The effect of mode of breathing on craniofacial growth—revisited

It has been maintained that because of large adenoids, nasal breathing is obstructed leading to mouth breathing and an ‘adenoid face', characterized by an incompetent lip seal, a narrow upper dental arch, increased anterior face height, a steep mandibular plane angle, and a retrognathic mandible. This development has been explained as occurring by changes in head and tongue position and muscular balance. After adenoidectomy and change in head and tongue position, accelerated mandibular growth and closure of the mandibular plane angle have been reported. Children with obstructive sleep apnoea (OSA) have similar craniofacial characteristics as those with large adenoids and tonsils, and the first treatment of choice of OSA children is removal of adenoids and tonsils. It is probable that some children with an adenoid face would nowadays be diagnosed as having OSA. These children also have abnormal nocturnal growth hormone (GH) secretion and somatic growth impairment, which is normalized following adenotonsillectomy. It is hypothesized that decreased mandibular growth in adenoid face children is due to abnormal secretion of GH and its mediators. After normalization of hormonal status, ramus growth is enhanced by more intensive endochondral bone formation in the condylar cartilage and/or by appositional bone growth in the lower border of the mandible. This would, in part, explain the noted acceleration in the growth of the mandible and alteration in its growth direction, following the change in the mode of breathing after adenotonsillectom

Reliability of growth prediction with hand-wrist radiographs

The aim of this study was to investigate the validity of hand-wrist radiographic analysis in estimating the amount of remaining craniofacial growth. The material compromised cephalograms of 22 males and 27 females with a Class I malocclusion. The median age of the females at the beginning (T1) was 11 years 10 months and of the males 12 years 6 months and at the end (T2) of treatment 14 years 7 months and 15 years 3 months, respectively. Statural height was measured and a lateral cephalogram was obtained for every patient at T1 and T2. A hand-wrist radiograph was taken only at T1. The cephalograms were scanned and analyzed. Relative dimensional growth changes in statural height as well as of the length of the cranial base (N-S), the maxilla (Ptm-A), and the dimensions of the mandible (Co-Gn, Go-Gn, and Co-Gn) from T1 to T2 were determined and statistically compared (Pearson's correlation coefficients) with the growth prediction assessed with the help of hand-wrist radiographs according to Greulich and Pyle. The results showed a highly significant correlation between statural growth increases and growth prediction assessed from the hand-wrist radiographs (females: r = 0.68; males: r = 0.7). Concerning craniofacial structures, the increase in mandibular corpus showed the highest correlation with growth prediction (females: r = 0.21; males: r = 0.52), but this association would not allow a reliable growth prediction. There was no significant correlation between growth increases of the cranial base, the maxilla, the ramus, and the effective length of the mandible and growth prediction assessed with the help of hand-wrist radiographs. As each patient has an individual growth pattern and different craniofacial structures show individual growth potential, it is questionable if quantitative craniofacial growth prediction with the help of hand-wrist radiographs is reliable. However, in an individual case for the assessment of the timing of the growth process, a hand-wrist radiograph can contribute to treatment plannin

Is the use of the cervical vertebrae maturation method justified to determine skeletal age? A comparison of radiation dose of two strategies for skeletal age estimation

The aim of this study was to assess effective doses of a lateral cephalogram radiograph with and without thyroid shield and compare the differences with the radiation dose of a hand-wrist radiograph. Thermoluminescent dosimeters were placed at 19 different sites in the head and neck of a tissue-equivalent human skull (RANDO phantom). Analogue lateral cephalograms with and without thyroid shield (67kV, 250 mA, 10 mAs) and hand-wrist radiographs (40kV, 250 mA, 10 mAs) were obtained. The effective doses were calculated using the 2007 International Commission on Radiological Protection recommendations. The effective dose for conventional lateral cephalogram without a thyroid shield was 5.03 microsieverts (µSv). By applying a thyroid shield to the RANDO phantom, a remarkable dose reduction of 1.73 µSv could be achieved. The effective dose of a conventional hand-wrist radiograph was calculated to be 0.16 µSv. Adding the effective dose of the hand-wrist radiograph to the effective dose of the lateral cephalogram with thyroid shield resulted in a cumulative effective dose of 3.46 µSv. Without thyroid shield, the effective dose of a lateral cephalogram was approximately 1.5-fold increased than the cumulative effective dose of a hand-wrist radiograph and a lateral cephalogram with thyroid shield. Thyroid is an organ that is very sensitive to radiation exposure. Its shielding will significantly reduce the effective dose. An additional hand-wrist radiograph, involving no vulnerable tissues, however, causes very little radiation risk. In accordance with the ALARA (As Low As Reasonably Achievable) principle, if an evaluation of skeletal age is indicated, an additional hand-wrist radiograph seems much more justifiable than removing the thyroid shiel

Abnormal mandibular growth and the condylar cartilage

Deviations in the growth of the mandibular condyle can affect both the functional occlusion and the aesthetic appearance of the face. The reasons for these growth deviations are numerous and often entail complex sequences of malfunction at the cellular level. The aim of this review is to summarize recent progress in the understanding of pathological alterations occurring during childhood and adolescence that affect the temporomandibular joint (TMJ) and, hence, result in disorders of mandibular growth. Pathological conditions taken into account are subdivided into (1) congenital malformations with associated growth disorders, (2) primary growth disorders, and (3) acquired diseases or trauma with associated growth disorders. Among the congenital malformations, hemifacial microsomia (HFM) appears to be the principal syndrome entailing severe growth disturbances, whereas growth abnormalities occurring in conjunction with other craniofacial dysplasias seem far less prominent than could be anticipated based on their oftendisfiguring nature. Hemimandibular hyperplasia and elongation undoubtedly constitute the most obscure conditions that are associated with prominent, often unilateral, abnormalities of condylar, and mandibular growth. Finally, disturbances of mandibular growth as a result of juvenile idiopathic arthritits (JIA) and condylar fractures seem to be direct consequences of inflammatory and/or mechanical damage to the condylar cartilag

Long-term stability of anterior open bite closure corrected by surgical-orthodontic treatment

In adults, superior repositioning of posterior maxilla with or without mandibular surgery has become the treatment method of choice to close anterior open bite. Study aim was to examine the long-term stability of anterior open bite closure by superior repositioning of maxilla or by combining maxillary impaction with mandibular surgery. The sample comprised 24 patients who underwent anterior open bite closure by superior repositioning of maxilla (maxillary group, n = 12, mean age 29.3 years) or by maxillary impaction and mandibular osteotomy (bimaxillary group, n = 12, mean age 30.8 years). Lateral cephalograms were studied prior to surgery (T1), the first post-operative day (T2) and in the long term (T3, maxillary group mean 3.5 years; bimaxillary group mean 2.0 years). Paired and two-sample t-tests were used to assess differences within and between the groups. The vertical incisal bite relations were −2.6 and −2.2 mm at T1; 1.23 and 0.98 mm at T2; and 1.85 and 0.73 mm at T3 in the maxillary and bimaxillary groups. At T3, all subjects had positive overbite in the maxillary group, but open bite recurred in three subjects with bimaxillary surgery. For both groups, the maxilla relapsed vertically. Significant changes in sagittal and vertical positions of the mandible occurred in both groups. In the bimaxillary group, the changes were larger and statistically significant. In general, the maxilla seems to relapse moderately vertically and the mandible both vertically and sagittally, particularly when both jaws were operated on. Overbite seems to be more stable when only the maxilla has been operated o

Cervical vertebrae anomalies in subjects with Class II malocclusion assessed by lateral cephalogram and cone beam computed tomography

A high prevalence of cervical vertebrae anomalies (CVA) has been recently associated with various malocclusions. Our aim was to study the prevalence of CVA on lateral cephalograms in Class II subjects and to compare the findings with those obtained from cone beam computed tomography (CBCT). Standardized cephalograms of 238 Class II patients were analysed for CVA. Cephalogram and CBCT were available for an additional 21 subjects. Cephalometric values were correlated with vertebrae morphology; logistic regressions and intraobserver agreement were evaluated. Inspection of lateral cephalograms could exclude CVA in 90.3 per cent of the subjects, while 9.7 per cent showed potential fusions. No correlations were found between the cephalometric values and potential vertebrae anomalies. In the 21 patients with a CBCT and a lateral cephalogram, the visual assessment of the cephalogram yielded a potential fusion in nine cases. None could be confirmed by CBCT. A low number of potentially fused cervical vertebrae could be detected on lateral cephalograms. The possible fusions did not correlate to any cephalometric values nor could they be confirmed by CBCT, the gold standard for assessing CVA. Visual examination of a cephalogram may result in a false-positive finding and does not allow reliable diagnosis of CV

Long-term changes in pharyngeal airway dimensions following activator-headgear and fixed appliance treatment

The aim of this study was to evaluate changes in the pharyngeal airway in growing children and adolescents and to compare these with a group of children who received activator-headgear Class II treatment. The sample consisted of 64 children (32 males and 32 females), 32 had a combined activator-headgear appliance for at least 9 months (study group) followed by fixed appliance therapy in most patients, while the other half received only minor orthodontic treatment (control group). Lateral cephalograms before treatment (T1, mean age 10.4 years), at the end of active treatment (T2, mean age 14.5 years), and at the long-term follow-up (T3, mean age 22.1 years) were traced and digitized. To reveal the influence of somatic growth, body height measurements were also taken into consideration. A two-sample t-test was applied in order to determine differences between the groups. At T1, the study group had a smaller pharynx length (P = 0.030) and a greater ANB angle (P < 0.001) than the controls. The pharyngeal area and the smallest distance between the tongue and the posterior pharyngeal wall also tended to be smaller in the study group. During treatment (T1-T2), significant growth differences between the two groups were present: the study group had a greater reduction in ANB (P < 0.001) and showed a greater increase in pharyngeal area (P = 0.007), pharyngeal length (P < 0.001) and the smallest distance between the tongue and the posterior pharyngeal wall (P = 0.038). At T2, the values for the study group were similar to those of the control group and remained stable throughout the post-treatment interval (T2-T3). Activator-headgear therapy has the potential to increase pharyngeal airway dimensions, such as the smallest distance between the tongue and the posterior pharyngeal wall or the pharyngeal area. Importantly, this increase seems to be maintained long term, up to 22 years on average in the present study. This benefit may result in a reduced risk of developing long-term impaired respiratory functio

Pharyngeal airway dimensions: a cephalometric, growth-study-based analysis of physiological variations in children aged 6-17

SummaryOBJECTIVE: The aim was to assess pharyngeal airway dimensions and physiological changes based on lateral cephalometric radiographs from healthy untreated children aged 6-17 years. MATERIALS/METHODS: The sample consisted of 880 lateral cephalograms (412 females and 468 males) of the Zurich Craniofacial Growth Study. Statistical analyses on cephalometric measurements of airway dimensions (distances ‘p': shortest distance between soft palate and posterior pharyngeal wall and ‘t': shortest distance between tongue and posterior pharyngeal wall) and craniofacial parameters were performed. To disclose differences between different age groups, a Kruskal-Wallis test was applied. The influence of gender on ‘p' and ‘t' was analysed by a Mann-Whitney U-test for each age group separately. The Spearman correlation was computed in order to investigate associations between craniofacial parameters. Variables associated with ‘p' and ‘t' were chosen for multiple regression model investigation. RESULTS: The results demonstrated high interindividual variations. A slight influence of age on ‘p' (P = 0.034) could be attested (+1.03mm) but not on ‘t' (P = 0.208). With the exception of the 9-year age group, no significant differences between the genders were found. Correlation analysis revealed several statistically significant correlations between ‘t' or ‘p' and antero-posterior cephalometric variables. All correlation coefficients were, however, very low and the adjusted coefficient of determination also revealed the regression model to be very weak. CONCLUSIONS: The high interindividual variations of ‘p' and ‘t' render the use of reference values problematic. Contrary to other craniofacial structures, neither age-related changes nor sexual dimorphism were found for ‘p' and ‘t'. Any associations to antero-posterior cephalometric characteristics seem lo

Mandibular movements in children with deciduous and mixed dentition and in young adults with permanent dentition-the association between movements and occlusal traits

BACKGROUND: Cross-sectional studies of mandibular movements provide data on developmental trends of dentition and support planning of public health services. OBJECTIVE: The aim of this study was to measure mandibular movement capacities in children with deciduous and mixed dentition and in young adults with permanent dentition. The influence of age and gender on mandibular movements and the association between mandibular movements and occlusal traits were analysed. METHOD: The sample consisted of 1172 Estonians: group 1: children with deciduous dentition; group 2: children with mixed dentition; and group 3: young adults with permanent dentition. Maximum opening, mandibular laterotrusion, and protrusion were registered. RESULTS: Age was correlated with mandibular movements. Young adults had statistically significantly larger mandibular movements as compared to children with deciduous and mixed dentition, and children with mixed dentition had larger mandibular movements as compared to children with deciduous dentition. Young adult males had larger mandibular movements than females of the same age. Associations were found between mandibular movement capacities and some occlusal traits. Mandibular movement capacities were smaller in children with crossbite and open bite as compared with children without corresponding occlusal traits. Mandibular movement capacities were larger in children with deep bite and increased overjet as compared with those without corresponding occlusal traits. CONCLUSION: Mandibular movement capacities are age and gender dependent. Maximum mouth opening, mandibular laterotrusion, and protrusion are related, and mandibular movement and some occlusal traits are associated.acceptedVersionPeer reviewe

The inclination of mandibular incisors revisited

Objective: To reassess the inclination of lower incisors and evaluate possible associations with gender, age, symphyseal parameters, and skeletal pattern. Materials and Methods: Twelve hundred and seventy-two (605 females, 667 males) cephalograms of untreated subjects of a craniofacial growth study (age: 8-16 years) were evaluated. Correlations between the angulation of the lower incisors and age, symphyseal distances (height, width, and depth), symphyseal ratios (height-width, height-depth), and skeletal angles (divergence of the jaws and gonial angle) were investigated for all ages separately and for both sexes independently. Results: The inclination of lower incisors increased over age (8 years: girls  =  93.9° [95% CI, 92.3°-95.7°], boys  =  93.3° [95% CI, 91.8°-94.9°]; 16 years: girls  =  96.1° [95% CI, 94.1°-98.2°], boys  =  97.1° [95% CI, 95.6°-98.6°]). Inclination of lower incisors correlated with the divergence of the jaws for all ages significantly or highly significantly, except for boys and girls 9 years of age and girls 11 and 12 years of age, for which only a tendency was observed. Similarly, a strong correlation to gonial angle could be observed. No correlation could be found between the inclination of lower incisors and any symphyseal parameters (absolute measurements and ratios), except for symphyseal depth. Conclusion: Lower incisor inclination is linked to the subject's sex, age, and skeletal pattern. It is not associated with symphyseal dimensions, except symphyseal depth. Factors related to natural inclination of lower incisors should be respected when establishing a treatment plan