The anatomy of non-carious cervical lesions

The term "non-carious cervical lesion" (NCCL) describes a dental hard tissue defect of unknown origin. Two very distinct variations are known: wedge-shaped and saucer-shaped lesions. Reasons for occurrence of two forms might include different contributing factors. Forty-two teeth, 19 wedge-shaped and 23 saucer-shaped lesions, were analysed by light and confocal laser scanning microscopy (CLSM) to investigate presence of calculus and organic matter, surface structure of the lesion, borders of the lesion, and potential fractures in the dental hard tissues. One hundred percent of the wedge-shaped teeth showed evidence of additional abrasion (incisal/occlusal surface) but only 70 % of the saucer-shaped teeth. In most teeth, the edge was rounded. Tiny grooves parallel to the cemento-enamel junction (CEJ) were present in 11 % of the wedge-shaped and in 39 % of the saucer-shaped lesions. Seventy-nine percent wedge-shaped and 52 % saucer-shaped lesions had some sort of apposition. Eighty-eight percent of all teeth had dead tracts, 62 % of which were located directly next to the defect (in the lesion). In 48 %, sclerotic dentin was present right next to the defect (in the lesion). Tertiary dentin was visible in 60 %. Not a single fracture was detected. Different characteristics associated with each type of cervical lesion support the theory of different aetiology or at least of differing contributions from different factors that participate in the development of NCCLs. Only knowledge of the correct aetiology of NCCLs will allow the best treatment and prevention for such lesions.