Occlusal trauma accelerates attachment loss at the onset of experimental periodontitis in rats
Occlusal trauma accelerates attachment loss at the onset of experimental periodontitis in rats
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DOI：
10.1111/jre.12109
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发表时间：
2014-06-01
影响因子：
3.5
通讯作者：
Hara, Y.
中科院分区：
文献类型：
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作者：
Nakatsu, S.;Yoshinaga, Y.;Hara, Y.
背景与目的咬合创伤是影响牙周炎进展的重要因素，但目前尚不清楚咬合创伤是否影响牙周炎发病时的牙周破坏。我们建立了一种实验性牙周炎模型，既有局部附着丧失，又有牙槽骨吸收。本研究旨在探讨咬合创伤对实验性牙周炎初期牙周破坏，尤其是附着丧失的影响。将48只大鼠随机分为4组，每组10只。创伤(T)组在下颌右第一磨牙的咬合面放置过高的金属丝，造成咬合创伤。炎症(I)组：上颌右第一磨牙腭部牙龈沟局部注射脂多糖诱导牙周炎。创伤+炎症(T+I)组同时诱发创伤和牙周炎。PBS组仅给予磷酸盐缓冲液。另12只未免疫的大鼠(n-(T+I)组)按T+I组的方法处理。术后5d或10d处死大鼠，取上颌第一磨牙及周围组织进行组织病理学观察。组织病理学观察牙槽骨顶附着丧失和破骨细胞的情况。C1qB免疫组织化学染色检测免疫复合体。结果与其他组相比，T+I组的黏附丧失和破骨细胞数量明显增加。T+I组免疫复合体广泛分布，T组、T+I组和n-(T+I)组牙根表面至牙槽骨顶的胶原纤维部分消失。结论炎症合并咬合创伤时，免疫复合体的分布范围较I组非咬合创伤区扩大，牙周炎时牙周炎时的附着丧失增加。咬合创伤对胶原纤维的损伤可能会增加抗原通过组织的通透性，导致免疫复合体形成面积扩大，加速炎症反应。因此，T+I组的牙周组织破坏程度大于I组。
Background and ObjectiveOcclusal trauma is an important factor that influences the progression of periodontitis, but it is unclear whether occlusal trauma influences periodontal destruction at the onset of periodontitis. We established an experimental periodontitis model with both site-specific loss of attachment and alveolar bone resorption. The purpose of the present study was to investigate the effects of occlusal trauma on periodontal destruction, particularly loss of attachment, at the onset of experimental periodontitis.Material and MethodsSixty rats were used in the present study. Forty-eight rats immunized with lipopolysaccharide (LPS) intraperitoneally were divided into four groups. In the trauma (T) group, occlusal trauma was induced by placing an excessively high metal wire in the occlusal surface of the mandibular right first molar. In the inflammation (I) group, periodontal inflammation was induced by topical application of LPS into the palatal gingival sulcus of maxillary right first molars. In the trauma + inflammation (T+I) group, both trauma and periodontal inflammation were simultaneously induced. The PBS group was administered phosphate-buffered saline only. Another 12 nonimmunized rats (the n-(T+I) group) were treated as described for the T+I group. All rats were killed after 5 or 10d, and their maxillary first molars with surrounding tissues were observed histopathologically. Loss of attachment and osteoclasts on the alveolar bone crest were investigated histopathologically. To detect immune complexes, immunohistological staining for C1qB was performed. Collagen fibers were also observed using the picrosirius red-polarization method.ResultsThere were significant increases in loss of attachment and in the number of osteoclasts in the T+I group compared with the other groups. Moreover, widespread distribution of immune complexes was observed in the T + I group, and collagen fibers oriented from the root surface to the alveolar bone crest had partially disappeared in the T, T+I and n-(T+I) groups.ConclusionWhen inflammation was combined with occlusal trauma, immune complexes were confirmed in more expanding areas than in the area of the I group without occlusal trauma, and loss of attachment at the onset of experimental periodontitis was increased. Damage of collagen fibers by occlusal trauma may elevate the permeability of the antigen through the tissue and result in expansion of the area of immune-complex formation and accelerating inflammatory reaction. The periodontal tissue destruction was thus greater in the T+I group than in the I group.