牙体与充填体间微隙对微生物致龋影响的实验研究

Effect of gap size between tooth and restorative materials on microbiolism based caries in vitro

目的体外建立经变形链球菌致龋的人工龋模型，评价牙与充填体间微隙大小对微生物致龋的影响。方法用无龋磨牙制备的牙块和形态大小相同的复合树脂块制作二者间隙分别为0、25、50、100、190及250um的6个实验组样本，对照组样本使用粘接剂粘接牙面和复合树脂，6个实验组及对照组每组各8个样本，共56个样本经14d变形链球菌连续培养后切片，采用激光共聚焦扫描显微镜（confocal laser scanning microscope，CLSM）检测牙体洞外表面龋损及洞壁龋损的脱矿程度，分别测定龋损最大深度、最大长度、荧光面积及平均荧光量等参数并进行统计学分析；扫描电镜观察界面微隙内沉积物与龋损形成情况。结果CLSM和扫描电镜观察显示，除2个对照组样本未形成洞壁龋损外其余样本均形成了不同程度的洞外表面龋损和洞壁龋损；各组表面龋损脱矿程度差异均无统计学意义（P〉0．05）。190um组及250um组洞壁龋损最大深度[分别为（1145．37±198．98）、（1190.12±290．80）um]、最大长度、荧光面积及平均荧光度均显著高于0、25、50及100um组[龋损最大深度分别为（205．25±122．61）、（303．87±118．80）、（437．75±154．88）、（602．87±269．13）um]，差异均有统计学意义（P〈0．01），脱矿程度随微隙增加而加重；而0、25、50um组洞壁龋损最大深度、最大长度及荧光面积差异均无统计学意义。结论体外牙与充填体间的微隙大于100um时提示洞壁龋损有明显进展；微隙的存在是影响牙与充填体间微生物致龋的重要因素。

Objective To evaluate the effect of gap size between tooth and restorative materials on microbiolism based caries in vitro. Methods Tooth blocks made of human molars without caries and the same size composite resin blocks were selected and prepared. Tooth-resin matrix was mounted on resin base with a gap size of 0, 25, 50, 100, 190, 250 um and a control group was dealed with adhesive system. Six experimental groups and one control group were included, with 8 samples in one group and a total of 56 samples. The samples were cultured by a 14-day sequential batch culture technique. The development of outer surface lesion and wall lesion was assessed with confocal laser scanning microscope （CLSM） by measuring the maximum lesion depth, fluorescence areas and average fluorescence value. The data were collected and statistically analyzed. The deposits of the tooth-restoration interface and the development of the carious lesion were observed by scanning electron microscope （SEM）. Results Most groups showed outer surface lesion and wall surface lesions observed by CLSM and SEM except 2 samples in control group. There was no significant difference on the outer surface lesion （P 〉 0. 05 ）. The maximum lesion depth [ （ 1145.37 ± 198.98）, （ 1190. 12 ± 290. 80） um respectively ], the maximum lesion length, fluorescence areas and average fluorescence value of 190 and 250 um groups＇ wall lesions were significantly higher than the 0, 25, 50 and 100 um groups [ the maximum lesion depth was （205.25 ± 122. 61 ）, （303.87 ± 118.80）, （437.75 ± 154. 88 ）, （602. 87 ± 269. 13 ） um respectively ], P 〈 0. 01. With the increase of the gap size, the demineralization developed more seriously. While the maximum lesion depth, the maximum lesion length and fluorescence areas of 0, 25, 50 um groups＇ wall lesions were of no significant difference. Conclusions There was close relationship between gap size and wall lesion when the gap was above 100 um at tooth-composite resin interface. The existence of gap was the main influencing factor on the development of microbiolism based caries lesion.