1. Neck Circumference > 16 in. women, > 17 in. men
It has been demonstrated, through several studies, that enlarged necks are associated with increased soft tissue volume in the throat area. Neck size can be associated with being overweight, same as waist size.
2. Mallampati > 2
The Mallampati Score  comprises a visual assessment of the distance from the tongue base to the roof of the mouth, and therefore the amount of space for an adequate airway. The score is assessed by asking the patient, in a sitting posture, to open the mouth and protrude the tongue as much as possible, rating in 4 classes:
- Class 1: Soft palate, uvula, fauces, pillars visible
- Class 2: Soft palate, uvula, fauces visible
- Class 3: Soft palate, base of uvula visible
- Class 4: Only hard palate visible
A higher Mallampati score is a predictor for risk of OSA and can be a helpful screening tool during the clinical examination. However, its role in predicting severity of OSA remains doubtful and needs further study. It should be noted that some individuals with a Mallampati 1 or 2 may have serious airway compromise.
3. Scalloped Tongue
The presence of tongue scalloping has shown a high correlation for abnormal AHI and nocturnal desaturation. The presence and severity of tongue scalloping has shown a positive correlation with increasing Mallampati. In high-risk patients, tongue scalloping has been found to be predictive of sleep pathology. Tongue scalloping is a useful clinical indicator.
4. 40% Tongue Restriction (Tongue-tie)
There are a few classifications of tongue movement. One classification of normal range of free tongue movement is greater than 16 mm. According to Kotlow’s assessment as follows:
- Class I: Mild ankyloglossia: 12 to 16 mm
- Class II: Moderate ankyloglossia: 8 to 11 mm
- Class III: Severe ankyloglossia: 3 to 7 mm
- Class IV: Complete ankyloglossia: Less than 3 mm.
Class III and IV tongue-tie category should be given special consideration because they severely restrict the tongue’s movement. Restrictions include limitations of movement protrusively, laterally, and vertically.
This screening measurement is effective for speech, but if we want to get a complete history of the tongue restriction, we want to look at the Tongue Range of Motion Ratio (TRMR). One screening evaluation involves:
- Have the patient open their mouth as wide as possible. Normal maximum opening is 40-50 mm.
- While maximally open, raise the tip of the tongue, attempting to touch the incisive papilla behind the upper central incisors. Successful touching represents “normal” tongue mobility. Tongue restrictions can be visualized as a percentage of movement from rest to full extension towards the incisive papillae. 40% restriction or greater often has significant clinical implications. Many patients appear to have mobility but they are using the jaw and floor of the mouth muscles and compensating to aid in mobility. For example, they could be a grade 3 mobility compensating to a grade 2 mobility by using the floor of their mouth muscles.
5. Nasal Stenosis
A simple observation can be made by having the patient breathe in and out through the nose. Does the nostril on one or both sides collapse during nasal breathing? This provides a visible indicator of nasal airway collapse or obstruction. It would be common that these patients struggle with upper airway resistance and default to mouth breathing.
6. Skeletal Profile
Maxillary and/or mandibular skeletal underdevelopment can compromise airway volume. Arnett’s True Vertical is a useful assessment for mandibular retrusion, maxillary retrusion, and bimaxillary (maxillo-mandibular) retrusion, by observing the patient’s profile, facing to the right. A line dropped vertically down from the nose-lip intersection (SN) relates ideally to the fully developed lower face when:
- Upper Lip = 2-5 mm in front of the line
- Lower Lip = 0-3 mm in front of the line
- Chin Point = -4-0 mm behind the line
Measurements less than these ranges can implicate craniofacial, mid-face underdevelopment, with increased risk for airway compromise.
1. ADA Adopts Policy on Dentistry’s Role in Treating Obstructive Sleep Apnea, Similar Disorders. ada.org October 23, 2017 News Releases
2. The Oxygen Advantage. Patrick McKeown 2015, William Morrow/Harper Collins Publisher
3. Implications of mouth breathing on the pulmonary function and respiratory muscles. Vern, H Antunes, A Milanesi J et.al Rev. CEFAC vol.18 no.1
São Paulo Jan./Feb. 2016
4. A frequent phenotype for pediatric sleep apnea: short lingual frenulum. Guilleminault C, Huseni S, Lo L ERJ Open Research 2016 2: 00043-2016
5. Which Oropharyngeal Factors Are Significant Risk Factors for Obstructive Sleep Apnea? An Age-Matched Study and Dentist Perspectives Nat Sci
Sleep. 2016; 8: 215–219
6. Mallampati Score, Wikipedia
7. Importance of Mallampati score as an independent predictor of obstructive sleep apnea. Kanwar M, Jha R European Respiratory Journal 2012 40:
8. The association of tongue scalloping with obstructive sleep apnea and related sleep pathology. Weiss TM, Atanasov S, Calhoun KH Otolaryngol
Head Neck Surg. 2005 Dec;133(6):966-71.
9. Ankyloglossia and its management. Chaubal T, Dixit M J Indian Soc Periodontol. 2011 Jul-Sep; 15(3): 270–272.
10. Ankyloglossia (tongue-tie): A diagnostic and treatment quandary. Kotlow LA. Quintessence Intl. 1999;30:259–62.
11. Impact of Mandibular Distraction Osteogenesis on the Oropharyngeal Airway in Adult Patients with Obstructive Sleep Apnea Secondary to
Retroglossal Airway Obstruction. Ramanathan Manikandhan, Ganugapanta Lakshminarayana, Pendem Sneha, Parameshwaran Ananthnarayanan,
Jayakumar Naveen, and Hermann F. Sailer. J Maxillofac Oral Surg. 2014 Jun; 13(2): 92–98.
12. Soft tissue cephalometric analysis: Diagnosis and treatment planning of dentofacial deformity. William Arnett, DDS, FACD, Jeffrey S. Jelic, DMD,
MD, Jone Kim, DDS, MS, David R. Cummings, DDS, Anne Beress, DMD, MS, C. MacDonald Worley, Jr, DMD, MD, BS, Bill Chung, DDS, Robert
Bergman, DDS, MSh. American Journal of Orthodontics and Dentofacial Orthopedics Volume 116, Number 3 September 1999 C. Colombo, MD,
Robert C. Basner, MD, Phillip Factor, DO, and Thierry H. LeJemtel, MD. Circulation. 2008 Apr 29; 117(17): 2270–2278.