A laboratory study comparing the effect of ridge exposure using tissue punch versus mucoperiosteal flap on the formation of the implant-epithelial junction.

Objective: The objective of the present study was to clarify the influence of the incision design at the time of implant placement on the consolidation of the implanto-epithelial junction.

Study Design: Twelve minipigs were chosen for the study. Four weeks after premolar extraction in the maxilla, 4 BEGO Semados RI implants were inserted in each quadrant. Using a split-mouth design, the alveolar crest was exposed by a punch ("flapless surgery") on one side and by a crestal incision ("flap surgery") on the other side. Biopsies were obtained from the peri-implant soft tissue at weeks 1, 2, 4, and 12 postinsertion, respectively, and analyzed for the expression of integrin α(6)β(4) chain β(4) (ITGB4) and laminin 5 γ(2) chain (lamc2), 2 important marker molecules for the formation of the implanto-epithelial junction.

Results: Following exposure of the alveolar crest by the punch technique, a significantly higher expression of ITGB4 was found at the 2- (P = .009), 4- (P = .001), and 12-week (P = .005) follow-up. Furthermore, the expression of lamc2 was significantly higher following punch exposure after 1 (P = .033), 2 (P = .041), 3 (P = .004), and 12 weeks (P = .002) of transmucosal implant healing.

Conclusions: The data of the present study indicate that flapless placement improved the formation of a sufficient implanto-epithelial junction.