Impact of sleep nasendoscopy on the outcome of mandibular advancement splint therapy in subjects with sleep-related breathing disorders.

AIM: To evaluate the impact of positive sleep nasendoscopy, with simultaneous mandibular advancement, on the outcome of mandibular advancement splint therapy in 120 subjects with sleep-related breathing disorders. METHODOLOGY: Overnight polysomnography and sleep nasendoscopy were performed prior to splint therapy. Follow-up sleep studies, with the appliance in situ, were undertaken for those patients with obstructive sleep apnoea. Subjective outcome measures assessed daytime sleepiness and snoring. RESULTS: One hundred and seven (89 per cent) subjects completed the study. Follow-up sleep studies confirmed the efficacy of treatment, with patients showing a mean reduction in apnoea/hypopnoea index (from 18.9 to 4.9, p<0.001), Epworth sleepiness scale scores (from 11 to seven, p<0.001) and partner-recorded snoring scores (from 14 to eight, p<0.001). CONCLUSION: Sleep nasendoscopy, with concomitant mandibular advancement to mimic the treatment effect, could be of prognostic value in determining successful mandibular advancement splint therapy.

Sleep nasendoscopy as a predictor of treatment success in snorers using mandibular advancement splints.

This study assessed the effect on the upper airway during sleep nasendoscopy of mimicking the action of a mandibular advancement splint. Twenty-seven subjects with a diagnosis of sleep-disordered breathing were referred for mandibular advancement splint therapy following sleep nasendoscopy. Sleep nasendoscopy was repeated for all subjects with, and without, the appliance in situ. Follow-up sleep studies with a mandibular advancement splint in situ were undertaken for 19 individuals with significant obstructive sleep apnoea. With the mandibular advancement splint, subjective snoring levels and airway patency improved as predicted in all but one individual. Residual palatal flutter was predicted for five subjects and occurred in eight individuals. Follow-up sleep studies showed highly statistically significant reductions in median apnoea-hypopnoea index (from 28.1 to 6.1, p < 0.001). Mimicking the action of a mandibular advancement splint during sleep nasendoscopy helps considerably in the patient selection process for this form of treatment.

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.

A comparison of the Twin Block and Herbst mandibular advancement splints in the treatment of patients with obstructive sleep apnoea: a prospective study.

This prospective, randomized, crossover study of 16 patients with obstructive sleep apnoea (OSA) [12 males, four females; median body mass index (BMI) 29.2 kg/m(2) (range 23.8-51.1); median age 44.8 years (range 24.0-68.4)] analysed the efficacy of the Twin Block (TB) in relation to the Herbst appliance as a mandibular advancement splint (MAS). Each subject was fitted with a TB and Herbst MAS in a random order with a washout period of 2 weeks between appliances. Once each patient was subjectively happy with the performance of each appliance, questionnaires and a visual analogue scale (VAS) were used to determine differences in snoring, daytime sleepiness, quality of life, side-effects of the appliances and patient preference. All patients underwent overnight domiciliary sleep recordings prior to and after fitting each appliance in order to objectively assess sleep quality in terms of the apnoea-hypopnoea index (AHI), snoring frequency and arterial oxygen saturation. The results suggested that there was no difference in the treatment performance of the TB and Herbst MAS for AHI (P = 0.71), snoring frequency (P = 0.49), arterial blood oxygen saturation (P = 0.97), quality of life and side-effects. The Herbst MAS proved to be the more effective appliance for reducing daytime sleepiness (P = 0.04) and was the more popular appliance among the patients. Side-effects with both appliances were minor and improved in the longer term. The TB MAS represents a viable alternative to the Herbst MAS in the treatment of patients with OSA.

Non-apneic snoring and the orthodontist: the effectiveness of mandibular advancement splints.

OBJECTIVE: Non-apneic snoring is a very common problem, which impacts on all family members. Oral appliances have been used in the management of snoring. These posture the mandible forward during sleep, opening the airway and so reducing the potential for noise generation. This articles aims to objectively evaluate the effectiveness of mandibular advancement splints (MAS) in non-apneic snorers. DESIGN: Prospective clinical trial. SETTING: University Dental Hospital and School. SUBJECTS AND METHODS: 35 consecutively referred adults with proven non-apneic snoring. INTERVENTIONS: Subjects were fitted with a removable, adjustable Herbst MAS. MAIN OUTCOME MEASURES: Questionnaires determined changes in snoring incidence, daytime tiredness, any side effects and their duration. Eleven subjects completed overnight domiciliary sleep recordings of oxygen saturations, pulse rates and sound profile, before and 1 month after fitting the MAS. RESULTS: The questionnaires and sleep recordings suggested that the MAS significantly reduced snoring incidence (p<0.05) and improved sleep quality. Daytime tiredness, as assessed by the Epworth Sleepiness Scale, was significantly reduced (p<0.001). Initial side effects of muscular and TMJ discomforts were mostly resolved after 1 month of appliance wear. CONCLUSIONS: Use of a MAS improves snoring incidence and sleep quality in most patients with non-apneic snoring.

Non-apneic snoring and the orthodontist: radiographic pharyngeal dimension changes with supine posture and mandibular protrusion.

OBJECTIVE: To evaluate the radiographic changes that occur in the pharynx and surrounding structures with alteration of posture from the upright to the supine position and the effect that mandibular protrusion whilst supine has on these dimensions. DESIGN: Prospective cephalometric study. SETTING: University Dental Hospital and School. SUBJECTS AND METHOD: This prospective study involved 35 consecutively referred adults with proven non-apneic snoring. Lateral skull radiographs were obtained with the subjects upright in occlusion, supine in occlusion and supine with the mandible protruded to the maximum comfortable position. Radiographs were traced and digitized, and the pharyngeal dimensional changes and hyoid position were examined. Males and females were examined separately. RESULTS: Radiographic pharyngeal dimensions were changed with altered posture, resulting in significant reductions in the minimum post-palatal (p<0.01) and post-lingual (p<0.05) airway measurements in the supine position. Mandibular protrusion whilst in the supine position produced increases in the functioning space for the tongue. CONCLUSION: A supine posture results in significant reductions in pharyngeal airway measurements of non-apneic snorers. Mandibular protrusion whilst in the supine position produces an increase in the functioning space for the tongue.

Mandibular advancement splints and continuous positive airway pressure in patients with obstructive sleep apnoea: a randomized cross-over trial.

This prospective, randomized, cross-over trial was designed to compare the efficacy of a mandibular advancement splint (MAS) with that of nasal continuous positive airway pressure (nCPAP) in patients with obstructive sleep apnoea (OSA). Twenty-four patients (20 males and four females) with mild to moderate OSA (AHI between 10 and 49 events per hour) were enrolled in the study. Each patient used both MAS and nCPAP, with the initial therapy being allocated at random. Treatment periods lasted for two months with a two-week wash-out interval between. Polysomnography was performed prior to the study and after each clinical intervention. Patient and partner questionnaires were used to assess changes in general health and daytime somnolence. The AHI decreased from 22.2 to 3.1 using nCPAP, and to 8.0 using the MAS (P < 0.001 for both devices) and there was no statistically significant difference between the two treatments. The Epworth Sleepiness Score (ESS) fell from 13.4 to 8.1 with nCPAP, and to 9.2 with MAS (P < 0.001), again with no differences between the use of MAS or nCPAP. The questionnaire data showed an improvement in general health scores (P < 0.001) after both treatments, but daytime sleepiness only improved significantly using nCPAP (P < 0.001). Despite this, 17 out of the 21 subjects who completed both arms of the study preferred the MAS. The splints were well tolerated and their efficacy suggests that the MAS may be a suitable alternative to nCPAP in the management of patients with mild or moderate OSA.

Long-term use of mandibular advancement splints for snoring and obstructive sleep apnoea: a questionnaire survey.

A mandibular advancement splint (MAS) may be an alternative treatment for snoring and obstructive sleep apnoea (OSA). However, there is little subjective or objective information concerning long-term effectiveness, compliance and side effects. A retrospective questionnaire was used to survey these issues plus patient satisfaction and maintenance requirements in 166 patients who could have worn a mandibular advancement splint for over a year. One-hundred and twenty-six (76%) subjects returned the questionnaire, (84 with OSA, 42 snorers), of whom 69 (55%) reported still using the splint regularly, 47 (37%) every night. The most common reported reasons for stopping use were discomfort (29/ 57; 52%) of nonusers), and poor perceived efficacy (12 subjects). Users reported more daytime symptoms, and they and their partners were more likely to observe improvements with splint use. Side effects were reported by 49 subjects, more commonly in nonusers. Sixty-five of 67 current users and 23 of 41 nonusers reported less snoring with splint use (p = < 0.001). Long-term mandibular advancement splint usage appeared less satisfactory than previously reported, however, splints were considered effective by 97% of current users and even by over half of those who had stopped use. Reasons for stopping use included side effects, social circumstances, dental treatment, as well as lack of perceived efficacy.

Current principles in the management of obstructive sleep apnoea with mandibular advancement appliances.

This paper looks at the role of mandibular advancement splints in the management of obstructive sleep apnoea, as part of a multidisciplinary approach. Clinical guidance is provided on the rationale for use, patient selection, design features and the associated risk to benefit ratio.

The effects of orthognathic surgery on pharyngeal airway dimensions and quality of sleep.

Orthognathic surgery has been associated with airway narrowing and induction of sleep-related breathing disorders. Therefore, the pharyngeal airway dimensions of 32 orthognathic surgery cases were prospectively investigated, and the relationship between the surgery and sleep quality assessed. Digitized lateral cephalometric radiographs were used to compare oropharyngeal airway morphologies before and after surgery. Patients were assessed in two main surgical groups based on sagittal jaw relationship. A questionnaire was used to assess changes in daytime sleepiness. The mandibular surgery cases were also assessed by overnight domiciliary sleep monitoring. A significant decrease in the retrolingual airway dimension was found in all patients after mandibular setback surgery and a significant increase in this dimension after mandibular advancement. The questionnaire and sleep study revealed no significant changes in snoring incidence or apnoeic events after mandibular setback surgery. For the mandibular advancement group, a change in sleep quality was found, but only in cases with signs of a pre-existing sleep disorder.

A cephalometric comparison of subjects with snoring and obstructive sleep apnoea.

This prospective study analysed the upright lateral cephalometric radiographs of 115 dentate, Caucasian males. Forty-five subjects exhibited proven obstructive sleep apnoea (OSA), 46 were simple snorers, and the remaining 24 subjects, who had no history of respiratory disease and did not snore, acted as controls. Radiographs were traced and digitized, and comparisons were made of the dento-skeletal, soft tissue, and oropharyngeal features of the three groups. Differences were also sought between the snoring and OSA subjects. Of the hard tissue measurements, only the cranial base angle and mandibular body length showed significant inter-group differences (P < 0.001 and P < 0.05, respectively). When the airway and associated structures were examined, both snorers and OSA subjects exhibited narrower airways, reduced oropharyngeal areas, shorter and thicker soft palates, and larger tongues than their control counterparts. Comparison of the two sleep disordered breathing groups showed no differences in any of the skeletal or dental variables examined. However in OSA subjects, the soft palate was larger and thicker (P < 0.05), both lingual and oropharyngeal areas were increased (P < 0.01 and P < 0.05, respectively) and the hyoid was further from the mandibular plane (P < 0.05). Thus, whilst the dento-skeletal patterns of snorers resembled those of subjects with OSA, some differences in soft tissue and hyoid orientation were apparent. There was not, however, a recognizable gradation in size of the airway and its associated structures from control through snoring to OSA subjects. This suggests that there may be a cephalometrically recognizable predisposition towards the development of sleep disordered breathing, but that this is only one facet of the condition.

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.

An investigation into the changes in airway dimension and the efficacy of mandibular advancement appliances in subjects with obstructive sleep apnoea.

This prospective clinical study evaluates a group of 37 male Caucasians with obstructive sleep apnoea for changes in airway dimension and the efficacy associated with the use of mandibular advancement splints. Lateral skull radiographs were obtained with the subjects--upright in occlusion, supine in occlusion, and supine in protrusion. Each radiograph was traced and digitized, and changes in mandibular position, airway dimensions, and hyoid were examined. Subjects were invited to complete pre- and post-treatment questionnaires, and interviewed following fitting of a removable Herbst mandibular advancement splint. Significant changes were recorded in the airway dimensions in response to both a change in position, from upright to supine, and in response to mandibular advancement. A compliance rate of 76 per cent was achieved with no reported serious complications associated with the use of mandibular advancement devices.

Changes in airway and hyoid position in response to mandibular protrusion in subjects with obstructive sleep apnoea (OSA).

This prospective clinical study examined the alterations in airway and hyoid position in response to mandibular advancement in subjects with mild and moderate obstructive sleep apnoea (OSA). Pairs of supine lateral skull radiographs were obtained for 13 female and 45 male, dentate Caucasians. In the first film, the teeth were in maximal intercuspation, while in the second the mandible was postured forwards into a position of maximum comfortable protrusion. Radiographs were traced and digitized, and the alterations in the pharyngeal airway and position of the hyoid were examined. Males and females were analysed separately. In males only, correlations were sought between the changes in hyoid and airway parameters, and the initial and differential radiographic measurements. In males, mean mandibular protrusion at the tip of the lower incisor was 5.3 mm, increasing its distance from the posterior pharyngeal wall by 6.9 mm (or 9 per cent). Movement of the hyoid showed extreme inter-subject variability, both in the amount and direction. In relation to the protruded lower jaw, the hyoid became closer to the gonion by 6.9 mm and to the mandibular plane by 4.3 mm. With respect to the upper face, a 1.3-mm upward and 1.1-mm forward repositioning was seen. The percentage alterations in airway dimensions matched or bettered the mandibular advancement. The minimum distances behind the soft palate and tongue improved by 1.0 and 0.8 mm, respectively. Despite their smaller faces, females frequently showed greater responses to mandibular protrusion than males. No cephalometric features could be identified which might indicate a favourable response of the airway to mandibular protrusion. Larger increments of hyoid movement were associated with an improved airway response, but the strength of the correlations was generally low.

The role of lateral cephalometric radiography and fluoroscopy in assessing mandibular advancement in sleep-related disorders.

Mandibular advancement splints are successful in managing obstructive sleep apnoea (OSA) in selected subjects. For these to be effective, some improvement in the dimensions of the oropharyngeal airway must occur. Twenty subjects with proven obstructive sleep apnoea were examined using lateral cephalometric radiography and a fluoroscopic technique. Cephalograms were analysed, and assessed for both skeletal and soft tissue abnormalities known to be present in OSA subjects. On the basis of these, a prediction was made as to whether the subject's oropharyngeal airway would increase during mandibular protrusion. From the fluoroscopic sequences, the narrowest antero-posterior dimensions of the post-palatal and post-lingual airways were recorded as the mandible moved from the intercuspal position into maximal protrusion. The changes in airway size were noted and these were compared with the predictions made from the static films. In nine subjects, fluoroscopy indicated that the airway opened well during mandibular protrusion, seven did not improve and in four the changes were minimal. Post-palatally the mean airway increase was 2.6 mm, whilst behind the tongue a mean improvement of 3.1 mm was seen. In all but two instances, the cephalometric prediction agreed exactly with the outcome demonstrated by fluoroscopy. All subjects whose airways clearly increased were correctly identified by the cephalogram alone. Cephalometric features associated with a good airway response to protrusion were a reduced lower facial height, low maxillomandibular planes angle and a high hyoid position, accompanied by a normal anteroposterior relationship of the jaws, relatively normal mandibular body length and soft palate area. The more abnormal the skeletal and soft tissue dimensions, the poorer the prognosis. Thus, whilst a single radiograph could indicate whether a positive mandibular response to protrusion could be expected, where doubt existed, a fluoroscopic analysis could provide a useful adjunct to diagnosis.

Treatment changes in Class I and mild Class II malocclusions using the en masse removable appliance.

The aim of this retrospective study was to examine the dental changes which occurred during buccal segment retraction in 39 subjects considered suitable for treatment with headgear to the maxillary dentition. Initially, a removable en masse appliance was fitted to distalize the buccal segments. Once the molar relationship was corrected, fixed appliances were placed for upper arch consolidation and/or alignment. Only five subjects required lower appliance therapy. Twenty-nine individuals had upper second molars extracted as an adjunct to treatment: in the remaining 10 patients these teeth were left in situ. Corresponding lower second molars were extracted in 19 children, whilst 20 pairs of teeth were not removed. Measurements were made at the start of treatment, the completion of buccal segment retraction, and when active treatment was complete. After the first stage, molars and premolars had been retracted nearly 4 mm, whilst the canines showed 2 mm spontaneous distal drift. The inter-molar width had increased by 4 mm and arch perimeter by 5 mm. There was a 5 per cent reduction in crowding. Spontaneous changes were also seen in the lower arch, despite the absence of any therapy. Crowding was slightly improved and inter-molar width increased, apparently as a response to the expansion in the opposing jaw. At the end of treatment, upper arch retraction and expansion were reduced as the teeth were integrated with the lower dentition: the canines required less than 1 mm further retraction. In the lower arch, the expansion of the molars was essentially stable. The extraction of upper second molars did not appear to influence the outcome of treatment. Although slightly more movement appeared to occur in the extraction group, few measurements showed statistical significance.

Spontaneous lower arch changes with and without second molar extractions.

This study describes the spontaneous changes that occurred in the lower arches of 41 children in whom orthodontic treatment was restricted to the upper arch only. In one group, lower second molars were extracted (n = 18), whereas in the other, these teeth remained in situ (n = 23). A two-phase treatment involved distal movement of the buccal segments with an "en masse" appliance and extraoral traction, followed by edgewise mechanics to retract or align the anterior teeth. Only study casts were examined. The occlusal aspects of the lower casts were recorded with the reflex microscope. Models were examined at the start of treatment, at the completion of buccal segment retraction, and when active appliance therapy was complete. The following arch measurements were recorded: intercanine and intermolar width, arch length and perimeter, and the degree of crowding in both the labial segment and the arch as a whole. In the extraction sample, upper buccal segment retraction was associated with increases in all lower arch dimensions and a reduction of crowding. In the nonextraction group, the response was inconsistent. Although arch length and perimeter reduced, intercanine and intermolar dimensions enlarged with minimal alteration in the labial segment crowding. During the second stage of therapy, dimensions generally decreased: arch length, perimeter, and the intercanine width returned to their pretreatment values in the extraction group and were further reduced in the nonextraction sample. However, both arch length and perimeter remained significantly longer in the extraction group. Intermolar width remained stable in both groups, whereas crowding increased. Over the 2-year observation period, arch length, arch perimeter, and crowding exhibited statistically significant differences in behavior between the two groups.

Dental crowding: a comparison of three methods of assessment.

This study was designed to explore a new method for the assessment of dental crowding from study models, which would be both valid and reproducible. This was then tested against two previously reported strategies. A single examiner compared the following methods: visual examination, brass wire/callipers, and a reflex microscope with its customized computer program. Sixty study models (30 maxillary and 30 mandibular) were measured using each technique on two separate occasions. The results showed the reflex microscope method to be the most reproducible, followed by the visual examination and brass wire methods. When testing for validity, as there is no absolutely accurate standard of arch measurement, the individual methods must be compared with one another. From the results, it was seen that the mean values for dental crowding using the reflex microscope, in both the upper and lower arches, were very close to a value which equalled the average obtained from the two means of the visual examination and brass wire methods. The results also indicated that the visual examination and brass wire methods showed a positive bias towards over- and underestimating the degree of crowding, respectively.

The cephalometric morphology of patients with obstructive sleep apnoea (OSA).

This prospective study analysed the lateral cephalometric radiographs of 59 dentate, white, Caucasian males. Thirty-five patients with proven obstructive sleep apnoea (OSA) formed the experimental group, while 24 subjects with no history of respiratory disease acted as controls. Radiographs were traced and digitized, and both hard and soft tissue features were compared between the groups. The pooled data were then subjected to discriminate analysis. Although conventional cephalometric measurements did not differ between the two groups, significant reductions were found in the lengths of the mandibular body and cranial base and in cranial base angulation in OSA subjects. The width of the oropharynx was significantly narrower in this group, particularly in the post-palatal region. The area of the soft palate was increased although that of the tongue was not. Intermaxillary space length (the distance between the posterior pharyngeal wall and the tip of the lower incisor) was decreased, and thus the area in which the tongue had to function was smaller in OSA subjects. From the discriminant analysis, two four-variable models were derived, both of which provided 100 per cent discrimination between the OSA and normal subjects. For the first model the entire OSA group was used: for the second, only obese OSA subjects (those a body mass index > 25) were chosen. The combination off a short mandible and intermaxillary space, with an enlarged soft palate but decreased pharyngeal airway has relevance to the effective management of OSA. In selected patients, advancement of the lower jaw by a nocturnal mandibular repositioning splint may be indicated. The orthodontist would seem to be in a unique position to assist in both the identification and treatment of these subjects.

Obstructive sleep apnoea: fact not fiction.

Obstructive sleep apnoea (OSA) is a recognized clinical disorder in which periods of cessation of breathing occur in the presence of inspiratory effort. Because this may have serious cardio-vascular and pulmonary consequences, diagnosis, and adequate treatment are important. Apart from its medical repercussions, OSA adversely affects the quality of life of both the sufferer and his family. This paper aims to give an overview of the complaint, defining and describing the disorder, reporting its signs and symptoms, and discussing its diagnosis and treatment. Particular attention will be given to those areas in which the orthodontist may play an active role.