Comportamento clínico de compósitos de incremento único para restauração de dentes posteriores: estudo clínico controlado e randomizado

Abstract

Introduction: Bulk fill composites is a newly and innovative material in the restorative dentistry field, in addition to reduced clinical time, these composites are able to reduce the polymerization shrinkage stress. Objective: This study evaluated the clinical performance of regular and low (flow) viscosity bulk fill resins under different adhesive strategies, compared to conventional resin, after six months of restoration. Methods: One hundred and fifty-four class I restorations were made on posterior teeth and randomly allocated to the following treatment groups (G): G1 (control 1) – 37% phosphoric acid + conventional three-step adhesive + compactable conventional nanoparticle resin; G2 (test) – 37% phosphoric acid + conventional three-step adhesive + low viscosity/flow bulk fill resin + compactable conventional nanoparticle resin; G3 (test) – 37% phosphoric acid + conventional three-step adhesive + regular viscosity bulk fill resin; G4 (control 2) - System universal adhesives in self-etching mode + compactable conventional nanoparticle resin; G5 (test) – System universal adhesives in self-etching mode + low viscosity/flow bulk fill resin + compactable conventional nanoparticle resin; G6 (test) - System universal adhesives in self-etching mode + regular viscosity bulk fill resin. Two calibrated examiners evaluated the restorations by direct clinical observation. Fédération Dentaire Internationale (FDI) criteria was used for clinical evaluation of restorations. Kruskal-Wallis test was used to compare treatment groups; Wilcoxon test to evaluate each treatment group over time (baseline x 6 months); and MannWhitney test to compare restorative techniques. A significance level of 5% (p<0.05) was adopted. Results: In overall, all groups showed clinically satisfactory results, with differences for surface staining (p=0.012) and anatomical form (p<0.001) at baseline. After 6 months, only the color/translucency parameter (p<0.001) showed difference between the groups. In the comparison over time (after 6 months) there was a significant reduction to color/translucency [G4 (p=0.014) e G5 (p=0.025)] and anatomical form [G4 (p=0.046) e G6 (p=0.025)]; an improvement in marginal adaptation [G5 (p=0.025)], patient satisfaction [G6 (p=0.034)] and reduced postoperative sensitivity [G6 (p=0.010)]. The use of the universal adhesives system in self-etching mode led to a significant reduction (p<0.05) in the clinical performance in terms of color/translucency (p=0.008) and anatomical form (p=0.039), compared to the conventional system. Moreover, the use of bulk fill resin as a base of conventional resin showed a significant reduction (p=0.025) in color/translucency, compared to the use of only regular viscosity bulk fill. Conclusion: Then, in conclusion all the restorative protocols evaluated showed properly clinical performance after 6 months, but promising results was found for the use of conventional three-step adhesive system and regular viscosity bulk fill resin. Long-term studies should be conducted to ensure the quality and clinical performance of proposed materials and techniques.