Department of Restorative Sciences, Faculty of Dentistry, Kuwait University, Alsafat, Kuwait.
Int Endod J. 2011 Oct;44(10):956-66. doi: 10.1111/j.1365-2591.2011.01917.x. Epub 2011 Jul 14.
To investigate the effect of root canal and post-space preparation on the remaining dentine thickness in the apical region of maxillary central and lateral incisors.
Fifty extracted maxillary incisors (25 centrals and 25 laterals) were mounted and then sectioned at two levels: 5 and 7 mm from the apex. Computerized images were obtained and a digital image analysis system was used to measure dentine thickness for each section at eight sites: labial, mesial, distal, palatal, mesio-labial, disto-labial, mesio-palatal and disto-palatal. Measurements were repeated at baseline and after both root canal and post-space preparation. Central and lateral incisors were divided into five groups each (n = 5) according to the drill used for post-space preparation: Groups 1 through 4 were prepared using Parapost drills sizes 4.5, 5, 5.5 and 6 respectively. For group 5, size 4 Gates Glidden was used.
For both teeth, and at the two levels there was a significant difference (P < 0.001) between the baseline dentine thickness and that remaining after post-space preparation at all sites. There was a statistically significant difference (P = 0.007) between the remaining dentine thickness at 5 and 7 mm at all sites. The average amount of dentine removed ranged from 0.20 to 0.52 mm. In all groups, and for both teeth, some specimens had <1 mm of remaining dentine thickness.
Posts should be used carefully when restoring root filled maxillary incisors.
研究根管和桩腔预备对上颌中切牙和侧切牙根尖区剩余牙本质厚度的影响。
将 50 颗上颌切牙（25 颗中切牙和 25 颗侧切牙）进行牙体固定并分别在距根尖 5mm 和 7mm 处进行横断，获得计算机图像后使用数字图像分析系统在八个部位（唇侧、近中、远中、腭侧、近中唇侧、远中唇侧、近中腭侧和远中腭侧）对每个截面的牙本质厚度进行测量。在基线以及根管和桩腔预备后分别重复测量。根据桩腔预备时使用的扩孔钻，将中切牙和侧切牙分为五组（每组 5 个）：第 1 组至第 4 组分别使用 4.5、5、5.5 和 6 号 Parapost 扩孔钻，第 5 组使用 4 号 Gates Glidden 扩孔钻。
对于两种牙齿，在两个水平上，所有部位的基线牙本质厚度与桩腔预备后剩余的牙本质厚度之间存在显著差异（P<0.001）。所有部位的 5mm 和 7mm 处剩余牙本质厚度之间存在统计学显著差异（P=0.007）。牙本质去除量的平均值范围为 0.20 至 0.52mm。在所有组中，对于两种牙齿，一些标本的剩余牙本质厚度<1mm。
在上颌前牙根管治疗后修复时应谨慎使用桩。
