TMD Research:

1. 30 yrs ago, dentistry studied teeth as only cause
2. 20 yr ago, studies revealed causes were joint, muscle, & disc related
3. 10 yrs ago, science indicated TMD was orthopedic science

Tearing Lateral Ligament-TMD Disc

1. Primary Damaged:
   1. Clenching/grinding
   2. Tension muscles
   3. Trauma-MVA, Falls, Blows
   4. Neighboring pains (head & neck pain)
2. Secondary damage:
   1. dual bites
   2. pain system escalation
   3. malocclusion
   4. open lock

CONFUSION TERMS in TMD World:

1. TMD=name of joint not disease,
2. TMD=broad collection structural damage all tissues chewing system
3. Internal Derangement= structural damage to TMD
4. Articular Disc Displacement = pathologies specific to disc
5. Relationship disc to condyle: mild----moderate----severe

Relationship disc to condyle

1. Mild =Partial Displaced Disc
2. Moderate = Completed Disc Displacement
3. Severe = Osteoarthritis

Mild disc displacement

1. Includes: Muscle discomfort & partial disc displacement
2. General dentist should treat or try prevent further damage
3. Dentist needs to study this area of health for their patients
4. Repeated recommendations prevent joint muscle damage
5. Tooth damage we can treat but joint muscle damage is difficult treat
6. Early mentioning of grind-clench makes appliances easier prescribe
7. Early recognition of accumulative damage to all 4 chewing structure
8. Early referral to OFPS in saga of atypical toothache reduces damage chewing structures
9. Early recognition of anxiety issues coupled w/ TMD issues makes refer easier
10. Recognition of accumulative trauma creates need for better history base

Moderate damage = need for referral to Orofacial Pain Specialist:

1. Moderate chewing pain
2. Restricted opening
3. Referred ear pain
4. Deviation opening
5. Facial asymmetry
6. Comorbid: Hypermobility, IBS, Sleep, Allergies, Sinus,
7. High anxiety, need dental sedation, fear dentistry, PTSD, OCD, Bipolar
8. Clenching & grinding
9. Neighboring pains: neck and headache
10. Atypical Toothache
11. Burning mouth
12. Trigeminal nerve injury
13. Atypical earache
14. Sleep apnea & TMD

Four primary factors

• Destructive Clench-Grind ( higher level grinding)
• Significant Tension muscles (back, neck, jaw, head)
• Trauma (MVA, Blows, Falls)
• Head & Neck pain (jaw muscle bracing due pain in neck or head)

Four secondary factors

• Open lock (subluxation TMD)
• Pain System Escalation
• Dual Bite (jaw jt bite vs tooth bite)
• Major Occlusal interferences-bite discrepancies

Tearing Lateral Ligament: assume 10, 000 fibers

1. Age 12-26: habit clench/ grind tears 2 fibers per week = 1248 fiber
2. Age 12-26: high muscle tension tears 1 fiber per week = 624 fibers
3. Total Para tears (1248) + Tension tears (624) = total 1872
4. MVA: moderate speed 25 mph: age 26 = tearing 828 fibers
5. Age 26 to 36, habit clench/grind tears 4 fibers per week = 2496 fibers.
6. Ager 26 to 36, tension in muscles tears 2 fibers per week =1248 fibers.
7. Total Para tear (2496) + Ten tear (1248) = total 3744
8. Total tearing by parafunction & tension muscles & MVA: 6444
9. By age 36, She has torn over half of fibers of lateral ligament of TMD & has complete displace disc

TEARING LATERAL LIGAMENT A) MAJOR (TENSION, GRIND-CLENCH, TRAUMA, NEIGHBOR PAINS) B. MINOR: (OPEN LOCK, DUAL BITE, OCCLUSION, PAIN SENSITIZATION)

Destructive Clench/Grind:

Three levels grinding/clenching

1. Mild
2. Moderate
3. Destructive

Symptoms destructive clench-grind

1. Tooth movement after ortho
2. Recession/bone loss
3. Cracks-Broken fillings, teeth, crowns, bridges
4. Loose implants
5. Broken, cracked, chipped appliances
6. Worn out dentition
7. Failed implants
8. Broken retainers, brackets, spacers
9. Atypical toothace
10. Atypical earache
11. Cervical erosion
12. Enlarging tori, bone buttressing
13. Loose crown or bridges
14. Build-ups broken off inside crown
15. Tooth pain after cementation crowns
16. Worn out night guards-biteguards in short time

Grinding/Clenching:

1. Daytime: clenching, posturing, bracing, gnashing, nail biting, tongue biting, cheek biting, lip biting
2. Nighttime grinding is more destructive due power at night exceeds the chewing power by 6 times.
3. Need to measure power, frequency, and duration to determine damage potential
4. Sleep studies measure breathing, sleep architecture, and grinding activity (only source data)
5. Clenching & grinding damage all structures of chewing system: TEETH, BONE, MUSCLE, JOINT

Tension in Muscles

Three processes occur from anxiety/stress:

1. CORTISOL
2. ADRENALIN
3. TENSION MUSCLES

Levels of tension in muscles:

1. STRESS
2. ANXIETY
3. EMOTIONAL HYJACKING
4. PTSD

Muscle Joint Pain is #2 pain world:

1. BACK
2. NECK
3. HEAD
4. JAW

Tension in Muscle Pathway:

Stress---Sympathetic---Gamma Efferent--Muscle spindle-- Tr Pt --Muscle Inflammation--PAIN

Ligament Tear:

Stress- Sympathetic-Lat Pterygoid-Pulls Lateral Ligament-Stretch-Tear Lat Lig- Disc Disp--PAIN

Progression Tearing:

Displace Disc Pathway: starts at lateral pole and proceeds to medial pole unless dentists intervenes

Lateral pole -- middle disc -- medial pole

Trauma

Traumas:

1. BLOW
2. MVA
3. FALLS
4. SPORTS INJURIES

WHIPLASH-MVA

1. Lateral ligament of disc gets damaged
2. Since ER does not pay attention to jaw joint in MVA's
3. Cervical injuries are less image in ER today
4. Request Cervical & TMD imaging if major MVA
5. In one study 22 out 25 TMD's had displace disc after MVA
6. Neck joints are same kind joint as in TMD

BLOWS-SPORT INJURIES:

1. Sports injuries can causes sudden acceleration deaccleration of TMD
2. Tearing of lateral ligament of disc of TMD
3. Request imaging if limited opening or severe pain in TMD
4. Record any symptoms TMD within months of Blow-Fall
5. Blows to jaw typically damage the opposite TMD
6. When mandible is not fracture, then maybe breaking TMD or major tearing lateral ligament

Sports-Related Injuries & TMD

1. 11-18% all sports-related injuries were maxillofacial injuries
2. 44-99% of TMD problems are caused by trauma
3. Risk of sport-related female basketball injury rate = 7.5%
4. 600,000 sports related visits to ER for craniofacial injuries

HEAD & NECK PAIN

Neck Pain: Neighboring Pains:

1. Two types contraction:
   1. Muscle bracing: brace jaw muscles to contract neck muscles
   2. Muscle guarding: Pain causes muscles to protect & guard
   3. 3 layers neck muscles (outside, intermediate, intercostal)
2. Added to muscle contraction:
   1. head movement
   2. muscle tension
   3. work posture
   4. muscle brace
   5. trigger points
   6. weight head or shoulders
   7. posture
   8. shrugging
3. Cervical muscle bracing stimulates jaw clenching, jaw clenching contracts neck muscles

Head Pain: Neighboring Pains:

1. Added muscle contraction due headache
   1. Muscle bracing
   2. Muscle guarding
2. Primary Types HA:
   1. Tension Headaches
   2. Migraines
3. Migraine Pain: sources inflammation
   1. Chewing muscles & joints
   2. Neck muscles & joints
   3. Special organs: ears, nose, sinus, mouth
   4. Virus & Bacteria
   5. Allergies, chemical sensitivities, hypermobility
4. Tension Headache
   1. Stress sets off biochemical pathway: i) cortisol, ii) adrenalin, iii) tension
   2. Stress causes static muscle contraction of our favorite muscle
   3. Pathway: Stress-sympathetic system-temple contraction-lactic acid buildup-inflammation-pain
   4. Tension headache pain is mostly felt in temples
   5. Temple muscle is chewing muscle
   6. 48% women & 38% men have tension HA

Pain System Escalation

1. Increasing Pain signals:
   1. Trauma Injury-Muscle bracing protect joint
   2. Grinding/clenching
   3. Anxiety wires to pain system
   4. Normal Jaw Joint function
   5. Decrease in pain inhibitory system
   6. Change in pain neurotransmitters
   7. Other Biochemical & physiological changes
2. Pain system changes:
   1. length each pain,
   2. intensity pain,
   3. pain from nonpainful stimulus,
   4. wider area pain,
   5. perception pain
3. Poor health habits decrease chance of healing; thus, a likely perpetuation of pain
4. Pain itself causes increase in muscle contraction in certain muscle groups (back, neck, head, jaw)

Open Lock

1. True subluxation TMD
2. Condyle comes out of the socket
3. Causes microtearing lateral ligament w/ each open lock
4. Cause macrotearing if you try force it closed
5. Only 2% of 6% population can even accomplish open lock, hypermobility
6. Requires: a) anterior slope eminence, b) completely displaced disc
7. Stretching then tearing sets up progressive tearing lateral ligament
8. Severely torn lateral ligament causes complete displace disc
9. Open lock tear adds to grind/clench-tension muscle-Trauma tearing-Neighoring pains

Dual Bite

1. Difference between jaw joint bite and tooth bite
   1. Teeth control muscles to protect teeth
   2. Jaw joint wants power control muscles to full seat joint-relax muscles
2. Definitions:
   1. Tooth bite is maximum interdigitation teeth
   2. Jaw joint bite is fully seated condyles in fossa
3. Control of chewing muscles = “muscle guarding”
   1. Teeth controll muscles to go into tooth proctected bite
   2. Jaw joint tries order muscles to allow fully seated condyles
   3. There are teeth in way to full seat condyles
   4. So conflict erupts between muscle controlls
   5. This muscle guarding by both controllers increases muscle inflammation
4. Muscle overuse or over contraction contributors
   1. Joint laxity = hypermobility = dual bite
   2. Tooth position does not allow full seat joint
5. Orthotic allows full seat jaw joint w/o teeth interfering w/ the jaw joint need fully seat
6. Who has dual bite?
   1. 85 % no dual bite
   2. 10 % small dual bite
   3. 5% moderate dual bite
7. Great difference Dual Bite, the greater muscle activity

Interferences/Occlusal issues

1. Interferences are contact of teeth by sides of cusps that interfere w/ cusp/fossa contact
2. Interferences activate more muscle activity to try to avoid them
3. Interferences are not powerful enough by themselves to cause much muscle/joint damage
4. Grinding/clenching is power behind damage attributed to an interference
5. Disclusion of posterior teeth by anterior guidance reduces activity of Temporalis & Masseter, 1983 J Pros