CAJ | 학술논문

背景:在临床上,超硬石膏广泛应用于制作固定义齿、大支架可摘义齿等需精细复制口腔情况的工作模型,其抗弯强度足够抵抗脱模时的力量不会发生模型牙体的折断.但当印模为硬质材料如聚醚橡胶印模等,存在牙体折断现象.目的:比较4种超硬石膏YCG,丹特纳,贺利氏,穗诚模型的尺寸精度及抗弯强度.方法:制作三单位固定桥和长方体(50 mm× 10 mm×5 mm)的金属模具,灌注4种超硬石膏模型,分别采用万能工具显微镜和万能试验机测量其尺寸精度及抗弯强度.结果与结论:YCG、丹特纳、贺利氏、穗诚4种超硬石膏近远中方向尺寸精度均值分别为:15.043,15.034,15.037,15.040 mm,颊舌方向为:7.020,7.015,7.019,7.019 mm,牙体长轴方向为:8.022,8.018,8.019,8.02 mm.4种超硬石膏模型抗弯强度均值分别为:15.687,13.000,22.521,18.675 MPa.4种石膏模型尺寸精度差异无显著性意义 (P > 0.05),但抗弯强度差异有高度显著性意义(P < 0.01).贺利氏石膏抗弯强度显著高于其他3种石膏 (P < 0.01),穗诚石膏抗弯强度显著高于丹特纳(P < 0.01).说明贺利氏石膏的抗弯强度是4种超硬石膏中最高者,穗诚的抗弯强度高于丹特纳,提示临床上应根据实际情况尽量选择抗弯强度大的石膏材料.
배경:재림상상,초경석고엄범응용우제작고정의치、대지가가적의치등수정세복제구강정황적공작모형,기항만강도족구저항탈모시적역량불회발생모형아체적절단.단당인모위경질재료여취미상효인모등,존재아체절단현상.목적:비교4충초경석고YCG,단특납,하리씨,수성모형적척촌정도급항만강도.방법:제작삼단위고정교화장방체(50 mm× 10 mm×5 mm)적금속모구,관주4충초경석고모형,분별채용만능공구현미경화만능시험궤측량기척촌정도급항만강도.결과여결론:YCG、단특납、하리씨、수성4충초경석고근원중방향척촌정도균치분별위:15.043,15.034,15.037,15.040 mm,협설방향위:7.020,7.015,7.019,7.019 mm,아체장축방향위:8.022,8.018,8.019,8.02 mm.4충초경석고모형항만강도균치분별위:15.687,13.000,22.521,18.675 MPa.4충석고모형척촌정도차이무현저성의의 (P > 0.05),단항만강도차이유고도현저성의의(P < 0.01).하리씨석고항만강도현저고우기타3충석고 (P < 0.01),수성석고항만강도현저고우단특납(P < 0.01).설명하리씨석고적항만강도시4충초경석고중최고자,수성적항만강도고우단특납,제시림상상응근거실제정황진량선택항만강도대적석고재료.
BACKGROUND: In the clinic, super-hard plaster is widely used for preparation of casts that can duplicate oral cavity situation, such as fixed denture and removable denture. The bending resistance of super-hard plaster can sufficiently resist the force to strip, which would avoid the fracture of tooth model. However, the symptom of tooth model fracture exists when hard material, such as polyether rubber, is used as impression material. OBJECTIVE: To compare the dimensional accuracy and bending resistance among four kinds of super-hard plaster: YCG, Dentona, Heraeus, and Huicheng. METHODS: Mental casts including three unit fixed bridge and cuboid (50 mm×10 mm×5 mm) were prepared and then poured with the above-mentioned four kinds of super-hard plaster. Then dimensional accuracy and bending resistance of the casts were measured through the use of universal tool microscope and universal testing machine. CONCLUSION AND RESULTS: The proximal-distal dimensional accuracy of YCG, Dentona, Heraeus, and Huicheng super-hard plaster casts was 15.043, 15.034, 15.037 and 15.040 mm, respectively, the buccolingual dimensional accuracy was 7.020, 7.015, 7.019, and 7.019 mm, respectively, the tooth long-axis dimensional accuracy was 8.022, 8.018, 8.019, and 8.02 mm, respectively. The bending resistance of the four super-hard plaster casts was 15.687, 13.000, 22.521, 18.675 MPa, respectively. There was no significant difference in dimensional accuracy (P > 0.05), but there was significant difference in bending resistance (P < 0.01), among these four super-hard plaster casts. The bending resistance of Heraeus super-hard plaster cast was significantly greater compared with the other 3 super-hard plaster casts (P < 0.01), and the bending resistance of Huicheng super-hard plaster cast was significantly greater than that of Dentona super-hard plaster cast (P < 0.01). These findings demonstrate that Heraeus super-hard plaster has the highest bending resistance, followed by Huicheng and YCG super-hard plaster casts, and lastly Dentona super-hard plaster cast. These findings suggest that super-hard plaster cast with greater bending resistance should be chosen as possible according to practical situation.