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

本文研究了两种聚甲基丙烯酸甲酯（AC和SU）、两种复合树脂（ES和SD）、三种人工牙（LP、SP和AT）和三种贵金属合金（T-1、T-4和12 GS）在37℃滴蒸馏水气氛中的表面接触疲劳。将直径为15 mm、厚度为2.0mm的圆盘样品放入PMMA板上切割的空腔中，并使用防水砂纸随后使用1.0μm氧化铝研磨和抛光，然后在37℃的蒸馏水中储存24小时。测试在200 gf下通过直径为2 mm的红宝石球进行，该红宝石球使用滚球装置以500 rpm旋转。以规则的间隔直接在试样上测定表面轮廓。疲劳寿命定义为产生5μm深轨迹的循环次数，并通过插值法确定。AC、ES、SD和SU的疲劳寿命在5.88×10^3~8.82×10^4周之间。不含无机填料的AC和SU比含无机填料的ES更耐接触疲劳。LP、SP和AT三种人工牙的疲劳寿命在3.1×10^4~5.88×10^4周之间，LP的接触疲劳抗力低于SP和AT。三种贵金属合金的循环次数在10^3~10^4次之间，其二维轮廓具有不同于两种复合树脂和人工牙的延展性特征。

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.