Improvement in its durability and surface deterioration of dental restorative materials due to surface-contact fatigue

本文研究了两种PMMA(AC和SU)、两种复合树脂(ES和SD)、三种义齿(LP、SP和AT)和三种贵金属合金(T-1、T-4和12GS)在37℃蒸馏水中的表面接触疲劳。将直径15 mm，厚2.0 mm的圆盘标本放入聚甲基丙烯酸甲酯平板的空腔中，用防水砂纸研磨抛光，然后加入1.0μm氧化铝，在37℃的蒸馏水中保存24小时。试验是在200gf下通过直径2 mm的红宝石球进行的，该球以500rpm的速度旋转，使用滚球装置。以规则的间隔直接在试件上测定表面轮廓。疲劳寿命被定义为产生5μm深的轨道的循环次数，并通过插值法确定。AC、ES、SD和SU的疲劳寿命为5.88×103~8.82×104次。不含无机填料的AC和SU比含更多无机填料的ES具有更好的抗接触疲劳性能。三种人工牙(LP、SP和AT)的疲劳寿命在3.1×104~5.88×104次之间，LP的接触疲劳抗力低于SP和AT。此外，三种贵金属合金的循环次数在10~104次之间，其二维轮廓具有不同于两种复合树脂和义齿的延性特征。

The purpose of this paper was to investigate the surface contact fatigue of two PMMAs (AC and SU), tow composite resins (ES and SD), three artificial tooth (LP, SP and AT) and three noble metal alloys (T-1, T-4 and 12GS) in an atmosphere of dripped distilled-water at 37℃. Disk specimen 15mm diameter by 2.0mm thick were set into cavity cut in plate of PMMA, and were ground and polished down using water-proof sandpaper followed by 1.0μm alumina and then stored for 24h in distilled water at 37℃. Test was carried out under 200 gf through a ruby ball 2mm diameter, which was rotated at 500rpm, using a rolling-ball device. A surface profile was determined directly on the test specimen at regular intervals. Fatigue life was defined as the number of cycles to produce a track 5μm deep and was determined by interpolation. The fatigue life of AC, ES, SD and SU was ranged from 5.88×10^3～8.82×10^4 cycles. AC and SU without inorganic filler are very much more resistant to contact fatigue than ES containing inorganic filler more. On the other hand, the fatigue life of three artificial tooth (LP, SP and AT) was ranged from 3.1×10^4～5.88×10^4 cycles and LP is lower resistant to contact fatigue than SP and AT. Furthermore three noble metal alloys was ranged from 10^3～10^4 cycles and the two-dimensional profile had a ductility characteristic that is different from two composite resin and artificial tooth.