Microshear Bond Strength of Composite Resin to Enamel Treated With Titanium Tetrafluoride and the Carbon Dioxide Laser (10.6 μm): An in Vitro Study

Introduction: the present study aims to assess the microshear bond strength (μsbs) of composite to enamel treated with titanium tetrafluoride (tif_4) and co_2 laser irradiation. methods: fifteen human molars were sectioned and their enamel surfaces were abraded. the sections were randomly assigned to 5 groups (n = 15): (co); control group, (ap); treated with 1.23% acidulated phosphate fluoride (apf) for 4 minutes, (ti); 4% tif_4 for 1 minute, (l+ap); co_2 laser irradiation (10.6 μm wavelength, 1 w peak power, 10 ms pulse duration, 500 ms repetition time, 0.2 mm beam spot size at the tissue level, 2 cm distance of handpiece tip to tissue surface (dse, south cores) followed by 1.23% apf, and (l+ ti); 10.6μm co_2 laser irradiation followed by 4% tif_4 for one minute. using tygon tubes, z250 (3m/espe) composite was bonded to the surface of the samples. the μsbs of composite to enamel was measured using a microtensile testing machine after 500 thermal cycles. the data were analyzed by one-way anova and the tukey hsd test (p < 0.05). results: the mean μsbs was 20.66, 20.21, 13.44, 23.01, and 10.16 mpa in co, ap, ti, l+ap, and l +ti groups respectively. significant differences were observed between co and ti (p = 0.026) and also co and l+ ti (p < 0.0001). conclusion: the application of tif_4 per se and after co_2 laser irradiation on enamel decreased the μsbs of composite to enamel; on the other hand, apf alone and after laser irradiation did not have any adverse effect on the μsbs of composite to enamel.