Parafunction, TMD & Occlusal Trauma MCQ

Bruxism, clenching, and other parafunctional habits load teeth and joints beyond physiologic limits. Occlusal trauma (primary in healthy periodontium under excessive force; secondary in reduced periodontium under normal force) produces widened PDL, tooth mobility, fremitus, and pulpal symptoms. TMD splits into muscular (myofascial) and intra-articular components (disc displacement with/without reduction; degenerative OA; RA). Wilkes staging describes the progression of internal derangement. Splint therapy uses a full-coverage stabilization splint for most cases, with anterior-only platforms (NTI, Lucia jig) in selected scenarios.

Bruxism and Other Parafunctional Habits

• BRUXISM is parafunctional clenching or grinding of teeth; SLEEP BRUXISM is sympathetic-driven rhythmic masticatory muscle activity (RMMA) during arousals, often associated with sleep-disordered breathing; AWAKE BRUXISM is more commonly clenching tied to stress and concentration.
• Recognized contributors include sympathetic arousal, sleep apnea, anxiety, caffeine and nicotine, alcohol, and certain medications (SSRIs and SNRIs are recognized bruxism inducers; methamphetamine is another).
• Other parafunctional habits include thumb sucking (in children; produces anterior open bite + proclined uppers + narrow arch), tongue thrusting, lip biting, nail biting, and pen chewing.
• Bruxism diagnosis is clinical: history (partner report of grinding, morning jaw fatigue, headache), examination (wear facets matching opposing teeth, masseter hypertrophy, tongue scalloping), and sometimes polysomnography in selected cases.

Wear Pattern Differential

• ATTRITION: tooth-to-tooth wear; produces flat, shiny, matched wear facets on opposing teeth; classic finding in bruxism.
• ABRASION: wear from an external object; the classic example is toothbrush abrasion at the cervical (V-shaped or U-shaped notches at the CEJ from an aggressive horizontal scrubbing technique).
• EROSION: chemical (acid) wear; produces cupped or dished occlusal surfaces, smooth-shiny enamel loss, and characteristic patterns by source (GERD: palatal of upper teeth; bulimia: same pattern; sports drinks/soda: occlusal cupping + buccal; citrus + lemon juice: anterior).
• ABFRACTION: cervical wedge-shaped lesions theorized to arise from flexure of the tooth under occlusal load; the role of occlusal force vs toothbrush abrasion + erosion in producing these lesions is debated, and the term is used cautiously.

Primary vs Secondary Occlusal Trauma

• OCCLUSAL TRAUMA is injury to the periodontium from excessive occlusal force; it produces widened PDL on radiographs, tooth mobility, fremitus (vibration on closing), and sometimes pulpal sensitivity (without infection).
• PRIMARY occlusal trauma is HEALTHY periodontium under EXCESSIVE force (e.g., a high crown, bruxism on a healthy tooth); it is reversible when force is reduced.
• SECONDARY occlusal trauma is REDUCED (periodontitis-attached) periodontium under NORMAL force; the diminished attachment cannot absorb routine occlusal load; treatment focuses on the underlying periodontitis with force reduction.
• Occlusal trauma DOES NOT cause periodontitis by itself; it is a co-destructive factor that aggravates an existing periodontitis (without infection it produces only widened PDL + mobility, not attachment loss).

TMD: Muscular vs Intra-Articular; Wilkes Staging

• TMD (temporomandibular disorder) includes MUSCULAR (myofascial pain; the most common form) and INTRA-ARTICULAR components (disc displacement with/without reduction; degenerative OA; RA).
• MYOFASCIAL TMD: diffuse muscle tenderness on palpation, jaw soreness, reproducible pain on muscle loading; often bilateral; conservative care first.
• INTRA-ARTICULAR TMD: clicking (disc displacement with reduction), closed lock (disc displacement without reduction), crepitus (OA), or systemic involvement (RA).
• WILKES STAGING (internal derangement progression): Stage I painless click and reciprocal click; Stage II disc displacement with reduction + intermittent locking; Stage III chronic closed lock with limited opening; Stage IV bony changes + chronic pain; Stage V end-stage OA with disc perforation and crepitus.

Splint Therapy

• Stabilization splint (full-arch HARD ACRYLIC; maxillary is most common): full-coverage occlusal appliance that distributes occlusal load, provides centric stops at the new position, and disoccludes posteriors in eccentric movement; used for sleep bruxism, myofascial TMD, and protection during high-VDO provisional periods.
• Anterior bite plane (e.g., NTI-tss; Lucia jig): an anterior-only appliance that disengages the posterior teeth, deprogramming masticatory muscles in the short term; useful for acute myofascial pain or diagnostic CR registration; LONG-TERM full-time wear risks posterior overeruption and anterior intrusion, so it is used short-term or part-time.
• Soft (cushion) splints are inexpensive but compressible; they can encourage muscle activity in some patients and are usually reserved for short-term protection (e.g., athletic mouthguards).
• Splints must be adjusted at delivery (equal-pressure centric stops + canine guidance in lateral + anterior guidance in protrusion) and re-evaluated at follow-up.

Fremitus, Mobility, and the TMD Pain Ladder

• FREMITUS is the palpable vibration of a tooth on closing or excursion; it indicates excessive occlusal force on that tooth and is detected by placing a fingertip on the labial surface during closure.
• MOBILITY is measured by attempting to displace the tooth between two instrument handles (Miller classification: Class 0 = physiologic; I = <1 mm horizontal; II = >1 mm horizontal; III = vertical or rotational mobility).
• TMD pain management ladder (conservative first): patient education + soft diet + jaw rest + heat/ice + jaw stretching + NSAIDs → occlusal appliance (stabilization splint) + physical therapy + relaxation techniques → low-dose tricyclic antidepressant (amitriptyline) for chronic pain → intra-articular injection or specialist referral → surgery for refractory severe cases.
• Persistent severe TMD that fails conservative care should be referred for further TMD/orofacial pain specialist management; advanced imaging (MRI for soft tissue/disc; CT or CBCT for bony changes) is selected on findings.