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.

Changes in head and cervical-spine postures and EMG activities of masticatory muscles following treatment with complete upper and partial lower denture.

A clinical stomatognathic, cephalometric and electromyographic (EMG) study was performed in relation to 14 subjects (10 women, 4 men), each with an edentulous maxilla and residual mandibular dentition before and six months after treatment with complete upper and partial lower dentures. The mean age of the subjects was 54.4 years (range 43-64 years). The mean period of edentulousness and age of dentures were 22.5 years (range 15-33 years) and 14.1 (range 1.5-30 years), respectively. Natural head position was recorded (using a fluid-level method) and measured from cephalograms. EMG activity was measured in relation to masseter and temporal muscles. A decrease in clinical dysfunction index was noted in 12 of 14 subjects (86%). There was no change in cervical inclination, but a slight extension of the head was noted after treatment. Rapid recovery of the masticatory muscles was reflected in increased EMG activity, especially when biting in the maximal intercuspal position. In cases of edentulous maxilla and residual mandibular anterior dentition, treatment with a complete upper and lower partial denture had a favorable effect on craniomandibular disorders and masticatory-muscle function.

Head posture and cervicovertebral anatomy as mandibular growth predictors.

In this study, the separate and the combined influence of head posture and cervicovertebral anatomy on mandibular growth direction was analysed. The subjects, 20 boys and 16 girls, were a subsample of 12-year-old Chinese children in Hong Kong, all with initial and 2-5-year follow-up lateral cephalometric radiographs recorded in natural head position (NHP). Postural variables were measured in terms of craniovertical, craniocervical, and cervicohorizontal angulations. Morphological variables of the craniocervical junction region were measured in terms of intervertebral space and atlantoaxial dimensions. Mandibular growth was estimated as the direction of displacement of prognathion in relation to the sella nasion line when superimposing on stable cranial base structures. The data were analysed with a multiple regression model, separately for boys and girls. In both sexes the height of the atlas dorsal arch showed a statistically significant correlation (P < 0.01) with mandibular growth direction (boys r = 0.54 and girls r = 0.62), while the craniovertical angulation correlated significantly only for the boys (NSL/VER r = 0.59, P < 0.01; C1/VER r = 0.49, P < 0.05). However, atlas dorsal arch height (DORS C1) combined with cervicohorizontal angulation (OPT/HOR) in girls and with craniovertical angulation (NSL/VER; C1/VER) in boys, displayed a significantly (P < 0.05) increased correlation (r = 0.76 and 0.71, respectively). Combination of atlas morphology and head posture predicts mandibular growth direction better than either variable alone.

A modification of the pressure-flow technique for measuring breathing of cold air and its effect on nasal cross-sectional area.

The purpose of this article was to develop a method based on the pressure-flow technique for measuring cold air breathing and to observe the immediate reactions of breathing function to cold air inhalation in 40 subjectively healthy 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. The equipment was modified to allow measurements both at room temperature and with cooled air by connecting the nasal mask to a freezer with a two-valve cylinder and tubing. Nasal cross-sectional area showed a significant decrease from 42.3 mm2 at room temperature to 37.6 mm2 with cooled air. Correspondingly, the airflow rate changed from 411 ml/s to 369 ml/s, whereas the differential pressure remained about the same, 1.2 and 1.3 cm H2O, respectively. The interindividual variation was fairly large. The results suggest that the breathing of cold air seems to cause changes in nasal cross-sectional area and airflow rate. In general, the cross-sectional area diminishes, the change being quantitatively more pronounced in subjects with an initially large area.

A natural head position technique for radiographic cephalometry.

A three-part study was designed in order to test the applicability of the fluid-level method for registration of natural head position. In the first part the fluid-level method was utilized to make two repeated cephalometric radiographs of 33 young adults. The reproducibility of the craniovertical, craniocervical and cervicohorizontal relationships was comparable with previous results with the mirror method. In the second part, the fluid-level method was compared with the mirror method when used by two radiographers for repeated radiographs in 40 subjects. The reproducibility of the craniocervical and cervicohorizontal angles was less accurate with both methods and the only difference between them was a slightly better reproducibility of the craniovertical angle with the fluid-level method for one of the radiographers. In the third part, it was shown that using the fluid level, a patient can be transferred from a standing to a sitting position in the cephalostat without any systematic change in craniovertical, craniocervical or cervicohorizontal relationships.

Head posture and cervicovertebral and craniofacial morphology in patients with craniomandibular dysfunction.

A relationship between particular characteristics of dental occlusion and craniomandibular disorders (CMD) has been reported, while less attention has been focused on the possible effect of dysfunction of the masticatory system on head posture or cervicovertebral and craniofacial morphology. Natural head position roentgen-cephalograms of 16 young adults with complete dentition taken before and after stomatognathic treatment displayed an extended head posture, smaller size of the uppermost cervical vertebrae, decreased posterior to anterior face height ratio, and a flattened cranial base as compared with age- and sex-matched healthy controls. The lordosis of the cervical spine straightened after stomatognathic treatment. The results are an indication of the close interrelationship between the masticatory muscle system and the muscles supporting the head, and lead to speculation on the principles of treating craniomandibular disorders.

Craniofacial growth in shunt-treated hydrocephalics: a four-year roentgenocephalometric follow-up study.

The craniofacial growth of 24 shunt-treated hydrocephalics aged 5-15 years was evaluated over a 4-year period, by comparing changes in linear and angular cephalometric variables with those of an age- and sex-matched control group. The main findings were increased calvarial thickness, increased cranial base flexure, superior displacement of the sella, and a tendency for the gonial angle to remain more obtuse in the shunt-treated patients. As craniofacial growth in the latter differed only slightly from that observed in the controls, the deviations in facial morphology observed in a previous cross-sectional study of shunt-treated hydrocephalics can be taken to represent a long-term effect of the shunt treatment.

Craniofacial asymmetries in shunt-treated hydrocephalic children.

The degree and direction of craniofacial asymmetry in the frontal plane was studied in a sample of 26 shunt-treated hydrocephalic children aged 5 to 18 years. Thirteen of the children had the regulating shunt fixed on the right side of the head and 13 on the left. The shunt had usually been inserted during the first years of life. An age- and sex-matched group of healthy school children and students served as controls for cephalometric assessment by means of linear and angular measurements. Considerable craniofacial asymmetry was found in the shunt-treated hydrocephalic children, the direction of asymmetry being related to the laterality of the regulating shunt device. The most marked asymmetric changes were recorded in the maxillary and mandibular regions, probably due to the adaptive nature of these regions.

Basicranial changes in shunt-treated hydrocephalic children--a two-year report.

Basicranial changes were studied in a sample of 29 shunt-treated hydrocephalics, aged 7 to 18 years, by analyzing differences in angular relationships between structures seen on roentgenologic cephalograms taken at intervals of about 2 years following initial examination. In addition, the natural head position was recorded in 24 subjects at a follow-up examination. The cranial base among the boys showed increased flexure during the follow-up period. This finding was reflected in a decrease in the angle between the sphenoidal and clival planes and that of the nasion-sella-basion. Head posture, calculated in terms of the craniovertical and cervicohorizontal angles, was more forwardly flexed in the shunt-treated subjects than in the corresponding controls.

Craniofacial morphology in shunt-treated hydrocephalic children.

Craniofacial morphology was studied in a sample of 37 hydrocephalic subjects, 7 to 18 years of age, most of whom had had their first shunt operation performed in early childhood and were presently undergoing shunt treatment. The patients were grouped according to age and sex, and cephalometric radiograms were made. Similar radiograms from a north Finnish population and pretreatment radiograms from children having orthodontic cure were used as controls. The cephalograms were analyzed using linear, angular, and proportional measurements. Both cranial and facial morphological deviations were observed among the shunt-treated patients. The calvarium was thickened and the neurocranium enlarged; the cranial base flexure was increased, particularly among the older boys; and increased facial prognathism was observed. These craniofacial aberrations seemed to be exacerbated by a prolonged shunting time. A class I dental interrelation was found in all but two patients.