The impact of pharyngeal fat tissue on the pathogenesis of obstructive sleep apnea

PURPOSE

Obesity is the most important risk factor for obstructive sleep apnea (OSA); however, the exact underlying mechanisms are still not fully understood. The aim of this study was to examine the morphology of upper airways in overweight habitual snorers and in mild OSA patients. Furthermore, the associations between weight loss, parapharyngeal fat pad area and OSA were assessed in a 1-year randomised, controlled follow-up study originally conducted to determine the effects of lifestyle changes with weight reduction as a treatment of OSA.

METHODS

Thirty-six overweight adult patients with mild OSA [apnea-hypopnea index (AHI) 5-15 events/h] and 24 weight-matched habitual snorers (AHI < 5 events/h) were included in the study. All patients underwent nocturnal cardiorespiratory recordings and multislice computed tomography (CT) of parapharyngeal fat pad area, the smallest diameter and area in naso-, oro- and hypopharynx, the smallest diameter and area of the whole pharyngeal airway, the distance from the hyoid bone to the mandibular plane and to cervical tangent as well as the distance between mandibular symphysis and cervical spine. In addition, OSA patients were further randomised to receive either an active 1-year lifestyle intervention with an early weight loss programme or routine lifestyle counselling. After 1 year, the cardiorespiratory recordings and CT scans were repeated.

RESULTS

The pharyngeal fat pad area was significantly larger, and the distance from the hyoid bone to cervical spine was longer in patients with OSA than in habitual snorers (p = 0.002 and p = 0.018, respectively). The multiple regression analysis showed that besides a large pharyngeal fat pad area and a long distance from the cervical spine to hyoid bone, also a short distance from the mandibular symphysis to cervical tangent increased a risk to OSA. During the 1-year follow-up in OSA patients, the pharyngeal fat pad area and AHI decreased significantly in the intervention group (p = 0.003 and p < 0.001, respectively).

CONCLUSIONS

In the early stages of OSA, the pharyngeal fat pad seems to play an important role in the development of disease in overweight patients. Furthermore, weight reduction by lifestyle intervention-based programme reduces both central obesity and pharyngeal fat pads, resulting in an improvement of OSA.

Standards for permanent tooth emergence in Finnish children

Two groups of Finnish children, 1008 from the eastern part of the country and 569 from the western part, aged 5 to 16 years, were examined to determine the timing of permanent tooth emergence and any regional variation therein. The probit analysis was used to calculate the median ages of eruption. Permanent teeth in the first phase of the mixed dentition erupted earlier and premolars erupted later than previously reported for Scandinavian populations. The former finding could reflect the secular trend; the latter is probably related to the dramatically improved dental health in Finnish children. No regional variation in eruption was found. The median ages of eruption of permanent teeth determined in the present study are suggested for use as national standards for permanent tooth emergence in Finland, separately for girls and boys.

Associations among different orofacial dysfunctions in 9-11-year-olds

This study is the second part of a longitudinal investigation on different orofacial dysfunctions in growing individuals. The aim of the present report was to determine, in 219 children with and without articulatory speech disorders, whether certain associations among misarticulations of speech, craniomandibular disorders (CMD), and problems in oral motor skills still were found at the age of 9-11 years, as they had been in these children at the age of 6-8 years. Multiple logistic regression models showed that certain aspects of dental malocclusion such as large overjet, anterior open bite and lateral cross-bite, and certain signs of CMD such as palpatory tenderness of the TMJ, jaw deviation on opening and bruxism were related to misarticulations of speech. Children with sounds produced too far posteriorly seemed to have a smaller maximal opening but larger laterotrusive and protrusive movement capacities of the mandible than children with correct speech articulation. Despite maturation of the oral motor skills with age, among 9-11-year-olds various orofacial dysfunctions still seemed to be associated with each other. This probably indicates fixation of certain speech misarticulations rather than immaturity of the fine motor control.

Changes in function of the masticatory system from 7 to 10 years of age in relation to articulatory speech disorders

The aim of the present study was to determine changes in function of the masticatory system in children with articulatory speech disorders and in the controls by re-examining a sample of 287 previously studied children from 7 to 10 years of age. Articulatory speech disorders were diagnosed by the same speech therapist during spontaneous speech and test words using the Remes Articulation Test. Mandibular movement capacity, occlusal interferences, slide between retruded and intercuspal positions, and signs and symptoms of the craniomandibular disorders (CMD) were recorded by a dentist. The follow-up results showed that mandibular movement capacity increased in almost all individuals, decreasing only in about 10% of cases. However, among children with speech disorders lateral jaw movements decreased in about 30% of subjects. During growth the prevalence of CMD increased while single signs and symptoms fluctuated. Differences between the groups for expression of CMD, mandibular movement capacity and occlusal recordings mainly levelled off. Higher constancy of subjective symptoms and retrusive interferences in children with speech disorders than in the controls supports our previous findings that, in growing individuals, different orofacial dysfunctions seem to be associated with each other.

Eruption pattern of permanent teeth in a rural community in northeastern Finland

Cross-sectional data on permanent tooth eruption were collected by examining the children and adolescents 5-15 years old in a northeastern municipality of Finland. There were 1008 subjects in the whole sample, 483 girls and 525 boys. The results showed statistically significant differences between the girls and boys in timing of eruption of some permanent teeth, indicating earlier eruption in girls than in boys. This difference was most clearly seen in the second phase of the mixed dentition. Interindividual variation in the emergence age was also wider in the second phase of the mixed dentition. The present results seem to indicate earlier eruption of the permanent teeth in rural children in northeastern Finland than in other parts of the country.

Relationship between craniomandibular dysfunction and pattern of speech sound production in a series of first-graders

This report investigates associations between prevalence of functional disturbances of the masticatory system and speech disorders. The subjects were 157 children referred for speech therapy to the hospital and a control group all 130 first-graders at two elementary schools, mean age 7 years 6 months. During clinical examinations, signs and symptoms of TMJ dysfunction were recorded by the same dentist. Articulatory speech disorders were diagnosed by the same phoniatrician using the Remes Articulatory Test (Remes, 1975) for the Finnish language. The results showed that in the hospital referral group the mean value for maximal opening was smaller while laterotrusion movements and maximal protrusion of the mandible were larger than in the control group. The study group also more often had CM disorders and occlusal interferences than children of the first grade sample. In the present data, a higher frequency of subjective symptoms and several clinical signs of CMD were related to certain articulatory speech disorders. Risk of having too anteriorly-produced sounds, mainly 's'-sounds, decreased with advancing age in 6-8-year-old children. In conclusion, expression of both craniomandibular disorder and disorders in speech sound production seem to a considerable extent to reflect immaturity of fine motor control of the orofacial muscles in 6-8-year-old children.

Developmental stage of the dentition and speech sound production in a series of first-grade schoolchildren

This study was undertaken to investigate the effect of developmental stage of the dentition on speech sound production in children with and without articulatory speech disorders. In the whole sample, there were 281 subjects, mean age 7.5 years (SD 0.4). The stage of the eruption of the permanent incisors was calculated as the percentage height of each tooth of the mean crown height of the corresponding tooth in a group of 252 young adults. Eruptional stage of the first permanent molars was classified into three categories. Articulatory disorders were diagnosed by one experienced speech therapist and phoniatrician using the Remes Articulation Test [Remes, 1975] for the Finnish language. The results showed a wide interindividual variation in developmental stage of the dentition in a group of 7-year-old children with a tendency of the first permanent molars but not the incisors to erupt earlier in girls than in boys. Boys had a higher frequency of misarticulations estimated to need treatment than did girls. The present results indicate that during eruption of permanent teeth it is more important to draw attention to symmetrical eruption and to individual timing pattern rather than to the mean values of tooth eruption in subjects of the same age. The findings also suggest a decreasing risk of faulty speech sound production with advancing eruption of some permanent teeth still present in 7-year-old children.

Variation in function of the masticatory system in 1008 rural children

The aim on the present study was to investigate the variation in function of the masticatory system in 1008 subjects 5 to 15-years-old in a rural community. This study considered the effects of age, gender, developmental stage of the dentition and interexaminer variability. In addition, maximal opening capacity of the mandible was assessed in relation to age, gender and body size. Four dentists performed the examinations combined with routine check-ups, preventive and operative dental treatments. The results showed that the opening capacity in children increases from the age of 6 to the age of 12 with no difference between the sexes. Children of bigger size seem to have larger opening than the smaller ones. Minor differences were found between the sexes, but some variation with age could be seen in signs of craniomandibular disorders (CMD) and in occlusal recordings. Children with RP-IP slide had more often CMD-signs than the ones without this occlusal feature mainly from the instability of occlusion. This is in accordance with the finding of a higher prevalence of muscle tenderness and mediotrusion interferences during the mixed dentition. In general, in children expression of the craniomandibular disorders seems to reflect physiological changes during development of the dentition and occlusion rather than a pathological condition.