(A) histological study of the root resorption applying to intermittent and continuous force for incisor intrusion of dog

치의학과/석사[한글] 치아외 intrusion시 다양한 크기의 교정력을 간헐적, 지속적인 방법으로 적용하여 치근단부의 치근 흡수 정도 및 치아주위 조직 반응을 비교 관찰하고자, 성견 1마리의 상악 전치부를 각기 좌(A), 우측(B) 두군으로 나누고, 제1중절치에 15-3Ogm, 제2중절치에 50-6Og m, 측절치에 80-110gm의 힘을 각각 적용하였다. 또한 A군은 간헐적인 방법 (12시간 적용/12시간 휴식), B군은 지속적인 방법으로 적용시켜, 30일후 조직학적 검사를 하여 다음과 같은 결과를 얻었다. 1. 25gm 간헐적인 힘을 적용시킨 치아를 제외하고는 치근외 연속성이 모두 단절되었다. 2. 가해진 교정력의 증가에 비례하여 치근단 부위에서 파백아질 세포(cementoclast)와 흡수소와(resorption lacunae)등 치근 흡수 소견이 증가되었고, 골파괴 범위가 더욱 심하게 확대 되었다. 3. 같은 힘을 적용시켰을때 간헐적인 힘을 받은 치아 보다 지속적인 힘을 받은 치아에서 치근 흡수 및 골파괴 양상이 더 심하게 관찰 되었다. 4. 위의 실험 치아의 치조골은 모두 직접성 및 잠행성 골 흡수가 나타났다. [영문] The purpose of this study was to investigate the root resorption pattern in incisors in dog under intrusive orthodontic loadings of various magnitude and duration. Intrusive forces were generated by dosed coil springs. Force magnitudes were 15-30gm, 57-600 and 87-l1Ogm Durations were continuous and intermittent. Intermittent duration was applied at intervals of 12 hours. The readjustment of the force was done every 4 days. The forces were maintained for 30 days. All specimens were decalcified. embedded in paraffin and stained with hematoxylin-eosin stain. Observations were made with light microscope. The following results were obtained: 1. The continuity of root surface was ceased in all except intermittent forced teeth with 25gm. 2. The root resorptions, cementoclasts and cemental lacunae, were increased around periapical regions and the destructive score of bone was deeply extended as the experted orthodontic forces increased. 3. It was inspected that, under the same forces, root resorption and bone destruction were more deeper appeared in the continuously forced teeth than the intermittently forced ones. 4. All of the alveolar bone, showed direct and undermining bone resorptions.restrictio