Temporomandibular Disorders I

9/11/2025 and 9/25/2025 RAT LECTURE- needs sample questions added once posted (or will be their own knowt)

temporomandibular disorders

a collective term embracing a number of clinical problems that involve the masticatory musculature, TMJs, and associated craniofacial structures

list some etiologies of TMD

trauma, emotional stress, deep pain input, parafunctional activities

*are occlusal factors an etiology of TMD?

no, occlusal factors do not really directly cause TMD- this is an outdated belief

what did Costen assert in 1934?

etiology of TMD was the loss of VDO and a deep bite, this triggered the concept that occlusion is the main etiological factor in TMD

do occlusal conditions like

anterior open bite, increased overbite, excessive overjet, premature contacts (occlusal interferences), posterior cross bite, CR and CO difference

mean the patient will have TMD?

no- subjects with similar occlusal conditons may not develop similar disorders because there are many contributing factors

is the claim that posterior cross bite causes TMD as a result of asymmetric muscle functions valid?

no- there is no conclusive evidence that suggests that posterior crossbite is a risk for TMD

is the claim that increased positive and negative overjet increases the risk of TMD valid?

no- no correlation has been found between increased negative or positive overjet and TMD

is the claim that deep bite with minimal overjet limits the free anterior mandibular movement and therefore causes TMD valid?

potentially- deep bite patients (in particular ones with retroclined maxillary incisors) frequently report jaw stiffness and muscle disorders and this may represent a risk factor for TMD

is the claim that CR to CO slide may cause TMD valid?

potentially- CR to CO slide more than 4 mm may be a risk factor

is the claim that canine guidance and anterior guidance may eliminate TMD symptoms valid?

no- there is no evidence showing the superiority of canine guided occlusion vs other types of functional occlusion (balanced, group function)

is the claim that anterior open bite prevents normal TMJ function and aggrivates myofascial pain valid?

no- subjects with similar occlusal conditions may not develop similar disorders because there are many contributing factors

how often is ideal occlusion seen in real life?

seldom

*does non ideal occlusion need to be corrected ASAP?

no, the patient may still function well, and it is physiologically acceptable, so there would be no need for intervention (besides monitoring)

*if a patient with non ideal occlusion has TMD, would you recommend ortho just for TMD treatment?

no!

is occlusion completely unimportant to TMD?

no- acute changes in occlusion may cause muscular problems

list some acute changes in occlusion that may cause muscular problems

improper crown and filling, changes occlusal vertical dimension, improper occlusal appliances or splints

can TMD affect occlusion?

yes

what might happen to a patients occlusion if they have capsulitis, synovitis, or retrodiscitis?

may cause open bite and/or occlusal discomfort

what might happen to a patients occlusion if they have osteoarthritis or rheumatoid arthritis?

open bite

what might happen to a patients occlusion if they have a protective co-contraction of muscles?

a perceived change in the occlusion

*there is no proof that malocclusion causes TMD, so any attempt to change the occlusion to treat TMD should be…

avoided

acute occlusal changes may not be tolerated well by the patients and can cause?

TMD

TMD may cause occlusal changes (bite change), therefore any dental treatment should be performed ____ the problem is resolved

after

TMD joint disorders

disc displacement with reduction, disc displacement without reduction, dislocation / subluxation, inflammatory disorders, non-inflammatory disorders

TMD muscle disorders

protective co-contraction, local muscle soreness, myofacial pain, myospasm, centrally mediated myalgia

what are characteristics of normal joint junction?

mandibular movement without pain or discomfort, full range of motion for an adult is 40-60mm of opening, free of noise/clicking/crepitation

t/f 80% of young adults have detectable click, and it is always pathological

false- 80% is true, but it is not always pathological

*joint noises without pain and dysfunction do not require treatment however…

they should be followed up

disc displacement

disturbances of the normal anatomical relationship between the disc and the condyle

what are some etiologies of disc displacement?

trauma, parafunction, spasam of the superior lateral pterygoid, disruption of lubrication system

what is an example of how prolonged overloading can lead to disc displacement?

affects disc viscoelastic properties, affects lubrication, or repeatative disc hesitation causing elongation which leads to disc displacement

disc displacement with reduction general characteristics

reciprocal click (click on opening and closing), pain may be present upon joint movement, deviation of mouth opening, *unrestricted maximal mouth opening

disc displacement without reduction general characteristics

*limitation of mouth opening (<35mm), deflection to the effected side on mouth opening, markedly limited contra-laterotrusion, pain on forced mouth opening, history of clicking (ceased), affected TMJ tender to palpation

disc displacement with reduction deviation

any shift of the midline during opening that disappears with continued opening

no limitations during excursive movements

disc displacement without reduction deflection

any shift in the midline to one side that becomes greater with opening and does not disappear at max opening

*limitation to the contralateral side during lateral excursion

*limitation during protrusion and deflected to the affected side

most of the time, disc displacement with reduction (does/does not) progress to the next stage of disc displacement without reduction

does not- only 7% progresses

what is the education treatment for patients with disc displacement with reduction?

explanation of disorder, clarify the cause, adaptive process of the retrodiscal tissue is essential for successful treatment, softer foods, smaller bites, no chewing gum, no opening wide, should not allow click when possible

what is the medication and physical therapy treatment for patients with disc displacement with reduction?

NSAIDs (600mg 3x a day for 10 days) if inflammation is suspected, ice application, *no active exercise

what is the other treatment for patients with disc displacement with reduction?

use occlusal guard (splint)- stabilization splint, use at night and follow up after 3 weeks

gradually reduce use of the applicance with no need for any dental changes, tissue adaptation may take 8-10 weeks

what is the purpose of an occlusal guard (splint) for patients with disc displacement with reduction?

reduces forces on the retrodiscal tissue and pain, allows time for healing and for the retrodiscal tissue to adapt

what is the definitive therapy for disc displacement with reduction?

reduce intracapsular pain (NOT to recapture the disc)

encourage adaptation of the retrodiscal tissue

what measurement of max mouth opening is considered limited?

less than 40 mm

what measurement of excursive movements is considered limited?

less than 8mm

*in cases of disc displacement without reduction, which side experiences limited lateral excursive movement?

contralateral side

what is the education treatment for patients with disc displacement without reduction?

explanation of disorder, clarify the cause, adaptive process of the retrodiscal tissue is essential for successful treatment, softer foods, smaller bites, no chewing gum, no opening wide

what is the medication and physical therapy treatment for patients with disc displacement without reduction?

NSAIDs (600mg 3x a day for 10 days) if inflammation is suspected, ice application

after pain relief- controlled jaw exercises may be helpful to regain the mouth opening (may take a year or more)

if pain is not relieved, refer to oral surgery

what is the other treatment for patients with disc displacement without reduction?

use occlusal guard (splint)- stabilization splint, use at night and follow up after 3 weeks

gradually reduce use of the applicance with no need for any dental changes, tissue adaptation may take 8-10 weeks

what is the treatment for patients with acute disc displacement without reduction?

try to recapture the disc by manual manipulation (has to be done within a week of first occurence or there is less chance of success)

what is the treatment for patients with chronic disc displacement without reduction?

if patient has a long history of locking there is likely a loss of disc morphology

surgery or no surgery

if pain relieves with conservative treatment then stretching exercises should be used to increase the mouth opening

if pain continues then the patient should be referred to oral surgery

synovitis and capsulitis

usually following trauma to the tissue (micro or macrotrauma), localized TMJ pain, pain exacerbated by function/palpation/joint loading, pain may be present at rest, limited range of movement, fluctuant swelling over affected TMJ

how can you differentiate between synovitis and capsulitis?

differential diagnosis is difficult

retrodiscitis

inflammation of the retrodiscal tissue, macrotrauma (blow to the chin, ect), microtrauma (progressive disc derangement disorder), constant pain in the join area, clenching increases pain, limited jaw movement may be present

inflammation on the TMJ area can cause alterations in occlusion- any dental treatments should be _____ until the inflammation is fully resolved- this includes occlusal adjustments

avoided

what are suggested treatments for synovitis and capsulitis?

if it is due to trauma then it is self limiting

soft diet, small bites, NSAIDs (600mg 3x a day for 10 days), moist heat or ice applications (10-15 min 5x a day), single corticosteroid injection to TMJ (by os), parafunction control with splint stabilization

what is the treatment for retrodiscitis?

trauma like blow to the chin: patient will report the incident, similar therapy approach to synovitis and capsulitis

disc displacement: patient will report gradual onset of the problem, similar therapy to the disc displacement with reduction

osteoarthritis

characterized by destructive process by which the bony articular surfaces of the condyle and the fossa become altered

overloading exceeds joint repair capacity

what will you see upon clinical examination of a patient with osteoarthritis?

TMJ pain localized to the joint, TMJ tenderness to palpation, crepitus, limited range of movement

what will malocclusion look like during the repair process of osteoarthritis if both condyles are affected?

anterior open bite

what will malocclusion look like during the repair process of osteoarthritis if one condyle is affected?

contralateral side open bite

*what can you see radiographically that points to osteoarthritis?

condylar deformities, erosion, osteophyte (bone spur), reduced joint space

what is the treatment approach for osteoarthritis?

NSAIDs (400mg 3x a day for 10 days), stabilization splint to reduce joint loading, parafunction and stress control, soft diet, avoid painful habits, passive muscle exercises within painless limits to avoid myofibrotic contracture of the muscles, self limiting disorder but treatment will reduce symptoms and speed up the adaptive process

what happens if osteoarthritis cannot be managed with conservative therapy?

oral surgery referral may be required

subluxation

condyle is positioned anterior to the articular eminence, jaw clicking that is dissimilar to disc displacement, observed after wide opening, lateral pole can be felt or observed, depression in the preauricular region

dislocation (open lock)

inability to close the mouth without specific manipulative maneuver, radiographic evidence reveals condyle well beyond the eminence, pain at time of dislocation with mild residual pain after the episode

*t/f if a patient has left disc displacement without reduction, you would expect to observe limitation during left lateral movement

false

*t/f if a patient has right disc displacement with reduction, you would expect to observe limitation during left lateral movement

false

*t/f if a patient has right disc displacement without reduction, you would expect to observe deflection during maximum mouth opening to the left side

false