Non carious cervical lesions. A review.

Non-carious cervical lesions (NCCL) are characterized by a loss of hard dental tissue near the cement-enamel-junction. Commonly, their shape is like a wedge with the apex pointing inwards. Other times, they appear as regular depressions, like a dome or a cup. Their main characteristic is the presence of hard-mineralized tissue. According to the literature, the prevalence of cervical lesions is 85%, while their incidence is about 18% among permanent teeth. NCCL are currently classified as erosion, abrasion, or abfraction. Their etiology seems to be related to different factors: hexogen and endogen acids, mechanical abrasive action, tooth flexion under axial and non-axial loads. Moreover, it seems that a fundamental role is ascribable to tooth bending phenomena due to the strength components parallel or oblique to the occlusal level, which occur during the normal function as well as during parafunctions. The frequent therapeutic failures are probably due to the same factors causing the onset of the original lesion. Several materials have been proposed to restore NCCL: amalgam (abandoned), glass-ionomer cements, compomers, and composite resins. Early failures of these restorations have often been reported in the literature, probably due to the same factors which originally caused the lesions. Further investigations are required to determine more reliable restorative therapies.