ABSTRACT
<p><b>OBJECTIVE</b>To investigate evidence supporting whether ultrasonic irrigation as a supplement is more effective than syringe irrigation in root canal cleaning.</p><p><b>METHODS</b>An electronic search was conducted in PubMed, Embase, Web of Science, Cochrane Library, ProQuest Dissertation and Theses, Database for Chinese Technical Periodicals, China National Knowledge Infrastructure, Wanfang Database, and Chinese Biomedical Literature Database. Studies were retrieved from January 1, 1985 to March 1, 2014. The Chinese journals on stomatology and the bibliography of all relevant articles were manually searched. Relevant clinical randomized controlled trial (RCT) and clinical controlled trial (CCT) were selected. Two investigators evaluated the risk of bias of the included trials in accordance with Cochrane risk of bias assessment tools and collected data of included studies. Meta-analysis was then performed in RevMan 5.2.</p><p><b>RESULTS</b>Nine articles that satisfied the eligibility criteria were included in this Meta-analysis. Seven studies showed low bias risk, and the remaining studies exhibited moderate bias risk. Histological results showed that ultrasonic irrigation supplement could significantly improve canal and isthmus debridement at the apical area (P < 0.01). Antibacterial efficacy was evaluated by bacterial culture (P = 0.26) and polymerase chain reaction (P = 0.99) methods, no significant differences in antibacterial efficacy were observed.</p><p><b>CONCLUSION</b>Ultrasonic irrigation supplement is more effective than syringe irrigation in root canal debridement at the apical area. However, antibacterial efficacy is not statistically significant.</p>