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

ABSTRACT

Introduction: Use of autopolymerising resin for directprovisionalization is one of the commonest methodsemployed by clinicians. However, these materials exhibit anexothermic reaction and are prone to cause pulpal damage.Thus, a combination of cooling technique and matrix materialto reduce the quantum of heat transferred to a healthy vitalpulpal tissue may be employed for minimal tissue damage.An ex-vivo study was thus envisaged to compare the efficacyof various matrix materials and cooling techniques on timerelated temperature changes in the pulp chamber duringthe fabrication of provisional FPD restorations using directtechnique.Material and Methods: A total of 100 provisionalrestorations were fabricated and were grouped on the basisof three different matrices Vacuum template, Putty index andAlginate index and further subgrouped on the basis of variouscooling techniques employed. Thermal changes in the pulpchamber was evaluated using Cr/ Al thermocouple placedin the pulp chamber of a prepared tooth and connected to adigital thermometer. Intrapulpal temperature variations wererecorded, tabulated and statistically analysed.Results: The inter-group and intra-group statisticalcomparisons of continuous variables were done using analysisof variance with Bonferroni’s correction for multiple groupcomparisons considering the independent study groups. Theunderlying normality assumption was tested before subjectingeach variable to t test and ANOVA. In the entire study, thep-values less than 0.05 were considered to be statisticallysignificant. All the hypotheses were formulated using twotailed alternatives against each null hypothesis (hypothesis ofno difference). The entire data was statistically analysed usingStatistical Package for Social Sciences (SPSS ver 21.0, IBMCorporation, USA) for MS Windows.Conclusion: The order of heat dissipation for the differentmatrices used is as follows Irreversible hydrocolloid matrix >PVS putty matrix > vacuum form template. It was concludedthat intrapulpal temperature rise during the direct fabricationof provisional restorations can be limited by employingdifferent cooling techniques. “Cooling” of PVS putty andalginate 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.