种植体间距与种植体周炎关系的实验研究

Relationship between inter-implant distances and peri-implantitis:An experimental study in the dog

目的:探究不同种植体间距与种植体周炎发生的关系。方法:拔除6只比格犬的双侧下颌第二前磨牙至第一磨牙,拔牙后8周在数字化外科导板辅助下行种植术。每侧植入连续的4枚种植体,种植体间距分别设置为1、2、3 mm,共3个组别。术后2周和3个月时记录种植体周临床牙周指数,术后3个月时采集种植体龈周菌斑行16S rRNA基因测序,分别于术后1、2、3个月时拍摄X线平行投照根尖片进行影像学测量;术后3个月时进行取材,制作硬组织切片并行Van Gieson(VG)染色,用SPSS 25.0软件作统计学分析。结果:1 mm组的种植体周探诊深度(probing depth,PD)、探诊出血(bleeding on probing,BOP)阳性率、菌斑指数(plaque index,PI)均明显高于2 mm组和3 mm组;1 mm组中,满足PI≥2的检测位点数最多,且符合种植体周炎诊断标准的PD≥5 mm或BOP阳性检测位点数明显高于其他2组。菌斑群落结构分析显示,1 mm组密螺旋体属(Treponema)、坦纳菌属(Tannerella)和普氏菌属(Prevotella)的相对丰度较3 mm组更高。X线片结果显示,1 mm组边缘骨吸收(marginal bone resorption,MBR)与嵴顶骨吸收(crestal bone resorption,CBR)明显大于其他2组。组织学观察结果显示,3组中,1 mm组骨嵴顶高度较其他2组明显降低。2 mm组与3 mm组比较,以上指标的差异均无统计学意义。结论:相对于2 mm组和3 mm组,1 mm组PI最高,且发生了明显的骨吸收和软组织炎症,而2 mm组和3 mm组没有发生明显的骨吸收。因此,1 mm的种植体间距更容易发生种植体周炎。

Objective:To evaluate whether the incidence of peri-implantitis was associated with adjacent implants inserted at different inter-implant distances.Methods:The bilateral mandibular teeth from second premolar to first molar of 6 beagle dogs were extracted.After tooth extraction for 8 weeks,the implants were placed with the help of a digital surgical guide.Each dog received 4 implants in the hemimandible.Implants were placed so that 3 inter-implant distances were created at 1,2,3 mm group.The peri-implant clinical periodontal indexes were recorded at the time of 2 weeks and 3 months after implant placement.Samples from peri-implant soft tissue were collected and analyzed by sequencing the bacterial 16S rRNA gene.X-ray parallel projection radiographs were taken for imaging measurement at the time of 1,2,3 months after implant placement.After 3 months of dental implantation,the mandibular bones were retrieved.The sections were stained with Van Gieson(VG)dye solution.Statistical analysis was performed with SPSS 25.0 software.Results:The indexes of probing depth(PD),bleeding on probing(BOP)and plaque index(PI)of 1 mm group were significantly higher than 2 mm and 3 mm groups.The frequencies of the sites about PI≥2 were significantly the highest in 1 mm group,and so were the sites about PD≥5 mm or BOP(+)meeting the criteria of peri-implantitis.The analysis of the microbial community structure showed that the relative abundance of Treponema,Tannerella and Prevotella in 1 mm group was higher than that in 3 mm group.Statistically significant differences were found in regard to marginal bone resorption(MBR)and crestal bone resorption(CBR)in comparing 1 mm group with the other two groups by X-ray examination.Histological observation revealed that 1 mm group showed lower crest bone position than the other two groups.There were no significant differences between 2 mm and 3 mm groups in the above results.Conclusion:This study demonstrates that peri-implantitis is more likely to happen in 1 mm inter-implant distance than that in 2 mm and 3 mm distances.1 mm distance group showed the highest PI and significant bone resorption and soft tissue inflammation,while no significant bone resorption happened in 2 mm and 3 mm distance group.