Avaliação do laser Er:YAG como condicionador de esmalte e dentina para procedimento de união a materiais resinosos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

The purpose of this study was to verify: 1) the energy levei that could produce the morphologic aspect similar to dental tissues conditioned with phosphoric acid on dental tissues irradiated by Er:Y AG (Yttrium aluminium gamet Y ~L5012) laser; 2) the tension bond strength of an adhesive system applied over enamel and dentin, after pretreatment with phosphoric acid or Er:YAG laser, using the energy levei established on the morphologic analysis. Four third human molars, extracted for orthodontic reasons, were used to make the morphologic analysis. The teeth had their crowns separated from the roots and than, each crown were sectioned in two. The buccal surfaces in enamel, were irradiated with Er:YAG laser, under water cooling, in seven different spots. The following energy levels were used for each spot of irradiation: 60, 100, 160, 200, 300, 400 and 500 mJ. The lingual dental surfaces were prepared with diamond burs, under water cooling, in order to expose dentin substrate, and afterwards were irradiated in the same way described for enamel. After 48 hours, the samples were sputtered with gold and observed under scanning electron microscope. For the tension bond strength test, 40 third human molars had their crowns separated from the roots and were than included in auto activated acrylic resin in plastic cylinders, with 20 mm in outside diameter by 20 mm high, with the occlusal surface facing up. The resin cylinders with the dental portions were randomly separated in four groups of 10 samples each, according to the dental tissue and conditioning method to be used. After, the samples were polished, under water, in a horizontal polishing machine with sandpaper 220, 400, 600, 800 and 1000 grito The samples surfaces were examined under esthereoscopic lens, to assure that on the test region would be exposed only enamel or dentin, depending on the experimental group they belong. In order to obtain the samples for the tension bond strength test, a device idealized by ISO were used, with the purpose of getting a perfect alignment during the bonding procedure. Groups 1 and 3 had their surfaces irradiated with Er:Y AG laser, energy levei of 100 mJ, chosen from the results obtained in morphologic analysis; and the samples of groups 2 and 4 were conditioned with 35% phosphoric acid, for 15 seconds. The adhesive system used, for ali test groups, was Single Bond (3M) and the resin 2-250 (3M), according to manufacturer s instructions. The tension bond strength test was realized 24 hours after the bonding procedure, in a universal test machine Instron model 4411, with a cross head speed of 0,5 mm/min. The results were submitted to Tukey s test at a significance levei of p<0.05. From the results, the mean values of bond strength to enamel and dentin irradiated with Er:Y AG laser were statistically lower (p<0.05) than those for phosphoric acid conditioning. The mean values of bond strength to enamel were statistically higher (p<0.05) compared with dentin, no matter which type of conditioning method used

ASSUNTO(S)

materiais dentarios adesivos dentarios adesão

ACESSO AO ARTIGO

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