Predictors of Side Effects With Long-Term Oral Appliance Therapy for Obstructive Sleep Apnea

Abstract

Study objectives: The aim of this study was to investigate the predictors of dental changes associated with long-term treatment with oral appliances (OAs) in patients with obstructive sleep apnea (OSA).

Methods: This was a retrospective study to investigate Japanese patients with OSA receiving long-term treatment with OAs. Comparisons of cephalometric analysis were carried out between the initial and follow-up assessments of dental and skeletal changes. Based on dental changes, predictors that may cause side effects were investigated.

Results: A total of 64 patients (average age at start of treatment: 57.7 ± 14.2 years, 44 males) were included in this study. The average duration of treatment was 4.3 ± 2.1 years. Over the total treatment period, there was a significant reduction in overjet (OJ) (1.5 ± 1.3 mm) and overbite (0.90 ± 1.5 mm), and an increase in the lower incisor line to the mandibular plane (3.1 ± 5.4°). A larger reduction in OJ of ≥ 1 mm was associated with treatment duration, use frequency, and mandibular advancement of the OAs. In addition to these predictive factors, the number of teeth was correlated with the amount of OJ reduction.

Conclusions: For long-term treatment with OAs, the risk of dental side effects should be considered, such as a reduction in OJ. A small number of maxillary teeth, as well as the factors associated with OAs, including treatment duration, use frequency, and mandibular advancement of the OAs, was correlated with an increased rate of OJ reduction.

Commentary: A commentary on this article appears in this issue on page 7.

Keywords: cephalometric analysis; dental side effects; long-term treatment; mandibular advancement devices; oral appliance; sleep apnea; snoring.

Figure 1. Cephalometric landmarks.

The following points were identified on lateral cephalograms. Points: S (sella) = the midpoint of the pituitary fossa), N (nasion) = the most anterior point on the frontonasal suture, ANS (anterior nasal spine) = the tip of the median, sharp bony process of the maxilla at the lower margin of the anterior nasal opening, A (Point A) = the deepest midline concavity on the anterior maxilla, B (Point B) = the deepest midline concavity on the mandibular symphysis, Pg (pogonion) = the most anterior point on the contour of the bony chin determined by a tangent through the nasion, Me (menton) = the intersection of the bony inferior symphysis with the inferior margin of the mandibular body, Go (gonion) = the constructed point of the intersection of the ramus plane and the tangent to the body of the mandible, Ar (articulare) = the point of intersection of the inferior cranial base surface and the averaged posterior surfaces of the mandibular condyles. Planes: SN (sella-nasion line) = the line through the sella and nasion, MP (mandibular plane according to Steiner) = the line through the gonion and gnathion, U1 (upper incisor line) = the line through the upper incisor apex and the upper incisor incisal edge, L1 (lower incisor line) = the line through the lower incisor apex and the lower incisor incisal edge. Linear measurements: OJ (overjet) = horizontal projection of maxillary teeth beyond the mandibular anterior teeth, usually measured parallel to the occlusal plane, OB (overbite) = vertical overlap of maxillary teeth over mandibular anterior teeth, usually measured perpendicular to the occlusal plane.

Figure 2. Correlation graphs of predictive factors and OJ reduction in bite changes.

The graphs show the correlation of reduction of OJ (mm) and each predictable factor. OJ = overjet.