Stability of fiducial cephalometric landmarks of growing Class II malocclusion patients: a three-dimensional retrospective study.

OBJECTIVES: To evaluate three-dimensionally (3D) the stability of Nasion (Na), Sella (S), Basion (Ba), Porion (Po), and Orbitale (Or) in different age groups of growing Class II malocclusion patients and, additionally, to assess rotational changes of the S-Na and Ba-Na lines and the Frankfurt Horizontal Plane (FHP). MATERIALS AND METHODS: Cone-beam computed tomography studies of 67 Class II division 1 malocclusion patients, acquired at baseline (T0) and 1 year later (T1), were retrospectively assessed. Anterior cranial fossa was used for volumetric superimposition. Subjects were grouped according to their age at T0: group 1 (G1) (8-10 years), G2 (11-13 years), and G3 (14-17 years). Quantitative assessments of the 3D linear displacements (Euclidean distance) in the position of Na, S, Ba, Po, and Or were performed. Displacement in the X, Y, and Z projections and the rotation of S-Na, Na-Ba, and FHP were also quantified. RESULTS: All cephalometric landmarks showed 3D displacement (P = .001) in the three age groups. Orbitale remained stable in the vertical and sagittal dimension from 8 to 17 years (P > .05). S-Na, Na-Ba, and the FHP showed statistically significant angular rotation (P < .05) in younger patients (G1), while in older individuals (G2 and G3) they were stable (P > .05). CONCLUSIONS: Na, S, Ba, and Po showed vertical and sagittal positional changes relative to the anterior cranial fossa during the growth of Class II individuals. After age 11, S-Na, Na-Ba, and FHP did not show rotation and, thus, are valid parameters for angular cephalometric analysis in Class II growing patients.

Are computed tomography 3D measurements of the upper airways in mouth-breathing children in agreement with the ENT clinical diagnosis of obstruction? / Medidas obtidas por tomografia computadorizada em 3D das vias aéreas superiores em crianças com respiração bucal estão de acordo com o diagnóstico clínico-otorrinolaringológico de obstrução?

Abstract Introduction: Imaging studies have hystorically been used to support the clinical otorhinolaryngological evaluation of the upper respiratory tract for the diagnosis of obstructive causes of oral breathing. Objective: The objective of this study was to compare 3D volumetric measurements of nasal cavity, nasopharynx and oropharynx of obstructed mouth-breathing children with measurements of non-obstructed mouth-breathing children. Methods: This retrospective study included 25 mouth-breathing children aged 5-9 years evaluated by otorhinolaryngological clinical examination, flexible nasoendoscopy and full-head multi-slice computed tomography. Tomographic volumetric measurements and dichotomic otorhinolaryngological diagnosis (obstructed vs. non-obstructed) in three anatomical regions (the nasal cavity, nasopharynx and oropharynx) were compared and correlated. An independent sample t-test was used to assess the association between the 3D measurements of the upper airways and the otorhinolaryngological diagnosis of obstruction in the three anatomical regions. Inter- and intra-observer intraclass correlation coefficients were used to evaluate the reliability of the 3D measurements. Results: The intra-class correlation coefficients ranged from 0.97 to 0.99. An association was found between turbinate hypertrophy and nasal cavity volume reduction (p < 0.05) and between adenoid hyperplasia and nasopharynx volume reduction (p < 0.001). No association was found between palatine tonsil hyperplasia and oropharynx volume reduction. Conclusions: (1) The nasal cavity volume was reduced when hypertrophic turbinates were diagnosed; (2) the nasopharynx was reduced when adenoid hyperplasia was diagnosed; and (3) the oropharynx volume of mouth-breathing children with tonsil hyperplasia was similar to that of non-obstructed mouth-breathing children. The adoption of the actual anatomy of the various compartments of the upper airway is an improvement to the evaluation method.

Resumo Introdução: O exame clínico otorrinolaringológico da via aérea superior tem sido historicamente feito com a ajuda de imagens radiográficas para diagnosticar causas obstrutivas da respiração bucal. Objetivo: O objetivo deste estudo foi comparar as medidas volumétricas em 3D da cavidade nasal, nasofaringe e orofaringe entre crianças com respiração bucal e obstrução respiratória e crianças respiradoras bucais sem obstrução respiratória. Método: Estudo retrospectivo que inclui 25 crianças respiradoras bucais de 5 a 9 anos. As crianças foram avaliadas por exame clínico otorrinolaringológico, nasofibroscopia flexível e tomografia computadorizada multi-slice. Medidas volumétricas obtidas tomograficamente de três regiões anatômicas (cavidade nasal, nasofaringe e orofaringe) foram correlacionadas e comparadas com diagnóstico dicotômico otorrinolaringológico (obstruído vs. não obstruído). Um teste t de amostra independente foi usado para avaliar a associação entre as medidas em 3D das vias aéreas superiores e o diagnóstico otorrinolaringológico de obstrução nas três regiões anatômicas. Os coeficientes de correlação intraclasse inter e intraobservador foram usados para avaliar a confiabilidade das medidas em 3D. Resultados: O coeficiente de correlação intraclasse variou de 0,97 a 0,99. Uma associação foi encontrada entre a hipertrofia de conchas e a redução do volume da cavidade nasal (p < 0,05) e entre a hiperplasia de tonsila faríngea e a redução do volume da nasofaringe (p < 0,001). Não foi encontrada associação entre a hiperplasia da tonsila palatina e a redução do volume da orofaringe. Conclusões: 1) O volume da cavidade nasal estava reduzido nas crianças com diagnóstico de hipertrofia de conchas; 2) O volume da nasofaringe estava reduzido nas crianças com diagnóstico de hiperplasia de tonsila faríngea; e 3) O volume da orofaringe de crianças com respiração bucal e hiperplasia de tonsila palatina foi semelhante ao de crianças respiradoras bucais sem aumento da tonsila palatina. A adoção da mensuração anatômica dos vários compartimentos da via aérea superior complementa o método de avaliação.

Are computed tomography 3D measurements of the upper airways in mouth-breathing children in agreement with the ENT clinical diagnosis of obstruction?

INTRODUCTION: Imaging studies have hystorically been used to support the clinical otorhinolaryngological evaluation of the upper respiratory tract for the diagnosis of obstructive causes of oral breathing. OBJECTIVE: The objective of this study was to compare 3D volumetric measurements of nasal cavity, nasopharynx and oropharynx of obstructed mouth-breathing children with measurements of non-obstructed mouth-breathing children. METHODS: This retrospective study included 25 mouth-breathing children aged 5-9 years evaluated by otorhinolaryngological clinical examination, flexible nasoendoscopy and full-head multi-slice computed tomography. Tomographic volumetric measurements and dichotomic otorhinolaryngological diagnosis (obstructed vs. non-obstructed) in three anatomical regions (the nasal cavity, nasopharynx and oropharynx) were compared and correlated. An independent sample t-test was used to assess the association between the 3D measurements of the upper airways and the otorhinolaryngological diagnosis of obstruction in the three anatomical regions. Inter- and intra-observer intraclass correlation coefficients were used to evaluate the reliability of the 3D measurements. RESULTS: The intra-class correlation coefficients ranged from 0.97 to 0.99. An association was found between turbinate hypertrophy and nasal cavity volume reduction (p<0.05) and between adenoid hyperplasia and nasopharynx volume reduction (p<0.001). No association was found between palatine tonsil hyperplasia and oropharynx volume reduction. CONCLUSIONS: (1) The nasal cavity volume was reduced when hypertrophic turbinates were diagnosed; (2) the nasopharynx was reduced when adenoid hyperplasia was diagnosed; and (3) the oropharynx volume of mouth-breathing children with tonsil hyperplasia was similar to that of non-obstructed mouth-breathing children. The adoption of the actual anatomy of the various compartments of the upper airway is an improvement to the evaluation method.

Three-dimensional assessment of the middle cranial fossa and central skull base following Herbst appliance treatment.

OBJECTIVES:: The purpose of this three-dimensional (3D) study was to assess retrospectively the middle cranial fossa and central skull base of patients treated with the Herbst appliance (HA). MATERIALS AND METHODS:: 3D surface virtual models of 40 Class II, division 1 malocclusion patients were generated from cone-beam computed tomography (CBCT) acquired before treatment (T0) and after 8 months of HA treatment (T1). T0 and T1 3D models were superimposed volumetrically at the anterior cranial fossa. Twenty subjects who had been treated with the Herbst appliance (HAG) were compared to 20 subjects who were not treated orthopedically. The latter group served as a comparison control group (CG). Quantitative assessments of the location and directional changes were made with linear and angular measurements between anatomical landmarks. Qualitative assessments of the spatial behavior of the middle cranial fossa and central skull base relative to the anterior cranial fossa were displayed graphically for visualization with color maps and semitransparent overlays. Non-parametric tests were performed to compare the between the HAG and CG. RESULTS:: Point-to-point linear measurements and skeletal rotation (pitch, roll, and yaw) changes were very small along the observational period and were not significantly different between HAG and CG. Visual analysis of color maps and overlays confirmed that no changes in the cranial base were associated with HA. CONCLUSIONS:: HA therapy did not produce clinically significant changes in the middle cranial fossa and central skull base.

Three-dimensional positional assessment of glenoid fossae and mandibular condyles in patients with Class II subdivision malocclusion.

OBJECTIVES: To test the null hypotheses that the positions of the glenoid fossae and mandibular condyles are identical on the Class I and Class II sides of patients with Class II subdivision malocclusion. MATERIALS AND METHODS: Retrospective three-dimensional (3D) assessments of the positions of the glenoid fossae and mandibular condyles were made in patients with Class II malocclusion. Relative to a fiducial reference at the anterior cranial base, distances from the glenoid fossae and condyles were calculated in pretreatment cone beam computed tomographic scans of 82 patients: 41 with Class II and 41 with Class II subdivision malocclusions. The 3D distances from glenoid fossae to sella turcica in the X (right-left), Y (anterior-posterior), Z (inferior-superior) projections were calculated. RESULTS: Patients with Class II malocclusion displayed a symmetric position of the glenoid fossae and condyles with no statistically significant differences between sides (P > .05), whereas patients with Class II subdivision showed asymmetry in the distance between the glenoid fossae and anterior cranial base or sella turcica (P < .05), with distally and laterally positioned glenoid fossae on the Class II side. (P < .05). Male patients had greater distances between glenoid fossae and anterior cranial fossae (P < .05). The condylar position relative to the glenoid fossae did not differ between the two malocclusion groups nor between males and females (P > .05). CONCLUSIONS: The null hypotheses were rejected. Patients with Class II subdivision malocclusion displayed asymmetrically positioned right- and left-side glenoid fossae, with a distally and laterally positioned Class II side, although the condyles were symmetrically positioned within the glenoid fossae.

Displacement of the Mandibular Condyles Immediately after Herbst Appliance Insertion - 3D Assessment.

OBJECTIVE: To test the following two hypotheses regarding the consequences of Herbst appliance (HA) insertion: 1) a significant clockwise mandibular rotation will occur and 2) the displacement of the condyles will follow the same magnitude of the changes of overjet (OJ) and overbite (OB). METHODS: Virtual 3D surface models of 25 patients were generated from cone-beam computed tomographs taken before treatment and immediately after HA insertion. Scans were registered on the cranial base and were analyzed using point-to-point measurements, color-coded maps, and semitransparent overlays. Statistical tests included correlation and simple regression analysis. RESULTS: Pitch rotation, ranging from -2.2° to 2.2° (mean, 0.2°), was observed in clockwise and counterclockwise directions. Condylar sagittal displacement presented a positive correlation with OJ changes. Each millimeter of OJ correction resulted in an anterior condylar displacement of approximately 0.95 mm. Vertical condylar displacement correlated with OB changes and varied mostly between 2 mm and 4.5 mm. CONCLUSION: Immediately after HA insertion, no significant clockwise mandibular rotation was observed. The condyles were displaced anteriorly and inferiorly. Condylar anterior displacement and OJ correction presented a ratio close to 1:1. The vertical displacement of the condyles did not follow the same magnitude of OB changes.

Do orthodontists recommend Class II treatment according to evidence-based knowledge? / Os ortodontistas recomendam o tratamento das más oclusões de Classe II de acordo com os conceitos científicos atuais?

Introduction: The adequate indications for the timing of treatment for Class II malocclusion are mandatory for the ethical and efficient practice of orthodontics, but clinicians are reluctant to accept new information that contradicts their preferred method of treatment. Objective: The aim of this investigation was to assess the agreement regarding the indications for Class II malocclusion interceptive therapy between a group of international opinion-makers on early treatment and a group of orthodontists and to compare their treatment indications with the current evidence-based knowledge. Material and method: An electronic survey containing photographs of mild, moderate and severe Class II malocclusions in children was sent to two panels of experts. Panel 1 (n=28) was composed of international orthodontists who had authored world-class publications on early orthodontic treatment, and Panel 2 (n=261) was composed of clinical orthodontists. Based on a 5-point Likert-type scale, the orthodontists selected their therapy option for each of the 9 Class II malocclusion cases. Result: The Class II malocclusion treatment recommendations of Panel 2 were significantly different from those offered by Panel 1 with a skew of at least 1 scale point toward earlier treatment. The Class II malocclusion treatment recommendations of the members of Panel 1 members were in accordance with contemporary evidence-based knowledge. Conclusion: Class II malocclusion overtreatment appears to be the tendency among clinical orthodontists but not among orthodontists who are academically involved with early treatment. There is a gap between the scientific knowledge and the practices of orthodontists.

Introdução: A indicação correta da época de tratamento de uma má oclusão de Classe II é essencial para o exercício ético e eficiente da Ortodontia, mas os clínicos são resistentes em aceitar novos conceitos que contradizem seus métodos preferidos de tratamento. Objetivo: Avaliar a concordância na indicação de tratamento interceptor das más oclusões de Classe II entre um grupo de formadores de opinião em nível internacional e um grupo de ortodontistas clínicos, e comparar a indicação de tratamento com os conceitos científicos contemporâneos. Material e método: Um questionário eletrônico composto por fotografias representativas de diversos graus de gravidade no acometimento da má oclusão de Classe II em crianças foi enviado a dois painéis de especialistas. Painel 1 (n=28) foi composto por ortodontistas internacionais autores de artigos científicos em revistas de elevado impacto, e o Painel 2 (n=261) foi composto por ortodontistas clínicos. Baseando-se em uma escala de Likert de 5 pontos, os ortodontistas indicaram suas opções de tratamento para cada um dos 9 casos apresentados. Resultado: As indicações de tratamento do Painel 2 foram estatisticamente diferentes daquelas ofertadas pelo Painel 1, com pelo menos 1 ponto de divergência no sentido de tratamento mais precoce. A indicação de tratamento ortodôntico interceptor do Painel 1 está de acordo com os conceitos científicos atuais. Conclusão: Tratamento muito precoce parece ser a tendência de conduta entre os ortodontistas clínicos, mas não entre os ortodontistas que estão academicamente envolvidos com a interceptação ortodôntica. Existe uma lacuna entre o conhecimento científico e a prática da Ortodontia.

Effective and Efficient Herbst Appliance Therapy for Skeletal Class II Malocclusion Patient with a Low Degree of Collaboration with the Orthodontic Treatment.

The current concept for effective and efficient treatment of skeletal Class II malocclusion prescribes that interceptive approach should be delivered during the pubertal growth stage. However, psychosocial issues and a greater risk of dental trauma are also factors that should be addressed when considering early Class II therapy. This paper reports a case of a patient that sought orthodontic treatment due to aesthetic discomfort with the incisors' protrusion. Two previous treatments failed because patient's collaboration with removable appliances was inadequate. Given his history of no collaboration and because the patient was in the prepubertal stage, it was decided to try a different approach in the third attempt of treatment. Traumatic injury protective devices were used during the prepubertal stage and followed by Herbst appliance and fixed multibrackets therapy during the pubertal stage, resulting in an adequate outcome and long-term stability.