Evaluation of intrapulpal temperature changes caused by bulk-fill composite resins cured with different light-source modes: ex vivo

Abstract

Objective: The aim was to evaluate the effects on intrapulpal temperature change of two different LED light-source modes used during the polymerization of bulk-fill composite resins placed in deep cavities. Materials and Method: Human extracted mandibular molar teeth (n=5) were used to create single-tooth model with an occlusal dentin-thickness of 0.5 mm. Filtek Bulk Fill Posterior (3M ESPE) and SDR (Dentsply) were applied according to manufacturers’ instructions. A conventional composite resin, Filtek Z250 (3M ESPE) was used as control. The soft and turbo modes of LED (Bluephase 20i, Ivoclar Vivadent) were used for polymerization. Intrapulpal temperature changes were determined by using a device simulating pulpal blood microcirculation. For each material, initial and maximum temperature was determined during the curing. Difference between the initial and the highest temperature value was considered as the maximum temperature change (Δt). The data were analyzed with two-way variance analysis and post-hoc Tukey test (p<0.05). Results: The turbo mode was found to cause significantly greater temperature rise than the soft mode (p<0.001; Tukey test). When the filling material was taken as the variable, the greatest temperature change was observed in the SDR, whereas the least temperature change was observed in the control (p<0.05; Tukey test). Conclusion: The polymerization of bulk-fill composite resins in the turbo mode of the LED light-source led to greater pulpal temperature rise. The materials’ content and structure also affected the temperature increase. Using the soft mode of a LED light-source for the polymerization of bulk-fill composite resins in deep cavities is preferable to keep the intrapulpal temperature rise minimum.

Keywords

• Composite resins
• dental pulp
• LED dental curing lights
• temperature