This study aimed to evaluate the clinical performance of a novel vitro-ceramic biomaterial (Biosilicate®) as treatment of caries-affected dentin in posterior resin restorations. A total of 94 restorations of 66 participants were selected and assigned at random into four groups: 1 (Biosilicate / Two-step etch and rinse system), 2 (Control / Two-step etch and rinse system), 3 (Biosilicate / Two-step self-etching system) and 4 (Control / Two-step self-etching system). Two operators carried out the adhesive protocols and restored the cavities with a nano-hybrid resin composite (IPS Empress, Ivoclar) using the incremental technique. Participants were recalled at one week, 6, 12 and 18 months for clinical evaluation performed by two blinders and calibrated examiners according FDI criteria.

Background: Dental caries has decreased in recent years, but is still the main oral health problem in developed and undeveloped industrialized countries. The purpose of this study is to evaluate clinical performance of resin-based composite Class I and II restorations in association with Biosilicate.

Methods: Eighty patients with carious lesions will be receive restorations in premolars and molars, which will be randomly allocated in four experimental groups: G1 (Biosilicate, AdperSingle Bond 2 and IPS Empress Direct composite), G2 (Adper Single Bond 2 and IPS Empress Direct composite), G3 (Biosilicate, AdheSe and IPS Empress Direct composite) e G4 (AdheSE and IPS Empress Direct composite) To participate in the clinical trial, qualified subjects must meet for inclusion and exclusion criteria. Sixty-four (64) selected volunteers will be fully informed on the nature of the study and after had signed a Term of Acceptance defined by the Ethics Committee (FORP - USP), they will be invited to participate.

Carious teeth will be cleaned with a pumice-water slurry and rubber cup to remove salivary pellicle and any bacterial plaque. As much as possible, local anesthesia will be. After caries removal (high and low-speed handpieces under abundant water irrigation), patients will be allocated randomly in the four experimental groups cited above. Final contouring and polishing of the restorations will be performed at the same appointment, using a fine-grit diamond bur (KG Sorensen), silicon carbide polisher (Viking Kit, KG Sorensen), silicone rubber tips (Viking Kit, KG Sorensen) flexible discs (Sof-Lex, 3M ESPE), and polishing pastes (Diamond Excel, FGM).

Two trained and calibrated evaluators, fully blinded to the restorative techniques used, will be evaluating the restorations at baseline (one week after placement of restorations), after 06, 12 and 18 months using FDI criteria. All restorations will be photographed at every evaluation point. Esthetic, Functional and Biological proprieties will be used as key parameters determining the overall clinical success. Data will be analyzed.

Inclusion Criteria:

• Cavitated or non-cavitated active carious lesions in dentin (Class I and/or II)
• Carious lesion in teeth with or without restoration in at least one tooth (upper or lower premolar and/or molar).
• No history of spontaneous pain
• Pulp vital tests positive
• No evidence of periapical radiolucency

Exclusion Criteria:

• Compromised medical history
• Periodontal disease
• Pulp necrosis
• Absence of antagonist teeth
• Severe bruxism
• Active orthodontic treatment
• Teeth with cracks and premature contact.
• Pregnancy