Predominant obligate anaerobes in secondary carious lesions around restorative materials

在这项研究中，我们试图通过严格的厌氧程序分离和鉴定修复材料周围继发性龋齿中的优势可培养菌群。牙菌斑采集于复合树脂和银汞合金周围的继发龋表面。复合树脂和银汞合金处理的3个菌斑样品中所有可培养菌的CFU计数范围分别为2.73*10^8 ~ 8.72*10^9和7.92*10^5 ~ 8.02*10^8。链球菌和乳酸杆菌的数量占所有可培养细菌的1/100 ~ 1/3。复合树脂组与银汞合金组细菌总数中链球菌和乳酸菌计数无显著差异。样品取自3颗复合树脂修复牙和2颗银汞合金修复牙的牙本质。除1例专性厌氧菌占22.7%外，其余4例均为优势专性厌氧菌占总数的73.4% ~ 100%。复合树脂组48株菌株中，兼性厌氧菌为链球菌4株、放线菌1株，专性厌氧菌为胃链球菌13株、活动菌21株、蜘蛛菌6株、真杆菌、双歧杆菌和丙酸杆菌各1株。139株汞齐组中兼性厌氧菌为链球菌64株、放线菌9株、乳酸菌2株；专性厌氧菌为胃链球菌27株、链球菌4株、放线菌17株、真杆菌2株、乳酸菌和丙酸菌各1株、细孔菌12株。结果表明，继发性龋齿的主要可培养菌群特征介于牙菌斑和原发性龋齿牙本质之间。然而，复合树脂周围的细菌与汞合金周围的细菌没有本质差异。

In this study, we attempted to isolate and identify the predominant cultivable flora in secondary caries around restorative materials by strict anaerobic procedures.The samples of dental plaque were taken from the surfaces on secondary caries around composite resin and amalgam. The range of CFU counts for all cultivable bacteria taken from each of 3 plaque samples on composite resin and amalgam was respectively 2.73*10^8 to 8.72*10^9 and 7.92*10^5 to 8.02*10^8. The number of Streptococci and Lactobacilli accounted for 1/100 to 1/3 of all cultivable bacteria. However, there was no significant difference in Streptococci and Lactobacilli counts of total bacterial counts between composite resin group and amalgam group.The samples were taken from secondary carious dentin around 3 teeth restored with composite resin and 2 teeth restored with amalgam. The rates of predominant obligate anaerobes were 73.4% to 100% of total isolates in 4 cases, except that the rate of obligate anaerobes was 22.7% in one case.Of 48 isolates of composite resin group, the facultative anaerobes were 4 strains of Streptococcus and 1 strain of Actinomyces, while the obligate anaerobes were 13 strains of Peptostreptococcus, 21 strains of Actionomyces, 6 strains of Arachnia and 1 strain each of Eubacterium, Bifidobacterium and Propionibacterium. Of 139 isolates of amalgam group, the facultative anaerobes were 64 strains of Streptococcus, 9 strains of Actinomyces and 2 strains of Lactobacillus, while the obligate anaerobes were 27 strains of Peptostreptococcus, 4 strains of Streptococcus, 17 strains of Actinomyces, 2 strains of Eubacterium, 1 strain each of Lactobacillus and Propionibacterium, and 12 strains of Veillonella.The results suggested that the predominant cultivable flora in secondary carious lesions had characterization intermediate between dental plaque and primary carious dentin. However, the bacteria around composite resin were not substantially different from those around amalgam.