Are Dentists Adequately Curing Resin Composite Restorations?

Method: Data were collected in the UK (Scotland, England, N. Ireland) using MARC® Patient Simulator (MARC® PS, BlueLight™, Halifax, Canada). The dentist or nurse was asked to use their LCU to cure each of two simulated restorations, one anterior, one posterior, as they would under normal clinical conditions using an RBC shade A3 or equivalent. A variety of protective eye wear was supplied and the operator could chose the one normally used. The following data were collected: type of LCU; total curing time (time x no. cycles); maximum irradiance; energy delivered in 420-540nm (blue light); energy delivered in 380-420nm (violet light); time taken to achieve the minimum energy requirement of 16J/cm2.

Result: 213 dentists and nurses took part, using 23 different makes of LCU. Ratio of LED/QTH 70/30; 78% delivered adequate energy (16 J/cm² according to EU) in the time they cured to anterior teeth and 22% to posterior teeth; < 5% increased time or cycles when curing posterior v anterior teeth; only two LEDs delivered more than 2.00 J/cm²in violet range;  > 60% operators chose not to use protective eyewear.

Conclusion: The results suggest that dentists and dental nurses are not fully aware of the fact that their LCUs and practice protocols are not delivering adequate energy when curing their patient’s restorations. Under-curing of restorations is known to lead to premature failure and replacement.