TMJ Flashcards
What are 5 causes of TMJ dysfunction?
- Macrotrauma (e.g. whiplash, direct blow, iatrogenic dental procedures)
- Microtrauma from parafunctional clenching and bruxing
- Degenerative OA
- Systemic conditions
- Mental health disorders
What population is at highest risk for TJM dysfunction?
Women around reproductive age
TMJ is what type of joint?
Bilateral diarthrodial (synovial) joint
TMJ articular surfaces and the disk are covered in what?
Fibrocartilage that has superior reparative potential and resistance to wear/tear
During mouth opening what movement occurs?
Superior cavity: translation
Inferior cavity: rotation of the condyle
What is the shape of the disk in the TMJ?
Biconcave (“bow-tie”)
What parts of the TMJ articular disks have innervation/vascularization?
Anterior & posterior
What is the function of the temporomandibular ligament aka “lateral” ligament?
Limits rotation of the condyle and posterior displacement
What is the function of the collateral ligaments?
Restrict excessive medial/lateral movement of the disk
What are the 2 accessory ligaments of the TMJ?
Stylomandibular and sphenomandibular ligaments
What is the function of the accessory ligaments in the TMJ?
Restrict excessive protrusion
What are the muscles of mastication?
- Masseter
- Temporalis
- Lateral pterygoid
- Medial pterygoid
What is the action of the masseter muscle? (both unilat & bilat contraction)
Unilat: slight ipsilat excursion
Bilat: superficial = protrusion, deep = retraction
What is the insertion of the temporalis muscle?
Coronoid process and medial border of the mandibular ramus
What is the action of the temporalis muscle? (both unilat & bilat contraction)
Unilat: ipsilat lat excursion
Bilat: elevation/retraction of mandible
What is the function of the medial pterygoid?
Unilat: contralat excursion
Bilat: elevation/protrusion
What is the function of the lateral pterygoid?
Unilat: contralat excursion
Bilat: protrusion
What are the suprahyoid muscles (4)?
anterior/posterior belly of the digastric, mylohyoid, geniohyoid, and stylohyoid
What are the infrahyoid muscles (4)?
sternohyoid, sternothyroid, thyrohyoid, and omohyoid
Muscles involved in TMJ elevation (closing)
Masseter, temporalis, medial pterygoid, lateral pterygoid (SUPERIOR)
Muscles involved in TMJ depression (opening)
Lateral pterygoid (INFERIOR), suprahyoids, infrahyoids
Muscles involved in TMJ protrusion
Massater (SUPERFICIAL), lateral pterygoid, medial pterygoid
Muscles involved in TMJ retrusion
Massater (DEEP), temporalis, suprahyoids
Muscles involved in TMJ lateral excursion
IPSILAT: masseter, temporalis
CONTRALAT: medial/lateral pterygoids
Innervation of the TMJ
Mandibular division of the trigeminal nerve (CN V3)
Ant/medial: deep temporal and masseteric nerve
Post/lat: auriculotemporal nerve
Normal amount of TMJ depression
40-45mm Males
45-50mm Females
aka 4 fingers width
FUNCTIONAL amount of TMJ depression
35mm or 3 fingers width
Lateral excursion normal movement (measurement)
1/4 opening amount
Protrusion amount
6-9mm
Retrusion amount
3mm
Primary arthrokinematics movement in first 25-50% of opening
Anterior rotation of condylar head
Primary arthrokinematic movement in LATE opening
Anterior translation of condylar head and disk
2 classifications of internal derangement of the disk-condyle complex
- Anterior disk displacement WITH reduction (ADDwR)
- Anterior disk displacement WITHOUT reduction (ADDwoR)
Where is the resting position of the TMJ disk when mouth is closed?
Just anterior to condyle
What type of clicks in ADDwR?
reciprocal clicks (can be single though)
If ADDwR is not treated, it may become?
ADDwoR = no clicking, limited opening ROM
What is open-lock?
Disk displaced posterior, lateral pterygoid is overly stretched
How many teeth in the mouth?
32
Orthognathia
Dentist who deals with the malposition of bones of the jaw
Stomatognatic system
Includes the structure of mouth, teeth, jaw, and associated soft tissues
Overbite
Portion of the mandibular central incisors that are covered by the maxillary central incisors
- NORMAL: 1/3rd of mandibular incisors
Overjet
Horizontal distance between maxillary arch and mandibular arch when in max occluded position
- NORMAL: 3-6mm
What does the “C” curve indicate during opening?
capsular pattern
What does the “S” curve indicate during opening?
Poor motor control (muscular imbalance) or asymmetry of condylar head rotation or translation, ADDwR
Deflection
Mandible deflects to one side w/o returning to center at end of opening
- CAUSE: capsular restriction or unilat hypomobility
Classes of occlusion
I: normal (overjet 3-6mm)
II: excessive overjet >6mm
III: underbite
Open-bite
Maxillary front teeth don’t make contact while mouth is closed
Crossbite
central incisors not aligned when mouth is closed
Centric relation
Position where the condyle sits most sup/post in mandibular fossa
(aka “Open packed position”)
Bruxism
Excessive teeth grinding
3 Classifications of TMD (according to AAOP)
- Articular disorders
- Masticatory muscle disorders
- Arthritides (capsulitis, OA, synovitis, RA)
Recommended questionnaires (Harrison et al) for TMD
- Patient health questionnaire for depression and anxiety
- Graded chronic pain scale
Type of imaging that can confirm clinical suspicion of anterior disk displacement with or without reduction
Kinematic MRI
Deflection can be due to..?
- ADDwoR
- Limited capsular mobility
- Unilateral hypermobility
Scalloping of the tongue could indicate?
Nocturnal bruxism
T/F: Joint sounds and deviations of the jaw do not indicate significiant pathology?
True
Cotton roll test: Pain increases = ?
Pain decreases = ?
Increases = muscular in origin
Decreases = joint (can confirm by biting down on contralat side - should cause pain on involved side due to loading of the joint on that side)
T/F: US (diagnostic) is NOT reliable in identifying internal derangement
False
Also helpful: MRI, XR, CT
Cluster to diagnose chronic ADDwoR (5/7 = +)
- Joint provocation test (mouth opening w/ pain)
- Deviation test (deflection to ipsilat side at end-range opening)
- Laterotrusion test (limited lat excursion <9mm to contralat side)
- Joint mobility test (reduced ant translation of condylar head w/ palpation)
- Joint sounds test (absent or crepitus)
- Dental stick test/cotton roll test
- Isometric test (resist lat excursion contralat, + painful)
What can cause open lock?
Prolonged opening (dentist), excessive yawning/laughing
Hypomobility with opening (in mm)
<30mm
Hypermobility with opening (in mm)
> 55mm (usually with “S” deviation)
T/F: myofascial pain is the most prevalent cause/form of TMD?
True
Trismus
Acute closed lock of the jaw after a dental procedure
Interventions for dystonia in TMJ muscles
botox & medication
T/F: Vertigo is more prevalent in those with TMD
True
Trigeminal neuralgia symptoms
Sudden/paroxysmal, unilat, electric-like, stabbing pain, intermittent, abates in seconds-minutes
- Involves maxillary/mandibular divisions of the trigeminal nerve
3 branches of the trigeminal nerve
Ophthalmic (V1), maxillary (V2), and mandibular (V3) nerves
Meniere’s disease symptoms
Vertigo, tinnitus, aural fullness, facial-TMJ pain
What is the first line for TMJ treatment?
Non-surgical options: PT, medication, occlusal adjustment, splint therapy, chiro, cognitive behavioral therapy
Sleep posture that should be avoided in pt’s with TMD
Prone
Diet recommended for TMD
Soft or semi-solid until symptoms subside
Is TENS okay to use for TMD?
Yes, it is superior to a placebo
T/F: manip of TMJ is indicated for acute closed lock (ADDwoR) or dislocation
True
Evidence for dry needling in TMD
Positive effect
KT taping in conjunction with what is shown to be effective
KT in combo w/ exercise & counseling was MORE effective then counseling and exercise alone
Directions of joint mobilization of TMJ
- Longitudinal distraction
- Anteromedial translation
- Medial glide (rarely performed)
- Lateral glide
Tongue-controlled mouth opening exercises can be helpful for __?
hypomobility, hypermobility, incoordination, and inflammatory conditions
Recommended sets/reps for tongue controlled mouth opening exercises
3 x 6 reps, 6x/day
Progress to wider opening without tongue on palate when opening pattern no longer shows deviations or deflections
Controlled opening should be progressed to –> ___?
Isometrics
Recommended reps/hold time for TMJ isometrics
10” hold x 6 reps each session
What is spray and stretch and how is it helpful?
Use of Ethyl-Chloride or Flouri-Methane vapocoolant spray; thought that coolant can abolish superficial stretch reflex of the fascia
Treatment of myofascial pain disorder syndrome should focus on what?
Elimination of trigger points, reduction of precipitating and perpetuating factors
What is the most effect approach to tx of myofascial pain disorder?
Multidisciplinary, cognitive behavior therapy and patient education are key
When is persistent pain deemed chronic
6 months
First choice medication for arthritide TMD
Acetaminophen, can use NSAIDS for inflammation
What topical medication is demonstrated to be effective in reducing TMJ pain?
Topical diclofenac
What is the evidence of use of acupuncture in TMD?
Limited, weak
Is occlusal adjustment a good tx for TMD?
Not recommended as first line, efficacy has not been proven
2 schools of thought on TMJ splinting
- Stabilization theory (Michigan type splint)
- Repositioning theory (Farar type, Gelb type)
Better vs no tx, but not super effective
What is the connection pathway between TMD and ear symptoms
Trigeminocervical nucleus
T/F: Upper cervical spine mobs are important in the management of non-otological tinnitus
True, C1-C3 nerves are located in the trigeminocervical nucleus
