Mandibular symphysis dimensions in different sagittal and vertical skeletal relationships.

BACKGROUND

The aim of this cross-sectional study was to compare the dimensions of mandibular symphysis (MS) between gender and the different sagittal and vertical skeletal relationships.

MATERIAL AND METHODS

Pre-treatment records of orthodontic patients were divided according to gender, sagittal (Class I, II and III) and vertical (decreased, average and increased mandibular plane [MP] angle) skeletal relationships. Measurements of MS parameters were performed on lateral cephalograms using IMAGEJ software. Comparisons between MS parameters and gender and the different skeletal relationships was performed using multifactorial and one-way ANOVA, and independent sample t-tests.

RESULTS

A total of 104 records (25 males and 79 females) fulfilled the inclusion criteria. Males had significantly greater MS surface area, dentoalveolar length, skeletal symphysis length, total symphysis length, vertical symphysis dimension and symphysis convexity ( < 0.05). Skeletal Class II patients had significantly greater dentoalveolar and skeletal symphysis lengths while Class III had greater chin length, vertical symphysis dimension and symphysis convexity ( < 0.05). Patients with decreased vertical dimension had greater skeletal symphysis length (p = 0.026) and those with an average vertical relationship had greater chin length (p < 0.001).

CONCLUSIONS

The morphology of the mandibular symphysis is affected by gender, sagittal and vertical skeletal patterns. Males had increased mandibular symphysis surface area and linear dimensions. Class II patients had greater dentoalveolar length. Chin length was greater in patients with an average MP angle.