Goldschmidt Stephanie, Collins Caitlyn J, Hetzel Scott, Ploeg Heidi-Lynn, Soukup Jason W
1 Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA.
2 Bone and Joint Biomechanics Lab, Department of Mechanical Engineering, College of Engineering, University of Wisconsin-Madison, Madison, WI, USA.
J Vet Dent. 2016 Sep;33(3):146-150. doi: 10.1177/0898756416676558.
The reported failure rate for full veneer crowns of canine teeth of dogs is suboptimal, particularly in teeth with naturally poor retentive features, such as those with low height/diameter (H/D) ratios or high convergence angles (CAs). The objective of the present study was to evaluate the application of axial grooves in an effort to develop a crown preparation design that enhances the retention of full veneer crowns in dogs. Crown dislodgment testing was performed on cast alloy dies of canine teeth with unfavorable retention features (low H/D and high CA) prepared with (n = 14) and without axial grooves (n = 15) to evaluate the force required to dislodge a cemented full veneer crown. The crown/die units were secured within a universal testing machine and a load was applied at the 45° oblique direction from distal to mesial to replicate the vector encountered during biting-pulling action. The maximum force required to cause crown dislodgment was recorded for each crown. Statistical analysis revealed a significant increase in force required for crown dislodgment when axial grooves were included in the crown preparation design ( P < .001). Crown retention is improved in canine teeth with otherwise poor retention features when axial grooves are made in the labial and palatal/lingual walls during crown preparation.
据报道，犬类犬齿全冠修复的失败率并不理想，尤其是在那些固位特征天生较差的牙齿上，比如那些高度/直径（H/D）比值较低或聚合角（CA）较高的牙齿。本研究的目的是评估轴向沟的应用，以开发一种能增强犬类全冠修复固位力的牙冠预备设计。对具有不利固位特征（低H/D和高CA）的犬齿铸造合金代型进行牙冠脱位测试，其中一部分（n = 14）制备了轴向沟，另一部分（n = 15）未制备轴向沟，以评估使粘结的全冠修复体脱位所需的力。将牙冠/代型单元固定在万能试验机内，并从远中向近中以45°斜向施加负荷，以模拟咬-拉动作中遇到的力向量。记录每个牙冠脱位所需的最大力。统计分析显示，当牙冠预备设计中包含轴向沟时，牙冠脱位所需的力显著增加（P < .001）。在牙冠预备过程中，当在唇侧和腭侧/舌侧壁制作轴向沟时，具有其他较差固位特征的犬齿的牙冠固位力得到改善。
