Evaluating interactions of airway changes during growth with orthodontic treatment.

OBJECTIVE: The aim of this study was to longitudinally evaluate changes in the pharyngeal airway volume in adolescents treated with fixed orthodontic appliances compared to matched untreated adolescents and to assess its impact on airflow resistance. MATERIALS AND METHODS: The sample consisted of 16 adolescents (mean start age of 11 years 3 months) who had started and completed treatment at the orthodontic department of the University of Detroit Mercy School of Dental Medicine. This group was compared to a control that consisted of 16 adolescents (mean start age 12 years) who had two CBCTs with no treatment in between for the purpose of regular orthodontic evaluation. Differences in airway volume, length, minimum cross-sectional area, and the average cross-sectional area were calculated. RESULTS: The results indicated that the airway volume increased by 39% and was a statistically significant change (P<0.05). Regarding the influence on airflow resistance, the change in cross sectional area was significant in the group treated with fixed orthodontic appliances (P<0.03). CONCLUSION: Adolescents treated with fixed orthodontic appliances do experience an increase in airway volume, as well as a decrease in airway resistance to airflow compared to that in normal growth.

Relationship between oro and nasopharynx permeability and the direction of facial growth.

AIM: Most scientific literature relates vertical growth to individuals with decreased upper airway permeability. However, we often find subjects with a long face and a normal breathing pattern, most likely caused by other aetiological factors. And, frequently, we also find decreased upper airway permeability with horizontal growth. The aim of the study was to compare the cephalometric measurements of the oro and nasopharynx permeability with the facial growth direction and to identify the most common facial growth direction in individuals with decreased upper airway permeability. MATERIALS AND METHODS: Cephalometric analysis was carried out in 158 pre-adolescent patients at the Orthodontic appointment, using facial profile teleradiographs. Parameters used were Jabarak's ratio and measurement of oro-nasopharynx space. Data collected were submitted to statistical treatment. RESULTS: This study points to the presence of an intermediate growth in individuals with diminished oro and nasopharynx permeability, either simultaneous or separate. The number of individuals with diminished permeability and vertical growth is close to the number of individuals with horizontal growth. CONCLUSIONS: The individuals with diminished permeability of the upper airway present an intermediate growth direction, representing the most frequent type. In the less common growth directions, there is a slight tendency to horizontal facial growth verified in individuals with diminished nasopharynx permeability. Also, a light tendency to vertical facial growth is present when oropharynx permeability is reduced.

Upper airway changes in Pierre Robin sequence from childhood to adulthood.

OBJECTIVES: To investigate pharyngeal airway changes in patients with Pierre Robin sequence (PRS) longitudinally from childhood to adulthood. SETTING AND SAMPLE POPULATION: Cleft Lip and Palate Unit, Clinic of Orthodontics, University of Zurich. Twenty-four patients born between 1970 and 1990 with non-syndromic PRS. MATERIALS AND METHODS: Lateral cephalograms at age 5 (T1), 10 (T2), 15 (T3) and 20 (T4) years were available. Variables describing pharyngeal airway dimensions, soft palate morphology, tongue and hyoid position, skeletal morphology and head posture were assessed. RESULTS: A significant increase in nasopharyngeal depth was found over the entire observation period (T1 10.7 to T4 19.1 mm, p < 0.001), especially between T2 and T3 (change 3.8 mm, p < 0.001), and was mainly due to adenoid recession (r = -0.75, p < 0.001; variation explained by 56%). Increase in velopharyngeal depth mainly took place between T3 and T4 (change 2.3 mm, p < 0.01). It was due to more anterior tongue posture (r = 0.65, p < 0.001; 42.5% of variation explained), in turn allowing the soft palate to take a more vertical position (r = -0.52, p < 0.001). Increase in oropharyngeal depth was associated with head extension and anterior mandibular positioning (36% of variation explained). However, significance was not reached (T1 8.3 to T4 9.8 mm, p > 0.05). CONCLUSIONS: Upper airway dimensions in children with PRS improve with time, except for the oropharyngeal airway. Despite large interindividual variation, the mean remained in the lower reaches of normality described in other studies. Thus, further research should investigate the prevalence of obstructive sleep apnoea in adults with PRS.

Avaliação dos espaços da naso e orofaringe dos quatro aos seis anos de idade / Naso and oropharynx spaces evaluation of four to six years of age

Objetivo: elaborou-se este estudo com o objetivo de avaliar as alterações noespaço das vias aéreas superiores, naso e orofaringe, e observar a existência de dirnorfismosexual. Material e Métodos: por meio de telerradiogralias da cabeça obtidas em normalateral, de 22 crianças (oito do sexo masculino e 14 do feminino), efetuadas aos quatroanos e aos seis anos de idade, estudou-se longitudinalmente as vias aéreas superiores .Mensurou-se cefalometricamente quatro medidas lineares: Pa-Pp e Su-In, para avaliar oespaço da nasofaringe, e Oa-Ope Ma-Mp, para a orofaringe. Resultados: todas as medidasavaliadas apresentaram aumento entre as idades de quatro e seis anos. Para as criançasdo sexo masculino encontrou-se um aumento de 2,03 mm para Pe-Pp, 1,11 mm para Su-In,0,52 mm para Oa-Op e 1,44 mm para Ma-Mp. As crianças do sexo feminino apresentaramaumentos de 3,18 mm para Pa-Pp, 0,62 mm para Su-In, 0,79 mm para Oa-Op e 0,55 mmpara Ma-Mp. Conclusão: o teste t Student indicou que somente a medida Pa-Pp, para ascrianças do sexo feminino, apresentou aumento estatisticamente signilicante.

Aim: the aim of this study was to evaluate the alterations of the naso andoropharynx spaces and the sexual dimorphism. Material and Methods: this study evaluatedthe development of the upper airways of 22 children, eight male and 14 female, throughtheir cephalometric radiographs at four and six years of age. Four linear measurements wereassessed: Pa-Pp and Su-In to evaluate of the nasopharynx space, Oa-Opand Ma-Mp for theoropharynx. Results: ali measurements demonstrated increase between the ages of fourand six years. Boys demonstrated increase of 2.03 mm for Pa-Pp and 1.11 mm for Su-In,0.52 mm for Oa-Opand 1.44 mm for Ma-Mp. The girls showed an increase of 3.18 mm forPa-Pp, 0.62 mm for Su-In, 0.79 mm for Oa-Op and 0.55 mm for Ma-Mp. Conclusion: thestudent's "t" test showed that only the Pa-Pp revealed a statistically signiticant increase,exclusively in girls.

Oropharyngeal airway dimensions after treatment with functional appliances in class II retrognathic children.

Class II skeletal malocclusion and respiratory disorders owing to the obstruction of the upper airway at early growth stages have been correlated. The retro/micrognathism can be treated with functional appliances. However, the effects of an early functional orthopedic treatment on the airway dimensions have not been evaluated before the growth peak. Therefore, the objective of this study was to evaluate the changes in the airway dimensions of class II retrognathic children who received treatment with either Klammt or Bionator on a pre-pubertal stage. The sample consisted of 50 lateral cephalograms of class II retrognathic patients in a pre-puberal stage, before and after the use of a Klammt or Bionator II treatment for 1 year. The data were evaluated by Student's t-test or Mann-Whitney test, and significance was set at 5% (P < 0·05). When the measurements before and after treatment were compared, a statistically significant increase in the airway dimensions was found at the space where the adenoid tissue was located. The only airway dimensions that increased after treatment with functional appliances were the ones located at the nasopharynx. The adenoid tissue is still in the peak of growing at the ages of the subjects included in this study. However, the measurements along the nasopharynx increased when compared with the initial ones. Still, similar retrospective and prospective studies are needed at older stages.

Developmental sexual dimorphism of the oral and pharyngeal portions of the vocal tract: an imaging study.

PURPOSE: The anatomic origin for prepubertal vowel acoustic differences between male and female subjects remains unknown. The purpose of this study is to examine developmental sex differences in vocal tract (VT) length and its oral and pharyngeal portions. METHOD: Nine VT variables were measured from 605 imaging studies (magnetic resonance imaging and computed tomography) of subjects between birth and age 19 years. Given sex differences in growth rate (Vorperian et al., 2009), assessment of sex differences was done through use of a localized comparison window of 60 months. Analysis entailed applying this comparison window first to 4 discrete age cohorts, followed by a progressive assessment in which this comparison window was moved in 1-month increments from birth across all ages. RESULTS: Findings document significant postpubertal sex differences in both the oral and pharyngeal portions of the VT. They also document periods of significant prepubertal sex differences in the oral region first, followed by segments in the pharyngeal region. CONCLUSIONS: Assessment of developmental sex differences using localized age ranges is effective in unveiling sex differences that growth rate differences may conceal. Findings on the presence of prepubertal sex differences in the oral region of the VT may clarify, in part, the anatomic basis of documented prepubertal acoustic differences.

Anatomic development of the oral and pharyngeal portions of the vocal tract: an imaging study.

The growth of the vocal tract (VT) is known to be non-uniform insofar as there are regional differences in anatomic maturation. This study presents quantitative anatomic data on the growth of the oral and pharyngeal portions of the VT from 605 imaging studies for individuals between birth and 19 years. The oral (horizontal) portion of the VT was segmented into lip-thickness, anterior-cavity-length, oropharyngeal-width, and VT-oral, and the pharyngeal (vertical) portion of the VT into posterior-cavity-length, and nasopharyngeal-length. The data were analyzed to determine growth trend, growth rate, and growth type (neural or somatic). Findings indicate differences in the growth trend of segments/variables analyzed, with significant sex differences for all variables except anterior-cavity-length. While the growth trend of some variables displays prepubertal sex differences at specific age ranges, the importance of such localized differences appears to be masked by overall growth rate differences between males and females. Finally, assessment of growth curve type indicates that most VT structures follow a combined/hybrid (somatic and neural) growth curve with structures in the vertical plane having a predominantly somatic growth pattern. These data on the non-uniform growth of the vocal tract reveal anatomic differences that contribute to documented acoustic differences in prepubertal speech production.

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 function.

Avaliação cefalométrica do espaço orofaríngeo em pacientes com deglutição atípica / Cephalometric evaluation of the oropharyngeal space in cases of atypical swallowing

Objetivo: Avaliar o espaço livre orofaríngeo de indivíduos com deglutição atípica e comparar os valores encontrados com aqueles obtidos na ausência de hábitos bucais deletérios, para tentar estabelecer índices cefalométricos capazes de prever a ocorrência deste hábito. Metodologia: Foram utilizadas as radiografias cefalométricas laterais de 105 indivíduos que apresentavam deglutição atípica, divididas em três faixas etárias. A partir das radiografias foram feitos traçados, sobre os quais foram realizadas medições. Resultados: Verificou-se que a profundidade da orofaringe aumenta entre 6 e 23 anos de idade, não havendo diferenças estatisticamente significantes entre os gêneros masculino e feminino. Não foram encontradas diferenças significantes entre os pacientes portadores de deglutição atípica e aqueles com características de normalidade, nas três faixas etárias estudadas. Conclusão: Não foi possível estabelecer índices cefalométricos capazes de prever a ocorrência de deglutição atípica, associada com interposição lingual, pois os indivíduos estudados foram capazes de manter um posicionamento normal da língua dentro da cavidade bucal quando em repouso.

Purpose: To evaluate the free oropharyngeal airway space in subjects with atypical swallowing and compare the findings with those obtained from normal patients aiming to establish a cephalometric index able to predict atypical swallowing. Methods: Lateral cephalometric radiographs were obtained from 105 subjects with atypical swallowing. Radiographs were divided into three age groups for cephalometric tracing and analysis. Results: Oropharyngeal depth increased between 6 and 23 years-old, and there was no significant difference between males and females. No significant differences of oropharyngeal data were found between patients with normal or atypical deglutition for the three age groups. Conclusion: It was not possible to establish a cephalometric index to predict atypical swallowing associated with tongue interposition because the study subjects were able to maintain their tongues in a normal position inside the oral cavity during rest.

Development of the orohypopharyngeal cavity in normal infants and young children.

OBJECTIVE: To study the growth of the oropharynx and hypopharynx in infants and young children by measuring the lengths of the segments between nasopharyngeal valve and tongue base, tongue base and arytenoids, and arytenoids and upper esophageal sphincter. These measurements will be used as references for developing manofluoroscopy to study deglutition in infants and young children. PATIENTS AND METHODS: Twenty-three children (14 boys, 9 girls) between birth and 4 years of age were prospectively studied. All children had near normal growth parameters and were free of medical illnesses or other major medical conditions that are known to influence the pharyngeal cavity. Lateral videofluoroscopy was used to assess the pharyngeal structures during breathing. All images were digitally recorded and analyzed using a computer program designed specifically for this study. RESULTS AND CONCLUSIONS: Statistically significant correlations were found between the age or height of the patient and the distance from velopharyngeal valve to tongue base and the distance from tongue base to arytenoids, showing a linear increase of the length of the oro- and hypopharynx with age and patient height. There was no significant difference in the pharyngeal distances between boys and girls. On the basis of these results, a linear regression comparison could be established to define the length of each pharyngeal segment for any age until 4 years and for the 50th percentile of height.

Long-term effect of pharyngeal flap surgery on craniofacial and nasopharyngeal morphology in patients with cleft palate.

The craniofacial morphology of 48 consecutive adult males with isolated cleft palate was studied by means of lateral cephalograms at the mean age of 18.8 years. Twelve of the patients had received pharyngeal flap surgery between 4 and 12 years of age (mean age 6 years) to improve speech. No significant differences were noticed in craniofacial cephalometric relations between the patients who had not had velopharyngeal flap surgery (VPF-) and those who had (VPF+), although the latter showed a tendency toward a more vertical growth direction. In the pharynx, the VPF+ group showed larger sagittal depths of nasopharyngeal airway but smaller depths of oropharyngeal airway. The differences were significant at the levels of the upper nasopharynx and lower oropharynx. According to the hospital records, none of the patients demonstrated persistent airway obstruction. Cephalometry may be useful in evaluating the changes in pharyngeal airway dimensions that may be related to velopharyngeal flap surgery.

Magnetic resonance imaging procedures to study the concurrent anatomic development of vocal tract structures: preliminary results.

The vocal tract structures undergo drastic anatomic restructuring during the course of development from infancy to adulthood. This study demonstrates the feasibility of using MRI to examine the growth processes of the vocal tract. This method affords precise and detailed visualization of the soft tissues in the oro-pharyngeal region, while also providing images of related bony and cartilaginous structures. Information on anatomic restructuring contributes to the understanding of how speech emerges and develops, and it also establishes normative information that can be used in the assessment of developmental anomalies. This paper describes the method used to measure and examine the concurrent anatomic development of the various vocal tract structures during early childhood. Preliminary results from two pediatric subjects indicate that there is synchrony of growth in the different structures-both soft and hard tissues-, and that such synchronous growth appears to persist during periods of growth spurts.

Cephalometric changes in adult pharyngeal morphology.

This cephalometric study investigated morphological changes occurring in the pharynx between early and middle adult life. A sample of 16 young adults (mean age 20.2 years) had cephalometric films taken and repeated after an interval of 32 years. Changes in pharyngeal skeletal size, pharyngeal soft tissue thickness, pharyngeal airway depth, and soft palate dimensions were examined, in addition to standard craniofacial measurements. The results showed increases in maxillary prominence, and upper and lower anterior face height. The nasopharyngeal skeletal dimensions were unchanged over the 32-year interval, while the anteroposterior depth of the nasopharyngeal lumen increased as a result of a reduction in thickness of the posterior nasopharyngeal wall. In the oropharynx, the depth of the airway decreased with age, and the soft palate became longer and thicker. The findings indicate that pharyngeal morphology is not immutably established during childhood and adolescence, but changes throughout adult life. The tendency towards a longer and thicker soft palate, and narrower oropharynx during adulthood is discussed in relation to their possible role in explaining the increased prevalence of obstructive sleep apnoea and related disorders in later life.

Oropharyngeal airway dimensions and functional-orthopedic treatment in skeletal Class II cases.

Mandibular deficiency may be a factor in reduced oropharyngeal airway (OAW) dimensions and related impaired respiratory function. The purpose of this study was to evaluate the use of functional-orthopedic devices in increasing OAW dimensions in children with Class II skeletal patterns (ANB > 4) and clinically deficient mandibles. Comparisons were made between two groups, one comprising 26 treated patients and the other comprising 15 controls. Student's t-tests, paired t-tests, discriminant analyses, and Pearson's r-correlation coefficients were performed to evaluate group differences and to search for characteristics that might suggest which patients would be better candidates for significant increase in OAW dimensions. Compared with controls, OAW dimensions increased significantly in treated patients, especially those with sagittally smaller and more retrognathic maxillomandibular complexes and smaller OAW dimensions.

Soft tissue growth of the oropharynx.

The purpose of this study was to describe the pattern of bony and soft tissue growth of the oropharynx in a sample of healthy, orthodontically untreated children. The sample consisted of 16 males and 16 females with lateral cephalograms at 6, 9, 12, 15, and 18 years of age, for a total of 160 lateral cephalometric radiographs. All subjects were enrolled in the Broadbent Bolton Study and their radiographs were used to produce the Bolton Standard Templates. Each radiograph was traced by hand and the tracings were paired and averaged to create a standard template for pharyngeal tissues at each age. In addition, all 160 tracings were digitized and means and standard deviations were calculated for 29 hard and 7 soft tissue measurements. Four linear (Ar-H,S-H,Go-H, Gn-H) and three angular (N-S-H, SN-ArH,GoGn-H) measurements demonstrated that the hyoid bone descends and moves slightly anteriorly up to age 18. The soft palate (PNS-P) increased 1 mm in length and 0.5 mm in thickness every 3 years after age 9. The distance between the anterior border of the atlas (ATA) and PNS did not change after age 12, while two soft tissue measurements (PNS-pharyngeal wall [PhW2] and posterior soft palate to pharyngeal wall [psp-PhW3]) increased. In general, two periods of accelerated change (6-9 years and 12-15 years) and two periods of quiescence (9-12 years and 15-18 years) were identified for the pharyngeal soft tissues. Further studies are needed to determine in soft tissues in the oropharynx continue to change after age 18.

Growth of the pharynx and its physiologic implications.

The bony nasopharynx increases its capacity predominantly by means of vertical development. Analogous to the facial structures is an expression of some somatotopic features that give rise to a higher and more shallow pharyngeal dimension in the dolichocephalic growth pattern. The nasopharynx's ultimate patency, however, depends on the growth and relative size of the soft tissues that line the skeletal boundaries. A decreased patency of the oropharyngeal airway can induce some postural adaptations, which secure a constant sagittal dimension at that level. However, at a certain critical point, purely nasal respiration will be turned into an oronasal breathing pattern, which in turn will elicit more compensatory mechanisms. This muscle recruitment is a possible cause of a deviant vertical craniofacial growth pattern.