OFP EXTRA OSCE Q3 - Obstructive Sleep Apnoea

Worked answers for OFP EXTRA OSCE — Question 3.

Scenario

Sandra is a 58-year-old postmenopausal woman referred to your clinic by her general medical practitioner. She reports excessive daytime sleepiness, loud snoring, and unrefreshing sleep. Her husband has observed episodes of apnoea during the night. She has a BMI of 34 and a known history of hypertension managed with antihypertensives. On examination you note a high Mallampati score, retrognathic mandible, and clinical evidence of bruxism. Her referring practitioner suspects obstructive sleep apnoea (OSA) and has asked you to assess and manage her.

Questions

1. List 3 risk factors for OSA that are present in this patient. (3 marks)
2. Explain the pathophysiology of OSA and describe how it relates to oral manifestations. (3 marks)
3. Describe the role of the dentist in screening and diagnosing OSA. (3 marks)
4. Outline 2 oral appliances commonly used in OSA management and explain their mechanisms of action. (3 marks)
5. Describe 2 complications of untreated OSA relevant to dental and systemic health. (3 marks)
6. List 3 non-pharmacological lifestyle modifications that may reduce the severity of OSA. (3 marks)
7. What challenges may arise in the long-term management of OSA with oral appliance therapy? (3 marks)

(Total: 21 marks)

1. List 3 risk factors for OSA that are present in this patient.

Three risk factors clearly present in Sandra (do not list “male gender” — she is female):¹

• BMI of 34 (obesity, >32) — increased adiposity around the upper airway promotes pharyngeal narrowing and collapse.
• Hypertension — an established comorbidity and risk marker, bidirectionally linked with OSA.
• Retrognathic mandible — a craniofacial risk factor that posteriorly positions the tongue and narrows the upper airway.
• Other risk factors present in Sandra that could be cited: high Mallampati score (upper-airway crowding), and postmenopausal status with age >50, both of which raise OSA risk in women.

Mallampati score

A clinical classification (Class I–IV) of the oropharyngeal view obtained on maximal mouth opening with the tongue protruded, grading visibility of the soft palate, uvula, fauces, and tonsillar pillars. A high score (Class III–IV = only the soft/hard palate visible) indicates a crowded oropharynx and is associated with higher OSA risk.²

2. Explain the pathophysiology of OSA and describe how it relates to oral manifestations.

Pathophysiology:¹

• OSA results from repetitive collapse of the upper airway during sleep due to loss of pharyngeal muscle tone.
• Collapse leads to intermittent hypoxia and hypercapnia.
• Arousal responses cause sleep fragmentation and sympathetic nervous system activation.

Oral manifestations (how the pathophysiology relates):¹

• Increased respiratory effort and jaw bracing during airway obstruction may contribute to masticatory muscle hyperactivity and sleep bruxism.
• Chronic mouth breathing secondary to upper-airway obstruction can cause xerostomia and increased caries risk.
• Myalgia — potential for muscle pain related to bruxism and muscle hyperactivity.

3. Describe the role of the dentist in screening and diagnosing OSA.

The dentist’s role spans risk identification, screening, recognition of signs/symptoms, and onward referral:¹

• Identify risk factors through comprehensive history-taking and oral examination.
• Use validated screening tools — STOP-BANG questionnaire and Epworth Sleepiness Scale.
• Utilise the OSA-50 screening questionnaire.
• Recognise oral and craniofacial signs: retrognathia, macroglossia, scalloped tongue, high arched palate, enlarged tonsils, bruxism.
• Identify symptoms such as gasping during sleep.
• Evaluate for a long soft palate during clinical examination.
• Review medical history for comorbidities such as type 2 diabetes.
• Refer to a sleep physician for definitive diagnosis via polysomnography (in-laboratory) or home sleep testing.

4. Outline 2 oral appliances commonly used in OSA management and explain their mechanisms of action.

• Tongue retaining devices (TRDs) — hold the tongue in an anterior position via a negative-pressure bulb, preventing posterior displacement of the tongue and pharyngeal obstruction; can be used specifically for edentulous patients.¹
• Mandibular advancement appliances (MAAs / MADs) — protrude the mandible anteriorly to enlarge the upper airway, increase pharyngeal muscle tone, and reduce upper-airway collapsibility during sleep.¹
  • Mechanistically, MAAs increase pharyngeal space and reduce collapsibility through anterior movement of the mandible and tongue and lateral increase in velopharyngeal airway space, with the greatest effect seen in the velopharyngeal airspace.²

5. Describe 2 complications of untreated OSA relevant to dental and systemic health.

• Dental / orofacial complication — sleep bruxism (with related temporomandibular disorders), and xerostomia from chronic mouth breathing, increasing caries risk and exacerbating periodontal disease.¹
• Systemic complication — hypertension and increased risk of cardiovascular disease and stroke, plus type 2 diabetes, neurocognitive impairment, and excessive daytime sleepiness that impairs occupational and driving safety.¹

6. List 3 non-pharmacological lifestyle modifications that may reduce the severity of OSA.

• Weight reduction.¹
• Positional therapy — avoidance of supine (back) sleeping.
• Reduction or elimination of alcohol and sedatives before sleep.
• Additional measures: smoking cessation; regular physical exercise.

7. What challenges may arise in the long-term management of OSA with oral appliance therapy?

• Patient non-compliance with nightly appliance use.¹
• Orofacial discomfort — tooth soreness, masseter/jaw discomfort, or TMJ pain (and, early on, dry mouth or excessive salivation).¹²
• Appliance-induced occlusal changes over time — decreased overjet and overbite, anterior or posterior open bite development, and tendency toward a Class III relationship.¹²
• Need for ongoing titration, monitoring, and review of treatment efficacy — OSA may progress over time, requiring repeated adjustment and follow-up sleep studies.¹
• Appliance wear, fracture, or deterioration requiring repair or replacement.¹

Footnotes

1. OFP Mock Formative Q3 - Obstructive Sleep Apnoea_integrated — marking key. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³ ↩¹⁴

2. L35 Oral Appliance Therapy for Snoring and OSA. ↩ ↩² ↩³ ↩⁴