It has been suggested that ideal occlusion would contribute to caries prevention, that crowding would predispose teeth to caries, and that enamel defects would increase caries susceptibility. Such opinions usually occur in textbooks or articles without any reference to relevant scientific evidence. Studies have been published that assess the association between occlusal features and caries. The studies reported vary greatly with respect to representativeness and diagnostic criteria. The findings have been conflicting. The most recent studies that have included relatively large numbers of subjects do not confirm an association between occlusal findings and caries experience. Crowding does not seem to increase susceptibility to caries. The suggested association between enamel defects and clinically diagnosed caries has only been studied in deciduous teeth. Defective enamel structure appears to increase caries susceptibility mainly in children whose enamel defects are caused by nutritional problems early in life that affect the whole of the deciduous dentition.