1. The means by which two objects are fastened together.
2. A mechanical device used to retain or stabilize a dental prosthesis. The epithelial attachment is the biological mechanism that joins the junctional epithelium to the tooth. It is formed from the reduced enamel epithelium. The junctional epithelium forms the hemidesmosomal attachment of the gingival tissues to the teeth. The attachment apparatus includes the periodontal ligament, the cementum, and the alveolar bone. The clinical attachment level is the distance from the attachment of the periodontal tissues (junctional epithelium and gingival fibres) at the base of the gingival crevice or sulcus (attachment level) to a fixed point on the tooth, usually the cemento-enamel junction measured with a periodontal probe. With the development of chronic periodontitis, there is destruction of the crestal alveolar bone and apical migration of the crestal gingival fibres and junctional epithelium (loss of attachment). New attachment refers to connective tissue fibres attaching to previously diseased periodontal root surface; this is a desirable outcome following periodontal surgery. A precision attachment is a prefabricated appliance used to retain a bridge or partial denture (fixed or removable prosthesis).