Tilakchand Mahima, Jain Abhishek, Naik Balaram
Department of Conservative Dentistry and Endodontics, S.D.M. College of Dental Sciences and Hospital, Sattur, Dharwad, Karnataka, India.
J Conserv Dent. 2016 Jul-Aug;19(4):317-22. doi: 10.4103/0972-0707.186450.
The purpose of this study was to evaluate the three-dimensional expansion of Gutta-percha (GP), at various powder/liquid ratios, of a zinc oxide-eugenol (ZOE)-based sealer using spiral computed tomography (SCT).
Thirty-five freshly extracted human mandibular premolars were selected for this study. Cleaning and shaping were performed in all the teeth initially with hand K-files up to #25 and finally with RaCe rotary instruments (25/06). Teeth were randomly divided into five groups of 7 teeth each. Specimens were scanned using SCT. They were then viewed both cross-sectionally and longitudinally, with a constant thickness of 1 mm/slice. The volume of root canal in each tooth was estimated. Obturation was performed by GP points (25/04) and ZOE-based root canal sealer in all groups with different powder-liquid ratio. Groups 1, 2, 3, and 4, had powder/liquid ratio of 1:1, 1:2, 1:3, and 1:4, respectively, while in the control group, no sealer was used. The obturation was performed by sealer coated single cone GP. A second SCT scan was performed to determine the volume of GP and sealer in all four groups 1 day after obturation. The third and fourth SCT scans were taken 7 and 30 days after obturation, respectively. The mean volume of GP per group was calculated. Data were statistically analyzed using one-way ANOVA. Inter-group comparisons were done using Scheffe post hoc multiple comparisons test.
All groups with sealer showed expansion of GP at both 7(th) day and 30(th) day, which was statistically significant from the GP volume at 1(st) day. Groups 2 and 3 with powder/liquid ratio of 1:2 and 1:3 gave the highest mean volume values during 30 days period and showed significant expansion in comparison with Groups 1 and 4 with powder/liquid ratio of 1:1 and 1:4, respectively.
Increasing the ratio of eugenol in sealer resulted in the volumetric expansion of GP. However, further studies should be performed to confirm the expansion of GP, leading to the achievement of fluid impervious seal.
本研究旨在使用螺旋计算机断层扫描（SCT）评估氧化锌丁香酚（ZOE）基封闭剂在不同粉液比下牙胶尖（GP）的三维膨胀情况。
本研究选取35颗新鲜拔除的人类下颌前磨牙。所有牙齿最初先用手用K锉清理和预备至#25号，最后用RaCe旋转器械（25/06）进行预备。牙齿随机分为五组，每组7颗。使用SCT对样本进行扫描。然后以每层1mm的恒定厚度进行横断面和纵断面观察。估计每颗牙齿根管的体积。所有组均使用牙胶尖（25/04）和不同粉液比的ZOE基根管封闭剂进行充填。第1、2、3和4组的粉液比分别为1:1、1:2、1:3和1:4，而对照组未使用封闭剂。采用封闭剂涂层单锥牙胶尖进行充填。充填后1天进行第二次SCT扫描，以确定所有四组中牙胶尖和封闭剂的体积。分别在充填后7天和30天进行第三次和第四次SCT扫描。计算每组牙胶尖的平均体积。数据采用单因素方差分析进行统计学分析。组间比较采用Scheffe事后多重比较检验。
所有使用封闭剂的组在第7天和第30天牙胶尖均有膨胀，与第1天牙胶尖体积相比具有统计学意义。粉液比为1:2和1:3的第2组和第3组在30天内平均体积值最高，与粉液比分别为1:1和1:4的第1组和第4组相比，显示出显著膨胀。
封闭剂中丁香酚比例增加会导致牙胶尖体积膨胀。然而，应进行进一步研究以证实牙胶尖的膨胀，从而实现不透液密封。
