This randomized clinical randomized double blind, and split mouth design trial, approved by the Committee for Ethics in Research of the local university, in accordance with the number of protocol (pending number). It was registered at Rebec identification number (pending number) and held in full corresponding with the Declaration of Association Medical world of Helsinki [18]. All the volunteers signed the term of consent free and clear and the study was conducted in the Center Specialty Dental location Jan to March in 2018, and ratings made on local University the period from January 2019 to February of 2020.
Sample
The participants of this study were patients between 18 and 60 years, who attended the service dental in Center Specialties Dental of (pending name of city) and were met by a professional specialist this service.
For the calculation sampling, the first resulting was calculated on the basis of previous study [19], considering a 15% rate of success in the most posterior restorations resin, a power of 0.8, and a level of significance of 0, 05. Over more, a 20% of loss in follow-up was n = 50 restorations (2 for each patient).
Criteria of eligibility
To be included in the study, patients had to have the presence of at least two molars with caries interproximal to be restored with Class II; occlusal contact with the healthy antagonist tooth or with direct restorative material; and in good state of health overall. Patients with chronic disease with oral manifestations were excluded from the study; habits of bruxism, pulp exposure during the removal of caries or cavities with imminent risk of pulp exposure; patients with teeth that would be used as pillars for dentures removable or partial fixed.
Allocation, groups, and blinding
The teeth that met the criteria for inclusion were distributed randomized by means of envelopes sealed to establish in which group each tooth would be allocated, the following way:
Group I (experimental) - G1: Opus Bulk Fill FGM composite resin. Group II (control) - G2: conventional composite resin Opalis FGM.
The study was double-blind (patient and evaluator blind), split mouth, equal allocation between the groups.
Clinical procedure
Before restoration, all patients responded to the quality of life questionnaire (OHIP-14) [21], were instructed by researchers on proper hygiene to maintain oral health, and an X-ray was taken of all selected teeth with the generic Hyena Dentistry positioner. After removing of the affected tissue with low-rotation burns and dentin, isolation and selection of enamel conditioning with 37% acid phosphoric acid (Condac, FGM - Joinville - Brazil) was performed for 30 seconds, then washed with jet of water and dried with absorbent paper. The universal system adhesive (Ambar, FGM, Joinville,
Brazil) was actively applied and light-cured for 20 seconds with the Radii Cal lamp (SDI, Bayswater, VIC, Australia) with intensity measured at 1,000 mW / cm2.
Group I (experimental): The Unimatrix steel matrix (TDV) was inserted to then start the fabrication of the restoration with Opus Bulk Fill (FGM, Joinville, Brazil) composite resin in increments of up to 4 mm. First, the proximal walls were made at the level of the marginal ridge of the neighboring tooth. Each increment was photoactive for 20 seconds and then ended with the occlusal box.
Group II (control): The Unimatrix steel matrix (TDV) was inserted to then start the fabrication of the restoration with composite conventional Opalis (FGM, Joinville, Brazil) by the technique incremental with increments of up to 2 mm. First, the proximal walls were made up to the height of the marginal ridge of the neighboring tooth. Each increment of up to 2 mm, was light cured for 20 seconds with Radii Cal lamp and then made the box occlusal also in of 2 mm increments.
At the end of the restorations, it was achieved the proper adjustments with paper carbon contact (Angelus, Londrina, Brazil) and finishing and polishing to high speed.
Clinical evaluation of restorations
The evaluation of the restoration was done by two evaluators calibrated and blinded to the type of material, at Baseline, 12 and 24 months after realization, based on criteria clinical the evaluation (Alpha, Bravo Charlie), proposed by the United States Public Health Service (USPHS) [20] ( Table 2 ).
Interproximal and periapical radiographs were used for the evaluation during the returns. The sensitivity was evaluated in the application of an air jet with the triple syringe for 5 seconds on the restored teeth.
The clinical time spent in minutes for each group after preparation of the cavity was also assessed and tabulated, that is, precisely the time spent in the insertion and photopolymerization of the restorative material.
Assessment of patients Quality of Life (QoL)
For the evaluation of the quality of life (QoL) related to oral health, were used the questionnaire Oral Health Impact Profile in a resumed version (OHIP-14) validated for the local idiom, (ref pending) with a total of 14 questions answered by the patient in the period reference before treatment and 12 months after treatment.
Statistical Analysis
The statistical analyzes followed the protocol of intention to treat according to the suggestion of CONSORT (Consolidated Standards of Reporting Trials ) [21]. A descriptive statistical analysis of the groups was carried out, highlighting the relative frequencies of each score. The independent variables were: type of resin (Bulk Fill and conventional), the evaluation time (12 and 24 months) for all items (dependent variables): retention, restoration staining, discoloration marginal, marginal adaptation, secondary caries, surface texture, anatomical shape and thermal sensitivity. After verifying that the data did not have a normal distribution (Shapiro-Wilk, p > 0.05), the Kruskal Wallis test was used to test the hypothesis if there was a statistically significant difference between the groups in relation to the dependent variables.
For the analysis of the clinical time spent on the restorative procedure, the data were tabulated and, because they had a normal distribution, the T- student test was applied.
For the analysis of the questionnaires the total OHIP-14 score, a quantitative analysis methodology was used, in order to explore the behavior of a group through the QoL before and after 12 months after the restorative procedure, so the questions were divided into domains ( Table 3 ) and since the data did not show a normal pattern, the Wilcoxon test was applied .
Statistical analyzes were performed using SPSS 24.0 software (IBM company, SPSS Statistic, USA), with a 5% significance was considered.