Does the degree of advancement during functional appliance therapy matter? (65/135)

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Influence of nasal resistance on oral appliance treatment outcome in obstructive sleep apnea. (66/135)

It has been recognized that nasal airway resistance (NAR) is elevated in patients with OSA. However, little is known regarding the influence of nasal resistance on mandibular advancement splint (MAS) treatment outcome in OSA patient. We hypothesized that nasal resistance differs between MAS responders and nonresponders and therefore may influence treatment outcome. Thirty-eight patients with known OSA underwent polysomnography while wearing a custom-made MAS. Treatment outcome was defined as follows: Responders (R) > or =50% reduction in AHI, and Nonresponders (NR) as <50% reduction in AHI. NAR was measured using posterior rhinomanometry in both sitting and supine positions, with and without MAS. The mean AHI in 26 responders was significantly reduced from 29.0 +/- 2.9/h to 6.7 +/- 1.2/h; P < 0.01). In 12 nonresponders there was no significant change in AHI (23.9 +/- 3.0/h vs 22.0 +/- 4.3/h; P=ns). Baseline NAR was significantly lower in responders in the sitting position compared to nonresponders (6.5 +/- 0.5 vs 9.4 +/- 1.0 cm H2O; P < 0.01). There was no significant change in NAR (from baseline) with MAS in either response group while in the sitting position, but in the supine position NAR increased significantly with MAS in the nonresponder group (11.8 +/- 1.5 vs. 13.8 +/- 1.6 cm H2O/L/s; P < 0.01). Logistic regression analysis revealed that NAR and BMI were the most important predictive factors for MAS treatment outcome. These data suggest that higher levels of NAR may negatively impact on treatment outcome with MAS.  (+info)

Mandibular advancement appliance for obstructive sleep apnoea: results of a randomised placebo controlled trial using parallel group design. (67/135)

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Stability of hard tissue profile after mandibular setback in sagittal split osteotomies: a longitudinal and long-term follow-up study. (68/135)

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Sleep apnea and mandibular advancement device. Revision of the literature. (69/135)

Sleep apnea and hypopnea syndrome (SAHS) is a disorder characterized by intermittent and repetitive obstruction of the upper airway provoking pharyngeal collapse. It is characterized clinically by a triad of daytime hypersomnia, snoring and pauses in breathing during sleep that are normally reported by the partner. Polysomnography is the chosen method for diagnosing this pathology. Patients with this disorder tend to have the following dental and orofacial signs: a retrognathic jaw, a narrow palate, a wide neck, deviation of the nasal septum and relative macroglossia, among others. Dentists should be ready to evaluate the risk-benefit of certain dental treatment options for this public health problem. The treatment of this problem will depend on its severity, with one of the options being the Mandibular Advancement Device (MAD) that is used especially in the treatment of slight or moderate SAHS and in the treatment of snoring, with results that are occasionally very successful. The objective of this study is to carry out an up-to-date literature review of SAHS and to evaluate the role of the dentist when faced with this pathology.  (+info)

Airway and craniofacial changes with mandibular advancement device in Chinese with obstructive sleep apnoea. (70/135)

INTRODUCTION: The objective of this study was to investigate whether a reduction of obstructive sleep apnoea (OSA) severity is associated with significant airway and craniofacial changes with mandibular advancement device (MAD) in Chinese subjects. MATERIALS AND METHODS: A total of 14 Chinese subjects (8 males, 6 females) diagnosed with OSA by overnight polysomnography (PSG), were fitted with the MAD. The mean +/- standard deviation baseline apnoea-hypopnoea index (AHI) was 38.4 +/- 17.2 and minimum arterial oxygen saturation (SaO2) was 75.5 +/- 11.1%. The second lateral cephalogram was taken (wearing the MAD) after the second PSG. The second PSG was indicated when symptoms have improved as shown by the Epworth Sleepiness Score and sleep questionnaire after wearing the MAD for 1 month. Comparison of cephalometric variables was done to evaluate the effects of the MAD on the upper airway and anatomical variables. Pre-treatment versus post-treatment variables were compared using Wilcoxon signedrank test to determine the statistical significance at the 5% levels. The changes in airway variables were correlated with the changes in AHI using the Spearman correlation test. RESULTS: At the second polysomnogram, AHI was significantly reduced to 10.9 +/- 14.7. Minimum SaO2 was significantly increased to 86 +/- 8.4%. Mean airway dimension was significantly increased at the nasopharyngeal area from 22.7 +/- 3.0 mm to 24.8 +/- 2.1 mm. The distance of the hyoid bone to the mandibular plane was significantly reduced with the MAD from a mean of 21.2 +/- 5.7 mm to 13.9 +/- 7.0 mm (P <0.05). This reduction of the distance of the hyoid bone to the mandibular plane was significantly correlated with the reduction in the AHI. CONCLUSION: An increase in the nasopharyngeal airway and reduction of the distance of the hyoid bone to the mandibular plane was observed for this sample of Chinese OSA subjects. This study forms the baseline for future studies on the effects of MAD on the airway and craniofacial structures in a larger sample.  (+info)

Effect of orthognathic surgery on the posterior airway space (PAS). (71/135)

Orthognathic surgery has been used regularly to treat dentofacial deformities. The surgical procedures affect both the facial appearance as well as the posterior airway space (PAS). Our current literature indicates that setback procedures produce an inferior repositioning of the hyoid bone and posterior displacement of the tongue and the soft palate. These movements cause anteroposterior and lateral narrowing of the PAS. Most authors agree that these effects are permanent. The PAS changes in turn produce an adaptive posturing, with an increased craniocervical angle to open up the PAS. Even though most patients do not display snoring and obstructive sleep apnoea (OSA) post-surgery, there is certainly an increased possibility in patients with already compromised airways. Therefore, patients who are undergoing orthognathic surgery should be screened for excessive daytime somnolence, snoring, increased body mass index (BMI) and medical conditions related to OSA and sent for an overnight polysomnography (PSG) if OSA is suspected. Then the proposed treatment plan may be modified according to the risk of potential airway compromise or even to improve it. Conversely, advancement of the maxilla and mandible causes widening of the airway in both the anteroposterior and lateral dimensions. This effect would translate to better airflow and decreased airway resistance. This is supported by the evidence showing high success rates when orthognathic surgery, especially maxillomandibular advancement (MMA), is utilised to treat OSA.  (+info)

Short-term effects of oral appliances with equal bite-raising distance but with varying protrusions on occlusal force, contact area and load center. (72/135)

The purpose of this study was to demonstrate how short-term wearing of an oral appliance (OA) with equal bite-raising distance but with varying protrusions affects occlusal force, contact area and load center. Twelve young healthy volunteers participated. With the appliance, the mandible was protruded 0%, 45%, 60% and 75% of maximum protrusion capacity, with 10 mm bite-raising between the first molars. The occlusal force, contact area and load center at maximum voluntary clenching were measured before wearing the OA, at 1 h, 3 h and 6 h during wearing, and 1 h after removal. When compared to the values before wearing the OA, occlusal force was significantly lower at 1 h, 3 h and 6 h during wearing in the case of no mandibular protrusion, and at 3 h and 6 h after for 45%, 60% and 75% of maximum mandibular protrusion (P < 0.05). Occlusal contact area was significantly smaller at 1 h and 6 h during wearing in the case of no protrusion, and at 6 h during wearing in the case of 45% of maximum protrusion (P < 0.05). There was a tendency for anterior shift in the location of the occlusal load center at 3 h and 6 h during wearing of the OA with any level of maximum protrusion. No significant change in these three measurements was found at 1 h after removal of the OA. The present study demonstrated that wearing an OA had only a marginal and transient influence on oral functions when their changes were compared before and after wearing the OA.  (+info)