Radix paramolaris and radix distomolaris in Danish permanent maxillary molars.

The School of Dentistry in Copenhagen possesses a collection of 96 human permanent maxillary molars (M sup) with a root complex, the macromorphology of which includes a facially located supernumerary root known as radix paramolaris (RP) and/or a distally located supernumerary root called radix distomolaris (RD). Systematic analysis of these teeth enabled the authors to establish precise criteria for the identification of RP and RD on M sup; 91.5% out of a total of 70 RP identified occurred on M3 sup, 7.2% on M2 sup, and 1.4% on M1 sup. The corresponding percentages for 29 RD identified were: 96.5% on M3 sup, 3.4% on M2 sup, and 0.0% on M1 sup; 50.0% of the 70 RP were separate in relation to the 2 facial root components and 31.5% non-separate; in 18.6% of the RP observed, it was impossible to establish whether or not they were separate. Corresponding frequencies for the 29 RD in relation to the distofacial and lingual root components were 41.3% separate and 37.9% non-separate; 20.7% of the roots could not be categorized. The following clinically relevant macromorphological variables regarding RP and RD were also observed: degree of separation in relation to the respective neighboring root components, degree of divergence in relation to the same macrostructures, apical bend, apical gracility, and pattern of fusion.