Comparative Evaluation of Various Cooling Techniques on Intrapulpal Temperature Rise during Direct Provisionalization - An Ex-vivo Study.

Abstract

Introduction: Use of autopolymerising resin for direct provisionalization is one of the commonest methods employed by clinicians. However, these materials exhibit an exothermic reaction and are prone to cause pulpal damage. Thus, a combination of cooling technique and matrix material to reduce the quantum of heat transferred to a healthy vital pulpal tissue may be employed for minimal tissue damage. An ex-vivo study was thus envisaged to compare the efficacy of various matrix materials and cooling techniques on time related temperature changes in the pulp chamber during the fabrication of provisional FPD restorations using direct technique. Material and Methods: A total of 100 provisional restorations were fabricated and were grouped on the basis of three different matrices: Vacuum template, Putty index and Alginate index and further subgrouped on the basis of various cooling techniques employed. Thermal changes in the pulp chamber was evaluated using Cr/ Al thermocouple placed in the pulp chamber of a prepared tooth and connected to a digital thermometer. Intrapulpal temperature variations were recorded, tabulated and statistically analysed. Results: The inter-group and intra-group statistical comparisons of continuous variables were done using analysis of variance with Bonferroni’s correction for multiple group comparisons considering the independent study groups. The underlying normality assumption was tested before subjecting each variable to t test and ANOVA. In the entire study, the p-values less than 0.05 were considered to be statistically significant. All the hypotheses were formulated using two tailed alternatives against each null hypothesis (hypothesis of no difference). The entire data was statistically analysed using Statistical Package for Social Sciences (SPSS ver 21.0, IBM Corporation, USA) for MS Windows. Conclusion: The order of heat dissipation for the different matrices used is as follows: Irreversible hydrocolloid matrix > PVS putty matrix > vacuum form template. It was concluded that intrapulpal temperature rise during the direct fabrication of provisional restorations can be limited by employing different cooling techniques. “Cooling” of PVS putty and alginate impression index for 2 minutes in refrigerator (Ambient temperature 10-120C) was found to be most effective “cooling” method for preventing temperature rise in pulp.