In vitro assessment of the role of air spray on pulp temperature changes for preheated resin composite Class V restorations in lower incisor

To evaluate the effect of 15- and 30-psi air spray on in vitro pulp temperature (PT) during light-curing of buccal Class V restorations in lower incisors using preheated resin composites (RBCs). After ethical approval, a Class V cavity was prepared in a sound lower central incisor. A T-type thermocouple was inserted into the pulp chamber and connected to a temperature measurement system (Thermes WiFi, Physitemp). Simulated pulpal fluid flow was maintained at a rate of 0.001 mL/min. Real-time PT and working time were recorded during restoration with Viscalor Bulk-fill (VOCO) and Filtek One Bulk-fill (Solventum) preheated to 68 °C. Air spray (15 or 30 psi) was directed to the lingual surface, starting 3 s before and maintained throughout light-curing (n = 9). Vickers hardness (VHN) was measured at the middle and inner surfaces near the top and bottom of each specimen. PT and VHN data were analyzed using nonparametric mixed ANOVA, and working time was analyzed using nonparametric two-way ANOVA, both followed by Bonferroni's post hoc tests (α = 0.05). Light-curing of preheated RBCs significantly increased PT (42.5 ± 1.3 °C; p < 0.001). Air spray at 15 and 30 psi reduced PT values (28.4 ± 1.3 °C and 26.8 ± 1.8 °C, respectively; p < 0.001) without affecting VHN values. Air spray during light-curing effectively minimized pulp temperature rise during restorative procedures using preheated RBCs on lower incisors.