Comparative histologic analysis of coronally advanced flap with and without collagen membrane for root coverage

Guided tissue regeneration (GTR)-based root coverage has been utilized to correct gingival recession defects with promising results. However, limited histologic information is available. Therefore, the aims of this study were to clinically and histologically evaluate the efficacy of GTR-based root coverage using collagen membrane (GTRC) and to compare the healing response to that of coronally advanced flaps (CAF).

Standardized gingival recession defects were surgically created on the labial surfaces of the maxillary cuspids of 8 mongrel dogs. Plaque was allowed to accumulate for 8 weeks to develop a plaque-infected recession defect. Full-mouth scaling and root planing was then performed coincident with 4 weeks of oral hygiene. Defects were randomly assigned to receive either GTRC or CAF surgery. Four dogs each were sacrificed at 4 and 16 weeks post-treatment. Clinical measurements included: percent root coverage, the amount of keratinized gingiva (KG), and probing depth (PD). Sulcular depth, junctional epithelium and connective tissue attachment, new cementum formation, and new bone formation were evaluated histomorphometrically.

Clinically, both treatments (CAF and GTRC) achieved statistically significant (P <0.05) root coverage compared to baseline. KG was significantly increased in CAF-treated sites at 16 weeks, while no significant differences were found for other clinical parameters between treatments. Histometrically, GTRC showed a statistically significant increase of new attachment and newly formed connective tissue when compared to CAF at 16 weeks.

Within the limits of this preclinical study, both GTRC and CAF can be successfully used for the treatment of gingival recession defects.