[Morphological characteristics of inter-radicular space of the first and second lower permanent molars]

In this study, 537 extracted molars (261 first and 276 second molars) with well developed roots were examined to assess the width of the interradicular space and the shape of the furcation vault. The roots were set widely apart in 91.6% of the first and 64.8% of the second permanent molars, while the roots set closely together were observed in 8.4% and 27.9% of the first and second molars, respectively. Fuseg roots were found in second molars only, in 7.2% of cases. A flat furcation fornix was detected in 18.3% of the first and 14.0% of the second molars, whereas a convex shape was observed in 20.7% of the first and 10.5% of the second molars, respectively (P less than 0.001). A convex shape of furcation was found in 8.0% of the first and 27.3% of the second molars, respectively (P less than 0.001). Interradicular ridge was present in a very high percentage (52.9% of the first and 48.0% of the second molars). A concave shape of furcation fornix was statistically more frequent in molars with closely set roots for the first and second permanent molars (P less than 0.001). It seemed that the width of the interradicular space had no influence on the prevalence of interradicular bridges, regardless of type of molars involved.