The relationship of dental calculus to caries, gingivitis, and selected salivary factors in 11- to 13-year-old children in Chiang Mai, Thailand.

Thai children have been shown to accumulate large amounts of dental calculus. The purpose of this study was to examine the relationship of calculus to caries and gingivitis, and salivary conditions which may contribute to calculus accumulation. Four-hundred and thirty-nine (439) children from 18 schools in Chiang Mai were selected for this study. The children were given oral examinations to determine calculus index (CI); decayed, missing, and filled surfaces (DMFS); decayed, missing, and filled teeth (DMFT); gingival index (GI); and plaque index (PI). Children with mean CI scores > or =1 (206) were assigned to the calculus group; the 233 children with mean CI scores of <1 to the noncalculus group. Saliva was collected from 60 randomly-selected children in each group. Unstimulated and stimulated whole saliva and stimulated parotid saliva were assessed for flow rate, pH, and buffer capacity using 2 methods. Results showed that calculus status was not significantly associated with caries, but that there was a high association between gingivitis and plaque status with calculus accumulation (P < 0.001). There were no significant differences in saliva flow rate, pH, or buffer capacity between calculus and noncalculus groups. The lack of association between calculus status and caries indicated these 2 conditions have different etiologies and suggests the importance of plaque and calculus prevention programs, in addition to caries control efforts, to maintain oral health of Thai children.