Acharya Nisha, Hasan Md Riasat, Kafle Dashrath, Chakradhar Anil, Saito Takashi
Department of Conservative Dentistry and Endodontics, Kathmandu University School of Medical Sciences, Dhulikhel Hospital, Dhulikhel 45200, Nepal.
Division of Clinical Cariology and Endodontology, Department of Oral Rehabilitation, School of Dentistry, Health Sciences University of Hokkaido, Hokkaido 061-0293, Japan.
Dent J (Basel). 2020 Apr 29;8(2):38. doi: 10.3390/dj8020038.
Endodontic treatment should be both conservative and effective. Endodontic instruments with a greater taper are used for coronal flaring, for proper debridement with efficient irrigation. However, increased taper of an instrument can remove a larger amount of pericervical dentin, compromising the strength of the tooth. The aim of this study was to determine the effect of hand files, ProTaper Universal, ProTaper Next, and V Taper rotary instrument systems on the fracture resistance of teeth. In total, 60 extracted human maxillary first premolars were divided into four groups-Group I (Hand Files; HF), Group II (ProTaper Universal; PT), group III (ProTaper Next; PTN) and Group IV (V Taper; VT) (N = 15). Each group was instrumented with the respective instrument system, irrigated, obturated, restored, and mounted in cold cure acrylic. A universal load-testing machine (Shimadzu, Japan) was used to apply a vertical compressive load. The maximum force was recorded in Newton. Analysis of variance (ANOVA) and Independent -tests were applied to compare the maximum mean force required to fracture the tooth. There was a statistically significant difference in fracture resistance between Group I (HF) and Group II (PT) and between Group II (PT) and Group IV (VT) ( < 0.001). Similarly, a significant difference was observed between Group II (PT) and Group III (PTN) ( < 0.01). Furthermore, a significant difference was observed between Group I (HF) and Group III (PTN), and between Group III (PTN) and Group IV (VT) ( < 0.05), too. However, there was no statistically significant difference between Group I (HF) and group IV (VT) ( > 0.05). Rotary files with more taper seem to remove more pericervical dentin than traditional manual and rotary files with less taper, thus altering the strength of the tooth.
牙髓治疗应兼具保守性和有效性。锥度更大的牙髓器械用于冠部扩通，以便通过有效的冲洗进行适当的清创。然而，器械锥度增加会去除更多的颈周牙本质，从而损害牙齿的强度。本研究的目的是确定手动锉、ProTaper Universal、ProTaper Next和V Taper旋转器械系统对牙齿抗折性的影响。总共60颗拔除的人类上颌第一前磨牙被分为四组——第一组（手动锉；HF）、第二组（ProTaper Universal；PT）、第三组（ProTaper Next；PTN）和第四组（V Taper；VT）（N = 15）。每组使用相应的器械系统进行预备、冲洗、充填、修复，并固定在冷固化丙烯酸树脂中。使用万能材料试验机（日本岛津）施加垂直压缩载荷。以牛顿为单位记录最大力。采用方差分析（ANOVA）和独立样本t检验来比较牙齿折断所需的最大平均力。第一组（HF）和第二组（PT）之间以及第二组（PT）和第四组（VT）之间的抗折性存在统计学显著差异（P < 0.001）。同样，在第二组（PT）和第三组（PTN）之间观察到显著差异（P < 0.01）。此外，在第一组（HF）和第三组（PTN）之间以及第三组（PTN）和第四组（VT）之间也观察到显著差异（P < 0.05）。然而，第一组（HF）和第四组（VT）之间没有统计学显著差异（P > 0.05）。与传统的锥度较小的手动和旋转锉相比，锥度更大的旋转锉似乎会去除更多的颈周牙本质，从而改变牙齿的强度。
