Micro-CT를 이용한 맞춤형 CAD/CAM 지대주의 적합에 관한 연구

Abstract

CAD/CAM custom-made abutment has been currently produced in Korea as well. However, doubt has been increasing about the precision and stability between CAD/CAM custom-made abutment, fixture, and screw. In this study, implant fixtures from 2 manufacturers were selected, and ready-made abutment and CAD/CAM custom-made abutment were fabricated. Then, the fitness between fixture, abutment, and screw was studied by reverse torque value and Micro-CT. Implant fixtures were chosen as OSSEOTITE® Certain(Biomet 3i, Palm Beach Garden, FL, USA) and OsseoSpeed™ (Astra, Mölndal, Sweden). 6 ready-made abutments compatible with each fixture and 6 CAD/CAM custom-made abutments(Myplant, Raphabio Co., Seoul, Korea) were fabricated, and screws provided by each company were used. Fixture and abutments were tightened with 20Ncm according to the manufacturer's instruction. Micro-CT was taken for the fitness test, and 3 surfaces were aquired along the line which connected hex points(vertexs), inner connection area of abutment. On the cross-section, the fitness(adaptive) states of the interfaces beween abutment-screw, fixture-abutment, and fixture-screw were observed, and the contact lengths on each interface were measured. Mann-Whitney test (P <.05) was used for statistical analysis of the contact lengths of 2 abutments. Preloding reverse torque values(RTV) were measured 3 times repeatedly for screw stability test. Student t-test (P <.05) was used for significance between RTVs of 2 abutments. The results are as follows: 1. The case of CAD/CAM custom-made abutment shows precise and proper contact on interfaces beween abutment-screw, fixture-abutment, and fixture-screw. Comparing to the case of ready-made abutment, the case of CAD/CAM custom-made abutment has significantly longer contact length on interfaces between abutment-screw, and fixture–screw, but there is no significant difference between fixture-abutment. 2. Comparing to the case of ready-made abutment, the case of CAD/CAM custom-made abutment indicates lower value of the RTV. In conclusion, it is considered that domestically manufactured CAD/CAM custom-made abutment has better fitness and lower initial reverse torque than ready-made abutment.