Pulpal reactions to the application of citric acid to root-planed dentin in beagles

The purpose of this study was to examine histological reactions in the dental pulp incident to the application of citric acid to a root-planed tooth surface. Full thickness flaps were raised and the labial alveolar bone removed over maxillary and mandibular incisor roots in six beagles. The exposed root surfaces were subjected to either superficial or deep root planning. On either the right or left side in each dog, citric acid (pH 1) was applied to the root surfaces for 3 min. The flaps were then repositioned at their original level. Block sections of mandibular teeth were obtained at one week and of maxillary teeth at fifteen weeks after experimental procedures. Histological examination of the short-term specimens showed a reduced width of the predentin corresponding to the instrumented root surface, but no cellular reactions in the odontoblast layer or the pulp. At 15 weeks, varying amounts of reparative dentin had formed in all specimens. More reparative dentin had formed after deep root planing than after superficial, while the difference between acid-conditioned and non-acid conditioned teeth was nonsignificant. The results indicate that root planing may result in the formation of reparative dentin but does not cause inflammatory cellular reactions in the pulp. The application of citric acid to the root planed surface does not significantly change the character of the histological pulpal response.