Long-term side effects of sleep apnea treatment with oral appliances: nature, magnitude and predictors of long-term changes

Objectives: Oral appliances for the treatment of obstructive sleep apnea (OSA) reduce upper airway collapse by advancing the mandible (OAm) and associated soft tissues. OAm are well tolerated but have side effects, mainly dental movement. It is not yet clear whether there are irreversible skeletal changes associated with treatment. As oral appliance treatment for OSA is a life-long therapy, careful and extended follow-up of patients is required. The objectives of this study were to evaluate the magnitude and progression of the dental and skeletal changes associated with long-term treatment, in addition to determining the predictors of the changes.

Methods: Lateral cephalograms of adults treated for primary snoring or mild to severe OSA with a custom-made titratable OAm for a minimum of eight years were retrospectively studied. The magnitude and rate of progression of any changes over time was determined and initial patient and dental characteristics were investigated as possible predictors of the observed side effects.

Results: Records of 62 patients with an average treatment time of 12.6 years (range:8-21 years) were included. Cephalometric analysis revealed significant (p < 0.001) maxillary incisor retroclination (mean of ≈6°) and mandibular incisor proclination (mean of ≈8°) over the observation period. Maxillary incisors demonstrated a constant rate of retroclination -0.5°/year, the rate of mandibular incisors proclination was variable. The number of treatment years was significantly associated with these variables (p < 0.001). A greater body mass index (BMI) and Subspinale, Nasion, Supramentale angle (ANB) were associated with more maxillary and mandibular incisor proclination respectively. Although statistically significant (p < 0.001) skeletal changes were noted over this extended observation period, the difference in the Sella, Nasion, Supramentale point B (SNB) and mandibular plane angles were approximately 1° and were deemed not clinically significant.

Conclusions: This study represents the longest observation period to date examining OAm side effects with up to 21 years of follow up for some patients. It confirms that there are significant and progressive dental changes with prolonged OAm use. Conversely, over the same time period skeletal or postural changes were negligible. Additionally, treatment duration was the predictor consistently associated with the magnitude of the observed side effects.