Effect of ultrasonic activation of endodontic sealers on root canal filling quality during the single-cone obturation procedure: a systematic review and meta-analysis of laboratory-based studies

This review aimed to investigate the potential of ultrasonic activation of sealers in improving the filling quality of single-cone obturation. A systematic search was conducted across 6 electronic databases. Data extraction and quality assessment were performed. Twenty studies were included, with 11 meeting the criteria for meta-analysis. Meta-analyses revealed lower porosity with ultrasonic activation (UA) compared to non-ultrasonic activation (NA), as demonstrated by micro-CT (MD = -1.21, 95% CI: -1.69 to 0.74, I2 = 28%) and stereomicroscopy studies (coronal [MD = -0.05, 95% CI: -0.82 to -0.18, I2 = 0%]; middle [MD = -0.44, 95% CI: -1.56 to 0.68, I2 = 89%]; apical [MD = -0.50, 95% CI: -0.78 to -0.21, I2= 0%]. Confocal laser scanning microscopy analysis showed significantly higher sealer penetration (%) with UA at the apical [SMD = 2.28, 95% CI: 1.17 to 3.40, I2 = 71%] and middle thirds [SMD = 2.69, 95% CI: 1.16 to 4.22, I2 = 87%]. However, studies examining other penetration indicators and push-out bond strength yielded inconsistent results. These findings suggest that ultrasonic activation of sealers positively influences filling quality during single-cone obturation, evidenced by decreased porosity. Further research is required to explain the variations in sealer penetration and bond strength. Ultrasonic activation of root canal sealers has emerged as a promising adjunctive technique in root canal filling. This quantitative systematic evaluation study recognizes that ultrasound-activated root canal sealers have demonstrated significant potential to achieve complete obturation in single-cone obturation.