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Temporo Mandibular joint (TMJ) importance in orthodontic treatment /certified fixed orthodontic courses by Indian dental academy

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  • Head fold begins to form,floor of the stomato is the buccopharyngeal mem,head represents the bulging of the brain while the pericardium occupies the future thorax,neckis formed by the elongation b/w this two,mainly by the appearance of a series of mesodermal thickenings in the cranial most part of the fore gut –pharyngeal archs.
  • Coronal section through cranial part of foregut before & after formation of the pharyngeal arches .embryo showing limb buds
  • Structures present in the arch
  • derivatives
  • Before formation of frontonasal process & after formation. Dev of face,fromation of max &man process.mandibular arch forms the lateral wall of the stomatodium,gives a bud like st.max process from its dorsal end,grows ventromedially.grows to meet at the midline forming the lower margin of the stomatodium,giving rise to the lower lip &mand.
  • Blastema- a group of cells giving rise to a new organ or part either in normal dev or in regeneration.they are situated at a relatively large distance. The first evolves to contribute to the formation of condylar cartilage,the aponeurosis of the external pterygoid muscle, the disc,& the capsular elements of the lower joint . The second develops into the articular st of the upper level.
  • Pterygoid fovea- attachment of the inf. Head of the lateral pterygoid & is situated on the ant part of the neck below the articular surface.
  • The process involves mineralization of the cartilage matrix & subsequent degeneration of chondrocytes.osteo blasts deposit woven bone around the template of calcified cartilage –mature bone
  • Tmj lat view
  • Chondrotin sulphate –presence suggest that the disc is subjected to compressive loads.
  • Cross bite,deepbite.trauma,emotional stress,systemic condition,bruxism
  • Mild physical therapy,flat appliance,4-6weeks
  • 5degr of change can alter the condyle position
  • Hemangioma

Temporo Mandibular joint (TMJ) importance in orthodontic treatment  /certified fixed orthodontic courses by Indian dental academy Temporo Mandibular joint (TMJ) importance in orthodontic treatment /certified fixed orthodontic courses by Indian dental academy Presentation Transcript

  • INDIAN DENTAL ACADEMYLeader in Continuing Dental Education www.indiandentalacademy.co
  • •INTRODUCTION •CLASSIFICATION OF JOINTS •EVOLUTION OF TMJ & JAWS •DEVELOPMENT OF TMJ •MUSCLES OF MASTICATION •TMJ ANATOMY •HISTOLOGY •BIOMECHANICS OF TMJ •EXAMINATION OF TMJ •DIAGNOSTIC IMAGING •TMD •CONCLUSION •REFERANCESwww.indiandentalacademy.co
  • INTRODUCTION www.indiandentalacademy.co
  • Why study TMJ as an orthodontist ?The TMJ influences the function, esthetics, &structural harmony of the teeth, dentition, faceand thus a person in total.Therefore an understanding of the anatomy ,physiology, biomechanics etc., of the masticatorysystem is very www.indiandentalacademy.co much necessary.
  • The masticatory system or the somatognathicsystem consists of the skull bones, mandible,hyoid, clavicle, sternum; the masticatorymuscles,& ligaments; the dentoalveolar complex;the vascular, neural & lymphatics and the TMJ.The masticatory system is responsible forCHEWING, DEGLUTATION, SPEECH, etc………… www.indiandentalacademy.co
  • Classification of Joints1.SYNARTHROSIS:(i) FIBROUS JOINTS A: SUTURES (collagenous sutural ligament) B: SYNDESMOSES (collagenous ligament + elastic fibrous tissue) C: GOMPHOSES (complex fibrous & cellular periodontium)(ii) CARTILIGENOUS JOINT A: SYNCHONDROSIS (hyaline cartilage) B.SYMPHYSES (hyaline cartilage+ fibrocartilagenous disk)(iii) SYNOSTOSES (rigid bony unions)2. DIARTHROSES:SYNOVIAL JOINT (Synovial fluid present between articulating surfaces) www.indiandentalacademy.co
  • Classification of Joints •FIBROUS •CARTILAGENOUS •PRIMARY •SECONDARY •SYNOVIAL www.indiandentalacademy.co
  • Temperomandibular joint“Nothing is more fundamental in treating patientsthan knowing the anatomy.” - Okeson Most human bones are connected to each other byJOINTS or ARTICULATIONS. Some of them beingmobile while being immobile. In the mobile joints the surfaces are covered bycartilage & fibrous tissue forming a capsule.the innerlining cells secrete SYNOVIAL fluid that allowsfreedom for the joint to move. www.indiandentalacademy.co
  • •TEMPEROMANDIBULAR JOINT IS A COMPOUND,BICONDYLAR, GINGLIMO-ARTHROIDAL, ELIPSOIDAL,SYNOVIAL JOINT.•IT IS A WEIGHT BEARING JOINT. IT BEARSABOUT 500N OF FORCE.•THE TMJ IS LOADED MORE IN THE NON WORKINGCONDITION THAN IN WORKING SIDE.•TMJ IS ONE OF THE MOST COMPLICATED JOINTSIN THE BOBY AND IT IS FORMED BY THEARTICULATION OF THE MANDIBLE TO THECRANIUM.•THE MANDIBULAR CONDYLAR HEADS FITS INTOTHE GLENOID FOSSAE OF THE SQUAMOUS PART OFTHE TEMPORAL BONE INTERPOSED BY ANARTICULAR DISC IN BETWEEN. www.indiandentalacademy.co
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  • An Amphibian jaw-articulation b/w the terminalportion of Meckels cartilage& the palatoquadrate bar.Teeth are confined to thedentary boneA Reptile jaw- dentary is ofincreased size Fossil Mammal like Reptile- enlarged dentary & has coronoid process Mammals- Articulation of dentary with the temporal bone & www.indiandentalacademy.co inner ear. constitutes part of
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  • Embryology – Cranial most part –enlarges Two big bulging in the ventral aspect of the embryo. Depression - Stomatodeum Neural groove – 21st day Closure of neural tube – 23rd daywww.indiandentalacademy.co
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  • 1st arch – Mandibular arch2nd arch – Hyoid arch3rd arch4th arch No Names6th arch5th arch – Disappears soon after formation. www.indiandentalacademy.co
  • 1st – Meckels cartilage , incus & malleus , also ant. lig. of malleus & Sphenomandibular lig 2nd - Stapes , Styloid process , Stylohyoid lig , Smaller cornu of hyoid , Superior part of body of hyoid. 3rd – Greater cornu of hyoid bone , lower part of the body of hyoid bone. 4th & 6th – Cartilages of larynx.www.indiandentalacademy.co
  • 4th to 28 weeks www.indiandentalacademy.co
  • Development of TMJ → Acc to Baume, temporomandibular articulation originate from two different blastema. The Condylar blastema & the Temporal blastema. Condylar blastema –(primodium of the mandible) - condylar cartilage - the aponeurosis of the external pterygoid muscle - the disc - the capsular elements of the lower joint. www.indiandentalacademy.co
  • Temporal Blastema – - Articular structures of the upper levelCondylar blastema forms at the distal end ofthe primordium of the mandible.The mandible begins to ossify – 7th week offetal life / 19mm stage of fetal development.22mm stage / 8th week – bone laid down in aplatelike form lateral to Meckels cartilage. www.indiandentalacademy.co
  • week IU Meckels cartilage extends from the Cartilaginous otic capsule to the midline symphysis bone of the mandible is forming in the membrane Tongue Meckels cartilage www.indiandentalacademy.co
  • Phylogenetically , the developing middle ear inprimates & especially the humans was theinitial jaw joint of the vertebratesIn the middle ear region that the malleus &probably the incus develop as posteriorextensions of Meckels cartilage.The intermediate portion of Meckels cartilagedisappears, but its sheath remains to persistin the form of anterior malleolar ligament & thesphenomandibular lig. www.indiandentalacademy.co
  • A -relationship b/w A -Anterior malleolar lig. mandible & middle ear. B -MalleusB -reference to C - Incus Meckels cartilage. www.indiandentalacademy.co
  • 24mm stage embryo, the pterygoid & massetermuscles have differentiated.At the superior border of the external pterygoidmuscle & just below to the masseter muscle, alayer / bulk of mesenchyme tissue which is theanalogue of articular disc. 28mm stage the middle ear ossicles are fully formed in true cartilage & malleus is continuous with the Meckels cartilage.-Articular disc & external pterygoid tendons are attached to the malleus. www.indiandentalacademy.co
  • 11th week – condylar cartilage becomesevident, located at the upper end of theposterior border of developing mandible.30mm stage embryo – articular surface facesdirectly lateral, it is parallel to the articulardisc as well as to the articular surface of thezygomatic process of the temporal bone.50mm stage – condylar cartilage shapes thearticulating surface of the condyle in ahemisphere. www.indiandentalacademy.co
  • - Articular disc has flattened & the plane of the articular surfaces has undertaken a shift of 450- 55mm stage – condylar head produces an osseous head which matures into condylar cartilage by 65mm stage – Baume.- 85mm stage – ossification of the cartilage begins, growth center of the mandible. - joint cavity formation is evident as the loose connective tissue on either side of the future articular disc becomes less dense. www.indiandentalacademy.co
  • Inferior portion of the joint cavity takes theshape of a distinct cleft.13th week – the lower joint cavity is wellformed around the superior surface of thecondyle, so as the upper part.15th week – vascular mesenchyme of thecondylar cartilage can be seen breakingdown. - both joint cavities are formed. www.indiandentalacademy.co
  • At 155mm stage – differentiation continuesanteriorly to arrive at a point of fullarticulation.190mm stage – all the elements of the jointare fully formed.Baume, full differentiation of all articularelements by 4th fetal month. www.indiandentalacademy.co
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  • 14 weeks of Human Fetus Parietal boneOccipital Frontal boneSquamousPartSecondary Secondarycondylar coronoid cartilageCartilageRamus Maxilla Body of mandible www.indiandentalacademy.co
  • 8th – 10th weeks IU – proliferation & histodifferentiation takesplace & condyle assumes its mature morphogenic pattern.Also 1st evidence of temporal bone12th – 14th week IU – formation of articular disc22nd week IU – both articular eminence & the glenoid fossaare well formedMeckels cartilage plays no role in actual dev of TMJ, acts asa frame work / scaffold for the dev mandible.Ramus formed of membranous bone & endochondral boneformation at the head of the condyle.Early attachment of muscles of mastication – 8th week.Attachment of external pterygoid – 13th week.Masseter muscle attachment – 14th week. www.indiandentalacademy.co
  • Joint Innervation –Kitamura; - branches of Auriculotemporal nerve,masseter nerve, & the posterior deep temporal nerveBranches of Mandibular portion of TrigeminalN.4th fetal month – nerve fibers may beobserved in the articular capsule www.indiandentalacademy.co
  • 5th month – appear to reach the disc.6th month – widest distribution over thecondyle & within the disc.Localization & distribution of nerve fibers atjoint margins.Nerve fibers in capsule innervate the synovialmembrane of the joint as well. www.indiandentalacademy.co
  • Du Brul;- the key relationship b/w jaw & ear dysfunction lies inthe embryological development of the neuralpatterns of the TMJ.- demonstrated that the nerve to the internalpterygoid muscle also sends a branch to tensortympani muscle (moves the malleus)He states unequivocally that, “ Herein lies the key tothe relationship b/w jaw & ear dysfunctionssometimes plaguing modern man along with thedeteriorating of other parts of jaw & dentalapparatus” www.indiandentalacademy.co
  • A – Mandible at birthB – At 6 years Lateral ViewC – In an Adult www.indiandentalacademy.co
  • Occulsal View A- At birth B- At 6 yrs C- Adultwww.indiandentalacademy.co
  • MUSCLES OF MASTICATION - MASSETER - TEMPORALIS - LATERAL PTERYGOID -MEDIAL PTERYGOID www.indiandentalacademy.co
  • INTRODUCTION Moves the mandible during chewing and speech. These are SKELETAL, VOLUNTARY muscles. Consists of - Masseter - Temporalis - Lateral Pterygoid - Medial Pterygoid - Buccinator (accessory /5th muscle)- Ant. belly of digastric, geniohyoid,mylohyoid, www.indiandentalacademy.co
  • MUSCLES OF MASTICATION www.indiandentalacademy.co
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  • DEVELOPMENTIt develops from the mesoderm of the 1st PHARANGIAL ARCH. www.indiandentalacademy.co
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  • MASSETERQuadrilateral muscle that covers lateral surfaceof the mandible.Has 3 layers: superficial, middle & deep.Multipinnate arrangement of fibers www.indiandentalacademy.co
  • LAYERS ORIGIN FIBERS INSERTIONSUPERFICIAL: ANT.2/3 OF LOWER - PASS LOWER PART OF BORDER DOWNWARDS & LATERAL ZYGOMATIC ARCH & BACKWARDS AT SURFACE OF ZYG. PROCESS OF 45º MAND. MAXLLLA.MIDDLE: ANT. 2/3 OF DEEP - VERTICALLY & MIDDLE PART OF  SURFACE & POST. DOWNWARDS. RAMUS 1/3 OF LOWER   BORDER OF ZYG. ARCH.  DEEP: DEEP SURFACE OF -   LAYERS ARE 3 UPPER PART OF  ZYG. ARCH SEPERATED BY AN RAMUS AND ARTERY & A NERVE CORONOID www.indiandentalacademy.co
  • TEMPORALIS FAN shaped muscle.Fills the Temporal Fossa.MUSCLE ORIGIN FIBERS INSERTIONTEMPORALIS TEMPORAL CONVERGE & -MARGIN & DEEP BONE AND PASSES SURFACE OF FASCIA THROUGH GAP CORONOID DEEP TO ZYG. - ANT. BORDERS ARCH OF RAMUS OF MAND. www.indiandentalacademy.co
  • LATERAL & MEDIALPTERYGOIDLATERAL PTERYGOID:It is a short & conical muscle.Has upper & lower head.MEDIAL PTERYGOID:Quadrilateral muscleHas superficial & deep head www.indiandentalacademy.co
  • LATERAL ORIGIN FIBERS INSERTIONPTERYGOIDUPPER (SMALL) FROM RUN BACKWARDS PTERYGOID FOVEA INFRATEMPORAL & LATERALLY. (CONDYLAR NECK) SURFACE & CREST OF CONVERGE FOR G.WING OF SPHENOID INSERTION    LOWER LATERAL SURFACE OF ANT. MARGIN OF(LARGER) LATERAL PTERYGOID ARTICULAR DISC & PLATE CAPSULE OF TMJ.MEDIAL ORIGIN FIBERS INSERTIONPTERYGOIDSUPERFICIAL TUBEROSITY OF DOWNWARDS, MEDIAL SURFACE OF(SMALL) MAXILLA & ADJOINING BACKWARDS & ANGLE & RAMUS OF BONE LATERALLY MANDIBLEDEEP MEDIAL SURFACE OF   BELOW & BEHIND(LARGE) LATERAL PTERYGOID   MAND. FORAMEN & PLATE & ADJ.   MYLOHYOID GROOVE PROCESS OF   PALATINE BONE   www.indiandentalacademy.co  
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  • SUPPLIES: MUSCLE ARTERY VEIN NERVEMASSETER MASSETRIC.A. RESPECTIVE VEIN MASSETRIC NR. (II PART OF (BR.OF ANT. DIV.OF MAXILLARY A.) MAND.NR)TEMPORALIS SUP. TEMPORAL A. DEEP TEMPORAL PTERYGOID (BR.OF ANT. VENOUS PLEXUS DIV.OFMAND.NR) LATERAL LAT. PTERYGOID. LAT. PTERYGOIDPTERYGOID (II PART OF MAXILLARY VEIN (BR.OF ANT. DIV.OF MAXILLARY A.) MAND.NR) MEDIAL MED. PTERGOID. MED. PTERYGOIDPTERYGOID (II PART OF RETROMANDIBULAR (BR. OF MAIN MAXILLARY A.) VEIN TRUNK OF MAND. www.indiandentalacademy.co NR.)
  • ELEVATION TEMPORALIS MASSETER MEDIAL PTERYGOIDRETRACTION PROTRACTION DIGASTRIC GENIOHYOID LATERAL PTERYGOID MYLOHYOID DEPRESSION www.indiandentalacademy.co
  • Temporomandibular joint proper www.indiandentalacademy.co
  • The three major skeletal components thatmake up the masticatory system :MaxillaMandibleTemporal bone www.indiandentalacademy.co
  • Temporalbone A- mandibular fossa B- external acoustic meatus C- articular eminence D- zygomatic process E- tympanic plate F- petrosquamous fissure www.indiandentalacademy.co
  • A- body A- genial spine (tubercles)B- ramus B- internal oblique ridgeC- incisive fossa C- attach. area for medial pterygoidD- mental foramina D- temporal crestE- angle E- retromolar triangleF- external oblique line F- mandibular foraminaG- coronoid process G- lingulaH- condyle www.indiandentalacademy.co groove H- mylohyoid
  • Condyle LP- lateralpole MP- medialpole pterygoid fovea www.indiandentalacademy.co
  • 1450line drawn through the centers of the poles ofthe condyles, usually extends medially &posteriorly towards the anterior border of theforamen magnum. www.indiandentalacademy.co
  • mm The articulating surface of the condyle extends both anteriorly & posteriorly to the mostsuperior aspect of the condyle. Posterior articulating surface is greater than anterior surface & is quite convex www.indiandentalacademy.co
  • HISTOLOGY OF TMJ- Histologically the appearance varies with age, due to presence of secondary cartilage.- This cartilage appears about 10th month IU & remains as a zone of proliferating cartilage until about the later half of the second decade of life.- The condyle of the young child is not lined by a distinct layer of compact bone as is that of the adult. www.indiandentalacademy.co
  • A- fibrous articular layerB- cell rich proliferative layerC- hypertrophic condrocytes of the secondary cartilageD- woven bone being deposited aroundE- a template of calcified cartilageF- marrow space -multinucleated osteoclast - osteoblast layer depositing bone on calcified cartilage. www.indiandentalacademy.co
  • A – head of adult condyle A – collagen fibers at the centreB – lower part of intraarticular B – regularly aligned at periphery disc C – larger marrow spaces & lack of a layer of compact boneC – fibrous articular layer D – articular surface of mandibular(collagen are crimmped) fossa www.indiandentalacademy.co
  • Histology of articular surface-A – condyle headB – fibrous articular surface zoneC – cellular rich zoneD – fibrocartilagenous zoneE – zone of calcified cartilageF – lower joint spaceG – intra articular space www.indiandentalacademy.co
  • Articular disc- Composed of dense fibrous connective tissue- Extreme periphery of the disc , is innervated Sagittal plane –AB- anterior borderPB- posterior borderIZ- intermediate zone www.indiandentalacademy.co
  • Anterior view –the disc is slightthicker medially thanlaterally.LP- lateral poleMP- medial pole www.indiandentalacademy.co
  • -Sagittal section of the intra- - Adult intra articular disc articular disc of a neonate - shows sparse distribution-presence of numerous of cells fibroblasts. - rounded cartilage -like cells www.indiandentalacademy.co
  • ACL- anterior capsular lig. AS- articular surfaceIC- inferior joint cavity ILP- inferior lateral pterygoid musclesIRL- inferior retrodiscal lamina RT- retrodiscal tissuesSC- superior joint cavity SLP- superior lateral pterygoid musclesSRL- superior retrodiscal lamina ELASTIC COLLAGENOUS www.indiandentalacademy.co
  • The articular disc is attached to the capsular lig. ,notonly anteriorly & posteriorly, but also medially &laterally; this attachment divides the joint into ; a) the upper cavity [superior cavity] b) the lower cavity [inferior cavity]Upper is bordered by, the mandibular fossa & thesuperior surface of the disc.Lower is by, the mandibular condyle & the inferiorsurface of the disc. www.indiandentalacademy.co
  • Specialized endothelial cells forms a synovial lining surrounding the internal surface of the cavities. This lining along with a specialized synovial fringe located at the anterior border of the retrodiscal tissues, produce synovial fluid.Synovial Fluid –i) metabolic requirements to the non-vascular articular surfaces of the joint.ii) lubrication during function, reducing friction. www.indiandentalacademy.co
  • Lubrication –i) Boundary lubricationii) Weeping lubrication Boundary lubrication –-when the joint moves, the synovial fluid is forced from one area of the cavity to another.-prevents friction & is the primary mechanism of joint lub. Weeping lubrication –-the ability of the articular surfaces to absorb a small amount of fluid.-forces during function drive a small amount of fluid in & out of the articular tissues, helps in metabolic exchange. www.indiandentalacademy.co
  • Compressive forces - release fluid & preventssticking of articular tissues.Weeping eliminates friction in compressed but notmoving joint.But prolonged compressive forces will exhausts thissupply leading to deleterious effects. www.indiandentalacademy.co
  • Crimping of collagen fibers in the intra articular disc is indicative of tensional loads.About 2/3rd s of the glycosaminoglycan is chondroitin sulphate & 1/3rd is dermatan sulphate, traces of hyaluronan & heparin sulphate. www.indiandentalacademy.co
  • Innervation of TMJ –- The trigeminal nerve , that provides both motor & sensory innervation to the muscles that control it.- Afferent innervation – branches of the mandibular nerve.- Also by auriculo-temporal nerve as it leaves the mandibular nerve behind the joint & ascends laterally & superior to wrap around the posterior region of the joint.- Additional nerves – temporal & masseteric . www.indiandentalacademy.co
  • RUFFINI Posture Dynamic & (proprioception) static balance (capsule)PACINI Dynamic Movement (mechanoreception) accelerator (capsule)GOLGI Static Protection (mechanoreception) (ligament)FREE Pain Protection (nociception) (joint) www.indiandentalacademy.co
  • Vascularization –- predominantly ; i) from posterior- superficial temporal artery ii) from anterior- middle meningeal artery iii) from inferior- internal maxillary artery iv) others ; - the deep auricular - anterior tympanic - ascending pharyngeal arteries- condyle, receives through its marrow spaces by “feeder vessels” from inferior alveolar artery. www.indiandentalacademy.co
  • LIGAMENTSMade up of collagenous connective tissues havingparticular lengths & they do not stretch.Act as passive restraining devices to limit & restrictborder movements.The three functional ligs ; i) the collateral lig ii) the capsular lig www.indiandentalacademy.co iii) the temporomandibular lig
  • AD- Articular discCL- Capsular ligamentIC- Inferior joint cavitySC- Superior joint cavityLDL- Lateral discal ligMDL- Medial discal lig www.indiandentalacademy.co
  • Collateral (discal ligaments) :- Attaches the medial & lateral borders of the articular disc to the poles of the condyles.- Divides the joint mediolaterally into the superior & inferior cavities.- True ligs , do not stretch & restricts movement of the disc away from condyle.- Responsible for hinging movement of the TMJ.- Have both vascular as well as innervation , providing information regarding joint position & movement.- Strain on these ligs produces pain. www.indiandentalacademy.co
  • Capsular ligament- surrounds & encompasses the entire TMJ.- superiorly to the temporal bone along the borders of the articular surfaces of the mandibular fossa & articular eminence.- inferiorly – neck of the condyle- resist any medial, lateral / inferior forces that tend to separate / dislocate the articular surfaces.- helps to retain synovial fluid & provides proprioceptive feedback. www.indiandentalacademy.co
  • Temporomandibular (Lateral) ligament IHP-Inner horizontal portion OOP-Outer oblique portionOblique portion – resists excessive dropping of the condyle- normal opening of the mouth.- wider mouth opening- the condyle moves downwards & forward across the articular eminence.- unique limited www.indiandentalacademy.co rotational opening is found only in
  • - in erect postural position & with a vertically placed vertical column, continued rotational opening movement would cause the mandible to impinge on the vital sub-mandibular & retro-mandibular structures of the neck.Inner horizontal portion ; - limits the posterior movement of the condyle & disc. - protects the retrodiscal tissues from trauma. - also protects the lateral pterygoid muscle from over- lengthening / extension - trauma to the mandible – neck of the condyle will fracture before the retrodiscal tissues are severed / before the condyle enters the middle cranial fossa. www.indiandentalacademy.co
  • Accessory ligs ; i) the sphenomandibular lig ii) the stylomandibular lig iii) the pterygomandibular raphe iv) the retinacular lig www.indiandentalacademy.co
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  • BIOMECHANICS OF TMJ – Can be divided into two system:1) One joint system; Tissues surrounding the inferior synovial cavity (condyle & the articular disc) Only physiologic movement is rotation of the disc on the articular surface of the condyle – condyle- disc complex. Responsible for rotational movement in the TMJ. www.indiandentalacademy.co
  • 2) condyle-disc complex functioning against the surface of mandibular fossa; Free sliding movement possible, in the superior cavity. This movement occurs when the mandible is moved forward – translation.Articular disc is not a meniscus. Meniscus – is a wedge shaped crescent of fibrocartilage attached on one side to the articular capsule & unattached on the other side,extending freely into the joint spaces. - functions passively to facilitate movement. www.indiandentalacademy.co
  • The articular surfaces of the joint is maintained byconstant activity of the muscles that pull across thejoint, primarily the elevators. (even in resting stage ina mild tonus)Increase in intra articular pressure holds the joint.Width of the disc varies with the intra articularpressure. - low (closed rest position) – widens. - high (clenced) – space narrows. www.indiandentalacademy.co
  • Posterior border of the articular disc – retrodiscal tissues. Opening of the mandible – the superior retrodiscal tissue gets stretched, creating increased force to retract the disc. Mandible moves into full forward position & during its return – retraction force of the sup. retrodiscal tissue holds the disc rotated as far posteriorly on the condyle as the width of the articular disc permits. The sup retrodiscal tissue – only structure capable to retract the disc posteriorly on the condyle (wide www.indiandentalacademy.co
  • Anterior border of the disc – attachment of the superior lateral pterygoid muscle. (also attached to the neck of the condyle) Helps in protraction of the disc, dual attachment doesn’t allow the muscle to pull the disc through the discal space The inferior lat pterygoid when protract the condyle forward, the superior fibers is inactive – disc is not moved forward with the mandible. The superior lat pterygoid is activated only in conjunction with elevator muscles. (closure / power strokes) www.indiandentalacademy.co
  • During translation, the combination of disc morphology & interarticular pressure maintains the condyle on the intermediate zone – disc is forced to translate forward with the condyle. When the morphology of the disc has been altered, the ligamentous attachment of the disc affects joint function.Things to remember : ligaments;-do not actively participate in normal functioning of the TMJ-act as guide wires,restricting & permitting some movements www.indiandentalacademy.co
  • Ligaments do not stretch (ability to return to itsoriginal length)- traction force- elongates, if elongates then oftenthe function is compromised.Articular surfaces of the TMJs must remain inconstant contact (the elevators ; temporal,masseter, & medial pterygoid) www.indiandentalacademy.co
  • Mandibular rest position :-Physiologic rest position → muscle tonus of the elevator muscles → myostatic reflex (affected by the wt. of the mandible)-Rest position → 1.3 – 3.0 mm of interocclusal clearance (freeway space)- Changes with head posture & muscle tonus.-Varies with head position, total body posture, functional activities, fatigue, time of day, age & emotional tension. www.indiandentalacademy.co
  • VERTICAL DIMENSION OF OCCLUSION Increase in VDO → increased activity in the elevator muscles, with pain & resulting in dysfunction.Akagawa et al;- within interocclusal clearance displayed → transient acute inflammation in the deep & superficial masseter muscle.- more than 1mm → early acute inflammation to muscle fiber regeneration in the deep masseter, with a lesser degree in superficial masseter & ant. temporal muscle.Carlson et al;- VDO can be altered by using bite planes, without affecting muscle tonus of the mandibular muscles. www.indiandentalacademy.co
  • Examination of TMJ in ORTHODONTIC CLINICS Posture of the clinician & patient Palpation – in closed, at rest & various open position Deviation should be noted Crepitus / abnormal sound Palpation of the neck & sub mandibular area Speech evaluation www.indiandentalacademy.co
  • Palpation in•closed•open•wide open www.indiandentalacademy.co
  • Standards for TMJ evaluation: pediatric dentistry 1989- 11(4);330 History ;1) Does your child report any pain during chewing / while opening the mouth wide?2) Child report any discomfort in the jaws upon awakening3) Child complains of headache4) Any history of trauma to the jaws or neck region?5) History of allergies?6) Jaw click / lock upon opening? www.indiandentalacademy.co
  • +ve history – pain manifestation, stress, balanced diet, sleeping postureClinical examination : gentle & cautious palpation of muscles of mastication. - for trigger points - rated, 0 – no pain ; 1- tenderness ; 2 – definite pain ; 3 – evasive action. www.indiandentalacademy.co
  • Range of movement :-maximum opening & lateral excursions-widest opening – 40mm-anterior bite depth – 34mm-overbite – 6mm Click :-early, late, or both on opening. Radiographic examination & advances :- transcranial radiographs / tomograms- MRI & arthrograms www.indiandentalacademy.co
  • Temporomandibular disorders in children: Jeffrey P.Okeson Are TM disorders a problem in children ? How TM disorders treated in children ? Can early treatment prevent TM disorders ? www.indiandentalacademy.co
  • Are TM disorders a problem in children?-epidemiologic studies – 10-18 yrs.-studies place the findings into two categories via; a) symptoms b) signs-common in young population – few complain How are TM disorders treated in children?-Ingerslev – conservative & reversible-occlusal appliance - < 2 months www.indiandentalacademy.co
  • Two major categories : a) masticatory b) disc- interference / internal dearangements Can early treatment prevent TM disorders? -etiology is of paramount importance -occlusal condition -no scientific evidence www.indiandentalacademy.co
  • Prevalence of TMJ disorders in children Eup J.orthod 14;152-161:1992 A longitudinal study,for the signs & symptoms of CMD in 12-15 yr old individuals. “during this period there is an increased prevalence of S/S of CMD. In particular true for headache & joint sounds. www.indiandentalacademy.co
  • Heritability of TMJ disorder signs & symptoms J dent.res 79(8):1573-1578,2000.Genetic variance & environmental variancesThis study results suggest that neither shared genesnor the family environment accounts for much ofvariance in TMJ related s/s & oral habits.TMJ-pain was reported by 8.7% of the twins – Liptonet al 1993.Joint noises & locking in these twins were also aboutas prevalent as in non-twin population.Pain reporting in particular is influenced by mood,stress, learned behaviors, physiological painthreshold.- Mogil et al 1996. www.indiandentalacademy.co
  • They concluded thati) Genetic factor do not influence joint disorders manifesting pain. orii) Pain perception factors are non-genetic, supported by twin study of pain threshold – Mac Gregor et al ; 1997.So till date no study has substantial evidence of any genetic relation of joint pain. www.indiandentalacademy.co
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  • HARD TISSUE IMAGING:•Panoramic projection•Specialized TMJ radiography techniques: •Trans cranial •Trans pharyngeal • Trans orbital•Submento vertex (basal) projection•Conventional tomography•Computerized tomography (CT SCAN)SOFT TISSUE IMAGIMG:•Magnetic Resonance Imaging (MRI SCAN)•Arthrography www.indiandentalacademy.co
  • TRANS PHARYNGEAL TRANS CRANIALTRANS ORBITAL www.indiandentalacademy.co
  • OPGCONVENTIONALTOMOGRAPHY www.indiandentalacademy.co
  • ARTHROGRAPHY MAGNETIC RESONANCE IMAGING www.indiandentalacademy.co
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  • TMJ disorders – (intra capsular disorders) Physical examination- inspection for the pattern & the presence of noise / deviation on opening Normal vertical opening – width of three fingers Diff b/w maximal pain –free opening & maximal opening with pain Patient is asked to point the area of pain Muscle of mastication palpated Magnitude of opening ;Maximal incisal opening of less than 20-25mm- muscle spasmPeriauricular pain beginning at 25-30mm- TMJ capsulitis www.indiandentalacademy.co
  • Lateral movements ; > 5mm –well functioning TMJ normal lateral but painful vertical opening –muscle spasm 1 min clench test :- Tongue blade placed unilaterally on the posterior teeth –if hyperactivity muscle – ipsilateral pain- Capsulitis –pain on the contralateral side- Placed bilaterally – if pain relieved – splint therapy.TMJ noises :-click – 2-3 trials indicates disc displacement-during vertical & lateral motion. www.indiandentalacademy.co
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  • TMJ tenderness ; Patient open slightly bringing the condyle & disc from under the zygomatic arch. Retro discal area palpated – wide open mouth The surface posterior to the condyle is pressed Little fingers can be placed in the external auditory canal Lateral / posterior sensitivity – either capsulitis / synovitis or both. www.indiandentalacademy.co
  • Joint inflammation ;-synovial, capsular / retrodiscal tissues – capsulitis or synovitis-due to infection, trauma, systemic diseases, articular surface degeneration / disk displacement-preauricular pain-episodic swelling with occlusal changes can occur. TMJ dislocation (open lock)-subluxation-painful www.indiandentalacademy.co
  • Treatment of joint disorders –Patient’s educationPain free dietTherapeutic exercises to rehabilitate the jointAnti-inflammatory drugs &muscle relaxantsPhysical therapy –Heat / ice massageGentle range of motion exercises with in the paintolerance.( 6 times a day for 30-60 secs )Joint shouldn’t hurt more than 10mins after exerciseNight time splint – reduces forces on the joint. www.indiandentalacademy.co
  • Night guard, controls parafunctional habit, temporarystabilizes an uneven occlusion – allows the joint torest.Should have a flat plane – opening the bite severalmm.Soft night guard is given for children with developingocclusion / mixed dentition. www.indiandentalacademy.co
  • Painful click – mandibular orthopedic repositioningappliance www.indiandentalacademy.co
  • Extra capsular disorders -Acute disorders : Myositis- due to infection / injury Protective muscle spinting – constriction of muscles to avoid pain, pain in function Myospasm (acute trismus) – involuntary, sudden, tonic contraction of muscles www.indiandentalacademy.co
  • Chronic disorders : Myofacial pain –-most common in children-jaw function aggravates headache.-localized tender / trigger points (active / passive)-tender spots may produce characteristic pattern of referred pain. www.indiandentalacademy.co
  • -can be caused by postural problems, parafunctional habits, psychological disorders, stress & trauma.-pain is reduced / eliminated with anesthetic injection into active trigger points, or a spray & stretch procedure with fluormethane spray.-long term - elimination of the contributing factor.-analgesics, muscle relaxants, behaviour modification & home rehabilitation & physical therapy. www.indiandentalacademy.co
  • Myofascial Pain – Dysfunction Syndrome (MPDS) or Temporomandibular Joint Pain Dysfunction Syndrome or Masticatory Myalgesia Syndrome Schwartz in 1955. Etiology :- masticatory muscle spasm, due to muscular overextension / muscular over contraction / muscle fatigue.- habits like clenching / grinding- Laskin et al – the “psycho- physiologic theory”- occlusal disharmony – altered chewing pattern. www.indiandentalacademy.co
  • c/f ;- 80% - 90% - females (< 40yrs) Four cardinal signs : Pain Muscle tenderness Clicking / popping noise in the joint Limitation of jaw motion (unilaterally / bilaterally) Two typical –ve disease charecteristics Absence of clinical, radiographic / biochemical evidence of organic changes in the joint & Lack of tenderness in the joint. www.indiandentalacademy.co
  • Treatment :-conservative-relief of emotional factors, faulty restorations & appliances-myotherapeutic exercises & physiotherapy-drugs ; tranquilizers & muscle relaxants. www.indiandentalacademy.co
  • Correlation b/w occlusal characteristics & TMD JCPD 24;229-236 ; 2000 Study showed a significant correlation b/w posterior cross bite & TMD. Egermark – Erikson –association b/w cross bite & muscle tenderness. 1985 – Brandt compared cross bite to clicking, significant. Anterior openbite & edge to edge relationship with TMD- Egermark – Erikson –frontal openbite & crossbite may predispose to mandibular dysfunction.- Seligman & Pullinger –ant openbite was the variable with the greatest influence on the presence of TMJ www.indiandentalacademy.co tenderness.
  • They concluded that :Significant correlation was found b/w TMD & a) posterior crossbite b) openbite & edge to edge occlusion c) class III canine relationship. www.indiandentalacademy.co
  • Congenital abnormalities of TMJ: Hemifacial microsomia (HFM) ;-variable, progressive, & asymmetric craniofacial deformity-involves the skeletal, soft tissue & neuromuscular components of the 1st &2nd pharyngeal arch-Poswillo – hemorrhage from the developing stapedial artery produces a hematoma in the area of the 1 st & 2nd arches. Facial growth :- asymmetric mandibular growth (unilateral / bilateral)- growth is impaired with short, retrusive & narrow www.indiandentalacademy.co
  • Classification Acc to skeletal defects Type I – consists of a mini-mandible & TMJ -all str. are present, normal in shape & location but small Type II – small mandible with a hypoplastic TMJ i) type II A degree & location of hypoplasia ii) type II B Type III – complete absence of ramus & TMJ. www.indiandentalacademy.co
  • Hemifacial microsomia www.indiandentalacademy.co
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  •  Acc to jaw motion & dev of muscles of mastication Type I –- both jaw motion, articular disc & muscles present.Type IIA & B –- hypoplastic, muscles of mastication & articular disc- translatory & lateral movements are restricted.Type III – - lateral pterygoid & articular disc are absent- moderately to severely hypoplastic temporalis, masseter & medial pterygoid.- doesn’t translate to affected side & move medially towards the normal side www.indiandentalacademy.co
  • End stage of skeletal defect :Short, medially, placed ramus & TMJ.Mandible – flat in contour & chin point deviatedtowards the effected side.Short midface – resulting in a canted occlusal plane( ↓ distance b/w the infraorbital rim, piriformaperature, & maxillary alveolus)Flat zygomatic bone, orbit sometimes is inferiorlypresent www.indiandentalacademy.co
  •  Acc to soft tissue defects: Mild ;- minimal subcutaneous & muscle hypoplasia.- absence / slight macrostomia- mild auricular defect (pre-auricular tags) Severe ;- severe hyploplasia- subcutaneous & muscles- facial clefts- macrostomia- neuromuscular weakness Moderate www.indiandentalacademy.co
  •  Acc to ear anomaly ( Meurman) Grade I ; mild hypoplasia & cupping Grade II ; absence of external auditory canal & hypoplasia of conchae Grade III ; auricle is absent, anteriorly & inferiorly displaced lobule. Conductive hearing loss – hypoplasia of ear ossicles. www.indiandentalacademy.co
  • OMENS classification : Vento et al O – Orbit M – Mandible (& TMJ) E – Ear N – Nerves S – Soft tissues www.indiandentalacademy.co
  • Scoring ;Orbit – 0 -normal Mandible – 0 -normal 1 -abnormal size 1 -type I 2 -position 2A -type II A 3 -both 2B -type II B 3 -type IIIEars – Meurman’s systemNerves – Facial defect Soft tissues – 0-normal -no involvement 1-mild -upper, lower / all branches www.indiandentalacademy.co 2-
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  • Treacher Collins syndrome : mandibular dysostosis• Autosomal dominant• Due to an insult to the neural crest cells (4-6 weeks of embryogenesis)c/f ;Treacher collin (1900)• anomalies are bilateral & symmetrical• Antimongoloid (downward) cant of the palpebral fissure• Colomba at the junction of outer & middle 3rd of lower eyelids• Absence of eyelashes• Ears are low set & hypoplastic www.indiandentalacademy.co
  • • Nose is large, the zygomatic bones & arches are hypoplastic or missing• Frontozygomatic suture is inferiorly displaced –orbits are “tear drop” in shape. www.indiandentalacademy.co
  • Bilateral facial microsomia :• They have similar skeletal deformities• Do not show charecteristic soft tissue defects around the eyelids.• Asymmetrical defect• No inheritance pattern www.indiandentalacademy.co
  • Developmental disturbances :Aplasia of the condyle – a) unilateral b) bilateral c/f –-anatomically related defects ; defective or absent external ear, an underdeveloped ramus or macrostomia.-facial assymetry Treatment –-osteoplasty (if derangement is severe)-orthodontic appliance-cosmetic correction – correcting facial deformity. www.indiandentalacademy.co
  • Hypoplasia of condyle a) congenital b) acquiredCongenital hypoplasia : (idopathic) Unilateral BilateralAcquired hypoplasia : Forcep delivery External trauma X-ray radiation for local treatment of skin lesions Infections Endocrine or vitamin derangement www.indiandentalacademy.co
  • c/f –a) depends on its effect on one / both condyleb) degree of malformationc) age of the patientd) duration of injury & its severityUnilateral (common) – Facial asymmetry Limited lateral excursion Mandibular midline shift during opening & closingdue to lack of downward & forward growth of the body of www.indiandentalacademy.co
  • Treatment & prognosis :-poor as there no means to stimulate growth locally-cartilage or bone transplants-costochondral grafts to mimic condylar head &- metatarsal grafts has shown growth potential www.indiandentalacademy.co
  • Hyperplasia of the mandibular condyle-unilateral in most cases resembling an osteoma or chondromac/f – - pt exhibits a unilateral ,slow progressive elongation of the face with deviation of the chin away from affected side. -condyle evident clinically & palpable -striking radiographically appearance in AP& lateral view. -may or maynot be painful -severe malocclusion.Treatment - - resection of the condyle - correction of facial asymmetry www.indiandentalacademy.co
  • Ankylosis (hypomobility)Etiology: Straith & Lewis Abnormal IU life Birth injury Trauma to the chin Malunion of condylar # Loss of tissue with scarring Congenital syphilis Primary inflammation of the joint Secondary inflammation to a blood stream disease Metastatic malignancies Inflammation secondary to radiation therapy www.indiandentalacademy.co
  • c/f –-any age group-before age of 10 yrs-both sexes affected-difficult in opening mouth. Complete ankylosis;-bony fusion with limited motion-associated with facial deformitya) Unilateral ankylosis- -the chin is displaced laterally & backward on the affected side www.indiandentalacademy.co
  • b) bilateral ankylosis ;-maxillary incisors manifests over jet due to failure of the mandibular growth.TMJ ankylosis : a) intra-articular b) extra- articularIntra-articular – joint undergoes progressive destruction of the articular disc with flattening of the mandibular fossa.Extra-articular – splinting of the TMJ by a fibrous / bony mass external to the joint proper (as in infections)Treatment is surgical (osteotomy) www.indiandentalacademy.co
  • Injuries to the articular discEtiology :MalocclusionEpisode of acute trauma to the jawInflammatory conditions c/f : Common in female Young adults & persons > 40yrs Characterized by,- pain- snapping / clicking & crepitation in the joint area- transient / prolonged locking of jaw www.indiandentalacademy.co
  • s/s ;-pt.may complain of dull pain in & around the ear or on the side of the jaw, with tinnitus, & dysesthesia of the tongue reported in some cases.Diagnosis -radiographs in both open & closed position.Treatment – -immobilization of jaws- severe pain -malocclusion correction -meniscetomy www.indiandentalacademy.co
  • Inflammatory disturbances of the TMJArthritis / inflammation of the TMJ : Due to infection Rheumatoid Osteoarthritis / degenerative joint disease. Due to specific infection ;- resulting from gonococci, streptococci, staphylococci, pneumococci & tubercle bacillus (polyarticular involvement)-gonococci effects the joint – Markowitz & Gerry. www.indiandentalacademy.co
  • c/f :-severe pain with tenderness to palpation-motion is severely limited-healing results in ankylosis (osseous or fibrous) Treatment :-antibiotics-acute phase –less deforming-chronic phase / advanced stage – menisectomy or condylectomy www.indiandentalacademy.co
  • Rheumatoid arthritis :Etiology :-idiopathic-early adult life-female : male -2 : 1c/f :-polyarticular & bilateral-episodic exacerbations & remissions-early stages : low fever, loss of wt & fatigability.-joint are swollen, pain & stiffness www.indiandentalacademy.co
  • Still’s disease :-may cause a malocclusion of the class II div I type, with protrusion of the maxillary incisors & an anterior openbite.-radiograph reveal flattening & stunting of the condyles & haziness about the joint indicative of periarticular fibrosis. Treatment :-administration of ACTH / cortison-limitation of motion – condylectomy . www.indiandentalacademy.co
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  • “ The clinician who only looks at occlusion is missing as much as the clinician who never looks at occlusion. ” OKESON www.indiandentalacademy.co
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  • References :Management of Temporomandibular Disorders &occlusion -JEFFREY P.OKESONDiseases of the temporomandibular apparatus - DOUGLAS H. MORGANPediatric oral & maxillofacial surgery - L B.KABANOral anatomy, histology & embryology - BERKOVITZDCNA –vol.27,no.3,july 1983Bell’s orofacial pain -5th ed. www.indiandentalacademy.co
  • •Orthodontics & the temperomandibular joint: whereare we? Part 1: orthodontic treatment and TMJdisorders. The Angle Orthodontist:vol. 68, no.4 -295- 304•Orthodontics & the temperomandibular joint: whereare we? Part 2:functional occlusion,malocclusion,&TMD. The Angle Orthodontist:vol. 68, no.4 -305- 318.•Prevalence of TMJ disorders in children :Eup J.orthod14;152-161:1992•Heritability of TMJ disorder signs & symptoms:J dent.Res 79(8):1573-1578,2000.•Standards for TMJ evaluation: pediatric dentistry 1989-11(4);330 www.indiandentalacademy.co