Department of Endodontology, The Goldschleger School of Dental Medicine, Tel Aviv University, Tel Aviv, Israel.
J Endod. 2010 Apr;36(4):679-90. doi: 10.1016/j.joen.2009.12.036.
To introduce a new concept, the self-adjusting file (SAF), and discuss its unique features compared with current rotary nickel-titanium file systems.
The SAF file is hollow and designed as a thin cylindrical nickel-titanium lattice that adapts to the cross-section of the root canal. A single file is used throughout the procedure. It is inserted into a path initially prepared by a # 20 K-file and operated with a transline- (in-and-out) vibration. The resulting circumferential pressure allows the file's abrasive surface to gradually remove a thin uniform hard-tissue layer from the entire root canal surface, resulting in a canal with a similar cross-section but of larger dimensions. This holds also for canals with an oval or flat cross-section, which will be enlarged to a flat or oval cross-section of larger dimensions. The straightening of curved canals is also reduced because of the high pliability of the file and the absence of a rigid metal core. Thus, the original shape of the root canal is respected both longitudinally and in cross-section. The hollow SAF file is operated with a constant flow of irrigant that enters the full length of the canal and that is activated by the vibration and is replaced continuously throughout the procedure. This results in effective cleaning even at the cul de sac apical part of the canal. The SAF has high mechanical endurance; file separation does not occur; and mechanical failure, if it occurs, is limited to small tears in the latticework.
The SAF represents a new step forward in endodontic file development that may overcome many of the shortcomings of current rotary nickel-titanium file systems.
介绍一种新概念，即自调整锉（SAF），并讨论其与当前旋转镍钛锉系统相比的独特特点。
SAF 锉是空心的，设计为薄的圆柱形镍钛晶格，适应根管的横截面。整个过程中使用单个锉。它插入到最初由 #20 K 锉制备的路径中，并以直线内-（进出）振动操作。产生的圆周压力允许锉的研磨表面逐渐从整个根管表面去除一层薄的均匀硬组织层，从而形成具有相似横截面但尺寸更大的根管。对于椭圆形或扁平横截面的根管也是如此，它们将被扩大到尺寸更大的扁平或椭圆形横截面。由于锉的高柔韧性和没有刚性金属芯，弯曲根管的拉直也减少了。因此，根管的原始形状在纵向和横截面上都得到了尊重。空心 SAF 锉在持续的冲洗剂流中操作，冲洗剂进入根管的全长，并通过振动激活，并在整个过程中不断更换。这可确保即使在根管的根尖部也能有效清洁。SAF 具有高机械耐力；不会发生锉分离；并且如果发生机械故障，也仅限于晶格的小撕裂。
SAF 代表了根管锉发展的新一步，它可能克服当前旋转镍钛锉系统的许多缺点。
