Tyler M W, Fitzgerald M, Dennison J B, Heys D R
University of Michigan School of Dentistry, Department of Cariology and General Dentistry, Ann Arbor 48109, USA.
Oper Dent. 1994 May-Jun;19(3):116-20.
Previous studies of the bonding capabilities of glass-ionomer cements have concentrated on the use of in vitro testing conditions. Since early moisture contamination appears to have adverse effects on the physical properties of glass-ionomer cements, and with the probability of pulpally derived dentinal fluid being present under in vivo conditions, the objective of this study was to compare in vivo tensile bond strength with in vitro tensile bond strength of a glass-ionomer cement to dentin utilizing the same teeth under similar test conditions. A glass-ionomer lining cement was placed on freshly exposed labial dentin of the maxillary incisor on 10 Rhesus monkeys. Immediately following placement, an orthodontic button was placed over the cement and left undisturbed for 1 hour. The teeth were then extracted and stored in 100% relative humidity for 23 hours. An Instron testing machine was used to register in kilograms the force required to cause tensile bond failure of the cement. Identical methodology was then used on the same teeth for in vitro testing. The concluding results indicate that a statistically significant difference (P < or = 0.05) exists between in vivo and in vitro tensile bond strengths of the glass-ionomer lining cement and that the bond failure was cohesive in character for all cases both in vivo and in vitro. These findings suggest that clinically, tensile bond strengths of glass-ionomer cements to cut dentin can be expected to be weaker in vital teeth than in devital teeth.
以往关于玻璃离子水门汀粘结能力的研究主要集中在体外测试条件的应用上。由于早期的水分污染似乎会对玻璃离子水门汀的物理性能产生不利影响，并且在体内条件下存在牙髓来源的牙本质液的可能性，本研究的目的是在相似的测试条件下，利用相同的牙齿比较玻璃离子水门汀与牙本质的体内拉伸粘结强度和体外拉伸粘结强度。将一种玻璃离子衬层水门汀置于10只恒河猴上颌切牙新暴露的唇面牙本质上。放置后立即在水门汀上放置一个正畸纽扣，并静置1小时。然后将牙齿拔出并在100%相对湿度下保存23小时。使用Instron测试机以千克为单位记录导致水门汀拉伸粘结失败所需的力。然后对相同的牙齿采用相同的方法进行体外测试。最终结果表明，玻璃离子衬层水门汀的体内和体外拉伸粘结强度之间存在统计学上的显著差异（P≤0.05），并且在体内和体外的所有情况下粘结失败均为内聚性。这些发现表明，在临床上，活髓牙中玻璃离子水门汀与切割牙本质的拉伸粘结强度可能比死髓牙中的弱。
