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DISSERTATION - SYNOPSIS
DR.ANOOP.S
Post Graduate Student
Department Of Orthodontics
And Dentofacial Orthopedics
A.J.INSTITUTE OF DENTAL SCIENCES, KUNTIKANA,
MANGALORE.
2011-2012
Rajiv Gandhi University of Health Sciences, Karnataka,
Bangalore
ANNEXURE II
PROFORMA FOR REGISTRATION OF SUBJECTS FOR DISSERTATION
1.
Name of the Candidates
And Address
(in block letters)
DR ANOOP. S
POST GRADUATE STUDENT,
DEPARTMENT OF ORTHODONTICS
AND DENTOFACIAL ORTHOPEDICS,
A.J.INSTITUTE OF DENTAL SCIENCES.
KUNTIKANA,
MANGALORE.
2.
Name of the institution
A.J.INSTITUTE OF DENTAL SCIENCES
3.
Course of study and subject
MASTER OF DENTAL SURGERY
ORTHODONTICS AND DENTOFACIAL
ORTHOPEDICS
4.
Date of admission to course
18.04.2011
5.
Title of the topic:
“RELATIONSHIP BETWEEN MAXILLARY
AND MANDIBULAR BASE LENGTH AND
DENTAL CROWDING IN PATIENTS WITH
CLASS III MALOCCLUSION ’’
6.
Brief resume of the intended work:
6.1 Need for the study

The relationship between apical base lengths and anterior dental
crowding in a sample with Class III malocclusions exclusively has not
been investigated.Therefore, the objective of this study is to evaluate
the relationship of maxillary and mandibular effective lengths
to the amount of anterior dental crowding in patients with
Angles Class III malocclusion. Anterior crowding is one of the most
common problems that motivate patients to seek orthodontic treatment.
Many factors have been evaluated and found to be related to anterior
dental crowding, including dental arch width and length ,mesiodistal
tooth diameter, and dental proportion. Crowding is often related to arch
dimensions. Only few studies evaluated the relationship between
crowding and cephalometric measurements.
Patients with Class III malocclusion have more mandibular length than
subjects with Class I malocclusion.
6.2 Review of literature:
1. Guilherme Jansona, Oscar Edwin Francisco Murillo Goizuetab;
Daniela G. Garibc; Marcos Jansond (2011)1 conducted a study to verify
the relationship between maxillary and mandibular effective lengths and
dental crowding in patients with Class II malocclusions. The sample
comprised of 80 orthodontic patients with complete Class II
malocclusions in the permanent dentition (47 male, 33 female) who were
divided into two groups according to the amount of mandibular
tooth-arch size discrepancy. The maxillary and mandibular effective
lengths (Condylon-point A and Condylon-Gnathion) and tooth-arch size
discrepancies were measured on the initial cephalograms and
dental casts.They concluded that Patients with Class II malocclusion and
moderate to severe crowding had significantly smaller maxillary and
mandibular effective lengths than subjects with the same malocclusion
and slight mandibular crowding.
2. Eduardo Bernabe, Carlos Flores-Mirb ( 2006)2 conducted a study
to compare, combined and individually, the mesiodistal (MD) and
buccolingual (BL) tooth sizes as well as their respective
crown proportions in the permanent dentition in dental arches with
moderate, mild, and no crowding. Dental casts from two-hundred
school children from a typical high school from Lima, Peru, in the age
group of 12-16 years were used. The mesiodistal and Buccolingual tooth
sizes of all permanent teeth except second and third molars were
measured, and their crown proportion (MD/BL ratio) was estimated.
Each dental arch was classified as presenting moderate (25.1 mm or more
of discrepancy), mild (20.1 and 25 mm of discrepancy), and no crowding
(zero or a positive discrepancy).They concluded that Dental arches with
moderate, mild, and no crowding differ most of the times significantly in
their mesiodistal tooth sizes and crown proportions individually or
combined but not in their buccolingual tooth sizes.
3. Noriko Shigenobua; Masataka Hisanob; Sachiko Shimac;
Nozomu Matsubarad; Kunimichi Somae (2006)3 conducted a study
to investigate the patterns of dental crowding in the lower arch and their
contributing morphological and functional factors. Pretreatment
diagnostic materials from 168 patients exhibiting dental crowding were
selected, and the patients, dental casts, lateral cephalograms, and occlusal
forces were evaluated.They concluded that the prevalence of dental
crowding was highest in the anterior region and was related to the same
tooth on each side (eg, right lateral incisor vs left lateral incisor). In the
premolar and molar region, the prevalence of dental crowding was related
to the adjacent tooth (eg, right first premolar vs second premolar). Three
crowding patterns were found in the anterior region: (1) a ‘‘symmetry
pattern,’’ (2) a ‘‘rotation pattern,’’ and (3) an ‘‘irregular pattern.
4. Hakan Turkkahramana; M. O zgu r Sayina ( 2004)4 conducted a study to
find dentofacial factors that might be associated with mandibular
crowding in the early mixed dentition. Lateral cephalograms and dental
casts of 60 children (33 girls, 27 boys) were evaluated. It was determined
that patients with crowding had smaller lower incisor to NB angles,
maxillary skeletal lengths, mandibular skeletal length, and mandibular
dental measurements. They also had greater interincisal angles, overjet,
overbite, and Wits appraisal measurements. Significant inverse
correlations were found between crowding and SNB, lower incisor to NB
angle, anterior cranial length, mandibular length, maxillary length,
mandibular dental measurement and direct correlations between
crowding and interincisal angle, overjet, overbite, and FMIA. According
to these results, they concluded that crowding of the mandibular incisors
is not only a tooth-arch size discrepancy. Dentofacial characteristics also
contribute to this malalignment.
5. Miho vil Strujic Sandra Anic-Milosevic, Senka Mestrovic and
Mladen sla (2009)5conducted a study to determine whether there is a
difference in the incidence of tooth size discrepancies among different
skeletal malocclusion groups and if gender dimorphism exists. The dental
casts and lateral cephalometric radiographs of 301 Croatian subjects (127
males and 174 females, mean age 16.86 ± 2.93 years) were selected.
They concluded that tooth size discrepancy was found to be more
frequent in the anterior region with respect to gender. A tendency was
found for mandibular tooth size excess in Angle Class III malocclusion
subjects and maxillary tooth size excess in those with an Angle Class II
malocclusion.
6.3 Objectives of the study:
The purpose of this study is to verify the relationship between maxillary and
mandibular effective lengths and dental crowding in patients with Class III
malocclusions
The evaluation will be done for :
Obtaining relation between apical base effective lengths and dental crowding in
class III patient.
7
Material and methods:
7.1 Source of data:
Lateral cephalogram and dental cast of 60 patients will be collected.
7.2 Methods of collection of data(including sampling procedure,if any)
The data is collected from 60 patients(30 males and 30 females) of age 12 to 20
years.
Inclusion criteria
Chronological age from 12 to 20 years
Presence of Angles class III malocclusion .
Presence of all permanent teeth upto first molars
Absence of dental anomalies of number ,size,form and position
Absence of proximal carious lesion
METHODOLOGY
Lateral cephalometric radiograph and dental cast of 60 Indian young patients(30
males and 30 females) of age group ranging from 12 to 20 years is obtained.
Lateral cephalogram will be taken on KODAK 8000C digital panoramic and
cephalometric system with exposure values set at 72KVP. 11mA and a
maximum exposure time of 1.2 seconds. All the subjects will be positioned in the
cephalostat with sagittal plane at right angle to the path of X-ray, the Frankfort
plane parallel to the horizontal ,the teeth in centric occlusion and the lips relaxed.
The radiographs will be traced and measured by the same investigator.
All radiographic assessments will be performed in a darkened room.Any
radiograph that showing poor contrast is discarded.
Impressions of the maxillary and mandibular arches will be recorded using
alginate impression material and the stone casts will be poured immediately.
- Instrument used for the measurement of widest mesiodistal dimensions will be
the DIGITAL VERNIER CALIPER. The mesiodistal width of the teeth anterior
to the first molars is measured using digital vernier caliper.
The arch length anterior to the first permanent molar will be measured using a
soft brass wire. Mandibular and maxillary crowding will be calculated as the
difference between arch perimeter and the sum of tooth widths from the second
premolar to the second premolar on the other side, in millimeters, and calculated
by a single examiner.
The sample will be divided into two groups according to severity of
anterior
crowding. First group includes crowding less than 2.5 mm & second group
includes crowding more than 2.5 mm.
The maxillary and mandibular effective lengths (Co-A and Co-Gn) will be
measured.
Correlation between base length and dental crowding is examined by means of
Pearson’s correlation coefficient which is calculated using following method.
Mandibular crowding x Co-A
Mandibular crowding x Co-Gn
Maxillary crowding
x Co-A
Maxillary crowding
x Co-Gn
Maxillary crowding
x mandibular crowding .
Co-A
x Co-Gn
7.3 Does the study require any investigations or interventions to be
conducted on patients or other humans or animals? If so, please.
describe briefly.
Lateral cephalogram and dental cast obtained from human samples.
7.4 Has ethical clearance been obtained from your institution in case
of 7.3?
Yes
INVESTIGATION DESIGN
Lateral cephalometric radiograph and dental cast of 60 Indian young patients(30
males and 30 females) of age group ranging from 12 to 20 years having Angles
classIII malocclusion will be taken
The sample will be divided into two groups according to severity of anterior crowding.
First group – crowding less than 2.5
mm
second group- crowding more
than 2.5 mm.
The maxillary and mandibular effective lengths (Co-A and Co-Gn) will be measured
Correlation between base length and dental crowding will be examined by
means of Pearson’s correlation coefficient
8.
List of references:
1. Guilherme Jansona, Oscar Edwin Francisco Murillo Goizuetab, Daniela G.
Relationship between maxillary and mandibular base length and dental crowding
in patient with complete classII malocclusion.Angle Orthod 2011:81:217-221
2. Eduardo Bernabe, Carlos Flores-Mirb. Dental morphology and crowding .
Angle Orthod 2006:76:20–25.
3. Noriko Shigenobua, Masataka Hisanob, Sachiko Shimac. Patterns of Dental
Crowding in the Lower Arch and Contributing Factors. Angle Orthod 2007: 77:
303-310.
4. Hakan Turkkahramana, M. O zgur Sayina. Relationship Between Mandibular
Anterior Crowding and Lateral Dentofacial Morphology in the Early Mixed
Dentition . Angle Orthod 200:74:759–764
5. Miho vil Strujic Sandra Anic-Milosevic, Senka Mestrovic andMladen sla
Tooth size discrepancy in orthodontic patients among different malocclusion
groups.European journal of orthodontics 2009:31:584-589.
6.Bernabe E,Flores-Mir C.Dental morphology and crowding .a multivariate
approach.Angle Orthod 2006:76:20-25
7.Doris JM ,Bernard BW,Kuftinec MM,Stomd. A biometric study of tooth size
and dental crowding .Am J Orthod . 1981:79:326-336
8. Puri N, Pradhan KL, Biometric study of tooth size in normal, crowded, and
spaced permanent dentitions. Am J Orthod . 2007:132:279e7-279e14.
9. Mills LF. Arch width, arch length and tooth size in young males. Angle
Orthod. 1964:34:124–129.
9.
Signature of candidate
10.
Remarks of the guide:
11.
Name & Designation of
(in block letters):
11.1 Guide:
DR. ROHAN RAI,
PROFESSOR AND HOD,
DEPARTMENT OF ORTHODONTICS
AND DENTOFACIAL ORTHOPEDICS,
A.J.INSTITUTE OF DENTAL SCIENCES
11.2 Signature:
11.3 Co-Guide (if any)
DR. K. NILLAN SHETTY,
PROFESSOR,
DEPARTMENT OF ORTHODONTICS
AND DENTOFACIAL ORTHOPEDICS,
A.J.INSTITUTE OF DENTAL SCIENCES
11.4 Signature:
11.5 Head of Department
DR. ROHAN RAI,
PROFESSOR AND HOD,
DEPARTMENT OF ORTHODONTICS
AND DENTOFACIAL ORTHOPEDICS,
A.J.INSTITUTE OF DENTAL SCIENCES
11.6 Signature
12.
12.1 Remarks of the Chairman &
Principal: DR. B SURESHCHANDRA
12.2 Signature