Myofunctionals & airways – separating myth from reality: Peter Miles. Episode 79. April 4th 2021

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Farooq Ahmed


Join me as I summarise Pater Miles lecture exploring myofunctional appliances and the literature of the appliance


The following was covered

1.     Myofunctional appliances

2.     Evidence of Occlusal changes

3.     Airway influencing growth

4.     Myofunctional therapy

5.     Orthodontists role in Sleep disorder breathing


Claims by some manufacturers of myofunctional appliances:

·      Incorrect breathing from 2 years of age

·      Incompetent lips & mouth breathing – aesthetic effects

·      Crooked teeth

·      Long face

·      Behavioural changes, tired / hyperactive



Claimed effects of myofunctional appliances treatment

·      Improve facial growth

·      Skeletal growth

·      Better alignment

·      Stable


Myofunctional Appliances how do they work?


Design – off the shelf design

·      Monoblock Kesling positioner type appliance 1945:

·      Double mouthguard postured into edge to edge position

·      Postured edge to edge

·      Example Occlus-o-guide, LM activator, Myobrace



·      Retrocline uppers, procline lowers

·      Disocclusion posterior teeth = overeruption of posterior teeth, overbite improvement




Occlusal changes with appliances



·      Eruption Guidance Appliance, T4K, LM activator AJODO 2008 Angle 2019

·      Overjet  2mm improvement

·      Overbite 2mm improvement

·      Crowding reduction 2mm

·      Relapse towards baseline Janson, significant for OB crowding and 25% for OJ 2007

·      Time 13-43 months

o   Small changes over a long period, options to treat later Obrien 2003


Myobrace Vs Activator  EJO 2015

·      Poor compliance: PFA 70% non-compliance, 53% Activator non-compliance (Twinblock 84% compliance AJODO 2003)

·      2018 cost benefit analysis: PFA minimised costs


Airway evidence


Difficult to show direct changes, so related parameters are used.


Claimed issues with narrow airway and mouth breathing:

1.     Dental: Crooked teeth and arches

2.     Lip incompetence

3.     Skeletal: long face

4.     Behaviour tired and hyperactive



1: Crooked teeth and narrow arches

o   Prevalence of malocclusion similar in Paediatric sleep disorder breathing in the population J den Sleep Medicine 2017


2: Lip incompetence


·      Vig 1979

o   Lip growth accelerate sand overtakes facial height 9-13

o   Lip incompetence will improve with age

·      Vig 1881

o   Lip incompetence no difference in nasal airflow

§  Cannot conclude lip incompetence = mouth breather

o   Proffit – long face still use nose to breath, but less than normal face type



3: Skeletal: long face


·      Craniofacial morphology metal analysis: AJODO 2013

o   Paediatric OSA statistically significant in class 2, 1.5-1.6o – NOT clinically significant or diagnostically useful

§  Direct casual relationship of craniofacial structure and paediatric sleep disorder is unsupported in meta analsysis



Myofunctional therapy




Oropharyngeal exercises

·      Aim to improve tone of surrounding muscles, phalangeal muscles, soft palate,  airway – increase patency

o   Reduce AHI index by half short term studies 3 months Am J resp Crit Car Med 2009, Sleep Med 2013


Orthodontists role in Sleep Disorder Breathing

·      We are not the primary care giver

·      Main role: Screening / Assessment, questionnaire

o   Paediatric sleep questionnaire

§  Effective ruling out OSA / SDB

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