ABSTRACT
Introduction: The aim of this study was to evaluate the composite surface treated by different powers of Erbium-Doped Yttrium Aluminum Garnet [Er:YAG] laser in comparison with bur preparation via scanning electron microscope. Methods: Fourteen composite resin blocks with 15× 10 × 10 mm dimensions were used in this study. The samples were divided to seven groups as follow: Group 1 [power: 1 W, Energy: 50 m/l]; Group 2 [power: 2 W, Energy: 100 m/l]; Group 3 [power: 3W, Energy: 150 m/l]; Group 4 [power: 4 W, Energy: 200 m/l]; Group 5 [power: 5W, Energy: 250 m/l]; Group 6 [power: 6 W, Energy: 300 m/l]; Group 7: Diamond bur. Then, the samples were prepared for SEM examination. Results: The surface treated by Er:YAG laser showed irregular and micro porous surface. Conclusion: It seems that composite surface treatment by Er:YAG laser can be an alternative method for composite repair if suitable parameters are used
ABSTRACT
Recent use of lasers for porcelain surface treatment for adhesion of brackets to restorations has not only showed some promising results, but is also accompanied with less undesirable effects among other advantages. The purpose of this study is the comparative electron microscope evaluation of feldspathic porcelain surfaces under irradiation by Neodymium-Doped Yttrium Aluminium Garnet [Nd:YAG] with different powers [0.75, 1.5 and 2W] via the acid etching with hydrofluoric acid [HF] technique. The glazed porcelain samples were obtained by duplicating labial surfaces of maxillary central incisor teeth. The specimens were randomly treated by 4 different methods. Group1 was etched with hydrofluoric acid 9.6%. Samples in group 2 to 4 were also irradiated by Nd:YAG laser with different powers: 0.75, 1.5 and 2W. Then the samples were prepared for evaluation by scanning electron microscope [SEM]. Etching quality from a porosity point of view was similar for group2 and HF group. Laser with power of 0.75W has little potential to create mechanical porosity. In regard of the results of this study, it is possible to benefit from Nd:YAG laser with appropriate parameters for surface conditioning
ABSTRACT
Tooth pain and sensitization are the two main causes of discomfort after periodontal flap surgery. Effects of low level laser therapy for reducing pain have already been established; these kinds of lasers have been used for tooth desensitization as well. This controlled blind study sought to compare tooth pain and sensitization after 660nm laser irradiation in a split mouth and also in a control group after periodontal flap surgery. Forty patients were enrolled in this study. In these entire patients periodontal flap surgery was done in the upper anterior segment. In the test group, by tossing of a coin the left or right side was determined for laser irradiation, so central incisor, lateral incisor and canine were irradiated by swiping motion of 660nm laser [AZOR, Russia] 25mW, 4.5 J, and 3 min every other day starting one day after surgery; and in collateral segment a placebo probe was put to blind the patients. In the control group, dressing was used after surgery. One, 3, 5 and 7 days after surgery for both groups visual analog score [VAS] for tooth pain and sensitization were recorded for both sides in each patient. In the laser group, both sides had lower VAS for pain than the control group [P< 0.05] after the first day. There was no statistical difference in the laser group between laser irradiated, or non-irradiated segment and for sensitization between groups. Pain can be reduced after periodontal surgery by using low level 660nm laser therapy. Lower pain in both sides in the laser group may be the result of the spread of mediators and neurotransmitters secreted after laser irradiation, or may be because of scattered radiation in the collateral part