Olson R H, Adams D F, Layman D L
J Periodontol. 1985 Oct;56(10):592-6. doi: 10.1902/jop.1985.56.10.592.
Cementum shavings obtained from periodontally diseased and nondiseased areas of 100 removed, single-rooted teeth were extracted with either pyrogen-free water (PFW) for 5 minutes, 1 M citric acid for 5 minutes or 45% phenol-PFW for 90 minutes at 65 degrees C. The extracts were membrane-filtered, dialyzed exhaustively versus PFW, lyophilized, weighed and then dissolved in complete growth medium. The phenol-water or citric acid extracts of cementum shavings from periodontally diseased roots were positive for endotoxin by the limulus lysate assay (LLA). Pyrogen-free water extracts of diseased or phenol-water extracts of nondiseased cementum shavings were negative, or only slightly positive, respectively, for endotoxin by LLA. Media containing the various extracts were added to logarithmically growing cultures of human gingival fibroblasts (HGF). Separate cultures of HGF were exposed to Escherichia coli endotoxin at concentrations of 50, 100, 250 and 500 micrograms/ml to determine the growth-inhibitory effects of a known endotoxin. Cell growth was analyzed by measuring the incorporation of tritiated thymidine into cells. Suppression of HGF growth from 30 to 49% by E. coli endotoxin was concentration-dependent and linear over the concentration range of endotoxin tested. Pyrogen-free water extracts of diseased (endotoxin negative) or phenol-water extracts of nondiseased cementum shavings (slightly endotoxin positive) did not effect HGF growth. However, citric acid or phenol-water extracts of diseased cementum shavings (highly endotoxin positive) significantly suppressed HGF growth 58% and 61%, respectively. These results indicate that citric acid is effective in removing cytotoxic substances, presumably endotoxin, from cementum shavings and suggest that citric acid treatment is effective clinically in detoxifying periodontally diseased root surfaces.
从100颗拔除的单根牙的牙周病损区和非病损区获取牙骨质刨屑，分别用无热原水（PFW）提取5分钟、1M柠檬酸提取5分钟或45%苯酚-PFW在65℃提取90分钟。提取物经膜过滤，与PFW充分透析，冻干，称重，然后溶解于完全生长培养基中。用鲎试剂法（LLA）检测牙周病牙根牙骨质刨屑的苯酚-水提取物或柠檬酸提取物中的内毒素呈阳性。病损牙骨质刨屑的无热原水提取物或非病损牙骨质刨屑的苯酚-水提取物用LLA检测内毒素分别为阴性或仅轻微阳性。将含有各种提取物的培养基加入对数生长期的人牙龈成纤维细胞（HGF）培养物中。将HGF的单独培养物暴露于浓度为50、100、250和500微克/毫升的大肠杆菌内毒素中，以确定已知内毒素的生长抑制作用。通过测量氚标记胸腺嘧啶核苷掺入细胞中来分析细胞生长。在测试的内毒素浓度范围内，大肠杆菌内毒素对HGF生长的抑制率为30%至49%，呈浓度依赖性且呈线性关系。病损牙骨质刨屑的无热原水提取物（内毒素阴性）或非病损牙骨质刨屑的苯酚-水提取物（内毒素轻微阳性）对HGF生长无影响。然而，病损牙骨质刨屑的柠檬酸提取物或苯酚-水提取物（内毒素高度阳性）分别显著抑制HGF生长58%和61%。这些结果表明柠檬酸能有效去除牙骨质刨屑中的细胞毒性物质，推测为内毒素，并提示柠檬酸处理在临床上对牙周病牙根面解毒有效。
