In vitro study of the microleakage in cavities submitted to treatment with Er:YAG laser and restored with aesthetic materials

O objetivo desse estudo foi avaliar, in vitro, a microinfiltração marginal em cavidades de classe V submetidas ao tratamento com laser de Er:YAG e restauradas com materiais estéticos. Foram selecionados 60 dentes humanos e realizados preparos de classe V no terço cervical das faces vestibular e lingual. A técnica restauradora seguiu as especificações dos fabricantes. Os dentes foram divididos em três grupos de 20 dentes: Grupo 1 (controle), Grupo 2: procedeu-se previamente à restauração um tratamento com laser de Er:YAG na superfície do esmalte do ângulo cavo-superficial, Grupo 3: antes da restauração, aplicou-se uma fina camada de cimento de Ca(OH)2 na parede axial. Cada grupo foi dividido em quatro subgrupos e restaurados com materiais estéticos diferentes. Todos os dentes foram submetidos a ciclagem térmica e técnica de infiltração com nitrato de prata a 50%. Com base nos resultados, concluiu-se que existem diferenças entre as doze condições experimentais realizadas. As amostras que apresentaram maior microinfiltração foram, em primeiro lugar, as com tratamento com laser de Er:YAG e restauradas com cimento de ionômero de vidro fotoativado. Em segundo, as tratadas com laser de Er:YAG e restauradas com a técnica do sanduíche (cimento de ionômero de vidro convencional + resina composta fotoativada). Em terceiro, as restauradas com cimento de ionômero de vidro fotoativado, e por último as restauradas com a técnica do sanduíche.The aim of this in vitro study was to evaluate marginal microleakage in class V preparations submitted to treatment with Er:YAG laser and restored with aesthetic materials. Sixty human molars were selected and class V cavities were prepared on the buccal and lingual aspects of their cervical thirds. The restorative technique followed the instructions of the manufacturers. The samples were divided in 3 groups of 20 teeth each: Group 1 - control; Group 2 - Er:YAG laser was applied on the enamel margin before the restoration was placed; Group 3 - a thin layer of calcium hydroxide was applied on the axial wall before the restoration was placed. Each group was divided in 4 sub-groups and the teeth were restored with different aesthetic materials. All samples were submitted to thermocycling and stained with 50% silver nitrate. Based on the obtained results, we could conclude that there are statistically significant differences between the 12 experimental conditions tested. The samples which presented the greatest microleakage were those treated with Er:YAG laser and restored with light-cured glass ionomer cement, followed by those that received Er:YAG laser and the sandwich technique, the cavities restored with light-cured glass ionomer cement and those restored by means of the sandwich technique, in this order