Comparative Study of Mandibular Morphology in Patients with Hypodivergent, Hyperdivergent and Average Growth Patterns: A Cephalometric Study

Santhosh Reddy, B (2011) Comparative Study of Mandibular Morphology in Patients with Hypodivergent, Hyperdivergent and Average Growth Patterns: A Cephalometric Study. Masters thesis, J.K.K. Nataraja Dental College, Komarapalayam.


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INTRODUCTION: Craniofacial Biology is the study of the “development, growth and adaptation, both phylogenetically and ontogenetically, of the craniofacial skeleton and related structures” The condylar cartilage acts as a regional adaptive growth site during mandibular growth. Absence of the condyles affects the amount of mandibular growth. Deviations in condylar growth can affect facial esthetics. Mechanical compression induces chondrogenesis and condylar growth. Masseteric resection in growing rats caused bradyauxesis of the mandibular condyles, indicating that occlusal force may also affect condylar growth. Occlusal force, maxillofacial morphology and mandibular condyle morphology seem to influence each other, but the relationship between occlusal force and mandibular condyle morphology has not been reported. AIMS AND OBJECTIVES: The present study was undertaken with the following aims and objectives: 1. To evaluate the mandibular morphology in average growth pattern, hypo divergent growth pattern, and hyper divergent growth pattern. 2. To compare the mandibular morphology between a) Average and hypodivergent pattern, b) Average and hyper divergent pattern, c) Hyper divergent and hypo divergent patterns. METHODOLOGY: For the present study, a sample of 60 randomly selected adult female patients with an age above 18 years were selected from department of Orthodontics, J.K.K. Nataraja Dental College & Hospital, Komarapalayam, Namakkal Dist. Ethical clearance was obtained from the institution. Criteria for selection of patients; 1. No severe craniofacial disorders, 2. No history of previous orthodontic treatment, 3. No missing maxillary and mandibular first molar and anterior teeth, 4. 60 patients in the age group range 18 years and above were selected. Source of data: The study was performed on the basis of standard lateral cephalograms of the patients and the cephalograms were traced. Cephalometric measurements were carried out manually using Bjork signs. METHOD: Materials for radiographs: Lateral cephalograms to evaluate the dentoskeletal features. For exposing lateral cephalometric radiograph, 8x10” Kodak film, 8x10” cassette with Kodak intensifying screens, Digital cephalostat. Cephalometric Technique: Standardization and accuracy in relationship of the tube head to cephalostat were most important. Standard lateral cephalograms were taken with the target film distance 17.14cm, 73 KVp, 15ma and 9.4 seconds exposure time. STATISTICAL ANALYSIS: NULL HYPOTHESIS: There was no significant difference in the mean values of the three groups i.e. μ1 = μ2 = μ3. ALTERNATE HYPOTHESIS: There was a significant difference in the mean values of the three groups i.e. μ1 ≠ μ2 ≠ μ3. LEVEL OF SIGNIFICANCE: α=0.05. STATISTICAL TECHNIQUE USED: Analysis of Variance (ANOVA). DECISION CRITERION: The decision criterion was to reject the null hypothesis if the p-value was less than 0.05 otherwise we accepted the null hypothesis. If there was a significant difference between the groups, we carried out multiple comparisons (post-hoc test) using Bonferroni test. COMPUTATIONS: The following tables gave us the results from ANOVA and the P-Value. CONCLUSION: As according to our study, using Bjork signs for mandibular morphology: 1. Condylar head was inclined more backwardly and more forwardly in hyperdivergent, average and hypodivergent patterns respectively. 2. Inferior border of mandible had a notched appearance in hyperdivergent, average growth and almost flat in hypodivergent patterns. 3. Anterior lower facial height increased in hyperdivergent fallowed by average growth pattern and decreased in hypodivergent patterns. 4. Interincisal, intermolar and inter premolar angles were more mesially inclined in hyperdivergent, average growth pattern than hypodivergent patterns. 5. Symphysis was more forwardly inclined in case of hypodivergent and backwardly inclined in hyperdivergent and average growth patterns. 6. Hypodivergence growth pattern is more easily identified than hyperdivergent and average growth pattern.

Item Type: Thesis (Masters)
Uncontrolled Keywords: Comparative Study ; Mandibular Morphology ; Patients with Hypodivergent ; Hyperdivergent ; Average Growth Patterns ; Cephalometric Study.
Subjects: DENTAL > Orthodontics and Dentofacial Orthopedics
Depositing User: Kambaraman B
Date Deposited: 12 May 2018 08:00
Last Modified: 12 May 2018 08:00

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