Interposition of a connective tissue graft or a collagen matrix to enhance wound stability – an experimental study in dogs

Abstract

Aim: The aim of this study was to evaluate the role of a connective tissue graft (CTG) or a collagen matrix (CM) interpositioned between flaps and non-shedding hard surfaces on wound stability. Material and Methods: Sixty bone dehiscence defects were prepared in five Beagle dogs. Three treatments were performed in 12 sites per dog: (1) repositioned flaps were sutured onto instrumented dentin surfaces (control), (2) repositioning of flaps with an interpositioned CTG and (3) repositioning of flaps with the application of a CM. To allow postoperative healing with n = 5 for 1, 3, 7 and 14 days before evaluation, the sutures were removed, incision lines retraced and tensile forces applied to the flaps. The minimum magnitude of forces required to detach the flaps from the wound bed was recorded. Results: After 1 week of healing, 6 N had to be applied to disrupt flaps from their wound bed in the CTG group. In the control group, a similar magnitude of resistance was achieved after 2 weeks (6.1 N). Flap resistance to tearing was highest in the CTG group (maximum 9.1 N) 2 weeks postoperatively. On the third postoperative day, the mean tearing forces of all groups differed significantly, displaying a 50% lower resistance to tearing in the CM compared to the CTG group. In comparison, flap resistance to tearing forces established earlier and in higher magnitude in sites with an interpositioned CTG than in flaps repositioned on dentin or CM. Conclusions: Application of a CTG, sutured to a non-shedding hard surface, significantly increased flap resistance to tearing when applying disrupting forces compared to controls. A less pronounced effect was achieved by interpositioning of a CM.