Histological evaluation of mineral trioxide aggregate and calcium hydroxide in direct pulp capping of human immature permanent teeth.

PURPOSE: To evaluate histological findings in human immature permanent premolars scheduled for extraction for orthodontic reasons, in which mechanical pulp exposures were capped with white ProRoot Mineral Trioxide Aggregate (WMTA) or calcium hydroxide (CH).

METHODS: Forty-eight human immature premolars in 23 patients (age 10-18 years) were randomly treated with WMTA or CH. After rubber dam isolation Cl I cavities were prepared and the pulps exposed. After hemostasis the pulps were capped with either material. The preparations were restored using an acid etch, bonding agent, flowable composite and composite resin technique. The teeth were extracted after 47 to 609 days and processed for routine histological examination, stained with hematoxylin and eosin and Brown and Brenn for recognition of bacteria. Statistical analyses of inflammation, bridge formation and bacterial leakage were performed using a Chi-square test and ANOVA.

RESULTS: Forty-four of 48 teeth were suitable for microscopic evaluation, 30 with WMTA, 14 with CH. Of the WMTA group, 29 teeth were vital, 28 had formed a bridge, and one specimen had failed. Twelve of 14 teeth with CH were vital, while three teeth failed to form a bridge. No statistically significant differences between WMTA and CH were found, except for superficial and deep inflammatory cell response (P < or = 0.05). Pulp capping of intentionally exposed human immature premolars performed slightly better when using MTA.