Khurana Pardeep, Nainan Mohan Thomas, Sodhi Kiranmeet Kaur, Padda Bupinder Kaur
Department of Conservative Dentistry and Endodontics, Swami Devi Dyal Dental College and Hospital, Panchkula, India.
J Conserv Dent. 2011 Jul;14(3):264-8. doi: 10.4103/0972-0707.85809.
The purpose of this study was to investigate change of working length in curved molar root canals after preparation with Profile, ProTaper and K3 Rotary Nickel-Titanium (Ni-Ti) instruments.
One hundred and eighty maxillary and mandibular molars were divided into group I having root curvature angle <300 and group II having root curvature angle >300 comprising 90 teeth in each group based on Schneider's method. Group II and I were further divided into sub group A, B and C having 30 teeth each based on type of instrument used. Profiles, ProTaper and K3 Rotary Ni-Ti files were used to prepare mesial and buccal roots of molars. Radiography platform was made to allow technique for constant object to film distance and object to sensor distance. Conventional access opening was prepared in each tooth. Preoperative and postoperative working length was measured to an accuracy of 0.1 of mm on Dexis 3.0 direct digital radiograph's onscreen measurement device.
Mean loss of working length varied from 0.28 to 0.92 mm. Highest working length loss was seen in ProTaper followed by K3 files and Profiles, which is statistically significant.
本研究旨在探讨使用Profile、ProTaper和K3旋转镍钛（Ni-Ti）器械预备弯曲磨牙根管后工作长度的变化。
根据施奈德方法，将180颗上颌和下颌磨牙分为两组，I组牙根弯曲角度<30°，II组牙根弯曲角度>30°，每组90颗牙。根据所使用器械的类型，II组和I组又进一步分为A、B、C三个亚组，每组30颗牙。使用Profile、ProTaper和K3旋转Ni-Ti锉预备磨牙的近中根和颊根。制作放射摄影平台，以确保物体到胶片的距离和物体到传感器的距离恒定。对每颗牙齿进行常规开髓。在Dexis 3.0直接数字化X线片的屏幕测量装置上测量术前和术后的工作长度，精确到0.1毫米。
工作长度的平均缩短量在0.28至0.92毫米之间。ProTaper组工作长度缩短最多，其次是K3锉组和Profile组，差异具有统计学意义。
