Temperature rise during polymerization of resin-based materials to primary teeth

Objective: to assess in vitro the thermal alterations occurred during the applications of resin based materials in primary teeth. Methods: crowns of primary molars were randomly assigned to 3 groups according to the technique performed: I – a resin-based pit-and-fissure sealant (Fluroshield) was applied to the occlusal enamel; II – cavities 3-mm long and 2-mm wide were prepared removing the occlusal enamel and restored in a bulk resin increment; III – cavities 3-mm long and 2-mm wide were prepared leaving a 1-mm-thick remaining dentin and restored in two increments. Specimens of groups II and II were restored with an adhesive agent (Single Bond) and a composite resin (Z250). The tested materials were applied and light cured (using a light-emitting diode – LED) for 20s. Thermocouples were adapted to the roof of the pulp chamber. The temperature rise was considered during both adhesive agent and resin light curing at two moments: from initial to the highest value, and from the highest until return initial value. Results: a descriptive analysis revealed that temperatures rises of up to 9.1oC, 8.6oC and 13.2oC for groups I, II, and III, respectively. Conclusions: resin photopolymerization causes high temperatures values, even in a sealant technique, outstanding the heat accumulated during the restorative procedure in primary teeth. Therefore, clinicians should be aware of the potential thermal hazard to the primary tooth pulp, which might be resulted from light curing of resin-based materials.