Potential hazards associated with photocuring dentin bonding agents

Summary form only received as follows: Light sources used to cure dental restorative materials have improved greatly with many of them having intensities approaching 800 mW/cm². Because of the increased light intensity, the potential for exposing pulpal tissues to elevated temperatures is greater. The objective of this study was to measure the temperature rise associated with curing a dentin adhesive ProBond (Caulk Dentsply, Milford, DE) and a composite Z-100 (3M, St. Paul, MN) using an Optilux Model 401 light curing unit (Demetron Research Corp., Danbury, CT). The experimental set up consisted of a stainless steel mold having a diameter of 6 mm x 3 mm depth placed over a mylar strip and a type J thermocouple. The assembly was held at 37°C. Three sets of measurements were taken in triplicate for the conditions: A) no material; B) bonding agent; C) bonding agent + 2 mm composite. Temperatures were recorded after exposure to the light for 10, 20, 30 and 40 seconds and are given in a table. The temperature increase was significant for each group. The largest temperature increase was 42.5°C when no material was present. Placement of the bonding agent gave a maximum temperature increase of 31.6°C while curing of the composite gave only a 9.5°C increase due to its ability to act as an insulator. These results suggest that curing of bonding agents in deep restorations may expose the dentin surface to significant temperature increases even though the light source may be 3 mm from the exposed surface