Can Flowable Bulk Fill Composites be Used in Proximal Area of Class II Restorations

This is a Treatment clinical trial, randomized, controlled, parallel, double-blinded, with two groups, that aims to evaluate the best application strategy when using a flowable bulk fill composite (Opus Bulk Fill Flow APS, FGM, Brazil) in class II cavities. Volunteers will be selected and recruited, following inclusion criteria and pre-established exclusion criteria. All volunteers will be informed and sign a term of clarification and consent. All 38 enrolled patients will receive 76 Class II dental restorations, made in two different ways, one from each experimental group. All patients must have at only 20 teeth in function, must have at only 2 carious lesion in proximo-occlusal face in posterior teeth or old restorations in the same faces, with problems, that need to be changed. Those lesions must be more than 3 mm deep in occlusal area and more than 5 mm deep in at only one proximal area, 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. Proximo-occlusal lesions will receive the self-etch adhesive system Ambar Universal APS with selective acid etching, according to the manufacturers instrucions. Then, 2 different restorative protocols will be performed divided in two groups. Group Bulk Flow Proximal (BP): Opus Bulk Fill Flow APS resin will be used in the bulk technique with up to 5mm depth increments, leaving 1 mm in the occlusal for incremental Vittra APS composite resin, that will be used with the traditional incremental technique. Both composites will be light-cured with VALO light-cure unit (Ultradent, USA) for 40 seconds; Group Incremental Proximal (IP): Initially, proximal wall will be completely restored with Vittra APS composite resin, using the triangular incremental traditional technique described for classe II restorations. Then, Opus Bulk Fill Flow APS will be used in the bulk technique with up to 5mm depth increments, leaving 1 mm in the occlusal for incremental Vittra APS composite resin, that will be used with the traditional incremental technique. Both composites will be light-cured with VALO light-cure unit (Ultradent, USA) for 40 seconds. Immediate post-operative tooth sensitivity will be evaluated after one week. Restorations will be evaluated every 6 months for pain assessment, shape, fractures, staining, or recurrent caries, using scores. To determine in which group each tooth will be enrolled, the authors will randomize the teeth.

Inclusion criteria

• Volunteers must have at only 20 teeth in function
• Volunteers must have at only 2 carious proximo-occlusal lesions, or old restorations that need to be changed, in different teeth
• These lesions must be more than 3 mm deep in the oclusal area and more than 5 mm deep in the proximal area, should have exposed dentin, and must have at only 50% of margins in enamel
• Teeth should not present periodontal mobility

Exclusion criteria

• Volunteers with periodontal disease
• Volunteers with gingival bleeding
• Volunteers that have uses anti-inflammatory drugs in the last 30 days
• Pregnant volunteers