla incision in man - A
morphological and genetic study; Acta Odontolgica
Scandinavia I 3:Suppliment 18; 1.
[4] Thomas CJ & Kotze The palatal rugged pattern a new
classification. Journal of South African Dental
Association 38; 153-176,1983.
ABB 12|Volume 2|Issue 1|2015
7
Advances in Biology & BioMedicine
[5] Britanny Shearn & Michael Woods et.al - Occlusal and
Cephalometric analysis of lower first and second
premolar extraction effects. AJO-DO 1999; 115, 30513.
[6] Vanderlinden FP, Changes in posterior teeth in relation
points, AJO. 1978:74;14261.
[7] Savara BS. Application of photogrammetry for
quantitative study of tooth and face morphology. Am. J.
Phys. Anthropol. 1965;23:427–434.
[8] Brook &Pitts. Determination of tooth dimensions from
study casts using an image analysis system, Journal of
International Association of Dentistry for children
1983:14, 55-60.
[9] Peavy DC; Kendrick G'S, The effect of tooth movement
on palatal rugae - Journal of Prosthetic Dentistry
18:536-542,1967.
[10] Jimmy C Boley et.al-Long term stability of Class l
premolar extraction treatment AJO-DO 2003; 124; 27787.
[11] Anthony Gianelly-Arch width after extraction and non
extraction treatment-AJO-DO. 2003;123:25-8.
[12] John Walker -About AUTOCAD & it's accuracy.
Abstract from www.SOLAR.dwg1983.
8
ABB 12|Volume 2|Issue 1|2015