TMD/CMD, Occlusion & Orthotic Treatment Lecture Notes

This set of vocabulary flashcards covers the clinical definitions, evidence-based findings on occlusion causality, and the various types and mechanisms of orthotic splints used in treating Temporomandibular Disorders (TMD).

Temporomandibular disorders (TMD)

A heterogeneous group of musculoskeletal conditions affecting the TMJ, the masticatory muscles, and surrounding structures, with a prevalence of roughly $31\%$ in adults and $11\%$ in children.

Diagnostic Criteria for Temporomandibular Disorders (DC/TMD)

The modern gold-standard classification system that divides TMD into two major subtypes: Myogenous (muscular) and Arthrogenous (joint).

Myogenous TMD

A subtype of TMD involving the masticatory muscles, presenting as myalgia, myofascial pain, or trismus, most commonly in the masseter and temporalis.

Arthrogenous TMD

A joint-related subtype of TMD that includes conditions such as disc displacement (with or without reduction), arthralgia, and degenerative joint disease.

Gnathological paradigm

A historical model suggesting occlusal factors like malocclusion and dental interferences were primary etiological agents for TMD, driving treatments like occlusal equilibration and irreversible modifications.

Manfredini et al. (2017) Review

A landmark systematic review of 25 studies that concluded dental occlusion has no demonstrated causal role in the vast majority of TMD cases, marking 'the end of an era' for the gnathological paradigm.

Orthodontics-neutral

A conclusion from Manfredini et al. (2016) stating that fixed appliances, clear aligners, and functional appliances neither predictably improve nor worsen TMD status at a population level.

Hard stabilization splint (HSS)

Also known as a Michigan splint, this full-arch hard acrylic appliance provides even contacts in centric relation and is used for myogenous and arthrogenous TMD and bruxism protection.

Anterior repositioning splint (ARS)

An appliance designed to protrude the mandible to recapture the disc, primarily used for disc displacement with reduction.

NTI-tss

A small anterior contact-only device used for bruxism-related TMD and migraine prevention.

Non-occluding (palatal) splint

An appliance with no occlusal contact surface used as an active placebo or control in randomized controlled trials (RCTs).

Multimodal therapy

A treatment approach combining a hard stabilization splint with counseling or self-management, which consistently outperforms any single intervention alone.

Mechanical deloading

A mechanism where splints help by increasing vertical dimension, which reduces direct loading on TMJ structures and decreases muscle compression forces.

Cognitive awareness

A therapeutic mechanism of occlusal appliances where the device increases proprioceptive awareness of jaw clenching and parafunctional habits, interrupting them through conscious feedback.

Regression to the mean

The tendency of TMD to undergo natural remission over time, particularly in mild-to-moderate presentations, narrowing the gap between splint therapy and no treatment.

Orthognathic surgery (TMD effect)

A procedure that can reduce TMD symptoms in pre-operatively symptomatic patients but may create new symptoms in a small proportion of previously asymptomatic patients.