1. Biomechanics of TMJ
Tongji University

2. Anatomy of TMJ Mandibular condyle Joint surface of temporal bone
Articular disc
TMJ capsule
TMJ ligament
下颌骨髁状突
颞骨关节面
关节盘
关节囊
关节韧带
本图显示为颞骨关节面、下颌骨髁状突、关节盘

3. Anatomy of TMJ Mandibular condyle Joint surface of temporal bone
Articular disc
TMJ capsule
TMJ ligament

4. Muscle tissue related to TMJ
Lateral pterygoid muscle
Upper side & lower side
Function
翼外肌起点：蝶骨大翼的颞下面、颞下嵴
止点：上头-关节盘前缘及部分关节囊；下头-髁突颈部的关节翼肌窝
功能：上头-闭口平衡关节盘、下头-张口、侧方运动
HEAVY LOAD BUT HYPOPLASIA

5. BIOMECHANICS OF TMJ

6. BIOMECHANICS OF TMJ What is biomechanics
Concepts: viscoelastic body; relaxation; creep
Mechanical property of collagen & elastic fiber
生物力学：研究生物与力学有关的问题，试图从力学的角度来了解和解释生命科学，即用力学的原理和方法去研究医学、生理学和其它生物系统的问题。
松弛：即将软骨由原有长度L1迅速拉长到L2，并张紧在L2长度，此时软骨出现张紧力T0，随时间延长张力越来越小，将每一时刻的张力T与T0之比作为时间的函数作出曲线，即是软骨松弛曲线。
蠕变：当软骨受到恒定不变的载荷时，变形将不断增大，最后趋于某一定值。
粘弹性体：
弹性：物体在变形后恢复到变形前的形状和尺寸的能力
粘性：加载时阻滞物体变形、卸载时阻滞物体恢复原有形态的能力。
胶原纤维：韧性材料、抗拉性能优、
弹性纤维：脆性材料、低应力下变形大。抗拉性能差

7. creep relaxation concept 蠕变：当粘弹性体受到恒定不变的载荷时，变形将不断增大，最后趋于某一定值。
解释蠕变时，可举例在吸满水分的高致密海绵上压上一块重物，在受载的初期随时间延长，高致密海绵变形不断增大，最后停在一个定值。
松弛：将粘弹性体由原有长度L1迅速拉长到L2，并张紧在L2长度，此时试件出现张紧力T0，随时间延长张力越来越小，将每一时刻的张力T与T0之比作为时间的函数作出曲线，即是松弛曲线。
解释松弛时，可举例橡皮筋
relaxation

8. FUNCTION MOVEMENT & BIOMECHANICS OF TMJ
Opening and holding
Important balance:
Upper side of lateral pterygoid & upper fiber of bilaminar zone
Movement mechanism of joint disc:
Shape of disc & Pressure in joint

9. FUNCTIONAL MOVEMENT AND BIOMECHANICS OF TMJ
Opening and holding
Normal：
anterior bevel of condyle & intermediate of disc & posterior bevel of joint node — one plane
正常：髁突前斜面、盘中央带、关节结节的后斜面位于同一平面
姿势位：翼外肌轻度收缩
开口：盘被动前移、翼外肌（-）盘后组织被动拉伸
闭口：盘后移 翼外肌（＋＋＋） 盘后组织强力收缩

10. FUNCTIONAL MOVEMENT AND BIOMECHANICS OF TMJ
Chewing process
Balance side
Working side
Balance side
咬硬物时咬合侧关节内压下降，因为
闭合力使下颌骨围绕食物形成支点，引起对侧关节内压增加，咬合侧关节内压突然下降------关节盘前移，厚的后带前移 牙齿穿透食物至ICP位时，工作侧压力上升，盘后移，使中间带重新回到关节窝和髁状突之间，闭合力停止，回到姿势位。
Working side
Movement mechanism of joint disc: Shape of disc & Pressure in joint

11. BIOMECHANICS OF CARTILAGE IN TMJ

12. BIOMECHANICS OF CARTILAGE IN TMJ
Structure of cartilage
H2O
Collagen ：
Protein polysaccharide：
Structural glycoprotein
Cartilage basement
Cartilage cell： ％
蛋白多糖类似于蓄水分子，如只有水和胶原网络则软骨没有外形，蛋白多糖犹如蓄水分子藏于胶原网络之间使软骨具有一定的形态
软骨细胞：毒素敏感，损伤后不再生。代谢低，适宜负荷刺激代谢

13. Articular cartilage－ viscoelastical two phase mixture
BIOMECHANICS OF CARTILAGE IN TMJ
Articular cartilage－ viscoelastical two phase mixture
★ Theory of solid－liquid phase porous viscoelastic body
1。由粘弹性固体基质（胶原、蛋白多糖）和可自由流动的间隙液（水）。
2。软骨受载时、水份挤出，随载荷增大，渗透性下降
3。卸载时，液体回流
Normal
Loading
Unload

14. BIOMECHANICS OF CARTILAGE IN TMJ
Stress cushioning system of cartilage
Shallow level
synovia
Middle level
pression
Cartilage
Deep level
Bone substance of condyle
collagen- Protein polysaccharide –gel
grid structure system
Function of cartilage:
bearing; stress dispersion; stress cushioning; joint lubrication

15. BIOMECHANICS OF CARTILAGE IN TMJ
Lubrication of cartilage
Boundary lubrication
Fluid film lubrication
（weeping~ / pression infiltration ~ ）
Hydroaulic static ~
Hydroaulic motive ~
与滑液、软骨的结构和力学性能、运动状态有关
Joint lubrication related to
synovia & structure and mechanics of cartilage & motion state of cartilage

16. BIOMECHANICS OF DISC AND POSTIOR-DISC TISSUE

17. BIOMECHANICS OF DISC AND POSTIOR-DISC TISSUE
Jiont disc
Stress concentration buffer:
transfer; stress dispersion; short cushioning
Viscoelastic body:
Low permeability &
high compression rigidity
盘表现为波纹状、嵴状突起

18. BIOMECHANICS OF DISC AND POSTIOR-DISC TISSUE
A High compliance fiberous connective tissue
Viscoelastics
Obvious relaxation
High permeability
Low tension strength
High passive deformability
Elastic fiber grid system
Thin and loosen collagen fiber
A; V; N; lymph; fat
结构决定性质
Counterbalance to upper side of lateral pterygoid muscle ×
Disc move forward; multiple perforation in postior area of disc

19. BIOMECHANICS OF CAPSULE AND LIGAMENT OF TMJ

20. BIOMECHANICS OF CAPSULE AND LIGAMENT OF TMJ
Lateral position of TMJ
Post position of TMJ

21. BIOMECHANICS OF CAPSULE AND LIGAMENT OF TMJ
Ligament --- bearing high tension load
Capsule --- adapt to multiway tensile loading; stress dispersion; production and transfer of synovia
assistant
TMJ capsule
Joint ligament
韧带--- 粗大胶原f，抗牵张能力强 ---承载较强的拉伸载荷
囊--- 细小胶原f，组织延展变形性大 ---适应多向拉伸载荷、利于力的分散、关节滑液的产生、运输
Stability of TMJ

22. REMODELING OF TMJ

23. REMODELING OF TMJ Concept
Development of TMJ: 20ys, remodeling in all lifetime
Remodeling
Retrograde remodeling : anterior-lateral incline of condyle & posterior-lateral incline of joint node
Progressive ~：hyperplasia - condyle
Retrograde ~：absorption – condyle; disc; node
组织的改建（remodeling)：TMJ的软硬组织随年龄、功能位置、负荷大小而发生典型的形态改变，这种现象称组织的改建。

24. REMODELING OF HARD TISSUES IN TMJ
Slight periodical load progressive remodeling
2。 Heavy load & long time
remodeling cease
retrograde remodeling destroy of structure and function

25. REMODELING OF SOFT TISSUES IN TMJ
connective tissue zone; proliferative zone; fibrous cartilage zone
Important part: soft tissue on condyle
Remodeling： load
formation of cartilage
Aims: adapt to the needs of function.
proliferation and polarization
TMJ软组织在功能面处最厚
髁突上层软组织是髁突生长变化最活跃的部位，终生不止
改建目的：适应于功能的需要、是咬合治疗、正畸、牙合功能重建的依据，必须渐进性

26. REMODELING OF JOINT CARTILAGE : abrasion and djd
Normal:
Periodical load === swelling pressure
(in collagen- Protein polysaccharide- gel grid system)
Abnormal load system deformation cytoclasis; destroy of collagen Immunoreaction exposure of bone tissue under cartilage stimulate symptom (pain; spasm etc.) fibrosis rigidity of TMJ
生理活动中，关节上承受周期应力，软骨处载荷由胶原－蛋白多糖－水凝胶网架的内部膨胀压平衡。
反复应力导致软骨疲劳性磨损；润滑不佳导致界面磨损。
异常生物力 蛋白多糖－胶原－水凝胶网架构象变形 软骨细胞坏死、胶原断裂 滑膜、滑液及软骨一系列免疫反应 软骨开裂、碎裂，暴露软骨下骨质 刺激滑膜、关节囊炎症、疼痛、痉挛 纤维化 TMJ强直

27. Thanks