National trends in the prevalence and severity of the periodontal diseases.

In summary, between the 1960 to 1962 national health survey and the 1971 to 1974 national health survey, the mean periodontal index scores remained unchanged. However, the classification of adults into broad disease categories showed that those with no evidence of disease increased significantly. This improvement in the nation's experience with the periodontal diseases was restricted to those with gingivitis, and a concomitant improvement was observed in the nation's oral hygiene status; debris scores decreased substantially, whereas little change was observed in calculus scores. Hypotheses have been raised in this paper about the decline in the prevalence of gingivitis and its possible association with variables such as OHI-S scores, socioeconomic status, dental care utilization, cigarette smoking, fluorides, and antibiotics. Also noted between the two surveys was a slight decrease in the prevalence of periodontal pockets in persons younger than age 35, whereas in persons older than 35, there was either no change or a slight increase. During this same period, both total loss of teeth and number of missing teeth per person decreased for all ages. A hypothesis is proposed that links this slight increase in the more severe signs of periodontal disease in older adults to an increase in the number of teeth at risk to the disease. The modest change in the prevalence and severity of advanced periodontal disease may be an early sign of a trend that will become accentuated as a result of a distinct increase in the nation's older population coupled with the increased retention of the natural dentition. Thus, it would seem that a decline in edentulism and an increase in number of teeth per person may well contribute to circumstances that will lead to greater, not lesser, risk of advanced periodontal disease problems in the later decades of life. Although this hypothesis may or may not hold true for today's younger adults as they age, it seems to be the likely occurrence for the nation's older adults, at least for the next several decades. A third national survey, using the same indexes and more current periodontal disease measures, is needed to help to clarify the trends reported here.