Basic Research for Aetiology and Pathology of Periodontal Disease

根据微生物学研究，有充分的证据表明，以革兰氏阴性厌氧棒为主的龈下菌斑与破坏性牙周病有关。本研究以羟丙基纤维素（HPC）为基材，尝试将药物直接涂在龈下菌斑上，含1%四环素（TC）的羟丙基纤维素（HPC）形成固体弹性条。从这些试纸中释放出的药物显示，几乎100%的物质被释放。从本研究获得的临床结果来看，插入安慰剂贴片后，牙龈指数、探诊深度和探诊时出血倾向于减少。微生物学研究结果表明，含有HPC的TC有效地改变了龈下菌斑的微生物组成。这种以HPC为基础材料的直接给药系统可以有效地改变龈下菌斑中细菌的组成，并产生临床改善的迹象。需要注意的是，局部使用四环素可能会对牙龈下菌群造成不良影响。Mandel等人（1986）表明，在感染放线菌的牙周袋中局部应用四环素实际上可以导致这些袋中的菌群转变为几乎纯的放线菌培养物，这与牙周组织的活跃破坏期有关。这可能是由于放线菌杆菌侵入牙龈结缔组织并在这些组织中存活，重新播种了四环素抑制袋。

Based on the microbiological studies, it is well documented that the subgingival plaque, in which the gram-negative anaerobic rods are predominant, is associated with the destructive periodontal disease. In this investigation, we used hydroxypropylcellulose (HPC) as the base material and tried to apply the drugs directly to the subgingival plaque, the HPC containing 1% tetracycline (TC) formend solid and elastic strips. The in vitro release of the drugs from these strips showed almost 100% of this material added was released. From the clinical results obtained in this study, it was found that gingival index, probing depth and bleeding on probing tended to be less when the placebo strips were inserted. The results obtained from the microbiological studies showed that the TC containing HPC altered effectively the microbiological composition of the subginigival plaque.This new direct drug delivery system with HPC used as a base material was found to be effctive in changiang the composition of bacteria in the subgingival plaque and inproducing signs of clinical improvement.A note of caution should be added concerning the possible adverse in the subgingival flora which can be brought about by locally delivered tetracycline. Mandel et al. (1986) have shown that locally applied tetracycline in periodontal pockets infected with actinobacillus actinomycetemcomitans can actually result in a shift in the flora of such pockets to almost pure cultures of A. actinomycetemcomitans, associated with a period of active periodontal tissue destruction. It is likely that this results from re-seeding of the tetracycline-suppressed pocket by A.actinomycetemcomitans, which has invaded the gingival connective tissue and which remains viable in these tissue.