Determination of subepithelial connective tissue graft thickness in the dog

Abstract

Purpose: In this study, we determined the tissue thickness of healed subepithelial connective tissue grafts, the type of tissue present after healing, and the percentage of shrinkage of subepithelial connective tissue grafts over time in the facial aspect of the canine maxilla. Materials and Methods: Four dogs each received 2 single-thickness subepithelial connective tissue grafts, 2 double-thickness grafts, and 2 sham-operated sites in the facial aspect of the maxilla bilaterally. The subepithelial connective tissue graft was harvested from the palate and included the periosteum. After the creation of a pouch on the facial aspect of the maxilla, the grafts were sutured directly to the maxillary periosteum and additional sutures were placed to secure the overlying mucosal flap to the graft. Thickness measures of the grafts before placement and after surgery with the grafts in place were made biweekly with a calibrated probe using known reference points on the teeth. Thickness measures were analyzed using a random-effects mixed model. All dogs were killed at 12 weeks, and the tissues were fixed, serially sectioned, and stained with hematoxylin and eosin for microscopic examination. Results: Initial measurements of the sites demonstrated a thickness of 1.5 ± 0.6 mm. Immediate postoperative measures were 7.1 mm (single thickness), 7.0 mm (double thickness), and 4.8 mm (sham operated). Week 6 measures were 3.9 mm (single thickness), 3.6 mm (double thickness), and 2.7 mm (sham operated), and week 12 measures were 3.9 mm (single thickness), 3.4 mm (double thickness), and 2.9 mm (sham operated). The difference between single- and double-thickness grafts was not significant (P =.34). The differences between single thickness and sham operated (P =.0036) and between double thickness and sham operated (P =.0049) were significant. Microscopic evaluation demonstrated that the grafts were indistinguishable from the adjacent subcutaneous tissues of the maxilla. The submucosal graft region contained fat, small blood vessels, nerves, and fibrous connective tissue. Conclusions: Based on this study in dogs, shrinkage of subepithelial grafts can be expected. The grafts become incorporate into the host tissues and appear similar to the normal connective tissue. © 2002 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 60:415-421, 2002