Home · Glossary · September 12, 2026 · 18 min

Orofacial myology & myofunctional therapy glossary: the complete A-to-Z reference

The field of myofunctional therapy uses a lot of unfamiliar vocabulary. The terms come from anatomy, dentistry, sleep medicine, speech-language pathology, and orthodontics, and they don't always translate cleanly into everyday English. This glossary collects every myofunctional-therapy term you might encounter — on a provider's website, in a referral note from your dentist or ENT, in a sleep study report, or in a discussion with your insurance company.

By Gina Sabbak, RDH — Myofunctional Therapist · Last reviewed: 2026-09-12

A

Adenoid

A mass of lymphatic tissue at the back of the nasal cavity, behind the nose and above the soft palate. Adenoids are part of the immune system and are largest in young children, typically shrinking by adolescence. When enlarged, they can partially block the nasal airway, forcing a child to breathe through their mouth. Chronic mouth breathing in childhood is one of the most common reasons families are referred to a myofunctional therapist. Adenoid removal (adenoidectomy) is sometimes recommended; even after surgery, the habit of mouth breathing can persist, which is where myofunctional therapy helps — retraining the tongue, lips, and jaw to default to nasal breathing and closed-mouth rest posture.

Adult palatal expansion

A dental procedure that widens the upper jaw (maxilla) in adults. Traditional expansion worked only in children because the midpalatal suture fused around puberty; modern surgically- or device-assisted techniques (MSE, DOME, SARPE) can split or stretch the suture in adults. A narrow upper jaw reduces nasal volume and contributes to obstructive sleep apnea. Research published in 2023 showed DOME (distraction osteogenesis maxillary expansion) effectively improved AHI in adult OSA patients. Myofunctional therapy typically comes before and after expansion — before to prepare the soft tissues, after to stabilize the new shape and integrate the changes into function. See the adult expander guide on our site for the full protocol.

Airway

The passage through which air moves during breathing. It includes the nasal cavity, oral cavity, pharynx (throat), larynx (voice box), trachea (windpipe), bronchi, and lungs. Myofunctional therapists focus on the upper airway — nose, mouth, throat — because the muscle tone and posture in this region determines whether the airway stays open during sleep and at rest. When the upper airway collapses or narrows during sleep, the result is snoring or obstructive sleep apnea.

Apnea (and Apnea-Hypopnea Index, AHI)

Apnea is a complete pause in breathing lasting at least 10 seconds during sleep. Hypopnea is a partial reduction in airflow (≥30%) with associated oxygen desaturation or arousal. The Apnea-Hypopnea Index (AHI) is the number of apneas plus hypopneas per hour of sleep, measured during a sleep study. AHI is how sleep medicine grades the severity of obstructive sleep apnea: mild (5-15), moderate (15-30), severe (>30). Myofunctional therapy has been shown in a 2015 systematic review and meta-analysis (Camacho et al.) to reduce AHI by approximately 50% in adults with mild-to-moderate OSA, with the effect most pronounced in patients who use it as adjunctive therapy alongside CPAP or oral appliance therapy.

Airway, collapsible segment of

The portion of the upper airway that has no bony or cartilaginous support — primarily the soft palate, the base of the tongue, and the lateral pharyngeal walls. During sleep, muscle tone drops, and this segment can collapse inward. Myofunctional therapy strengthens the muscles that hold this segment open — particularly the tongue and the soft palate.

B

Bicuspid (also premolar)

The teeth between the canines and the molars. Adults have eight bicuspids. They are transition teeth used for both tearing and grinding. From a myofunctional standpoint, the bicuspids matter because they erupt in childhood — around age 10-12 — and their position is influenced by tongue posture and resting pressure. A tongue that rests low and forward, or that pushes against the front teeth, can affect how these teeth come in.

Bolus

The mass of food (or liquid) that has been chewed and is ready to be swallowed. A normal swallow moves the bolus from the front of the mouth, presses it against the hard palate with the tongue, and sends it down the throat. A tongue thrust swallow (atypical swallow) is when the tongue pushes forward against or between the front teeth instead of pressing against the palate. This pattern is one of the things myofunctional therapy works to correct, because it can contribute to open bite, spacing, and other dental issues over time.

Bruxism

Grinding, clenching, or gnashing the teeth, usually during sleep but sometimes during waking hours. Bruxism is associated with stress, certain medications, sleep-disordered breathing, and muscle tension in the jaw and face. Myofunctional therapy addresses the muscle-tension component through jaw relaxation, posture work, and lip-seal training. In some patients, treating an underlying sleep-breathing problem (with myofunctional therapy and/or an oral appliance) reduces bruxism significantly.

C

CBCT (Cone Beam Computed Tomography)

A 3D dental imaging scan. CBCT is used to assess the airway, sinus anatomy, jaw position, and tooth-root orientation. Some myofunctional therapists and dentists use CBCT images to evaluate the airway cross-sectional area as part of a comprehensive workup, particularly when sleep-disordered breathing or expansion is part of the clinical picture.

Chewing pattern

The way a person moves their jaw when eating. A typical adult pattern is bilateral — chewing on both sides, alternating. Some patients develop unilateral chewing (always one side) due to dental work, missing teeth, TMJ discomfort, or habit. Myofunctional therapy can include exercises to retrain a balanced bilateral chewing pattern.

CPAP (Continuous Positive Airway Pressure)

The gold-standard medical treatment for moderate-to-severe obstructive sleep apnea. A CPAP machine delivers pressurized air through a mask, keeping the airway splinted open during sleep. Many patients struggle with CPAP adherence (mask discomfort, claustrophobia, dry mouth, partner disturbance). Myofunctional therapy is the most evidence-supported adjunctive treatment for CPAP users who want to reduce pressure settings, who can't tolerate CPAP, or who want a non-device treatment option.

Crowding (dental crowding)

Insufficient space in the dental arch for all the teeth to align properly. Crowding can be genetic (small jaw, large teeth) or environmental (mouth breathing, low tongue posture, thumb-sucking that persists past age 4-5). Myofunctional therapy addresses the environmental contributors; orthodontic treatment (braces, aligners, expansion) addresses the actual tooth position. The two work well together.

D

Daytime fatigue

Persistent tiredness during waking hours, despite apparently adequate time in bed. In myofunctional-therapy referrals, daytime fatigue is usually a downstream symptom of sleep-disordered breathing — the patient's sleep is fragmented by apneas, hypopneas, or micro-arousals, even if they don't fully wake up. Many patients come to myofunctional therapy for fatigue before they ever get a sleep study; the myofunctional evaluation is sometimes the first place the underlying airway problem is flagged.

Diastema

A gap between two teeth, most commonly the upper front teeth (central incisors). A persistent diastema in adults can result from a thick labial frenum, tongue thrust, periodontal disease, or simply the natural shape of the dental arch. Myofunctional therapy is sometimes part of pre-orthodontic or post-orthodontic care for diastema closure, particularly when a tongue-thrust swallow pattern is contributing.

DOME (Distraction Osteogenesis Maxillary Expansion)

A surgical-orthodontic technique for widening the adult maxilla. A surgeon makes controlled bone cuts, and a patient-operated expander device gradually separates the two halves of the upper jaw over weeks. A 2023 study showed significant AHI reduction in adult OSA patients treated with DOME. Myofunctional therapy is commonly recommended both before and after DOME — before to prepare the soft tissues, after to maintain the expansion and integrate it into functional patterns.

E

Etiology

The cause or origin of a condition. In myofunctional therapy, identifying the etiology of a tongue thrust, mouth-breathing habit, or atypical swallow is essential to fixing it. A common example: a child with a tongue thrust caused by persistent thumb-sucking needs the thumb-sucking addressed before the swallow pattern can be retrained successfully. Another: an adult with nighttime mouth breathing who has undiagnosed sleep apnea needs that evaluated before the breathing pattern can be sustainably changed.

F

Frenectomy / Frenotomy

Surgical procedures to release a restrictive frenulum (the small fold of tissue under the tongue, under the upper lip, or inside the cheek). A lingual frenectomy addresses ankyloglossia (tongue-tie); a labial frenectomy addresses a restrictive upper-lip tie. The procedure itself is brief — often done with a laser in a single office visit. Myofunctional therapy is a critical part of the process before the procedure (preparing the tongue to achieve its full range of motion once released) and after (re-establishing proper tongue posture, swallowing, and speech patterns in the newly-mobile tongue).

Frenulum

The thin band of connective tissue that connects the underside of the tongue to the floor of the mouth. When this band is unusually short, thick, or tight, it restricts tongue movement — the condition called tongue-tie or ankyloglossia. A normal frenulum allows the tongue tip to reach the roof of the mouth, lick the upper lip, sweep the back of the lower front teeth, and protrude past the lower lip. Many children and adults have mildly restrictive frenula that don't cause problems; a smaller subset have restriction significant enough to affect feeding, speech, breathing, or sleep.

G

Genioglossus

The large fan-shaped muscle that makes up most of the bulk of the tongue. It originates on the inside of the chin and inserts along the underside of the tongue from tip to back. The genioglossus is the primary muscle that keeps the tongue forward in the mouth during sleep; when its tone drops (during deep sleep, alcohol consumption, sedation), the tongue can fall back and obstruct the airway. Exercises that strengthen the genioglossus are a core part of myofunctional therapy for sleep-disordered breathing.

Gingivitis

Inflammation of the gums, typically caused by plaque accumulation. While gingivitis is a periodontal diagnosis rather than a myofunctional one, mouth breathing (particularly at night) dries the gums and increases gingivitis risk. Children with chronic mouth breathing often present with inflamed, reddened, swollen gums — particularly the upper front teeth — that doesn't fully respond to brushing and flossing alone until the breathing pattern is corrected.

H

Habit elimination

A core myofunctional therapy service for children (and sometimes adults) working to stop non-nutritive sucking habits — thumb-sucking, finger-sucking, pacifier use past the typical age (around 4-5), lip-biting, nail-biting, or tongue-sucking. These habits can affect dental development, speech, and swallowing patterns. Myofunctional therapy approaches habit elimination with positive reinforcement rather than shaming or punishment; the approach varies by age and motivation.

I

Interdisciplinary care

Coordinated treatment involving multiple providers from different specialties. In myofunctional therapy, the typical care team includes a myofunctional therapist (often a dental hygienist or speech-language pathologist), a referring dentist or orthodontist, an ENT or allergist (when airway or adenoid issues are present), a sleep medicine physician (when sleep apnea is suspected), a bodyworker or physical therapist (when TMJ, neck, or postural issues are involved), and sometimes a lactation consultant (for infant feeding). Good myofunctional therapy is rarely done in isolation — it's part of a network.

L

Lip incompetence

The resting posture where the lips are apart at rest, requiring mouth breathing (or at least allowing it). Lip incompetence in children is one of the most visible signs of an underlying breathing or tongue-posture problem. Myofunctional therapy addresses lip competence through lip-seal exercises — short, frequent practice sessions throughout the day aimed at training the lips to default to a closed resting posture.

Lip-tie

A restrictive labial frenulum — the band of tissue connecting the upper lip to the gum above the front teeth. A restrictive upper-lip tie can prevent the upper lip from flanging out properly during breastfeeding (in infants) and can contribute to a gap between the upper front teeth (diastema). Whether lip-ties need to be released is more controversial than tongue-ties; many clinicians treat lip-ties conservatively unless they're clearly causing functional problems.

M

Malocclusion

A misalignment of the upper and lower teeth when the jaw is closed. Common malocclusions include overbite, underbite, crossbite, open bite, and crowding. Some malocclusions are largely genetic; others are functional — caused or worsened by mouth breathing, low tongue posture, atypical swallow, or thumb-sucking. Orthodontic treatment (braces, aligners, expansion) repositions the teeth; myofunctional therapy addresses the muscle and habit contributors that can cause orthodontic relapse after treatment.

Mandible

The lower jaw. The mandible is the only movable bone of the skull and articulates with the temporal bone at the TMJ. In myofunctional therapy, the resting position of the mandible — slightly open at rest, with lips closed, teeth slightly apart, and tongue on the palate — is a core postural goal.

Mouth breathing

Habitual breathing through the mouth instead of the nose, during the day, at night, or both. Mouth breathing in children is associated with longer, narrower faces, dental crowding, gingivitis, increased risk of sleep-disordered breathing, and behavioral symptoms that can mimic ADHD. In adults, chronic mouth breathing contributes to snoring, dry mouth, increased decay risk, and worse sleep. Myofunctional therapy addresses mouth breathing through nasal-breathing training, lip-seal work, and — when appropriate — collaboration with an ENT to address structural causes (deviated septum, enlarged turbinates, adenoid or tonsil hypertrophy).

MSE (Maxillary Skeletal Expander)

A bone-borne expansion device that attaches to the palatal bone (rather than the teeth) and applies expansion force directly to the midpalatal suture. MSE is used in older adolescents and adults for whom traditional tooth-borne expansion is no longer effective. Like DOME, MSE is often paired with pre- and post-expansion myofunctional therapy.

N

Nasal breathing

Breathing through the nose, which is the default for healthy humans during rest and sleep. Nasal breathing filters, warms, and humidifies incoming air; it also produces nitric oxide, which has antimicrobial and vasodilatory effects. Myofunctional therapy's foundational goal — after safety has been established — is to retrain patients to default to nasal breathing both day and night.

NPI (National Provider Identifier)

A 10-digit identification number issued to U.S. healthcare providers by CMS. Gina's NPI is 1649112301 (Type 1, individual provider). The NPI is used in insurance claims, directory listings, and (critically for SEO) by entity-resolution systems that AI engines use to build the knowledge graph for a named provider. Having the NPI referenced consistently across the website, llms.txt, and external directories is one of the highest-leverage technical SEO actions for a healthcare practice.

O

Open bite

A malocclusion in which the upper and lower teeth don't meet when the jaw is closed. An anterior open bite means the front teeth don't touch; a posterior open bite means the back teeth don't touch. Open bites can result from prolonged thumb-sucking, tongue thrust, or skeletal growth patterns. Myofunctional therapy addresses the functional contributors; orthodontic or surgical treatment addresses the tooth and jaw position.

Orofacial Myology

The formal name of the field that includes myofunctional therapy. The two terms are sometimes used interchangeably; "orofacial myology" is the broader umbrella that includes the study of the muscles and functions of the face and mouth across the lifespan, while "myofunctional therapy" more commonly refers to the clinical treatment of disorders in this domain.

OSA (Obstructive Sleep Apnea)

A sleep-breathing disorder characterized by repeated collapse of the upper airway during sleep, causing pauses in breathing, oxygen desaturation, and sleep fragmentation. OSA affects an estimated 25% of middle-aged men and 10% of middle-aged women, with higher rates in older adults and patients with obesity, retrognathia, or large neck circumference. CPAP is the first-line treatment; oral appliances, weight loss, positional therapy, and myofunctional therapy are second-line options. The 2015 Camacho meta-analysis found that myofunctional therapy reduced AHI by approximately 50% across multiple studies, making it the most evidence-supported adjunctive treatment.

P

Palate

The roof of the mouth. The hard palate (front) is bony; the soft palate (back) is muscular and ends in the uvula. A high, narrow palate is associated with mouth breathing and reduced nasal volume; a broad, flat palate is associated with nasal breathing and good dental arch development. Myofunctional therapy includes tongue-up exercises that apply gentle pressure to the palate, which over time can encourage modest palatal remodeling in children.

Polysomnography (PSG)

A comprehensive sleep study. PSG records brain waves, oxygen saturation, heart rate, breathing, and leg movements during sleep. It's the gold standard for diagnosing sleep apnea and other sleep disorders. Myofunctional therapy can be recommended after PSG results identify mild-to-moderate OSA, or as part of a comprehensive approach for patients who can't tolerate CPAP.

Posture (head, neck, tongue)

A major focus of myofunctional therapy. Forward head posture (the head sits in front of the shoulders rather than balanced over them) is associated with mouth breathing, low tongue posture, and reduced airway space. The myofunctional therapy approach to posture includes jaw-and-neck alignment work, ergonomic awareness, and (often) collaboration with a physical therapist or chiropractor for body-level postural issues.

R

Rest posture (oral rest posture)

The default position of the tongue, teeth, and lips when not speaking, eating, or swallowing. The ideal oral rest posture: lips closed, teeth slightly apart (or lightly together), tongue tip resting gently on the spot behind the upper front teeth (the palatal spot or incisive papilla), and breathing through the nose. Myofunctional therapy trains this as the default; it's the foundation of everything else.

S

Sleep-disordered breathing (SDB)

An umbrella term covering everything from primary snoring (no apneas, no oxygen desaturation) to severe obstructive sleep apnea. SDB in children looks different from SDB in adults: children rarely present with classic adult OSA symptoms (witnessed apneas, daytime sleepiness); instead, they may present with hyperactivity, behavioral problems, poor school performance, bedwetting, restless sleep, night sweats, snoring, or mouth breathing. Myofunctional therapy can help with mild-to-moderate SDB in both populations.

Snoring

The sound produced when air flows past relaxed tissues in the throat during sleep, causing the tissues to vibrate. Snoring is common — about 40% of adult men and 20% of adult women snore regularly — and ranges from benign to a sign of underlying OSA. Myofunctional therapy reduces snoring by strengthening the tongue and soft-palate muscles, training nasal breathing, and improving tongue posture during sleep.

T

Thumb-sucking

A non-nutritive sucking habit most common in children under 4. Most children stop on their own between ages 4 and 6; thumb-sucking that persists past age 5-6 can affect dental development (anterior open bite, posterior crossbite, V-shaped palate) and speech (particularly /s/, /z/, /t/, /d/ sounds). Myofunctional therapy approaches habit elimination with positive reinforcement, calendar tracking, and (when needed) a custom habit appliance.

TMJ / TMD (Temporomandibular Joint / Disorder)

The TMJ is the hinge connecting the mandible to the temporal bone of the skull, located just in front of each ear. TMD refers to disorders of this joint and the surrounding muscles — clicking, popping, locking, pain, limited opening. Some TMD symptoms are driven by muscle tension, clenching, or poor oral rest posture, and respond to myofunctional therapy. Other TMD symptoms are joint-internal (disc displacement, arthritis) and need a different approach. A good myofunctional therapist will refer to a TMJ specialist when the problem is joint-internal rather than muscular.

Tongue thrust

A swallowing pattern in which the tongue pushes forward against or between the front teeth instead of pressing against the hard palate. Tongue thrust can contribute to anterior open bite, spacing between the front teeth, and orthodontic relapse. It's one of the most common reasons patients — particularly children — are referred for myofunctional therapy. Treatment involves retraining both the swallowing pattern and the resting posture of the tongue.

Tongue-tie (ankyloglossia)

A congenital condition in which the lingual frenulum is unusually short, thick, or tight, restricting tongue movement. Severity varies widely. Severe tongue-tie can affect infant breastfeeding, childhood speech, adult sleep-disordered breathing, and swallowing. Treatment involves a release procedure (frenectomy, often done with a laser) plus pre- and post-procedure myofunctional therapy to retrain tongue function in the newly-mobile tongue.

Tonsils

Two masses of lymphatic tissue at the back of the throat (one on each side). Like adenoids, tonsils are part of the immune system and are largest in childhood. Enlarged tonsils can contribute to sleep-disordered breathing in children; tonsillectomy is sometimes recommended. Even after tonsillectomy, the muscle-and-posture work of myofunctional therapy is often needed to fully resolve mouth breathing and snoring.

U

Uvula

The small fleshy extension at the back of the soft palate that hangs above the throat. The uvula can contribute to snoring when it vibrates during sleep. Some patients have an elongated or enlarged uvula that's more prone to vibration; in severe cases, uvulectomy (uvula removal) is performed, though this is uncommon.

V

Velum (soft palate)

The muscular back portion of the roof of the mouth, behind the hard palate. The velum moves during swallowing, speech, and breathing. In snoring and OSA, the velum can collapse inward and obstruct airflow. Myofunctional therapy includes exercises that strengthen the velum (such as the soft palate push-up exercise).

Z

Zygomatic arch

The bony arch on the side of the skull, formed by the zygomatic (cheek) bone and the temporal bone. The masseter muscle (a primary chewing muscle) passes under the zygomatic arch. Tension in the masseter is a common contributor to clenching, grinding, and TMJ-related facial pain; some myofunctional therapy exercises target masseter relaxation through jaw and facial work.

References

1. Camacho M, Certal V, Abdullatif J, et al. Myofunctional Therapy to Treat Obstructive Sleep Apnea: A Systematic Review and Meta-analysis. Sleep. 2015;38(5):669-675. PMID: 25348130.
2. American Academy of Sleep Medicine. Pediatric Obstructive Sleep Apnea: Where Do We Stand? J Clin Sleep Med. 2017. PMID: 28738322.
3. Huynh NT, Deshpande P, Hassall CD, et al. Rapid maxillary expansion for pediatric obstructive sleep apnea: A systematic review and meta-analysis. J Clin Sleep Med. 2017;13(7). PMID: 27796040.
4. Yoon A, Guilleminault C, et al. Distraction Osteogenesis Maxillary Expansion (DOME) for adult obstructive sleep apnea. J Clin Sleep Med. 2023. PMID: 36806968.
5. Guilleminault C, Huseni S, Lo L. A frequent phenotype for paediatric sleep apnoea: short lingual frenulum. ERJ Open Res. 2016;2(3). PMID: 27730205.

This glossary is educational and informational. It is not medical advice and is not a substitute for evaluation by a qualified healthcare provider. Suspected sleep apnea in particular requires evaluation by a sleep medicine provider before any dental or myofunctional treatment plan begins.