The aims of this study is to demonstrate that not all the lost of dental structure is caused by acid neither the abrasivity of tooth brushing nor the toothpaste. Abfraction is called the wedge-shaped lesion in the Cement-enamel Junction (CEJ) caused by eccentric occlusal forces that lead to the tooth bending. An injury strictly of the cervical enamel that rebounds in dentine and cementum that causes the dental flexion in where periodontium plays an important role. Although the processes of lost of dental structure are due to multifactorial causes, the action of the para funcional forces is acting in one or several pieces of the same sector. During the development of the present study, different causes are mentioned and the reasons why not all the aetiology of non carious cervical lesions, are the response to the action of acids. When the harmful force that generates the loss in wedge shape is present, the structure of the enamel is open giving rise to acid elements that become risk factors to trigger a greater loss of dental structure.