Research and Evidence

On this page will be scientific research and evidence to support the protocols we implement at Sydney Airway Clinic

Obstructive sleep apnoea


CPAP was never meant to be a long-term therapy. It’s an excellent life-saving acute treatment. However long term use has a significant effect on breathing. The ‘night-time manipulation’ of breathing affects daytime function. Conversely, when CPAP is removed, the brain has to halt for a moment and consider what to do next. What it does is to revert to the entrenched dysfunctional daytime breathing patterns that were initially the root of the problem.

The take-home messages from this article from 2020 are:

If nocturnal breathing is being machine manipulated ( from CPAP) there will be changes to the natural breathing reflex response. CPAP may potentially lead to the onset of central sleep apnoea in patients with obstructive sleep apnoea that had initially been successfully controlled by CPAP.

Tongue and myofunctional therapy

The most recognised way to measure a tongue tie: Dr Audrey Yoon’s tongue range of motion ratio.

Myofunctional therapy reduces the severity of sleep apnoea by 50% in adults and 62% in children

More than 90% of patients (of all ages) are satisfied with the improvement in health after lingual frenectomy (tongue tie release) and myofunctional therapy.

Blocked nasal passages result in significant dysfunction of the tongue, lip and cheek muscles. This impacts speech, swallowing, chewing, posture and ofcourse breathing. It is imperative that children and adults be re-educated in myofascial behaviours. If this is not done, the muscle dysfunctions continue and breathing-disordered sleep persists.




Homeoblock and Vivos

The Homeoblock and Vivos appliances deliver intermittent, cyclical, light mechanical forces intraorally to effect bone morphogenesis.

This research paper shows that these types of forces “induced a significant increase in the mRNA expression of the osteogenesisspecific markers type-I collagen (Col1A1), osteonectin (SPARC), bone morphogenetic protein 2 (BMP2), osteopontin (SPP1), and osteocalcin (BGLAP) in osteogenic differentiated MSPCs [mesenchymal stem and progenitor cells]”

Furthermore, in this article:

  • cyclic loading of one suture has been shown to increase sutural strain to neighbouring sutures as well
  • Chewing (mastication) compresses sutures. However, by straining the sutures through forces delivered by the Homeoblock and Vivos appliances, it is possible to widen the suture and create bone apposition

Ted Belfor’s article in 2010 in the New York State Dental Journal, exhibiting how the Homeoblock improves airway volume in patients.

This article provides evidence to show that there is a 30% increase in transverse dimension of the upper jaw. The final conclusion is that “dental and facial changes associated with the Homeoblock’ removable orthodontic appliance are consistent with a broader smile and a more symmetrical facial appearance in non-growing adults.”


The ideal position for the temporo-mandibular joint is the Gelb 4/7 position.

Orthodontic Expansion

Orthodontic expanders are necessary to develop the transverse width of the upper jaw. Research, even as recent as 2021, shows that reduced width of the upper jaw is a predictor of multiple site obstruction in patients. So orthodontic expansion is so important!

Mouth breathing

Growth retardation

Mouth breathing has been shown to reduce growth hormone release which retards growth (Morais-Almeda et al). The growth hormone levels are restored once the mouth breathing is treated. 

Postural effects

Mouth breathing adversely affects posture (Neiva et al, January 2018). Infact, removing tonsils has been shown to immediately improve the posture of mouthbreathing children (Neiva et al, April 2018).