STUDY ON ADHERENCE ABILITY OF PERIODONTAL PATHOGENS AND CARIOGENIC BACTERIA TO HYDROXYAPATITE DISKS

Objective To study the adherence activity of six representative periodontopathic and cariogenic bacteria to hydroxyapatite disks. Methods Six periodontopathic and cariogenic bacteria of P. gingivalis, A. actinomycetemcomitans, F. nucleatum, S. sanguis, A. viscosus and S. mutans were cultured in modified MD-300 chemostat according to total fifteen experimental groups of single-specie and each pair of periodontal pathogens and cariogenic bacteria, respectively. After 1h attached live bacteria on removable hydroxyapatite disks was analyzed by culture technologies to evaluate the adherence level. Results The adherence activity of periodontopathic and cariogenic bacteria to HA was in the following order: S. sanguis > A. viscosus> S. mutans> A. actinomycetemcomitans > F. nucleatum > P. gingivalis. The number of periodontopathic bacteria to HA was enhanced by S. sanguis and A. viscosus,respectively.When mix-cultivated with S. mutans, the colonization of P. gingivalis was reduced significantly(P<0.001). Periodontopathic bacteria had no effect on the adherence activity of S. mutans and A. viscosus, except S. sanguis. Conclusion It was showed that the adherence activity of periodontal pathogens was weaker than that of cariogenic bacteria and emphasized the importance of bacterial adherence in determining the level of bacterial colonization on tooth surfaces. It was suggested that periodontopathic bacteria can utilize initial colonizers to become those predominant bacteria in periodontal ecosystem, which maybe have close relation to the periodontopathic mechanism.

牙周致病菌和致龋菌对羟基磷灰石的附着能力

目的研究牙周致病菌和致龋菌对羟基磷灰石(HA)的附着能力。方法将与牙周病和龋病发生密切相关的6种国际参考标准菌株(牙龈卟啉单胞菌、伴放线放线杆菌、具核梭杆菌、变形链球菌、血链球菌、黏性放线菌),分别接种于模拟口腔环境的改良MD-300恒化器中培养,1 h后分离培养HA表面附着的细菌,检测各菌种对HA的附着能力及其相互作用。结果检测菌种中,血链球菌对HA的附着能力最强,其他依次为黏性放线菌、变形链球菌、伴放线放线杆菌、具核梭杆菌和牙龈卟啉单胞菌。血链球菌和黏性放线菌均能增强牙周致病菌对HA的附着能力,变形链球菌降低牙龈卟啉单胞菌的附着能力;所有牙周致病菌均降低血链球菌对HA的附着能力,而对变形链球菌和黏性放线菌无明显影响。结论牙周致病菌对HA的附着能力明显弱于致龋菌,其借助早期定植菌成为牙周生态系的优势菌和牙周病的主要病原菌。

牙周致病菌和致龋菌间生长关系的体外动态观察

目的研究6种代表性牙周致病菌和致龋菌在菌斑生物膜和悬浮液中的消长关系。方法将双菌组(致龋菌+牙周致病菌)接种于改良恒化器中,连续培养1h、24h、48h和96h,然后取在羟基磷灰石表面形成的生物膜和悬浮液再进行细菌培养。结果与血链球菌混合培养时,菌斑生物膜和悬浮液中牙周致病菌均增多,而血链球菌明显减少(P<0.05);具核梭杆菌与变形链球菌培养时,菌斑生物膜和悬浮液中具核梭杆菌明显增多,而变形链球菌减少(P<0.05)。菌斑生物膜中致龋菌占优势,相应的悬浮液中牙周致病菌96h开始占优势。悬浮液中细菌量波动更明显。结论2类致病菌在菌斑生物膜与相应的悬浮液中的生长是不一致的。2类致病菌之间相互作用也许是决定菌斑生物膜内部生态环境发展方向的主要因素。

厚朴提取物对于4种常见口腔致病菌生长和黏附的作用

目的研究生药厚朴提取物(MOCE)及其主要成分厚朴酚与和厚朴酚对于常见口腔致病菌生长和黏附的影响。方法选取2种致龋菌和2种牙周病致病菌作为实验菌株,用杯碟法和溶液稀释法分别考察其对4种口腔致病菌的最小抑菌浓度(MIC)和最小杀菌浓度(MBC),并考察杀菌速率;另建立黏附实验模型,考察药物对于致龋菌的黏附抑制作用,及其对已形成黏附的脱附作用。结果 MOCE对于4种实验菌株的MIC、MBC值均小于100μg.mL-1,而且具有突出的速效杀菌特点:1 mg.mL-1MOCE 30 s内速效杀菌达99%以上,在MBC浓度下仅5 min即已表现出明显杀菌作用(>90%);对于致龋菌的黏附抑制,最小有效浓度为6.25～25μg.mL-1(随菌种的不同而不同),且该浓度下对已形成的黏附具有脱附作用。结论 MOCE对4种口腔致病菌的生长具有较强抑制作用,速效杀菌,并对致龋菌的黏附具有抑制形成和促进瓦解的双效作用,在口腔用药和保健领域具有重要价值。

致龋菌与牙周致病菌混合感染动物模型的初步研究

目的通过建立龋病与牙周病共同发生的动物模型,初步探讨致龋菌与牙周致病菌的相关性。方法 56周龄金黄地鼠22只,雌雄各半,随机分成2组,均给予高蔗糖饮食。对照组10只,感染组12只,双侧下颌第一磨牙丝线结扎,接种牙龈卟啉单胞菌（P.g）和变形链球菌（S.m）;种菌结束后8周检查下颌第一磨牙牙体和牙周组织损害情况。结果感染组产生明显的牙周损害：探诊出血（BOP）、菌斑指数（PLI）以及牙槽骨吸收（ABL）均显著大于对照组（P〈0.01）,同时,感染组冠部龋坏率达到90.0%,大于对照组（66.7%）,但差异没有统计学意义。2个组均未产生根龋。结论牙龈卟啉单胞菌与变形链球菌分别作用于牙周和牙体组织发生龋及牙周损害,二者没有显著的相互抑制作用,可在地鼠口腔中同时出现龋和牙周炎病损的模型。