Asymmetry of caries attack on the occlusal surfaces of first permanent molar teeth

A bstract — In a retrospective study of the records of 510 final‐grade primary school children, caries experience in the occlusal surfaces of homologous right‐left pairs of first permanent molar teeth was analysed. It was 44.4 per cent of maxillary, and 32.6 per cent of mandibular pairs of surfaces showed unilateral caries experience. The initial caries attack in pairs of surfaces with bilateral caries experience occurred at a significantly earlier age than in the group with unilateral caries experience (p<0.001). In addition, the interval following the initial attack during which the remaining tooth in each pair remained sound was analysed. Highly significant differences were found between the groups with unilateral and bilateral caries experience ( p < 0.001 ). The findings have implications for the design of investigations using the half‐mouth technique.