Yoshikawa Sakiko, Nodai Etsuo, Habu Manabu, Furuta Norihiko, Fukuda Jinichi, Yamaguchi Kazunori
Division of Orofacial Functions and Orthodontics, Kyushu Dental College, Manazuru, Kitakyushu, Japan.
J Oral Pathol Med. 2008 Jan;37(1):30-7. doi: 10.1111/j.1600-0714.2007.00577.x.
There is limited knowledge relating to the influence of mechanical stress on the temporomandibular joint (TMJ) and the degree of damage this stress can induce in the case of an altered occlusal plane on the extracellular matrix cartilage and chondrocytes. The aim of this study was to examine the histopathological influence of an altered occlusal plane on rabbit TMJ cartilage.
Fifteen male Japanese white rabbits were used in this study. In 12 cases, the upper right and lower left teeth were ground to their cervical level so that the occlusal plane was tilted right side up. Their temporomandibular joints (TMJs) harvested at 3 days, 1, 2 and 4 weeks were analyzed immunocytochemically and immunohistochemically. The terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate biotin nick endlabeling (TUNEL) method was used for immunocytochemical study to detect DNA fragmentation in chondrocytes. An immunohistochemical study was also performed to evaluate the metabolism of type 2 collagen in the extracellular matrix in the TMJ cartilage.
The number of apoptotic cells increased in all experimental animals. More apoptotic cells were observed in the articular eminences than in the condyles. The type 2 collagen-positive area in the condyles was reduced at the beginning but recovered within 4 weeks, and remained small throughout this experimental period in the articular eminences.
These findings suggest that histopathological changes occurred in response to alteration of the occlusal plane. The influence decreased as the occlusal plane recovered in the condyles, but the immunocytochemical and immunohistochemical influence continued in the articular eminences.
关于机械应力对颞下颌关节（TMJ）的影响以及在咬合平面改变时这种应力对细胞外基质软骨和软骨细胞可能造成的损伤程度，目前所知有限。本研究的目的是探讨咬合平面改变对兔颞下颌关节软骨的组织病理学影响。
本研究使用了15只雄性日本白兔。在12只实验兔中，将右上颌和左下颌牙齿磨至颈部水平，使咬合平面向右上方倾斜。在术后3天、1周、2周和4周采集它们的颞下颌关节，进行免疫细胞化学和免疫组织化学分析。免疫细胞化学研究采用末端脱氧核苷酸转移酶介导的脱氧尿苷三磷酸生物素缺口末端标记（TUNEL）法检测软骨细胞中的DNA片段化。同时进行免疫组织化学研究以评估颞下颌关节软骨细胞外基质中Ⅱ型胶原的代谢情况。
所有实验动物的凋亡细胞数量均增加。在关节结节处观察到的凋亡细胞比髁突处更多。髁突处Ⅱ型胶原阳性区域起初减少，但在4周内恢复，而在整个实验期间关节结节处Ⅱ型胶原阳性区域一直较小。
这些发现表明，咬合平面改变会引起组织病理学变化。髁突处因咬合平面恢复，影响减小，但免疫细胞化学和免疫组织化学影响在关节结节处持续存在。
