组织工程化人形下颌骨髁状突的实验研究

目的　评价采用组织工程技术构建人下颌骨髁状突软骨复合组织的可行性。方法　以可降解生物材料聚羟基乙酸 (polyglycolicacid ,PGA) /聚乳酸 (polylacticacid ,PLA)预制人下颌骨髁状突模型 ,体外培养扩增牛骨膜成骨细胞和牛关节表面软骨。实验分 3组 :第 1组 ,模型内仅注入 1.5 %藻酸钙和 30 %氧化乙丙烯 ;第 2组 ,模型内分别注入成骨细胞和软骨细胞悬液 ,浓度为 5× 10 7/ml;第 3组 ,模型内接种成骨细胞藻酸钙悬液 ,同时在模型关节表面涂敷软骨细胞 PluronicF12 7悬液 ,浓度为 5× 10 7/ml。分别植入裸鼠皮下 ,12周后取材 ,作大体和组织学观察。结果　第 1组无骨和软骨形成 ,模型支架明显缩小 ,形态不规则 ;第 2组仅留残缺不全的组织结构 ,标本体积缩小变形 ;第 3组形态结构与原植入模型支架相同 ,组织学观察有骨和软骨组织结构 ,两者界面连接有序 ,骨组织内有大量新生骨板。结论　以人工合成生物材料预制人下颌骨髁状突支架 ,采用组织工程技术 ,可以在裸鼠体内构建具有骨软骨复合结构的正常形态的人形下颌骨髁状突 ,从而为进一步临床应用提供了理论依据     

颞下颌关节盘摘除对骨膜移植修复髁突软骨缺损的影响

目的 :颞下颌关节紊乱综合征器质性病变的病例中 ,常可见关节盘及髁状突软骨严重破坏的情况 ,因而不得不行关节盘摘除术、髁状突高位切除术。为了寻求在关节盘摘除术后用骨膜移植修复髁状突软骨缺损的可行性 ,本实验将家兔的一侧关节的关节盘摘除后并造成 4mm× 3mm大小的髁状突软骨缺损区 ,用自体游离骨膜移植于软骨缺损区。术后 16周处死动物 ,对缺损区的新生软骨及邻近原正常软骨组织进行大体和组织学观察 ,并与未摘除关节盘组 (组Ⅱ )相对照。结果显示 :在关节盘摘除后 ,行游离骨膜移植修复髁状突软骨缺损效果较差 ,且易导致邻近原正常软骨的变性性改变     

单侧后牙反患者髁状突及下颌升支对称性的螺旋CT研究

目的:探讨单侧后牙反成年患者髁状突及下颌升支的对称性。方法:对22例单侧后牙反患者进行螺旋CT扫描、多层面重建和相关参数测量,并进行统计分析。结果:双侧髁突内、外突点的距离,髁突内倾角及下颌角点的距离有显著差异,但髁突左右径、髁状突最大横截面积、下颌支高度及下颌支冠状位最大面积的差异无统计学意义。结论:单侧后牙反患者左右侧髁状突及下颌支的位置不对称,但髁突及下颌升支大小无显著差异。     

下颌定位仪指导下颌稳定性(牙合)垫调磨对髁突运动中心位置的影响

目的：观察[牙合]垫对髁突运动中心位置的影响,并探讨下颌定位技术测定髁突运动中心电子位置（ele-ctronic position analysis,EPA）指导[牙合]垫调磨的方法。方法：从3158例颞下颌关节紊乱病患者中,选择46例（92侧关节）有下颌绞锁运动症状的颞下颌关节紊乱病患者,接受下颌稳定垫治疗;常规调磨后,为患者戴入合垫,再用超声三维下颌定位仪（3D-ultrasonic navigator）进行髁突运动中心电子位置及下颌运动功能分析,观察常规方法调磨后垫治疗对髁突运动中心的影响;对引起双侧髁突运动中心不均衡位移的病例,则根据EPA的测试,对[牙合]垫进行修正性调磨。结果：常规调磨后,67.4%（31/46）的患者双侧髁突运动中心在矢状位的位移距离明显不均衡;63%（29/46）的患者双侧髁突运动中心的位移方向不一致;而根据EPA检测修正性调磨后,91.3%（42/46）的患者双侧髁突运动中心的位移方向达到了一致。常规调磨与修正性调磨对[牙合]垫引起髁突运动中心位移时双侧的均衡性与方向一致性上的差异均具有统计学意义。结论：稳定[牙合]垫治疗颞下颌关节紊乱病过程中,超声三维下颌定位仪中的EPA检测指导下进行修正性调磨可以提高双侧髁突运动中心的位移距离和方向的一致性。     

下颌第二磨牙咬合接触变化对颞下颌关节应力分布的影响

目的 用力学研究方法结合有限元技术分析下颌第二磨牙咬合接触部位改变时，相同压强咬合载荷条件下颞下颌关节应力的变化。方法 在包括左侧下颌第二磨牙在内的颞下颌关节三维有限元模型上，设计下颌第二磨牙牙尖交错He(ICO)、远中和颊侧3种加载部位的工况，通过有限元运算探讨双侧髁突应力分布的变化规律。结果 由于咬合加载部位的牙面承载形态不同，在双侧髁突上产生了不同的应力效应，其变化包括应力性质和应力分布特点等方面，远中加载和颊侧加载时对侧髁突的Von Mises应力最大值由ICO加载时的51．51MPa分别增加到72．15MPa和69．57MPa。结论 与单侧下颌第二磨牙承载部位变化相关的咬合力方向变化，可使同一力值的咬合力产生不同的双侧髁突应力效应。     

Condylar response to functional therapy with Twin-Block as shown by cone-beam computed tomography

Objective:To evaluate the condylar changes through cone-beam computed tomography (CBCT) images in patients treated with Twin-Block functional appliance.Materials and Methods:In this retrospective study, CBCT images of 30 patients who were treated with the Twin-Block appliance were used. Mandible was segmented and pretreatment and posttreatment (T0 and T1) condylar volume was compared. The angle between sella-nasion-Point A (SNA), angle between sella-nasion-Point B (SNB), angle between Point A-nasion-Point B (ANB), midfacial length (Co-A), mandibular length (Co-Gn), and the distances from right condylion to left condylion (Co_R-Co_L) were also measured on three-dimensional images. Differences were analyzed with Wilcoxon signed rank tests, and Mann-Whitney U-tests were used to compare the scores of male and female participants. Significance was set at P < .05.Results:In this study, a decrease in SNA and ANB (P < .05 and P < .01, respectively) and an increase in SNB (P < .01) were found. Additionally, Co_R-Co_L, Co-Gn, and condylar volume increased at both the left and right sides (P < .01). However, increase at Co-A was not statistically significant (P > .05). Comparison of differences by sex was not statistically significant for all measurements (P > .05).Conclusion:Twin-Block appliance increases condylar volume, mandibular length, and intercondylar distance by stimulating growth of condyle in an upward and backward direction.     

A CBCT study on positional change in mandibular condyle according to metallic anchorage methods in skeletal class III patients after orthognatic surgery

PurposeThis study was to evaluate the postoperative stability of the mandibular condyle according to the number of screws in the proximal segment using cone beam computed tomography (CBCT).Patients and methodsThirty patients diagnosed with skeletal class III malocclusion and underwent sagittal split ramus osteotomy (SSRO) were enrolled in this study. In Group A, 4 screws and a 4-hole miniplate were used for the internal fixation of an osteotomy and 3 screws, only 1 screw in the proximal segment, and a 4-hole miniplate were used in Group B. We digitally measured anteroposterior, supero-inferior, and mediolateral positions and angles of the long axis of the mediolateral poles in CBCT scans pre-operatively, within 1 week postoperatively and 3, 6 months after surgery.ResultsThe condylar head angle in the axial plane showed consistent and significant changes. The condylar head angle in the coronal plane decreased in both groups, which shows that condylar heads bent inward. In the axial plane, Group A showed statistically significant differences while Group B did not in early stage (T0–T1–T2). The change in distance between condylar heads shows that these have moved outward in both groups.ConclusionThe results show that a fixation method using 3 screws with a 4-hole miniplate did seemed preferable and may give some flexibility for condylar heads to be positioned in physiologic position during postoperative phase.     

生长期兔髁突软骨细胞体外培养方法及其生物学特性研究

目的：建立髁突软骨细胞体外培养模型,研究其生物学特性。方法：分离4周龄健康新西兰大白兔双侧髁突软骨,采用胰酶和胶原酶联合消化方法收集4h和12h2个时间点的髁突软骨细胞,连续体外培养并传代至PIO。使用倒置显微镜观察细胞形态;采用甲苯胺蓝、阿利新蓝和免疫细胞化学染色对髁突软骨细胞进行鉴定：利用细胞计数绘制细胞生长曲线;通过Western免疫印迹分析细胞Ⅱ型胶原、X型胶原和SOX9在蛋白水平的表达情况。采用SPSS13．0软件包对WeS[eFn印迹条带灰度值进行统计学分析。结果：兔髁突软骨细胞体积较大,呈纺锤形或多角形．铺路石样排列,细胞爬片染色结果为阳性。随着细胞传代“成纤维样”细胞比例逐渐加重．P2代之前的细胞形态差异较小。细胞生长曲线显示,兔髁突软骨细胞的体外培养符合经典的S形生长曲线。Western印迹结果表明,4h和12h所收髁突软骨细胞Ⅱ型胶原、X型胶原和SOX9表达无显著差异。结论：使用本方法培养兔髁突软骨细胞简单有效。髁突软骨细胞体外培养存在去分化现象,但P2代以内的髁突软骨细胞生物学特性相对稳定．适合用于后期实验研究,P3代以后的髁突软骨细胞逐渐丧失原有细胞的特性。     

The effects of elevated fibroblast growth factor 23 on mandibular growth in rats

ObjectiveThe aim of this study is to elucidate the local effects of fibroblast growth factor 23 (FGF23) in on mandibular condylar growth in growing rats.DesignGrowing Sprague–Dawley rats received intra-temporomandibular joint injections of phosphate buffer solution (PBS), adenovirus-mediated green fluorescent protein (Ad-GFP) or adenovirus-mediated fibroblast growth factor 23 (Ad-FGF23), which were marked as groups A, B, and C, respectively. In vitro, we treated rat mandibular cartilage chondrocytes with PBS, Ad-GFP, and Ad-FGF23.ResultsThe mandibular condyles in group C grew smaller sizes than those in the other control groups due to significant differences among the experimental and control groups with the value of C–D, Q–R (P ≤ 0.05), accompanied by diminished bone mass of sub-cartilage condyles via micro CT analysis. Histologically, the length of the hypertrophic zone was diminished and was associated with decreasing chondrocyte proliferation in group C. Quantitative real-time PCR indicated significant decreases in the expression of chondrogenesis marker genes, including Type X collagen (Col X) and SRY-type box 9 (Sox 9). Moreover, elevated Ad-FGF23 suppressed chondrocyte proliferation and the expression of the chondrogenic differentiation markers Col X and Sox 9 of in vitro.ConclusionsLocal injection of FGF23 suppressed the development and decreased the bone mass of condyles through the decreasing the formation of condylar cartilage, specifically by regulating condylar cartilage cell viability and chondrogenesis expression.     

减小后牙▉平面倾斜度对安氏Ⅱ类高角畸形髁突位置影响的研究

目的: 研究在安氏Ⅱ类高角畸形正畸治疗中,减小后牙平面倾斜度对髁突位置的影响。方法: 15例安氏Ⅱ类高角畸形患者,年龄15~30岁。治疗前ANB>5°,下颌平面角FH-MP>32°,磨牙关系为双侧远中关系。常规排齐整平及适当扩弓后,利用多曲唇弓导下颌向前,并使后牙平面平坦化。利用锥形束CT（cone-beam CT,CBCT）测量治疗前、后颞下颌关节前、上、后间隙及后牙平面的改变情况。采用SPSS19软件包对变化量进行t检验;并利用相关性分析,进一步探讨髁突位置改变量与后牙平面倾斜度减小量之间的相关性。结果: 所有患者磨牙尖牙关系均调整到中性,侧貌改善明显,髁突后间隙平均增加(0.88±0.17)mm,变化有统计学意义(P<0.001);髁突上间隙平均增加(0.45±0.20)mm,变化也具有统计学意义(P<0.05)。后牙平面变平坦,POP-SN及POP-FH平均减小3.59°±2.31°及2.31°±3.62°,变化具有统计学意义(P<0.001)。髁突前间隙变化量无统计学意义,髁突位置改变量与后牙平面倾角的变化量之间无显著相关性。结论: 在安氏Ⅱ类高角畸形患者的正畸治疗中,通过正畸减小后牙平面倾斜度,可使髁突的位置发生适当的前下改变,有利于关节症状的改善。