Efeito do reforço com fibra de polietileno na sensibilidade pós-operatória de restaurações Bulk-fill em cavidades profundas: um ensaio clínico randomizado com análise interina

Abstract

Objective: The objective of this double-blind randomized clinical trial was to evaluate the effect of incorporating polyethylene fiber at the base of posterior bulk-fill restorations on postoperative sensitivity (POS). Methods: A total of 58 restorations in deep cavities (≥ 4 mm) were randomized into two groups (n=29): Control (conventional bulk-fill) and Experimental (bulk-fill with polyethylene fiber). POS was measured using the VAS and NRS scales at 24 h, 48 h, 7, and 14 days. A planned interim analysis was conducted after the inclusion of 50% of the total projected sample (n=58), aiming to monitor immediate clinical efficacy. Results: Baseline characterization confirmed group homogeneity regarding all evaluated demographic and clinical variables (age, sex, tooth type, location, presence of cracks, and restorative history; p>0.05). The results indicated that immediate pain intensity (24 h) was similar between groups (p>0.05). However, a significant difference in recovery kinetics was observed: at 48 hours, the experimental group presented lower pain levels on the NRS scale (p=0.029) and a strong clinical trend toward a lower absolute risk of sensitivity (10.3% vs 34.5%; p=0.056). Multivariate analysis revealed that postoperative pain was not influenced by sex, tooth type, or arch, but showed a significant correlation with dental substrate factors: advanced age (p=0.026), replacement of amalgam restorations (p=0.040), and the presence of structural cracks (p=0.033) were predictors of greater pain intensity. Conclusion: Preliminary data suggest that polyethylene fiber promotes a significantly faster symptomatic resolution. The clinical trial will continue until the final sample (n=110) to confirm the findings and assess longevity.