Regional bond strengths of adhesive resins to pulp chamber dentin

Microleakage of oral microorganisms, which can occur due to the lack of sea ling ability of permanent restorative materials, may cause failure of root canal treatments. Although a great deal of research has been done on sealin g enamel and coronal dentin with resins, little research has been done on t he adhesion of resins to the walls of pulp chambers. The purpose of this st udy was to evaluate regional bond strengths of two adhesive systems to the walls of pulp chambers. A section was made horizontally through the middle of the pulp chamber of extracted human third molars to divide the chamber i nto upper and lower halves. The pulp tissue was removed and the tooth segme nts were then divided into treatment subgroups. The pulp chambers were bond ed with C&B Metabond (Parkell) or One-Step (Bisco), with or without 5% NaOC l pretreatment. The microtensile bond strengths of these resins to four dif ferent pulp chamber regions (bottom, wall, roof, and pulp horn areas) were then measured using an Instron machine. The data were expressed in MPa and were analyzed by a three-way ANOVA. Statistically significant differences w ere found among the test groups (p < 0.001). One-Step produced higher bond strengths to all pulp chamber regions except the floor, compared with C&B M etabond. The results indicated that high bond strengths can be achieved bet ween adhesive resins and the various regions of the pulp chamber. This shou ld permit the use of a thick layer of unfilled resin along the floor of the pulp chamber and over the canal orifices as a secondary protective seal af ter finishing root canal therapy.