Khan S B, Geerts G
Department of Restorative Dentistry, University of the Western Cape, Tygerberg.
Eur J Prosthodont Restor Dent. 2009 Jun;17(2):67-72.
Light-cured acrylic resin custom tray material is used in commercial dental laboratories but little evidence-based scientific information on its physical properties is available.
This study investigates the dimensional stability of light-cured acrylic resin custom tray material and compares its fracture toughness and flexural strength to a chemically-cured acrylic material.
For dimensional stability, 20 light-cured specimens were fabricated and measured 3 times at regular time intervals over 48 hours. Mean shrinkage was calculated for each time interval and the mean values were compared to the standard using the Wilcoxon Rank Sum test. A p-value of <0.05 was considered significant. For fracture toughness, 2 groups of 20 light-cured and chemically-cured acrylic materials with a single-edge notch were subjected to a compressive load using the 3-point bending technique. For flexural strength, 1 group (n=20) of each material was subjected to a compressive load using 3-point bending. The highest load before failure was used to calculate the fracture toughness and flexural strength. Differences in fracture toughness and flexural strength values between the 2 groups were compared using ANOVA testing. A p-value of <0.05 was considered significant. The chemically-cured group was accepted as the control group.
Compared to the standard, shrinkage was significant for all time intervals (p<0.05). The difference in shrinkage among time intervals was not significant (p>0.05). The fracture toughness and flexural strength were significantly higher for the light-cured material.
Trays made from light-cured acrylic resin can be used immediately following polymerization. The light-cured material is more resistant to bending and crack propagation than the chemically-cured type.
光固化丙烯酸树脂定制托盘材料在商业牙科实验室中使用，但关于其物理性能的循证科学信息很少。
本研究调查光固化丙烯酸树脂定制托盘材料的尺寸稳定性，并将其断裂韧性和弯曲强度与化学固化丙烯酸材料进行比较。
对于尺寸稳定性，制作20个光固化样本，并在48小时内定期测量3次。计算每个时间间隔的平均收缩率，并使用Wilcoxon秩和检验将平均值与标准值进行比较。p值<0.05被认为具有显著性。对于断裂韧性，使用三点弯曲技术对两组各20个带有单边切口的光固化和化学固化丙烯酸材料施加压缩载荷。对于弯曲强度，每种材料的一组（n=20）使用三点弯曲施加压缩载荷。失效前的最高载荷用于计算断裂韧性和弯曲强度。使用方差分析测试比较两组之间断裂韧性和弯曲强度值的差异。p值<0.05被认为具有显著性。化学固化组被视为对照组。
与标准值相比，所有时间间隔的收缩率均具有显著性（p<0.05）。时间间隔之间的收缩率差异不显著（p>0.05）。光固化材料的断裂韧性和弯曲强度显著更高。
由光固化丙烯酸树脂制成的托盘在聚合后可立即使用。光固化材料比化学固化类型更耐弯曲和抗裂纹扩展。
