Systematic assessment of the impact of oral appliance therapy on the temporomandibular joint during treatment of obstructive sleep apnea: long-term evaluation

Occurrence of Temporomandibular Disorders among patients undergoing treatment for Obstructive Sleep Apnoea Syndrome (OSAS) using Mandibular Advancement Device (MAD): A Systematic Review conducted according to PRISMA guidelines and the Cochrane handbook for systematic reviews of interventions

BACKGROUND

Patients undergoing mandibular advancement device (MAD) therapy for obstructive sleep apnea (OSA) may experience changes in jaw position and altered occlusion. This could potentially contribute to the development or exacerbation of TMD symptoms. The literature on the long-term impact of MAD treated for OSA on TMD is scarce. Hence, this review was undertaken to ascertain the occurrence of TMD in MAD users.

METHODS

A comprehensive search protocol was implemented across several online databases using MeSH keywords and Boolean operators. A standardised data extraction form was developed specifically for this review. Two reviewers independently extracted the data. RoB-2 was used to evaluate the methodological quality of the included studies.

RESULTS

A total of 13 clinical studies were selected for this review. Some studies reported a significant reduction in the severity and frequency of TMD symptoms following MAD treatment. However, other studies did not observe significant changes in TMD symptoms or TMJ-related parameters from baseline to follow-up intervals. Temporary increases in TMJ-related pain or symptoms at the beginning of the follow-up period, which later subsided, were reported in some studies. Overall, MAD was not discontinued in any OSA patient due to TMDs.

CONCLUSION

The findings reveal that different outcomes associated with TMD are affected differently by MAD treatment for OSAS. According to a few studies, MAD therapy significantly reduced the severity and frequency of TMD symptoms. Other research, however, found no appreciable modifications in TMD symptoms or TMJ-related indicators. Although the overall results point to no significant effect of MAD treatment on TMD symptoms, the disparity in results between studies highlights the need for additional studies using standardised approaches.

Comparative evaluation of the efficacy of customized maxillary oral appliance with mandibular advancement appliance as a treatment modality for moderate obstructive sleep apnea patients-protocol for a randomized controlled trial

Background

Obstructive sleep apnea (OSA) is due to the obstruction of the upper airway during sleep. This condition is often associated with multiple symptoms and co-morbidities. There are many treatment options mentioned in the literature to manage OSA, among which interventional option of continuous positive airflow (CPAP) and non-interventional option, i.e., mandibular advancement device (MAD), which is an oral appliance (OA), are the most preferred ones. This study aims to evaluate the efficacy of customized maxillary oral appliances with mandibular advancement devices in moderate OSA patients.

Methods

A prospective interventional study with a randomized controlled trial will be carried out involving 40 participants (sample size), with an apnea-hypopnea index (AHI) > 15–30, recorded on polysomnography (PSG). Study participants will be randomly divided into the following treatment groups: control group or group subjected to mandibular advancement device (MAD, n=20) and second group subjected to customized maxillary oral appliance (CMOA, n=20). Baseline assessment of apnea/hypopnea index (AHI), oxygen saturation in blood, percentage of rapid eye movement, electroencephalogram, electrocardiogram, oro-nasal airflow via a pressure transducer, and Epworth Sleepiness Scale will be done. Then both study group participants will receive their respective appliances. And after one month and three months of delivery of the appliance, all the parameters, i.e., AHI, oxygen saturation in blood, percentage of rapid eye movement, electroencephalogram, electrocardiogram, oro-nasal airflow via a pressure transducer, and Epworth Sleepiness Scale will be re-evaluated and compared with the baseline measurements. Descriptive and analytical statistics will be done. SPSS (Statistical Package for Social Sciences) Version 20.1 will be used as statistical software. The statistical significance between the two groups after one month and three months will be evaluated at p< 0.05.

Discussion

We expect, customized maxillary oral appliance to be more efficient in managing moderate OSA, in comparison with MAD. If the hypothesis of the present study is confirmed, then this customized maxillary appliance will be quoted as a “gold standard” for managing moderate OSA.

Trial registration

CTRI/2020/07/026936 Registered 31 July 2020.

Long-term dentoskeletal side effects of mandibular advancement therapy in patients with obstructive sleep apnea: data from the Pays de la Loire sleep cohort

OBJECTIVES

Mandibular advancement devices (MADs) are the main therapeutic alternative to continuous positive airway pressure for obstructive sleep apnea. Our aim was to evaluate the long-term dentoskeletal side effects of MADs and to identify the predictive factors for these side effects.

MATERIALS AND METHODS

Patients from the Pays de la Loire cohort treated with a custom-made MAD for at least 1 year were included in this retrospective study. Digital cephalometric analyses were performed at baseline and at follow-up.

RESULTS

We included a total of 117 patients, treated with a MAD for a median [interquartile range] of 4.6 [2.6-6.6] years. The main significant side effects were a decrease in overbite (- 0.5 ± 1 mm), overjet (- 0.7 ± 1 mm) and maxillary incisor inclination (- 2.5 ± 2.8°) and an increase in mandibular incisor inclination (+ 2.2 ± 2.7°). Subjective side effects were not linked to the observed dentoskeletal changes. Current smokers were at higher risk of overjet modifications. A pre-existing anterior open-bite was associated with a greater decrease in overbite. Treatment duration was associated with a more pronounced mandibular incisor proclination. Propulsion was negatively associated with maxillary incisor retroclination.

CONCLUSIONS

Long-term dentoskeletal side effects were mainly moderate dental side effects. Some predictive factors were shown to be associated with more pronounced changes. Subjective side effects did not appear to be reliable tools to detect dentoskeletal side effects.

CLINICAL RELEVANCE

Regular follow-up with clinical examination and regular radiographs is mandatory. The predictive factors could be of interest for a better selection of patients and to individualize follow-up.

Obstructive Sleep Apnea: Non-positive Airway Pressure Treatments

Undiagnosed and untreated obstructive sleep apnea (OSA) is associated with health comorbidities and negatively affects quality of life. Alternative treatments should be considered in patients who are unable to tolerate or benefit from positive airway pressure treatment. When properly indicated, positional devices, oral appliances, airway surgery, and hypoglossal nerve stimulation have been shown to be effective in treating OSA. Hypoglossal nerve stimulation is a successful second-line treatment with low associated morbidity and complication rate.

Effect of mandibular advancement device on the stomatognathic system in patients with mild-to-moderate obstructive sleep apnoea-hypopnoea syndrome

Objective

This study was conducted to evaluate the changes of temporomandibular joints (TMJs) through magnetic resonance imaging (MRI) scanning and the electrical changes in mandibular movement and masticatory muscle surface of mild‐to‐moderate obstructive sleep apnoea‐hypopnoea syndrome (OSAHS) patients before and after treatment with mandibular advancement device (MAD).

Methods

This was a single‐centre, prospective study recruiting OSAHS patients undergoing treatment with MAD in Department of Stomatology, Yannan Hospital, Kunming, China. Patients were recruited from February 2015 to October 2015, and TMJ changes were observed in MRI scanning before and after 18 months of treatment with MAD in cohort 1. The second cohort of the patients were recruited from January 2014 to September 2015 and electrical changes in mandibular movement and masticatory muscle surface of patients before and after 6 months of treatment with MAD.

Results

In the cohort 1, TMJ changes analysed through MRI scanning, before and after 18‐month treatment with MAD, there was no significant deviation in the angle of joint disc position. A minor change in the position relationship between condylar process, articular disc and articular fossa but not significant was observed. There was no significant difference in the shape and magnitude of mandibular incision edge movement, percussion movement, masticatory movement and condylar central trajectory among the recruited OSAHS patients, before and after 6 months of MAD treatment as analysed through electromyography.

Conclusion

In this study, from the results it was evident that the effect of MAD on the stomatognathic system of OSAHS patients is minimal.

Oral appliance therapy versus nasal continuous positive airway pressure in obstructive sleep apnea: A randomized, placebo-controlled trial on temporomandibular side-effects

Purpose

To assess the differences in the frequency of clinical signs of temporomandibular disorder (TMD) pain and mandibular function impairment between mandibular advancement device (MAD) and nasal continuous positive airway pressure (nCPAP) therapies in obstructive sleep apnea (OSA) patients at baseline and after 6 month of treatment.

Methods

This study concerns a secondary analysis of a randomized placebo‐controlled trial in which different treatment effects of an objectively titrated MAD were compared with those of nCPAP and an intra‐oral placebo appliance in a parallel design. Sixty‐four mild to severe OSA patients (52.0 ± 9.6 years) were randomly assigned to these three groups. All patients underwent a shortened functional examination of their masticatory system at baseline and after 6 months to establish the presence of clinical signs of TMD pain. Mandibular function impairment was assessed with a questionnaire.

Results

Clinical signs of TMD pain were only rarely present at baseline and therapy evaluation. No significant differences were found between the three groups in the (low) frequency of clinical signs of TMD pain at both time points (p = .401–.176). In addition, the (low) scores of mandibular function impairment did not differ between the three groups either, neither at baseline (p = .744) nor after 6 months (p = .359).

Conclusions

A low frequency of clinical signs of TMD pain in mild to severe OSA patients was found after 6 months, regardless of treatment with MAD or nCPAP. In addition, no difference in mandibular function impairment was observed between the different treatment modalities.

Dental side effects of long-term obstructive sleep apnea therapy: a 10-year follow-up study

OBJECTIVES

Patients with obstructive sleep apnea (OSA) are usually treated with either mandibular advancement device (MAD) or continuous positive airway pressure (CPAP) therapy. The objective of this study is to evaluate changes in dental occlusion associated with long-term MAD and CPAP therapy.

MATERIALS AND METHODS

Data from 14 OSA patients using MAD and 17 OSA patients using CPAP therapy were evaluated at baseline, 2-year and 10-year follow-up. Changes in dental occlusion were analyzed from dental plaster casts with a digital sliding caliper.

RESULTS

At 2-year follow-up, MAD therapy resulted in significant dental changes when compared with baseline values. In MAD therapy, overjet and overbite decreased with 1.1 ± 1.8 mm and 1.1 ± 1.2 mm respectively. With CPAP therapy overjet and overbite decreased significantly with 0.2 ± 0.5 mm and 0.3 ± 0.5 mm, respectively. Both groups also showed significant changes in molar occlusion. After a 10-year follow-up, significant and more pronounced changes were seen in overjet and overbite. In MAD therapy, overjet and overbite decreased with 3.5 ± 1.5 mm and 2.9 ± 1.5 mm respectively when compared with baseline values. In CPAP therapy, overjet and overbite decreased with 0.7 ± 1.5 mm and 0.8 ± 1.4 mm respectively when compared with baseline values.

CONCLUSIONS

This study demonstrates that MAD and CPAP therapy result in significant changes in dental occlusion. These changes appear progressive and more pronounced with MAD compared to CPAP therapy.

CLINICAL RELEVANCE

Long-term OSA treatment results in significant dental side effects that may progress over time. Informed consent is fundamental before starting MAD treatment and individualized long-term follow-up is of eminent importance.

Effect of long-term oral appliance therapy on obstruction pattern in patients with obstructive sleep apnea

PURPOSE

Oral appliance therapy is an alternative treatment modality for obstructive sleep apnea (OSA). However, there have been no studies to determine whether changes in the obstructive pattern occur following long-term use of oral devices. Therefore, we examined whether the obstructive pattern changes in patients with OSA who undergo long-term oral appliance therapy using drug-induced sleep endoscopy (DISE).

METHODS

We investigated 156 consecutive patients diagnosed with OSA. Seventy-nine of these patients were found to be eligible for inclusion in this study. All enrolled patients underwent two DISE examinations: before and after oral appliance use. We compared the DISE findings for each patient in terms of degree and configuration of airway obstruction at the levels of the velum, oropharynx, tongue base, and epiglottis.

RESULTS

We found that dental problems, as assessed using the average values of overjet and overbite, were significantly decreased after 2 years of oral appliance use. Comparisons of the DISE findings revealed that there was significant widening of the upper airway structures following long-term oral appliance therapy, especially in the velum (P = 0.022) and epiglottis (P = 0.001). However, changes in the configuration of upper airway obstruction were not observed in any of the structures of the upper airway.

CONCLUSIONS

We found evidence possibly indicating decreased obstruction at the levels of the velum and epiglottis after long-term use of oral appliances. We suggest further cohort studies to confirm these findings.

An update on mandibular advancement devices for the treatment of obstructive sleep apnoea hypopnoea syndrome

Continuous positive airway pressure (CPAP) remains the gold standard treatment for obstructive sleep apnoea hypopnoea syndrome (OSAHS). However, the high efficacy of CPAP is offset by intolerance and poor compliance, which can undermine effectiveness. This means that alternatives to CPAP are also necessary. In recent years, oral appliances have emerged as the leading alternative to CPAP. There is now a strong body of evidence supporting their use in OSAHS and clinical guidelines now recommend their use in mild OSAHS and in more severe cases when CPAP fails. These devices are by no means a homogenous group as they differ greatly in both design and action. The most commonly used appliances are mandibular advancement devices (MAD) that increase airway diameter with soft tissue displacement achieved by mandibular protrusion. Despite the growing evidence, there are still barriers to MAD provision. Their effectiveness can be difficult to predict and there is debate about the required level of design sophistication. These uncertainties prevent more widespread inclusion of MAD within clinical sleep services. This review will focus on the efficacy, effectiveness, design features, side-effects of and patient selection for MAD therapy. Comparison will also be made between MAD and CPAP therapy.

Long-term side effects on the temporomandibular joints and oro-facial function in patients with obstructive sleep apnoea treated with a mandibular advancement device

Patients with obstructive sleep apnoea (OSA) in long-term treatment with a mandibular advancement device (MAD) to increase the upper airway space may develop changes in the temporomandibular joint (TMJ) and the oro-facial function due to the protruded jaw position during sleep. The aim was to investigate the influence of long-term MAD treatment on the TMJs, oro-facial function and occlusion. This prospective study included 30 men and 13 women (median age 54) with OSA [Apnoea-Hypopnoea Index (AHI): 7-57]. They were examined with the Nordic Orofacial Test Screening (NOT-S), the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) and cone beam computed tomography (CBCT) of the TMJs. The examination was performed before MAD treatment (T0), and 3-6 months (T1, no CBCT), 1 year (T2) and 3 years (T3) after treatment start. The results were analysed as long term (T0-T3, n = 14) and short term (T0-T2, n = 24) by t-test, Fisher's exact test and anova. Both long- and short-term analyses revealed a reduction in AHI (P < 0·002). Significant long term were increased scores in the NOT-S Interview (P < 0·045), reduced vertical overbite (P < 0·031) and increased jaw protrusive movement (P < 0·027). TMJ changes were found as joint sounds in terms of reciprocal clicking and crepitus, short term as a decrease and subsequent recurrence (P < 0·053; P < 0·037). No significant radiological changes were found. In conclusion, MAD treatment is beneficial to some OSA patients, but might induce changes in the TMJs, the oro-facial function and the occlusion. However, these changes seemed to be less harmful than previously reported with careful adaptation, control and follow-ups.

Clinical effectiveness and cost-effectiveness results from the randomised controlled Trial of Oral Mandibular Advancement Devices for Obstructive sleep apnoea-hypopnoea (TOMADO) and long-term economic analysis of oral devices and continuous positive airway pressure

BACKGROUND

Obstructive sleep apnoea-hypopnoea (OSAH) causes excessive daytime sleepiness (EDS), impairs quality of life (QoL) and increases cardiovascular disease and road traffic accident risks. Continuous positive airway pressure (CPAP) treatment is clinically effective but undermined by intolerance, and its cost-effectiveness is borderline in milder cases. Mandibular advancement devices (MADs) are another option, but evidence is lacking regarding their clinical effectiveness and cost-effectiveness in milder disease.

OBJECTIVES

(1) Conduct a randomised controlled trial (RCT) examining the clinical effectiveness and cost-effectiveness of MADs against no treatment in mild to moderate OSAH. (2) Update systematic reviews and an existing health economic decision model with data from the Trial of Oral Mandibular Advancement Devices for Obstructive sleep apnoea-hypopnoea (TOMADO) and newly published results to better inform long-term clinical effectiveness and cost-effectiveness of MADs and CPAP in mild to moderate OSAH.

TOMADO

A crossover RCT comparing clinical effectiveness and cost-effectiveness of three MADs: self-moulded [SleepPro 1™ (SP1); Meditas Ltd, Winchester, UK]; semibespoke [SleepPro 2™ (SP2); Meditas Ltd, Winchester, UK]; and fully bespoke [bespoke MAD (bMAD); NHS Oral-Maxillofacial Laboratory, Addenbrooke's Hospital, Cambridge, UK] against no treatment, in 90 adults with mild to moderate OSAH. All devices improved primary outcome [apnoea-hypopnoea index (AHI)] compared with no treatment: relative risk 0.74 [95% confidence interval (CI) 0.62 to 0.89] for SP1; relative risk 0.67 (95% CI 0.59 to 0.76) for SP2; and relative risk 0.64 (95% CI 0.55 to 0.76) for bMAD (p < 0.001). Differences between MADs were not significant. Sleepiness [as measured by the Epworth Sleepiness Scale (ESS)] was scored 1.51 [95% CI 0.73 to 2.29 (SP1)] to 2.37 [95% CI 1.53 to 3.22 (bMAD)] lower than no treatment (p < 0.001), with SP2 and bMAD significantly better than SP1. All MADs improved disease-specific QoL. Compliance was lower for SP1, which was unpopular at trial exit. At 4 weeks, all devices were cost-effective at £20,000/quality-adjusted life-year (QALY), with SP2 the best value below £39,800/QALY.

META-ANALYSIS

A MEDLINE, EMBASE and Science Citation Index search updating two existing systematic reviews (one from November 2006 and the other from June 2008) to August 2013 identified 77 RCTs in adult OSAH patients comparing MAD with conservative management (CM), MADs with CPAP or CPAP with CM. MADs and CPAP significantly improved AHI [MAD -9.3/hour (p < 0.001); CPAP -25.4/hour (p < 0.001)]. Effect difference between CPAP and MADs was 7.0/hour (p < 0.001), favouring CPAP. No trials compared CPAP with MADs in mild OSAH. MAD and CPAP reduced the ESS score similarly [MAD 1.6 (p < 0.001); CPAP 1.6 (p < 0.001)].

LONG-TERM COST-EFFECTIVENESS

An existing model assessed lifetime cost-utility of MAD and CPAP in mild to moderate OSAH, using the revised meta-analysis to update input values. The TOMADO provided utility estimates, mapping ESS score to European Quality of Life-5 Dimensions three-level version for device cost-utility. Using SP2 as the standard device, MADs produced higher mean costs and mean QALYs than CM [incremental cost-effectiveness ratio (ICER) £6687/QALY]. From a willingness to pay (WTP) of £15,367/QALY, CPAP is cost-effective, although the likelihood of MADs (p = 0.48) and CPAP (p = 0.49) being cost-effective is very similar. Both were better than CM, but there was much uncertainty in the choice between CPAP and MAD (at a WTP £20,000/QALY, the probability of being the most cost-effective was 47% for MAD and 52% for CPAP). When SP2 lifespan increased to 18 months, the ICER for CPAP compared with MAD became £44,066. The ICER for SP1 compared with CM was £1552, and for bMAD compared with CM the ICER was £13,836. The ICER for CPAP compared with SP1 was £89,182, but CPAP produced lower mean costs and higher mean QALYs than bMAD. Differential compliance rates for CPAP reduces cost-effectiveness so MADs become less costly and more clinically effective with CPAP compliance 90% of SP2.

CONCLUSIONS

Mandibular advancement devices are clinically effective and cost-effective in mild to moderate OSAH. A semi-bespoke MAD is the appropriate first choice in most patients in the short term. Future work should explore whether or not adjustable MADs give additional clinical and cost benefits. Further data on longer-term cardiovascular risk and its risk factors would reduce uncertainty in the health economic model and improve precision of effectiveness estimates.

TRIAL REGISTRATION

This trial is registered as ISRCTN02309506.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 18, No. 67. See the NIHR Journals Library website for further project information.

Clinical guidelines for oral appliance therapy in the treatment of snoring and obstructive sleep apnoea

The purpose of this review is to provide guidelines for the use of oral appliances (OAs) for the treatment of snoring and obstructive sleep apnoea (OSA) in Australia. A review of the scientific literature up to June 2012 regarding the clinical use of OAs in the treatment of snoring and OSA was undertaken by a dental and medical sleep specialists team consisting of respiratory sleep physicians, an otolaryngologist, orthodontist, oral and maxillofacial surgeon and an oral medicine specialist. The recommendations are based on the most recent evidence from studies obtained from peer reviewed literature. Oral appliances can be an effective therapeutic option for the treatment of snoring and OSA across a broad range of disease severity. However, the response to therapy is variable. While a significant proportion of subjects have a near complete control of the apnoea and snoring when using an OA, a significant proportion do not respond, and others show a partial response. Measurements of baseline and treatment success should ideally be undertaken. A coordinated team approach between medical practitioner and dentist should be fostered to enhance treatment outcomes. Ongoing patient follow-up to monitor treatment efficacy, OA comfort and side effects are cardinal to long-term treatment success and OA compliance.

Oral appliance treatment for obstructive sleep apnea: an update

Oral appliances (OA) have emerged as an alternative to continuous positive airway pressure (CPAP) for obstructive sleep apnea (OSA) treatment. The most commonly used OA reduces upper airway collapse by advancing the mandible (OAm). There is a strong evidence base demonstrating OAm improve OSA in the majority of patients, including some with more severe disease. However OAm are not efficacious for all, with approximately one-third of patients experiencing no therapeutic benefit. OAm are generally well tolerated, although short-term adverse effects during acclimatization are common. Long-term dental changes do occur, but these are for the most part subclinical and do not preclude continued use. Patients often prefer OAm to gold-standard CPAP treatment. Head-to-head trials confirm CPAP is superior in reducing OSA parameters on polysomnography; however, this greater efficacy does not necessarily translate into better health outcomes in clinical practice. Comparable effectiveness of OAm and CPAP has been attributed to higher reported nightly use of OAm, suggesting that inferiority in reducing apneic events may be counteracted by greater treatment adherence. Recently, significant advances in commercially available OAm technologies have been made. Remotely controlled mandibular positioners have the potential to identify treatment responders and the level of therapeutic advancement required in single night titration polysomnography. Objective monitoring of OAm adherence using small embedded temperature sensing data loggers is now available and will enhance clinical practice and research. These technologies will further enhance efficacy and effectiveness of OAm treatment for OSA.

Mandibular advancement appliances remain effective in lowering respiratory disturbance index for 2.5-4.5 years

OBJECTIVE

The mandibular advancement appliance (MAA) is now recognized as a first-line therapy option for mild to moderate obstructive sleep apnea syndrome (OSAS). The aim of this follow-up study was to re-assess the long-term efficacy of MAAs provided to patients in a previous comparative study.

METHODS

Sixteen subjects had participated in a previous comparative study in which the efficacy and compliance of two MAAs (Klearway - K and Silencer - S) were compared in a randomized cross-over design. At the end of the previous comparative study, subjects selected the MAA they preferred. Nine chose the K and seven the S. Fifteen subjects were available for a follow-up interview and 14 (4 women and 10 men; mean ± SEM: 51.9 ± 1.7 y.o.) agreed to participate in an overnight sleep recording at a hospital sleep laboratory from January to February 2009. The mean time lag between the end of the previous comparative study and the follow-up was 40.9 ± 2.1 months (range of 2.5-4.5 years). Comparisons were made across the three polysomnographic evaluations (PSGE): baseline, the night with the appliance of their choice at the end of the previous comparative study, and the follow-up night. Subjects completed the Epworth sleepiness scale (ESS), the fatigue severity scale (FSS), and a quality of life questionnaire (FOSQ).

RESULTS

At the follow-up, the respiratory disturbance index (RDI) remained significantly lower than baseline (p<0.001). Questionnaire responses revealed that ESS, FSS, and FOSQ remained improved at follow-up (p<0.02). Body mass index (BMI) increased slightly from baseline to follow-up (p<0.05). Diastolic and systolic blood pressure and cardiac rhythm decreased significantly from baseline to follow-up.

CONCLUSIONS

The MAAs remained effective in improving RDI, sleepiness, blood pressure, cardiac rhythm, fatigue, sleep quality, and quality of life over a period of 2.5-4.5 years. The rise in BMI is a concern that merits further examination.

Long-term oral appliance therapy in obstructive sleep apnea syndrome: a controlled study on temporomandibular side effects

The objective of this study was to assess variations in the occurrence of temporomandibular disorders (TMDs) and the risk of developing pain and function impairment of the temporomandibular complex in obstructive sleep apnea syndrome (OSAS) patients treated with either an oral appliance (mandibular advancement device) or continuous positive airway pressure (CPAP) in a 2-year follow-up study. In addition, we assessed the relationship between the mean mandibular protrusion and the frequency of wearing the appliance during follow-up with the occurrence of pain and function impairment of the temporomandibular complex. Fifty-one patients were randomized to oral appliance therapy and 52 patients to CPAP therapy. TMDs (diagnosed according to the Axis I Research Diagnostic Criteria for TMD), pain intensity and disability and mandibular function impairment were recorded at baseline, after 2 months, 1 year and 2 years of therapy. Only in the initial period of treatment the occurrence of pain-related TMDs was considerably higher (24%) in the oral appliance group compared to CPAP (6%). Oral appliance therapy furthermore resulted in more temporomandibular pain compared to CPAP (odds ratio 2.33, 95% confidence interval (1.22-4.43)). However, there were no limitations in mandibular function in both groups during the (entire) follow-up period. Although generally not serious and of transient nature, oral appliance therapy results in more pain-related TMDs in the initial period of use compared with CPAP therapy. Oral appliance therapy is associated with increased pain in the temporomandibular complex in the initial period of use. Because of the transient nature, this pain is not a reason to contra-indicate an oral appliance in OSAS patients. Moreover, TMDs and the risk of developing pain and function impairment of the temporomandibular complex appear limited with long-term oral appliance use.