Can the Use of a Warm-Air Stream for Solvent Evaporation Lead to a Dangerous Temperature Increase During Dentin Hybridization?

Purpose: To analyze the effect of a warm-air stream for solvent evaporation on the temperature rise in the pulp chamber during dentin hybridization. Materials and Methods: Dentin disks with thicknesses of 0.5, 1.0 and 1.5 mm were obtained from extracted human molars. A model tooth was set up with the dentin disks between a molar with an exposed pulp chamber and a crown with an occlusal preparation. A K-type thermocouple connected to a digital thermometer was placed in the molar root until it entered the pulp chamber and made contact with the dentin disks. After 10 s of adhesive application, solvent evaporation was performed for 10, 20, 30, and 40 s and the increase in temperature was monitored for 200 s after the warm-air stream began. Results: The temperature increase was significantly influenced by the thickness of the dentin disks (0.5 mm = 1.0 mm > 1.5 mm). With respect to the duration of the warm-air stream, the temperature increase was as follows: 10 s 20 s 30 s 40 s (p 0.05). The highest temperature was found after 40 s with dentin disks that were 0.5 mm (16.6°C) and 1.0 mm (15.8°C) thick, whereas the lowest temperature increase occurred after 10 s with a dentin disk that was 1.5 mm thick (4.1°C) (p 0.05). Conclusion: The temperature in the pulp chamber was strongly influenced by the dentin thickness and the duration of the warm-air stream. Thinner dentin and a longer duration of the warm-air stream both lead to a greater temperature increase in the pulp chamber. Keywords: dentin bonding, warm-air stream, pulp chamber temperature increase