dr. ramesh g.c.-dissertation
TRANSCRIPT
Rajiv Gandhi University of Health Sciences, Karnataka, Bangalore.
CEPHALOMETRIC EVALUATION OF OVERBITE AND VERTICAL CHANGES FOLLOWING FIRST PREMOLAR EXTRACTION IN HIGH
ANGLE CASES – A RETROSPECTIVE STUDY
By
Dr. RAMESH G.C.
Dissertation Submitted to theRajiv Gandhi University of Health Sciences, Karnataka, Bangalore.
In Partial fulfillmentof the requirements for the degree of
MASTER OF DENTAL SURGERY
In Speciality of
ORTHODONTICS AND DENTOFACIAL ORTHOPEDICS
Under the Guidance of
Dr. ARUNKUMAR G.Associate Professor
Department of Orthodontics and Dentofacial OrthopedicsCollege of Dental Sciences,
Davangere.
2006- 2009
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ACKNOWLEDGEMENT
This Dissertation represents the assistance and efforts of many individuals, the
contributions of whom I acknowledge and to whom I give my thanks.
I bow my head to the supreme force THE ALMIGHTY, driving me to my
destinations, I thank them for having blessed me with his choicest blessings and
opening the doors of opportunity to this adobe of knowledge and having blessed me
with most loving family and teachers.
Words are inadequate to express my indebtedness and infinite respect for my
“Guru” and Guide, DR ARUN KUMAR G. Associate Professor, Department of
Orthodontics, College of Dental Sciences, Davangere. His unfailing willingness to
render help and loving guidance, coupled with his rich knowledge and keen interest
have been a constant source of inspiration and backbone of this study. Lucky are the
few who are privileged to work under him and imbibe priceless insights into life. I
find myself deeply indebted to him for teaching me the true values of life, imbibing in
me his virtues of hard work, truthfulness and love towards fellow human beings.
It is with utmost sincerity that I thank my beloved Professor and Head,
Dr.G Shivaprakash. A mere word of thanks is not sufficient to express his solid
support, inspiration and unswerving guidance, during my post graduation and in the
preparation of this dissertation. As his post graduate student, I have not only
inculcated knowledge in the art and science of orthodontics but also other human
qualities of life. His discipline, principles, scientific approach and logical explanation
to this art of orthodontics shall always be my guiding star.
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It is with utmost sincerity that I thank my beloved former Professor and Head,
Dr.Anmol S.Kalha. A mere word of thanks is not sufficient to express his solid
support, inspiration and unswerving guidance, during my post graduation and in the
preparation of this dissertation. To be his post graduate student definitely gives me
immense pleasure and honour.
The unflinching support and guidance I received from all the faculty members
during my post-graduate course leaves me with an overwhelming sense of profound
humbleness.
Let me at this juncture, pen down my deepest appreciation towards my
teachers, Dr.(Mrs) Mala Ram Manohar, Professor, Dr. Naveen Shamnur,
Associate Professor, Dr.Prabhuraj, Associate Professor, Dr.Umashankar, Reader,
Dr. Shashi Kumar, Asst. Professor, Dr. Anvar Latif, Asst. Professor, College of
Dental Sciences, Davangere for being my wheel of support and encouragement over
the last three years. It is with sincerest gratitude that I thank Dr. Litesh Singla &
Dr. Thomas, Assistant Professors, for giving valuable insights during the study and
during my post graduation course.
At this juncture my deepest gratitude goes to Sri. Shamanur
Shivashankarappa (Hon. Secretary), and Dr.V.V. Subba Reddy (Principal), for
providing me the kind of atmosphere, fully equipped with the near latest technologies.
This acknowledgement would be incomplete if I fail to mention
my Father Sri. CHANNAVEERAPPA, Mother Smt. GIRIJA, Brother in-laws,
DR A.R HANUMANTHAPPA and A.G NATRAJ GOWDA, and Sisters
Smt. SUDHA and Smt. REKHA and my Family Members. It is their love, prayers,
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many sacrifices and encouragement both morally and emotionally made it possible to
me what I am today.
It would be unfair on my part if I do not mention my batch mates,
Dr.Aravind, Dr. Naveen, Dr. Murtuza, Dr. Ankush and Dr. Divya, without them
this dissertation would have not been successful.
I would like to thank all my friends and especially juniors for their whole
hearted support in completion of my post graduate course.
With out the help of Mr. Sangam, our esteemed biostatistician, my work
would have gone unappreciated.
I also thank Mr.Surendra, Dyna Computers for organizing and neatly typing
this manuscript and Aruna Printers, for their services rendered.
A special word of thanks to the non teaching staff, especially sister Jesline,
Jagdish, Santosh and Neelappa, Geetha and Manjula for the help rendered
whenever required from them.
Place : Davangere.
Date : Dr. RAMESH G.C
VII
LIST OF ABBREVIATIONS USED
ANS Anterior nasal spine
BL1 Bodily movement of the mandibular incisors
FH Frankfort horizontal
Gn Gnathion
Go Gonion
HS Highly significant
I PM first premolar
II PM Second premolar
L1 Mandibular Central Incisor
L6 Mandibular first molar
LAFH Lower anterior face height
MNSK Mandibular skeletal change
MPA Mandibular plane angle
MXSK Maxillary skeletal change
N Nasion
NS Not significant
OP Occlusal plane
PEA Pre adjusted edgewise appliance
PFH Posterior face height
Pogv Pogonion vertical
S Sella
S Significant
Sv Sella vertical
TAFH Total anterior face height
TL1 Tipping movement of the mandibular incisors
TU1 Tipping movement of the maxillary incisors
U1 Maxillary Central Incisor
U6 Maxillary first molar
UAFH Upper anterior face height
ABSTRACT
VIII
Back ground & objectives : Orthodontists generally agree that non-extraction
treatment is associated with downward and backward rotation of the mandible and an
increase in the LAFH. They also agree that extraction line of treatment is associated
with upward and forward rotation of the mandible and decrease in the LAFH. The
intent of this cephalometric investigation was to examine the popular hypothesis,
(wedge hypothesis) that the vertical dimension collapses after first bicuspid
extraction. The present study was undertaken to evaluate the cephalometric overbite
and vertical changes following first premolar extraction in high angle cases.
Methods : A total of 25 adult patients having high mandibular plane angle i.e. Gogn –
SN more than or equal to 32 degrees having class I molar and canine relation were
included. Pre and post treatment lateral cephalograms were measured and compared
to analyze the cephalometric changes.
Results : There was a significant increase in the MPA. There was no significant
change in the pre and post treatment overbite, total anterior face height, lower anterior
face height and posterior face height.
Interpretation & Conclusion : The study concluded that, There was no increase in
the vertical facial dimension and overbite and no clinically significant increase in the
mandibular plane angle. However it should be interpreted with caution, given the
small sample size. The facial complex does increase in size with growth, but
mandibular plane while moving inferiorly, remain essentially parallel to its
pretreatment position, due to residual growth and treatment.
Key words: I premolar extraction; High angle; Wedge hypothesis; Lateral
cephalograms; Adult.
IX
TABLE OF CONTENTS
PAGE NO.
1. INTRODUCTION 01
2. OBJECTIVES 03
3. REVIEW OF LITERATURE 04
4. METHODOLOGY 24
5. RESULTS 38
6. DISCUSSION 44
7. CONCLUSION 50
8. SUMMARY 51
9. BIBLIOGRAPHY 52
10. ANNEXURES 58
X
LIST OF TABLES
SL.NO. TITLE PAGE NO.
Table 1DEFINITION OF CEPHALOMETRIC LANDMARKS AND MEASUREMENTS USED IN THE STUDY
25
Table 2 PRE AND POST TREATMENT COMPARISON OF ANGULAR MEASUREMENTS 39
Table 3 PRE AND POST TREATMENT COMPARISON OF LINEAR MEASUREMENTS 40
Table 4 PRE AND POST TREATMENT COMPARISON OF OVERBITE MEASUREMENTS 41
XI
LIST OF FIGURES
SL.NO. TITLE PAGE NO.
Fig. 1 ARMAMENTARIUM USED FOR TRACING RADIOGRAPHS 26
Fig. 2 OVERBITE MEASUREMENTS USED IN THE STUDY 28
Fig. 3 ANGULAR MEASUREMENTS USED IN THE STUDY 29
Fig. 4 LINEAR MEASUREMENT USED IN THE STUDY 30
Fig. 5 LAND MARKS USED TO EVALUATE MOLAR CHANGES 31
Fig. 6 PRE – TREATMENT EXTRA ORAL PHOTOGRAPHS 33
Fig. 7 PRE – TREATMENT INTRA ORAL PHOTOGRAPHS 33
Fig. 8 PRE – TREATMENT LATERAL CEPHALOGRAM 34
Fig. 9 MID – TREATMENT INTRA ORAL PHOTOGRAPHS 35
Fig. 10 POST – TREATMENT EXTRA ORAL PHOTOGRAPHS 36
Fig. 11 POST – TREATMENT INTRA ORAL PHOTOGRAPHS 36
Fig. 12 POST – TREATMENT LATERAL CEPHALOGRAM 37
XII
LIST OF GRAPHS
SL.NO. TITLE PAGE NO.
Graph I PRE – POST SIGNIFICANT ANGULAR MEASUREMENTS 42
Graph II PRE – POST INSIGNIFICANT ANGULAR MEASUREMENTS 42
Graph III PRE – POST INSIGNIFICANT LINEAR MEASUREMENTS 42
Graph IV PRE – POST ANTERIOR TOOTH MOVEMENTS 43
Graph V PRE – POST MOLAR MOVEMENTS 43
XIII
ANNEXURES
SL.NO. TITLE PAGE NO.
Master Chart 1 PRE – POST ANGULAR CEPHALOMETRIC MEASUREMENTS 57
Master Chart 2 PRE – POST LINEAR CEPHALOMETRIC MEASUREMENTS 58
Master Chart 3 PRE – POST OVERBITE CEPHALOMETRIC MEASUREMENTS 59
XIV
Introduction
INTRODUCTION
The extraction of permanent teeth has been a controversial topic throughout
Orthodontic history, beginning with the great extraction debate between Angle and
Calvin case1and continuing through Johnston’s comparison of extraction and non-
extraction outcomes in borderline cases.2 The “no extractions under any
circumstances”, Angle forces had been defeated by “extractions when necessary”,
Case forces on the strength of argument supported by the overwhelming
preponderance of countervailing scientific and clinical evidence.3
Schudy4-6 described facial types as “hypodivergent and hyperdivergent” and
recommended a nonextraction approach in treatment of hypodivergent facial types
and an extraction in hyperdivergent facial types “to close down the bite”. Sassouni
and Nanda7 concurred with this treatment sophy. Although it is difficult to argue
against extraction and non-extraction treatment, extraction of permanent teeth is still a
valuable arrow in the orthodontists quiver of options.1
The primary reason for extraction of permanent teeth are to correct the
discrepancy between tooth size and arch length to reduce bimaxillary protrusion. The
first clinical concern i.e. lack of contact between the anterior teeth, or openbite,
several authors have suggested that removing of permanent teeth from posterior
buccal segment with subsequent protraction to close the spaces corrects the open bite
by anti-clockwise rotation of mandible. This rationale for extraction is referred to as
“wedge hypothesis”.8
What role of extraction play in the cause or cure of TMJ disorders has been
actively debated in the dental literature. First premolar extractions are considered by
many to be an etiologic factor in TMJ disorders. These persons believe that extraction
1
Introduction
of premolars permits the posterior teeth to move forward resulting in a decrease in the
vertical dimension of occlusion. The mandible is then allowed to overclose, and the
muscles of mastication become foreshortened, as a result TMJ problems are likely to
occur. Although this theory is popular, no controlled study has published results
supporting this hypothesis. Another theory that has been proposed is that first
premolar extractions lead to over-retraction of anterior teeth, particularly the
maxillary anteriors. This over relocation of anterior teeth is thought to displace the
mandible and the condyle posteriorly resulting in TMJ disorders.9
Some disagreement exists concerning the effect of bicuspid extractions on the
vertical dimension. It has been suggested that orthodontic forward movement of the
posterior teeth after bicuspid extractions leads to a reduction in vertical dimension and
overclosure of the musculature. This is said to cause muscles to work inefficiently
and to result in pain and fatigue.10 Several authors suggests that it requires special
effort in addition to bicuspid extractions, to reduce the vertical dimension in high
mandibular plane angle (MPA) Grasis Pearson showed a mean decrease of 3.9o in
MPA following first bicuspid extraction, with vertical chin cups used before and
during orthodontic treatment.11
2
Objectives
OBJECTIVES
“The objective of the study is to evaluate vertical changes following first
premolar extraction in high angle cases”.
3
Review of Literature
REVIEW OF LITERATURE
An attempt has been made to analyze tooth movements occurring in cases
treated by the removal of four second and four first premolars. Also, to outline
primarily the indications for the use of second premolar extractions. There does not
appear to be any dominating evidence from which conclusions can be drawn;
however, a few generalizations may be permitted.
1. There seems to be an indication for mesial movement of molar teeth in certain
extraction cases if commonly accepted objectives are to be met consistently.
2. More mesial movement of molars (maintaining good inclinations) may be
accomplished through second bicuspid extraction than first bicuspid extraction
when that is the objective and the appliance is designed accordingly.
3. When arch length discrepancy is 7.5 millimeters or less and there is no
indication for incisor retraction, it may be advisable to consider second rather
than first premolars if extractions are to be performed.
4. There apparently is variability that exists in mesial movement and mesial drift
of molars in different individuals. Some factors involved may be:
a. Stage of dental development.
b. Number of unerupted molars.
c. Occlusion.
d. Degree of arch crowding.
e. Muscle balance.
Authors suggest, once extraction has been decided upon a further analysis as
to which teeth to remove should be considered, instead of accepting some may believe
to the only choice, namely, first premolars.12
4
Review of Literature
A study was conducted to evaluate overjet and overbite after orthodontic
treatment. Pretreatment, posttreatment and post- retention study models from fifty-
three orthodontically treated cases were examined at the State of New York
Department of Health, Bureau of Dental Health. Overbite and overjet data were
assembled, statistically analyzed, and tabulated for each of the different classes of
malocclusion leading to the following conclusions:
1. When total overbite correction and relapse were examined, the sample as a
whole showed continued posttreatment decrease in overbite. Both Class I and
Class III malocclusions exhibited this same pattern while Class II, Division 1
and Division 2 malocclusions showed, respectively, 30 per cent and 16 per
cent posttreatment increases in overbite.
2. The total overjet relapse in Class I cases was five per cent and in Class II,
Division 1 cases it was ten per cent. The whole sample showed a post-
treatment relapse in overjet of eight per cent.
3. The average relapse of those cases that did relapse was, at all times, less than
2.0 mm in all parameters measured.
4. The ability to predict relapse potential needs to be assessed further according
to more refined classifications of malocclusion, the types of treatment and the
characteristics of the patient.13
A study was carried out by utilizing standard diagnostic procedures in an
office, decisions were made on a number of extraction cases, selecting four first
premolars or four second premolars as the preferable teeth to remove. An effort was
made to determine whether there were some objective variables which were
significantly different for first premolar extraction cases and second premolar
5
Review of Literature
extraction cases. 43 patients were studied with an average age of 12 years, (range 8.3-
22.8 years) which includes 23 girls and 20 boys. Various measurements were used to
evaluate the changes in hard and soft tissue changes.
Authors concluded that, for the cephalometric indices used in this study and
the tooth-arch size discrepancy, there were no parameters which were significantly
different. When soft-tissue measurements were included however, and a discriminant
computer analysis completed, it was discovered that the nose tip, the chin, the
mandibular plane and the relation of the lips to the E-line were statistically significant
in determining whether the case was a first or second premolar extraction case. The
combination of lips to E-line and lower left central to APg (angle only) was helpful in
classifying second premolar cases. It must be emphasized that these parameters were
for the results of this sample only. Further, this entire study assumed that the
diagnostician has already decided that the case being evaluated is indeed a case
requiring sacrifice of dental units in both maxillary and mandibular arches, and that
the extraction site should be in the premolar area. In applying these formulae to a
specific patient they may serve as an aid to their diagnosis. The additional utilization
of the nose length, chin length and mandibular plane angle all used singly, help to
identify where the patient varies from the above standard formula, when the formula
does not seem clinically applicable.14
A study conducted by means of corrected tomography, the positions of the
condyles in patients who had undergone four-premolar extraction treatment (20
edgewise and 7 Begg) were compared with the condylar positions of patients who had
not yet received orthodontic treatment. No significant between-group differences in
condylar position were noted. In addition, the relationship between bite depth and
condylar position was examined and no significant correlation was found. Thus, as
6
Review of Literature
performed in this study, authors concluded that condylar position was unrelated to
extraction treatment and to bite depth.15
A cephalometric study investigates that the changes in the facial skeleton and
dento-alveolar structures which occur during orthodontic treatment of class II division
I malocclusion by extraction of four first premolars followed by fixed appliances. The
Begg and edgewise appliances are compared, and both are contrasted with a group of
untreated class II div I subjects. The main effects of treatment were in the dento-
alveolar structures, the change in the in the overall facial pattern small and largely due
to extrusion of molars during overbite reduction. Molar extrusion tended to interrupt
forward growth rotation of the mandible, temporarily making it more backwards in
direction and increasing lower anterior face height. An increase in the posterior lower
face height was also noted in the edgewise group. Whilst SNA, and therefore ANB,
reduced significantly during treatment, this was probably the result of palatal root
torque to the upper incisors. The Begg appliance was more successful than edgewise
in this respect.16
In a study, the effect of overjet and overbite correction in non-extraction and
extraction therapy in a class II malocclusion treated with edgewise appliance was
compared. The subjects were 20 children treated without extraction and 20 children
treated with extraction of four first premolars. During the post-treatment period
relapse of overjet and overbite occurred in both groups, however there was a
beneficial net effect of overjet and overbite correction in both groups with no
significant difference between the two groups. A study showed that mandibular
intercanine width space conditions in the lower jaw and mandibular incisor position
were important factors in treatment planning.17
7
Review of Literature
The orthodontist has been both accused of causing and complimented for
curing temporomandibular dysfunction. To better understand the origins of these
conflicting opinions, a review of the orthodontic and temporomandibular joint
journals was performed for articles published since 1966. A total of 91 publications
that discussed the relationship between orthodontics and temporomandibular disorders
was found, and these articles were divided in three categories: viewpoint publications,
case reports, and sample studies. Among the areas scrutinized in each category was
the method that has led to the diversity of viewpoints. From this analysis, the
following conclusions were drawn: (1) viewpoint publications and case reports were
excessively represented in comparison with the number of sample studies; (2)
viewpoint publications and case reports described a wide variety of conflicting
opinions on the relationship between orthodontics and temporomandibular disorders;
(3) unlike sample studies, viewpoint publications and case reports have little or no
value in assessment of the relationship between orthodontics and temporomandibular
disorders; (4) sample studies indicate that orthodontic treatment is not responsible for
creating temporomandibular disorders, regardless of the orthodontic technique; and
(5) sample studies indicate that orthodontic treatment is not specific or necessary to
cure signs and symptoms of temporomandibular dysfunction.4
A study was conducted to evaluate the condylar position following maxillary
first premolars extraction. Condylar position in 17 patients whose Class II treatment
(14 with edgewise appliances and 3 with Begg appliances) included extraction of the
maxillary first premolars and in 17 control patients was compared by means of
corrected tomography. The condyles in both groups were in an anterior position, and
there were no statistical differences between the groups. In addition, no statistical
correlation was found when the posttreatment bite depth, interincisal angle, and
8
Review of Literature
maxillary incisor inclination were correlated with condylar position. Thus, as
determined in this study, condylar position was unrelated to treatment, bite depth,
interincisal angle, and maxillary incisor inclination.19
It has been argued by a vocal coterie of disaffected dentists that premolar
extraction, incisor retraction, and "backward-pulling" mechanics conspire to
"distalize" the condyles and, pari passu, to produce craniomandibular dysfunction. 42
"edgewise" patients with Class II, Division 1 malocclusions, treated in conjunction
with the extraction of two maxillary first premolars. Regional and anterior cranial-
base cephalometric superimpositions were used to quantify the individual components
of the molar and overjet corrections, to measure both at the chin and condyles the
mandibular displacement seen during treatment, and to examine the extent to which
this displacement is related to the correction of maxillary incisor protrusion. Although
the present patients underwent marked upper incisor retraction (on average, about 5
mm), lip retraction was much less pronounced, and 70% of the sample showed a net
forward displacement of mandibular basal bone. Significantly, changes in condylar
position were not correlated with incisor retraction, as the "functional orthodontists"
would have it, but rather with the changes in the buccal occlusion and the growth of
the maxilla. Thus, 30% of the patients who showed evidence of distal displacement
were generally nongrowing patients who underwent more than average anchorage loss
in the mandible and less than average loss in the maxilla. Regardless of the direction
of basal displacement, however, condylar remodeling apparently served to stabilize
the spatial position of surface landmarks (e.g., condylion), an observation that
underscores the faulty of using any type of serial radiograph to assess changes in
condylar position in the growing, unimplanted patient.20
9
Review of Literature
A study was carried out evaluate the orthodontic risk factors for temporo-
mandibular disorders. There is Concern about claims that premolar extractions may
put patients at risk for temporomandibular disorders (TMD). They have reported first
findings from a longitudinal study of orthodontic patients begun in 1983. By using the
methods of Helkimo, TMD data before initiation of orthodontic treatment, between 0
and 12 months after debanding, and 12 to 24 months after debanding. Analyses
related Helkimo scores with premolar extractions in 65 patients for whom orthodontic
treatment had been completed. Twenty-six patients were treated without premolar
extractions, 25 had four premolars extracted, and 14 had two upper premolars
extracted. Tests for significance of differences between mean Helkimo scores were
conducted for the nonextraction group compared with the extraction groups, and
between pretreatment and posttreatment Helkimo scores for each group. Results
included: (1) no significant intergroup differences between mean pretreatment or
posttreatment scores, and (2) small but statistically significant (p < 0.05) differences
(in the direction of improvement) between mean pretreatment and posttreatment
scores for both the nonextraction group and for the four premolar extraction group.21
Authors conducted a study to evaluate the effects of extraction and
nonextraction orthodontic treatment mechanics on patients with dolichofacial and
brachyfacial growth patterns between one and two standard deviations were studied.
Groups underwent treatment of either nonextraction or extraction of four premolars
with the appropriate mechanics for the facial type. Changes in the facial axis and
correlation between maxillary molar movement and facial axis change were
measured. A positive correlation was found between the amount of anteroposterior
movement of the upper molar and change in the facial axis in brachyfacial and
dolichofacial patients undergoing nonextraction treatment. A weak correlation was
10
Review of Literature
found in the extraction treatment groups. No statistically significant difference was
found in the facial axis change among any of the groups studied, regardless of facial
type or plan of treatment. There were indications of a more severe opening of the
facial axis (Ba-Na plane to constructed gnathion) with greater degrees of maxillary
molar distal movement in both facial patterns studied.22
A study was carried out evaluate the effects of extraction versus non-
extraction orthodontic treatment on the growth of lower anterior face height. The
effect of Orthodontic treatment on the lower anterior face height (ANS – Me) is of
fundamental importance to Orthodontist. However, the choice between the two
methods of treatment, extraction versus non-extraction, is not clear cut. It is believed
that the extraction method decreases ANS – Me, whereas non- extraction method
results in increase in ANS-Me. This study examined both the methods on 174 subjects
which were equally divided into class I and class II malocclusions. In addition to
growth and treatment duration, other factors like the effects of treatment choice and
treatment mechanics were considered. The results showed that non-extraction
treatment in class I and class II subjects is associated with significant increase in
lower anterior face height. However extraction treatment is not associated with any
significant change in ANS-Me.23
A long term study was done to compare the outcomes in clear cut extraction
and non-extraction class II patients. Discriminant analysis was used to assess the
anatomical basis of the extraction/nonextraction decision in 238 former Saint Louis
University Class II edgewise patients. The resulting discriminant scores (based on six
measures of protrusion and crowding) were used to divide this parent sample into
three prognostic subgroups: clear-cut extraction, clear-cut nonextraction, and a
borderline stratum containing both extraction and nonextraction patients. The "clear-
11
Review of Literature
cut" patients—those at the tails of the distribution—were then contacted and asked to
return for follow-up records (cephalograms, models, clinical examination); in the end,
62 (33 extraction and 29 nonextraction) were recalled. The average post-treatment
interval was about 15 years. Premolar extraction produced a significantly greater
reduction in hard-and soft-tissue protrusion. During the post-treatment period,
however, both groups underwent essentially the same change: decreased profile
convexity and a pattern of dental change/relapse that was correlated with antero-
posterior mandibular displacement. Because of their greater initial crowding and
protrusion, the various effects summed to make the extraction patients significantly
more protrusive at recall. Both treatment produced mesial mandibular displacement,
extraction significantly greater than non-extraction, however at recall both groups did
not differ with respect to the signs and symptoms of dysfunction. Authors concluded
that, this study fail to support the common influential belief that premolar extraction
frequently causes “dished in” profiles, “distalized” mandibles, and ultimately
craniomandibular dysfunction.24
A study was conducted to evaluate the effects of first bicuspid extractions on
facial height in high angle cases. Mesial molar movement is expected in first bicuspid
extraction cases and accounts for the belief that facial height should decrease. This
study examined 16 boys and 21 girls, with an average age of 11 years 10 months, at
the outset of treatment. Results showed that 3.2 mm of upper molar extrusion and 2.2
mm of lower molar extrusion. As much as 1.9 mm of vertical movement of molar and
1.6 mm of that mandibular molar can be attributed to growth. This study indicate that
the occlusal movement of the posterior teeth tends to keep the occlusal movement of
the posterior teeth tends to keep pace with the increase in anterior face height, thus
maintaining the MPA and nullifying the bite closing effect of posterior protraction.
12
Review of Literature
The facial complex does increase in size with growth, but the Gogn plane, while
moving inferiorly, remains essentially parallel to its pretreatment position, due to both
the growth and treatment.10
A study was conducted to determine the vertical changes following first
premolar extraction. Orthodontic treatment involving the extraction of first premolars
has been implicated in the dental literature as an etiologic factor in the development of
TMJ disorders. Authors have proposed that the extraction of first premolars causes a
decrease in the vertical dimension of occlusion. The purpose of this study was to
investigate the validity of this claim. Records of 45 class I, non-extraction cases and
38 class I, first premolar extraction cases were obtained. The pre-treatment and post-
treatment cephalograms were digitized, and several cephalometric variables were
examined to evaluate the vertical changes occurring as a result of orthodontic
treatment. Statistical analysis of the data revealed no significant differences between
the vertical changes occurring in the extraction and non-extraction groups. On
average, orthodontic treatment in both groups produced an increase in the
cephalometric vertical dimensions that were examined.9
Extraction has been a controversial subject for as long as the specialty of
orthodontics has existed. Some authors believe that the extraction of premolars leads
to temporomandibular disorders. This occurs, they say, because the vertical dimension
collapses. Concomitantly, over-retraction and retroclination of the incisors cause the
facial profile to flatten, bring about premature anterior contacts, and distally displace
the mandible and mandibular condyle. Numerous correlation studies in the dental
literature do not support this contention. There appears to be no higher incidence of
temporomandibular disorders in patients treated with the extraction of premolars than
in nontreated patients or those treated without extractions. Analysis of premolar
13
Review of Literature
extraction cases reveals that there is no collapse of the vertical dimension; on the
contrary, the vertical dimension is either maintained or slightly opened. Similarly,
there is no evidence that premolar extraction causes undesirable flattening of the
facial profile. The facial profile established during treatment is primarily the result of
diagnosis and treatment mechanics. Excessive anterior interferences resulting in
possible posterior condyle displacement are the result of treatment mechanics. When
arches are leveled properly and space closure and overjet reduction are adequately
controlled, there is no reason that such interferences should occur. Thus study reveals
little support for the claim that premolar extraction treatment leads to
temporomandibular disorders.25
A study was done to evaluate the effects of different growth pattern and
treatment type factors on craniofacial structures in cases treated with different fixed
mechanics and premolar extractions. A total of 41 cases with a mean chronologic age
of 14 years 7 months and skeletal age of 14 years 6 months was included in the study.
These cases were treated with fixed edgewise mechanics and with extraction of four
first premolars. The growth pattern factor was assessed in two levels as
mesiodivergent and hyperdivergent, and the treatment factor was assessed as with and
without headgear. The results in the assessment of differences between the two types
of growth patterns at the end of treatment, the changes in N-ANS and N-Me were
found to be statistically significant. Interaction was found to be non-significant for all
measurements. It was observed that treatment with fixed appliances and premolar
extractions does not change significantly the growth pattern.26
The study was conducted by authors to evaluate the vertical changes
occurring in Class I patients treated orthodontically with first premolar extraction and
to compare these changes with those occurring in Class I patients treated
14
Review of Literature
orthodontically without extractions. Records of 40 Class I nonextraction cases (24
girls, 16 boys) and 40 Class I maxillary and mandibular first premolar extraction cases
(23 girls, 17 boys) were obtained. The pretreatment and posttreatment cephalograms
were digitized, and 6 linear and 8 angular cephalometric measurements were selected
to evaluate vertical changes. Evaluation of the treatment results of the extraction and
nonextraction cases showed that the vertical changes occurring after the extraction of
maxillary and mandibular first premolars were not different than those occurring in
the nonextraction cases. Authors concluded that this study disproves the hypothesis
that the extraction of premolars leads to a loss of vertical dimension which in turn
leads to TMJ disorders.27
Authors conducted a cephalometric study to evaluate an early nonextraction
treatment approach for patients with severe vertical skeletal dysplasia and maxillary
transverse constriction. Thirty-eight patients, 8.2 years (± 1.2 years) of age, were
treated for 1.3 years (± 0.3 years) with lip seal exercises, a bonded palatal expander
appliance, and a banded lower Crozat/lip bumper. The bonded palatal expander
functioned as a posterior bite-block and was fixed in place throughout treatment.
Patients with poor masticatory muscle force (79%) wore a high-pull chincup 12 to 14
hours per day. A control group was matched for age, sex, and mandibular plane angle.
Treatment changes for chincup and other patients were not significantly different.
Overall, treatment significantly enhanced condylar growth, altered it to a more
anterosuperior direction, and produced "true" forward mandibular rotation 27 times
greater than control values. Posterior facial height increased significantly more in
patients than in controls, and the maxillary molars showed relative intrusion. In
treated patients, articular angle increased, gonial angle decreased, and the chin moved
anteriorly twice as much as in controls. Treatment also led to increased overbite and
15
Review of Literature
decreased overjet. Maxillary and mandibular expansion did not cause the mandibular
plane angle to increase. The 16 patients with openbite malocciusions exhibited a 2.7
mm increase in overbite and inhibition of growth in anterior lower facial height. The
aggregate of individual changes demonstrates a net improvement, indicating this
treatment approach may be suited for hyperdivergent patients with skeletal
discrepancies in all 3 planes of space.28
A study was carried out to evaluate the vertical facial changes in adult
orthodontic patients and to evaluate the stability of these changes. Thirty three
patients (8 males and 25 females) were examined. The patients had been treated fixed
edgewise appliance mechanics and exhibited atleast 1.0º of clockwise rotation of the
mandible during treatment. Mandibular rotation was determined by the angular
change in the Y-axis to the Frankfort horizontal plane. Twelve angular and 14 linear
skeletal and dental measurements and three skeletal ratios were derived from
pretreatment (T1), posttreatment (T2), and postretention (T3) cephalometric
radiographs. Twenty-five percent of the opening rotation of the mandible recovered
during the posttreatment period., resulting in a significant overall rotation that was
maintained. Both treatment and posttreatment changes in the Y-axis angle. Stepwise
regression analysis of pretreatment variables and treatment changes failed to predict
the behavior of the Y-axis angle change.29
A study was carried out to evaluate the effects of orthodontic treatment on the
soft tissue facial profile of patients with long and short facial types. Orthodontic
treatment records of 99 white long-faced and short-faced patients were analyzed to
determine the effects of edgewise orthodontic treatment over an average period of
2.16 ± 0.32 years. The average ages at the initiation and conclusion of treatment were
13.40 ± > 40 years and 15.61 ± 0.29 years, respectively. A significant finding in this
16
Review of Literature
study was the large variability in set tissue response to tooth movement. This
variability was due to a wide dispersion of individual results between upper and lower
lip change to maxillary and mandibular incisor movement anteriorly or posteriorly.
Because of this soft tissue variability among individuals, definite differences between
the long-faced and short-faced types could not be identified, nor was it possible to
establish definite ratios for change in lip response to incisor movements.30
The study was conducted using lateral cephalometric radiographs taken before
and after treatment. fifteen patients who had an anterior open bite (AOB) only were
treated with first premolar extractions (Group E4). Seventeen patients with an AOB
extending to the posterior teeth were grouped according to the extractions: extraction
of second premolars (Group E5) and first molar (Group E6). Cephalometric data were
analysed according to the 'two factor experiment with a repeated measure on one
factor' model. The treatment group factor had three levels, E4, E5, and E6, and the
time factor two levels, pre- and post-treatment. The differences between the pre- and
post-treatment periods were statistically significant for all the cephalometric variables
(P< 0.001, P< 0.0001), except for ANS-Me/ Na-Me, The time and group interaction
were found to be statistically significant for the variables where the time factor is
important, such as SN-GoGn angle, SGn-NBa angle, ANS-Me dimension, Na Me
dimension, forward movement of the maxillary and mandibular molars, and the
distance to the mandibular plane of the lower molars. The severity of vertical
dysplasia did not change in group E4. Generally, however, within the appropriate
indications, extraction of the second premolars or the first molars led to a closing
rotation of the mandible in subjects with a skeletal AOB extending to the posterior
teeth.31
17
Review of Literature
A study was carried out to evaluate the effects of bilateral upper premolar
extraction on mandibular growth. Twenty-six subjects (8 males and 18 females) in
maximum pubertal growth with an angle class II molar relationship, normal to mild
overjet increase, mild or lower arch length discrepancy and no severe skeletal
discrepancy were divided into two groups equal in number and gender, as extraction
and control groups. The median chronological age was 11.2 years in the extraction
group 12.6 years in controls. The subjects were observed for a median period 1.1
years in the extraction group after bilateral extraction of the upper premolars and 1.2
years in the controls until termination of pubertal growth (DP3u) without any
orthodontic treatment. Twenty nine linear and angular measurements were made on
52 lateral cephalograms and hand-wrist radiographs taken before and after the study
period. The increase in SNB measured on the total superimposition was significantly
greater in the controls than in the extraction group. In addition, anterior mandibular
counterclockwise rotation was significantly in the control group. Thus, it might be
suggested that bilateral upper premolar extractions might affect the mandibular
rotation tendency.32
A study was conducted to evaluate the effects on vertical dimension following
first or second premolar extraction. Objective of the study is, mesial movement of the
molars to reduce the “wedge effect” and decrease facial vertical dimension valid. This
study compares the mesial movement of Molars and changes in the FVD between P1
and P2 groups in class I malocclusion with hyperdivergent facial pattern. 27 cases
(P1-group1) with maxillary and mandibular first premolar extraction and 27 cases
(P2-group 2) with second premolar extractions were compared. Results showed that
group 2 showed more mesial movement of the maxillary and mandibular molars and
less retraction of maxillary and mandibular incisors than group 1. Both the groups
18
Review of Literature
showed increased anterior facial height, but there were no statistically significant
differences in angular and proportional measurements between pre and post treatment.
There were no significant differences in the amount of FVD between group 1 and 2
except in the maxillomandibular plane angle and SN to palatal plane angle. These
results suggest that there is no decrease in FVD regardless of the maxillary and
mandibular first or second premolar extraction. Therefore authors conclude, the
hypothesis that second premolar extraction in hyperdivergent facial types will result
in mesial molar movement and decrease FVD by reducing “wedge effect” is invalid.33
A retrospective, longitudinal, cephalometric study was carried out to
investigate the influence of extraction and non-extraction orthodontic treatment on the
facial height of Japanese – Brazilians with class I and class II division I malocclusion.
Sample included 59 mesocephalic patients distributed into 4 groups. Group 1: class I
patients treated with 4 first premolar extractions, Group 2: class I patients treated with
non-extraction. Group 3: class II division I patients treated with 4 first premolar
extractions, Group 4: class II division I patients treated with non-extraction. The
overall initial mean age of the groups was 12.14 years, and all cases were treated with
standard edgewise appliances for a mean period of 2.49 years. The pre-treatment and
post-treatment stage comparison and the intergroup comparison of the treatment
changes were conducted between extraction and non-extraction groups in the class I
and class II malocclusions. Results showed that changes in the absolute magnitude of
posterior and anterior facial heights and in the ratios of lower posterior facial heights/
lower anterior face height and lower anterior face height/total anterior face height
were similar in extraction and non-extraction treatment in both class I and class II
malocclusions. Authors concluded that facial height were similar between extraction
and non-extraction treatment in both class I and class II malocclusios34
19
Review of Literature
A study was carried out to evaluate the outcome of standard edgewise
orthodontic treatment with extraction of 4 first molars (6xT group) or Tweed
edgewise treatment with extraction of 4 first premolars (4xT group). A cephalometric
analysis that isolated tipping and bodily movements of the maxillary and mandibular
incisors and measured vertical changes in the anterior region of the maxilla and
mandible used. Thirty subjects treated 10 practioners comprised the 6xT group,
whereas 31 subjects treated in the case western university orthodontic clinic were
used in the 4xT group. Control groups (6xC) and 4xC) were selected from untreated
subjects enrolled in the Bolton-Brush growth study and were matched on age and
gender. Data were collected before (T1) and after (T2) treatment. Results showed no
statistically significant changes between 6xT and 6xC for any of the variables studied.
An increase in overbite of 2.1 mm in the 6xT group was small but clinically
significant changes in both tipping and extrusion of maxillary and mandibular
incisors. In the 4xT group, statistically and clinically significant changes were
observed for intrusion of the maxillary and mandibular incisors, resulting in a 4.1 mm
decrease in overbite. Importantly, both the 6xT and 4xT groups showed no increase in
mandibular vertical height during treatment. Authors concluded that both treatment
strategies showed good control of vertical mandibular growth. Bodily intrusion of
the anterior teeth was the main contributor to correction of deep overbite in the Tweed
edgewise sample.1
A study was conducted to evaluate the vertical changes in class II division 1
malocclusion after premolar extractions. 26 cases each in two groups with 16 boys
and 10 girls, group 1 treated with mandibular first premolar extractions (age: 13.2 ±
1.5years) and group 2 treated with mandibular second premolar extraction. The two
groups were matched by sex, age, (with in six months) and facial divergence
20
Review of Literature
measured by maxillary-mandibular plane angle and ratio of posterior face height to
total anterior face height. Results showed, second premolar extraction was associated
with more mesial movement of the mandibular molars, but there was no significant
difference in vertical facial growth between the two groups. There was no significant
change in mandibular plane angle and MM angle in both the groups. Authors
concluded that this study do not support the hypothesis, that mandibular premolar
extraction is associated with mandibular overclosure or reduction in the vertical
dimension, or both, in subjects with class II division I malocclusion.35
Authors conducted a cephalometric study was to investigate vertical
dentoalveolar compensation in untreated adults with excessive (long-face) and
deficient (short-face) lower anterior face heights. Vertical and sagittal base
relationships, vertical dentoalveolar dimension in the anterior region of the jaws,
incisor inclination, overbite, and overjet were assessed in 112 short-face and 95 long-
face subjects. The contribution of skeletal and dentoalveolar components to achieve a
normal overbite was assessed by means of regression analysis. For the 2 most
important independent variables of the regression equation, the values were calculated
that would render an overbite of 2 mm. It was subsequently investigated whether the
calculated value fell within the range of the sample. The results showed that, in long-
face subjects, overbite was mainly related to lower anterior face height; in short-face
subjects, it was mainly related to mandibular anterior alveolar and basal heights.
Dentoalveolar compensation occurred in both groups mainly by adaptations in
mandibular incisor alveolar and basal heights. Molar height was unrelated to overbite.
Cutoff values for achieving a positive overbite were calculated for lower face height
and mandibular incisor alveolar and basal heights. Authors concluded that, the lower
face height mainly determines the overbite in long-face subjects, while in short-face
21
Review of Literature
subjects, lower dentoalveolar morphology influences overbite. Lower dentoalveolar
compensation can maintain a normal overbite in long-face subjects to a limited
extent.36
A study was carried out by authors to determine, if appliance induced increase
in the in the heights of upper and lower molars in girls with class II division I
malocclusion, and the consequential increase the height of the face are maintained.
Ten angles and ten linear measurements were measured on lateral cephalograms of 11
year old girls (8.5-14 years) with treated (N =9) and untreated (N=8) class II division
I malocclusion. The intervals between initial and recall records were, on average, 12
years (7.6-15.5 years) for the girls in the treatment group, and 8 years (4-13 years) for
the girls untreated/control group. In the treatment group 8 girls were treated with
Begg appliance and class II elastics. Results showed that upper and lower molar
heights in both the groups increased significantly, between the initial and recall visits.
There were no significant differences between the molar heights in the groups at the
start or recall visits. AFH also increased significantly in both groups between initial
and recall visits. At recall, AFH in the treatment group was significantly greater than
AFH in the control group. This finding is attributed to similar sized differences
between the groups at the start, to the longer period between the initial and longer
period in the treatment group and to lesser variation in the both groups at recall. In
both groups, posterior face height increased significantly between the initial and recall
stages. At the conclusion of the study there were no statistically significant
differences between the treated and control groups in either overjet or the inclination
of upper incisors. Relapse of upper incisors in the treatment group and retroclination
of upper incisors in the control group reduced the initial differences between the
groups. These changes are attributed to altered lip posture and increased lip pressure
22
Review of Literature
in adolescence. At recall, angles SNA and SNB were significantly smaller in the
treatment group. Authors concluded that heights of the upper and lower molars and
the face increased in both groups. Orthodontic treatment effect have no lasting effect
on either the height of the face or the heights of the molars in girls with class II
division I malocclusion.37
There is disagreement concerning the effect of premolar extractions on the
dentofacial vertical dimension. It has been suggested that orthodontic forward
movement of the posterior teeth after first premolar extraction leads to reduction in
vertical dimension. The purpose of this study was to examine cephalometrically the
dentofacial vertical changes in Class I Indian subjects treated with and without
extractions. The extraction group included 31 normodivergent patients (26 female, 5
male; pretreatment age, 17.19 ± 3.89 years) with maxillary and mandibular first
premolar extractions. The nonextraction group included 29 patients (18 female. 11
male; pretreatment age, 18.48 to 3.61 years). A coordinate system with the Frankfort
horizontal plane and a mandibular fiduciary line was used for the cephalometric
calibration. To determine vertical dimension changes due to treatment and to compare
differences between the 2 groups, paired and unpaired t tests were performed,
respectively. Results showed that both groups had increases in linear vertical
dimensions (P <0.05), but the change was comparatively greater in the extraction
group (P <0.05). Mesial movement of the maxillary and mandibular posterior teeth
was coincidental with the extrusion to such an extent that it increased the vertical
dimension, although the mandibular plane angle remained unchanged during
treatment. Authors concluded that extraction of teeth only to increase the overbite or
decrease the mandibular plane angle might not be justified.38
23
Methodology
METHODOLOGY
Materials and Method :
The present retrospective study was designed to evaluate the overbite and
vertical changes following first premolar extraction in high angle cases, who have
been orthodontically treated with pre-adjusted Edgewise appliances (0.022 slot, MBT)
in the Department of Orthodontics and Dentofacial Orthopaedics, College of Dental
Sciences, Davangere.
Sample Size :
Twenty five adult patients were randomly selected from the pool of completed
cases with pre and post treatment records in the Department of Orthodontics and
Dentofacial Orthopedics. All 25 cases were treated with consistent biomechanical
principles, transpalatal arch / Nance palatal arch were used for anchorage. Sample
included 12 boys, of age ranging from 17.3 years to 21.6 years (Average 18.9 years)
and 13 girls of age ranging from 17.1 years to 20.6 years (Average 18.6 years).
Sample Selection :
The sample eligible for the study was selected on the basis of the following
criteria.
Inclusion Criteria :
Cases having high mandibular plane angle, that is GoGn-Sn greater than or
equal to 32o (Steiners analysis).
Cases treated with PEA with all first bicuspids extractions
Cases having Class I molar relation bilaterally.
Exclusion Criteria :
Cases with Class II and Class III molar relationship.
24
Methodology
Cases treated with surgical orthodontics.
Armamentarium Used in the Study (Fig.1):
0.3 mm pencil
0.3mm lead acetate tracing sheets
Set of proctractors
X – ray View box
Eraser
TABLE – 1 : DEFINITIONS OF CEPHALOMETRIC LANDMARKS
MXSK The distance between the intersection of the vertical horizontal reference liens to ANS.
BU1 The distance between ANS and CRU1.
TL1 The distance between CRU1 and IEU1.
BL1 The distance between CRLI and IEL1
MNSK Distance between CRLI and Me.
MPA It is the angle formed between Gogn - SN
UAFH It is the linear distance from N to ANS.
TAFH It is the linear distance t from N to Me
LAFH It is the linear distance from ANS to Me
PFH It is the linear distance from S to Go
Sv Perpendicular to FH plane from sella
Pogv Perpendicular to FH plane from pogonion
Gogn – FH It is the angular measurement between Gogn – FH
Gogn – PP It is the angular measurement between Gogn – PP
Go - OP It is the angular measurement between Gogn – OP
SN - PP It is the angular measurement between SN – PP
SN - OP It is the angular measurement between SN – OP
25
Methodology
26
Methodology
The analysis compares radiographs with judicial horizontal and vertical
reference lines, at the T1 tracing horizontal drawn parallel to the FH and a
perpendicular line was drawn to establish the vertical reference used. The T2 tracing
was superimposed on the T1 tracing by using cranial base landmarks and both the
horizontal and vertical fudicial lines were carried through the T2 tracing. Six
landmarks, Anterior Nasal Spine (ANS), Centre of Rotation of the maxillary and
mandibular central incisors (CRU1 and CRL1), incisal edges of the maxillary and
mandibular central incisors (IEUI) and (IELI) and menton (Me) were identified on
each cephalogram and projected on to the vertical reference line, keeping the
landmark location parallel to the horizontal reference line. This procedure resulted in
six linear variables.
1) Maxillary skeletal change (MXSK): - The distance between the intersection
of the vertical horizontal reference lines to ANS.
2) Bodily movement of the maxillary incisors (BU1): - the distance between
ANS and CRU1.
3) Tipping movement of the maxillary incisors (TU1): – the distance between
CRU1 and IEU1.
4) Tipping movement of the mandibular incisors (TL1): – the distance
between CRLI and IEL1.
5) Bodily movement of the mandibular incisors (BL1): – distance between
CRLI and Me.
6) Mandibular skeletal change (MNSK): - the distance between ANS and Me
projected onto the vertical reference line.
27
Methodology
Fig. 2 : Schematic Diagram showing Overbite changes
The net change in these variables were used to compute changes in the
dependent variables – ‘overbite’ by using the following equation.1
AOB = ∆ MNSK + ∆ BUI + ∆ TUI + ∆ BLI + ∆ TLI
Where ∆ - Net change
Tracing 2 minus tracing 1, gives the post treatment changes in overbite.
Following, angular and linear measurements were selected to evaluate
vertical dimensional changes.7
28
Methodology
Angular Measurements :
1) Go Gn to SN
2) Go Gn to FH
3) Go Gn to PP
4) Go Gn to Occlusal plane
5) SN to PP
6) SN to FH
7) U1 to SN
8) L1 to Go Gn
9) IMPA
10) Y-Axis
Po Or
S
Cd
AANS
Me
N
PgGn
Go
Fig. 3 : Schematic diagram showing angular land marks used in the study
29
Methodology
Linear Measurements :
1) UAFH – N to ANS
2) Post FH – Se to Go
3) AFH – N to ANS
4) LAFH – ANS to Me
5) Anteroposterior face height ratio = X 100 = _ _ _ %
6) Sv – U6
7) Pog – L6
8) FH – U6
9) FH – L6
Fig. 4 : Schematic diagram showing linear land marks used in the study
Po Or
S
Cd
Me
ANSA
Go
N
30
Fig. 5 : Schematic diagram showing land marks used to evaluate molar changes in the study
Po Or
S
Cd
AANS
Me
N
PgGn
Go
STATISTICAL ANALYSIS :
Results are expressed as mean SD paired t-test was used to analyse post-
treatment changes in cephalometric evaluation.
The results were also ascertained by non-parameteric Wilcoxon’s test
whenever the measurements were presumed to be non-normally distributed. All the
analysis were done using SPSS Software (Version 13), USA.
P-value of 0.05 or less was considered for statistical significance.
Formulae Used for Analysis:
∑ xi Mean, x = ------- i = 1, 2… n
n
∑ (xi – x)2 Standard deviation, SD = -------------
n – 1
SD
Standard Error, SE = ---------
Mean of the differences Paired t test, t = ------------------------------------------- Standard error of the differences
= -------------
sd /
Wilcoxon’s Signed Rank Test (Alternative to Paired t-test)
Pre-post differences are found for each case and ranks are assigned to the
differences. Sum of the negative and positive ranks are found separately.
Least of these two sums (-ve +ve) is compared with table value for
significance.
Results
RESULTS
There was statistically significant change in the MPA (Gogn-SN) but the mean
difference in the change -0.5 mm (Table I) suggests that the change is clinically
insignificant.
There was statistically significant change in the U1 to SN, L1 to Gogn, BUI
and BLI (Table II and Table IV) suggesting that, the extraction space was closed by
retraction of the anteriors. The mean change in the U1 to SN and LI to Gogn is 10.8
and 7.9 degrees respectively. The mean change in the BU1 and BL1 is -2.4 and 2.3
mm respectively.
There was significant change in the sella vertical to mesiobuccal cusp tip of
maxillary first molar and pogonion vertical to mesiobuccal cusp tip of mandibular
first molar (Table IV) suggests that there was mesial movement of the upper and
lower molars. The average mesial movements of maxillary and mandibular molars is -
2.3 and -2.2 respectively.
There was a statistically significant change in the FH plane to mesiobuccal
cusp tip of maxillary first molar and FH plane to mesiobuccal cusp tip of mandibular
first molar, suggesting that there was extrusion of molars in maxillary by -2.2 mm and
in mandible by 1.2 mm.
There was a slight changes in the certain parameters shown in the Table II III
V IV. Although there was a slight change, the difference in the changes were very
less and statistically insignificant.
Results
TABLE – II
PRE AND POST TREATMENT ANGULAR MEASUREMENTS
Parameters Pre Post Difference t-Value p-Value
Gogn-SNMean 33.8 34.3 -0.5
2.3 0.03, SSD 1.2 1.3 1
Gogn-FHMean 27.04 27.04 0
0 1.00, NSSD 2 1.1 2.4
Gogn-PPMean 25.4 25.7 -0.3
-1.77 0.09, NSSD 1.6 1.1 0.8
Gogn-OPMean 16 16.04 0.04
-1 0.92, NSSD 0.9 1.6 2.1
SN-PPMean 10 10.3 -0.3
-1.16 0.26, NSSD 1.1 1.4 1.2
SN-FHMean 9.8 9.8 0
0 1.00, NSSD 0.8 0.9 0.7
UI-SNMean 116.8 105.9 10.8
29.08 <0.001, HSSD 2.3 1.2 1.9
LI-GognMean 102 94 7.9
26.94 <0.001, HSSD 3 2.5 1.5
U-GonialMean 53.6 53.6 0
-0.44 0.66, NSSD 1 1 0.5
L-GonialMean 76.2 76.3 -0.04
-0.09 0.93, NSSD 1.9 2 2.3
Y-ANSMean 67.2 67.4 -0.2
-1.04 0.31, NSSD 1.3 1.6 1
Results
TABLE – III
PRE AND POST TREATMENT VALUES OF LINEAR MEASUREMENTS
Parameters Pre Post Difference t-value p-value
N-MeMean 125.1 126 -0.12
0.37 0.72, NSSD 3.1 2.8 1.6
N-ANSMean 52 52.1 -0.1
-0.62 0.54, NSSD 1.6 1.5 0.6
ANS-MeMean 70.1 71.1 -0.04
-0.17 0.87, NSSD 3.6 3.3 1.2
Se-GoMean 72.4 72.2 0.2
1.41 0.17, NSSD 3.3 3.3 0.7
APF Ht Ratio
Mean 59.64 59.71 0.020.2 0.84, NS
SD 0.6 0.8 0.6
Results
TABLE – IV
OVERBITE AND VERTICAL CHANGES OF DENTITION
Parameters Pre Post Difference t-value p-value
MXSISMean 23.4 23.9 -0.5
-1.81 0.08, NSSD 1.7 1.6 1.3
BU1Mean 16.15 18.9 -2.4
-11.52 <0.001, HSSD 1 1 1
TU1Mean 19.4 20.6 -1.2
-5.79 <0.05, SSD 1.1 1.1 1
BL1Mean 25.7 23.4 2.3
7.77 <0.001, HSSD 1.7 1.1 1.5
TL1Mean 13.6 12.6 1.1
4.22 <0.05, SSD 1.2 1.1 1.3
MNS1sMean 73.9 73.8 0.1
0.25 0.80, NSSD 1.2 1.2 1.6
OBMean 150.5 150.2 0.2
0.79 0.44, NSSD 2.4 1.8 1.5
Sv-U6Mean 40 42.3 -2.3
-25.2 <0.05, SSD 0.9 0.9 0.5
Pog-L6Mean -20 -17.8 -2.2
-19.58 <0.05, SSD 1 1 0.6
FH-U6Mean 46.4 48.6 -2.2
-24.39 <0.05, SSD 1.7 1.5 0.5
FH-L6Mean 47.5 46.3 1.2
4.77 <0.05, SSD 1.6 1.6 1.3
Results
Graph I : Pre-Post Significant Angular Measurements
0
20
40
60
80
100
120
Deg
rees
Gogn-SN U1-SN L1-GognAngular Parameters
Pre Post
Graph – II : Pre-Post Insignificant Angular Measurements
0
10
20
30
40
50
60
70
80
Deg
rees
Gogn-FH Gogn-PP Gogn-OP U.Gonial L.GonialAngular Parameters
Pre Post
Graph III : Pre-Post Insignificant Linear Measurements
0
20
40
60
80
100
120
140
160
mm
N-Me ANS-Me Se-Go OBLinear Parameters
Pre Post
Results
Graph IV : Pre-Post Anterior Tooth Movement
0
5
10
15
20
25
30m
m
BU1 TU1 BL1 TL1Linear Parameters
Pre Post
Graph V : Pre-Post Molar Movements
-20
-10
0
10
20
30
40
50
mm
SV-U6 Pog-L6 FH-U6 FH-L6Linear Parameter
Pre Post
Discussion
DISCUSSION
For evaluation of treatment results it is important to consider facial types.
Long faced individuals exhibit long anterior face height, excessive backward rotation
of the mandible, and high MPA.39,40 Similarly short anterior face height, excessive
forward rotation of the mandible and low mandibular plane angle has been reported
for short faced individuals.40,41
Schudy advocated extraction of teeth “to close the bite”, in hyperdivergent
facial type.4-6 Sassouni and Nanda concurred with a such a treatment phylosophys.7
Orthodontists generally agree that non-extraction treatment is associated with
downward and backward rotation of the mandible and an increase in the LAFH. They
also agree that extraction line of treatment is associated with upward and forward
rotation of the mandible and decrease in the LAFH.23
Previously published literatures9,10,23,27 showed that there is no significant
changes in the vertical facial dimension following first premolar extraction treatment.
The present study aimed to study the comparison of overbite and vertical facial
changes following first premolar extraction in high angle adult patients.
Twenty five adult patients having high mandibular plane angle i.e. GoGn-SN
greater than or equal to 32o were compared with pre and post treatment cephalometric
results. Pre and post treatment lateral cephalograms of all the adult 25 patients were
taken, obtained with patient positioned in the natural head position42,43 and evaluated
for pre and post treatment overbite and vertical facial dimensions. Frankfort
horizontal plane (porion to orbitale) was taken as a horizontal reference plane and a
perpendicular to this FH plane gives a judicial vertical plane, which was used to
evaluate the overbite changes.1
Discussion
To evaluate the mandibular plane angle, Gogn - SN plane was used, as given
by the Steiner’s analysis.44 N-Me and ANS-Me were used as landmarks and evaluate
the AFH and LAFH respectively. As Se point is stable, vertical line drawn
perpendicular to FH from sella was used to evaluate the mesial movement of
maxillary first molar and Pog vertical was drawn from Pog perpendicular to FH in
order to overcome the errors by mandibular rotation. Perpendicular line was drawn
from FH to mesiobuccal cusps of the maxillary and mandibular first molars to analyze
the extrusion of molars after treatment.38
The absolute measurements of vertical face height, the ratio of AFH / PFH,
MPA and incisor vertical heights did not show significant difference between the pre
and post treatment changes, following first premolar extraction in high angle cases.
This suggests that the treatment approach following first premolar extraction in high
angle cases does not affect the vertical proportions of the face.
Results in this study suggests that, there were no statistically significant
difference in the amount of change in the variables for TAFH and LAFH. This is
because of the extrusion of molars, which would compensate for the mesial migration
of the molars which would accounts for anchorage loss.
Kocadereli27 and Staggers9 showed that there was no statistically significant
difference in vertical dimension changes between first premolar extraction and non-
extraction groups, and orthodontic treatment produced increase in the cephalometric
vertical dimensions in both extraction and non-extraction groups. Chua et al23
examined the effects of extraction and non extraction on LAFH and reported a
significant increase in the non-extraction group and no significant change in the
Discussion
extraction group. Cusimano, McLaughlin et al10 found no difference in facial height
of hyperdivergent patients with first premolar extraction treatment.
Garlington and Logan studied vertical changes in high mandibular plane cases
following enucleation of second premolars and observed significant change in the
lower anterior face height due to forward rotation of the mandible, but there were no
significant changes in the total anterior face height. This suggests that there were
compensatory changes in the maxillary vertical growth.45 This study corroborates our
study, could be due to enucleation of second premolar might reduce the arch length
resulting skeletal changes, Whereas in this study there was no significant skeletal
changes, rather more of dental changes have occurred.
Baumrind45 reported that the mean increase in anterior lateral face height was
significantly greater in the Class II extraction subgroup than in Class II non extraction
group This does not agree with our results, probably due lack of class II mechanics as
the samples included in the study were Class I molar and canine relation. Kim et al33
tested the occlusal wedge hypothesis by comparing the mesial molar movement and
the changes in vertical dimension between first premolar and second premolar
extraction groups and concluded that there was no decrease in facial vertical
dimension regardless of maxillary and mandibular first premolar and second premolar
extraction.
The present study did not show the significant changes in AFH and PFH. This
is due to, though there is mesial movement of the molars and tend to reduce the bite,
extrusion of the molars tend to increase the downward and backward rotation of the
mandible and maintain the vertical reduction of the facial height. Our results goes in
favour of Hayasaki et al34 reported that the changes in the absolute magnitude of
anterior and posterior facial heights between extraction and non-extraction treatments
Discussion
in both Class I and Class II malocclusion patients. Their results conclude that facial
growth pattern in the vertical and anteroposterior position of the maxillary and
mandibular molars, in the absolute magnitude of anterior and posterior face heights, in
the ratios of lower posterior face height/lower anterior face height lower anterior face
height/total anterior face height are similar between extraction and non extraction
treatment, either in class I or class II malocclusions.
Al-Nimri35 compared the changes in facial vertical dimension in patients with
Class II division I malocclusion after extraction of either the mandibular first
premolar or second premolar. The forward movement of the mandibular molars was
greater in second pre molar extraction group and this is attributed to the larger
residual space in the lower arch after alignment in this group and difference in the
distribution of the anchorage values in the lower arch with in extraction group and
concluded that the mandibular premolar extraction, whether first or second was not
associated with mandibular over closure or reduction in facial vertical dimension,
despite more forward movement of the mandibular molars in second premolar
extraction group.
The analysis of the variables at pre-treatment and post-treatment in table III
suggests that there was some extrusion of maxillary and mandibular molars, which
were statistically significant. This could have been consequent to the
mechanotherapy9,10,46 or residual growth.33 Growth is nearly complete at 14 years in
girls and at 16 years in boys.38 The average age of the sample was 17.39 3.99 years.
So we can mention little about the influence of residual growth as it is limited at these
ages. The present study suggests that some residual growth as well as treatment
mechanics took place. This finding is similar to the studies of Kim et al 33 and Harris
et al47 with subject in the late teens.
Discussion
The maxillary and mandibular molars showed mesial movement in relation to
‘S’ vertical and Peg vertical respectively, which were statistically significant (Table
III). This movement may be consequent to mechanotherapy or residual growth. This
finding is similar to the studies of Gardner et al,48 West and McNamara49 in late teens
and Gesimano et al,10 Gardner et al48 reported that the horizontal distance of the
maxillary first molar measured in relation to pterygomaxillary vertical, continued to
increase mesial movement on an average of 2.6 mm from post treatment at the age of
16.6 years to the first recall examination at the age of 21.6 years.48 West and
McNamara reported the same with the molars in males and females with mean ages of
17 years 2 months and 17 years 6 months, respectively, erupted and moved mesially
during adulthood.49 In addition to this, the normal mesial displacement of the
maxillary and mandibular molars, mesial movement in the extraction group might be
allowed, depending on the severity of the anterior discrepancies.9,50
Mandibular plane angle showed statistically significant increase from pre-
treatment to post-treatment (Table 1). This is due to the extrusion of molars in both
maxilla and mandible. It could also be due to of residual growth as as explained
earlier. Another criteria for sample selection was high mandibular plane angle,
suggests that vertical jaw pattern. This finding supports the study done by Mc
Laughlin, Cusimano et al on effects of first premolar extraction on facial heights in
high angle cases. where as a study38 done by Arunachalam and Ashima Valiathan on
cephalometric assessment of dentofacial vertical changes in class I subjects
corroborates our findings. But the difference in the changes from pre-treatment (-0.5)
to post-treatment (1.0) is negligible. So we can say that though it is statistically
significant, it is clinically insignificant. This statistical change may be due to small
sample size.
Discussion
Overbite did not show any significant changes in this study. Probably due to
more of bodily movement of the incisors.
There was a statistically highly significant change in the U1-SN, L1-GoGn
(Table II) and BUI and BLI (Table 3) suggests that the most of the extraction space
was closed by upper and lower anterior retraction.
There was significant change in the tipping movement of upper and lower
anteriors (TUI and TLI) (Table III) suggesting that there was bite closure by tipping
movement of anteriors both in maxilla and mandible. There was no significant
changes in the pre and post treatment comparison of maxillary and mandibular
skeletal measurements (Table III) rather relative positions of the maxillary and
mandibular incisors were affected by treatment. These results goes in favor with the
study done by Mark G. Hans et al.1
There was a slight changes in the certain parameters shown in the Table I, II
and III. Although there was a slight change, the difference in the changes were very
less and statistically insignificant. This could be probably due to limitations of the
study which could be due to small sample size. Another limitation of the study is we
could not analyze in depth the response differences of different patients. For example,
in our study nine patients showed vertical reduction, but statistical evaluation masked
these findings. So it is better to assess an in-depth evaluation of vertical dimension
changes in each stage of treatment of the samples, and treatment results should be
contemplated with concomitant evaluation of the biomechanics of the
temporomandibular joint, since they do not function as simple hinges. So further
studies are required on the biological response to treatment effects as well as
compensatory mechanisms, particularly affecting vertical dimensions.
Conclusion
CONCLUSION
The intent of this investigation was to examine the popular “wedge
hypothesis” that the vertical dimension collapses following first bicuspid extraction
line of orthodontic treatment.
The results of this study leads to the following conclusion,
1. There was no linear change in the vertical facial dimension
2. There was no significant increase in the overbite
3. There was no clinically significant increase in the mandibular plane
angle
This study indicate that occlusal movement of the posterior teeth tend to keep
pace with the increase in anterior face height, thus maintaining the mandibular plane
angle and nullifying the bite closing effect of posterior protraction. The facial
complex does increase in size with growth, but Gogn – SN plane while moving
inferiorly, remain essentially parallel to its pretreatment position, due to residual
growth and treatment mechanics.
Summary
SUMMARY
The stimulus for this investigation was assertion that extraction treatment is
tantamount to reduction in facial vertical dimension and subsequent increase in depth
of the bite. In clinical practice most of the orthodontists believed the theory that
reducing tooth mass will lead to bite closure by accelerating the normal forward
growth rotation of the mandible. Such rotation, would, in theory, reduce the anterior
facial height and carry the chin forward. Most of the previous literature showed that
there was no significant change in the facial vertical dimensions following extraction
line of treatment.
The present study was designed to evaluate cephalometric overbite and
vertical height changes following first bicuspid extraction in high angle cases. i.e.
Gogn – SN ≥ 32 degrees.
A total of 25 adult patients having high mandibular plane angle (GoGn-SN ≥
32o) treated in the Department of Orthodontics, College of Dental Sciences,
Davangere, with all first bicuspid extraction over a period of 18 to 24 months, using
consistent biomechanical principles. In order to evaluate the overbite changes all pre
and post cephalograms were traced and measured in relation to the vertical fuducial
line drawn perpendicular to FH plane. Similarly various linear and angular
measurements were measured to evaluate the facial vertical dimensions.
Results showed that extraction line of treatment with all first bicuspids did
not show significant changes in overbite and vertical facial height after treatment.
There was a slight increase in the mandibular plane angle, but it was clinically
insignificant. However it should be interpreted with caution, given the small sample
size. The results in this study concludes that there is no vertical reduction in the facial
height following first bicuspid extraction, thus extraction of teeth solely to increase
the overbite or decrease the mandibular plane angle might not be justified.
Bibliography
BIBLIOGRAPHY
1. Hans MG, Groisser G, Oamon C, Amberman D, Nelson S, Palomo M.
Cephalometric changes in overbite and vertical facial height after removal of 4
first molar or first premolars. Am J Orthod Dentofacial Orthop 2006;130(2):
183-8.
2. Behrents RG, White RA. TMJ Research. Responsibility and risk. Am J Orthod
Dentofacial Orthop 1992;102(1):1-14.
3. Bernstein L. Edward H. Angle versus Calvin S. Case : Extraction v/s Non-
extraction. Part I Historical Revisionism. Am J Orthod Dentofacial Orthop
1992;102(5):464-70.
4. Schudy FF. Vertical growth versus anteroposterior growth as related function
and treatment. Angle Orthod 1964;34(2):75-93.Schudy FF. Angle Orthod
1964;34(2):75-93.
5. Schudy FF. The rotation of the mandible resulting from growth ; its implication
in orthodontic treatment. Angle Orthod 1965;35(1):36-50.
6. Schudy FF. The control of vertical overbite in clinical orthodontics. Angle
Orthod 1968;38(1):19-39.
7. Sassouni and Nanda. Dentofacial vertical proportions. Am J Orthod
1964;50(11):801-823.
8. Issacson JR, Issacson RJ, Speidel TM, Worms FW. Extreme variations in
vertical facial growth and associated variation in skeletal and dental relations.
Angle Orthod 1971;41(3):219-29.
9. Straggers JA. Vertical changes following first premolar extractions. Am J
Orthod Dentofacial Orthop 1994;105(1):19-24.
Bibliography
10. Cusimano C, McLaughlin RP, Zernik JH Effects of first bicuspid extractions on
facial height in high-angle cases. J Clin Orthod 1993;27(11):294-98.
11. Pearson LE. Vertical control through use of mandibular posterior intrusive
forces. Angle Orthod 1973;43(2):194-200.
12. Schoppe RJ. An analysis of second premolar extraction procedures. Angle
Orthod 1964;34(4):282-302.
13. Brensonis WL, Grewe JM. Treatment and post treatment changes in orthodontic
cases : Overbite and Overjet. Angle Orthod 1974;44(4):295-99.
14. Ketterhagen DH. First premolar or second premolar extractions : Formula or
Clinical Judgement. Angle Orthod 1979;49(3):190-98.
15. Gianelly AA, Hughes HM, Wohlgemuth P, Gielden G. Condylar position and
extraction treatment. Am J Orthod Dentofacial Orthop 1988;93(3):201-5.
16. Carter NE. First premolar extraction and fixed appliance in Class II division I
malocclusion. British Journal of Orthodontics 1988;15(2):1-10.
17. Hellekant M, Laugestrom L, Gleerup A. Overbite and overjet correction in
Class II Division 1 sample treated with Edgewise therapy. European Journal of
Orthodontics 1989;11():91-106.
18. Reyanders RM. Orthodontics and temporomandibular disorders – A review of
Literature (1966-1988). Am J Orthod Dentofacial Orthop 1990;97(6):463-71.
19. Gianelly AA, Cozzani M, Boffa T. Condylar position and maxillary first
premolar extraction. Am J Orthod Dentofacial Orthop 1991;99(5):473-6.
20. Luecke PE, Johnston LE. The effects of maxillary first premolar extraction and
incisor retraction on mandibular position. Testing the central elogma of
‘functional orthodontics’. Am J Orthod Dentofacial Orthop 1992;101(1):4-12.
Bibliography
21. Kremenak CR, Kirser DD, Harman HA, Menard CC, Jakobsen JR. Orthodontic
risk factors for temporomandibular disorders (TMD) : I premolar extraction.
Am J Orthod Dentofacial Orthop 1992;101 (1):13-20.
22. Klapper L, Navarro S, Bowman D, Pawloneski B. The influence of extraction
of non-extraction orthodontic treatment on bronchofacial and dolichofacial
growth patterns. Am J Orthod Dentofacial Orthop 1992;101 (5):425-30.
23. Chaw AL, Lim JYS, Lubit EC. The effects of extraction versus non-extraction
orthodontic treatment on growth of the lower anterior face height. Am J Orthod
Dentofacial Orthop 1993;104(4):361-8.
24. Luppanapornlarp S, Johnston LE. The effects of premolar extraction : A long-
term comparison of outcomes in ‘clear-cut’ extraction and non-extraction class
II patients. Angle Orthod 1993;63(4):257-70.
25. McLaunghlin RP, Bennett JC. The extraction – non-extraction dilemma as it
realist TMD. Angle Orthod 1995;65(3):175-86.
26. Savisay LT, Darendeliker N. The influence of extraction orthodontic treatment
on craniofacial structures. Evaluation according to two factors. Am J Orthod
Dentofacial Orthop1999;115(5):508-14.
27. Kocadereli I. The effects of first premolar extraction on vertical dimension.
Am J Orthod Dentofacial Orthop 1999;116(1):41-5.
28. Sanskey WL, Buschang PH, English I, Owen AH. Early treatment of vertical
skeletal dysplasia : The hyperdivergent phenotype. Am J Orthod Dentofacial
Orthop 2000;118(9):317-27.
29. Ahn JG, Schneider BJ. Cepahlometric appraisal of posttreatment vertical
changes in adult orthodontic patients. Am J Orthod Dentofacial Orthop
2000;118(4):378-84.
Bibliography
30. Lai J, Ghosh J, Nanda RS. Effects of orthodontic therapy on facial profile in
long and short vertical facial pattern. Am J Orthod Dentofacial Orthop
2000;118(5):505-13.
31. Avous A. Vertical changes following orthodontic extraction treatment in
skeletal openbite subjects. Eur J Orthod 2002;24(4):407-16.
32. Merel O, Iscan HN, Okay C, Giirsoy Y. Effects of bilateral upper first
premolar extraction on the mandible. Eur J Orthod 2004;24(3):223-231.
33. Kim TK, Kim JT, Mah J, Yang WS, Back SH. First or second premolar
extraction effects on facial vertical dimension. Angle Orthod 2005;75(2):177-
182.
34. Hayasaki SM, Henriques JFC, Janson G, Creitas MRd. Influence of extraction
and non-extraction orthodontic treatment in Japanese-Brazilians with Class I
and Class II Division 1 malocclusion. Am J Orthod Dentofacial Orthop
2005;127(1):30-6.
35. Al-Nimi KS. Vertical changes in class II division 1 malocclusion after
premolar extractions. Angle Orthod 76(1):52-58.
36. Kuitert R, Beckmann S, Loenen MV, Tainzing B, Zentner A. Dentoalveolar
compensation in subjects with vertical skeletal dysplasia. Am J Orthod
Dentofacial Orthop 2006;129(5):649-57.
37. Sharp C, Harkners M, Herbison P. Vertical changes in treated and untreated
class II division I malocclusion. Aust Ortho J 2007;23(2):114-120.
38. Sivakumar A, Valiathan A. Cephalometric assessment of dentofacial vertical
changes in Class I subjects treated with and without extraction. Am J Orthod
Dentofacial Orthop 2008;133(6):869-75.
Bibliography
39. Surendra K. Nanda. Growth patterns in subjects with long and short faces. Am
J Orthod Dentofacial Orthop 1990;98(5):247-58.
40. Opdebeeck H, Bell WH – The short face syndrome. Am J Orthod Dentofacial
Orthop 1978;73(5):499-511.
41. Moorrees CFA, Kean MR. Natural head position, a basic consideration in the
interpretation of cephalometric radiographs. Am J Phy Anthropol
1958;16(3):213-34.
42. Cooke MS Wei Stephen HY. The reproducibility of natural head posture : A
methodological study. Am J Orthod Dentofacial Orthop 1988;93(4):280-8.
43. Steiners CC. Cephalometric changes in clinical practice. Am J Orthod
1959;29(1):8-29.
44. Garlicuglenmound Logan LR. Vertical changes in high mandibular plane cases
following enucleation of second premolars. Angle Orthod 1990;60(3):263-267.
45. Baumrind S. Unbiased quantitative testing of conventional orthodontic beliefs.
Sem Orthod 1998;4:3-16.
46. Pearson LE. Vertical control through use of mandibular posterior intrusive
forces. Angle Orthod 1973;194-200.
47. Harris EH, Gardner RL, Vander JL. A longitudinal cephalometric study of
post-orthodontic craniofacial changes. Am J Orthod Dentofacial Orthop
1999;115(1):77-82.
48. Gardner RZ, Harris EH, Vanden JL. Postorthodontic dental changes. A long
study. Am J Orthod Dentofacial Orthop 1998;114(5):581-6.
Bibliography
49. West KS, McNamara JA. Changes in the craniofacial complex from
adolescence to midadulthood : A ceph Study. Am J Orthod Dentofacial Orthop
1999;115(5):521-32.
50. Stasgers JA. A comparison of results of II molar and I premolar extraction
treatment. Am J Orthod Dentofacial Orthop 1990;98(5):430-6.
Annexures
MASTER CHART - 1 : PRE – POST ANGULAR CEPHALOMETRIC MEASUREMENTS (IN DEGREES)
Sl.No. Name A
ge(Y
rs)
Sex
Gogn - SN Gogn - FH Gogn - PP Gogn-OP SN-PP SN - FH U1 - SN L1 - Gogn U.Gonial L.Gonial Y - Axis
PRE
POST
PRE
POST
PRE
POST
PRE
POST
PRE
POST
PRE
POST
PRE
POST
PRE
POST
PRE
POST
PRE
POST
PRE
POST
1 Veeranna 21 M 35 34 26 25 29 28 17 13 8 11 9 9 115 105 105 96 54 55 75 75 69 702 Manjunath M G 20 M 36 36 26 26 27 27 16 15 9 8 9 9 118 106 103 94 54 55 75 78 70 683 Santosh 19 M 34 34 27 27 26 26 16 16 9 9 8 8 114 106 101 93 52 52 72 73 67 684 Nabi 18.6 M 33 34 27 29 25 25 15 16 10 12 10 9 112 104 100 92 52 52 76 77 66 665 Lokesh 18 M 33 34 27 28 25 26 17 14 10 11 10 10 115 105 104 95 52 52 76 76 67 676 Pradeep 17.6 M 33 33 26 26 25 25 15 17 11 11 9 9 114 106 101 93 53 54 76 78 67 687 Basavalingappa 20 M 35 36 28 28 26 26 15 18 11 12 10 11 118 105 103 95 55 54 78 80 68 698 Pradeep 20 M 33 35 27 28 24 26 16 17 10 10 10 10 120 107 106 98 53 53 75 77 67 689 Sanketh 18 M 32 33 26 27 24 24 17 17 11 10 11 11 118 106 99 90 54 54 76 73 65 6510 Girish U T 21 M 34 33 27 27 24 25 16 17 11 10 10 10 120 108 104 97 55 55 79 75 67 6511 Praveen G M 18 M 32 33 26 27 24 24 17 17 10 9 10 10 117 107 98 90 54 54 76 75 66 6612 Basavaraj 20 F 35 36 26 26 26 26 15 14 8 7 10 9 119 107 103 95 54 54 78 78 69 6913 Tabussam 19 F 35 35 27 28 24 25 16 17 10 10 11 10 116 104 92 90 53 53 75 77 67 6814 Swathi 21 F 34 33 27 27 24 25 16 17 11 10 10 10 120 108 104 97 55 55 79 76 66 6715 Yasmeen 18.6 F 36 36 28 27 27 26 15 16 9 9 9 8 114 106 101 93 52 52 72 78 67 6816 Gowri 19 F 34 34 26 26 25 25 15 17 11 11 9 9 114 107 101 95 53 53 78 78 68 6817 Roopa 20 F 34 37 28 29 26 27 15 18 11 12 10 11 118 105 103 95 55 54 78 80 68 6918 Reena 21 F 34 33 36 25 29 28 17 13 8 11 9 11 115 105 105 96 54 54 75 75 69 7019 Sharada 20 F 32 33 26 27 24 24 17 17 11 11 11 10 118 106 99 90 54 54 76 73 65 6520 Ashwini 18 F 33 35 27 28 25 26 17 14 10 11 10 10 115 105 104 96 53 53 75 75 67 6721 Shobha 19 F 35 36 26 27 28 27 15 15 9 8 9 9 118 106 103 94 54 54 78 78 68 6822 Bhagya 19 F 33 33 26 26 25 26 15 18 11 12 10 11 118 105 103 95 53 53 77 77 67 6823 Vineeta 20 F 33 34 27 27 24 25 16 17 11 10 10 10 120 108 104 97 55 55 79 76 67 6524 Deepa 19.6 F 33 34 27 28 25 26 17 14 10 11 10 10 115 105 104 95 52 52 76 76 67 6725 Halamma 20 F 34 33 26 27 24 24 17 17 11 12 11 11 118 106 99 90 54 54 76 73 65 65
Annexures
MASTER CHART – 2 : PRE – POST LINEAR CEPHALOMETRIC MEASUREMENTS (IN MM)
Sl.No. Name Age
(Yrs) Sex
N – Me Se – Go N – ANS ANS-Me APF ht Rt SV - U6 Pog-L6 FH - U6 FH - L6
PRE
POST
PRE
POST
PRE
POST
PRE
POST
PRE
POST
PRE
POST
PRE
POST
PRE
POST
PRE
POST
1 Veeranna 21 M 129 128 78 78 55 55 74 73 60.4 60.9 40 42 -20 -18 47 49 48 472 Manjunath M G 20 M 128 130 78 79 55 55 75 73 60.7 60.1 41 43 -21 -19 46 48.5 47 45.53 Santosh 19 M 127 128 77 76 54 55 73 73 59.9 60.3 39 42 -19 -16 49 52 50 484 Nabi 18.6 M 125 127 76 75 54 53 73 74 60.8 59.1 40 43 -20.5 -17.5 47 48.5 48 475 Lokesh 18 M 124 124 74 73 51 51 73 75 59.6 59.4 40 42 -20 -18 48 50 49 476 Pradeep 17.6 M 124 124 72 72 53 53 71 71 58.6 58.1 39 42 -19 -16 48 50 50 487 Basavalingappa 20 M 127 125 75 73 54 54 73 71 59.1 59 39 41 -19 -17 46 48.5 47 458 Pradeep 20 M 128 127 76 77 52 52 76 75 59.3 60 39 42 -20 -17 48 49.5 49 47.59 Sanketh 18 M 124 123 73 72 51 51 74 73 58.8 58.5 40 42 -19 -18 45 48 46 4810 Girish U T 21 M 125 123 74 74 52 52 73 71 59.2 60.1 40 42 -20 -18 46 48 47 4911 Praveen G M 18 M 120 121 73 73 50 50 70 71 60.5 61 41 43 -21 -19 44 46.5 45 4712 Basavaraj 20 F 119 120 72 72 52 52 67 68 59.6 60.3 40 42 -20 -18 43 46 47 45.513 Tabussam 19 F 118 118 68 68 50 51 66 67 59.3 59.3 39 41 -19 -17 47 49 48 46.514 Swathi 21 F 129 128 71 72 52 53 67 68 60 60.1 41 43 -21 -19 46 48 47 45.515 Yasmeen 18.6 F 130 128 73 73 54 52 68 69 60.1 60.1 41 43 -21 -19 48 49.5 49 47.516 Gowri 19 F 127 128 70 70 51 51 67 67 59.4 59.9 40 42 -21 -19 49 51 50 4817 Roopa 20 F 128 125 72 72 52 52 67 68 58.6 58 40 42 -20 -18 47 49 48 46.518 Reena 21 F 127 124 71 71 52 52 66 66 59.3 59 41 43.5 -21 -18.5 44 46.5 45 4319 Sharada 20 F 124 124 69 69 53 53 65 65 60.1 60.3 42 45 -22 -19 45 47 46 4520 Ashwini 18 F 125 127 68 68 50 50 66 66 60 60.3 39 41 -19 -17 44 46.5 45 4421 Shobha 19 F 127 126 69 69 50 51 68 68 60.3 60.3 39 42 -19 16 44 47 45 4322 Bhagya 19 F 128 127 66 66 50 50 67 68 59.9 59.1 39 42 -18 -17 46 48.5 47 4523 Vineeta 20 F 124 126 67 67 52 53 66 65 59.1 59.4 40 42 -20 -18 48 50 49 4724 Deepa 19.6 F 124 126 74 73 51 51 73 75 59.6 59.4 40 42 -20 -18 47 49.5 48 4625 Halamma 20 F 124 123 73 72 51 51 74 73 58.8 58.5 41 43 -21 -19 47 49 48 46.5
Annexures
MASTER CHART – 3 : PRE – POST OVERBITE CEPHALOMETRIC MEASUREMENTS
Sl.No. Name Age
(Yrs) Sex MXSK BU1 TU1 BL1 TL1 MNSK OBPRE POST PRE POST PRE POST PRE POST PRE POST PRE POST PRE POST
1 Veeranna 21 M 17 19 15 17 19 20 28 23 13 12 72 74 147 1472 Manjunath M G 20 M 22 21 17 19 18 20 27 23 1 12 74 75 151 1523 Santosh 19 M 24 25.5 17 19 22 21 25 23 15 13 75 76 155 1544 Nabi 18.6 M 23 25 17 19 20.5 21 26 24 15 14 72 74 152 1515 Lokesh 18 M 24 25 15 18 19 21 26 23 15 14 76 74 153 1516 Pradeep 17.6 M 23 24 16 18 18 20 27.5 24 14 12 75 74 152 1507 Basavalingappa 20 M 25 26 16 20 20 22 26 23.5 13 12 74 75 151 1528 Pradeep 20 M 25 24 17 20 20 22 25 23 14 12 73 74 150 1529 Sanketh 18 M 25 24 18 21 20 22 26 24 14 12 74 72 152 152
10 Girish U T 21 M 25 23 16 19 19 21 27 24 15 13 74 73 153 15211 Praveen G M 18 M 24 23 17 20 19 21 25 24 13 12 73 72 147 14912 Basavaraj 20 F 24 25 15 19 19 21 25 22 12 11 73 74 146 14813 Tabussam 19 F 23 24 16 18 18 20 27 24 14 12 75 74 152 15014 Swathi 21 F 24 25 15 18 19 20 23 25 11 12 73 73 148 14915 Yasmeen 18.6 F 22 24 16 19 19.5 19 25.5 23 14 13 72 74 148.5 14816 Gowri 19 F 24 22 17 19 19 21 26 24 15 12 73 72 151 14917 Roopa 20 F 24 26 16 19 21 22 22.5 24 11 13 75 73 146.5 14918 Reena 21 F 25 24 17 20 20 21 24 22 13 11 74 72 149 14819 Sharada 20 F 23 24 16 18 21 22 24 22 15 14 75 76 152 15220 Ashwini 18 F 24 25 19 17 20 19 22 20 13 15 76 74 151 15021 Shobha 19 F 23 24 16 19 17 19 27 23 14 15 73 74 148.5 15022 Bhagya 19 F 22 23 17 19 19 18 29 26 14 11 17.3 76 149.5 14723 Vineeta 20 F 22 23 17.5 20 18.5 20 27 24 14 12 74 75 151 15224 Deepa 19.6 F 24 25 15.5 18 19 21 26 23 15 14 76 74 153.5 15125 Halamma 20 F 25 24 18 21 20 22 26 24 13 12 74 72 152 152