Arias Ana, Lee Yoon H, Peters Christine I, Gluskin Alan H, Peters Ove A
Department of Endodontics, University of the Pacific, Arthur A. Dugoni School of Dentistry, San Francisco, California.
Department of Endodontics, University of the Pacific, Arthur A. Dugoni School of Dentistry, San Francisco, California.
J Endod. 2014 Jul;40(7):982-5. doi: 10.1016/j.joen.2013.12.003. Epub 2014 Jan 8.
The purpose of this pilot study in a cadaver model was to compare 2 different shaping techniques regarding the induction of dentinal microcracks.
Three lower incisors from each of 6 adult human cadaver skulls were randomly distributed into 3 groups: the control group (CG, no instrumentation), the GT group (GT Profile hand files; Dentsply Tulsa Dental, Tulsa, OK), and the WO group (WaveOne; Dentsply Tulsa Dental). In the GT group, manual shaping in a crown-down sequence with GT Profile hand files was performed. In the WO group, Primary WaveOne files were used to the working length. Teeth were separated from the mandibles by careful removal of soft tissue and bone under magnification. Roots were sectioned horizontally at 3, 6, and 9 mm from the apex using a low-speed saw. Color photographs at 2 magnifications (25× and 40×) were obtained. Three blinded examiners registered the presence of microcracks (yes/no), extension (incomplete/complete), direction (buccolingual/mesiodistal), and location. Data were analyzed with chi-square tests at P < .05.
Microcracks were found in 50% (CG and GT) and 66% (WO) of teeth at 3 mm, 16.6% (CG) and 33.3% (GT and WO) at 6 mm, and 16.6% in all 3 groups at 9 mm from the apex. There were no significant differences in the incidence of microcracks between all groups at 3 (P = .8), 6 (P = .8), or 9 mm (P = 1). All microcracks were incomplete, started at the pulpal wall, and had a buccolingual direction.
Within the limitations of this pilot study, a relationship between the shaping techniques (GT hand and WaveOne) and the incidence of microcracks could not be shown compared with uninstrumented controls.
本尸体模型的初步研究目的是比较两种不同的预备技术对牙本质微裂纹形成的影响。
从6具成人尸体颅骨上各取下3颗下颌切牙，随机分为3组：对照组（CG，未进行器械预备）、GT组（GT Profile手动锉；登士柏 Tulsa Dental，塔尔萨，俄克拉何马州）和WO组（WaveOne；登士柏 Tulsa Dental）。GT组使用GT Profile手动锉按冠向根向顺序进行手动预备。WO组使用WaveOne初尖锉预备至工作长度。在放大镜下小心去除软组织和骨组织，将牙齿从下颌骨分离。使用低速锯在距根尖3、6和9 mm处水平切断牙根。获取2种放大倍数（25倍和40倍）的彩色照片。3名不知情的检查者记录微裂纹的存在（有/无）、扩展情况（不完全/完全）、方向（颊舌向/近远中向）和位置。采用卡方检验分析数据，P < 0.05。
在距根尖3 mm处，50%（CG组和GT组）和66%（WO组）的牙齿出现微裂纹；在6 mm处，16.6%（CG组）和33.3%（GT组和WO组）的牙齿出现微裂纹；在距根尖9 mm处，3组中均有16.6%的牙齿出现微裂纹。在3 mm（P = 0.8）、6 mm（P = 0.8）或9 mm（P = 1）处，各组间微裂纹发生率无显著差异。所有微裂纹均为不完全裂纹，起始于髓壁，方向为颊舌向。
在本初步研究的局限性范围内，与未进行器械预备的对照组相比，未发现预备技术（GT手动锉和WaveOne）与微裂纹发生率之间存在关联。
