ABSTRACT
Objective: This study determined the relationship between masseter muscle thickness and overbite values among Nigerians. Methods: The subjects included 66 consecutive patients (21 males and 45 females) who presented for fixed orthodontic appliance treatment. Overbite values were measured from standard lateral cephalometric radiographs taken for all patients,who were thereafter divided into three groups of reduced overbite (n=22, mean -1.11+ 2.18mm), normal overbite (n=22, mean 2.59+0.50mm) and increased overbite (n=22, mean 5.21+1.39mm). The masseter muscle thickness of each patient was measured bilaterally using ultrasonography. Associations between masseter muscle thickness and different overbite values were analyzed using unpaired t-test, ANOVA and Tukey's multiple comparison analysis. Results: Mean masseter muscle thickness was 11.23 ± 2.40 mm during relaxation and 12.81 ± 2.64 mm during contraction for study participants. The masseter muscle on the habitual side of mastication of participants was generally thicker but the difference was not statistically significant (P>0.05). There was a progressive increase in masseter muscle thickness from reduced overbite through normal overbite to increased overbite groups and the differences were statistically significant (P<0.01). Tukey's multiple comparisons showed significant differences between all the three overbite groups (P<0.05). Conclusion: There was a direct relationship between the muscle thickness and overbite variations (AU)
Subject(s)
Humans , Male , Female , Adolescent , Adult , Masseter Muscle , Mastication , OverbiteABSTRACT
Background: The thickness of the masseter muscle during relaxation and contraction states was measured by ultrasonography. Subjects were classified according to their sagittal skeletal relationships. The association between muscle thickness and facial morphology was studied. Context: Masseter muscle thickness influences the skeletal patterns. Aim: To measure and compare the thickness of the masseter muscle in individuals with skeletal class I occlusion and skeletal class II malocclusions and to correlate its relationship with craniofacial morphology. Settings and Design: The study was conducted in a hospital setup and was designed to study the thickness of the masseter muscle in different skeletal morphologies. Materials and Methods: Seventy two individuals between the ages of 18 and 25 years were divided into Group I, Group IIA and Group IIB according to their skeletal relationships. Masseter muscle thickness was measured by ultrasonography. Eight linear and six angular cephalometric measurements were assessed. Statistical Analysis Used: Analysis of variance and Pearson's correlation analysis. Results: There was a statistically significant difference in muscle thickness between subjects of different skeletal patterns. Significant positive correlation between masseter muscle thickness and posterior total face height, jarabak ratio, ramus height, mandibular length and significant negative correlations with mandibular plane angle, gonial angle and PP-MP angle were observed. Conclusion: This study indicates the strong association between the masseter muscle and skeletal morphology.