Gingival-Bone Count: A Method for Epidemiological Study of Periodontal Disease

¹ Dental Health Service, Harvard University Health Services, Cambridge, Mass.

A new index is presented in which simple subjective measurements of gingival condition can be combined with simple proportional measurements of bone loss in order to produce a composite score, the original components of which can be identified. The term "GB count" is used to describe this composite score. It is felt that the method will prove more descriptive in epidemiological work than any of the existing methods that combine gingival and bone conditions indiscriminately.

A trial study of the method has been carried out on Harvard and Radcliffe students in whom gingival disease was not uncommon but bone loss was, for the most part, incipient. The GB count found was 1.79 out of a total possible score of 8. This figure was composed of scores of 1.12 for gingival disease out of a possible score of 3 and 0.67 for bone loss out of a possible score of 5.

Large standard deviations appeared in all measurements as a result of the high variability of periodontal disease. There was also a great difference between mean values obtained by clinical examination alone, those obtained by bite-wing X-ray alone, and those obtained by clinical plus bite-wing examination. However, when bone scores determined by bite-wing X-rays plus clinical examination were paired with bone scores by bite-wing alone, a high correlation coefficient (0.91) resulted.