5-YEAR INCIDENCE OF CARIES, SALIVARY AND MICROBIAL CONDITIONS IN 60, 70 AND 80-YEAR-OLD SWEDISH INDIVIDUALS

The 5-year incidence of dental caries in a random sample of 60-, 70- a nd 80-year-old inhabitants of Goteborg was related to salivary and mic robial conditions. Of the 208 persons examined at baseline, 148 (71%) participated in the follow-up examination; 69, 51 and 28, respectively , in the different age groups. The study revealed that 27% of the part icipants had not developed any carious lesions during the 5-year perio d and that the incidence of coronal and root caries increased with age . In the 60-year-olds, 2.5% of the susceptible coronal and root surfac es, respectively, had decayed? while the corresponding figures for the 80-year-olds were 8.8% for coronal surfaces and 9.8% for root surface s. In all, 18% had an unstimulated saliva secretion rate of below 0.1 ml/min and 14% had a stimulated secretion rate of <0.7 ml/min, with a mean rate which decreased with increasing age from 2.0 to 1.6 and 1.3 ml/min (p = 0.02). The overall salivary counts of lactobacilli and mut ans streptococci, particularly the subspecies of Streptococcus sobrinu s, had increased during the period. In the respective age groups of 60 , 70 and 80 years, 15, 39 and 39% had a mutans streptococci count of g reater than or equal to 10(6) CFU/ml in saliva and the corresponding f igures for greater than or equal to 10(5) lactobacilli counts were 22, 31 and 43%. In the stepwise regression analysis, it was found that ag e, salivary levels of mutans streptococci and lactobacilli and number of teeth were the best predictors of the incidence of root caries. In conclusion, these observations indicate that there is an increased ris k of dental caries with age owing to unfavourable microbial and saliva ry conditions.