Variation of posterior approximal caries incidence with consumption of sweets with regard to other caries-related factors in 15-18-year-olds.

The aim of this study was to analyze the relationships between caries incidence and a number of caries-related factors in 15-18-yr-olds, in order to estimate the explanatory value of consumption of sweets under different conditions. Sixty-nine 18-yr-olds were interviewed about consumption of sweets and other sugar-containing products during the past 3 yr. Data on oral hygiene, salivary counts of mutans streptococci and lactobacilli, salivary flow rate and oral sugar clearance time were collected when the individuals were 15 and 18 yr old. Caries incidence for the 3-yr period was expressed as a percentage of the number of caries-free approximal surfaces of premolars and molars at the age of 15. Simple linear correlations between caries incidence and the different variables showed that lactobacilli count ranked first (r = 0.26), sweets second (r = 0.25), and mutans streptococci count third (r = 0.24). The r value for caries incidence and consumption of sweets increased in subgroups with combinations of poor oral hygiene, a high intake of other sugary products and a low salivary flow rate (r = 0.67-0.70). In conclusion, consumption of sweets should still be considered an important caries-related factor and particularly harmful when oral hygiene is poor and consumption of other sugary products is high.