Mandibular First Molar Furcation Lesions in Adult African Skulls

Objectives: The study was to measure furcation lesions [FL] on the buccal and lingual of first molars (M1) in dried human mandibles. Methods: All mandibles in the Raymond Dart Collection at the University of the Witwatersrand from Black Africans, with no carious or restored teeth, second premolar and second molar present, in decades 30-39y (n=29), 40-49y (n=30), 50-59y (n=31) and >=60y (n=16) were the study sample. Each mandible was examined visually [V] and standardised photographs [P] (occlusal, right and left buccal and lingual views) were made. The V and P prevalence and severity of FL (Class I, II or III) was determined as well as the position of M1 in the arch using a French curve, within [W] buccal [B], or lingual [L] were recorded. Results: FL rates showed a statistically significant increase with age from 49% at 30-39y to 86% at >=60y with V and P (Chi square for trend p<0.01) with an overall rate of 75%. Rates were similar on both sides but buccal rates were significantly higher than lingual with both V and P (Fishers test p<0.01). M1 position in arch rates were W 45% B 36% L 19%. The lowest FL rates were on the lingual when M1 was on the L of the arch. Conclusions: The increase in rate of FL with age is logical and expected. Overall FL prevalence of 75% is higher than the 49% in an earlier study on mainly younger mandibles (Volchansky et al. 1978). The lower FL rate on the lingual of M1 is a new finding. We speculate that the lingual position of M1 may be protective. Visual examination of a mandible has advantages but this study indicates that stored standardised photos may also be used for measurements.