Pattern of bone loss in dry mandibles of individuals who died before 1957

To map out the pattern of periodontal disease in individuals who died before 1957 and were not exposed to formal dental services.

Descriptive cross-sectional study.

National Museums of Kenya.

The skeletons of people who died before independence are preserved at the National Museums of Kenya in Nairobi. Sixty four out of the 170 dry mandibles stored at the Museum were assessed for periodontal bone loss using a calibrated ruler.

All the 64 mandibles assessed were of individuals who died before 1957. Two thousand two hundred and seventy four sites were examined. Most of the subjects were adults aged 30-45 years and the age range was 18-80 years. Majority of the mandibles examined were of the ethnic group from Central Kenya. Of the teeth examined, premolars and molars were the teeth most frequently preserved intact in the sockets. The total mean bone loss for all teeth was 2.51 (SD 1.15) with a range of 0.85-5.80. When the different sites were examined, values for bone loss were 2.59 for mesial surfaces; 2.55 buccal surfaces; 2.38 for distal surfaces. Three categories were identified as follows:- 70% of the individuals had minimal or no bone loss, 26.5% had 3-4 mm or moderate bone loss and 3.5% had >5 mm bone loss or advanced bone loss. Further analysis showed that when bone loss of >3 mm was examined, only 28.12% of the individuals were in this group, 10.93% had >4 mm bone loss and 3.12% had 5 mm or more bone loss. The first molars were the teeth most commonly affected by bone loss of 3mm or more followed by second molars then the premolars.

In this group of individuals mainly from Central Kenya, the bone loss pattern showed that only a small number had experienced periodontal destruction as recorded by bone loss levels. Three groups were identified; those who had no or minimal destruction, those who had experienced moderate destruction and those where obvious bone destruction was evident. Thus susceptibility to periodontal disease is evident in a small proportion of individuals even in populations not exposed to modern diet and formal dental services. Periodontal destruction seems to affect a fraction of the population even when older populations are examined, thus it would save on resources both human and physical if these susceptible individuals could be identified early and treatment provided.