RAJIV GANDHI UNIVERSITY OF HEALTH SCIENCES, KARNATAKA BANGALORE ANNEXURE II PROFORMA FOR REGISTRATION OF SUBJECTS FOR DISSERTATION 1. Name of the candidate and Dr. SHARMILA ARJUNAN address POST GRADUATE STUDENT (In block letters) DEPARTMENT OF ORTHODONTICS AND DENTOFACIAL ORTHOPEDICS, A.M.E’S DENTAL COLLEGE AND HOSPITAL, BIJENGERE ROAD, RAICHUR KARNATAKA-584103 A.M.E’S DENTAL COLLEGE AND 2. Name of the Institution HOSPITAL, BIJENGERE ROAD, RAICHUR KARNATAKA-584103 MASTER OF DENTAL SURGERY (MDS) IN 3. Course of the study and subject ORTHODONTICS AND DENTOFACIAL ORTHOPEDICS 26/5/2010 4. Date of admission to course 5. Title of the topic: “EVALUATION OF DENTOALVEOLAR AND SOFT TISSUE COMPENSATION IN VARIOUS SKELETAL MALOCCLUSIONS - A CEPHALOMETRIC STUDY” 6. Brief resume of the intended work: 6.1 Need for the study: During the process of facial growth and development, normal occlusion can be attained and maintained despite some variations in growth pattern, primarily as a result of dental compensation of skeletal malocclusions. Some physiological processes are needed during growth to co-ordinate the eruption and position of the teeth relative to their basal bones in order to maintain a normal relationship between the upper and lower dental arches despite some variations in growth pattern. As clinicians are now increasingly accepting the shift in paradigm, which states that both the diagnosis and orthodontic treatment planning are established more by soft tissue considerations than skeletal/ dental relationships, the need to include soft tissue compensation of skeletal malocclusions is considered significant. The differences in the interarch relationships of subjects with class I,II and III dental malocclusions are probably not directly due to differences in skeletal morphology, but rather to the fact that in the class I group, in contrast to class II and class III subjects, the variation in jaw relationship has been compensated for by the dentoalveolar compensatory mechanism. Therefore, a better understanding of the differences in dentoalveolar compensation in different skeletal malocclusions with varied overjet subjects may be useful in the analysis and treatment planning of orthodontic cases. 6.2 Review of literature: Ishikawa et al (1999)1 conducted a study to investigate dentoalveolar compensation for variations in sagittal jaw relationships in 44 adult females with normal incisor relationships and either skeletal class I or skeletal class III jaw relationships. Cephalometric analysis was performed to evaluate sagittal jaw relationship, maxillary and mandibular incisor inclination and the cant of occlusal plane. They concluded that the most appropriate cephalometric parameters describing dental compensation quantitatively were SN-AB as a skeletal measurement and SN-U1, SN-L1 and SN-OP as dental measurements. Ishikawa et al (2000)2 continued the previous study further to investigate dentoalveolar compensation in negative overjet cases wherein 88 adult females with either skeletal class I or skeletal class III jaw relations were examined. They statistically confirmed the compensatory changes for incisor inclination and occlusal plane angulation. However, the compensatory effects were weaker than in normal overjet cases, suggesting that negative overjet results from insufficient dentoalveolar compensation for variations in sagittal jaw relationships. Ceylan et al (2003)3 investigated the relationship between overjet and dentoalveolar compensation in different overjet patterns. The lateral cephalograms of 80 untreated subjects (40 males and 40 females) aged 13–15 years were divided into four groups based on a normal, edge-to-edge, negative, or positive overjet. Seven linear and eight angular cephalometric measurements were used to assess dentoalveolar compensation in the different overjet patterns, and the differences between the groups and between genders were assessed. The results showed that there were statistically significant differences in measurements of maxillary anterior and posterior alveolar and basal height (mm), and angles U1–NA, U1–L1, U1–SN, L1–– SN, L1––MP, and SN–AB among the overjet groups. Baydas et al (2004)4 compared the gender differences in the maxillary and mandibular morphology in different overjet groups. Lateral cephalometric radiographs of 80 untreated males and females (40 each) aged 13 to 15 years were traced. The subjects were divided into four overjet groups. The results showed statistically significant differences in maxillary anterior and posterior dentoalveolar heights, effective mandibular length, corpus length and ramus width between the overjet groups with measurements in males being significantly larger than in females. Kim et al (2005)5 conducted a study to classify normal occlusion samples into specific skeletal types and to analyze the dentoalveolar compensation in a normal occlusion in order to provide the clinically applicable differential diagnostic criteria for an individual malocclusion patient. Lateral cephalograms of 294 normal occlusion samples were measured. It was concluded that because the range of a normal occlusion includes quite diverse anteroposterior and vertical skeletal relationships, classifying the skeletal pattern and establishing an individual dentoalveolar treatment objective might facilitate clinical practice. 6.3 Objectives of the study: 1. To evaluate cephalometrically the various sagittal and vertical dentoalveolar compensations in different sagittal jaw relationships. 2. To evaluate soft tissue compensation in different sagittal jaw relationships. 3. To compare the dentoalveolar and soft tissue compensations in different sagittal skeletal relationships. 4. To compare the dentoalveolar compensations based on overjet value within different sagittal skeletal relations. 7. Materials and Methods 7.1 Source of data: A cross sectional cephalometric study will be conducted on 250 subjects. 7.2 Method of selection of data: INCLUSION CRITERIA: 1. Males and Females of 16 to 30 (average of 23) years of age. 2. A full complement of permanent dentition present (excluding third molar) EXCLUSION CRITERIA: 1. Previous history of orthodontic treatment or orthognathic surgery. 2. Previous history of trauma to maxillofacial structures. 3. Congenital deformities like Cleft lip and palate. 4. Compromised periodontal condition. SAMPLE SIZE AND DESIGN: Study will consist of 250 subjects aged between 16-30 years with different sagittal skeletal discrepancies and classified into control group (normal occlusion), group I, II and III based on sagittal skeletal relationship. Criteria for categorizing subjects: Control group – - Pleasing profile and symmetrical face. - Class I molar and class I canine relationship - Absence of rotations, spacing and crowding - Normal overjet and overbite. Group 1- Skeletal class I malocclusion - Beta angle6 between 270 – 350 - Wits appraisal between 0-1mm - Anteroposterior dysplasia indicator (APDI – facial plane angle +/- A-B plane angle +/- Frankfort palatal plane angle) – 77.60- 85.20 - APP-BPP7 (Distance between the projections of point A and point B on the palatal plane) between 2mm-8 mm. - The subjects of this group will be further divided based on their overjet into having 1. Overjet between 0-2mm 2. Overjet between 2-5 mm Group 2- Skeletal class II malocclusion - Beta angle less than 270 - Wits appraisal - more than 1mm - APDI – less than 77.60 - APP-BPP more than 8mm - The subjects of this group will be further divided based on overjet value as 1. Overjet of 5mm-8mm 2. Overjet of more than 8mm. Group 3- Skeletal class III malocclusion - Beta angle more than 350 - Wits appraisal - less than 0mm - APDI- more than 85.20 - APP-BPP less than 2mm. - The subjects of this group will be further divided based on overjet value as having 1. Overjet of 0 to -2mm 2. Overjet less than -2mm. METHODOLOGY: Standard Lateral Cephalometric radiographs will be taken in Natural head position (NHP). CEPHALOMETRIC ANALYSIS: All cephalometric radiographs will be exposed with standardized settings and the Frankfort horizontal plane parallel to floor. Reference planes used in the study 1. SN plane 2. Palatal plane ( ANS- PNS) 3. Functional occlusal plane (The midpoint of the overlap of the mesiobuccal cusps of the upper and lower first molars joined to a point bisecting the overbite of the incisors) 4. Mandibular plane (gonion to menton) 5. Facial plane (N-Pog) 6. N-A line 7. N-B line Dentoalveolar parameters are divided into Angular and Linear parameters. Angular parameters 1. U1-NA- Angle formed between maxillary central incisor and line joining nasion to point A. 2. U1-SN- Angle formed between the maxillary central incisor and line joining sella to nasion. 3. U1-L1- Angle formed between maxillary and mandibular central incisors. 4. S-N-Pr- Angle formed by joining sella, nasion and prosthion. 5. L1-NB- Angle formed between mandibular central incisor and line joining nasion to point B. 6. L1-SN- Angle formed between mandibular central incisor and line joining sella to nasion 7. L1-MP- Angle formed between Mandibular plane (gonion to menton) and mandibular central incisor. 8. S-N-Id- Angle formed by joining sella, nasion and infradentale. 9. SN-OP- Angle formed between sella nasion to occlusal plane. Linear parameters 1. U1-NA- Distance between maxillary central incisal edge to NA line 2. U1-NPog- Distance between maxillary central incisal edge to NPog 3. L1-NB- Distance between mandibular central incisal edge to NB 4. L1-NPog- Distance between mandibular central incisal edge to NPog 5. Mx AABH (Maxillary anterior alveolar and basal height) - The distance between the midpoint of the alveolar meatus of the maxillary central incisor and the intersection point between the palatal plane and the long axis of the maxillary central incisor. 6. Mx AD (Maxillary anterior depth)- The distance between points A and A’ (A’: From point A , a line is drawn parallel to the palatal plane intersecting the dorsal contour of the maxillary alveolar bone.) 7. MxPABH (Maxillary posterior alveolar and basal height)- The perpendicular distance between the midpoint of the alveolar meatus of the maxillary first molar and the palatal plane. 8. Md AABH (Mandibular anterior alveolar and basal height)- The perpendicular distance between the midpoint of the alveolar meatus of the mandibular central incisor and the mandibular plane. 9. Md PABH (Mandibular posterior alveolar and basal height)- The perpendicular distance between the midpoint of the alveolar meatus of the mandibular first molar and the mandibular plane. Soft tissue parameters include 1. Nasolabial angle (Cm- Sn- Ls)– Angle between Columella point, subnasale and Labrale superius 2. Facial convexity angle (G-Sn- Pg’) – Angle between glabella, subnasale and soft tissue pogonion. 3. Upper lip protrusion (Ls to (Sn-Pg’))- Distance between Labrale superius to line joining subnasale and soft tissue pogonion. 4. Lower lip protrusion (Li to (Sn-Pg’)) – Distance Labrale inferius to line joining subnasale and soft tissue pogonion. 5. Li- (Sn- Pg’) - Distance between Labrale inferius to line joining subnasale and soft tissue pogonion. 6. Ls- (Sn-Pg’) - Distance between Labrale superius to line joining subnasale and soft tissue pogonion. 7. Si- (Li- Pg’) – distance between mentolabial sulcus to line joining Labrale inferius and soft tissue pogonion. 8. Lower face –throat angle (Sn- Gn’- C) - Angle between Subnasale, soft tissue Gnathion and Cervical point. 9. Lower vertical height- depth ratio ( Sn-Gn’/C-Gn’) – Ratio between subnasale to soft tissue gnathion and cervical point to soft tissue gnathion. Statistical analysis The various dental and soft tissue measurements will be traced and mean values and standard deviations will be calculated within each group. Inter group comparisons will be done using appropriate statistical tests. 7.3 Does the study require any investigation or intervention to be conducted on patients or other humans or other animals? NO 7.4 Has ethical clearance been obtained from your institution in case of 7.3? YES 8. List of references: 1. Ishikawa H, Nakamura S, Iwasaki H, Kitazawa S, Tsukada H and Sato Y. Dentoalveolar compensation related to variations in sagittal jaw relationships. Angle Orthod. 1999, 69: 534- 538. 2. Ishikawa H, Nakamura S, Iwasaki H, Kitazawa S, Tsukada H and Chu S. Dentoalveolar compensation in negative overjet cases. Angle Orthod 2000; 70: 145-148. 3. Ismail Ceylan, Ibrahim Yavuz and Fatima Arslan. The effects of overjet on dentoalveolar compensation. Eur J Orthod 2003,25: 325-330. 4. Baydas B, Yavuz I, Dagsuyu IM, Bolukbasi B and Ceylan I. An investigation of maxillary and mandibular morphology in different overjet groups. Aus Orthod J 2004; 20, 11-18. 5. Kim Y, Lee SJ, Kim TW, Nahm DS and Chang . Classification of the skeletal variation in normal occlusion. Angle Orthod 2005;75:311–319. 6. Chong Yol Baik, Maria Ververidou. A new approach of assessing sagittal discrepancies: The Beta angle. Am J Orthod Dentofacial Orthop 2004, 126: 100- 105. 7. Nanda RS, Merrill RM. Cephalometric assessment of sagittal relationship between maxilla and mandible. : Am J Orthod Dentofac Orthop 1994; 105: 328-344.
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