正畸应力刺激下Beagle犬微种植体周围炎的牙周组织变化

Periodontal tissue changes in a Beagle dog model of peri-implantitis under orthodontic force

背景:种植体周围炎早期阶段的进展是影响种植体稳定性的重要因素。目的:建立正畸应力刺激下的微种植体周围炎动物模型,对微种植体周围炎进展的不同阶段进行牙周指标评价。方法:取成年雄性Beagle犬8只(四川大学华西实验动物中心提供),采用助攻法将48只纯钛微种植钉随机植入Beagle犬双侧上颌第二、三、四前磨牙的根分叉区,随机选择一侧植入3枚丝线结扎的微种植体(实验组),分别在丝线结扎诱导微种植体周围炎后的第1,2,3,4周即刻施加100 g拉力(每个时间点2只犬),各持续加力1个月;对侧植入3枚微种植体(不加力)作为对照。诊断微种植体周围炎的发生情况,评估微种植体周围炎进展不同阶段的改良菌斑指数、改良龈沟出血指数、牙周探针深度及微种植体松动度。结果与结论:(1)实验组微种植体均表现为表面有菌斑或软垢积聚,软组织充血、肿胀、质地松软,有时伴有增生,甚至发生黏膜糜烂、溃疡,检查探诊出血,探诊深度增加,少数微种植体松动,判定为微种植体周围炎;对照组牙龈健康,无颜色改变,无水肿或肿胀,探诊龈沟后不出血;(2)实验组中,4加力组间改良菌斑指数、牙周探针深度两两比较差异均有显著性意义(P <0.05),4加力组间改良龈沟出血指数比较差异无显著性意义(P> 0.05);(3)植入的48枚微种植体有3枚松动,其余均为稳定;松动的3枚均为实验组,其中Ⅰ度松动1枚,Ⅱ度松动2枚;(4)结果表明在正畸应力刺激下,于微种植体周围炎发展的不同阶段,随着时间的增加,微种植体周围的改良菌斑指数、牙周探针深度值与时间呈正相关,提示在微种植体周围炎发展过程中进行早期干预是预防微种植体周围炎的重要措施。

BACKGROUND:The early-stage progression of peri-implantitis is an important factor affecting the stability of micro-implants.OBJECTIVE:To establish an animal model of peri-implantitis under orthodontic force,and to evaluate periodontal indexes in different stages of the development of peri-implantitis.METHODS:Eight adult male Beagle dogs were provided by the Experimental Animal Center of Sichuan University in China.Forty-eight micro-implants were randomly implanted into the maxillary interradicular region at the center of the mesial and distal roots of bilateral second,third,and fourth premolars of Beagle dogs.One side served as experimental group with three loaded micro-implants under 100 g of orthodontic force at 1,2,3,4 weeks of peri-implantitis,and the force lasted for 1 month.The contralateral side acted as control group with no orthodontic force.Two dogs were selected at each visit time.Incidence and development of peri-implantitis were evaluated based on the periodontal indexes such as modified plaque index,modified sulcus bleeding index,periodontal probe depth,and micro-implant looseness.RESULTS AND CONCLUSION:(1)In the experimental group,plaque or soft scale accumulation on the micro-implant surface formed,with soft tissue congestion and swelling.Sometimes hyperplasia and even mucosal erosion,ulceration developed as well as bleeding occurred during the probing.With the increase of probe depth,a few of micro-implants were loosened.All of these indicated the occurrence of peri-implantitis.In the control group,no color change,no edema or swelling,and no bleeding after probing appeared,and the gingiva was in health status.(2)In the experimental group,there were significant differences in the modified plaque index and periodontal probe depth at different visit time(P<0.05),while no significant difference was visible in the modified sulcus bleeding index(P>0.05).(3)Only 3 of 48 micro-implants were loosened,which belonged to the experimental group,including one of degree I and two of degree II.To conclude,with the stimulation of orthodontic stress,the modified plaque index and periodontal probe depth values around the micro-implant are positively related to the different stages of the development of the peri-implantitis.This indicates that early intervention under the orthodontic force is an important measure to prevent peri-implantitis during the development of peri-implantitis.