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    Effects of Different Combinations of Er:YAG Laser-Adhesives on Enamel Demineralization and Bracket Bond Strength
    (Mary Ann Liebert, Inc, 2016) Cokakoglu, Serpil; Nalcaci, Ruhi; Usumez, Serdar; Malkoc, Siddik
    Objective: The purpose of this study was to investigate the demineralization around brackets and shear bond strength (SBS) of brackets bonded to Er:YAG laser-irradiated enamel at different power settings with various adhesive systems combinations. Methods: A total of 108 premolar teeth were used in this study. Teeth were assigned into three groups according to the etching procedure, then each group divided into three subgroups based on the application of different adhesive systems. There were a total of nine groups as follows. Group 1: Acid + Transbond XT Primer; group 2: Er:YAG (100 mJ, 10 Hz) etching + Transbond XT Primer; group 3: Er:YAG (200 mJ, 10 Hz) etching + Transbond XT Primer; group 4: Transbond Plus self-etching primer (SEP); group 5: Er:YAG (100 mJ, 10 Hz) etching + Transbond Plus SEP; group 6: Er:YAG (200 mJ, 10 Hz) etching + Transbond Plus SEP; group 7: Clearfil Protect Bond; group 8: Er:YAG (100 mJ, 10 Hz) etching + Clearfil Protect Bond; group 9: Er:YAG (200 mJ, 10 Hz) etching + Clearfil Protect Bond. Brackets were bonded with Transbond XT Adhesive Paste in all groups. Teeth to be evaluated for demineralization and SBS were exposed to pH and thermal cyclings, respectively. Then, demineralization samples were scanned with micro-CT to determine lesion depth values. For SBS test, a universal testing machine was used and adhesive remnant was index scored after debonding. Data were analyzed statistically. Results: No significant differences were found among the lesion depth values of the various groups, except for G7 and G8, in which the lowest values were recorded. The lowest SBS values were in G7, whereas the highest were in G9. The differences between the other groups were not significant. Conclusions: Er:YAG laser did not have a positive effect on prevention of enamel demineralization. When two step self-etch adhesive is preferred for bonding brackets, laser etching at 1 W (100 mJ, 10 Hz) is suggested to improve SBS of brackets.
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    In-vitro assessment of temperature rise in the pulp during orthodontic bonding
    (Mosby-Elsevier, 2010) Malkoc, Siddik; Uysal, Tancan; Usumez, Serdar; Isman, Eren; Baysal, Asli
    Introduction: In this in-vitro study, we evaluated the temperature changes in the pulp chamber during bracket bonding using 4 different light sources. Methods: Eighty intact extracted maxillary central incisors were used. The teeth were divided into 4 groups of 20 teeth each. Brackets (Mini Twin, Dentaurum, Ispringen, Germany) were bonded with Transbond XT (3M Unitek, Monrovia, Calif) adhesive and light cured with low-intensity halogen light for 40 seconds, high-intensity halogen light for 40 seconds, light-emitting diode (LED) light for 20 seconds, and plasma arc light (PAC) for 6 seconds. Light curing was performed 5 mm from tooth surfaces. A J-type thermocouple wire was positioned in the center of the pulp chamber. The results were analyzed with analysis of variance (ANOVA) and the Tukey HSD test. Results: ANOVA and the Tukey HSD test showed that pulp chamber temperature changes were influenced by the type of light source. All groups showed significant differences between each other (P <0.001). The intrapulpal temperature changes induced by different light sources were the following: high-intensity halogen (6.84 degrees C +/- 2.44 degrees C), low-intensity halogen (4.71 degrees C +/- 0.96 degrees C), LED (2.95 degrees C +/- 1.12 degrees C), and PAC (0.96 degrees C +/- 0.83 degrees C). Conclusions: High-and low-intensity halogen light induced significantly higher intrapulpal temperature changes than did the LED and PAC. Except for the high intensity halogen light, orthodontic bonding with light-curing units did not exceed the critical 5.5 degrees C rise in temperature reported to produce pulpal damage. (Am J Orthod Dentofacial Orthop 2010; 137: 379-83)