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Biomedical subjects

Ama Johal

Publications and source records attributed to Ama Johal.

6 recordsLinked to original sources
PubMed2007

The effect of mandibular advancement appliances on awake upper airway and masticatory muscle activity in patients with obstructive sleep apnoea.

BACKGROUND: There is little understanding of how dental appliances, designed to posture the mandible forwards, act on pharyngeal airway dilatory and masticatory muscles in patients with obstructive sleep apnoea (OSA). This study evaluates, in a prospective cohort design, the effect of mandibular advancement splints (MAS) on awake genioglossus (GG), geniohyoid (GH) and masseter (M) muscle activity. METHODS: Fifty OSA patients received a custom-made removable Herbst MAS appliance, adjusted for maximum therapeutic benefit, as judged by subjective improvement. Awake electromyographic (EMG) activity was recorded at baseline and with the MAS in situ, by using bipolar surface electrodes in patients seated upright and in the natural head position. The lower splint was modified to facilitate the placement of the intra-oral bipolar surface electrodes used to record GG EMG activity. RESULTS: Significant increases in GG (P = 0.041), GH (P<0.001) and M (P<0.001) muscle activity accompanied placement of the MAS. CONCLUSIONS: These findings support the contention of a physiological role, which may act to augment the anatomical action of MAS.

Cohort Studies↗
PubMed2006

Health-related quality of life in patients with sleep-disordered breathing: effect of mandibular advancement appliances.

STATEMENT OF PROBLEM: Mandibular advancement appliances (MAAs) are increasingly being recognized in the management of sleep-disordered breathing (SDB). However, there is little available evidence regarding their impact on health-related quality of life. PURPOSE: A prospective, nonrandomized controlled clinical trial was undertaken to evaluate the effect of MAA treatment on the quality of life of patients with SDB. MATERIAL AND METHODS: Two hundred fifteen consecutively referred patients for MAA therapy who had a diagnosis of SDB confirmed by overnight polysomnography were recruited for study. The test group (n=120) received a Herbst appliance, a removable appliance comprised of separate maxillary and mandibular complete occlusal coverage acrylic splints, connected by means of bilateral telescopic arms. Patients in the control group (n=95) remained untreated for 4 months. All patients completed the Medical Outcomes Study 36-Item Short-Form Health Survey at baseline (T1) and at follow-up (T2). Cross-tabulation was performed for each independent variable against the group (control versus test) to determine the number of subjects and the percentage showing improvement and the level of significance (alpha=.05). Data were dichotomized (improvement versus no improvement), analyzed by simple logistic regression analysis, and expressed as the odds ratio. RESULTS: Eighty-three (87%) control and 107 (89%) test patients completed the study. No statistical differences were observed at baseline in any of the parameters relating to severity of SDB, demographic, anthropometric, or quality of life measures between the 2 groups. Significant differences were observed in relation to the energy/vitality (P=.001) and physical role limitation (P=.025) domains following 4 months of treatment with an MAA. CONCLUSIONS: Mandibular advancement appliances have a significant effect on a limited number of health-related quality of life domains for patients with SDB.

Activities of Daily Living↗
PubMed2005

Sleep nasendoscopy: a diagnostic tool for predicting treatment success with mandibular advancement splints in obstructive sleep apnoea.

This prospective, cohort study evaluated the role of sleep nasendoscopy (SNE) with simultaneous mandibular protrusion in predicting successful mandibular advancement splint (MAS) therapy in subjects with obstructive sleep apnoea (OSA). Nineteen OSA subjects diagnosed by overnight polysomnography were referred for MAS therapy, following SNE investigation. A Herbst MAS was fabricated for each subject. Once this had been adjusted for maximal, subjective, therapeutic effect, follow-up sleep studies were undertaken with the appliance in situ. The SNE was repeated with the appliance in place to allow the effects of the original mandibular protrusion and the actual effect of the MAS to be compared. The MAS was removed and the original and current site(s) of obstruction evaluated. Pre-treatment SNE showed airway obstruction at the following levels: intermittent multi-level (16 subjects), sustained multi-level (two subjects) and tongue base (one subject). In all individuals, gentle advancement of the mandible during SNE improved airway patency and reduced snoring. When the SNE was repeated with the MAS in situ, all subjects showed improvements in snoring and airway patency. Follow-up sleep studies confirmed the efficacy of the MAS, with all patients showing a reduction in the apnoea/hypopnoea index (AHI). Median reductions in AHI (from 28.1 to 6.1, P < 0.001) and Epworth Sleepiness Scale (ESS) scores (from 9 to 6, P < 0.001) were highly statistically significant. The results suggest that SNE with concomitant mandibular advancement to mimic MAS wear, could be a valuable prognostic indicator of successful MAS treatment.

Adult↗
PubMed2004

Maxillary morphology in obstructive sleep apnea: a cephalometric and model study.

The relationship between maxillary constriction and the etiology of obstructive sleep apnea (OSA) is not clear. This prospective case-control study compared maxillary morphology in 94 dentate subjects (47 OSA and 47 control subjects), using upright lateral cephalograms and study models. Each subject had height, weight, and neck circumference measurements recorded and underwent an orthodontic examination. An upright lateral cephalogram and dental impressions were obtained. All data were analyzed using the SPSS statistical package applying nonparametric tests at the 5% level of significance. Male and female subjects were examined separately, and statistically significant differences were found between the cephalometric measurements for OSA and the control subjects. The palatal angle was more obtuse in male OSA subjects (P < .05). The PNS-posterior pharyngeal wall was shorter (P < .05) and the soft palate longer in female OSA subjects (P < .05). Minimum palatal airway widths were significantly reduced in both male (P < .01) and female (P < .001) subjects. In the comparison of study model measurements, palatal heights in OSA subjects were greater (P < .05). Thus, maxillary morphological differences do exist between OSA and control subjects, supporting their role as a etiological factor.

Adult↗
PubMed2002

Postural variation in oropharyngeal dimensions in subjects with sleep disordered breathing: a cephalometric study.

This radiographic study analysed the changes that occurred in the airway and surrounding structures when subjects with sleep disordered breathing moved from the upright to the supine position. Radiographs of 100 dentate, Caucasian males were examined. Fifty individuals were non-apnoeic snorers and in 50 a diagnosis of obstructive sleep apnoea (OSA) had been confirmed by polysomnography. Radiographs were traced and digitized and comparisons were made of the behaviour of the oropharynx, soft palate, tongue, and hyoid between the two groups. When moving from the upright to the supine position, both OSA and snoring subjects showed a similar pattern of change. The antero-posterior dimensions of the oropharyngeal airway decreased highly significantly (P < 0.001) at all levels, with a concomitant reduction in cross-sectional area (P < 0.001). The narrowing was most severe behind the soft palate, where the minimum airway reduced by approximately 40 per cent. Behind the tongue, a 20 per cent decrease was seen. The soft palate showed small but significant increases in area, whilst the tongue altered in shape but not in its overall cross-sectional area. In non-apnoeic snorers only, tongue proportion increased (P < 0.05). At the same time, the hyoid dropped and moved anteriorly, maintaining a constant relationship with the lower border of the mandible. There were no differences between the non-apnoeic snorers and the OSA subjects in any of the postural changes recorded.

Anatomy, Cross-Sectional↗