The effect of a modified functional appliance on obstructive sleep apnea

A computed tomographic evaluation of effect of mandibular advancement device at two different horizontal jaw positions in patients with obstructive sleep apnea

Statement of problem

Studies pertaining to the objective assessments of the efficacy of mandibular advancement device in patients with obstructive sleep apnea are scarce.

Purpose

The purpose of this clinical study was to evaluate the effect of MAD at two different horizontal positions of mandible on upper airway dimensions through computed tomography.

Material and methods

Twenty-nine consenting participants satisfying predetermined inclusion and exclusion criteria were enrolled and an adjustable two-piece MAD was fabricated at 50% maximum mandibular protrusion and after 4 weeks was adjusted to 70% protrusion. CT scans were obtained at baseline, 4 weeks after delivering MAD with 50% mandibular protrusion, and then after 4 weeks with 70% mandibular protrusion. Cross sectional area with diameters (lateral and anteroposterior) of upper airway was measured at three specific anatomic levels (retropalatal-RP, retroglossal-RG, and epiglottal-EG). Data were analyzed using the Student t-test for parametric analysis.

Results

Intragroup comparison revealed a statistically significant increase in lateral & anteroposterior dimensions as well as cross sectional area at all three anatomical levels at 4 weeks after MAD with 50% mandibular protrusion compared with baseline and 4 weeks after MAD with 70% mandibular protrusion compared with baseline. However, the difference between lateral and anteroposterior dimensions with MAD at 70% protrusion compared with MAD at 50% protrusion was not statistically significant. The difference between cross-sectional area was found to be statistically significant.

Conclusion

Mandibular advancement device at 70% mandibular protrusion is more effective compared with the device at 50% protrusion in relieving oropharyngeal obstruction seen in OSA.

The effect of gradually increased mandibular advancement on the efficacy of an oral appliance in the treatment of obstructive sleep apnea

STUDY OBJECTIVES

To analyze the effect of gradual increments of mandibular advancement on the treatment efficacy of mandibular advancement devices and identify determinants of effective and target protrusion for OSA.

METHODS

Patients were prospectively recruited. The mandible was titrated from 0 mm with a stepwise increment of 0.5 mm until the AHI was reduced to the lowest level. Rhinospirometry, rhinomanometry, and magnetic resonance imaging were used to observe the change of respiratory function and upper airway morphology.

RESULTS

Forty-two patients aged 41.5 ± 9.0 years participated. There was a dose-dependent relationship between mandibular protrusion and the AHI improvement rate, the success rate, and the normalization rate; the changing curves plateaued after approximately 70% of maximal mandibular protrusion was achieved. The correlation between AHI and mandibular protrusion became stronger as the severity of OSA increased. The target protrusion for patients with mild, moderate, and severe OSA was 3.5 ± 1.8 mm (38.6 ± 19.4% maximal mandibular protrusion), 5.8 ± 1.9 mm (62.9 ± 18.8% maximal mandibular protrusion), and 5.9 ± 2.2 mm (68.8 ± 15.6% maximal mandibular protrusion), respectively. Regression analysis revealed that the factors influencing effective and target protrusion included change of maximal lateral dimension of the total upper airway with mandibular advancement devices, mean lateral dimension of the oropharynx, and soft palate length. Further protrusion brought more lateral expansion of the velopharynx, whereas the change in nasal ventilation was not significant.

CONCLUSIONS

The dose-dependent effect of mandibular protrusion on reduction of AHI by mandibular advancement devices was nonlinear and became more pronounced with increased severity of OSA. The mandibular protrusion should be more personalized to each patient.

CLINICAL TRIAL REGISTRATION

Registry: Chinese Clinical Trial Registry; Name: Study of the Onset Point of Oral Appliance Treatment in Obstructive Sleep Apnea and Hypopnea Syndrome; URL: http://www.chictr.org.cn/showproj.aspx?proj=22291; Identifier: ChiCTR-IND-17013232.

A consideration of factors affecting palliative oral appliance effectiveness for obstructive sleep apnea: a scoping review

STUDY OBJECTIVES

This scoping review allows physicians, researchers, and others interested in obstructive sleep apnea to consider effectiveness of oral appliances (OAs). The intent is to improve understanding of OA effectiveness by considering morphologic interaction in patients with obstructive sleep apnea.

METHODS

Morphologic and biomechanical criteria for positional alterations of the mandible assessed success rates of OA appliances. Searches of databases (Medline, PubMed, The Cochrane Library, EBSCO) using terms: OA treatment effectiveness and positive and/or negative outcome predictors. Craniofacial predictors of OAs and obstructive sleep apnea biomechanical factors of anatomical traits associated with OA effectiveness were included. Databases searched radiographic cephalometric imaging for morphology/phenotypes and apnea-hypopnea index responses. Articles were excluded if title or abstract was not relevant or a case report. If the analysis did not report mean or standard deviation for apnea-hypoxia index, it was excluded. No language, age, or sex restrictions were applied.

RESULTS

Analysis of 135 articles included in searched literature indicated alterations in musculature and pharyngeal airway structure through OA use. These alterations were individually unpredictable with wide variability 61.81% ± 12.29 (apnea-hypoxia index mean ± standard deviation). Morphologic variations as predictors were typically weak and idiosyncratic. Biomechanical factors and wide variations in the metrics of appliance application were unclear, identifying gaps in knowledge and practice of OAs.

CONCLUSIONS

An integrated basis to identify morphologic and biomechanical elements of phenotypic expressions of sleep-disordered breathing in the design and application of OAs is needed. Current knowledge is heterogeneous and shows high variability. Identification of subgroups of patients with obstructive sleep apnea responding to OAs is needed.

Comparative assessment of changes in pharyngeal airway space in cases of obstructive sleep apnoea with a customized mandibular repositioning appliance - a clinical study

Objectives

The present study aims at evaluating the effects of a customized mandibular repositioning appliance on the pharyngeal airway, nocturnal sleep patterns, daytime discomfort and occlusal changes in established cases of adult obstructive sleep apnoea.

Material and Methods

Ten consecutive patients with a complaint of snoring and disturbed sleep were included in the study. The primary diagnosis was established by the Epworth sleepiness scale, clinical examination, history and subsequently the diagnosis was substantiated through assessment of the pharyngeal airway space on a lateral cephalogram and polysomnography. A customized mandibular repositioning appliance was used to advance the mandible sequentially every 6 months, using 4 sets of the appliance. Pre and post-treatment evaluations were performed to establish, effects and changes in the outcome of obstructive sleep apnoea.

Results

The study revealed significant increase in the mean pharyngeal widths of upper airway and velum dimension with antero-superior repositioning of hyoid bone. Epworth sleepiness scale score improved significantly from baseline with clinically evident change in daytime discomforts. Significant decline in the mean apnoea/hypopnea index, oxygen desaturation index, respiratory disturbance index, heart rate, snoring and a significant increase in mean oxygen saturation of arterial blood was observed. No evident change noticed in occlusion except lower incisor inclination.

Conclusion

The customized mandibular repositioning appliances are effective in the management of adult obstructive sleep apnoea with a significant improvement observed in the airway patency and polysomnography parameters with clinically non-significant effects on dental occlusion..

Oral Appliances for the Management of OSA: An Updated Review of the Literature

Oral appliances (OAs) are becoming increasingly recognized not only as an alternative to but also possibly as an adjunct treatment modality for OSA. Compared with CPAP, the gold standard therapy, OAs are less efficacious but are more accepted and tolerated by patients, which, in turn, may lead to a comparable level of therapeutic effectiveness. Different OA designs currently exist, and more are constantly emerging. Additionally, state-of-the-art technologies are being used in the fabrication of many; however, all the currently available OAs employ the same mechanism of action by targeting the anatomical component involved in the pathogenesis of the disease. Furthermore, the scope of use of OAs is expanding to include patients who are edentulous. For patients with OAs, the dentist is a member of an interdisciplinary team managing OSA, and constant communication and follow-up with the sleep physician and other team members is necessary for disease management.

Volumetric changes in pharyngeal airway in Class II division 1 patients treated with Forsus-fixed functional appliance: A three-dimensional cone-beam computed tomography study

Objective:

Recent years have witnessed a renewed interest to determine a quantifiable relationship between mandibular advancement performed with an orthodontic appliance and the resulting airway volume. The study was conducted to evaluate the volumetric changes in pharyngeal airway space using cone-beam computed tomography (CBCT) in Class II division 1 patients with retrognathic mandible treated by Forsus-fixed functional appliance and to compare them with their pretreatment findings.

Materials and Methods:

Thirty patients with Class II division 1 malocclusion of age group 10–17 years were selected randomly and evaluated for changes in pharyngeal airway volume with and without Forsus-fixed functional appliance. Patients in each group underwent CBCT scan of head and neck region at pretreatment stage and 6 months after the initial scan. Institutional approval for the project was obtained from the Ethical Committee. Volumetric changes of upper (oropharynx) and lower (hypopharynx) pharyngeal airways were measured on scanogram using computer software and intragroup comparisons were done.

Results:

There was a statistically significant increase in the volume of both hypopharynx and oropharynx and also total airway volume in patients treated with Forsus-fixed functional appliance. Three-dimensional reconstruction of the airway also demonstrates a considerable increase in pharyngeal airway space.

Conclusion:

Forsus-fixed functional appliance can be a promising appliance for improving pharyngeal airway volume in Class II division 1 patients with retrognathic mandible thus preventing obstructive sleep apnea and other respiratory problems in future. However, the long-term implications of this treatment modality need further consideration and a longer period of follow-up.

Anatomically Based Outcome Predictors of Treatment for Obstructive Sleep Apnea with Intraoral Splint Devices: A Systematic Review of Cephalometric Studies

AIMS

The aim of this review is to summarize data from the literature on the predictive value of anatomy-based parameters, as identified by cephalometry, for the efficacy of mandibular advancement devices (MAD) for the treatment of obstructive sleep apnea (OSA).

METHODS

Articles were initially selected based on their titles or abstracts. Full articles were then retrieved and further scrutinized according to predetermined criteria. Reference lists of selected articles were searched for any missed publications. The selected articles were methodologically evaluated.

RESULTS

Of an initial 311 references, 13 were selected that assessed correlations between polysomnographic and cephalometric variables. The majority of studies demonstrated a correlation between treatment effectiveness and features as determined by cephalometric analysis, such as the mandibular plane angle, hyoid bone distance to mandible, antero-posterior diameter of the maxilla, tongue area, cranial base, and soft palate.

CONCLUSIONS

The mandibular plane angle and the distance between hyoid bone and mandibular plane was found to have a predictive value for MAD effectiveness in OSA patients. However, the relative weak and somewhat inconsistent cephalometric data suggest that decisions based solely on these factors cannot be recommended, especially because an integrated analysis of other risk factors (e.g., age, sex, BMI) should also be taken into account.

An evaluation of two different mandibular advancement devices on craniofacial characteristics and upper airway dimensions of Chinese adult obstructive sleep apnea patients

OBJECTIVES

To evaluate the effects of two different mandibular advancement devices (MADs) on craniofacial characteristics and upper airway dimensions of Chinese adult patients with obstructive sleep apnea (OSA).

MATERIALS AND METHODS

Forty-five patients with OSA were recruited as part of a prospective randomized crossover trial for treatment with two different MADs. Lateral cephalograms were taken, and the Epworth Sleepiness Scale and the Sleep Apnea Quality of Life Index were completed at baseline.

RESULTS

The Apnea-Hypoxia Index was highly significantly reduced with the monoblock (P < .001) and significantly reduced with the twin block (P < .01). The monoblock demonstrated a superior result than the twin block (P < .05). A significant reduction was found in the distances between the hyoid bone to retrognathia (monoblock, P < .01; twin block, P < .001) as well as the distance between the hyoid bone and mandibular plane angle (P < .001). Furthermore, soft palate length increased significantly (P < .05) with both MADs. However, the changes did not differ in favor of either MAD.

CONCLUSION

Monoblock was the better MAD to improve OSA severity. No difference could be found in changes of subjective OSA indicators. Significant but similar cephalometric changes were observed, indicating both MADs alter the position of the surrounding musculature and improve upper airway patency. Therefore, the different design features of the MADs suggest an impact on some OSA indicators.

Efficacy of custom made oral appliance for treatment of obstructive sleep apnea

INTRODUCTION

oral appliance for the treatment of OSA is considered as an effective, low-risk alternative to CPAP. Demand for oral appliance increases as an alternative for those who cannot tolerate CPAP and refuse surgery. Oral appliances uses the traditional methods to advance the mandible thus modify the posture and their by enlarge the airway or otherwise reduce the collapsibility.

AIMS AND OBJECTIVES

The main objective of this study was to evaluate the efficacy of custom made oral appliance on sleep characteristics of OSA patients.

MATERIALS AND METHODS

Polysomnography was done on 15 patients of 24-60 years of age before (T1), and after the delivery of the custom made oral appliance (T2).

STATISTICAL ANALYSIS

Paired t tests were performed to determine the significance of change in the polysomnographic and cephalometric variables. P < 0.05 was considered as significant.

RESULTS

All patients with oral appliance showed an improvement in sleep parameters with an increase in sleep efficiency, and desaturation index with the use of oral appliance. ESS and cephalometric findings showed improvement in the sleep apnea in concordance with the sleep parameters.

CONCLUSIONS

Custom made oral appliance is a useful treatment option for improving quality of sleep and can be considered as an alternative treatment modality.

The status of cephalometry in the prediction of non-CPAP treatment outcome in obstructive sleep apnea patients

Obstructive sleep apnea syndrome (OSAS) is the most common sleep disordered breathing disorder (SDB) in adults and is characterized by a recurrent partial or complete collapse of the upper airway during sleep. This can be caused by many factors, sometimes interacting, such as skeletal malformations, soft tissue crowding, respiratory instability and the various effects of aging, obesity and gender that dictate craniofacial and upper airway anatomy. Research has demonstrated that the majority of patients exhibit at least one anatomical component such as retrognathia or a narrow posterior airway space that predisposes to the development of OSAS. Within the predisposing elements for OSAS many seem to point to anatomical characteristics. A standardized and relatively simple radiologic technique to evaluate anatomical craniofacial relationships is cephalometry. This has been used already for a long time in orthodontics, but is now gradually being introduced in OSAS treatment to envisage optimal treatment selection as well as to predict treatment outcomes. The purpose of the present review is to evaluate the contribution of cephalometry in the prediction of outcomes from OSAS treatments that depend on the upper airway morphology in their mechanisms of action such as oral appliances that advance the mandible as well as various surgical methods. In addition, an overview of imaging modalities and methods that currently are being used in cephalometric analysis in OSAS patients is provided. The findings indicate that isolated cephalometric parameters cannot be used to reliably predict treatment outcomes from mandibular advancement devices and surgical methods for OSAS. Extreme or outlying values of cephalometric parameters may rather be used as contra-indicators or 'red flags' instead of predictors.

Mandibular advancement appliances for the treatment of paediatric obstructive sleep apnea: a systematic review

OBJECTIVE

To evaluate the effectiveness of mandibular advancement appliances (MAAs) for treatment of pediatric obstructive sleep apnea (OSA).

METHODS

Several electronic databases (The Cochrane Database, EMBASE, Healthstar, MEDLINE, PubMed) were systematically searched, as well as a limited grey literature (Google Scholar) and manual searches. A health sciences librarian helped with the selection of Medical Subject Headings (MeSH), key words, and combinations of key words with truncations to account for any differences in controlled terminology in the different databases. Only studies that evaluated the effects of MAAs in children with OSA were pursued.

RESULTS

Only 4 articles satisfied all inclusion criteria. Selected studies were retrospective except one study that was a quasi-randomized clinical trial. High risk of bias (Cochrane Risk of Bias assessment) was judged in all included studies. Based on the limited available evidence use of MAAs in a POSA population may result in improvements in Apnea Hypopnea Index (AHI) scores. However complete normalization of AHI scores was not demonstrated. Heterogeneity in study designs and collected information precluded meta-analysis.

LIMITATIONS

There are significant weaknesses in the existing evidence due primarily to absence of control groups, small sample sizes, lack of randomization and short-term results. Determination of AHI scores with MAAs still in the mouth should be avoided.

CONCLUSIONS

The current limited evidence may be suggestive that MAAs result in short-term improvements in AHI scores, but it is not possible to conclude that MMAs are effective to treat pediatric OSA. Medium- and long-term assessments are still required.

Cephalometric evaluation of hyoid bone position and pharyngeal spaces following treatment with Twin block appliance

OBJECTIVE

To evaluate the position of hyoid bone in the subjects treated with Twin block appliance.

MATERIALS AND METHODS

The sample consisted of 40 Angle's Class II division 1 subjects treated with Twin block appliance. Lateral radiographs were taken before and after treatment. According to Schudy's facial divergence angle (SN-MP), the subjects were classified in to three groups: group I (hypodivergent, SN-MP: <31° (27°-30°), n=15), group II (normodivergent, SN-MP: 31°-34°, n=15), and group III (hyperdivergent, SN-MP: >34° (35°-38°), n=10). Lateral cephalograms were traced and analyzed manually. After measurements of variables, Student's t-test and one-way analysis of variance (ANOVA) were performed.

RESULTS

Post treatment with Twin block therapy, hyoid bone shifted significantly (P<0.01) forward in horizontal dimension in all three groups, although it was highest in group III. However, there was no significant difference amongst the groups. In vertical dimension, hyoid bone shifted in upward direction in all three groups; however, the shift was significant (P<0.01) only in group I and there was a significant difference between group I and rest of the two groups. Width of upper airway significantly (P<0.01) increased and ANB angle significantly (P<0.001) decreased in all three groups with forward movement of mandible.

CONCLUSIONS

After treatment with Twin block appliance, significant changes occurred in horizontal dimension (anterior displacement), which resulted in significant increase in width of upper pharynx in all three groups.

Cephalomteric changes in airway dimensions with twin block therapy in growing Class II patients

Introduction:

Myofunctional appliances are commonly used for correction of skeletal Class II malrelationship. These appliances influence craniofacial and nasopharyngeal dimensions.

Objectives:

The present study was done to evaluate changes in airway with twin block therapy.

Materials and Methods:

Cephalometric assessment of airway was done in 25 growing children in the age group of 11-13 years with Class II skeletal pattern. All the patients were treated with twin block appliance. Pre and post treatment lateral cephalograms were taken to evaluate the changes in different airway and craniofacial dimensions during the treatment period. The average treatment duration was 14.5 months.

Results:

Airway: A significant increase was observed in upper and lower pharyngeal width and area of bony nasopharynx. Craniofacial dimension: There was a significant increase in effective mandibular length, ramal length and mandibular plane angle. There was an increase in SNB angle, which resulted in decreased ANB angle.

Conclusion:

There was a definite improvement in airway dimension following twin block therapy

Efficacy of the Silensor for treating obstructive sleep apnea syndrome

INTRODUCTION

Although mandibular repositioning devices were found to be very effective for treating obstructive sleep apnea (OSAS), they can cause side effects such as temporomandibular joint disorder and occlusal deviation. A semi-rigid device with a low frequency of side effects, the Silensor, (Erkodent Gmbh, Tuttlingen, Germany) was reported previously. The purpose of this study is to determine whether the Silensor is effective for treating OSAS.

MATERIALS AND METHODS

Thirty-five OSAS patients (27 males and 8 females) who were treated with the Silensor were enrolled in this study. The mean age and body mass index of the patients were 52.2 years (23-72 years) and 24.5 kg/m(2) (19.3-31.6 kg/m(2)), respectively. The patients were classified into two groups based on the length of the apparatus connector: 0-2 or 3-4 mm. A polysomnography test was performed twice, at the first visit and after the improvement of subjective symptoms. These data were statistically analyzed using the Wilcoxon signed-rank test.

RESULTS

The apnea-hypopnea index significantly improved in all OSAS patients, the mild to moderate OSAS patients, severe OSAS patients, 0- to 2-mm group, and the 3- to 4-mm group (91.4 %; p < 0.01, 88.9 %; p < 0.01, 100 %; p < 0.05, 86.4 %; p < 0.01, 100 %; p < 0.01, respectively). The only side effects of the Silensor were broken apparatus and damage to the buccal mucosa.

DISCUSSION

The Silensor is useful for the treatment of OSAS. In particular, the Silensor is suitable for the first phase of OSAS treatment with oral appliances because the efficacy of the Silensor was equal to that of other oral appliances and had few side effects.

Airway and Craniofacial Changes With Mandibular Advancement Device in Chinese With Obstructive Sleep Apnoea

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. Key words: Lateral cephalogram, Mandibular advancement splint, Mandibular advancement device, Obstructive sleep apnoea, Polysomnogram

Predictors of obstructive sleep apnea-hypopnea treatment outcome

Oral appliance therapy is an alternative to continuous positive airway pressure (CPAP) for treating the obstructive sleep apnea-hypopnea syndrome. However, the ability to pre-select suitable candidates for either treatment is limited. The aim of this study was to assess the value of relevant variables that can predict the outcome of oral appliance and CPAP therapy. Fifty-one patients treated with oral appliance therapy and 52 patients treated with CPAP were included. Relevant clinical, polysomnographic, and cephalometric variables were determined at baseline. The predictive value of variables for treatment outcome was evaluated in univariate and multivariate analyses. The outcome of oral appliance therapy was favorable, especially in less obese patients with milder sleep apnea and with certain craniofacial characteristics (mandibular retrognathism in particular). Neither univariate nor multivariate analyses yielded variables that reliably predicted the outcome of CPAP. We conclude that the variables found in this study are valuable for pre-selecting suitable candidates for oral-appliance therapy.

Review of oral appliances for treatment of sleep-disordered breathing

Between 1982 and 2006, there were 89 distinct publications dealing with oral appliance therapy involving a total of 3,027 patients, which reported results of sleep studies performed with and without the appliance. These studies, which constitute a very heterogeneous group in terms of methodology and patient population, are reviewed and the results summarized. This review focused on the following outcomes: sleep apnea (i.e. reduction in the apnea/hypopnea index or respiratory disturbance index), ability of oral appliances to reduce snoring, effect of oral appliances on daytime function, comparison of oral appliances with other treatments (continuous positive airway pressure and surgery), side effects, dental changes (overbite and overjet), and long-term compliance. We found that the success rate, defined as the ability of the oral appliances to reduce apnea/hypopnea index to less than 10, is 54%. The response rate, defined as at least 50% reduction in the initial apnea/hypopnea index (although it still remained above 10), is 21%. When only the results of randomized, crossover, placebo-controlled studies are considered, the success and response rates are 50% and 14%, respectively. Snoring was reduced by 45%. In the studies comparing oral appliances to continuous positive airway pressure (CPAP) or to uvulopalatopharyngoplasty (UPPP), an appliance reduced initial AHI by 42%, CPAP reduced it by 75%, and UPPP by 30%. The majority of patients prefer using oral appliance than CPAP. Use of oral appliances improves daytime function somewhat; the Epworth sleepiness score (ESS) dropped from 11.2 to 7.8 in 854 patients. A summary of the follow-up compliance data shows that at 30 months, 56–68% of patients continue to use oral appliance. Side effects are relatively minor but frequent. The most common ones are excessive salivation and teeth discomfort. Efficacy and side effects depend on the type of appliance, degree of protrusion, vertical opening, and other settings. We conclude that oral appliances, although not as effective as CPAP in reducing sleep apnea, snoring, and improving daytime function, have a definite role in the treatment of snoring and sleep apnea.

A comparison of responders and nonresponders to oral appliance therapy for the treatment of obstructive sleep apnea

INTRODUCTION

This retrospective study compared cephalometric variables between responders and nonresponders to a titratable oral appliance (OA) in a group of subjects matched for sex, pretreatment age, and body mass index (BMI).

METHODS

Nine nonresponders as defined by an improvement in the apnea hypopnea index (AHI; <20%) and their individually matched responders were selected for this study. The difference in age for each matched pair was +/-5 years, and, for BMI, the difference was +/-15%. The pretreatment AHI was matched to the same category (moderate, >15 to < or =30; severe I, >30 to < or =45; and severe II, >45 AHI).

RESULTS

Middle and inferior airway space and oropharyngeal airway cross-sectional area were significantly larger in the nonresponders. Position of the mandible relative to the cervical spine was the only significant skeletal variable and was larger in nonresponders. Changes in BMI between the groups were statistically significant; the averages were a 2.9% increase in the nonresponders and a 0.5% decrease in responders. The wider airway in nonresponders might reflect an enhanced neuromuscular compensation while awake. The weight gain in nonresponders was relatively small, but it might have reduced the effectiveness of the OA.

CONCLUSION

When treating OSA patients with OA therapy, clinicians should pay particular attention to airway size and weight changes.

The relationship between severity of obstructive sleep apnoea/hypopnoea syndrome (OSAHS) and lateral cephalometric radiograph values: A clinical diagnostic tool

BACKGROUND

This prospective cross-sectional cohort study examined the relationship between radiographic anatomy and the severity of OSAHS. The severity of OSAHS can be measured subjectively in terms of the Epworth scale and objectively in terms of the apnoea/hypopnoea Index (AHI).

METHODS

121 lateral cephalometric radiographs were traced under uniform conditions and a series of 56 landmarks identified, from which 48 angular and linear measurements were made. Significant changes occurred when comparison of these measurements with the severity of OSAHS were made.

RESULTS

Body mass index (BMI), the maxillary-mandibular planes angle (MMPA) and the linear measurement between points 7 and 12, (the pharyngeal dimension measured from the tip of the soft palate to the corresponding horizontal point on the posterior pharynx), increased significantly with increasing severity of OSAHS as measured by the Epworth score. Overjet, lower lip length, and the distance from the hyoid bone to a point B on the mandible all increased significantly with increasing severity of OSAHS, as measured by the AHI. The hyoid bone was found to rotate counter clockwise as the severity of OSAHS increased, as a result the distance between the most anterior superior point on the hyoid bone and the maxillary plane was seen to decrease as severity of OSAHS increased in terms of AHI.

CONCLUSIONS

Some radiographic anatomical features show significant change as the severity of OSAHS increases and these features could be used in the identification of patients who have severe OSAHS. The Logit equation derived from the findings of this study may also be a useful clinical tool in predicting the likelihood of a subject suffering from severe OSAHS.

Condutas terapêuticas para tratamento da Síndrome da Apnéia e Hipopnéia Obstrutiva do Sono (SAHOS) e da Síndrome da Resistência das Vias Aéreas Superiores (SRVAS) com enfoque no Aparelho Anti-Ronco (AAR-ITO)

Os autores apresentam uma revisão da literatura referente às alternativas de tratamento cirúrgicas e não-cirúrgicas para a Síndrome da Apnéia e Hipopnéia Obstrutiva do Sono (SAHOS) e para a Síndrome da Resistência das Vias Aéreas superiores (SRVAS) com enfoque no princípio de ação e evolução dos aparelhos de avanço mandibular e, em particular, no mecanismo dinâmico de ação do Aparelho Anti-Ronco® (AAR-ITO).

Dental side-effects of mandibular advancement splint wear in patients who snore

OBJECTIVES

(a) To evaluate the longer term orthodontic side-effects of a Herbst mandibular advancement splint (MAS) in subjects with sleep disordered breathing. (b) To determine whether these are related to dental occlusion, degree of mandibular advancement or duration of appliance wear.

DESIGN

Retrospective, cohort study.

SETTING

Teaching hospital dental school.

PARTICIPANTS

Subjects with sleep disordered breathing who had been wearing an MAS regularly (a minimum of 5 h per night, six nights a week) for at least 2 years. Of 192 subjects who were identified, 30 fulfilled the inclusion criteria and were prepared to attend for review.

INTERVENTIONS

Dental casts were obtained and BMI and Epworth Sleepiness Scale scores recorded. These data were compared with those collected when the subject was first referred. A questionnaire was completed concerning MAS use, side-effects and any problems associated with the device.

MAIN OUTCOME MEASURES

Changes in incisor tooth position.

RESULTS

Median duration of MAS wear was 3.64 years. Small, statistically significant reductions in both vertical (-0.4 mm) and horizontal (-0.5 mm) overlap of the incisor teeth were found. This correlated with the degree of vertical opening of the MAS but was not related to the amount of mandibular protrusion or the duration of appliance wear.

CONCLUSIONS

Patients who are considered suitable for MAS should be warned that dental changes may occur. Thus referring surgeons should also be aware of this possibility.

Computerized tomographic evaluation of effects of mandibular anterior repositioning on the upper airway: a pilot study

STATEMENT OF PROBLEM

Snoring is related to narrowing of the upper airway. Treatment options for snoring may have potential side effects or discomfort which may not be tolerated by some patients. Mandibular advancement devices may cause fewer negative side effects than other treatment modalities and have been advocated as a treatment for snoring.

PURPOSE

The aim of the pilot study was to evaluate effects of the anterior mandibular positioner (AMP) on upper airway structures in patients with a snoring problem.

MATERIAL AND METHODS

Fifteen subjects with snoring problems as identified by spouses or close relatives were selected to complete a questionnaire related to snoring, respiratory symptoms, body mass index (BMI), and smoking habits. Computerized tomography (CT) scans were obtained with and without AMP device fabricated as a monoblock of acrylic resin. Measurements of the oropharynx including length (mm), cross-sectional area (mm2), and plane angle (degrees) were made using anatomic landmarks on standardized CT images and lateral scanograms. The data were statistically evaluated using Wilcoxon signed rank test (alpha=.05).

RESULTS

When the AMP was inserted, the cross-sectional area of the oropharynx increased by 60 mm2 on average (P<.05). A mean increase of 2.4 mm (range 1-7 mm) was observed in the posterior airway space on lateral scanograms (P<.005). The range for mandibular advancement was between 4 and 8 mm (mean 5.73 mm).

CONCLUSION

The primary effect of the AMP was enlargement of the oropharyngeal airway. Within the limitations of this pilot study, the results suggest that CT evaluation of the upper airway structures may be helpful in determining treatment modality and monitoring the effectiveness of the positioner.

Efficacy and co-morbidity of oral appliances in the treatment of obstructive sleep apnea-hypopnea: a systematic review

The Obstructive Sleep Apnea-Hypopnea Syndrome (OSAHS) is a common sleep-related breathing disorder characterized by repetitive obstructions of the upper airway during sleep. Modification of pharyngeal patency by Oral Appliance (OA) therapy has been suggested as an alternative to various treatment modalities for OSAHS. To determine the evidence base with respect to the efficacy and co-morbidity of OA therapy in OSAHS, we conducted a systematic review of the available literature. Primary outcome measures were the reduction in number of upper-airway obstructions and co-morbidity related to the craniomandibular or craniofacial complex, respectively. Eligible studies regarding efficacy were independently assessed by two assessors using a quality assessment scale. Effect sizes of methodologically sound studies were calculated. In identical interventions, effect sizes were pooled with the use of a random-effects model. Given the scarcity of controlled studies related to co-morbidity, appraisal was confined to a description of eligible studies. Sixteen controlled trials related to efficacy were identified. With respect to the primary outcome measure, OA therapy was clearly more effective than control therapy (pooled effect size, -0.96; 95% confidence interval [CI], -1.49 to -0.42) and possibly more effective than uvulopalatopharyngoplasty. Although patients generally preferred OA therapy, improvement of respiratory variables, such as the number of upper-airway obstructions, was usually better in Continuous Positive Airway Pressure (CPAP) therapy (pooled effect size, 0.83; 95% CI, 0.59 to 1.06). Moreover, specific aspects related to OA design may influence patient-perceived efficacy and preference. Twelve patient-series and one controlled trial related to co-morbidity were identified. Analysis of the data suggests that OA therapy may have adverse effects on the craniomandibular and craniofacial complex. Although CPAP is apparently more effective and adverse effects of OA treatment have been described, it can be concluded that OA therapy is a viable treatment for, especially, mild to moderate OSAHS. Controlled studies addressing the specific indication and co-morbidity of OA therapy are warranted.

Mandibular advancement devices in 630 men and women with obstructive sleep apnea and snoring: tolerability and predictors of treatment success

STUDY OBJECTIVE

To evaluate the tolerability and to find predictors of treatment success for an individually adjusted, one-piece mandibular advancement device in patients with snoring and obstructive sleep apnea.

DESIGN

Prospective study.

SETTING

Departments of Respiratory Medicine and Orthodontics, Umeå University.

PATIENTS

Six hundred nineteen of 630 patients (98%), who consecutively received treatment for sleep apnea and snoring from February 1989 to August 2000, were followed up. They had a mean apnea-hypopnea index of 16 (range, 0.0 to 76) and a mean body mass index of 28 (range, 19 to 42).

MEASUREMENTS

Interviews, questionnaires, and overnight sleep apnea recordings. Patients with an apnea-hypopnea index of >or=10 in the supine and/or lateral position were considered to have obstructive sleep apnea. A lateral apnea-hypopnea index of < 10, together with a supine apnea-hypopnea index of >or= 10, defined supine-dependent sleep apneas.

RESULTS

One hundred forty-eight of the 619 patients (24%) discontinued treatment. Female gender predicted treatment success, defined as an apnea-hypopnea index of < 10 in both the supine and lateral positions, with an odds ratio of 2.4 (p = 0.01). In the women, the odds ratios for treatment success were 12 for mild sleep apnea (p = 0.04), and 0.1 for complaints of nasal obstruction (p = 0.03). In the men, the odds ratios for treatment success were 6.0 for supine-dependent sleep apneas (p < 0.001), 2.5 for mild sleep apnea (p = 0.04), 1.3 for each millimeter of mandibular advancement (p = 0.03), and 0.8 for each kilogram of weight increase (p = 0.001).

CONCLUSIONS

The mandibular advancement device is recommended for women with sleep apnea, for men with supine-dependent sleep apneas defined by a lateral apnea-hypopnea index of < 10, and for snorers without sleep apnea. Men who increase in weight during treatment reduce their chance of treatment success and are advised to be followed up with a new sleep apnea recording with the device.

An individually adjustable oral appliance vs continuous positive airway pressure in mild-to-moderate obstructive sleep apnea syndrome

BACKGROUND

For the treatment of nonsevere obstructive sleep apnea syndrome (OSAS), mandibular advancement devices (MADs) are employed as an alternative to nasal continuous positive airway pressure (CPAP) therapy. However, very few specific data on the effectiveness of MADs in this group of patients are available. We therefore compared an individually adjustable intraoral sleep apnea device (ISAD) that permits movements of the lower jaw in three dimensions, with CPAP in the treatment of patients with an apnea/hypopnea index (AHI) < or = 30/h.

METHODS

In a randomized crossover study, 16 men and 4 women (mean +/- SD age, 56.5 +/- 10.2 years; body mass index, 31.2 +/- 6.4; AHI, 17.5 +/- 7.7/h) were treated for 6 weeks with each modality.

RESULTS

In the initial phase, a significant improvement in AHI (baseline, 17.5 +/- 7.7/h; ISAD, 10.5 +/- 7.5/h [p < 0.05]; CPAP, 3.5 +/- 2.9/h [p < 0.01]) and in breathing-related arousals (baseline, 8.9 +/- 6.1/h; ISAD, 3.7 +/- 3.3/h [p < 0.01]; CPAP, 1.4 +/- 1.6/h [p < 0.01]) was achieved with both modalities. Considering all 20 subjects, after 6 weeks of treatment, normalization of the respiratory parameters was seen only with CPAP. However, 30% of the patients had a lasting reduction in AHI to < 10/h with the ISAD also. The patients considered the ISAD to be easier to use (scale of 1 to 6: ISAD, 1.8 +/- 1.1; CPAP, 3.1 +/- 1.5 [p < 0.05]), and indicated greater utilization of the device in comparison with CPAP.

CONCLUSION

Even in patients with mild-to-moderate OSAS, CPAP is the more effective long-term treatment modality. In the individual case, the better compliance seen with the ISAD may be advantageous.

The effect of posture and a mandibular protruding device on pharyngeal dimensions: a cephalometric study

The objectives were to evaluate the impact of body posture on cephalometric measures and the level and the extent to which treatment with a mandibular protruding device (MPD) affects pharyngeal width. The study was composed of 77 patients: 50 were diagnosed with obstructive sleep apnea (OSA) and 27 snored. After each patient underwent a baseline medical (including a somnographic registration), dental and stomatognathic examination, an MPD that would protrude the mandible 75% of the maximal protrusion range was fabricated. In a radiographic examination, four cephalograms were taken: two in the upright position with and without the MPD and two in the supine position with and without the MPD. The cephalometric measures focused on the pharyngeal structures. MPD treatment significantly increased the relative pharyngeal area (at the level of the oropharynx and the hypopharynx) by a mean of +89.6 mm2 (P < 0.01) in the upright posture. The relative pharyngeal area, however, was reduced by more than 50% in the supine position compared with the upright position, independent of MPD treatment. In the supine position, compared with upright, most pharyngeal measures decreased significantly; the hyoid was significantly lower and displaced posteriorly, and the area of the velum increased by a mean of +201.2 mm2 (P < 0.001). We conclude that the MPD significantly increased most pharyngeal measures except the linear distance between the hyoid bone and the third vertebra and decreased the area of the velum.

Treatment of obstructive sleep apnea with the Karwetzky oral appliance

The aims of this retrospective study were to assess the effect of a Karwetzky mandibular protrusion appliance for treating patients with mild, moderate, and severe obstructive sleep apnea. Eighty-one of 116 patients (69.8%) suffering from obstructive sleep apnea were treated with an activator model according to Karwetzky. After 4 months (SD 4.0 months) treatment outcome was controlled by polysomnography. Therapeutic outcome depended on the severity of obstructive sleep apnea. The median apnea-hypopnea index decreased from 10.6 events/h (range 2.0-14.9) to 5.8 events/h (range 0.2-17.3, P<0.01) in the mild group, from 21.7 events/h (range 17.3-28.4) to 7.7 events/h (range 1.0-30.1, P<0.001) in the moderate group, and from 42.1 events/h (range 33.2-64.9) to 18.1 events/h (range 2.4-48.8, P<0.001) in the severe group. Sleep variables did not show consistent improvement except for a trend towards more REM sleep and slow-wave sleep. The numbers of retentive teeth did not statistically influence treatment efficacy. Comparing the pre- and post-treatment polysomnographic variables, it was found that the respiratory events rather than sleep stages were significantly reduced by the Karwetzky appliance investigated.

Therapeutic efficacy of an oral appliance in the treatment of obstructive sleep apnea: a 2-year follow-up

The purpose of this study was to investigate the long-term efficacy of an oral appliance, the Karwetzky activator, on respiratory and sleep parameters in patients with obstructive sleep apnea (OSA). Those selected for this study were 26 patients polysomnographically diagnosed with mild-to-moderate OSA. They were initially treated successfully with this appliance, as documented by a second polysomnographic study after 6 to 12 weeks. Further polysomnographic registrations 6 to 12 months and 18 to 24 months later were performed for each patient wearing the appliance. For 21 patients (81%), therapeutic efficacy was maintained; 5 patients (19%) showed a deterioration in respiratory parameters. We corrected this by adjusting the device in 2 patients. The mean apnea-hypopnea index decreased significantly from 17.8 events per hour at the baseline registration to 4.2 events per hour (P <.001) after 6 to 12 weeks of treatment. After 6 to 12 months, the apnea-hypopnea index was 8.2 events per hour. The index remained at this level 18 to 24 months later, with 8.3 events per hour. Mean oxygen saturation was not improved with the activator, but the number of desaturations had decreased at the 6-to-12 week review. Again, the improvement declined with time, but the number of oxygen desaturations was still significantly decreased at 18 to 24 months (P <.01). Although the respiratory parameters remained statistically improved throughout the study (P <.01), sleep architecture did not change statistically. In most patients, therapeutic efficacy was maintained at the 2-year follow-up, although there was a tendency for effectiveness to fall over time. We concluded that the Karwetzky activator may be an effective treatment alternative for patients with mild-to-moderate OSA, but therapy requires diligent and regular polysomnographic follow-ups. Further long-term studies are needed to assess the continued efficacy of this oral appliance in treating OSA.

Supine Cephalometric Analyses of an Adjustable Oral Appliance Used in the Treatment of Obstructive Sleep Apnea

OBJECTIVE: To investigate the effects of the Klearway(TM) appliance on the upper airway in patients with obstructive sleep apnea (OSA) in the supine position. METHODS: Sixteen subjects (12 males and 4 females) were recruited on the basis of baseline polysomnography with a documented Apnea and Hypopnea Index (AHI) >15 per hour. A second overnight sleep study was performed for each subject with the appliance in place. Baseline supine cephalometry was performed for each subject before the initial insertion of the appliance, and follow-up supine cephalometry was undertaken with the appliance in place. RESULTS: The polysomnographic variables improved significantly, and the mean changes in overbite and overjet were 5.15 mm and 6.26 mm after insertion of the Klearway(TM) appliance. The supine sagittal cross-sectional areas of the pharynx and the tongue significantly increased, while the linear distance from the hyoid position to the mandibular plane or the RGN-C3 line significantly decreased after insertion of the appliance. The ratio of the vertical pharyngeal length to the sagittal cross-sectional area of nasopharynx or tongue decreased significantly. When the subjects were evaluated on the basis of the after-insertion AHI, the group with good response (n = 11) was found to be significantly younger than the group with the poor response (n = 5). Similarly, the good responders revealed less prominent chins, larger tongue heights, and an increase in hypopharyngeal sagittal cross-sectional area after insertion of the appliance. There was a significant correlation between the improvement in AHI (%) and the supine middle airway space (r = -0.52, p < 0.05). CONCLUSION: The mechanical effect of the Klearway(TM) appliance on the upper airway and the stabilization of jaw posture may be important determinants of the efficacy of the appliance.

Cephalometric and physiologic predictors of the efficacy of an adjustable oral appliance for treating obstructive sleep apnea

The purpose of this study was to investigate whether any physiologic or cephalometric parameters could be used to predict the efficacy of an adjustable mandibular advancement appliance for treating obstructive sleep apnea (OSA). Forty-two male and 5 female patients with OSA were recruited on the basis of baseline polysomnography with a documented Apnea and Hypopnea Index (AHI) greater than 15 per hour. Repeat polysomnography was performed with the appliance in place. Baseline cephalometry was performed for each patient, and follow-up cephalometry was completed for 19 of the subjects. The subjects were divided into 3 groups on the basis of the degree of change in the AHI with oral appliance therapy: good response (> 75% decrease in AHI), moderate response (25% to 75% decrease in AHI), and poor response (< 25% decrease in AHI). Patients with a good response were younger and had smaller upper airways. In a linear regression analysis, the change in AHI (%) was associated with physiologic (age and body mass index), cephalometric (overjet, height of the maxillary molars, vertical height of the hyoid bone), and airway variables. However, changes in either overbite or overjet were not related to changes in any of the polysomnographic variables for the 19 subjects. A stepwise regression analysis revealed a better treatment response with the adjustable mandibular advancement appliance in patients who were younger and had a lower body mass index, a longer maxilla, a smaller oropharynx, a smaller overjet, less erupted maxillary molars, and a larger ratio of vertical airway length to the cross-sectional area of the soft palate.

Cephalometric and polysomnographic analyses of functional magnetic system therapy in patients with obstructive sleep apnea

The therapeutic effect of a functional magnetic system on obstructive sleep apnea and the system's operating mechanism have not been examined. Two hypotheses are postulated: a functional magnetic system increases the size of the oral cavity airway passage, or it increases the pharyngeal space. Twenty-eight patients with mild-to-moderate obstructive sleep apnea were examined; 10 patients (9 men and 1 woman; aged, 50.5 +/- 2.6 years) met the study criteria. After baseline nocturnal polysomnography and daytime tiredness self-evaluation, a functional magnetic system was inserted. The functional magnetic system is a mandibular repositioning appliance that uses a pair of attractive magnets (Sm2Co17), placed opposite each other in the jaws, which results in an advancement-to-opening ratio of 1:2. After 8 weeks of functional magnetic system treatment, polysomnography, daytime tiredness, and nighttime snoring were evaluated, and cephalogram radiographs with and without the appliance were taken. It was found that the respiratory disturbance index decreased significantly; minimal oxygen saturation increased significantly, reaching a normal value; day time tiredness improved; snoring declined; the oral cavity anterior region increased significantly, and the pharyngeal airway passages did not change. Reduction in the respiratory disturbance index and enlargement of the anterior oral cavity area were highly and significantly correlated. In conclusion, the functional magnetic system is a reliable mandibular repositioning appliance that has no apparent adverse effects. A functional magnetic system operates by increasing the anterior region of the oral cavity, mainly vertically, with no change in the posterior oral cavity region and pharyngeal airway passages.

Mandibular advancement device in patients with obstructive sleep apnea : long-term effects on apnea and sleep

STUDY OBJECTIVES

To evaluate the long-term effects on apneas and sleep and the tolerability of a mandibular advancement device in patients with obstructive sleep apnea.

DESIGN

Prospective study.

SETTING

Department of Respiratory Medicine, University Hospital, Umeå, Sweden.

PATIENTS

Thirty-three consecutively treated patients.

INTERVENTIONS

Individually adjusted mandibular advancement devices.

MEASUREMENTS AND RESULTS

Polysomnographic sleep recordings on 1 night without the device and 1 night with the device were performed after 0.7 +/- 0.5 years (mean +/- SD) and after 5.2 +/- 0.4 years from the start of treatment. Nineteen of the 33 patients experienced a short-term satisfactory treatment result with an apnea-hypopnea index of < 10 events per hour and a satisfactory reduction in snoring. Fourteen patients were regarded as being insufficiently treated with the device. Seventeen of the short-term satisfactorily treated patients (90%) and 2 of the remaining patients continued treatment on a long-term basis. The apnea-hypopnea index was reduced by the device from 22 +/- 17 to 4.9 +/- 5.1 events per hour (p < 0.001) in these 19 long-term treatment patients, which did not differ from what was found at the short-term follow-up visits in these patients. Patients with their devices replaced or adjusted experienced a better long-term effect than patients still using their original devices (p < 0.05).

CONCLUSIONS

The long-term effect and tolerability of a mandibular advancement device are good in patients who are recommended the treatment on the basis of a short-term sleep recording, provided that the device is continuously adjusted or replaced with a new one when needed. A short-term follow-up is valuable in the selection of patients who will benefit from long-term treatment with a mandibular advancement device.

Evaluation of the Herbst Mandibular Advancement Splint in the management of patients with sleep-related breathing disorders

Sleep-related breathing disorders such as snoring and obstructive sleep apnoea syndrome are the cause of significant social disruption and hypersomnolence. Several intraoral appliances for the treatment of these disorders have been described, especially where nasal continuous positive airway pressure is poorly tolerated. Mandibular Advancement Splints, such as the Herbst splint used in this study can also be offered to patients with mild to moderate sleep apnoea and simple snorers. The success and compliance rate noted in the literature are quite diverse. Few side-effects have been reported. We therefore undertook this study to assess: (1) the compliance; (2) the effectiveness; and (3) the side-effects in the long- and short-term. All patients for whom a Herbst splint had been prescribed in the last 18 months were sent a postal questionnaire regarding the above mentioned issues. In all, 179 questionnaires were posted and on analysis of the 132 returned it was noted that 82% of splints were worn and 88% of patients found the device to be effective. The long-term side-effects were minimal. In addition objective assessment on 10 patients with and without a jaw-retaining device was also obtained. We conclude that the Herbst Mandibular Advancement Splint is a justifiable option in selected subjects with sleep-related breathing disorders.

Effects of a mandibular repositioner on obstructive sleep apnea

The purpose of this study was to investigate the effects of a mandibular repositioner on airway, sleep, and respiratory variables in patients with obstructive sleep apnea. Twenty-two patients selected for this study were confirmed with a diagnosis of obstructive sleep apnea based on initial nocturnal polysomnography. The patients were fitted with a mandibular repositioner designed to hold the mandible anteroinferiorly. Six months later, an outcome polysomnographic study was undertaken for each patient with the appliance in place. Lateral cephalometric radiographs in the upright position were also obtained before and after 6 months of treatment. The respiratory disturbance index decreased in 21 of the 22 patients with the appliance in place. The mean respiratory disturbance index of the 22 patients decreased significantly from 40.3 to 11.7 events per hour (P <.01). Some 59.1% of subjects were considered a treatment success with follow-up respiratory disturbance index < 10 events per hour. The mean minimum blood oxygen saturation level during sleep also improved significantly from 73.4% to 81.3% (P <. 01). The mandibular repositioner was constructed to position the mandible at 75% of the maximal mandibular advancement and with a 7 mm opening between the upper and lower incisors, and no aberrant effect on temporomandibular joint was noted. The retropalatal airway space increased and the cross-sectional area of the soft palate and the vertical distance of the hyoid bone to the mandibular plane decreased significantly. The tongue posture became significantly flatter. A significant linear correlation was found between the reduction in apnea index and specific craniofacial skeletal structures (length of anterior cranial base, mandibular plane angle, and upper to lower facial height ratios, P <.05). Subjects with a smaller reduction in apnea index tended to have shorter anterior cranial bases, steeper mandibular planes, and smaller upper to lower facial height ratios. We conclude that a mandibular repositioner may be an effective treatment alternative for obstructive sleep apnea and that a reduction in the frequency of apneic episodes is mainly attributed to the effects of the appliance on oropharyngeal structures.

Obstructive sleep apnoea: multiple comparisons of cephalometric variables of obese and non-obese patients

BACKGROUND

Pathogenesis of obstructive sleep apnoea (OSA) is complex and not yet fully understood. Several factors contribute to OSA severity. Obesity is believed to play an important role. Nevertheless, not all OSA patients are obese. Therefore, the different features that cause nocturnal upper airway obstruction in obese and non-obese OSA patients could be expected.

PURPOSE

To investigate the different components of cervico-craniofacial skeletal and upper airway soft tissue morphology among obese OSA, non-obese OSA patients and the controls.

PATIENTS

One hundred male OSA patients were classified into two groups on the basis of body mass index (BMI) as obese (BMI > or = 30 kg/m2) and non-obese (BMI < 30 kg/m2). Consequently, 57 obese and 43 non-obese OSA patients were examined and compared with a control group of 36 healthy males.

STUDY DESIGN

A comprehensive cephalometric analysis of cervico-craniofacial skeletal and upper airway soft tissue morphology was performed. Sixty-eight cephalometric variables were compared among the three groups by one way analysis of variance with Bonferroni's test.

RESULTS

Both OSA groups had aberrations of cervico-craniofacial skeletal as well as upper airway soft tissue morphology when compared with the controls. These anatomic deviations were confined to cervico-craniofacial skeletal structures in the non-obese OSA patients, whereas the obese OSA patients had more abnormalities in the upper airway soft tissue morphology, head posture and position of the hyoid bone.

CONCLUSION

The findings imply that there should be different treatment regimens for the two subgroups of OSA patients. Cephalometric analysis together with various considerations of BMI is highly recommended as one of the most important tools in diagnosis and treatment planning for OSA patients.

Effects of a mandibular advancement device for the treatment of sleep apnea syndrome and snoring on respiratory function and sleep quality

In this study the fabrication of a simplified mandibular advancement device for sleep apnea syndrome was described. Its effect on respiratory function and sleep quality variables was evaluated polysomnographically in 256 patients with sleep apnea syndrome and snoring. Polysomnographic recordings were performed twice, before and after insertion of the oral appliance. The mean apneahypopnea index (AHI) decreased significantly (p < 0.0001) with the appliance to 18.2 from 43.2 without it. Responders defined by AHI < 10 were 54% and those defined as a 50% decrease of AHI were 66%. Oxygen saturation, duration of apnea, sleep efficiency, and total arousal were improved significantly after treatment without major side effects. The device improved significantly the respiratory function and sleep quality in patients with sleep apnea syndrome. Compliance was about 90% followed for 2.5 years. This appliance offers some advantages over other therapies because it is noninvasive, easy to fabricate, and well accepted by patients.

Dose-dependent effects of mandibular advancement on pharyngeal mechanics and nocturnal oxygenation in patients with sleep-disordered breathing

STUDY OBJECTIVES

To examine dose-dependent effects of mandibular advancement on collapsibility of the passive pharynx and sleep-disordered breathing (SDB).

DESIGN

Prospective, randomized study.

SETTING

University hospital.

PATIENTS

Thirty-seven adult patients with SDB.

INTERVENTIONS

Oral appliances with 2-, 4-, and 6-mm advancement of the mandible.

MEASUREMENTS AND RESULTS

Overnight oximetry was performed with and without oral appliances. Each 2-mm mandibular advancement coincided with approximately 20% improvement in number and severity of nocturnal desaturations. Percentages of patients producing a > 50% improvement rate of the number of desaturations were 25%, 48%, and 65% with use of oral appliances with 2-, 4-, and 6-mm mandibular advancement, respectively. Static pharyngeal mechanics were evaluated in six completely paralyzed patients with SDB under general anesthesia with and without the oral appliances. Advancement of mandibular position was found to produce dose-dependent closing pressure reduction of all pharyngeal segments. Normalization of nocturnal oxygenation was associated with negative closing pressure, especially at the velopharynx.

CONCLUSIONS

We conclude that improvement of both nocturnal oxygenation and pharyngeal collapsibility significantly depends on the mandibular position.