Calcium aluminate 골시멘트가 백서 두개골 결손부 치유에 미치는 영향

Abstract

[한글]

우수한 생체 친화 능력과 기계적인 특성을 접목시켜 개발한 calcium aluminate (CaO․Al2O3, CA) 시멘트의 생체 적용 효과를 알아보기 위해 백서 두개골 8㎜ 원형 결손부에 다음과 같은 calcium aluminate cement (CAC)를 이식하였다. 실험 1군에는 3.5㎛ 입자의 CAC를, 실험 2군에는 212㎛～250㎛ 입자의 CAC를, 실험 3군에는 LiF-maleic acid가 첨가된 calcium aluminate 골시멘트 (LM-CA 골시멘트), 실험 4군에는 polymethylmethacrylate (PMMA)와 calcium aluminate를 혼합한, CA-PMMA 골시멘트를 이식하였다. 술후 2주, 8주에 희생하고 치유 결과를 조직학적으로 비교 관찰하여 다음과 같은 결과를 얻었다.

1. 대조군은 2주에서 염증 세포가 관찰되었고, 8주에는 골막과 경막이 연속적으로 이어져 있었으나 결손부의 중앙부는 성긴 결합조직에 의해 채워져 있었다.

2. 실험 1군 (212㎛～250㎛ 입자)은 2주에서 골성 조직으로 둘러싸인 미성숙골이 형성되어 있었고, 최외층은 골성 조직이 둘러싸고 있었다. 미성숙골과 골성 조직 사이에는 조골 세포가 줄지어 배열되어 있었으며, 골성 조직은 8주에도 잔존하였다.

3. 실험 2군 (3.5㎛ 입자)은 2주에서 골막과 경막의 연속성이 상실되고 calcium aluminate 입자의 분산과 염증 세포의 침윤을 확인할 수 있었으며, 이러한 소견은 8주에서 더욱 심화되었다.

4. 실험 3군에서 이식재와 잔존골과의 결합이 나타났으며, 술후 2주보다 8주에서 증가되었다. 또한 2주, 8주 모두에서 이식재 입자의 분산과 염증 세포의 침윤을 확인할 수 있었다.

5. 실험 4군은 이식재 자체의 체적 안정성 (dimensional stability)을 나타냈으며, 잔존골과의 결합 양상은 술후 2주, 8주 모두에서 나타나지 않았다. 이식재는 섬유성 결합조직에 의해 피막화되어 잔존골과 분리되어 있었고, 이식재 주위로 염증 세포의 침윤을 확인할 수 있었다.

이상의 결과에서 볼 때, 백서 두개골 결손부에 212㎛～250㎛ 입자의 calcium aluminate 시멘트를 적용한 경우 주변 조직의 성장과 치유에 있어 생체 친화적인 재료이다. LM-CA 골시멘트는 잔존골과의 결합능력이 있어 생체활성 골이식재로, CA-PMMA 복합 골시멘트는 체적 안정성을 지녀 골 부피 증대를 위한 이식재로 개발 가능할 것으로 사료된다.

[영문]

This present study was carried out to find the effects of calcium aluminate cement (CaO․Al2O3, CAC), which has been developed with bio-compatibility and mechanical properties, in biological environments. The purpose of this study was to evaluate histologically the effect of CAC on the healing of calvarial defect in Sprague-Dawley rats. The rats were divided in five groups : In the control group, nothing was applied into the defect of each rat. Two different particle sizes of CAC -212～250㎛ and 3.5㎛-were filled in the experimental group 1 & 2 respectively. LiF-maleic acid contained calcium aluminate bone cement (LM-CA bone cement) was implanted in the experimental group 3 and polymethylmethacrylate (PMMA) contained calcium aluminate bone cement (CA-PMMA composite bone cement) was implanted in the experimental group 4. Rats were sacrificed at 2, 8 weeks after surgical procedure. The specimens were examined by histologic analysis, especially about the bone-cement interface and the response of surrounding tissue. The results are as follows;

1. In the control group, inflammatory cells were observed at 2 weeks. At 8 weeks, periosteum and dura mater were continuously joined together in the defect areas. But in the center of defect area were filled up with the loose connective tissues.

2. In the experimental group 1 (212㎛～250㎛ particle), immature bone surrounded by osteoid layer was formed and outermost layer was surrounded by osteoid layer at 2 weeks. Osteoblasts were arranged between immature bone and osteoid layer. And, osteoid layer was remained until 8 weeks after surgery.

3. In the experimental group 2, periosteum and dura mater lost its continuity at 2 weeks. Scattering of CAC particles and infiltration of inflammatory cells were observed, which this findings deepened at 8 weeks.

4. In the experimental group 3, the bonding between implanted bone cement and the existing bone was seen, which more increased in 8 weeks than 2 weeks. Inflammatory infiltration and the dispersion of implanted bone cement particles were seen in both 2 weeks and 8 weeks.

5. In the experimental group 4, implanted bone itself had a dimensional stability and no bonding between implanted bone cement and the existing bone was seen in both 2 weeks and 8 weeks. Implanted bone cement was encapsulated by fibrous connective tissue. In addition, inflammatory infiltration was seen around implanted bone cement.

The result of this study shows that when calvarial defects in white rats are filled with calcium aluminate cement of 212～250㎛, the materials are to be bio-compatible in growth and healing on surrounding tissues. On the basis of these results, when LM-CA bone cement or CA-PMMA composite bone cement was implanted in rat calvarial defect, LM-CA bone cement can be used as a bioactive bone graft material due to ability of bonding to the existing bone and CA-PMMA can be used as a graft material for augmentation of bone-volume due to dimensional stability. When further researches are fulfilled, such as direct bone adhesion and bone regeneration ability, it''s possible that CAC could be applied to various periodontology fields in the future.