Introduction: Obstructive sleep apnea (OSA) is a common sleep-related breathing disorder that affects more than 12 % of the US population. It is considered to be a serious problem associated with multiple physiological processes that affect normal body function including stroke, cardiovascular disease, hypertension, and type 2 diabetes. Risk factors for OSA include BMI higher than 35 kg/m2, male gender, neck circumference, and high blood pressure. The STOP-BANG questionnaire is a reliable screening tool for OSA; nevertheless, the gold standard for diagnosis of OSA is the overnight polysomnography (PSG) test. If the physician diagnoses a patient with OSA, different treatment modalities can be provided based on individual patient needs and preferences. OSA treatment modalities include positive airway pressure (PAP) therapy, surgery, and mandibular advancement devices (MADs). Even though PAP therapy is the gold standard treatment method for obstructive sleep apnea in adults, a large number of patients cannot tolerate it; therefore, for many of those patients, MADs are a valuable treatment alternative. MADs reduce the upper airway collapse by advancing the mandible and associated soft tissue; as a result, there is generally an increase in the upper airway volume at the oropharynges level and improvement in pharyngeal patency. Occasionally, treatment of sleep apnea with MADs may be associated with the development of symptoms of Temporomandibular Disorder (TMD) and posterior open bite (POB). The definition of TMD includes clusters of signs and symptoms affecting the masticatory musculature, temporomandibular joints (TMJ), and associated structures. Pain is one of the most common symptoms of TMD. TMD disorders have a high prevalence in the general population, which increases the probability that OSA patients who are referred for MAD therapy could already present with TMD, or possibly could develop it during MAD therapy. Another side effect of MAD is POB, defined as no occlusal contact between the maxillary and mandibular posterior teeth when the patients try to hold their jaws in a maximum intercuspation position. This study aims to evaluate the incidence and prevalence of TMD in OSA patients prior to receiving MAD, and to determine the overall prevalence of TMD problems and POB during MAD therapy. This study also aims to evaluate the effectiveness of daily physical medicine exercise instructions on management of TMD and POB development during usage of MAD.
Materials and Methods: This was a retrospective study for which medical records of UCLA patients were reviewed. In order to determine prevalence of TMD in OSA patients prior to receiving MAD, the charts of 195 patients who were referred to the UCLA Orofacial Pain Clinic between June 2016 to June 2019 for MAD therapy were screened as the study group. One hundred and fifty-five patients met the study group criteria. Additionally, we screened the data of 400 new patients in the UCLA School of Dentistry’s general dental clinic from June 2016 to June 2019 as control group. A total of 188 patients were included in the control group.
One hundred and four subjects of the study group met the criteria to investigate the prevalence of TMD problems and POB during MAD therapy. One hundred and one of the 104 patients whose data contained records of physical exercise compliance were included to explore the effectiveness of physical exercise protocols to manage and prevent TMD and POB during MAD therapy. The follow-up PSG data with oral appliance in place were available for 16 patients. These were reviewed to evaluate the efficacy of MAD in reduction of AHI (Apnea–Hypopnea Index). Successful management of OSA with MAD therapy was considered as at least 50% reduction of AHI compared to the respective baseline AHI.
Results: At baseline, TMD prevalence was 94% among the OSA patients and 28% in the control group, which was significantly different (p<0.05). Sixty-six percent of OSA patients who received MAD did not experience painful TMD, 24% had myalgia and only 8% had both myalgia and arthralgia during MAD therapy. The number of patients with painful TMD was significantly reduced from 98 patients at baseline to 34 patients after receiving MAD (p<0.05). Physical exercise protocols effectively and significantly reduced painful TMD during MAD therapy (p < 0.05). Incidence of POB was 11.5%, but daily jaw repositioning physical exercises reduced the prevalence and incidence of POB during MAD therapy. MAD therapy had successful outcome in 75% of the patients.
Conclusion: The prevalence of TMD in OSA patients is significantly higher compared to the control group. Therefore, it is crucial for dentists who provide MAD for OSA patients to have appropriate training and background to assess, diagnose, and document preexisting TMD, and to be able to manage signs and symptoms of TMD before MAD therapy. Physical exercise protocols are effective and valuable tools to manage and prevent possible side effects of MAD usage including TMD and POB. Therefore, physical exercise instructions should be given at the MAD-delivery visit and be emphasized during follow-up visits.