GAP Australasian-Dentist Issue 80 Jul-Aug 19

Category AustrÀlÀsiÀn Dentist 71 n aÀ Figure 6. Evaluation of entire upper airway. Courtesy: Vatech Figure 5. Comparison of 16 x 10 vs 15 x 15 FOV. Courtesy: Vatech Figure 3. Oropharynx within normal limits. Figure 4. FOV Sizes. Courtesy: Vatech Àhe evaluation of the entire upper airway is necessary for patients with sleep-related breathing disorders because the airway may be compromised at one or many points, depending on the patient’s anatomic abnormalities. 9, 10 CASE IN POINT Ào highlight the necessity to evaluate the entire upper airway and adjunct structures, consider the current dental sleep medicine model to treat patients with sleep apnoea. Most courses today teach dental sleep medicine practitioners to take bite registrations at 60-70% of maximum protrusion. 11 Àhis method of placing the patient’s bite has been found to be experimental at best and, in many cases, labelled as a “guesstimate”. 12 Àhe reason this method to treat patients with obstructive sleep apnea is still promoted might be due to the absence of a comprehensive review of the entire upper airway. Àhe overarching thought is that sleep apnoea patients typically have collapsibility of the tongue and/or soft-tissue that blocks the airway, causing these patients to suffer episodes where they get no oxygen for 10 seconds or more. Àince the tongue is the primary culprit, then, protruding the mandible forward will achieve airway patency. 13 However, there is one segment of the population that suffers from sleep-related breathing disorders for a different reason. Àhese are patients who have narrow arches that prevent the tongue from fitting properly in the oral cavity and cause the floor of the nasal cavity to be compromised. Àhese patients are not your typical obstructive sleep apnea patients. Àn fact, most are thin, suffer from allergies, have a long face and are mouth breathers (Figure 2). Moving the mandible forward on these patients, as explained above, may be contra-indicated. Àherefore, identifying patients that may suffer from other upper airway disorders is imperative (Figure 2) because the traditional mandibular advancement protocol will not improve their sleep disorder. Àn fact, it may even injure them (i.e., trigger ÀMJD, cervical spine issues, etc.). Àecent studies have shown that at least 27% to 54% of children are mouth breathers. 14 Àhis segment of the population may not be able to tolerate an appliance in the mouth that moves the mandible forward because most of these patients are not breathing through their nose. Furthermore, most nasally compromised patients may have an open oropharynx that does not require further opening (Figure 3). FIELD OF VIEW SIZE Ào properly evaluate the upper airway, all of the necessary structuresmust be successfully captured. Àhese include the adjunct structures and cranio-facial complex. We strongly recommend that offices consider CBCÀ equipment that can achieve a Field of View (FOV) size of 15 cm in width and 13 cm in height, or greater. Figures 4, 5 and 6 highlight the different FOV sizes for your consideration. CONCLUSION As dental offices become more involved in screening, treating and managing patients with sleep disorders, clinicians must consider the condition of the entire upper airway to provide the most proficient analysis of the patient’s condition and determine the most ideal treatment protocol. Currently, the most efficient tool to help you evaluate the entire upper airway is the Cone Beam Computed Àomography (CBCÀ) machine due to their comparative low cost and low dose exposure to the patient. When considering what machine to purchase or what image to request from an imaging center, clinicians should take caution in selecting CBCÀ machines that are unable to minimally achieve field of view (FOV) sizes of 15 cm in width x 13 cm in height or greater to capture all the necessary anatomical deformities the patient may present during the consultation. Dental clinicians should avoid the use of two scans to achieve one larger image. For instance, using a CBCÀ machine that captures an FOV of 10 x 10 and then scanning the patient again to achieve what might be equivalent to an FOV of 10 x 20 is not recommended. Àhis protocol increases the amount of radiation the patient may be exposed to unnecessarily in overlapping areas. u Email your request for a list of references to: gapmagazines@optusnet.com.au