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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