[Discriminating factors of mandibular divergence]

The aim of this work is to identify the discriminating factors of mandibular divergence. 90 patient records taken from the 98--99. 99--2000 files in the orthopedic dentistry service of the Department of Odontology at Dakar University were examined. The patients selected were all of Black African descent and aged from 11 to 13. This work consists in the cephalometric examination of X-ray profiles radiographis in order to compare various elements between normodivergent and open-bite subjects. The statistical analysis of data along with various tests carried out led to the following conclusions: - Measuring FMA. GOI-Me/Oli, GOI-Me/Pocc, Ans-Pns/GOI-Me and chin angle can be used to discriminate between open-bite and normodivergent patients. - SN/GOI-Me has a positive correlation with GOI-Me/Oli, GOI-Me/ Pocc, Ans-Pns/Pocc, Ans-Pns/GOI-Me and FMA. - The chin angle has a negative correlation with the previous forms of measurements. - The correlation between Ans-Pns/Pocc and the other measures is weak. - The average difference between the measures of both groups is important, which means that these variables discriminate between normodivergent et open-bite patients. BIased on the most discriminating variables, we produced the following function of classification: F= - 1,542 -0,095(Angle) + 0.098(Ans-Pns/GOI-Me) + 0,145(FMA) We have also established an equation of probability for a patient to be normodivergent or open-bite, which is as follows: Pr (Normal) -----------=e(-0.273 FMA -0.267 ANS-NS/MEGOI +0.272 ANGLE) Pr (hyper)