Part Four: Oromyofunctional Therapy and Orthodontics

Finally, wrapping up this series with a review on oromyofunctional therapy; thank you for your patience 😊. This article will also serve as an accompanying follow-up and addendum to the OMT section of my tongue tie article that I wrote back in 2020.

1.      Historic Review of OMT

Oromyofunctional therapy (OMT) has exploded in popularity in the last decade. OMT encompasses exercises and techniques that target orofacial muscle dysfunction, improper swallowing patterns, and mouth breathing habits. (Abbooud AlQhtani, 2024; Hou & Meng, 2020). OMT focuses on strengthening the orofacial muscles and promotes nasal breathing and improving the resting posture of the tongue (Leung and Van Noy, 2024) for overall improved stomatognathic function (i.e. breathing, chewing, swallowing and speech).

According to the Academy of Oral Myofunctional Therapy, “Orofacial Myofunctional Therapy is neurological re-education to assist the normalization of the developing, or developed, craniofacial structures and function. This is accomplished through targeted muscle exercises that improve tone, proprioception, and mobility” (Leung and Van Noy, 2024; Shah et al., 2020). Furthermore, OMT aims to address the underlying causes of malocclusion and enhance the stability of orthodontic treatment outcomes by promoting proper muscular function and oral posture.

OMT optimally involves a collaborative effort between dentists (i.e. pediatric dentists and/or orthodontists) as well as speech therapists, dental hygienists, occupational therapists, primary care physicians, and finally oral surgeons and/or ENTs when indicated. OMT encompasses a function-based assessment and approach to deliver comprehensive care. To my surprise, OMT has a substantial history that surpasses 100 years. OMT and proper tongue positioning in the oral cavity have been described since as far back as 1918(!) when Alfred Paul Rogers advocated OMT to improve mandibular growth, nasal breathing and facial appearance (Leung and Van Noy, 2024; Zaghi et al., 2010; Camacho et al., 2015; Rogers, 1918). Furthermore, Guimaraes (1999) had proposed utilizing OMT as an adjunct to OSA treatment since the 1990s.

OMT has emerged as a critical intervention in pediatric dentistry, particularly in addressing sleep disordered breathing (SDB) and non-nutritive sucking habits (NNSH), and their impact on growth and development (Leung and Van Noy, 2024). Early intervention is key to prevention and to guiding growth. The jaw is 50% developed by age 6 and 90% by age 12 (Leung and Van Noy, 2024; Page, 2003). Therapeutic interventions improve neuromuscular function, strengthen muscles, and improve orofacial muscular contraction and sensitivity (Liu et al., 2023). Leung and Van Noy (2024) recommend pediatric exams to investigate and document current non-nutritive sucking habits such as finger sucking or pacifier use, SDB symptoms including snoring, grinding, apneic episodes or mouth breathing, orthodontic relationships and habits. Examination may further reveal other signs such as wear facets, tongue thrust, palatal abnormalities, malocclusion, deep bite, anterior open bite, narrow airway, or tonsillar hypertrophy. The authors recommend correlating these findings with the FAIREST-6 assessment (Oh et al., 2021) or the Pediatric Airway Assessment in the American Academy of Pediatric Dentistry Reference Manual (2023).

Assessment of Need of Myofunctional Therapy

The biggest challenge for OMT that I perceive today, after over 100 years of its inception, is the lack of standardized regimens across practitioners nor abundant peer-reviewed randomized controlled trials that may support structured protocols. Liu et al. (2023) and Abbooud AlQhtani (2024) relatedly express the variety in study methodologies and outcome measures. Liu et al. (2023) also mention that there are no systematic evaluations or meta-analyses of the effects of OMT on facial morphology in children with SDB.

2.      So, what are the actual OMT exercises?

OMT comprises isotonic and isometric exercises that target oral (i.e. lips, tongue) and oropharyngeal structures (i.e. soft palate, lateral pharyngeal walls) (Camacho et al. 2015; Guilleminault et al., 2013; Guimaraes et al., 2009). More specifically, for soft palate exercises, patients pronounce oral vowel sounds either continuously (isometric exercises) or intermittently (isotonic exercises) (Guimaraes et al., 2009). Meanwhile, tongue exercises might include moving the tongue along the roof of the mouth and side (lateral) surfaces of the teeth/cheeks, positioning the tongue tip against the anterior aspect of the hard palate, pressing/suctioning the entire tongue against the hard and soft palate, and forcing the tongue onto the floor of the mouth (Guimaraes et al., 2009). Lastly, facial exercises address the lips (i.e., contraction and relaxation of the orbicularis oris muscles), buccinators (i.e., suction movements and application of intraoral finger pressure against the buccinator muscles, which are cheek muscles), and jaw muscles (i.e., via lateral jaw movements) (Guimaraes et al., 2009). In addition, a patient’s stomatognathic functions are addressed by instructing them to inhale nasally and to exhale orally, first without and then with balloon inflation, as well as performing specific swallowing and chewing exercises. As an aside, I plan to explore broader whole-body topics more in my next article so stay tuned for that!

Meanwhile, the OMT protocol derived from Habumugisha et al. (2022) includes the following exercises:

1.      Lip sealing training with a lip trainer whose tension was 250 g for 10 minutes, three times per day;

2.      Tongue flipping training (the tip of the tongue bouncing at the palate strongly), 100 times per day;

3.      Chewing gum training (spreading out chewing gum at the palate),15 times per day;

4.      Swallowing training (pushing 15 ml water on the tip of their tongue up against the hard palate and swallowing with lips closed), 15 times per day. 

Source: TMJ Sleep and Breathe Center

I wanted to mention that resting tongue posture practice is not overtly reviewed in the aforementioned exercises. From the lens of an orthodontist, improper resting tongue posture is a strong underlying source of malocclusions. I tell my patients not to rest their tongues on their teeth and that they can envision carrying out the sound of the letter "n" with their tongue resting on the roof of their mouth instead. My four-part resting oral physiology formula I share with my patients is: (1) tongue resting on the roof of the mouth, (2) teeth are separated at rest, (3) lips are sealed, and (4) breath from the nose. They say it takes about a month to make or break a habit; try this one at home! And feel free to ask me my thoughts on mouth tape while we're at it.

Svensson et al. (2003) described the mechanism of OMT to relate to central nervous system plasticity of the corticomotor control of tongue musculature, which was induced by tongue-task training. Therefore, patients could learn and sustain new tongue, lip and jaw patterns in the long term. In summary, OMT has a range of benefits, wherein studies show improvements in orthodontic treatment outcomes and satisfaction, sleep disordered breathing (SDB), habit mitigation, and prevention of temporomandibular disorders (TMD). Oropharyngeal exercises seem to effectively modify tongue tone, reduce SDB symptoms and mouth breathing, as well as increase oxygen saturation, and thus may play a role in the treatment of SDB (Evangelisti et al., 2017).

3.      Orthodontic Benefits in Combination with OMT

OMT as an adjunct to orthodontic treatment has shown a positive impact on treatment outcomes, including improved occlusal stability, enhanced facial esthetics, and increased satisfaction (Abbooud AlQhtani, 2024; Miller, 2020).

In studies performed by Smithpeter and Covell Jr (2010), as well as Benkert (1997), OMT in conjunction with orthodontic treatment was highly effective in maintaining the closure of anterior open bites and overjet reduction compared with orthodontic treatment alone. Smithpeter and Covell Jr (2010) presented a key finding that relapse was significantly less for patients who were treated with a combination of orthodontics and OMT. Miller (2020) was also able to successfully treat a patient’s third(!) orthodontic attempt to close an anterior open bite, once the patient’s treatment was in conjunction with a 6-month OMT program. Previous treatments, which had included double jaw surgery, had relapsed. Miller (2020) postulated that the patient’s tongue thrust during rest and swallowing was the cause of the patient’s repeated relapse. Smithpeter and Covell Jr (2010), via reporting Brandt’s interview with Dr. Proffit on OMT (1977), relatedly suggested that tongue’s resting posture could be more important than swallow patterns in dental open-bite patients.

Miller (2020) Case Report Open Bite Correction

Furthermore, Melson (1979) had witnessed an increased observation of distal occlusion (Class II), extreme maxillary overjet, and anterior open bite with the presence of a tongue thrust/teeth apart swallow pattern. Less than ten years later, a study by Pierce (1988) demonstrated that vertical elevation of the tongue optimizes growth and development of the maxilla. Green’s case report (2013) noted that horizontal maxillary growth and development was witnessed following 30 days of digit sucking habit cessation. Green (2013) additionally recommends referring for OMT prior to orthodontic treatment, such as RPE therapy, if symptomology is so severe that it may impede orthodontic outcomes. Green also recommends sustaining OMT support once the expander is placed, until the expansion is complete. This helps decrease the risk of orthodontic treatment relapse due to the unnatural forces from any digit sucking or other habits in combination with the accompanying low resting tongue posture and swallow patterns that a habit might have perpetuated.

Habumugisha et al. (2022) have also shared several orthodontic improvements with OMT: cephalometric measures of U1-NA, L1-NB angles, and U1-NA, L1-NB linear distances decreased significantly. Clinically, patients’ overjets decreased significantly while overbites increased (in relation to an anterior open bite). The mandible showed significant forward growth in the OMT treatment group. Moreover, pre-therapeutic increased measures of the anterior lower facial height and decreases of the maxillary canine width were corrected after introducing OMT.

Abbooud AlQhtani’s study (2024) revealed a higher percentage of patients achieving harmonious facial profiles in the OMT treatment group, with a positive impact on facial aesthetics. This observation is consistent with previous research suggesting that OMT can improve soft tissue contours and facial balance, leading to more esthetically pleasing outcomes (Carvalho et al., 2010). Liu et al. (2023) specified that short-term (i.e. <2 months) therapies benefit muscle strength, while long-term programs will enable facial structural change. Patients who underwent OMT also reported higher levels of satisfaction than those receiving orthodontic treatment alone. This finding stresses the importance of addressing functional etiologies of orthodontic treatment. By targeting underlying muscle dysfunction and promoting proper oral habits, OMT complements traditional orthodontic approaches and contributes to more comprehensive and holistic treatment outcomes (Mehta et al., 2020).

3.      OMT and Growth and Development, Sleep Disordered Breathing (SDB) and Mouth Breathing Prevention

Several studies that I also reported in my tongue tie article have reported the unfavorable effects on tongue restriction on orofacial growth and development, which increase the propensity of SDB.  Leung and Van Noy (2024) define SDB as not only obstructive sleep apnea (OSA), but also hypoxemia, upper airway resistance, hypoventilation, and central sleep apnea (Foldvary-Schaefer & Waters, 2017). Symptoms associated with SDB include snoring, bruxing, open-mouth breathing, and periods of apnea (airflow cessation). In addition, these symptoms are also associated with less restful sleep and have been related to daytime sleepiness and behavioral disorders (Shah et al., 2021). You can also find much more info on this in my OSA articles 😊Yoon and colleagues (audio) shared that reduced tongue mobility correlated with a smaller ratio between the maxillary intercanine width and the canine-to-canine arch length, which may indicate underdevelopment of the upper jaw. In addition, those with reduced tongue mobility had longer soft tissues at the back of the roof of the mouth. Longer soft palates are also common in patients with OSA/SDB. It’s been postulated that limited tongue movement influences mouth breathing, as well as abnormal swallow patterns, which may further elongate the soft palate. In addition, the longer soft palate might arise from reduced tension holding up the soft palate due to the narrower maxilla.

There are several studies that investigate the influence of OMT on SDB prevention. Camacho et al. (2015) provided a systematic review wherein OMT decreases the apnea-hypopnea index (AHI) by approximately 50% in adults and 62% in children. Both pediatric studies that Camacho and colleagues reviewed used 2007 AASM scoring criteria to define apneas and hypopneas. Guilleminault and colleagues (2013) noted that OMT in combination with adenotonsillectomy and rapid palatal expansion (RPE) effectively cured pediatric patients of their OSA after a four-year follow-up (i.e. AHI scores of 0.5 ± 0.4/hr). Camacho et al. observed an improvement in lowest oxygen saturation by approximately 3–4%, with the meta-analysis of 81 patients. Additionally, they reported that oxygen desaturation index (ODI), which is a related measure, was only reported by Baz et al. (2012), who demonstrated a 36% reduction in this figure. Camacho et al. (2015) witnessed improvements in snoring measurements, both objectively and subjectively, as well. The polysomnography demonstrated a 72.4% reduction in snoring pre- versus post-OMT. Subjective sleepiness also improved post-OMT. There was a decrease in Epworth Sleepiness Scale (ESS) scores for the 93 patients in which it was administered, with a reduction from 14.8 ± 3.5 to 8.2 ± 4.1.

Camacho et al. (2015) did share a few limitations: although there were nine adult studies, pediatric studies were quite limited. At the time of their article, only two articles were published. Additionally, long-term follow-up for more than 6 months were limited. One exception was the study performed by Guilleminault et al. (2013), which followed patients for 4 years, while all of the other studies spanned 2 to 6 months. 

Meanwhile, several years later, Habumugisha et al. (2022) explored the relationship between mouth breathing and OMT in children. Mouth breathing has a complex etiology that the authors report may range from anatomic obstructions such as palatine and pharyngeal tonsil hypertrophy, septal deviation, nasal polyps, nasal turbinate hypertrophy, and allergic rhinitis to harmful oral habits (Zhao et al., 2021; Paw et al., 2020; Mohamed et al., 2022). That said, mouth breathers with no obstructive etiological factors are called functional mouth breathers (de Barbiero et al., 2008; Costa et al., 2017).

Functional mouth breathing is a harmful habit that may interfere with proper craniofacial development. The absence of nasal breathing with secondary development of mouth breathing is responsible for abnormal development of the oral-facial bone structures (Leung and Van Noy, 2024; Guilleminault et al., 2016). Mouth breathers demonstrated structurally an increased anterior facial height and overjet but decreased overbite and maxillary arch width. Mouth breathing children were likely to have an increased ratio of anterior lower facial height to posterior height with the clockwise rotation of the mandible (Habumugisha 2022; Harari et al., 2010; Farronato et al., 2020). Fortunately, these figures improved significantly following myofunctional treatment. As a reminder, I have shared in the past some other negative consequences of mouth breathing which include decreased nitric oxide production, increased oral bacteria and in tandem increased risks of gum disease and dental decay. That’s one explanation why mouth breathers will have morning breath, too. A recent systematic review showed that myofunctional treatment improved snoring and mouth breathing habits (Carrasco-llatas & Connor-reina, 2021).

Developmentally and behaviorally, pediatric mouth breathers have demonstrated abnormal maxillofacial morphology and poor academic performance (Habumugisha, 2022; Ribeiro et al., 2016; Morais-almeida et al., 2019). Lip and tongue muscle weakness is one of the clinical manifestations of mouth breathers, which leads to abnormal craniofacial development (Sabashi et al., 2011; Nishiura et al., 2015). It’s important to break the cycle: Kondo (2007) reported that OMT positively influenced the management of the different malocclusions and was crucial at the retention stage following orthodontic treatment. Saccomanno et al. (2012) similarly proposed that combining orthodontic therapy with OMT might optimize orthodontic treatment stability.

Leung and Van Noy (2024) similarly share that OMT can reduce the severity of SDB by maintaining airway patency during sleep. Measures of Apnea-Hypopnea Indices (AHI) decreased in both pediatric and adult populations with myofunctional therapy, also improving snoring, oxygen saturation, and reports of sleepiness (Camacho et al., 2015). OMT seems to help break the cycle of downstream mouth breathing effects, as well.

4.      OMT and non-nutritive sucking behavior elimination

Leung and Van Noy (2024) share that several studies demonstrate that non-nutritive sucking habits (NNSHs) may occur in up to 68% of children. Anterior open bites are associated with up to 38% of this population (Katz and Rosenblatt, 2005). Furthermore, prolonged NNSHs (36 months or more) may lead to dental malocclusion, altered tongue posture, and orofacial dysfunction. These changes, as mentioned earlier, can predispose children to SDB and impact overall craniofacial growth and development (Van Dyck et al., 2016). OMT targets appropriate tongue posture and nasal breathing to activate the parasympathetic response via the maxillary palate and vagus nerve, thus eliminating the need for NNSHs (American Academy of Pediatric Dentistry Policy on Pacifiers Reference Manual, 2023).

Green (2013) presents psychosocial benefits to OMT, in particular with eliminating non-nutritive sucking behaviors (NNSB). Green shared that poor self-esteem is associated with the negative effects of extended sucking behavior, which may also affect socialization skills. Furthermore, protrusive tongue activity often contributes to a triad of altered appearance, speech and open lips rest posture.

Following digit sucking remediation, Green noted that OMT practitioners may also need to address resting posture issues, and tongue thrust more aggressively together. Van Norman’s work in 1997 and Green’s study in 2010 had similar findings in this regard. Van Norman reported that 98 % of 723 subjects with digit sucking habits presented with tongue thrust swallow and/or low rest posture. Meanwhile, Green also reported that the vast majority of children (99% of 421 subjects) with digit sucking behavior demonstrate low rest posture of the tongue and or tongue thrust behavior. Sucking behavior places the tongue inferiorly in the oral cavity, often perpetuating this horizontally or inferior-based tongue posture cycle. Melink and colleagues  (2010) reported that low resting posture of the tongue due to sucking habits, or a short lingual frenum are associated with unilateral posterior crossbite in four- to five-year-olds.

Thus, in order to break this cycle, tongue, lip and jaw rest posture OMT techniques were initiated in Green’s case report (2013). This consisted of child and family education in the appropriate ‘resting spot’ location for the tongue, the concept of freeway space in relation to rest position, limited vertical tip and mid tongue elevation strategies, behavioral and environmental cues for conscious thought of rest posture, and retraining exercises to encourage vertical tongue propensity. Breaking these habits will help restore and optimize craniofacial growth patterns.

Green (2013): Habit Elimination, OMT and Open Bite Closure

6.      OMT and temporomandibular disorder (TMD) prevention

According to Maria de Felicio (2009), OMT has helped mitigate temporomandibular disorder (TMD). The authors observed significant reduction of pain sensitivity to palpation of all muscles studied, but not for the TMJs. There was an increase in the mandibular range of motion and reduced frequency and severity of signs and symptoms.

Furthermore, Habumugisha  et al. (2022) noted that functional orthodontic appliances significantly improved TMD symptoms in individuals with juvenile idiopathic arthritis and TMD (Isola et al., 2017). Oral habits have been considered a major etiology of TMD because they produce traumatic dental occlusion.

Evaluation of Myofunctional Issue Tree

Closing Summary

In conclusion, OMT is a highly collaborative function-based therapeutic approach to address orofacial muscle dysfunction. Incorporating OMT in tandem with orthodontic therapy has been shown to sustain a long-term outcome as well as an elimination of SDB, orofacial habit mitigation, and finally TMD prevention. I wanted to specify that myofunctional exercises do require cognitive stamina and compliance and in general is recommended as a consideration starting as young as age 4. Myofunctional disorders may be identified in infants, toddlers and younger children, as well, though. A pediatrist speech therapist and/or OT with oral-sensory motor and/or feeding therapy training, as well as a background in tethered oral tissues (i.e. tongue ties), may be a helpful resource in these cases. Hopefully more literature will be published to further hone and standardize OMT exercises and techniques.

Up next, I look forward to exploring and sharing the dynamics between occlusion with breathing, breathwork, and whole-body posture.

A special thank you to Ann Blau, OMT, who provided me with excellent references and resources. References available upon request