Healing of periodontal connective tissues following surgical wounding and application of citric acid in dogs.

Abstract

Topical application of citric acid to a root surface which has been scaled and root planed results in exposure of collagen fibrils of the dentin matrix. The purpose of this study was to examine the healing of gingival connective tissue adjacent to a root planed and subsequently acid conditioned root surface and to determine whether the exposure of dentin or cementum matrix collagen would facilitate the reestablishment of an attachment between the healing connective tissue and the root surface. Full thickness flaps were raised and labial alveolar bone removed over maxillary incisor roots of seven Labrador retrievers. The exposed root surface was planed before etching with citric acid (pH 1) for 3 min. The flap was then repositioned at its original level. Block sections were obtained after 7, 14, 21 and 42 days and the interface between the root surface and the healing wound tissue studied by light and electron microscopy. Compared to conventional flap surgery in the same animals, application of citric acid to the instrumented root surface resulted in an improved rate of connective tissue healing as well as a rapid and consistent reestablishment of connective tissue attachment through extensive interdigitation of new and old collagen fibrils at the tooth‐gingiva interface. Subsequent reinforcement of the established connective tissue attachment included recalcification of the acid‐affected dentin and deposition of new cementum.