Clinical Evaluation of Different Application Strategies When Using a Universal Adhesive System in Class V Cavities

This is a Treatment clinical trial, randomized, controlled, parallel, double-blinded, with four groups, that aims to evaluate the best application strategy when using a new Universal Adhesive system, Ambar Universal (FGM, Joinville, Brazil). Volunteers will be selected and recruited,following inclusion criteria and pre-established exclusion. All volunteers will be informed and sign a term of clarification and consent. All 38 enrolled patients will receive Class V dental restorations, made in four different ways, one from each experimental group, using the same universal self-etching adhesive system, which is the tested material in this study. All patients must have at only 20 teeth in function, must have at only 4 non carious cervical lesions (NCCL), in different teeth, that need restoration. Those lesions must be non carious, must be more than 1 mm deep, should have exposed dentin, and must have at only 50% of margins in enamel. Teeth should not present periodontal mobility. Firstly, the patient will be anesthetized locally with 3% Mepivacaine solution, followed by prophylaxis with pumice powder and water. All cavities will be washed and dried after these procedures for optimal selection of color, using a color scale. Then, the rubber dam isolation of the teeth to be restored will be held. Non-carious cervical lesions will receive the applied adhesive system in 4 different protocols separated by groups. Group SET (control): no conditioning, the adhesive system will be used in 55 teeth, according to the manufacturer's instructions, in the self-etching mode. The adhesive system will be brushed during 10 seconds in the cavity, will be air-dried during 5 seconds, brushed again during 10 seconds, air-dried during 10 seconds and activated during 10 seconds with LED light; Group SEE (Selective enamel etching): 37% phosphoric acid will be applied during 15 seconds, only in enamel in 55 teeth. This acid will be removed using water, the cavity will be air-dried, and then, the adhesive will be applied according to the manufacturer's instructions, as described in group SET; Group SETT: Similar to Group SET, but during the 2 applications, the adhesive systems will be brushed during 20 seconds, and not during 10 seconds as described in Group SET; Group SETL: The adhesive system will be applied as describe in Group SET, but the researchers will apply 4 layers, and not 2 layers, as described in Group SET. After applying the adhesive, the restorations will be made with composite resin Opallis (FGM, Joinville, Brazil), and evaluated every 6 months for pain assessment, shape, staining or recurrent caries, using scores. To determine in which group each tooth will be enrolled, the authors will randomize the teeth.