A surgical technique involving a resorbable membrane was used to treat 3 to 7 mm localized human buccal recessions on 10 consecutive patients. The exposed root surface was scaled and a trapezoidal mucoperiosteal flap was elevated after de-epithelization of the papillae. The space between the root and the membrane was created using a bur to form a concavity on the root and by bending the membrane with a suture. The flap was positioned as coronally as possible covering the membrane. The sutures were removed 15 days postsurgery and tetracycline therapy prescribed for 10 days. The results were evaluated at 12 months. The surgical procedure resulted in a significant reduction in recession (2.9 mm +/- 1.3) as well as a gain in attachment (3.4 mm +/- 2.1). Calculation of mean root coverage was 59.6%. There was no significant change of the keratinized tissue width. For therapeutic reasons, re-entry was performed in 2 cases: newly formed tissue was observed on the previously exposed roots. Guided tissue regeneration using a resorbable membrane appears to provide good results in cases of localized buccal recession.

The substitution of the internal enamel epithelium by a squamous epithelium during tooth eruption has been studied histologically in rat molars. Just prior to eruption, cytolysis of the connective tissue covering the cusp tip determines hyperplasia in the oral epithelium. A conspicuous infiltration results. Infiltrated undifferentiated cells form distinct cords which seem to be attracted by the internal enamel epithelium. They reaggregate when they come into its contact and form an underlying epithelium. The process starts in the superficial part and progressively extends towards the cervix. Finally, the internal enamel epithelium is expelled when desquamation begins. The lack of mitoses in both stratum intermedium and internal enamel epithelium and the pyknosis observed in the former, clearly show that the cells of the embryonic dental bell do not take part in the formation of the squamous epithelium as some authors still suppose.