임플란트에 대한 지르코니아 지대주의 적합도

Abstract

Since the concept of osseointegration was introduced in the field of dentistry, the implant has been used for the restoration of missing teeth. Because of the increased esthetic demands of the patients, however, the needs of esthetic abutment have been raised. Zirconia has excellent esthetics as well as good mechanical properties, so this material can be used as the abutment for the implant fixture where the esthetics is emphasized. But mechanical cutting method has to be used for making the zirconia abutment, so CAD/CAM (Computer-Assisted Design/Computer-Assisted Manufacturing) system was introduced. However, it costs too much to set up the CAD/CAM system. And the precision of the milling machine itself and skillful operators who can handle the machine well were needed. With the current CAD/CAM system, however, the precise representation of the internal- hex connection type abutment is virtually impossible. Therefore, to make up this disadvantage, MAD/MAM (Manually-Assisted Design/Manually-Assisted Manufacturing) system which includes a manual process is introduced. In this study, 10 titanium prefabricated abutments and 10 zirconia customized abutments were made as a control group and experimental group respectively and the marginal gaps were measured. The results were as follows. In control group, the average of the marginal gaps was less than 10㎛ which is the limit measurement of the optical microscope used for this study. And In case of experimental group, the averages of the marginal gaps were 110.5 ± 58.75 ㎛ in the internal-hex connection type and 54.2 ± 61.60 ㎛ in the external-hex connection type each. Because the internal-hex connection type abutment had larger marginal gap than the external-hex connection type abutment, it is more difficult to make customized abutment of the internal-hex connection type than that of the external-hex connection type. And the large standard deviation of the data shows that the status of the abutment can be different by the proficiency of the operator in MAD/MAM system. In conclusion, to produce the precise and homogeneous restoration stably in the MAD/MAM system which can make the zirconia prothesis without much installation costs, the use of sharp milling machine, improvement of the precision of the machine and improvement of proficiency of the operator will be required.