[Analysis of factors influencing the amount and localisation of residual ridge reduction of mandible].

The objective of this study was to determine, on a certain number of edentulous patients, the correlation between some parameters of residual ridge reduction (RRR)--(age of patients; parodontopathy as cause of teeth extraction; period of edentulousness; period of denture wearing and reasons of renewed dentures) and classes and sub-classes of RRG in the frontal and molar regions. The aim of these comparisons was to precisely determine the possible presence of loccus minoris of reduction in relation to the studied zones and the mentioned factors of the loss of residual ridge (RR). The study concerned 35 lateral head films of edentulous patients chosen at random. By intersection of data and by their statistical processing, it was established that all reduction parameters, except the age of patients, were important factors or co-factors of this process. They had no specific effect RR. The finding that the molar region was more jeopardized by reduction was explained by the fact that the period of edentulousness and denture wearing were in function of the time, due to an unequal rate of teeth extraction, and that they became the true reason of a more severe reduction and the molar region a more susceptible area to this process.