不同根管预备长度对正常和免疫抑制大鼠感染根管形成根尖生物膜的影响

发布时间：2018-04-13 12:09

  本文选题：根尖周炎 + 根尖生物膜　； 参考：《重庆医科大学》2017年硕士论文

【摘要】：根管治疗是治疗根尖周炎的首选方法,即在治疗中最大程度的清除根管内感染,并进行严密的三维充填以防止再感染。少数的患牙,即使进行了标准规范的根管治疗,根尖周炎仍迁延不愈,我们通常将此称为难治性根尖周炎。根尖生物膜被认为是导致难治性根尖周炎的重要原因。对于牙周健康的患牙,根尖生物膜来源于感染根管已达成共识。但根管内的细菌是在环境因素的诱导下主动溢出根尖孔,还是受挤压而溢出根尖孔形成根尖生物膜仍存在争议。为了研究根尖生物膜的形成原因,本课题组前期实验进行了体外研究,表明只有根管全长预备和超预备状态下,才在根尖周检测到细菌及根尖生物膜。但体外实验忽略了机体的免疫反应。根尖周炎的病理反应与机体的免疫反应密不可分,而根尖周细菌形成根尖生物膜又与根尖周的免疫炎症反应可能有着一定联系。本实验将建立免疫抑制大鼠模型和大鼠感染根管动物模型,对免疫正常组和免疫抑制组进行不同长度的根管预备,以观察不同根管预备长度及免疫抑制对根尖生物膜形成的影响。为临床工作中预防难治性根尖周炎的形成提供理论依据。目的:建立感染根管大鼠模型和免疫抑制大鼠模型,探讨不同根管预备长度对免疫正常和免疫抑制大鼠感染根管形成根尖生物膜的影响。材料和方法1、建立免疫抑制大鼠模型:54只大鼠分为免疫正常组(n=27)和免疫抑制组(n=27)。免疫抑制组腹腔注射环磷酰胺50mg/kg,1周1次,以建立免疫抑制动物模型。2.建立感染根管大鼠模型:免疫正常组随机分为对照组A(n=3),实验组B、C、D、E(均n=6);免疫抑制组均随机分为对照组a(n=3),实验组b、c、d、e(均n=6)。对照组不做处理。实验组双侧上颌第一磨牙均行开髓处理。开髓后髓腔暴露于口腔环境中正常饲养4周,以建立感染根管动物模型。3.根管干预:B、b组开髓后不做任何处理。C、c组双侧上颌第一磨牙近中根管行根管预备至根管上2/3工作长度。D、d组双侧上颌第一磨牙近中根管行根管预备至全长。E、e组双侧上颌第一磨牙近中根管超出根管工作长度1毫米预备。根管预备后第7天和21天,每组均分别处死3只大鼠,取左侧上颌第一磨牙近中牙根表面组织进行PCR检测,取右侧上颌第一磨牙近中牙根用于扫描电镜,观察是否形成根尖生物膜。结果:根管预备后第7天和21天,全长组(D、d组)及超长组(E、e组)根尖区样本扩增出16Sr DNA特异性引物片段,对照组(A、a组)、开髓组(B、b组)及2/3干扰组(C、c组)均未检测到。根管预备后第7天,A、a组样本的根尖区均可见大量胶原纤维覆盖于牙根表面,未见暴露的牙骨质及吸收陷窝。而B、C、D、E、b、c、d、e组近中牙根根尖区在扫描电镜下均未观察到细菌生物膜的存在,但根尖区牙骨质表面暴露,牙根表面几乎没有胶原纤维覆盖,并可见许多牙骨质吸收陷窝。根管预备后第21天,E组中仅有一例样本观察到小范围细菌生物膜存在,主要由杆菌组成,周围包裹有少量无定型基质样物质。其余组与根管预备后第7天一致。结论:1.成功建立免疫抑制大鼠模型和感染根管大鼠模型。2.在机体免疫机制作用下,根管全长预备和超长预备对细菌溢出根尖孔有促进作用,但没有证据表明对根尖生物膜的形成有促进作用。
[Abstract]:Root canal therapy is the preferred method for the treatment of periapical periodontitis, namely in the treatment of the maximum removal of root canal infection, and rigorous three-dimensional filling to prevent reinfection. A few teeth, even if the Standard Specification for root canal therapy, periapical periodontitis is still persistent, we usually refer to this refractory periapical lesions. Periapical biofilm is considered to be an important cause of refractory periapical periodontitis. The periodontal health of the teeth with periapical biofilm from the infected root canal has been reached. But the root canal bacteria is induced by environmental factors under active overflow apical or by extrusion and overflow of root tip the hole formation of periapical biofilm is still controversial. In order to research on the causes of periapical biofilm, ourprevious experiments were carried out in vitro study showed that only the length of root canal preparation and preparation of super state, was detected in the periapical bacteria And periapical biofilm in vitro. But ignore the body's immune response. Closely related to pathological reaction and immune response of periapical periodontitis, and periapical periapical biofilm forming bacteria and inflammation periapical may have some contact. This experiment will establish the Immunosuppressive Model in rats and rats infected root canal the animal model of root canal preparation on immune normal group and immunosuppressed group of different length, in order to investigate the effect of different root canal length and immunosuppression on periapical biofilm formation. To provide a theoretical basis for clinical work in the prevention of the formation of refractory periapical periodontitis. Objective: to establish rat model and immune tube suppression the rat model of infected root canals of different length of the inhibitory effect of rat periapical biofilm formation of infected root canal of normal immune and immune. Materials and methods 1, the establishment of rat model of immune suppression 鍨，

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