Cephalometric Profile of Bangladeshis: Tweed’s Analysis

Abstract

Introduction: Tweed’s diagnostic triangle is simple yet provides a definite guideline in treatment planning. The aim of the present study was to establish the Tweed’s norms for Bangladeshi people. Methods: The study was conducted for 89 Bangladeshi young adults (45 males and 44 females), aged 19–27 years, having balanced and harmonious facial profiles. Lateral cephalograms taken of these subjects were used for a series of morphometric analyses. Results: All three angular parameters Frankfort-mandibular plane angle (FMA), Frankfort-mandibular incisal angle (FMIA), incise mandibular plane angle (IMPA)were measured and found to be 24.52°, 54.60°, and 100.88°, respectively. The mean FMA has been found to be 24.52° (with a range of 14°–36°) which is quite close to Tweed’s norm and found to be statistically insignificant. However, IMPA and FMIA values of Bangladeshis found to be statistically significantly different from that of the Caucasians. The linear regression equation of IMPA on FMA was fitted, and the estimated value of IMPA was computed for a given FMA. Conclusion: The results support the idea that treatment objectives of IMPA should be considered according to the facial pattern, i.e., FMA. Ethnic variations of norms cannot be overlooked while outlining goals and planning the treatment.