Upper cervical spine and craniofacial morphology in hypohidrotic ectodermal dysplasia.

AIM: Morphological deviations in the upper cervical spine and craniofacial morphology in patients with X-linked hypohidrotic ectodermal dysplasia (XLHED) were compared to non-syndromic controls. METHODS: All children and adolescents with genetically verified XLHED, registered at the Resource Centres for Oral Health in Rare Diseases, who met the inclusion criteria, were included. The group thus comprised 15 XLHED patients (3 girls and 12 boys, aged 8-16 years, mean 11.2 years). The control group comprised 22 non-syndromic pre-orthodontic children (14 girls and 8 boys aged 9-16 years, mean 11.9 years) with agenesis of one tooth, neutral occlusion and normal craniofacial morphology. The craniofacial and upper spine morphology was analysed on lateral cephalograms by standard methods. Differences between XLHED patients and controls were tested and adjusted for age and gender by multiple regression analyses. RESULTS: Morphological deviations in the upper spine occur significantly more often in XLHED patients compared to controls (60 vs. 9.1%; p < 0.01). The cranial base angle (n-s-ar, p < 0.05), sagittal jaw relationship (ss-n-pg, p < 0.001), maxillary inclination (NSL/NL, p < 0.001) and mandibular inclination (NSL/ML, p < 0.01) were significantly smaller in XLHED patients compared to controls. The mandibular prognathia (s-n-pg) was significantly larger in XLHED patients compared to controls (p < 0.05). CONCLUSIONS: The upper spine and the craniofacial morphology were different in XLHED patients compared to controls. The results of this study may contribute to a further understanding of the craniofacial and spinal phenotypic spectrum in patients with XLHED and thus have implications for diagnosis and treatment planning of these patients.

Sleepiness, occlusion, dental arch and palatal dimensions in children attention deficit hyperactivity disorder (ADHD).

AIMS: This was to compare sleepiness, occlusion, dental arch and palatal dimensions between children with attention deficit hyperactivity disorders (ADHD) and healthy children (control group). METHODS: 15 children with ADHD (10 boys, 5 girls, mean age 10.98 years) and 36 healthy age matched children (21 boys, 15 girls, mean age 10.60 years) were included. Intra-oral three-dimensional scans of the teeth and palate were performed to evaluate the occlusion, dental arch and palatal dimensions. Sleepiness was evaluated from the questionnaires. The differences between the two groups were analysed by Fisher's exact test and general linear models adjusted for age and gender. RESULTS: The ADHD children had a significantly narrower dental arch at the gingival level of the canines (p < 0.05) and a tendency to increased prevalence of posterior cross-bite compared to the controls (13.3 vs. 0.0%, p = 0.086). The ADHD children snored significantly more (p < 0.05) and slept restlessly significantly more often (p < 0.0005) compared to the controls. The ADHD children had a tendency to sleep fewer hours during the night (p = 0.066) and felt inadequately rested in the morning (p = 0.051) compared to the controls. CONCLUSION: The results indicate that sleepiness and palatal width, especially the more anterior skeletal part of the palate, may be affected in children with ADHD. The results may prove valuable in the diagnosis and treatment planning of children with ADHD. Further studies are needed to investigate sleep and dental relations in children with ADHD.

Positional changes of maxillary central incisors following orthodontic treatment using single-crown implants as fixed reference markers.

OBJECTIVES: This follow-up study (1) compares tooth displacement of central incisors in patients with and without pre-implant orthodontic treatment and (2) investigates whether sex, age, or orthodontic retention have an effect on tooth displacement after the insertion of single-crown implants. MATERIALS AND METHODS: Fifty-seven patients - thirty-seven with (test group) and twenty without pre-implant orthodontic treatment (control group) - were rehabilitated with 89 single-crown implants in the upper maxilla. Clinical and radiographic data, clinical photographs, and dental casts were collected during baseline examinations after prosthetic rehabilitation and at the final follow-up examination at least 5 years later. A total of 114 dental casts were digitalized and aligned using a software program to measure changes in the positions of the central incisors. RESULTS: After a follow-up period of at least five years, 87% of the central incisors measured in the test group were displaced >0.25 mm vertically compared with 70% in the control group. Seventy-eight percent of the test group teeth had moved >0.25 mm horizontally compared with 55% in the control group. These differences were not significant, and there were no significant correlations with patient age or sex. CONCLUSION: The majority of patients had minor vertical (60%) or horizontal (67%) tooth displacement of the central incisors (0.25-0.75 mm) after a minimum follow-up period of 5 years. This study found no significant differences in tooth displacement comparing patients with and without pre-implant orthodontic treatment. No significant effect of sex, age, orthodontic retention, or implant location was observed on tooth displacement.

Long-term side effects on the temporomandibular joints and oro-facial function in patients with obstructive sleep apnoea treated with a mandibular advancement device.

Patients with obstructive sleep apnoea (OSA) in long-term treatment with a mandibular advancement device (MAD) to increase the upper airway space may develop changes in the temporomandibular joint (TMJ) and the oro-facial function due to the protruded jaw position during sleep. The aim was to investigate the influence of long-term MAD treatment on the TMJs, oro-facial function and occlusion. This prospective study included 30 men and 13 women (median age 54) with OSA [Apnoea-Hypopnoea Index (AHI): 7-57]. They were examined with the Nordic Orofacial Test Screening (NOT-S), the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) and cone beam computed tomography (CBCT) of the TMJs. The examination was performed before MAD treatment (T0), and 3-6 months (T1, no CBCT), 1 year (T2) and 3 years (T3) after treatment start. The results were analysed as long term (T0-T3, n = 14) and short term (T0-T2, n = 24) by t-test, Fisher's exact test and anova. Both long- and short-term analyses revealed a reduction in AHI (P < 0·002). Significant long term were increased scores in the NOT-S Interview (P < 0·045), reduced vertical overbite (P < 0·031) and increased jaw protrusive movement (P < 0·027). TMJ changes were found as joint sounds in terms of reciprocal clicking and crepitus, short term as a decrease and subsequent recurrence (P < 0·053; P < 0·037). No significant radiological changes were found. In conclusion, MAD treatment is beneficial to some OSA patients, but might induce changes in the TMJs, the oro-facial function and the occlusion. However, these changes seemed to be less harmful than previously reported with careful adaptation, control and follow-ups.

Proposal of new upper airway margins in children assessed by CBCT.

OBJECTIVES: Recently, studies have performed three-dimensional analyses of upper airways in children. However, there was a lack of airway delineation according to anatomical boundaries and/or easily mobile soft-tissue landmarks were used. The aim of the present study was to define new upper airway margins in children on CBCT according to anatomical bony landmarks and to validate the method. METHODS: 25 scans were randomly selected from a larger database containing CBCT scans of children prior to orthodontic treatment (14 girls and 11 boys; mean age, 10.9 ± 2.5 years). Scans were evaluated by two observers. Specific head positioning and virtual orientation protocols were adopted and greyscale thresholding was established for each patient. Volume and minimum cross-sectional area of the oropharynx were calculated. Intra- and interobserver reliability were assessed by reassessment of the CBCTs 2 weeks later. RESULTS: The new airway margins were defined superiorly by a line passing through the palatal plane (anterior nasal spine to posterior nasal spine) extending to the posterior wall of the pharynx, inferiorly by a line passing from the anterosuperior edge of C4 to menton, anteriorly by a line passing from the soft palate to menton, posteriorly and laterally by the respective pharyngeal walls. Method error for airway volume and minimal cross-sectional area was ≤2.00%, and intra- and interobserver reliability ranged from 0.99 to 1.00. CONCLUSIONS: The proposed protocol utilizes easily identifiable bony landmarks to delineate the upper airway on cone beam scans of children and was found to be reliable and reproducible.

Morphological characteristics of frontal sinus and nasal bone focusing on bone resorption and apposition in hypophosphatemic rickets.

OBJECTIVES: To characterize the size and the morphology of the frontal sinus (i.e., structure evolved by bone resorption) and the nasal bone (i.e., structure evolved by bone formation) in adults with hypophosphatemic rickets (HR) compared with controls. SETTING AND SAMPLE POPULATION: Thirty-six patients with HR (12 males and 24 females) aged 21-74 years were included. The control group comprised 49 healthy individuals (23 males and 26 females) aged 20-79 years. MATERIAL AND METHODS: Profile cephalograms were obtained and the following measurements were included: height and width of the frontal sinus; length, width, and area of the nasal bone. The morphology of the nasal bone was assessed. Linear regression analyses were used to compare HR patients with controls. RESULTS: In HR patients, the size of the frontal sinus was unaffected (p = 0.406 to p = 0.862). The proximal width of the nasal bone, and the ratio between the proximal width and the axial length of the nasal bone were increased in HR patients (p < 0.05). CONCLUSIONS: The size of the frontal sinus was unaffected, indicating a normal ability of bone resorption within the bone. The morphology of the nasal bone was abnormal indicating a disturbance in bone formation during growth. The disturbances in nasal bone modeling were mainly expressed in the proximal part supported by structures of cartilaginous origin.

Cervical vertebral column morphology in patients with obstructive sleep apnoea assessed using lateral cephalograms and cone beam CT. A comparative study.

OBJECTIVES: Few studies have described morphological deviations in obstructive sleep apnoea (OSA) patients on two-dimensional (2D) lateral cephalograms, and the reliability of 2D radiographs has been discussed. The objective is to describe the morphology of the cervical vertebral column on cone beam CT (CBCT) in adult patients with OSA and to compare 2D lateral cephalograms with three-dimensional (3D) CBCT images. METHODS: For all 57 OSA patients, the cervical vertebral column morphology was evaluated on lateral cephalograms and CBCT images and compared according to fusion anomalies and posterior arch deficiency. RESULTS: The CBCT assessment showed that 21.1% had fusion anomalies of the cervical column, i.e. fusion between two cervical vertebrae (10.5%), block fusions (8.8%) or occipitalization (1.8%). Posterior arch deficiency occurred in 14% as partial cleft of C1 and in 3.5% in combination with block fusions. The agreement between the occurrence of morphological deviations in the cervical vertebral column between lateral cephalograms and CBCT images showed good agreement (κ = 0.64). CONCLUSIONS: Prevalence and pattern in the cervical column morphology have now been confirmed on CBCT. The occurrence of morphological deviations in the cervical vertebral column showed good agreement between lateral cephalograms and CBCT images. This indicates that 2D lateral cephalograms (already available after indication in connection with, e.g. treatment planning) are sufficient for identifying morphological deviations in the cervical vertebral column. For a more accurate diagnosis and location of the deviations, CBCT is required. New 3D methods will suggest a need for new detailed characterization and division of deviations in cervical vertebral column morphology.

How does occipitalization influence the dimensions of the cranium?

OBJECTIVES: To describe occipitalization on human dry skulls and to compare craniofacial morphology including the posterior cranial fossa in skulls with occipitalization and in skulls without occipitalization and with normal craniofacial morphology (controls). SETTING AND SAMPLE POPULATION: A total of 29 skulls were selected from the Björk collection. Nine had occipitalization of atlas. Twenty had no dentoalveolar or craniofacial anomalies, and no occipitalization was visible on the skulls (controls). The ages of the skulls were between adolescence and adulthood. METHODS: Visual assessments to describe the occipitalization pattern, direct measurements to measure the foramen magnum dimensions and cephalometric radiographic analyses to describe the craniofacial morphology. New variables were determined to describe the posterior cranial fossa. RESULTS: Of the skulls with occipitalization, 67% had complete and 33% had partial occipitalization. In the posterior part of the neural arch, 44% had a cleft. Occipitalization was significantly associated with a small foramen magnum (p < 0.01; p < 0.001) and deviant shape of the posterior cranial fossa (p < 0.05). The craniofacial morphology in the vertical and sagittal dimensions including the cranial base angle was normal in skulls with occipitalization, which indicates that occipitalization is associated with deviant morphology of the surrounding bony structures but not with deviations in the craniofacial morphology in general. The results of this study are important for the diagnosis of occipitalization on 2D radiographs.

Associations between the Cervical Vertebral Column and Craniofacial Morphology.

Aim. To summarize recent studies on morphological deviations of the cervical vertebral column and associations with craniofacial morphology and head posture in nonsyndromic patients and in patients with obstructive sleep apnoea (OSA). Design. In these recent studies, visual assessment of the cervical vertebral column and cephalometric analysis of the craniofacial skeleton were performed on profile radiographs of subjects with neutral occlusion, patients with severe skeletal malocclusions and patients with OSA. Material from human triploid foetuses and mouse embryos was analysed histologically. Results. Recent studies have documented associations between fusion of the cervical vertebral column and craniofacial morphology, including head posture in patients with severe skeletal malocclusions. Histological studies on prenatal material supported these findings. Conclusion. It is suggested that fusion of the cervical vertebral column is associated with development and function of the craniofacial morphology. This finding is expected to have importance for diagnostics and elucidation of aetiology and thereby for optimal treatment.

Skull thickness in patients with clefts.

OBJECTIVES: The purpose was to analyze skull thickness in incomplete cleft lip (CL), cleft palate (CP), and combined cleft lip and palate (UCLP). SETTING AND SAMPLE POPULATION: Copenhagen School of Dentistry and Copenhagen Cleft Lip and Palate Centre. Patients with cleft lip, cleft palate, and combined cleft lip and palate and normal adult men. MATERIAL AND METHODS: Four groups of patients comprised the study. One group of patients with CL (24 patients; 7 women, mean age 6; 17 men, mean age 7.1), one group of patients with UCLP (28 patients; 11 women, mean age 6.6; 17 men, mean age 6.7), one group of patients with CP (57 male patients aged 18-33), and one normal adult male control group. The CL and UCLP groups were compared. The CP group was compared with the normal adult male control group. RESULTS: CL women had a significantly thinner occipital bone compared with CL men (p = 0.027). Women with UCLP had significantly thicker occipital bone than the control women (incomplete CL) (p = 0.014). The study showed gender differences in skull thickness in different cleft types. It also demonstrated that particularly the occipital bone deviated in patients with UCLP, which may explain the considerable deviations in jaw shape and position, previously registered in patients with UCLP.

Skull thickness in patients with skeletal Class II and Class III malocclusions.

OBJECTIVES: To measure skull thickness in a group of subjects with skeletal Class II and a group with skeletal Class III malocclusion and compare these results with a group with Class I occlusion. SETTING AND SAMPLE POPULATION: Department of Orthodontics, School of Dentistry, University of Copenhagen. The Class II group comprised 25 females aged 17-42 (mean 26.0). The Class III group comprised 53 patients, 29 females aged 17-39 (mean 24.2) and 24 males aged 17-38 (mean 22.6). The control group comprised 39 subjects, 19 females and 20 males, aged 22-30, with a neutral occlusion and normal vertical and sagittal jaw relationship. MATERIAL AND METHODS: The thickness of the frontal, parietal and occipital bones was measured on lateral radiographs of patients with skeletal Class II and Class III and compared with the control group. Method error ranged from 0.30 to 0.60 mm and reliability coefficients from 0.79 to 0.97. Unpaired t-tests were used for evaluating differences in thickness. RESULTS: Females with skeletal Class II malocclusion had a significantly thinner occipital bone and thicker frontal bones than the control females. Skull thickness in Class III malocclusion was comparable to the control group. CONCLUSION: The most important outcome of this study was reduced skull thickness in the occipital area and thickening of the frontal bone in females with skeletal Class II malocclusion compared with females with Class I. Deviations in the theca cranii are thus associated with skeletal Class II malocclusions.

The neurocranial and craniofacial morphology in children with solitary median maxillary central incisor (SMMCI).

OBJECTIVES: The purpose of this study was to describe the neurocranial and craniofacial morphology on profile radiographs of children with single median maxillary central incisor (SMMCI). DESIGN: Cephalometric analyses of neurocranium and craniofacial morphology on profile radiographs. SETTING AND SAMPLE POPULATION: Department of Orthodontics, School of Dentistry, University of Copenhagen. Thirteen children with SMMCI, 12 girls and one boy (7-17 years of age). OUTCOME MEASURE: Cephalometric measurement were compared with normal standards using a paired t-test and Wilcoxon signed rank test. RESULTS: The size of the neurocranium (especially the length of the anterior cranial base), the maxillary prognathia, the maxillary inclination, the mandibular prognathia and the inclination of the mandibular incisors are significantly reduced in SMMCI. The mandibular inclination, the vertical jaw relationship, the alveolar bone prognathia in the upper jaw and the mandibular angle are significantly enlarged in SMMCI. CONCLUSION: The present study showed that occurrence of SMMCI is a sign of a developmental anomaly associated with deviations in neurocranial size and shape and in craniofacial morphology.

Skull thickness in patients with skeletal deep bite.

OBJECTIVES: Skull thickness in relation to patients with skeletal deep bite has not been reported previously. The present study examines the skull thickness in patients with skeletal deep bite and compares it with the skull thickness in subjects with neutral occlusion and normal craniofacial morphology. DESIGN: A retrospective case-control study. SETTING AND SAMPLE POPULATION: The material comprised 36 patients divided into two groups, a group of 18 patients with skeletal deep bite (eight females, 10 males) and a control group of 18 subjects (eight females, 10 males) with neutral occlusion and normal craniofacial morphology. OUTCOME: Skull thickness measurements. RESULTS: No significant gender differences were found regarding skull thickness. The skull was thicker in the deep bite group compared with the group with neutral occlusion and normal craniofacial morphology (p < 0.05). CONCLUSION: The present study demonstrates that patients with skeletal deep bite have a significantly thicker skull than subjects with neutral occlusion and normal vertical craniofacial morphology. This is considered important for the treatment planning for orthodontic and orthognathic patients.

Cervical column morphology in patients with skeletal open bite.

OBJECTIVES: To examine and compare the cervical column morphology in adult patients with skeletal open bite with the cervical column morphology of an adult control group with neutral occlusion and normal craniofacial morphology. DESIGN: A retrospective case-control study. SETTING AND SAMPLE POPULATION: Thirty-eight open bite patients, 27 women, aged 17-39 years, and 11 males, aged 18-40 years were compared with 21 controls, 15 females, aged 23-40 years, and six males aged 25-44 years from profile radiographs. OUTCOME MEASURE: From each individual a visual assessment of the cervical column and angular measurements of the craniofacial dimensions were performed on profile radiographs. RESULTS: In the open bite group 42.1% had cervical column body fusion, and 13.2% had posterior arch deficiency. The fusion always occurred between C2 and C3. Cervical column deviations occurred significantly more often in the open bite group compared with the control group (p < 0.05). Associations were found between fusions of the cervical column and maxillary retrognathia (p < 0.05), large maxillary inclination (p < 0.05) and large cranial base angle (p < 0.05). Associations were also found between posterior arch deficiency and maxillary retrognathia (p < 0.05) and cranial base angle (p < 0.05). The craniofacial parameter most important for the fusions and posterior arch deficiency was the maxillary retrognathia (p < 0.01, R (2) = 0.20; p < 0.05, R (2) = 0.26, respectively). CONCLUSION: - New associations between skeletal open bite and cervical column deviations are described. It is suggested that this knowledge is incorporated in future diagnostic and orthodontic treatment planning.

Temporomandibular disorders in relation to craniofacial dimensions, head posture and bite force in children selected for orthodontic treatment.

The present study examined the associations between craniofacial dimensions, head posture, bite force, and symptoms and signs of temporomandibular disorders (TMD). The sample comprised 96 children (51F, 45M) aged 7-13 years, sequentially admitted for orthodontic treatment of malocclusions entailing health risks. Symptoms and signs of TMD were assessed by 37 variables describing the occurrence of headache and facial pain, clicking, jaw mobility, tenderness of muscles and joints, and the Helkimo Anamnestic and Dysfunction indices. Craniofacial dimensions (33 variables), and head and cervical posture (nine variables) were recorded from lateral cephalometric radiographs taken with the subject standing with the head in a standardized posture (mirror position). Dental arch widths were measured on plaster casts and bite force was measured at the first molars on each side by means of a pressure transducer. Associations were assessed by Spearman correlations and multiple stepwise logistic regression analyses. The magnitudes of the significant associations were generally low to moderate. On average, temporomandibular joint (TMJ) dysfunction was seen in connection with a marked forward inclination of the upper cervical spine and an increased craniocervical angulation, but no firm conclusion could be made regarding any particular craniofacial morphology in children with symptoms and signs of TMJ dysfunction. Muscle tenderness was associated with a 'long face' type of craniofacial morphology and a lower bite force. Headache was associated with a larger maxillary length and increased maxillary prognathism. A high score on Helkimo's Clinical Dysfunction Index was associated with smaller values of a number of vertical, horizontal, and transversal linear craniofacial dimensions and a lower bite force.

Bite force in pre-orthodontic children with unilateral crossbite.

In the present study bite force was examined in pre-orthodontic children with unilateral posterior crossbite and compared with an age- and sex-matched control group. The sample comprised 52 children aged 7-13 years, 26 pre-orthodontic children with unilateral posterior crossbite (crossbite group), and 26 children with neutral occlusion (control group). Unilateral bite force was measured at the first molar by means of a pressure transducer. Furthermore, symptoms and signs of temporomandibular disorders (TMD) and number of teeth in contact in the intercuspal position (ICP) were recorded. In both groups, the maximum bite force increased significantly with age and with increasing stages of dental eruption, but the bite force in both sexes did not differ significantly. There were no significant differences in bite force between sides, but this was significantly smaller in the crossbite group than in the controls (P < 0.001). Regression analysis showed that stage of dental eruption (P < 0.001), number of teeth in occlusal contact (P < 0.01), and unilateral crossbite (P < 0.001) were the only variables significantly correlated with bite force. The number of teeth in contact was significantly smaller in the crossbite group than in the controls (P < 0.05) and the frequency of muscle tenderness was significantly higher in the crossbite group than in the controls (P < 0.05). These results suggest that differences in the muscle function associated with unilateral crossbite lead to a significantly smaller bite force in the crossbite group compared with controls and this difference did not diminish with age and development. These findings indicate that early treatment of unilateral posterior crossbite is advisable to optimize conditions for function.

The prenatal cranial base complex and hand in Turner syndrome.

From early childhood, Turner syndrome patients have a flattened cranial base, maxillary retrognathism, and short hands. There are, however, no studies that show when these genotype-determined abnormalities occur prenatally. The purpose of the present study was to measure craniofacial profile and hand radiographs of second trimester foetuses with Turner syndrome and compare the results with similar measurements from normal foetuses. The subjects consisted of 12 Turner syndrome foetuses, gestational age (GA) varying between 15 and 24 weeks, and crown-rump length (CRL) between 108 and 220 mm. The mid-sagittal block of each cranium was analysed as part of the requested brain analysis (pituitary gland analysis). This block and the right hand from seven foetuses were radiographed, and the skeletal maturity of the cranial base complex, i.e. the cranial base and the maxilla, was evaluated from the profile radiographs. Shape and size measurements in the cranial base were performed, and compared with normal values according to cranial maturity and to CRL. The cranial base angle in Turner syndrome was greater and the maxillary prognathism was reduced compared with the normal group. The dimensions in the cranial complex and in the hand showed that the bone lengths and distances in relation to CRL were generally smaller compared with normal foetuses. This investigation showed that the abnormal shape of the cranial base complex and the short hands in Turner syndrome are present prenatally.

Malocclusion traits and symptoms and signs of temporomandibular disorders in children with severe malocclusion.

The present study reports the prevalence of the various traits of malocclusion, as well as the occurrence of associations between malocclusion, and symptoms and signs of temporomandibular disorders (TMD) in children selected for orthodontic treatment by the new Danish procedure for screening the child population for severe malocclusions entailing health risks. The sample comprised 104 children (56 F, 48 M) aged 7-13. Malocclusion traits were recorded at the time of selection, symptoms and signs of TMD were recorded at recall. The most prevalent malocclusion traits were distal molar occlusion (Angle Class II; 72 per cent), crowding (57 per cent), extreme maxillary overjet (37 per cent) and deep bite (31 per cent). Agenesis or peg-shaped lateral teeth were observed in 14 per cent of the children. The most prevalent symptom of TMD was weekly headache (27 per cent); the most prevalent signs of TMD were tenderness in the anterior temporal, occipital, trapezius, and superficial and profound masseter muscles (39-34 per cent). Seven per cent of the children were referred for TMD treatment. The Danish TMD screening procedure was positive in 26 per cent, while 20 per cent had severe symptoms (Aill), and 30 per cent had moderate signs (Dill) according to Helkimo (1974). Symptoms and signs of TMD were significantly associated with distal molar occlusion, extreme maxillary overjet, open bite, unilateral crossbite, midline displacement, and errors of tooth formation. The analysis suggests that there is a higher risk of children with severe malocclusions developing TMD. Errors of tooth formation in the form of agenesis or peg-shaped lateral teeth showed the largest number of associations with symptoms and signs of TMD; these associations have not previously been reported in the literature.

Head posture and malocclusions.

The present study aimed to examine whether any pattern of associations could be found between the posture of the head and neck, and the occurrence of malocclusions. The sample comprised 96 children (45 M, 51 F) aged 7-13 years, sequentially admitted for orthodontic treatment of severe malocclusions. Malocclusions were diagnosed clinically and classified into occlusal, spacing, and dentitional anomalies and their subdivisions. Craniovertical, craniocervical, and cervicohorizontal postural variables were recorded from lateral cephalometric radiographs taken with the subject standing with the head in the natural head position (mirror position). A clear pattern of associations between crowding and craniocervical posture was found. Subjects with anterior crowding, i.e. more than 2 mm lack of space in the upper or lower anterior segments of the dental arch, had craniocervical angles that were on average 3-5 degrees larger than subjects without crowding (P < 0.05, P < 0.01). The findings were in agreement with the soft tissue stretching hypothesis, according to which the sagittal development of the dentoalveolar arches is impeded by the increased dorsally-directed soft tissue pressure in subjects with extended craniocervical posture.