ABSTRACT
The purpose of this study was to evaluate histopathologically the effect on pulp tissue of microleakage in resin composite restorations. Seventy-two class V cavities were prepared on buccal surfaces of monkeys and divided into 3 groups, F, O, and S. Every cavity was etched with 37% phosphoric acid. In group F cavities, each cavity was restored with photo-curable composite without any dentin adhesives. In group O, the cavities were left unfilled. In group S, each cavity was treated with a dentin adhesive system and restored with a restorative composite. After 3, 30, or 90 days, animals were sacrificed and the subjected teeth were immediately removed, then fixed and decalcified. Following sectioning and staining with hematoxylin and eosin or Taylor's modified bacteria staining, each sample was examined with a light microscope. In most teeth with group S cavities, bacterial invasion was not found indicating excellent marginal sealing. The pulpal reaction was much less than that in other groups. In group F as well as in group O, bacteria were frequently observed in the cavity; however, bacteria penetrated into dentinal tubules more in group F than in group O at 30 and 90 days. A correlation between the presence of bacteria and pulpal inflammation was strongly indicated. It was suggested that a leaky restoration was more harmful to the pulp than an open prepared cavity without restoration.
Subject(s)
Composite Resins/chemistry , Dental Leakage/pathology , Dental Pulp/pathology , Dental Restoration, Permanent , Acid Etching, Dental , Analysis of Variance , Animals , Bacteria/classification , Coloring Agents , Dental Cavity Lining , Dental Cavity Preparation/classification , Dental Marginal Adaptation , Dental Pulp/microbiology , Dental Restoration, Permanent/classification , Dentin/microbiology , Dentin/pathology , Dentin, Secondary/pathology , Dentin-Bonding Agents/chemistry , Fluorescent Dyes , Macaca , Methacrylates/chemistry , Odontoblasts/pathology , Phosphoric Acids/chemistry , Pulpitis/microbiology , Pulpitis/pathology , Resin Cements/chemistry , Statistics as Topic , Surface Properties , Time FactorsABSTRACT
PURPOSE: To evaluate the bond strengths of three different types of resin bonding systems to teeth prepared for endodontic treatment. MATERIALS AND METHODS: Access cavity preparation and removal of pulpal tissue were performed in bovine incisors. The root canals were chemically irrigated with saline (control), 5% sodium hypochlorite, 3% hydrogen peroxide, or combinations of both for 60 s. After storage in water for 1 d, the dentin surface was ground to a flat surface with 600-grit SiC under water. The area for bonding was demarcated with a vinyl tape (4 mm-in-diameter hole), and bonded using either Clearfil Liner Bond II, Single Bond, or Superbond C&B. After storage in 37 degrees C water for 1 d, tensile bond strengths were measured using a universal testing machine at a crosshead speed of 2 mm/min. Ten teeth were tested for each group. RESULTS: One-way ANOVA and Fisher's PLSD test revealed that Single Bond and Superbond C&B had a statistically lower (P < 0.05) bond strengths in the chemical irrigation groups compared with the control group.
