Nasorespiratory function and head posture

Impaired nasal breathing has been reported to cause changes in human head posture. The aim of this study was to assess whether there was any relationship between nasorespiratory function and variables of head posture in 58 young adults. The pressure flow technique was used to measure airflow rate and oral/nasal pressure and to calculate the smallest cross-sectional area of the nasal airway. A natural head position roentgenocephalogram was used to measure the craniovertical angulation (NSL/VER), craniocervical angulation (NSL/OPT), and cervical spine inclination (OPT/HOR). The results showed a trend toward enlarged craniocervical angulation and forward inclination of the cervical spine in subjects with a relatively large nasal cross-sectional area. Though the general opinion on the effects of reduced upper airway size on head posture is opposite, these results are an experimental confirmation of the theoretically expected mechanism that leads to increased head extension in obstructed subjects.

Emergence of permanent teeth in Tanzanian children

OBJECTIVE

The aim of the present study was to investigate the emergence of permanent teeth among Tanzanian children.

METHODS

A total of 869 Tanzanian children were recruited from 16 schools in age groups 3.5-5, 6.5-8, 9.5-11 and 15-16 years of whom 428 (49%) were boys and 441 (51%) were girls. The effects of age and gender on the emergence stages of the dentition were determined for the four age groups.

RESULTS

Girls, but not boys, had some permanent maxillary canines, second premolars and mandibular and maxillary second molars as early as at the age of 6.5-8 years. Permanent teeth of both the first and the second transitional periods were already emerging at the age of 3.5-5 years and 6.5-8 years, respectively. At 3.5-5 years, 9% of the permanent teeth belonging to the first transitional period were already in occlusion. Emergence of incisors and first molars was more advanced in girls than in boys in age groups 3.5-5 and 6.5-8 years.

CONCLUSIONS

Parallel to earlier reports on different ethnic groups, the results of this study indicate that the permanent teeth of Tanzanian children erupt earlier in girls than in boys, and the mandibular teeth erupt earlier than the corresponding maxillary teeth. The difference between boys and girls was found in both the first and second transitional period. Permanent teeth in Tanzanian children clearly emerge earlier than in Caucasian children.

Effects of age, body mass index, and gender on nasal airflow rate and pressures

OBJECTIVES

The purpose of this study was to evaluate the variation of airflow rate and oral-nasal pressure with age, body mass index (BMI), and gender (i.e., to evaluate whether the effects of age, BMI, and gender on airflow rate and pressures are convergent with their effects on nasal cross-sectional area and resistance).

STUDY DESIGN

A cross-sectional study of 332 subjects (214 female and 118 male subjects) aged 16 to 82 years.

METHODS

The aerodynamic measurements of nasal airflow rate and nasal and oral pressures were performed by posterior rhinomanometry. Age, gender, weight, and height were recorded for each subject, and the BMI was calculated. The effects of age, BMI, and gender on airflow rate and nasal and oral pressures were estimated by ANOVA.

RESULTS

Nasal airflow rate and oral and nasal pressures increased with increasing BMI. In addition, the mean values of airflow rate and pressures were significantly higher in male than in female subjects. Increasing age was related to increased oral pressure, but was not associated with airflow rate or nasal pressure.

CONCLUSIONS

This study suggests that, on the contrary to the findings in children and adolescents, BMI and gender should be taken into consideration when measuring the patency of upper airway in adults.

Do early signs of orofacial dysfunctions and occlusal variables predict development of TMD in adolescence?

The aim of the present report was to focus on if early signs of different orofacial dysfunctions, e.g. misarticulations of speech, problems in oral motor skills and TMD, malocclusions or occlusal interferences could predict the development of temporomandibular disorders (TMD) in adolescence. Altogether there were 94 children referred for speech therapy and 93 controls who participated in all three stages of this longitudinal study. In the whole sample the mean age during the first examination was 7.6 years, during the second examination 10.6 years, and during the third one 15.4 years. Multiple logistic regression models showed that subjects with a tendency to open bite tended to have palpatory tenderness of the muscles. Overjet was positively related to hypermobile but negatively to hypomobile jaw movements. Deviation on opening was associated with problems in oral motor skills, and some signs of TMD seemed to be related to each other. In addition, girls had a higher risk of having several signs of TMD than boys did. In conclusion, tendency to open bite, both mesial and distal molar occlusion and increased and decreased overjet were occlusal anomalies associated with TMD. Altogether, among 15-year-olds there seems to be both local and central factors in the aetiology of TMD.

Variation of nasal respiratory pattern with age during growth and development

The purpose of this study was to determine changes in nasal respiratory pattern with growth and development, particularly to determine the age where upper airway growth ceases. The results on 361 healthy subjects, aged 7 to 24 years, based on aerodynamic measurements during rest breathing, showed clear differences between inspiratory and expiratory phases. Nasal airflow rate and cross-sectional area increased and oral-nasal pressure and nasal resistance decreased with age up to the age of 16, levelling by the age of 20 years. The body size and gender had effect only on nasal airflow rate. This study suggests that the measurements of the nasal respiratory pattern, determining impaired nasal airway, should be done during inspiration and using age-related assesment from a healthy population until the age of 16 years. From then on, guidelines for adults are applicable.

Hyoid bone position after surgical mandibular advancement

A cephalometric evaluation of the changes in the horizontal and vertical placement of the hyoid bone and of those in the position of the head over the cervical spine after surgical mandibular advancement was undertaken. Seven linear and one angular measurement were investigated in 60 patients, 17 males and 43 females, before and one year after surgical mandibular advancement. The hyoid bone moved forwards horizontally in 78 per cent of the subjects, backwards in 17 per cent, and in 5 per cent of patients it retained its pre-operative position. It moved vertically downwards in 32 per cent of subjects, and in 63 per cent it moved upwards and closer to the body of mandible. The amount of horizontal and vertical change of the hyoid bone was associated with the corresponding change of the mandible after surgery. The vertical change was more distinct in females compared with males. There was variation in the position of the head over the cervical spine; it showed extension in 26.7 per cent of the sample, flexion in 71.7 per cent, and remained the same in only 1.6 per cent after surgery. The results show that with surgical mandibular advancement the hyoid bone follows mainly the advancement of the mandible and moves closer to the body of the mandible. However, there are variations in the changes of hyoid bone and head position that are difficult to predict.

Palatal morphology and type of clefting

In this study, the variation in palatal dimensions, particularly for height, width, and depth, were evaluated in subjects with different types of cleft palate using the moiré technique. The sample consisted of 95 subjects with cleft palate and 68 noncleft individuals. Effects of cleft type, gender, developmental stage of the dentition, missing teeth, and 11 skeletal and pharyngeal cephalometric variables on palatal dimensions were assessed using multiple-regression analyses. The typing of clefts had an effect on the all palatal dimensions. The palate was shallower in subjects with clefts involving the secondary palate than in other types of clefts or in noncleft individuals. The palatal width was decreased in subjects with cleft in the primary palate, and the palatal depth was affected by all cleft types except submucous cleft. Gender, developmental stage of the dentition, missing teeth, and some of the cephalometric variables also had a certain effect on the palatal dimensions.

Changes in TMD signs and in mandibular movements from 10 to 15 years of age in relation to articulatory speech disorders

This study is part of a longitudinal study on the associations between different orofacial dysfunctions. The aim was to determine changes in signs of temporomandibular disorders (TMD) and in mandibular movement capacity in subjects with articulatory speech disorders and in controls by re-examining a sample of 187 previously studied children from 10 to 15 years of age. Articulatory speech disorders were diagnosed by a phoniatrician. Mandibular movement capacity, signs of TMD, occlusal contacts/ interference and slide between retruded and intercuspal positions were recorded by a dentist. The follow-up results showed that mandibular mobility mainly increased up to the age of 15, but there was a decrease in protrusion capacity in almost half of the cases. This fluctuation probably reflects the normal changes in growth pattern. Signs of TMDs proved to be inconsistent in nature, especially among the controls. With age, girls in the control group, more so than boys, were prone to new signs of TMD, but no gender difference was found in the group of subjects with misarticulations of speech. The findings indicate that in adolescence different orofacial dysfunctions are related.

Nasal impairment in prepubertal children

The aim of this study was to examine changes in nasal resistance longitudinally from age 9 to 13. The study population consisted of 82 children whose nasal resistance was measured annually. The results showed that as nasal resistance significantly decreased with age, it also increased transiently at some point between ages 9 and 13. The timing of the transient change in resistance varied among individuals, but it usually occurred before age 12. No gender differences were observed. The results suggest that clinical signs of nasal impairment may periodically occur and then disappear in prepubertal orthodontic patients.

Secular trends affect timing of emergence of permanent teeth

OBJECTIVE

To examine the expression of possible secular trend in timing of the emergence of permanent teeth in Finnish children over the past few decades, considering the differences between genders.

MATERIALS AND METHODS

Two age groups of Finnish children, one born in 1976-1985 (group 1980) and the other born in 1999-2002 (group 2000), were examined. Group 2000 comprised 483 children (235 girls and 248 boys) aged 6.4 to 8.5 years at the time of the examination, and the same children were examined at the age of 9.0 to 11.8 years. Altogether 405 children could be recalled, 196 girls and 209 boys. For comparison, matching age groups were selected from the group 1980 data (n = 1579), resulting in a sample of 312 children (155 girls and 157 boys) aged 6.4 to 8.5 years and 393 children aged 9.0 to 11.8 years. The emergence stage of each permanent tooth was determined clinically (Grades 0-3), based on which the subjects were furthermore divided according to the emergence stage of the dentition.

RESULTS

Linear regression models showed that the permanent teeth of the first phase of the mixed dentition erupted earlier in group 2000 than in group 1980, but the teeth of the second phase of the mixed dentition erupted later in group 2000. Girls showed more advanced tooth eruption than boys.

CONCLUSION

The longer duration of mixed dentition in group 2000 than in group 1980 makes the duration of combined follow-up and active treatment longer, and should be considered in timing of efficient orthodontic treatment.

Palatal asymmetry in cleft palate subjects

In subjects with different types of cleft palate, palatal shape and symmetry were evaluated utilizing the moiré contourography technique. The sample consisted of 95 subjects with cleft palate and 68 controls. The differences between cleft and control subjects in the transverse and anteroposterior location of the highest point of the palate, palatal axis angle, and the palatal index were assessed by analysis of variance. Effects of cleft type, gender, developmental stage of the dentition, missing teeth, and eight skeletal and pharyngeal cephalometric variables on palatal shape and symmetry were assessed using multiple-regression analyses. In comparison with the noncleft individuals, the cleft palate subjects showed parallel but clearly more remarkable asymmetry in palatal shape and position of the first maxillary molars. The anteroposterior location of the deepest point in the palate was more posterior, and the palate was relatively shallower. The severity of the cleft type affected both the anteroposterior and transverse position of the highest point in palatal morphology.

Occlusal characteristics during different emergence stages of the permanent dentition in Tanzanian Bantu and Finnish children

Occlusal characteristics and anomalies were studied among 869 (428 boys, 441 girls) Tanzanian Bantu children aged 3.5-16 years and 706 (319 boys, 387 girls) Finnish children aged 5-11 years during different emergence stages of the permanent dentition. Various occlusal variables were registered according to described criteria. Multiple linear regression, ANOVA, t-test, Chi-square and logistic regression models were used to test for various statistically significant differences between different subgroups. Significant differences between Tanzanians and Finns were found for malocclusion, neutral and distal molar occlusion, mean values for overjet and overbite, overjet greater than 5 mm, deep bite and anterior open bite (all P < 0.0001). The most prevalent anomalies among Tanzanians were anterior open bite (7-19 per cent), increased overjet (3-19 per cent) and distal molar occlusion (3-16 per cent). For the Finns, distal molar occlusion (18-38 per cent) was the most prevalent anomaly, followed by deep bite (4-22 per cent) and increased overjet (4-40 per cent). An anterior crossbite was rare and equally distributed among the two ethnic groups. Girls had a larger mean value for overbite (P = 0.003) and more often a deep bite (P < 0.01) than boys. Mandibular incisor crowding among children with neutral occlusion (Class I malocclusion) occurred significantly more often among Finnish than Tanzanian children. In conclusion, various developmental changes in occlusion were observed leading to variation in occlusal characteristics and anomalies according to the emergence stages of the permanent dentition. Most of the classic malocclusions occur among Tanzanian children, but the prevalence differs from that in other parts of the world.

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.

Upper airway resistance during growth: A longitudinal study of children from 8 to 17 years of age

OBJECTIVE

To study upper airway breathing in 115 children annually from 8 to 17 years of age with the hypothesis that upper airway respiratory needs increase steadily during growth and show sexual dimorphism.

MATERIAL AND METHODS

To calculate nasal resistance, airflow rate (mL/s) and oronasal pressures (cmH2O) were measured during rest breathing in a seated position using the pressure-flow technique.

RESULTS

Median values of oronasal pressure ranged at different ages in girls from 0.88 to 1.13 and in boys from 0.92 to 1.44 cmH2O, being 0.95 and 0.93 cmH2O at the age of 17 years, respectively. The gender differences were statistically significant in four age groups (P < .05 by the Mann-Whitney test). Mean values of nasal resistance decreased from 8 to 17 years of age in girls from 4.0 (±3.27) to 2.4 (±2.30) and in boys from 3.3 (±2.48) to 1.5 (±0.81) cmH2O/L/s. However, there was an increase in resistance in 11-year-old girls and 12-year-old boys and at the age of 15 in both genders (P < .05 by paired t-test).

CONCLUSIONS

Respiratory efforts stabilize oronasal pressure to maintain vital functions at optimal level. Nasal resistance decreased with age but increased temporarily at the prepubertal and pubertal phases, in accordance with other growth and possibly hormonal changes. When measuring upper airway function for clinical purposes, especially in patients with sleep apnea, asthma, allergies, cleft palate, or maxillary expansion, the measurements need to be compared with age- and gender-specific values obtained from healthy children.

Guideline Values for Minimum Nasal Cross-Sectional Area in Children

OBJECTIVE

The purpose was to determine age-specific values of the minimum cross-sectional area of the nasal airway in children without cleft lip or palate and to assess whether gender differences occur with growth in order to develop guidelines for assessment in children with clefts.

PARTICIPANTS

All schoolchildren aged 8 to 17 years who met the research criteria were studied during rest breathing using the pressure-flow technique. The children came from a rural area of 3800 inhabitants. Consecutive age cohorts were used for comparisons.

RESULTS

Nasal cross-sectional area increased in females from 0.38 cm² in 8-year-olds to 0.58 cm² in 17-year-olds. There was a decrease in size at ages 10 to 11 and 14 to 15 years. In males, the area increased from 0.40 to 0.68 cm² and decreased slightly from 9 to 10 and 14 to 15 years. The annual changes were statistically significant in females between 8 and 9 and 11 to 13 years of age, and in males from 11 to 12, 13 to 14, and 15 to 17 years of age. Across gender, the only significant difference occurred at age 16.

CONCLUSIONS

Our results indicate that the increase in nasal airway size is not consistent during growth. Nasal airway size showed almost equal values for both genders in young children but was systematically larger in boys from 14 years of age on. The results refer that by 17 years of age nasal airway may not have reached adult size in males.

Should a history of nasal symptoms be considered when estimating nasal patency?

The purpose of this study was to determine if a history of certain nasal symptoms and ear, nose, throat, or lung disease should be taken into consideration when measuring patency of the nasal airway. The pressure-flow technique was used to measure nasal cross-sectional area and resistance in 249 healthy and nasally asymptomatic 16- to 82-year-old individuals. The subjects were also asked to complete a questionnaire of possible airway problems. The results showed that there were statistically significant differences in minimum nasal cross-sectional area and upper airway resistance between males and females, between individuals with and without allergic rhinitis, and between smokers and nonsmokers. However, these differences were too small to be of physiological or clinical importance. Therefore, when determining nasal cross-sectional area and resistance in individuals with a history of upper or lower airway problems, measurements can be assumed to be accurate, irrespective of other factors, as long as they are made during an asymptomatic period.

A longitudinal study of nasal airway size from age 9 to age 13

In order to define nasal breathing for diagnostic purposes, reference values of normal nasal airway size in children are needed. The purpose of this study was to examine longitudinally changes in nasal airway size that occur with age. Minimum nasal cross-sectional areas of 82 children were measured by the pressure-flow technique at 1-year intervals, from age 9 through age 13. A mixed factorial ANOVA showed that the effect of age on nasal airway size was statistically significant (p<0.001) and the effect of gender was nonsignificant. Although the mean nasal size increased from 0.4 cm2 to 0.5 cm2, it also decreased at some point between 9 and 13 years. The results suggest that the adult nasal size may be reached earlier than previously reported in cross-sectional studies.

Perception and Respiratory Responses of the Upper Airway Mechanism to Added Resistance With Aging

Objectives

To assess breathing behaviors and perception of added respiratory loads in young compared to old individuals, and to determine whether aging affects the perception and response to changes in nasal airway resistance.

Study design

In a clinical study, 40 young (11-20 years) and 40 older (59-82 years) subjects were evaluated during rest breathing and during the application of added airway resistance loads.

Methods

The pressure-flow technique was used to measure airflow rate (mL/s) and oral-nasal pressures (cmH₂O) to calculate nasal resistance (cmH₂O/L/s). To create calibrated resistance loads for the test conditions, we used a device modified from a precision iris diaphragm.

Results

During rest breathing airflow rate was significantly lower for the younger group compared to older group. Using the loading device, 11-20-year-olds detected increased resistance at the level of 2.26 cmH₂O/L/s compared to 4.55 cmH₂O/L/s in 59-82-year-olds. In contrast to the younger group, mean airflow rate was higher during expiration than during inspiration among 59-82-year-olds except at rest breathing.

Conclusions

The data revealed that the perception and respiratory response to increased airway resistance changed with aging. Younger subjects were more sensitive to changes within the airway. In both groups, subjects responded to increased airway resistance by decreasing airflow rate. However, expiratory phase became more active than inspiratory phase only in the older group.

Level of Evidence

N/A.