3D analysis of upper airway morphology related to obstructive sleep apnea severity.

BACKGROUND: Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder characterized by repetitive collapse of the upper airway during sleep. However, little evidence is available on the differences between the sub-regions of the upper airway morphology and OSA severity. Since orthodontists frequently perform cone beam computed tomography (CBCT) in the neck area, we aimed to investigate the relationship and the differences between upper airway morphology and OSA severity using CBCT. MATERIALS AND METHODS: The medical records, CBCT imaging of 21 OSA patients diagnosed by polysomnography, and the apnea-hypopnea index (AHI) results were included to classify OSA severity as mild, moderate, or severe. The minimum cross-sectional areas (MCA) and volumes of the upper pharyngeal airway boundaries in four sub-regions: nasopharynx, retropalatal, retroglossal, and hypopharynx were measured. Dolphin Imaging software was used for upper airway segmentation. The correlation coefficient (r), one-way ANOVA, and the least significant difference post hoc multiple comparison test were applied to fulfill the objectives. RESULTS: A statistically significant relationship was found between the MCA of the nasopharynx and the AHI (r = -0.473, P < 0.05). Furthermore, a difference was found between mild and moderate and moderate and severe OSA severity in the MCA results of the retroglossal region (P < 0.05). However, no relationship was found between the upper airway volume and OSA severity. CONCLUSIONS: MCA was moderately negatively correlated to AHI only in the nasopharynx subregion. Moderate OSA presented significantly less MCA than mild and severe OSA only in the oropharynx and retroglossal subregions.

Prevalence and predictors of sleep bruxism in patients with obstructive sleep apnea and the effect of positive airway pressure treatment.

BACKGROUND: Sleep bruxism (SB) is often found to co-exist with obstructive sleep apnea (OSA). However, there are no data on prevalence and risk factors of SB in patients with OSA patients regarding the effect of optimal positive airway pressure (PAP). OBJECTIVE: This study aimed to study prevalence and risk factors of SB in OSA and to compare SB episodes during pre-treatment versus during optimal PAP therapy. METHODS: This investigation was a retrospective study including randomly selected patients with OSA who underwent split-night polysomnography. Data were collected from August 2021 to October 2022. Clinical demographic data and SB data were analyzed. The association between SB episodes and obstructive respiratory events were manually reviewed. If most of the SB episodes were observed within 5 s following obstructive respiratory events, SB was defined as SB associated with OSA. Comparison of SB index (SBI) was made between baseline portion of the study versus during optimal PAP. RESULTS: Among 100 patients enrolled, mean age was 50.8 ± 16.7 years and 73 subject (73%) were male. Mean respiratory disturbance index (RDI) and mean nadir oxygen saturation were 52.4 ± 33.4 and 79.3 ± 11.2% respectively. During the baseline portion of the study, 49 patients (49%) had SB and 31 patients (31%) had severe SB (SBI ≥ 4). Sleep bruxism associated with OSA was observed in 73.5% of all SB. The risk factor for SB was endorsement of nocturnal tooth grinding (odds ratio (OR) 5.69, 95%CI 1.74-18.58). Risk factors for severe bruxism were male sex (OR 4.01, 95%CI 1.02-15.88) and endorsement of nocturnal tooth grinding (OR 9.63, 95%CI 2.54-36.42). Risk factors for SB associated with OSA were non-supine RDI (OR 1.02, 95%CI 1.001-1.034) and endorsement of nocturnal tooth grinding (OR 5.4, 95%CI 1.22-23.93). In SB group, when comparison was made between baseline portion and during optimal PAP, significant reduction of SBI was observed (5.5 (3.2, 9.3) vs. 0 (0, 2.1), p < 0.001). Median difference of SBI between baseline portion and during optimal PAP was 4.4 (2.0, 8.3) (p < 0.001). CONCLUSIONS: In this group of patients with OSA, almost half was observed to have SB in which the majority were associated with OSA. Optimal PAP resulted in a significant reduction in SB episodes. In addition to endorsement of nocturnal tooth grinding, non-supine RDI was observed to be a potential risk factor for SB associated with OSA.

Efficacy of oropharyngeal exercises as an adjuvant therapy for obstructive sleep apnea: A randomized controlled trial.

PURPOSE: Some patients with mild-to-moderate obstructive sleep apnea (OSA) undergoing mandibular advancement device (MAD) therapy may exhibit residual sleep-breathing abnormalities. These cases require adjunctive treatment to further reduce the remaining airway inadequacy, which may affect the health and quality of life. This clinical trial was conducted since the oropharyngeal exercise, which aims to enhance the muscular function of the upper airway, combined with MAD, is unknown. We assessed the possible improvements in respiratory event parameters and lip and tongue physiological properties in patients with OSA who received oropharyngeal exercises for 2 months as an adjunct to MAD therapy. METHODS: Twenty-three participants with OSA who had been using MAD but still had residual apnea-hypopnea were randomly allocated to either the oropharyngeal exercise (OE group; N=12) or the sham exercise group (N=11). Lip and tongue strength, endurance, daytime sleepiness, respiratory event index (REI), and the lowest oxygen saturation (SpO2 nadir) were determined. RESULTS: Within and between the treatment groups, no significant improvement in the REI or SpO2 nadir was found. In both groups, there was a significant reduction in the Epworth Sleepiness Scale at 2 months (OE, P = 0.02; control, P = 0.02). In the OE group, lip endurance (P = 0.03), anterior tongue strength (P = 0.02), and endurance (P = 0.02) increased after 2-month of exercise, but only anterior tongue endurance increased significantly compared with the sham control (P = 0.01). CONCLUSIONS: This study found that adjunctive OE to MAD showed no additive effect in treating patients with moderate OSA who had a mild residual apnea-hypopnea index following MAD treatment. However, the exercises successfully enhanced lip and anterior tongue endurance, as well as anterior tongue strength.

Dental Sleep Medicine Education Amongst Accredited Orthodontic Programmes in Thailand.

BACKGROUND: Dental sleep medicine education (DSME) should be emphasised in postgraduate orthodontic training; however, there appears to be no clear guideline for its implementation into the curriculum. OBJECTIVE: The aim was to investigate the current status of DSME as well as its feasibility and implementation in postgraduate orthodontic programmes. METHODS: A structured interview with predetermined response options was chosen as a data collection method to gather relevant information from representatives of all accredited postgraduate orthodontic programmes in Thailand. These interviews were conducted online via the Cisco Webex Meeting platform. A combination of data analysis techniques was employed to achieve a thorough comprehension of the research findings, including descriptive statistics, quantitative content analysis, thematic analysis, and alignment analysis. RESULTS: All participating programmes reported the inclusion of DSME in their curricula. A didactic approach was adopted by all programmes. However, only 2 out of 7 programmes offered clinical sessions for their students. Several challenges in implementing DSME within orthodontic programmes were identified, including a shortage of expertise and limited patient access. The participants also suggested that knowledge and resource sharing amongst institutions could serve as a potential solution to enhance the feasibility of DSME. CONCLUSIONS: This research highlighted the significant disparities and inadequacy of DSME within postgraduate orthodontic programmes in Thailand due to various challenges. Consequently, there is a compelling need to place greater emphasis on DSME and establish a national-level standardisation within orthodontic programmes. This effort is essential for enhancing the awareness and competency of orthodontists in the field of DSME.

Mandibular advancement devices used with morning occlusal guides for treating obstructive sleep apnea-changed incisor inclination and its associated factors.

PURPOSE: Mandibular advancement devices (MADs) effectively treat patients with obstructive sleep apnea (OSA). Although the use of morning occlusal guides (MOGs) along with MADs is recommended to prevent dental side effects, there is no evidence to support this. The aim of this study was to evaluate the change in incisor inclination in patients with OSA treated with MADs and MOGs, and to identify its predictive factors. METHODS: Patients with OSA who received MAD and MOG therapy and had a reduction in their apnea-hypopnea index greater than 50% were analyzed. Cephalometric measurements were performed at baseline and at a 1-year follow-up or longer to assess the dentoskeletal side effects of MAD/MOG treatment. Multivariable linear regression analysis was used to assess the association between the change in incisor inclination and the independent variables that may cause the observed side effects. RESULTS: Among 23 patients enrolled in the study, there was significant upper incisor retroclination (U1-SN: 2.83° ± 2.68°, U1-PP: 2.86° ± 2.46°; P < 0.05) and significant lower incisor proclination (L1-SN: 3.04° ± 3.29°, L1-MP: 1.74° ± 3.13°; P < 0.05). However, no significant skeletal changes were observed. Multivariable linear regression revealed that advancement ≥ 95% of the patients' maximal mandibular protrusion was associated with greater upper incisor retroclination. Increased treatment duration was also associated with increased upper incisor retroclination. No \measured variables were associated with the change in lower incisor inclination. CONCLUSIONS: Dental side effects occurred in patients who used MADs with MOGs. The amount of mandibular protrusion by MADs and treatment duration were predictive factors associated with upper incisor retroclination.

Effect of surgical mandibular setback on the occurrence of obstructive sleep apnea.

The aims were to assess the airway morphologic changes, and to evaluate sleep respiratory function and the occurrence of obstructive sleep apnea (OSA) after mandibular setback. Fifteen prognathism patients underwent bilateral sagittal split ramus (BSSRO) with or without maxilla surgery were grouped by distance of mandibular setback as group A (≤6 mm, n = 7) and group B (>6 mm, n = 8). Morphological changes were assessed using lateral cephalometric radiography and cone-beam computed tomography (CBCT) at preoperative (T0) and 6 months after surgery (T1). Sleep respiratory functions were evaluated using polysomonography. On lateral cephalometric radiography, group B showed significant decreased at Vp (p = 0.028) and PAS-p (p = 0.017). It also significant different between groups (p = 0.011 and p = 0.009 respectively). On CBCT, airway volume and AP width of airway, except Np, decreased in both groups but not significant different between groups. Only group A showed significant different between T0 and T1, cross-sectional area of Vp (p = 0.043), AP width of Vp (p = 0.043), Hp (p = 0.042), and PAS-t (p = 0.043). In group B, apnea hypopnea index increased at T1 (p = 0.043) and REM sleep differed between groups (p = 0.04). In conclusion, mandibular setback decreased the pharyngeal airway dimensions although no OSA occurred. It might be predisposing of OSA.