The principle of restorative dentistry is maintenance of a healthy and functional pulp-dentin complex which would allow successful healing of the exposed pulp. Pulp exposures can be either mechanical or carious. If such exposure occurs in vital and reversibly damaged pulp, direct pulp capping (DPC) can be performed to maintain the coronal and radicular pulp in viable condition. In clinical studies, the outcome of such vital pulp treatments is typically considered successful when the patient is symptom free, and there are no signs of apical periodontitis and the tooth reacts to sensibility tests, thus showing signs that pulpal health has been preserved12. If successful, this procedure precludes the need for more invasive, more extensive and more expensive treatment like root canal treatment or extraction (5).
The status of the pulp at the time of exposure is an important parameter determining the successful outcome of the procedure. Pulp capping prognosis appears to be more favourable in teeth with mechanical pulp exposures(studies). The data from literature revealed a controversy regarding the outcome of DPC in carious pulp exposures. Historically, DPC has been considered doubtful in mature permanent teeth with carious pulp exposures and instead root canal treatment was recommended(1-5 in Bogen). Barthel et al reported a success rate of only 13% in cariously exposed pulp. The potential reason for inferior results might be the residual microbes in the surrounding dentinal tubules that have chance to penetrate into pulp spaces, subsequently leading to pulp necrosis and apical periodontitis(Barthel, Stanley, Langeland). In addition, during caries excavation, bacteria may be inadvertently forced into the pulp which was already inflamed due to deep carious lesion(Caicedo). However, some recent studies reported higher success rates even in carious pulp exposures, provided the inflammation is no more severe than reversible pulpitis(studies). A recent review by Aguilar and Linsuwanont, and cost effective analysis by Schwendicke and Stolpe provides evidence that mature permanent teeth with carious pulp exposures might be managed successfuly by DPC. Bogen et al reported a high success rate of 97.96% for pulp capping in carious exposures.
Previous studies emphasizes that numerous parameters are capable of influencing the success rate of DPC. Pulp capping material is important one of them. Calcium Hydroxide (CH) has been considered as gold standard, against which all other materials suggested for pulp capping are judged4. Clinical success rates were reported to vary considerably from 13% – 97.8%. CH is involved in pulp repair and dentin remineralization2. Also, it possesses antibacterial properties which can minimize or eliminate bacterial penetration and subsequent irritation of pulpal tissue2. However, several disadvantages have been listed with use of CH, including lack of sufficient sealing, biocompatibility5, non adhesive2, dissolution over time, multiple tunnel defects and porosities in dentin bridge formed6. These might be responsible for the variable results that have been reported in relation to the use of this material7, 8.
Recently, Mineral Trioxide Aggregate (MTA) has been investigated as a material for DPC. The success rates of direct pulp capping were reported to range from 67.4% – 97.96% for MTA. MTA induces dentin bridge formation10, possesses superior sealing, biocompatibility6, excellent marginal adaptation, maintain high pH for longer duration11, and close physiochemical seal between dentin and MTA that provide insoluble barrier against micro leakage5.
Most of the previous investigations that compared CH and MTA as pulp capping materials used healthy intact teeth that might not show the real clinical condition in which teeth with deep caries have inflamed pulp prior to treatment. Till date, only two randomized clinical trials have evaluated the effectiveness of CH and MTA as direct pulp capping materials. But, these were multicentric trials which obviously have an inherent limitation of lack of monitoring of ongoing study procedures.
Another important parameter of clinical assessment is postoperative pain following direct pulp capping. To date, only 2 studies have evaluated the postoperative pain following direct pulp capping with CH and MTA. Kundzina et al14 assessed postoperative pain with CH and MTA as pulp capping materials 1 week after the procedure and observed that pain was slightly more often in the MTA group than in the CH group but was not significantly different between materials. This finding is consistent with the study by Iwamoto et al18, in which capping healthy pulps with White MTA and CH (Dycal) yielded no difference in postoperative pain. But the results of this study cannot be generalized to carious teeth.
Thus, the aim of the present study was to evaluate the treatment outcome with CH and MTA as direct pulp capping materials in cariously exposed teeth and to assess the association between pulp capping materials and postoperative pain. The null hypothesis stated that there was no difference between the materials evaluated as direct pulp capping materials.