Histological evaluation on the biocompatibility and degradation of Poly Lactic-co Glycolic Acid(PLGA)/inorganic filler matrix in surgically created intrabony 1-wall defect in beagle dog

Abstract

[한글]치주 질환으로 인하여 소실된 치주조직을 재생시키려는 여러 술식이 많이 연구되고 있다. 그 중 bioactive factor의 적용은 치주조직의 재생에 있어서 우수한 치료법으로 평가되고 있으며, 이를 수용부에 적절히 적용하기 위한 운반체로 생체친화적인 중합체가 이용되고 있다. 본 연구의 목적은 PLGA를 inorganic filler에 혼합시킨 재료를 성견의 일벽성 골내낭에 적용하여 이 재료의 생체 친화성과 생체 흡수도를 보고자 하는 것이다.

5마리의 비글견에서 제 3 소구치를 모두 발치한 뒤, 8주간의 치유기간이 지나고 제 2 소구치 원심면과 제 4 소구치 근심면에 5mm 깊이, 4mm폭의 일벽성 골내낭을 형성하였다. 좌측 defect에는 PLGA/inorganic filler matrix를 이식하였고 우측에는 아무것도 이식하지 않은 대조군으로 나누어 술 후 8주에 희생하여 치유 결과를 조직학적으로 비교 관찰하였다.

조직학적 분석 결과, 모든 결손부에서 염증의 소견이 관찰되지 않았으며 치근흡수와 유착은 발견되지 않았다. 백악질과 치조골, 치주인대를 포함한 치주조직의 재생에 있어서 대조군, 실험군 간에 조직학적으로 치유양상에 있어 차이를 많이 보이지 않았으며 PLGA/inorganic filler matrix는 8주 내에 완전히 흡수되어 결합조직이나 신생골내에서 그 흔적을 발견할 수 없었다.

이러한 결과는 PLGA/inorganic filler matrix는 생체친화성 및 생체흡수성이 우수한 재료로서 치주 조직의 재생 치료에 있어서 신체활성인자의 scaffold로 사용될 수 있는 가능성을 보여주었다.

[영문]Regeneration of tooth supporting tissues that caused by periodontal and peri-implant tissue destruction is a major goal of reconstructive therapy. One approach to induce periodontal regeneration, bioactive growth factors have been locally applied to the root surface in order to facilitate the cascade of wound-healing events. Growth factors require appropriate scaffolds to provide long-term release of them for wound healing. The scaffolds should be biocompatible and biodegradable. It also should be space making and facilitate blood clot stabilization.

Absorbable Collagen Sponge (ACS), Poly (Lactic-co-glycolic acid) (PLGA) and other bone substitutes were introduced by researchers as scaffolds of the growth factors. The purpose of this study was to evaluate the biocompatibility and adequate degradation of newly developed PLGA/inorganic filler matrix in the surgically created 1-wall intrabony defect in the beagle dog by histological observation of 8 weeks.

Bilateral one-wall intrabony periodontal defects (mesio-distal width: 4mm, apico-coronal depth 5mm) were surgically created in the premolar region in the mandible of five dogs.

The control group was treated with conventional flap operation, and the experimental group was treated with conventional flap operation and PLGA/inorganic filler matrix application. All the animals were sacrificed after 8 weeks of healing period, and clinical and histological evaluation were performed.

All defect sites were healed uneventfully with minimal signs of inflammation clinically. In both groups, regenerated periodontal tissues including cementum, periodontal ligament were well characterized with it's property. PLGA/inorganic filler matrix were degraded within the connective tissue, and around the newly formed alveolar bone during the observation time. The histological evaluation demonstrated robust regeneration of periodontal tissues.

The application of a PLGA in the 1-wall intrabony defects showed to be biocompatible and biodegradable. Therefore use of a PLGA/inorganic filler matrix in conjunction with periodontal regeneration materials could be a good candidate for scaffold of bioactive growth factors in promoting periodontal tissue regeneration.