Effect of sonic and ultrasonic activation on physicochemical properties of root canal sealers

Abstract Objective: To evaluate the effect of ultrasonic and sonic activation on physicochemical properties of AH Plus, MTA Fillapex, ADSeal, GuttaFlow Bioseal, and GuttaFlow 2 sealers. Methodology: Three experimental groups were formed: no activation (NA), ultrasonic activation (UA), and sonic activation (SA). The sealers were manipulated according to the manufacturers’ instructions. A 3-mL syringe was adapted to receive 1 mL of sealer. Activation was performed with a 20/.01 ultrasonic insert (20 s/1W) in the UA group. A size 35.04 sonic tip was used (20 s/10,000 cycles/min-1) in the SA group. The molds for physicochemical analysis were filled and evaluated according to ANSI/ADA specification no. 57: setting time (ST), flow (FL), dimensional change (DC), solubility (SB), and radiopacity (RD). Statistical analysis was performed by Kruskal-Wallis, one-way ANOVA, and Tukey's tests (P<0.05). Results: Regarding ST, only AH Plus and GuttaFlow 2 in the NA group met the ANSI/ADA standards. All FL values were greater than 20 mm in diameter, as determined by ANSI/ADA. The tested sealers and protocols did not comply with the ANSI/ADA standards for DC. As for SB, only MTA Fillapex, regardless of the activation protocol, did not follow the ANSI/ADA standards. All of the investigated sealers, regardless of the activation protocol, presented radiographic density higher than 3 mm Al, as proposed by ANSI/ADA. Conclusions: UA and SA promoted changes in the physicochemical properties of the evaluated root canal sealers, mainly in ST and F. Thus, it is important to evaluate the physicochemical properties of endodontic sealers associated with activation techniques prior to clinical application in order to determine whether the properties follow the parameters set by ANSI/ADA, ensuring safety and quality of root canal filling.

摘要 研究目的：评估超声激活与声波激活对AH Plus、MTA Fillapex、ADSeal、GuttaFlow Bioseal及GuttaFlow 2五种根管封闭剂理化性质的影响。
研究方法：设置三组实验组：无激活组（no activation, NA）、超声激活组（ultrasonic activation, UA）及声波激活组（sonic activation, SA）。严格按照生产商说明书调配各根管封闭剂。使用3mL注射器装载1mL封闭剂。超声激活组采用20/.01超声工作尖，以20 s/1W参数实施激活；声波激活组采用35.04型声波工作尖，以20 s/10000循环·分钟⁻¹参数实施激活。参照美国国家标准学会/美国牙科协会（American National Standards Institute/American Dental Association, ANSI/ADA）第57号规范，制备用于理化分析的模具，并依次检测凝固时间（setting time, ST）、流动度（flow, FL）、体积变化（dimensional change, DC）、溶解度（solubility, SB）及阻射性（radiopacity, RD）。统计分析采用Kruskal-Wallis检验、单因素方差分析及Tukey检验，检验水准设定为P<0.05。
研究结果：针对凝固时间指标，仅无激活组的AH Plus与GuttaFlow 2符合ANSI/ADA规范要求。所有受试封闭剂的流动度直径均大于20mm，满足ANSI/ADA标准。受试封闭剂及各类激活方案均未达到ANSI/ADA对体积变化的限值要求。关于溶解度指标，仅MTA Fillapex无论采用何种激活方案，均未符合ANSI/ADA规范。所有受试封闭剂无论搭配何种激活方案，其阻射密度均高于ANSI/ADA所规定的3mm铝当量标准。
研究结论：超声激活与声波激活均可改变受试根管封闭剂的理化性质，尤以凝固时间与流动度的变化最为显著。因此，在临床应用前，需对结合激活技术的根管封闭剂理化性质开展评估，以确认其是否符合ANSI/ADA设定的参数标准，从而保障根管充填的安全性与充填质量。