Cervical column morphology related to head posture, cranial base angle, and condylar malformation

The present study describes the cervical column as related to head posture, cranial base, and mandibular condylar hypoplasia. Two groups were included in the study. The 'normal' sample comprised 21 subjects, 15 females aged 23-40 years (mean 29.2 years), and six males aged 25-44 years (mean 32.8 years) with neutral occlusion and normal craniofacial morphology. The condylar hypoplasia group comprised the lateral profile radiographs of 11 patients, eight females, and three males, aged 12-38 years (mean 21.6 years). For each individual, a profile radiograph was taken to perform a visual assessment of the morphology of the cervical column. For the normal group only, the profile radiographs were taken in the standardized head posture to measure the head posture and the cranial base angle. Cervical column: Morphological deviations of the cervical column occurred significantly more often in the subjects with condylar hypoplasia compared with the normal group (P < 0.05 and P < 0.01, respectively). The pattern of morphological deviations was significantly more severe in the subjects with condylar hypoplasia compared with the normal group (P < 0.01). Cervical column related to head posture and cranial base: The cervicohorizontal and cranial base angles were statistically larger in females than in males (P < 0.05 and P < 0.01, respectively). No statistically significant age differences were found. Only in females was the cervical lordosis angle (OPT/CVT, P < 0.01), the inclination of the upper cervical spine (OPT/HOR, P < 0.05), and the cranial base angle (n-s-ba, P < 0.05) significantly positively correlated with fusion of the cervical column. These associations were not due to the effect of age.     

Oral breathing and head posture

OBJECTIVE: To determine the head posture and cephalometric characteristics in oral breathing children. MATERIALS AND METHODS: Lateral cephalograms taken in natural head posture of 35 oral breathing patients (OB) (mean age 8.8 +/- 2.2 years SD; range 5-13 years) and of 35 patients with varied malocclusions and physiological breathing (PB) (mean age 9.7 +/- 1.6 years SD; range 7-13 years) were examined. RESULTS: A Student's t-test showed that an increase in angles NSL/OPT (P = .000), NSL/CVT (P = .001), FH/OPT (P = .000), FH/CVT (P = .005), and NSL/VER (P = .000); a decrease in the distance MGP-CV1p (P = .0001); and a decrease in the angles MGP/OP (P = .000) and OPT/ CVT (P = .036) were found in the OB group. A low position of the hyoid bone (H-MP, P = .009), a major skeletal divergence (ANS-PNS/Go-Me, P = .000), and an increased value of the ANB angle (P = .023) were present in OB patients. To ascertain if the changes in posture were connected with posterior obstruction of the upper respiratory airways, the OB group was divided into two subgroups based on the distance Ad2-PNS being greater than or less than 15 mm. No significant differences were found between these two groups. CONCLUSIONS: Our data suggest that OB children show greater extension of the head related to the cervical spine, reduced cervical lordosis, and more skeletal divergence, compared with PB subjects.     

Changes in head posture after rapid maxillary expansion in mouth-breathing girls: a controlled study

The influence of respiratory function on craniofacial development and head posture has been demonstrated previously. This study evaluated the effect of rapid maxillary expansion (RME) on nasopharyngeal airway adequacy, head posture, and facial morphology in children with nasal obstruction. Fifty-five girls (8-15 years of age) who needed maxillary expansion, showed reduced nasopharyngeal airway adequacy (pm-Ad 2), and were subjectively assessed as mouth breathers were allocated randomly into 2 groups. The 23 subjects in the first group were treated with RME, and the 22 subjects in the other group were followed about 8 months before beginning therapy and became untreated controls. Dental casts and lateral skull radiographs exposed in natural head position were obtained at the first visit and 6 months later for all subjects. In the girls under active treatment there was a statistically significant increase of pm-Ad 2 (P < .0001), a significant increase of the cervical lordosis angle (P < .0001), a flexion of the head (P < .0001), and a decrease in the craniocervical angulation (P < .0001) (paired t-tests). No significant changes were seen in the control group. The correlation coefficients indicated a mild correlation between pm-Ad 2 distance and craniocervical angulation (SN/OPT angle) (r = 0.61 at P < .001). RME is capable of increasing nasopharyngeal airway adequacy in girls, and this leads to a decrease in craniocervical angulations. The clinical importance of these results is yet to be clarified.     

Cervical lordosis angle measured on lateral cephalograms; findings in skeletal class II female subjects with and without TMD: a cross sectional study

The literature reports evidence of various types of correlations between cervical alterations and cervical pain, and the existence of cervical pain in subjects with temporomandibular joint internal derangement (TMD). The hypothesis of this study is that cervical lordosis angle (CVT/EVT angle) alteration on cephalometrics could be correlated to the presence of TMD. The cephalometric records of 50 females with documented TMD were compared with those of a control group of 50 females. The subjects in the sample were 25-35 years of age, average 28.9 years (SD, 3.2). Radiographs were taken in mirror position, and seventeen variables, including the CVT/EVT angle, were traced. Double measurements were made to evaluate method error using Dahlberg's formula. Pearson's correlation coefficient and Mann-Whitney's t-test were used to evaluate the data. Intra-group analysis showed significant correlations between the CVT/EVT angle and mandibular length (p<0.01), mandibular position (p<0.05), mandibular divergence (p<0.01), and overjet (p<0.01) in both groups. Between groups, the analysis showed significant differences in CVT/EVT angle (p<0.05), maxillary protrusion (p<0.01), mandibular protrusion (p<0.01), mandibular length (p<0.01), mandibular divergence (p<0.05), and overbite (p<0.05).     

An investigation of mandibular morphology in subjects with different vertical facial growth patterns

In the present study, mandibular morphology was investigated on lateral cephalometric head films and dental casts of 60 subjects (30 females and 30 males) who had different vertical facial growth patterns. The sample had a mean age of 13.5 years, with a range of 11 to 15.5 years. The subjects were divided into three groups with regard to vertical facial growth by using the SN/GoGn angle to define low-angle, normal, and high-angle groups. In addition, each group was divided into two subgroups according to sex. The effects of the SN/GoGn angle and gender on mandibular morphology were investigated by means of analysis of variances. Tan Go, IMPA, SL, and EL measurements were found to be related to SN/GoGn, and the measurements of Go-Gn, Symphysis depth, and Intermolar width to be related to sex.     

Evaluation of cervical spine posture after functional therapy with FR-2: a longitudinal study

The authors compared postural changes produced in 20 Caucasian female children treated with the Frankel Functional Regulator appliance (FR-2) (Frankel Industries, Morangis Cedex, France) using cephalometric tracings and comparing the tracings to 20 untreated Class II controls from the University of Chieti. Each patient in the study group was treated for exactly two years by the same operator using the FR-2 appliance and a standardized design and clinical technique, including prefunctional orthodontics where indicated. The average starting age was 8.4 yrs. (SD+/-2.1). At the end of the therapy, the average age was 10.3 yrs. (SD+/-2.4). Two teleradiographs were made of each patient: the first one at the beginning of treatment and the second one after six months. The radiographs were taken with the subjects standing in the ortho-position with no ear rods in the cephalostat; mirror position was carried out. In order to detect errors due to landmark identification, duplicate measurements were made using ten radiographs, and the error variance was calculated using Dahlberg's formula. Thirty-seven variables were studied. The cervical lordosis angle (CVT/EVT) was significantly higher in the study group as compared to the control group (p<0.05) at the end of treatment, probably due to a significant backward inclination of the upper segment of the cervical column (OPTNer and CVTNer) in the treated group (p<0.001 and p<0.01) from pre- to posttreatment. There was no significant change in the lower segment of the cervical column inclination (EVT/Ver). The changes resulted in a weak association in the multiple regression model to an increasing of maxillary base length and mandibular protrusion (R2=0.272; p<0.05). Other variables in the multiple regression were not significant.     

Associations between thoracic kyphosis, head posture, and craniofacial morphology in young adults

The aim of the present study was to investigate associations between thoracic hyper- and hypokyphosis, head posture, and craniofacial morphology in young adults. Using forward bending test and spinal pantographic measurements, 31 subjects, 16 with thoracic hyper- and 15 with hypokyphosis, were selected from a population-based cohort of 430 young adults. Lateral roentgen-cephalograms were taken in natural head posture and craniofacial and postural angular measurements were calculated. Any statistically significant differences between the groups thoracic hyperkyphosis and thoracic hypokyphosis--were analysed using Student's t test. Subjects with thoracic hyperkyphosis had a larger atlantocervical angle (At/ CVT, P < 0.01) than subjects with thoracic hypokyphosis. However, head position (NSL/VER) was similar in both groups, probably owing to the visual perception control of craniovertical relation. There was no statistically significant difference in craniofacial morphologyy between the groups.     

Associations between thoracic kyphosis,head posture,and craniofacial morphology in young adults

The aim of the present study was to investigate associations between thoracic hyper- and hypokyphosis, head posture, and craniofacial morphology in young adults. Using forward bending test and spinal pantographic measurements, 31 subjects, 16 with thoracic hyper- and 15 with hypokyphosis, were selected from a population-based cohort of 430 young adults. Lateral roentgen-cephalograms were taken in natural head posture and craniofacial and postural angular measurements were calculated. Any statistically significant differences between the groups - thoracic hyperkyphosis and thoracic hypokyphosis - were analysed using Student's t test. Subjects with thoracic hyperkyphosis had a larger atlantocervical angle (At/CVT, P &lt; 0.01) than subjects with thoracic hypokyphosis. However, head position (NSL/VER)was similar in both groups, probably owing to the visual perception control of craniovertical relation. There was no statistically significant difference in craniofacial morphology between the groups.     

Evaluation of cervical posture following palatal expansion: a 12-month follow-up controlled study

This study evaluated the effects of rapid palatal expansion (RPE) on nasopharyngeal airway size, head posture, and cervical curvature angle in children with nasal obstruction. The patients were 45 female subjects (8-15 years of age) who had a reduced nasopharyngeal airway size and were subjectively assessed as being mouth breathers and requiring palatal expansion. They were randomly allocated to one of two groups: 23 subjects in the first group were treated with RPE, while the 22 subjects in the other group were monitored for approximately 14 months prior to commencing therapy, and became untreated controls. Lateral skull radiographs, taken in the natural head position, were obtained at the first visit (T0) and 6 (T1) and 12 (T2) months later for all subjects. The differences between the cephalometric variables at baseline and after 6 and 12 months were evaluated with a one-way repeated measures analysis of variance. Where significant interactions were found, a Bonferroni corrected paired Student's t-test was performed for pairwise comparisons. Changes in cephalometric variables within the experimental groups were tested by paired Student's t-tests as a post hoc procedure. Finally, a correlation matrix, using the Pearson correlation coefficient, was computed in order to evaluate the relationship between the change in airway adequacy and (1) the amount of maxillary expansion, (2) chronological age, (3) the amount of time that the appliance was activated, and (4) morphological and postural measurements of the face. At T1, children under active treatment showed a statistically significant increase in nasopharyngeal airway size, cervical curvature angle, and flexion of the head, together with a significant decrease in craniocervical angulation (all P < 0.05). These changes were all found to be stable at T2. No significant changes were seen in the control group. The correlation coefficients indicated a significant correlation between nasopharyngeal airway size and craniocervical angulation (SN/OPT angle; r = -0.61, P < 0.05). The findings indicate that RPE is capable of increasing nasopharyngeal airway size in young females, which results in a decrease in craniocervical angulation. Clinically, the findings seem to suggest that improvement of respiratory function could result in a change in head posture.     

Evaluation of changes in the vertical facial dimension with different anchorage systems in extraction and non-extraction subjects treated by Begg fixed appliances: a retrospective study

The aim of the study was to evaluate and compare the effects of mesial movement of the maxillary and mandibular molars on the facial vertical dimensions following orthodontic treatment. Patients with an Angle Class I malocclusion were treated by four first premolar extractions and Begg fixed appliances (moderate and maximum anchorage groups), while those with an Angle Class II malocclusion were treated by Begg intraoral distalization mechanics without extractions (distalization group). Following treatment, the patients were grouped according to the mesial movement of the mandibular first molars and compared with an Angle Class I control group. All groups comprised 15 patients, their mean pre-treatment ages were 14.95 years for the moderate (13 females, 2 males), 14.88 years for the maximum (13 females, 2 males), 14.41 years for the distalization (10 females, 5 males), and 14.38 years for the control (13 females, 2 males) groups. Lateral cephalometric measurements were performed at two time points (T(1): pre-treatment/control, T(2): post-treatment/control). A paired t-test was used for within-group comparisons and non-parametric Kruskal-Wallis and Dunn's multiple-comparison tests to determine any differences. The increases in anterior and posterior face heights were similar between groups. The mandibular plane angle (SN/GoGn) was increased in all treatment groups, while it decreased in the control group. Although SN/GoGn increased more in the distalization and less in the moderate anchorage groups, these differences were not statistically significant. The change in SN/GoGn was significantly different only between the distalization and control groups. Facial vertical dimensions were not significantly affected by the amount of mesial movement of the molar teeth.     

The association between posture of the head and malocclusion in Saudi subjects

The purpose of the present study was to examine whether a relationship exists between posture of the head and neck, and the presence of certain malocclusal problems. Dental models, in addition to lateral cephalometric radiographs, taken in the "natural head position" of 180 male and female subjects were obtained. The postural angles between the head and the cervical column, termed craniovertical, craniocervical, cervicohorizontal, and cervical curvature, were measured. The malocclusal traits studied were: molar relation, crowding, spaces, overbite, overjet, crossbites, and midline displacements. Results show that a relationship between crowding and head posture could only be found in subjects with upper arch crowding and cervical curvature (p<0.01). A significant difference in craniocervical and cervicohorizontal angles was observed in subjects with overbite, compared to subjects without overbite (p<0.01, p<0.001). The influence of gender on overbite and head posture was also found to be strongly correlated (p<0.05). With regard to molar relation, Class II malocclusion showed a stronger relation with craniovertical and cervicohorizontal angles than both other classes (p<0.05, p<0.01). A significant correlation was found between craniovertical angles NSL/VER and overjet, irrespective of gender or age (p<0.05). Crossbite was strongly correlated with all craniocervical angles (p<0.05). It can be concluded that certain malocclusal problems are more strongly associated with head posture than others, and that crowding does not seem to play a major role in this association in the present study.     

Effects of anterior cruciate ligament (ACL) injury on postural control and muscle activity of head, neck and trunk muscles

The aim of the study was to evaluate the effects that an anterior cruciate ligament injury of the knee has on postural control and activity of neck, head and trunk muscles to investigate the existence of connections between the masticatory system and body posture. Surface electromyographic activity of the muscles at mandibular rest position, and during maximal voluntary clenching and posturometric and stabilometric measurements of 25 adult patients having pathology on the left knee were compared with a control non-pathological group. At rest, the patients showed a higher muscular activity of anterior temporalis, masseter, sternocleidomastoid and lower trapezius, compared with the control subjects (P < 0.05). At maximal voluntary clenching, the patients showed a lower muscular activity of the right anterior temporalis and masseter and a higher muscular activity of the lower trapezius, compared with the control subjects. For the stabilometric measurements, all the subjects showed a significant reduction in the postural centre of pressure path length during the test with eyes open and cotton rolls, compared with the test with eyes closed and mandibular rest position (P < 0.05). In addition, the patients showed a significant displacement of the postural centre of pressure in a forward direction (P < 0.05) and into the right side (P < 0.05), compared with the control subjects. Anterior cruciate ligament injury appears to be associated to a change in the activity of head, neck and trunk muscles and to a change in the position of the postural centre of pressure. Cotton rolls seem to improve the stability of the subject.     

Lateral cephalometric analysis of the pharyngeal airway space affected by head posture

To clarify the relationship between head posture and pharyngeal airway space (PAS), the cephalometric parameters at different head postures were examined. Twelve normal Japanese adults (6 males and 6 females) were examined. Lateral cephalometric radiographs were taken at five different head postures in each person. All radiographs were traced, and the measurements were analyzed statistically. PAS was significantly increased by forward inclination of the cervical spine. The most significant correlation was found between the change in CVT/NSL (cranio-cervical inclination in the second and fourth vertebrae) and the change in PAS-TP (the minimal pharyngeal airway space) (r(2)=0.79 in males, r(2)=0.67 in females). The mean CVT/NSL when the head was in the natural (neutral) position was 100.9 degrees in males and 103.5 degrees in females. Linear regression analysis revealed DeltaPAS (mm)=0.37DeltaCVT/NSL (degree) (r(2)=0.79, p<0.0001) in males, and DeltaPAS (mm)=0.33DeltaCVT/NSL (degree) (r(2)=0.51, p<0.0001) in females. The correlation equations were obtained as follows: the corrected PAS (mm)=the actual PAS (mm)+0.37[100.9-the actual NSL/CVT (degree)] in males, and the corrected PAS (mm)=the actual PAS (mm)+0.33[103.5-the actual NSL/CVT (degree)] in females. These results will contribute to obtaining an accurate assessment of the PAS that should be corrected by the cranio-cervical inclination.     

Effect of low pull headgear on head position

Objective

To evaluate changes in head position following the use of low pull headgear (LHG) and compare these changes with an untreated control group.

Subjects and methods

The test group comprised pre-treatment and post-treatment lateral cephalograms of 30 males, aged 11 ± 1.5 years, who were receiving LHG therapy for correction of Class II malocclusion. Pre-observation and post-observation lateral cephalograms of 25 untreated male subjects, aged 11 ± 1.6 years, served as controls. The average treatment time for the treatment group was 12 ± 2.02 months and the average observation period for the control group was 11 ± 1.03 months. Four postural variables (NSL/CVT, NSL/OPT, CVT/HOR, OPT/HOR) were measured to evaluate the head position in all subjects pre- and post-observations.

Results

There was no significant difference in all the measurements concerning the head position within each group (p > 0.05). The mean differences of pre- and post-observations of 4 postural variables in the LHG group were 1.43, 0.9, −1.13, and −1.08, while those of the control group were 1.56, −0.32, −0.24, and 0.04, respectively. There was no significant difference between the headgear and control groups for any of the postural variables measured (p = 0.924, 0.338, 0.448, and 0.398, respectively).

Conclusions

Although postural variables showed considerable variability in both groups, head position exhibited no significant changes over a period of 11–12 months either in the control or headgear group.     

Evaluation of cervical posture of children in skeletal class I, II, and III

Previous studies on the relationship between morphological structure of the face and cervical posture have predominantly focused on vertical dimensions of the face. The aim of this study was to investigate whether there are significant differences in cervical posture in subjects with a different sagittal morphology of the face, i.e., a different skeletal class. One hundred twenty (120) children (60 males and 60 females, average age 9.5 yrs., SD+/-0.5) were admitted for orthodontic treatment. Selection criteria was: European ethnic origin, date of birth, considerable skeletal growth potential remaining and an absence of temporomandibular joint dysfunction (TMD). Lateral skull radiographs were taken in mirror position. Subjects were divided into three groups based on their skeletal class. The cephalometric tracings included postural variables. The most interesting findings were: 1. children in skeletal class III showed a significantly lower cervical lordosis angle (p<0.001) than the children in skeletal class I and skeletal class II; 2. children in skeletal class II showed a significantly higher extension of the head upon the spinal column compared to children in skeletal class I and skeletal class III (p<0.001 and p<0.01, respectively). This is probably because the lower part of their spinal column was straighter than those of subjects in skeletal class I and II (p<0.01 and p<0.001, respectively). Significant differences among the three groups were also observed in the inclination of maxillary and mandibular bases to the spinal column. The posture of the neck seems to be strongly associated with the sagittal as well as the vertical structure of the face.     

Effects of neuromuscular deprogramming on the head position

Objectives:

The aim of this study was to evaluate the effects of the neuromuscular deprogramming of the mandible on the craniocervical position.

Methods:

Participants (n?=?65) were separated into two groups: 25 untreated controls (10 men and 15 women) and 40 patients (17 men and 23 women) and underwent neuromuscular deprogramming with upper occlusal splints for an average of 6 months and 7 days, before orthodontic treatment. Lateral cephalograms were obtained from each subject in the natural head position (NHP), before and after neuromuscular deprogramming. Craniocervical cephalometric analysis was performed to evaluate craniovertical (NSL/VER), craniocervical (OPT/NSL and CVT/NSL), and cervicohorizontal (OPT/HOR and CVT/HOR) angulation, and the angle of the cervical curvature (OPT/CVT).

Results:

After neuromuscular deprogramming, significant changes in three angles — NSL/VER (P<0·001), OPT/NSL (P<0·001) and CVT/NSL (P<0·001) — were found between the two groups. For the cervical spine position, no significant changes were observed.

Conclusion:

The results indicate that neuromuscular deprogramming using occlusal splint causes significant extension of the head.     

Anterior open bite: a case–control study

Objective.  The aim of this study was to assess the influence of sucking habits and facial pattern measurements on the development of anterior open bite (AOB).
Methods.  A case–control study was carried out on 60 children aged 7 and 8 years attending municipal public schools in the city of Recife, Brazil. Data collection included interviews with guardians, oral examinations, and facial growth pattern analysis using cephalometric radiographs. The following cephalometric measurements were assessed: SN.Gn, SN.GoGn, FMA, and Facial Axis. Statistical analyses were performed using the Student's t -test and Pearson's chi-square test at a 5% level of significance.
Results.  The percentage of children with sucking habits in the case group was much higher than in the control group (53.3% vs 16.7%) ( P  = 0.003). Children with sucking habits were six times more likely to develop AOB. Regarding the measurements assessed, no statistically significant differences were observed between groups.
Conclusion.  This study found no evidence that variations in cephalometric angles (SN.Gn, FMA, SN.GoGn, and facial axis) are risk factors for AOB. Only sucking habits demonstrated a positive correlation with an increased AOB.     

Relation between cervical posture on lateral skull radiographs and electromyographic activity of masticatory muscles in caucasian adult women: a cross-sectional study

The aim of this study was to evaluate the association between cervical posture on lateral skull radiographs and surface electromyographic recordings (sEMG) of head and neck muscles. The sample comprised 40 Caucasian adult females, average age 26.8 (20-48); lateral skull radiographs were obtained in natural head position (mirror position). sEMG activity was bilaterally investigated for the following muscles: masseter, anterior temporalis, digastric, posterior cervical, sternocleidomastoid and upper and lower trapezius. All muscles were monitored at rest and during maximal voluntary clenching (MVC). A Pearson's correlation coefficient revealed significant correlations (P < 0.01) between cranio-cervical angulations and sEMG activity of masseter, digastric, lower trapezius, during MVC and anterior temporalis at rest. Significant correlations (P < 0.01) were also found between cervical lordosis angle and sEMG activity of masseter (during MVC) and lower trapezius (at rest). In view of transversal method, no conclusion was possible about the mechanism concerning these results. Future longitudinal studies should be directed to understand the extent of environmental and genotype influences by masticatory muscle activity on cervical posture.     

Class II mechanics and overbite

Class II mechanics are supposed to affect the vertical balance of the face when they are used in hyperdivergent patterns. We carried out a study about class II mechanics effects on 100 patients; 50 of them are hyperdivergent (GoGn/SN > or = 37), and 50 non-hyperdivergent. They all were treated with an Edgewise appliance without any high pull head gear. The authors showed that GoGn/SN angles and Occ/SN tend to be lessened in a skeletal open-bite population. Thus, Class II mechanics can be prescribed in any vertical facial pattern.     

Change in cranio-cervical angulation following orthognathic surgery

Changes in natural head posture (NHP) were investigated in 33 patients (10 males, 23 females) with an age range of 16-40 years (median 21 years) following orthognathic surgery to change vertical face height. The reproducibility of the radiographer's technique of taking radiographs in NHP was investigated using a photographic method and found to be acceptable. The patients were divided into two groups: group 1, patients who had more than 3 mm of vertical change in anterior total face height (ATFH) and group 2, those who had less than 3 mm vertical change.For group 1 there was a significant relationship between ATFH change and cranio-cervical angulation (NSL/OPT) change (r = 0.532, P = 0.023), compared with group 2 (r = -0.247, P = 0.376). A similar relationship was revealed between lower anterior face height (LAFH)/ATFH ratio and NSL/OPT, where the correlation was also higher in group 1 (r = -0.635, P = 0.005) compared with group 2 (r = -0.182, P = 0.515). The correlation between cranio-vertical angulation (NSL/VER) and ATFH was not significant for group 1 (r = 0.406) or group 2 (r = 0.239) patients. Additionally, NSL/VER and LAFH/ATFH correlation for the two groups was not significant (r = -0.392 and -0.338, respectively).There appears to be a relationship between the reduction in vertical face height following orthognathic surgery and neck posture (as indicated by NSL/OPT). As no significant relationship was found between the reduction in face height and head posture (as indicated by NSL/VER) this suggests that neck posture, rather than head posture, had changed.