Estudo das propriedades mecânicas da interface adesiva criada por sistemas adesivos convencional e autocondicionante, associados ou não ao laser Nd:YAG, utilizando a técnica da nanoindentação

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação da resistência de união em dentina submetida ao desafio erosivo: adesão ao substrato tratado com CPP-ACP e irradiado ou não com laser Nd:YAG

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Resistência de união de um sistema adesivo irradiado com laser Nd:YAG em dentina tratada com laser de Er:YAG

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Soldagem em laminas finas de hastelloy c-276 por laser pulsado Nd:YAG

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influência do laser Nd:YAG na qualidade da hibridização da dentina bovina empregando sistema adesivo convencional ou autocondicionante: análise em MEV

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito do laser de Nd:YAG do fluoreto de sódio na prevenção da erosão em dentina bovina através de perfilometria

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito da aplicação de sistemas adesivos autocondicionantes associados ao laser Nd:YAG na prevenção do desgaste erosivo/abrasivo do esmalte dental

Pós-graduação em Odontologia Restauradora - ICT

Efeito do laser Nd:Yag no pré-tratamento dentinário e selamento marginal, em restaurações de cimento de ionômero de vidro resina modificado

Pós-graduação em Odontologia Restauradora - ICT

Influência do espaçamento do feixe de laser Nd: YAG na obtenção de óxidos e nitretos na superfície do titânio em pressão atmosférica

Neste trabalho investigou-se a modificação de superfície do titânio pela irradiação com feixe de Laser Nd:YAG. Os parâmetros do laser como a potência, o comprimento de onda, a frequência, a velocidade de varredura e a área de exposição foram mantidos constantes, exceto o espaçamento da matriz, o qual foi de 0,01 e 0,02 mm. A caracterização da superfície foi realizada por Microscopia Eletrônica de Varredura (MEV) e Difração de Raios X (DRX), sendo que os espectros foram refinados pelo método Rietveld. Pela análise de MEV, observou-se uma mudança na topografia, obtendo uma superfície rugosa produzida pelo fenômeno de ablação. As análises por Rietveld dos espectros de difração de raios X detectaram TiN, Ti2N, TiO2 (anatásio e rutilo), sendo que a amostra com espaçamento 0,01 mm apresentou uma maior quantidade de óxidos e nitretos. Isso pode ser devido à sobreposição do feixe, induzindo à formação de uma superfície com maior estabilidade termodinâmica. Os óxidos e nitretos obtidos são de grande importância, pois são responsáveis por produzir uma maior interação entre o osso-implante.

Influence of Nd:YAG or Er:YAG laser surface treatment on microtensile bond strength of indirect resin composites to resin cement. Lasers surface treatment of indirect resin composites

This study evaluated the influence of the surface pretreatment of indirect resin composite (Signum, Admira Lab and Sinfony) on the microtensile bond strength of a resin cement. Sixty samples made of each brand were divided into 6 groups, according to surface treatment: (1) control; (2) controlled-air abrasion with Al2O3; (3) Er:YAG Laser 200 mJ, 10 Hz, for 10s; (4) Er: YAG Laser 300 mJ, 10 Hz, for 10 s; (5) Nd:YAG 80 mJ, S15Hz for 1 min; (6) Nd:YAG 120mJ, 15 Hz for 1 min. After treatments, all the groups received an application of 37% phosphoric acid and adhesive. The pair of blocks of the same brand were cemented to each other with dual resin cement. The blocks were sectioned to obtain resin-resin sticks (1 x1 mm) and analyzed by microtensile bond testing. The bond strength values were statistically different, irrespective of the surface treatment performed, with highest values for Sinfony (43.81 MPa) and lowest values for Signum (32.33 MPA). The groups treated with the Nd:YAG laser showed the lowest bond strength values and power did not interfere in the results, both for Nd:YAG laser and Er:YAG. Controlled-air abrasion with Al203 is an efficient surface treatment method and the use of the Nd:YAG and Er:YAG lasers reduced bond strength, irrespective of the intensity of energy used.

Effect of Nd:YAG Irradiation and Fluoride Application on Dentine Resistance to Erosion in Vitro

Objective: In this paper we evaluated the effect of two fluoridated agents and Nd:YAG irradiation separately and in combination on dentine resistance to erosion. Background Data: The morphological changes in dentin induced by laser treatment may reduce the progression of erosive lesions. Due to the possibility of a synergistic effect of laser with fluoride, this study was conducted. Materials and Methods: Eighty bovine dentine samples (4 x 4 mm) were randomly divided into eight groups, according to the following treatments: G1: untreated (control); G2: acidic phosphate fluoride gel (APF 1.23%) for 4 min; G3: fluoride varnish (NaF 2.26%) for 6 h; G4: 0.5 W Nd: YAG laser (250 mu sec pulse, 10 Hz, 35 J/cm(2), 30 sec); G5: 0.75 W Nd: YAG laser (52.5 J/cm(2)); G6: 1.0 W Nd: YAG laser (70 J/cm(2)); G7: APF + 0.75 W Nd: YAG laser; and G8: NaF + 0.75 W Nd: YAG laser. After the treatments, half of each dentine surface was protected with nail varnish. The samples were stored in artificial saliva (30 mL/sample) for 24 h and submitted to four erosive 1-min cycles. Between the erosive attacks, the blocks were maintained in artificial saliva for 59 min. The erosive wear was evaluated by profilometry. Results: The mean wear (+/- SD, mu m) was: G1: 1.20 +/- 0.20; G2: 0.47 +/- 0.06; G3: 0.81 +/- 0.11; G4: 1.47 +/- 0.32; G5: 1.52 +/- 0.24; G6: 1.49 +/- 0.30; G7: 0.49 +/- 0.11; and G8: 1.06 +/- 0.31 (Tukey's test, p < 0.05). Conclusions: Laser irradiation was not able to reduce dentine erosion. However, fluoride application was able to increase the dentine's resistance to erosion, and APF showed better results than fluoride varnish.

Effects of Nd : YAG and Er : YAG lasers on the sealing of root canal fillings

Objective: the ability of the laser irradiation to promote the cleaning and disinfection of the radicular canal system has become this type of treatment in a viable and real alternative in endodontics. The purpose of this study was to evaluate the apical marginal sealing of root canal fillings after the irradiation with the laser of Nd:YAG or of Er:YAG. Materials and Methods: Forty-two human, extracted single-rooted teeth had their crowns sectioned and the root canals prepared with a no. 70 K-file. Then, they were dried and divided into three groups according to canal wall treatment: group 1: the canals were filled with EDTA for 3 min, followed by irrigation with 1% sodium hypochlorite solution; group 2: the canal walls were irradiated with Nd:YAG laser; and group 3: the canal walls were irradiated with Er:YAG laser. Afterwards, the root canals were obturated by the lateral condensation technique. The roots were externally waterproof, except in the apical foramen and immerged in 2% methylene blue aqueous solution during 48 hours. Results: the results showed that the largest infiltrations happened in the group 3-Er:YAG (7.3 mm), proceeded by the group 1-EDTA (1.6 mm) and by the group 2-Nd:YAG (0.6 mm). The group Er:YAG differed statistically of the others (p < 0.05). Conclusion: It was concluded that the Er:YAG laser intracanal irradiation previously to the root canal filling must be used with caution until future research is define the best parameters for it's use.

Effect of dental surface treatment with Nd:YAG and Er:YAG lasers on bond strength of resin composite to recently bleached enamel

The aim of this work is to evaluate the effect of surface treatment with Er:YAG and Nd:YAG lasers on resin composite bond strength to recently bleached enamel. In this study, 120 bovine incisors were distributed into two groups: group C: without bleaching treatment; group B: bleached with 35% hydrogen peroxide. Each group was divided into three subgroups: subgroup N: without laser treatment; subgroup Nd: irradiation with Nd:YAG laser; subgroup Er: irradiation with Er:YAG laser. The adhesive system (Adper Single Bond 2) was then applied and composite buildups were constructed with Filtek Supreme composite. The teeth were sectioned to obtain enamel-resin sticks (1 x 1 mm) and submitted to microtensile bond testing. The data were statistically analyzed by the ANOVA and Tukey tests. The bond strength values in the bleached control group (5.57 MPa) presented a significant difference in comparison to the group bleached and irradiated with Er:YAG laser (13.18 MPa) or Nd:YAG (25.67 MPa). The non-bleached control group presented mean values of 30.92 MPa, with statistical difference of all the others groups. The use of Nd:YAG and Er:YAG lasers on bleached specimens was able to improve the bond strengths of them.

Evaluation of the shear bond strength of a composite resin in sound, demineralized and hypermineralized bovine dentin after irradiation with Er:YAG and Nd:YAG lasers, employing a self-etching adhesive system

Background and Objectives. The adhesion of dental materials is important for the success of treatment. The aim of this study is to evaluate the bond strength of a composite resin applied with a self-etching adhesive system in different dentins after irradiation with Er:YAG and Nd:YAG lasers, observing their morphologic pattern using Scanning Electronic Microscopy (SEM). Materials and Methods. The buccal surface of 72 bovine incisors was worn until exposure of medium depth dentin. The specimens were divided into three groups; GI: normal, GII: demineralized and GIII: hypermineralized dentin. These were also divided into two subgroups; A-irradiated for 30 s with Er:YAG laser in noncontact mode at 40 mJ and 6 Hz and B- irradiated for 30 s with Nd:YAG laser in contact mode at 60 mJ and 10 Hz. The adhesive system Clearfil SE. Bond (Kuraray) and composite resin Tetric Ceram (Vivadent) were applied on the irradiated area by the incremental technique. After storage for 24 h in distilled water at 37 degrees C, the specimens were submitted to the shear strength test in a universal testing machine (EMIC) at a crosshead speed of 1.0 mm/min. Other specimens were made to be analyzed by SEM. Results. The results were statistically analyzed by Analysis of Variance and the Tukey test. Regardless of the type of dentin, the bond strength of specimens irradiated with the Nd:YAG laser (8,94 +/- 2,07) was higher compared to specimens irradiated with the Er:YAG laser (7,03 +/- 2,47); the highest bond strength was obtained for the group of hypermineralized dentin irradiated with the Nd:YAG laser. The SEM analysis showed that the Er:YAG laser caused opening of tubules and the Nd:YAG laser produced areas of fusion as well as regions of opening of dentinal tubules. Conclusions. The dentin showed different morphological patterns and the laser promote alterations on their surfaces, influencing the bond strength of the composite resin. (C) 2010 Laser Institute of America.

Resistência à cárie de esmalte dental irradiado por lasers de Er:YAG e Nd:YAG, avaliada através da morfologia e proporção Ca/P

Pós-graduação em Ciências Odontológicas - FOAR