The Incidence of Pulp-healing Defects with Direct-capping Materials

Objectives: The purpose of this work was to: (a) Study the injury and healing activity of the pulp tissue to calcium hydroxide [Ca(OH)2], composite resin (CR) and resin-modified glass ionomer (RMGI) materials when used as direct pulp capping agents (b) Compare the incidence of healing defects in response to these materials. Methods: Class V pulp exposed cavities (n = 135) were prepared in non-human primate teeth. Direct pulp capping was conducted over 7 to 730 days with hard set [Ca(OH)2], RMGI and CR materials. Healing defects recorded were: (1) Bacterial leakage detected with McKays stain (2); Operative debris including dentin fragments and particles of capping material (3); Pulpal inflammatory activity evaluated according to ISO and FDI standards (4); Area and continuity of tertiary dentin bridge formation and (5) presence of tunnel defects in bridge. Statistical analysis was evaluated using Analysis of Variance tests (P values). Results: The capping materials were associated with varying levels of pulp healing defects, including tunnel defects (P = 0.0001); operative debris (P = 0.0001); pulpal inflammatory activity (p = 0.0073) and bacterial microleakage (P = 0.0260). Other healing defects and the area of dentin bridge were not influenced by capping materials (P > 0.05). Greater numbers of pulp healing defects were associated with Ca(OH)2 in comparison with RMGI or CR materials. Conclusions: Pulp healing defects have some relationship with treatment failure, but the general lack of information on material-pulp interactions remains problematic. The success of direct pulp capping will be optimized by using new CR materials, or RMGI, rather than Ca(OH)2 to reduce the incidence of pulp healing defects.