Effects of Two Different Amounts of Mandibular Protrusion in OSA Patients Using Mandibular Advancement Appliance

Obstructive sleep apnea (OSA) is a complex disease associated with repeated closure of the upper airway during sleep which causes excessive daytime sleepiness. Daytime sleepiness can affects daytime performance undesirably and reduces driving performance causing an increased risk for accidents. It can also lead to high blood pressure, strokes, and eventually death.

Until now, there is no standardize value for the jaw advancement for the mandibular advancement appliance. It was found that when comparing the jaw advancement amount of 50% and above 50%, there is no additional efficacy. Efficacy of jaw advancement below 50% is lacking. Patients usually experience more complications with more advancement, there the investigators need to study the optimal mandibular advancement with least complication to the patients.

This is a single-center, double blind (patients and sleep analyst) prospective randomized controlled trial to be conducted at Faculty of Dentistry, University of Malaya.

Eligible and consented patients will be randomized into three groups using block randomization with allocation concealment. Patients in Group 1 and 2 will receive MAA set at 25%, 50% of maximum mandibular advancement respectively.

A general medical history will be recorded. Demographic data will be obtained from patients. Baseline measurements will be recorded as T0.

Alginate impressions of the upper and lower dental arches will be taken. Respective mandibular advancement record i.e. at 25% and 50% as assigned by block randomization will be registered using George Gauge. Monobloc type of MAA will then be custom-made for each patient.

Upon issue of MAA, patients will be given detailed instructions for the insertion, removal, storage, and maintenance of MAA. Patients will be advised to wear the MAA every night during sleep. Each patient will be reviewed one week after issue to assess for any problems encountered, adjust the MAA for comfort, and reinforce wear for compliance. Subsequent follow up will be scheduled at every 4-6 weeks. 6 months later, outcome measurements will be recorded as T1.

Baseline and outcome measurements at T0 and T1:

Baseline measurements will be performed prior to intervention (T0) and outcome measurements will be performed 6 months after issue of MAA (T1). Apnea-hypopnea index, minimum oxygen saturation, blood pressure, Epworth Sleepiness Scale(ESS), Calgary Sleep Apnea Quality of Life Index(SAQLI) and dental changes will be measured for both baseline and outcome records. Compliance to MAA and secondary effects caused by MAA will be assessed at T1.

Apnea-Hypopnea Index (AHI), minimum oxygen saturation (Min SaO2) and blood pressure:

AHI and MinSaO2 will be obtained from an overnight polysomnography (PSG) in the sleep laboratory, University of Malaya Medical Center (UMMC). Patient will be instructed to wear the MAA during PSG at T1.

Epworth Sleepiness Scale (ESS):

Daytime sleepiness is to be assessed using ESS. The Malay, Tamil, Mandarin, or English version of the ESS, wherever applicable will be completed by patients.

Calgary Sleep Apnea Quality of Life (SAQLI):

Patient will be interviewed for quality of life assessment using Malay or English version of SAQLI, wherever appropriate.

Compliance to MAA:

Compliance to MAA will be assessed using self-administered diary. Upon issue of MAA, each patient will be given a customized diary to record the frequency of MAA wear daily. The diary will be collected at every review at 4-6 weeks for analysis by calculating the percentage of night per week of wearing the MAA.

Secondary Changes after wearing MAA:

Secondary effect will be evaluated in a structured interview at every review at 4-6 weeks. Temporomandibular joint will be assessed using Diagnostic Criteria for Temporomandibular Disorders (DC/TMD).

Dental Changes after wearing MAA:

Dental changes will be measured with digital caliper and analysed using manual model analysis. The impressions for study models will be taken at T0 and T1.

Blinding:

A single clinician will treat all the patients and one dental technician will make all the MAA. The patient will be blinded to the amount of mandibular advancement. Sleep technician who carries out PSG will also be blinded. Clinician, however, is unable to be blinded due to the need to prescribe the MAA according to the randomization. All the data collected will be coded prior to blinded data analysis.

Proposed Data analysis:

All analyses are to be conducted using SPSS version 25.0. Shapiro-Wilk normality test will be used to evaluate for skewness. Parametric test will be used if the result is assumed normal but if not, non-parametric test will be used instead. Proposed parametric test are paired-sample t tests to test the null hypothesis of no differences AHI, MinSaO2, blood pressure, ESS, SAQLI, compliance and secondary effects, dental changes and demographic baselines between two groups. For the effect of different protrusion amounts and the difference in baseline body mass index(BMI) for both groups, independent T-test will be used instead.

Eligibility Criteria:
Inclusion Criteria:

1. Mild and moderate OSA patients who are keen on MAA
2. Severe OSA who had refuse CPAP
3. Aged 18 years and older
4. Without any form of prior treatment
5. Absence of any structural obstruction examined by otolaryngologist
6. Sufficient set of teeth to hold the appliance

Exclusion Criteria:

1. Presence of periodontal disease
2. Exaggerated gag reflex and temporomandibular joint disorder
3. Significant co-morbidity that could endanger the patient's health
4. Any psychiatric or neurological diseases previously known that could impair the compliance
5. Any medication intake that can influence sleep
6. Co-existing sleep disorders other than OSA for instance insomnia, central sleep apnea and etc
7. Pregnant candidates