Role of Anatomic and Salivary Factors in Dental Calculus Formation in Primary and Mixed Dentition Stages.

PURPOSE: Clinical experience shows that formation of calculus is a very rare phenomenon in primary teeth, but it increases as the permanent teeth erupt. The purpose of this study was to assess the relationship between dental calculus, dental anatomy, and salivary factors in primary and mixed dentition stages. METHODS: A cross-sectional study was carried out to determine the buccolingual dimensions of the most concave and the most convex surfaces of the lingual aspect of mandibular central incisor crowns in a sample group of 120 three- to five-old children and 120 eight- to 10-year old children. Saliva samples were collected from 20 in each group. Data were analyzed using t tests. RESULTS: Significant differences were found between the ratio of the buccolingual dimensions of the most convex to the most concave areas of the lingual surfaces in primary and permanent incisors (P=0.028). Saliva analysis revealed significant differences in total protein (P=0.002), sodium (P=0.037), bicarbonate (P=0.003), and ammonia (P=0.025) between the two age groups. CONCLUSIONS: Anatomic and salivary factors may be important reasons for the differences in calculus formation.