Vallittu P K
Scandinavian Institute of Dental Materials, Haslum, Norway.
J Prosthet Dent. 1998 Feb;79(2):125-30. doi: 10.1016/s0022-3913(98)70204-5.
This study determined the load required to fracture a three-unit provisional fixed partial denture restoration, which had been reinforced with an experimental glass fiber reinforcement.
Provisional fixed partial dentures (n = 5) were fabricated from a resin of polyethyl methacrylate powder and n-butylmethacrylate liquid. The fixed partial dentures in the control group were unreinforced. In the other groups, the fixed partial dentures were reinforced either with one, two, or three unidirectional glass fiber reinforcements and one glass fiber weave reinforcement. The load was applied to the fixed partial dentures by a steel ball placed in the cavity in the middle fossa of the pontic tooth. A longitudinal section of the fixed partial denture was made to determine the position of the reinforcements. Means were compared by analysis of variance.
The load required to fracture the unreinforced fixed partial denture was 614 N, while incorporation of one unidirectional reinforcement increased the load to 660 N, two reinforcements to 818 N, three reinforcements to 827 N, and three reinforcements with one weave reinforcement to 973 N. It was found that the unidirectional reinforcements were positioned on the side of the occlusal surface of the fixed partial denture, namely, the side of compression during loading.
The results suggest that, even though the glass fiber reinforcements were positioned on the least favorable side of the fixed partial denture in terms of the physical properties of the materials, these reinforcements considerably increased the fracture resistance of the provisional fixed partial denture.
本研究确定了用一种实验性玻璃纤维增强材料加固的三单位临时固定局部义齿修复体发生断裂所需的载荷。
用聚甲基丙烯酸乙酯粉末和甲基丙烯酸正丁酯液体的树脂制作临时固定局部义齿（n = 5）。对照组的固定局部义齿未进行增强。在其他组中，固定局部义齿分别用一层、两层或三层单向玻璃纤维增强材料以及一层玻璃纤维编织增强材料进行增强。通过放置在桥体牙中央窝窝洞内的钢球对固定局部义齿施加载荷。制作固定局部义齿的纵剖面以确定增强材料的位置。采用方差分析比较均值。
未增强的固定局部义齿发生断裂所需的载荷为614 N，而加入一层单向增强材料使载荷增加到660 N，两层增强材料时为818 N，三层增强材料时为827 N，三层增强材料加一层编织增强材料时为973 N。发现单向增强材料位于固定局部义齿咬合面一侧，即加载时的受压侧。
结果表明，尽管从材料物理性能角度来看玻璃纤维增强材料位于固定局部义齿最不利的一侧，但这些增强材料显著提高了临时固定局部义齿的抗断裂能力。
