자가 치아 이식술에 사용되는 Computer-Aided Rapid Prototyping model(CARP model)의 실제 치아에 대한 오차

Abstract

[한글]

카데바를 이용 상하악 block bone를 채득하여 dry 및 wet 상태로 전산화 단층 촬영을 시행하여 V-works 4.0 TM (Cybermed Inc., Seoul, Korea) 소프트웨어를 이용 3차원 영상 모델 재구성 및 CARP 모델을 제작한 후 각각 실제 치아 및 3차원 영상모델과 CARP 모델에서의 치관의 근원심측 및 협설측 최대 풍융부간의 거리와 치경부에서의 근원심측 및 협설측 거리를 측정하여 서로간에 나타난 오차값에 대하여 절대값을 적용, 실제 치아와 3차원 영상모델에 있어 오차 비교 분석을 시행함과 동시에 또한 오차의 분포를 분석하여 각 그룹에 있어 확대 및 축소 경향을 분석하였다.이번 실험을 통해 나타난 실험 결과로는1) 실제 치아와 3차원 영상 모델 사이의 절대값 오차는 평균 0.199 mm, 3차원 영상 모델과 CARP 모델간의 절대값 오차는 평균 0.169 mm, 실제 치아와 CARP 모델 사이의 절대값 오차는 평균 0.291 mm를 보였다.2) 실제 치아와 3차원 영상모델의 절대값의 오차값 비교 분석시 치관과 치경부에 있어서는 유의한 차이가 없었으나 상악과 하악간, wet state와 dry state간에 유의성 있는 차이가 관찰되었다.3) 실제 치아에 대한 3차원 영상 모델과 CARP 모델의 확대 및 축소 경향 분석을 위한 단순 오차의 분포 분석시 실제 치아에 비해 3차원 영상 모델이 축소되는 경향을 나타냈으며, CARP 모델은 3차원 영상 모델에 비해 축소되는 경향을 나타냈다. 또한 CARP 모델 역시 실제 치아에 비해 축소되는 경향을 보였다.4) 상대적인 축소량에 대한 평균값을 산정시 각각 3차원 영상 모델은 실제 치아에 비해 평균 0.149 mm, CARP모델은 3차원 영상 모델에 비해 평균 0.067 mm로 CARP 모델은 실제 치아에 비해 총 0.216 mm의 축소를 나타냈다.이상의 결과로 미루어 볼 때 CARP 모델의 사용은 자가 치아 이식술에서 수용부 골와동의 정밀성을 높이는데 기여하여 수술의 성공 가능성을 높일 수 있을 것으로 생각된다.

[영문]Objective : Computer aided rapid prototyping model (CARP model) is the three-dimensional model which is producing each part of human body with various materials by using data acquired from CT. In autogenous tooth transplantation surgery, CARP model can produce the tooth model and donor sites model to reduce the extra-alveolar time of donor tooth and to lead optimal contact between recipient site and donor tooth. But dimensional error of CARP model to real tooth is unknown. The purpose of this study was to evaluate dimensional error between real tooth and CARP model and 3D CT image model which is the intermediate phase of CARP model.II. Materials and Methods2 maxilla and 2 mandible block bone with teeth were taken form 2 cadaver. Computed tomography was taken in dry state block bone and in water state block bone. After CT taken, all teeth were extracted and dimension of real teeth was measured using digital caliper. Measuring dimension was mesio-distal and bucco-lingual width in crown portion and cervical portion. 3D CT image model was made with V-works 4.0 TM (Cybermed Inc., Seoul, Korea) software and measured same dimension. Then 12 teeth was selected and CARP model was fabricated. CARP model's dimension was measured and dimendional error between real tooth and 3D CT image model and CARP model was calculated. Average of absolute error was calculated and t-teat was done between real teeth and 3D CT image model. And to examine the reduction or enlargement of size of CARP model and 3D CT image model to real teeth, average of error distribution was analyzed.III. Results1) Average of absolute error between real teeth and 3D CT image model was 0.199 mm and between 3D CT image model and CARP model was 0.169 mm and between real teeth and CARP model was 0.291 mm.2) The result of t-test, average of absolute difference between dry state and wet state, maxillary teeth and mandibular teeth was significantly different between real tooth and 3D CT image model.3) 3D CT image model's size was smaller than real teeth and CARP model's size was smaller than 3D CT image model and real teeth.4) Average of size reduction between real teeth and 3D CT image model was 0.149 mm and between 3D CT image model and CARP model was 0.067 mm and total between real teeth and CARP model was 0.216 mm.IV. ConclusionWithin the scope of this study, CARP model with the 0.291 mm average of absolute error can aid to enhance the success rate of autogenous tooth transplantation due to the increased accuracy of recipient bone and donor tooth.