Evaluation of Calcium Hydroxide Paste, Mineral Trioxide Aggregate and Formocresol as A Direct Pulp Capping in Primary Molars. Randomized Controlled Clinical Trial

The pulp is imperiled by many environmental impacts. Caries, trauma, restorations, and mechanical injury during cleaning, all are possible aggressions that may injury the pulp tissue. When lesion disrupt enamel barrier, dentin can be degraded by Gram-positive bacteria, such as actinomyces, lactobacilli, and streptococci, that largely dominate the microflora of carious lesion. Pulp response differs according to the degree of the insult. The inflammatory reaction can cause permanent damage or be followed by repair, as the pulp cells have the ability to differentiate into odontoblasts forming dentin matrix facilitating wound healing.

Calcium hydroxide was introduced to the dental practice in the 1920s, and early clinical studies using it in direct pulp capping showed an 80-90 percent success rate.Recent studies with longer follow-up periods suggest lower success rates for it.Calcium hydroxide was used in many forms alone and mixed with other materials for many applications in the dental profession. For direct pulp capping calcium hydroxide powder and aqueous paste were used at first then premixed and cement-based types were developed.

Mineral trioxide aggregate (MTA) was introduced to the dental practice in the 1990s as a root-end filling material. MTA is used as a gold standard in endodontics and has a variety of applications such as root-end filling, apexification, root and truck perforations, apexogenesis, pulp capping in permanent and primary teeth, and dressing for pulpotomy in primary teeth. It is mainly composed of tricalcium silicate, tricalcium aluminate, dicalcium silicate, bismuth oxide, and calcium sulfate dehydrate.

Several studies have shown the efficacy of direct pulp capping using calcium hydroxide and MTA in permanent teeth. However, its use in primary teeth is controversial and few studies are available regarding that subject. Formocresol is not known to be used in direct pulp capping techniques, however, its high clinical success in pulpotomy techniques for primary teeth promoted the investigation of its possible use as direct capping medicament. In addition, there are not enough collected clinical and histological data about direct capping in primary teeth to assess the true success of treatment. Accordingly, the study was directed to evaluate the histological and clinical success of different materials in direct pulp capping for primary teeth.