This systematic review compared the effects of multiple pulp capping materials on hard tissue formation. A total of 51 citations were identified and published between August 1, 2000 and December 21, 2017 using the PubMed, Cochrane, Embase, and Summon databases. After exclusion criteria were applied by 2 of the authors and discrepancies mediated by a third author, 27 articles were included in the systematic review and the meta-analyses were conducted on 22 studies. Inclusion criteria were permanent teeth with mechanical exposures undergoing pulp therapy, use of commercially available materials for pulp capping, use of calcium hydroxide (CH) as a control material, histologic evaluations performed on extracted teeth, reported outcome as dentin bridge formation, and a minimum follow-up of 30 days.
Key Study Factor:
Of the 27 studies included in the systematic review, 20 were controlled clinical trials and 7 were randomized clinical trials (RCTs). The meta-analysis included a total of 190 teeth that used mineral trioxide aggregate (MTA) compared to 142 teeth that used CH and then 161 teeth that used a bonding agent versus 93 that used CH.
Main Outcome Measure
The main positive outcome measure was histological observation of a completely formed dentin bridge a minimum of 30 days after performing pulp capping treatment. A negative outcome was considered a histological result showing anything less than a complete dentin bridge formation beyond the minimum 30-day postoperative healing period.
The study evaluated 3 different materials in 2 separate analyses of each material’s ability to form dentinal bridges after mechanical pulp exposures. Using MTA resulted in a higher rate of dentinal bridge formation versus CH. The odds ratio (OR) of dentinal bridge formation with MTA versus CH was 2.45 (95% confidence interval [CI], 1.39 to 4.29; P =.002). Compared against CH, bonding agents yielded fewer positive outcomes of dentinal bridge formation. The OR of the bonding agent−induced dentinal bridge versus CH was 0.02 (95% CI, 0.01 to 0.05; P < .001).
MTA was more effective than CH at hard-tissue barrier formation, and MTA had better effects than CH in capping mechanical pulp exposures. The use of a bonding agent as a pulp capping material produced inferior results compared to CH. More RCTs with larger sample sizes should be conducted to further strengthen these conclusions, and future studies should also test the quality of dentinal bridges formed, not only the positive or negative presence.