Veiga de Almeida University, Rio de Janeiro, Brazil.
J Endod. 2011 May;37(5):701-5. doi: 10.1016/j.joen.2011.02.001. Epub 2011 Mar 23.
Oval-shaped canals represent a challenge for rotary nickel-titanium (NiTi) files because buccal and/or lingual recesses are commonly left uninstrumented. The aim of the present study was to evaluate the debridement quality of the Self-Adjusting File (SAF) system in oval canals and compare it with the debridement achieved by a commonly used NiTi rotary system.
A careful specimen selection resulted in two equal groups each consisting of 12 extracted mandibular canines with oval canals that had vital pulps before extraction. All canals had a buccolingual diameter that was at least 2.5 times larger than that of the mesiodistal one as defined from radiographs. One group was subjected to the SAF protocol, whereas the other group underwent conventional protocol; the ProTaper system up to the F2 instrument was used with syringe and open end needle irrigation. Sodium hypochlorite (5.25%) was used as an irrigant for both groups. The roots were then histologically processed and 0.6-μm-thick cross-sections were obtained every 0.5 mm from the 1- to 5-mm apical levels. Morphometric evaluation was performed on cross-sections to determine the amount of remaining pulp tissue as a percent of the root canal area.
The group-by-location interaction was not significant (P > .05), which means that the group comparisons were not dependent on the cross-sectional level. There was significantly greater residual pulp tissue left after ProTaper system instrumentation versus SAF instrumentation (21.4% vs 9.3%, P < .05).
The SAF protocol was significantly more efficient for debridement of oval root canals than the rotary ProTaper protocol.
椭圆形根管对旋转镍钛（NiTi）锉来说是一个挑战，因为颊舌向或近远中向的凹陷通常未被清理。本研究的目的是评估自调整锉（SAF）系统在椭圆形根管中的清创质量，并与常用的 NiTi 旋转系统的清创效果进行比较。
仔细选择标本后，每组各有 12 颗具有活力牙髓的下颌前磨牙，在提取前具有椭圆形根管。所有根管的颊舌向直径至少是近远中向直径的 2.5 倍，这是从射线照片上定义的。一组采用 SAF 方案，另一组采用常规方案；ProTaper 系统用到 F2 锉，使用注射器和敞开端的冲洗针进行冲洗。两组均使用次氯酸钠（5.25%）作为冲洗液。然后对牙根进行组织学处理，从 1 到 5mm 的根尖水平每隔 0.5mm 获得 0.6μm 厚的横截面。在横截面上进行形态计量评估，以确定剩余牙髓组织占根管面积的百分比。
组-位置交互作用不显著（P＞0.05），这意味着组间比较不受横截面水平的影响。与 SAF 器械相比，ProTaper 系统器械清理后剩余的牙髓组织明显更多（21.4%比 9.3%，P＜0.05）。
与 ProTaper 旋转锉系统相比，SAF 方案在清理椭圆形根管方面效率更高。
