J Oral Laser Applications 8 (2008), No. 1 (18.03.2008)
Quantification of Polymerization Using Er:YAG Laser Ablation Techniques
Jacomassi, Denis P. / Rastelli, Alessandra Nara S. / Bagnato, Vanderlei S.
Purpose: The aim of this study was to evaluate the efficacy of polymerization of composite resin photocured with different wavelengths and irradiation times by means of ablation techniques with Er:YAG laser.
Materials and Methods: A microhybrid composite resin was photocured with argon laser (Coherent, Innova 200-20) at 400 mW/cm2 for 15, 40, 60, 300, and 900 s. The wavelengths used were 476.5, 488.0, 502.7, and 514.5 nm. The samples were ablated with Er:YAG laser at three energy levels (100, 200, and 300 mJ), a fixed frequency of 2 Hz, and water flow of 0.12 ml/s for 10 s. The ablated volume was measured to quantify polymerization. Two-way ANOVA and Tukey's test were used to analyze the data.
Results: The results showed a more effective polymerization for the wavelength of 476.5 nm with low irradiation times (15, 40 and 60 s). Longer photoactivation (300 and 900 s) and a wavelength of 488.0 nm resulted in less ablation.
Conclusion: The ablation techniques with Er:YAG laser can be used for evaluation of efficacy of polymerization of the composite resin and showed that the wavelengths of 476.5 and 488.0 nm provided the best polymerization rate.
Keywords: photocuring, composite resins, argon laser, Er:YAG, ablation rate