体内研究0.1%纳米银溶液、氢氧化钙糊剂封药在Beagle犬慢性根尖周炎动物模型根管内的抑菌效果及对根尖周组织炎症刺激性的影响。

选取3只成年雄性Beagle犬的30颗双尖牙，拍摄锥形束CT（CBCT）确认构建慢性根尖周炎模型后按照冠向下预备法预备30颗双尖牙。将实验牙采用随机数字表法分为3组，每组10颗，分别封药0.1%纳米银溶液、氢氧化钙糊剂、空白对照（只冲洗，不封药）。根管封药4周后再次拍摄CBCT，使用CBCT机自带软件DCTViewer 2.0测量术前、术后冠状面、矢状面视图中根尖透射影像面积；处死Beagle犬，取部分牙根及根尖周组织染色，在光学显微镜下测量根管壁的抑菌深度并观察根尖周组织的炎症程度。使用SPSS 24.0统计软件对实验数据进行统计分析。

0.1%纳米银溶液组、氢氧化钙糊剂组、空白对照组犬牙根尖周透射影像面积在冠状位分别减少（4.8 ± 3.4）、（1.6 ± 1.6）和（2.2 ± 2.6）mm²，组间差异具有统计学意义（F = 5.607，P = 0.002），在矢状位分别减少（6.3 ± 3.9）、（4.1 ± 4.6）和（1.3 ± 2.8）mm²，组间差异也有统计学意义（F = 6.869，P<0.001）；根管壁的抑菌深度分别为243（159，372）、123.5（90，134）和104.5（81，135）μm，组间差异有统计学意义（χ² = 18.519，P<0.001）；0.1%纳米银溶液组根尖周组织的炎症程度3例为0级、4例为1级、3例为2级，氢氧化钙糊剂组1例0级、5例1级、3例2级、1例3级，空白对照组1例0级、3例1级、4例2级、2例3级，组间差异无统计学意义（χ² = 3.955，P = 0.052）。

0.1%纳米银溶液能够促进Beagle犬根尖周组织病变的愈合、抑制根管内细菌的生长，且对根尖周组织无明显炎症刺激性。

This in vivo study aimed to compare both antimicrobial effects and influence on periradicular tissue inflammation between nanosilver solution with calcium hydroxide during chronic apical periodontitis treatments.

The cone-beam computed tomography (CBCT) was photographed after the establishment of a chronic apical periodontitis model with 30 double fangs of 3 beagle dogs. Root canals were divided into 3 groups according to the random number table method with 10 teeth for each group, which were sealed into 0.1% nanosilver solution, calcium hydroxide paste or rinsed with 1% sodium hypochlorite alone. The dogs were harvested 4 weeks later and the CBCT was performed again, the area of lesion before and after the intracanal medicament was measured by DCTViewer 2.0; the bacteriostatic depth of root canal and the degree of inflammation of periapical tissue were measured under optical microscope after partial root and periapical tissue stained. The data from each group were compared using the SPSS 24.0 statistical software for the homogeneity of the experimental data and the normality test to compare the area of periradicular lesion, the bacteriostatic depth of root canal, the degree of inflammation of periapical tissue.

The area of periradicular lesion of the three groups decreased than before, the reduction areas were (4.8 ± 3.4) , (1.6 ± 1.6) and (2.2 ± 2.6) mm² in coronal plane with a statistically significant difference between the groups (F = 5.607, P = 0.002) . There was also statistically significant difference between the groups in sagittal plane which were (6.3 ± 3.9) , (4.1 ± 4.6) and (1.3 ± 2.8) mm², (F = 6.869, P<0.001) . The bacteriostatic depth of root canal of the three groups were 243 (159, 372) , 123.5 (90, 134) and 104.5 (81, 135) μm and there was statistically significant difference between these groups (χ² = 18.519, P<0.001) . The inflammation degree of three samples were 0, four samples were 1 and three samples were 2 in the group of 0.1% nanosilver solution. The degree of one sample in calcium hydroxide paste group was 0, five samples were 1, three samples were 2 and one sample was 3, while in the blank group the degree of one sample was 0, three samples were 1, four samples were 2, two samples were 3 with no statistically difference between the groups (χ² = 3.955, P = 0.052) .

0.1% nanosilver solution could promote the healing of periradicular lesions more effectively, had bacteriostasis more effectively in root canal and no significant inflammatory response on periapical tissue.