How obesity affects nasal function in obstructive sleep apnea: anatomic and volumetric parameters / Como a obesidade afeta a função nasal na apneia obstrutiva do sono: parâmetros anatômicos e volumétricos,

Abstract Introduction Obstructive sleep apnea is a consequence of upper airway collapse. Any obstructive sector in the upper airway can contribute to pharyngeal collapse. Obesity and obesity-related disorders play an important role in obstructive sleep apnea and its relationship with increased upper airway resistance. Objective This study was designed to evaluate the relationship between obesity and properties of the nasal cavity in patients with obstructive sleep apnea. Methods The study was conducted retrospectively by review of medical records of adult patients. The nasal obstruction symptom evaluation, NOSE instrument, was used to measure nasal obstruction. Sleep breathing disorders were evaluated by polysomnography exams. Nasal volume was obtained by computed tomography scans and volumetric reconstruction of nasal airway. Nasal anatomic alterations were assessed by nasal endoscopy. Results Analysis of 83 patient records, among whom 54 were male and 29 females, found the mean body mass index of 28.69 kg/m2. Obese and non-obese groups were determined by using cut-off 30 kg/m2. In the comparison between groups, the obese group had a positive and significant correlation with apnea/hypopnea index (p= 0.02), NOSE instrument (p= 0.033) and inferior turbinate hypertrophy (p= 0.036), with odds ratio 1.983 (95% IC 1.048 − 3.753). nasal septum deviation (p= 0.126) and nasal airway volume evaluation (p= 0.177) showed no significant results. Conclusion Obesity was significantly correlated with subjective nasal obstruction, NOSE scale, and inferior turbinate hypertrophy in patients with obstructive sleep apnea. There was no correlation with the nasal volume evaluation. Level of Evidence 3b - Individual case-control study.

Resumo Introdução A apneia obstrutiva do sono é consequência do colapso das vias aéreas superiores Qualquer região de obstrução nas vias aéreas superiores pode contribuir para o colapso da faringe. A obesidade e os distúrbios relacionados à obesidade desempenham um papel importante na apneia obstrutiva do sono e sua relação com o aumento da resistência das vias aéreas superiores. Objetivo Avaliar a relação entre a obesidade e as propriedades da cavidade nasal em pacientes com apneia obstrutiva do sono. Método O estudo foi feito retrospectivamente através da revisão de prontuários médicos de pacientes adultos. O instrumento de avaliação NOSE, do inglês nasal obstruction symptom evaluation, foi usado para avaliar a obstrução nasal. Os distúrbios respiratórios do sono foram avaliados através de exames polissonográficos. O volume nasal foi obtido por tomografia computadorizada e a reconstrução volumétrica das vias aéreas nasais. As alterações anatômicas nasais foram avaliadas por endoscopia nasal. Resultados A análise dos prontuários de 83 pacientes, entre os quais 54 eram do sexo masculino e 29 do feminino, encontrou um índice de massa corporal médio de 28,69 kg/m2. Os grupos obeso e não obeso foram determinados com o ponto de corte de 30 kg/m2. Na comparação entre os grupos, o grupo obeso apresentou correlação positiva e significante com o índice de apneia/hipopneia (p = 0,02), instrumento NOSE (p = 0,033) e hipertrofia da concha inferior (p = 0,036), com uma odds ratio de 1,983 (IC95%: 1,048 a 3,753). A avaliação do desvio do septo nasal (p = 0,126) e do volume das vias aéreas nasais (p = 0,177) não mostrou resultados significantes. Conclusão A obesidade correlacionou-se significantemente com a obstrução nasal subjetiva pela escala NOSE e hipertrofia de concha inferior em pacientes com apneia obstrutiva do sono. Não houve correlação com a avaliação do volume nasal. Nível de evidência 3b. Estudo de caso-controle individual.

How obesity affects nasal function in obstructive sleep apnea: anatomic and volumetric parameters.

INTRODUCTION: Obstructive sleep apnea is a consequence of upper airway collapse. Any obstructive sector in the upper airway can contribute to pharyngeal collapse. Obesity and obesity-related disorders play an important role in obstructive sleep apnea and its relationship with increased upper airway resistance. OBJECTIVE: This study was designed to evaluate the relationship between obesity and properties of the nasal cavity in patients with obstructive sleep apnea. METHODS: The study was conducted retrospectively by review of medical records of adult patients. The nasal obstruction symptom evaluation, NOSE instrument, was used to measure nasal obstruction. Sleep breathing disorders were evaluated by polysomnography exams. Nasal volume was obtained by computed tomography scans and volumetric reconstruction of nasal airway. Nasal anatomic alterations were assessed by nasal endoscopy. RESULTS: Analysis of 83 patient records, among whom 54 were male and 29 females, found the mean body mass index of 28.69 kg/m2. Obese and non-obese groups were determined by using cut-off 30 kg/m2. In the comparison between groups, the obese group had a positive and significant correlation with apnea/hypopnea index (p = 0.02), NOSE instrument (p = 0.033) and inferior turbinate hypertrophy (p = 0.036), with odds ratio 1.983 (95% IC 1.048 - 3.753). nasal septum deviation (p = 0.126) and nasal airway volume evaluation (p = 0.177) showed no significant results. CONCLUSION: Obesity was significantly correlated with subjective nasal obstruction, NOSE scale, and inferior turbinate hypertrophy in patients with obstructive sleep apnea. There was no correlation with the nasal volume evaluation. LEVEL OF EVIDENCE: 3b - Individual case-control study.

A systematic review of penile prosthesis infection and meta-analysis of diabetes mellitus role.

BACKGROUND: Infection is the most feared complication of a penile prosthesis. Diabetes mellitus (DM) is widely known to increase the risk of several infections, but its role in the penile prosthesis is still controversial. This systematic review aims to show the contemporary scenario of penile prosthesis infection and present a meta-analysis about DM contribution to penile prosthesis infection. METHODS: The review was performed with no language or time limitation, including ten databases. The included articles were about the male population who received a penile prosthesis with no model restriction, with a minimum follow up of 1 year, and outcomes adequately reported. RESULTS: The mean infection incidence of penile prosthesis ranged from 0.33 to 11.4%. In early 2000, the general incidence of infection was 3 to 5%, then, the introduction of coated materials decreased it to 0.3 to 2.7%. The meta-analysis showed that diabetes mellitus is related to an increased risk of penile prosthesis infection with an odds ratio of 1.53 (95% CI 1.15-2.04). CONCLUSIONS: Penile prosthesis infection decreased in the last decades but remains a significant cause of reoperation, and it is related to lower prosthesis survival. Meta-analysis concludes that diabetes mellitus is related to a higher risk of penile prosthesis infection.

Resorbable Versus Titanium Fixation of Le Fort I Osteotomy.

Resorbable and titanium systems have been used in maxillary fixation. The aim of this review was to evaluate stability and morbidity of Le Fort I osteotomy by comparing both systems. It was performed in 11 databases, and reported according to preferred reporting items for systematic reviews and meta-analysis. Randomized and nonrandomized clinical trials, and retrospective comparative studies with patients who underwent nonsegmented Le Fort I osteotomy were included. Eleven articles were selected, with a total of 262 patients treated with resorbable and 252 with titanium fixation. The meta-analysis showed that when measured at point A, horizontal stability was 0.06 mm (95% confidence interval [CI] -0.19, 0.30), vertical stability for impaction was -0.43 mm (95% CI -0.94, 0.07), and for inferior repositioning was -1.29 mm (95% CI -2.62, 0.04). Morbidity was similar in the groups. Regarding infection, resorbable presented an absolute risk (AR) = 0.032, and titanium an AR = 0.025 (P = 1.0). For soft tissue reaction, an AR = 0.120 was shown for resorbable, and an AR = 0.132 for titanium (P = 0.85). Removal of fixation showed an AR = 0.024 for resorbable, and an AR = 0.025 for titanium (P = 1.0). Based on these results, resorbable and metal fixation systems seem to be equivalent with respect to stability and morbidity. This review was limited by the quality of the studies. Future studies should address these quality limitations to improve comparison between these 2 fixation approaches.

Resorbable versus titanium fixation of Le Fort I osteotomy

Resorbable and titanium systems have been used in maxillary fixation. The aim of this review was to evaluate stability and morbidity of Le Fort I osteotomy by comparing both systems. It was performed in 11 databases, and reported according to preferred reporting items for systematic reviews and meta-analysis. Randomized and nonrandomized clinical trials, and retrospective comparative studies with patients who underwent nonsegmented Le Fort I osteotomy were included. Eleven articles were selected, with a total of 262 patients treated with resorbable and 252 with titanium fixation. The meta-analysis showed that when measured at point A, horizontal stability was 0.06 mm (95% confidence interval [CI] −0.19, 0.30), vertical stability for impaction was −0.43 mm (95% CI −0.94, 0.07), and for inferior repositioning was −1.29 mm (95% CI −2.62, 0.04). Morbidity was similar in the groups. Regarding infection, resorbable presented an absolute risk (AR) = 0.032, and titanium an AR = 0.025 (P = 1.0). For soft tissue reaction, an AR = 0.120 was shown for resorbable, and an AR = 0.132 for titanium (P = 0.85). Removal of fixation showed an AR = 0.024 for resorbable, and an AR = 0.025 for titanium (P = 1.0). Based on these results, resorbable and metal fixation systems seem to be equivalent with respect to stability and morbidity. This review was limited by the quality of the studies. Future studies should address these quality limitations to improve comparison between these 2 fixation approaches.

Cost-effectiveness of implant-supported dental prosthesis compared to conventional dental prosthesis.

OBJECTIVE: To conduct a cost-effectiveness analysis of alternatives for rehabilitation treatment of mandibular edentulism in the context of the Brazilian Unified Health System (implant-supported total dental prosthesis versus conventional total dental prosthesis). METHODS: A Markov model was developed to capture long-term clinical and economic outcomes. The model's population was comprised of a hypothetical cohort of 1,000,000 patients, aged 55 years, with total mandibular edentulism and without medical contraindications for performing surgical procedures. The adopted analysis perspective was that of the Brazilian Unified Health System. Based on the proposed model, we calculated cost - in BRL, and effectiveness - measured by quality-adjusted prosthesis year (QAPY). The time horizon of the analysis was 20 years. RESULTS: Considering a 5% discount in costs and effects, the incremental cost-effectiveness ratio of implant-supported total dental prostheses compared to conventional total dental prosthesis (BRL 464.22/QAPY) was lower than the willingness to pay threshold adopted in the model (BRL 3,050.00/QAPY). CONCLUSIONS: The results of this economic analysis showed that the rehabilitation of mandibular edentulous patients by implant-supported total prosthesis is very cost-effective when compared to conventional complete prosthesis, considering the cost-effectiveness limits employed.

Cost-effectiveness of implant-supported dental prosthesis compared to conventional dental prosthesis

OBJECTIVE: To conduct a cost-effectiveness analysis of alternatives for rehabilitation treatment of mandibular edentulism in the context of the Brazilian Unified Health System (implantsupported total dental prosthesis versus conventional total dental prosthesis). METHODS: A Markov model was developed to capture long-term clinical and economic outcomes. The model’s population was comprised of a hypothetical cohort of 1,000,000 patients, aged 55 years, with total mandibular edentulism and without medical contraindications for performing surgical procedures. The adopted analysis perspective was that of the Brazilian Unified Health System. Based on the proposed model, we calculated cost – in BRL, and effectiveness – measured by quality-adjusted prosthesis year (QAPY). The time horizon of the analysis was 20 years. RESULTS: Considering a 5% discount in costs and effects, the incremental cost-effectiveness ratio of implant-supported total dental prostheses compared to conventional total dental prosthesis (BRL 464.22/QAPY) was lower than the willingness to pay threshold adopted in the model (BRL 3,050.00/QAPY). CONCLUSIONS: The results of this economic analysis showed that the rehabilitation of mandibular edentulous patients by implant-supported total prosthesis is very cost-effective when compared to conventional complete prosthesis, considering the cost-effectiveness limits employed.

Custo-efetividade da prótese implanto-suportada comparada à prótese total convencional

OBJETIVO Realizar uma análise de custo-efetividade de alternativas para o tratamento de reabilitação do edentulismo mandibular no contexto do Sistema Único de Saúde (prótese total total suportada por implante versus prótese total total convencional). MÉTODOS Um modelo de Markov foi desenvolvido para capturar resultados clínicos e econômicos a longo prazo. A população do modelo foi composta por uma coorte hipotética de 1.000.000 de pacientes, com 55 anos de idade, com edentulismo mandibular total e sem contraindicações médicas para a realização de procedimentos cirúrgicos. A perspectiva de análise adotada foi a do Sistema Único de Saúde. Com base no modelo proposto, calculamos o custo - em BRL e a eficácia - medidos pelo ano da prótese ajustada à qualidade (QAPY). O horizonte temporal da análise foi de 20 anos. RESULTADOS Considerando um desconto de 5% nos custos e efeitos, a taxa de custo-efetividade incremental das próteses totais totais suportadas por implantes, em comparação com a prótese total total convencional (BRL 464,22 / QAPY), foi inferior ao limiar de disposição a pagar adotado no modelo (BRL 3.050,00 / QAPY). CONCLUSÕES Os resultados dessa análise econômica mostraram que a reabilitação de pacientes desdentados mandibulares por prótese total suportada por implante é muito rentável quando comparada à prótese total convencional, considerando os limites de custo-efetividade empregados.

Cost-effectiveness of implant-supported dental prosthesis compared to conventional dental prosthesis / Custo-efetividade da prótese implanto-suportada comparada à prótese total convencional

ABSTRACT OBJECTIVE To conduct a cost-effectiveness analysis of alternatives for rehabilitation treatment of mandibular edentulism in the context of the Brazilian Unified Health System (implant-supported total dental prosthesis versus conventional total dental prosthesis). METHODS A Markov model was developed to capture long-term clinical and economic outcomes. The model's population was comprised of a hypothetical cohort of 1,000,000 patients, aged 55 years, with total mandibular edentulism and without medical contraindications for performing surgical procedures. The adopted analysis perspective was that of the Brazilian Unified Health System. Based on the proposed model, we calculated cost - in BRL, and effectiveness - measured by quality-adjusted prosthesis year (QAPY). The time horizon of the analysis was 20 years. RESULTS Considering a 5% discount in costs and effects, the incremental cost-effectiveness ratio of implant-supported total dental prostheses compared to conventional total dental prosthesis (BRL 464.22/QAPY) was lower than the willingness to pay threshold adopted in the model (BRL 3,050.00/QAPY). CONCLUSIONS The results of this economic analysis showed that the rehabilitation of mandibular edentulous patients by implant-supported total prosthesis is very cost-effective when compared to conventional complete prosthesis, considering the cost-effectiveness limits employed.

RESUMO OBJETIVO Conduzir uma análise de custo-efetividade das alternativas para tratamento reabilitador do edentulismo mandibular no contexto do Sistema Único de Saúde (prótese total implanto-suportada e prótese total convencional). MÉTODOS Foi desenvolvido um modelo de Markov para captar os resultados clínicos e econômicos de longo prazo. A população do modelo consistiu em uma coorte hipotética de 1.000.000 pacientes, com 55 anos, desdentados totais mandibulares e sem contraindicações médicas para a realização de procedimentos cirúrgicos. A perspectiva de análise adotada foi a do Sistema Único de Saúde. Com base no modelo proposto, calculamos o custo (em reais) e a efetividade, medida pelo ano de prótese ajustado à qualidade (QAPY). O horizonte temporal da análise foi de 20 anos. RESULTADOS Considerando o desconto de 5% nos custos e efeitos, a razão de custo-efetividade incremental da prótese total implanto-suportada em relação à prótese total convencional (R$ 464,22/QAPY) foi menor que o limiar de disposição a pagar adotado no modelo (R$ 3.050,00/QAPY). CONCLUSÕES Os resultados desta análise econômica mostraram que a reabilitação de edêntulos mandibulares por meio da prótese total implanto-suportada é muito custo-efetiva em comparação à prótese total convencional, de acordo com os limites de custo-efetividade empregados.

Cone-Beam Computed Tomography-Based Three-Dimensional McNamara Cephalometric Analysis.

This article introduces a method that extends the McNamara cephalometric analysis to produce 3-dimensional (3D) measurement values from cone-beam computed tomography images. In the extended method, the cephalometric landmarks are represented by 3D points; the bilateral cephalometric landmarks are identified on both sides of the skull; the cephalometric lines, with the exception of the facial axis, are represented by 3D lines; the cephalometric planes, with the exception of the facial plane, are represented by planes; the effective mandibular length, the effective midfacial length, and the lower anterior facial height are measured as 3D point-to-point distances; the nasion perpendicular to point A, the pogonion to nasion perpendicular, the upper incisor to point A vertical, and the lower incisor to point A-pogonion line are measured each as components of a vector; the facial axis angle is measured as a line-to-plane angle; and the mandibular plane angle is measured as a plane-to-plane angle. As a result, the method provides real effective lengths of the maxilla and mandible on both sides of the skull; real height of the lower anterior face; directed distances from the point A to the nasion perpendicular, from the pogonion to the nasion perpendicular, from the left and right upper incisor to the point A vertical, and from the left and right lower incisor to the point A-pogonion line for both the lateral and posteroanterior views of the skull; and real angles of the facial axis and the mandibular plane. Additionality, the method enables the identification of craniofacial asymmetries.

Volumetric evaluation of pharyngeal segments in obstructive sleep apnea patients, / Avaliação volumétrica de segmentos faríngeos em pacientes com apneia obstrutivado sono,

Abstract Introduction Obstructive sleep apnea occurs by recurrent collapse of the upper airway during sleep, resulting in total (apnea) or partial (hypopnea) reduction of the airflow and has intimate relation with changes in the upper airway. Cone Beam CT allows the analysis of the upper airway and its volume by three-dimensional reconstruction. Objective To evaluate a possible correlation between the volume of the upper airway and the severity of the obstructive sleep apnea. Methods A retrospective study was performed reviewing polysomnographic data and Cone Beam CT records of 29 patients (13 males and 16 females). The correlation between the volume of the nasopharynx, the oropharynx and the total superior pharynx with the AHI was assessed by Pearson's rank correlation coefficient. Results The obstructive sleep apnea severity division was: ten patients had severe, 7 had moderate, 6 had mild and 6 of them were healthy. The correlation between the nasopharynx, the oropharynx and the total superior pharynx volumes and the Apnea-Hypopnea-Index was respectively: −0.415 (p = 0.025), 0.186 (p = 0.334) and −0329 (p = 0.089). The Spearman's rank controlled by the Body Mass Index, the age and the gender was: −0.206 (p = 0.304), −0.155 (p = 0.439) and 0.242 (p = 0.284). Conclusion There is no correlation between the volume of the airway and the obstructive sleep apnea, assessed by Apnea-Hypopnea-Index and controlled by the Body Mass Index, the age and the gender. The volume of the upper airways as an isolated parameter did not correlate to the severity of the obstructive sleep apnea syndrome, and should be evaluated together with other factors.

Resumo Introdução A Apneia Obstrutiva do Sono ocorre por colapso recorrente das vias aéreas superiores durante o sono, resultando em redução total (apneia) ou parcial (hipopneia) do fluxo aéreo, tendo relação estreita com alterações nas vias aéreas superiores. A TC de feixe cônico permite a análise da via aérea superior e seu volume através da reconstrução tridimensional. Objetivo Avaliar uma possível correlação entre o volume da via aérea superior e a gravidade da apneia obstrutiva do sono. Método Realizou-se um estudo retrospectivo, com revisão de dados polissonográficos e registros de TC de feixe cônico de 29 pacientes (13 do sexo masculino e 16 do sexo feminino). A correlação entre o volume total da nasofaringe, a orofaringe e a faringe superior com o IAH (Índice de Apneia-Hipopneia) foi avaliada pelo coeficiente de correlação de Pearson. Resultados A divisão por gravidade da Apneia Obstrutiva do Sono foi: dez pacientes apresentaram apneia na forma severa, 7 apresentaram apneia moderada, 6 tinham a forma leve e 6 estavam saudáveis. A correlação entre a nasofaringe, a orofaringe e os volumes da faringe superior e o Índice de Apneia-Hipopneia foram respectivamente: -0,415 (p = 0,025), 0,186 (p = 0,334) e -0329 (p = 0,089). A classificação de Spearman controlada pelo Índice de Massa Corporal, idade e sexo foi: -0,206 (p = 0,304), -0,155 (p = 0,439) e 0,242 (p = 0,284). Conclusão Não há correlação entre o volume da via aérea e a apneia obstrutiva do sono, avaliada pelo índice de apneia-hipopneia e controlada pelo índice de massa corporal, idade e sexo. O volume das vias aéreas superiores como parâmetro isolado não se correlacionou com a gravidade da síndrome da apneia obstrutiva do sono, e deve ser avaliado em conjunto com outros fatores.

Measurement of pharyngeal segments in Obstructive Sleep Apnea / Mensuração dos segmentos faríngeos na Apneia Obstrutiva do Sono

Objective: Obstructive Sleep Apnea (OSA) occurs by recurrent collapse of the upper airway during sleep. It results in complete (apnea) or partial (hypopnea) reduction of airflow and has intimate relation with the upper airway anatomy. Cephalometric analysis has been used to quantify airway dimensions. The aim of this study is evaluate the correlation between the anteroposterior dimension of the upper airway and the severity of obstructive sleep apnea. Material and Methods: A retrospective analysis was performed reviewing polysomnographic data (AHI) and anteroposterior cephalometric measurements of pharynx subregions: nasopharynx, oropharynx, hypopharynx. Results: The sample consisted of 30 patients. The mean body mass index was 29.60 kg/m2 and the average age was 46.8 years. Nine patients presented severe OSA, seven had moderate OSA, seven had mild OSA, and seven were healthy. The Pearson's correlation index between the anteroposterior dimension of the nasopharynx, oropharynx and hypopharynx and AHI was respectively -0.128 (p=0.517), -0.272 (p=0.162) and -0.129 (p=0.513). Conclusion: The correlation between anteroposterior linear dimension of the airway and OSA severity, assessed by AHI, was not positive. As an isolated parameter it did not correlate to the severity of the obstrucive sleep apnea syndrome and should be evaluated in conjunction with other factors. (AU)

Objetivo: A Apneia Obstrutiva do Sono (SAHOS) ocorre por um colapso recorrente da via aérea superior durante o sono. Isto resulta na redução completa (apneia) ou parcial (hipopneia) do fluxo de ar, e apresenta relação íntima com a anatomia das vias aéreas superiores. A análise cefalométrica tem sido utilizada para quantificar as dimensões das vias aéreas. O objetivo deste estudo foi avaliar a correlação entre a dimensão anteroposterior da via aérea superior e a gravidade da SAHOS. Material e Métodos: Foi realizada a análise retrospectiva dos dados polissonográficos (IAH) e medidas cefalométricas anteroposteriores das sub-regiões da farínge: nasofaringe, orofaringe e hipofaringe. Resultados: A amostra foi composta por 30 pacientes. O índice médio de massa corporal foi de 29,60 kg/m2 e a média de idade foi de 46,8 anos. Nove pacientes apresentaram SAHOS grave, 7 SAHOS moderada, 7 SAHOS leve e 7 eram saudáveis. O índice de correlação de Pearson entre a dimensão anteroposterior da nasofaringe, orofaringe e hipofaringe com IAH foi -0,128 (p=0,517), -0,272 (p=0,162) e -0,1229 (p=0,513), respectivamente. Conclusão: A correlação entre a dimensão linear anteroposterior da via áerea e a gravidade da SAHOS, avaliada por meio da IAH, não foi positiva. Como parâmetro isolado, a análise cefalométrica não foi correlacionada com a severidade da SAHOS e portanto, deve ser avaliada em conjunto com outros fatores. (AU)

Influence of different setups of the Frankfort horizontal plane on 3-dimensional cephalometric measurements.

INTRODUCTION: The Frankfort horizontal (FH) is a plane that intersects both porions and the left orbitale. However, other combinations of points have also been used to define this plane in 3-dimensional cephalometry. These variations are based on the hypothesis that they do not affect the cephalometric analysis. We investigated the validity of this hypothesis. METHODS: The material included cone-beam computed tomography data sets of 82 adult subjects with Class I molar relationship. A third-party method of cone-beam computed tomography-based 3-dimensional cephalometry was performed using 7 setups of the FH plane. Six lateral cephalometric hard tissue measurements relative to the FH plane were carried out for each setup. Measurement differences were calculated for each pair of setups of the FH plane. The number of occurrences of differences greater than the limits of agreement was counted for each of the 6 measurements. RESULTS: Only 3 of 21 pairs of setups had no occurrences for the 6 measurements. No measurement had no occurrences for the 21 pairs of setups. Setups based on left or right porion and both orbitales had the greatest number of occurrences for the 6 measurements. CONCLUSIONS: This investigation showed that significant and undesirable measurement differences can be produced by varying the definition of the FH plane.

Automatic repositioning of jaw segments for three-dimensional virtual treatment planning of orthognathic surgery.

PURPOSE: To develop a computer-based method for automating the repositioning of jaw segments in the skull during three-dimensional virtual treatment planning of orthognathic surgery. The method speeds up the planning phase of the orthognathic procedure, releasing surgeons from laborious and time-consuming tasks. MATERIALS AND METHODS: The method finds the optimal positions for the maxilla, mandibular body, and bony chin in the skull. Minimization of cephalometric differences between measured and standard values is considered. Cone-beam computed tomographic images acquired from four preoperative patients with skeletal malocclusion were used for evaluating the method. RESULTS: Dentofacial problems of the four patients were rectified, including skeletal malocclusion, facial asymmetry, and jaw discrepancies. CONCLUSIONS: The results show that the method is potentially able to be used in routine clinical practice as support for treatment-planning decisions in orthognathic surgery.

Finite Element Evaluation of Stable Fixation in Combined Mandibular Fractures.

PURPOSE: The fixation of combined mandibular fractures, especially symphyseal-condylar fractures, although occurring commonly and having a higher complication rate in the clinic, is rarely investigated regarding predictable therapeutic approaches. Thus this study's aim was to assess different forms of condylar fixation when combined with symphyseal fracture fixation. MATERIALS AND METHODS: Using finite element models, we analyzed the stress distribution that occurs when a condylar fracture is fixed with 1 miniplate, 2 miniplates, or a trapezoidal condylar miniplate and when a symphyseal fracture is fixed with 2 parallel plates, 2 perpendicular plates, or 2 lag screws. The null hypothesis was that there would be no differences among the different fixation techniques. RESULTS: The results showed a stress concentration in the anterior region of the condyle, close to the sigmoid notch. Moreover, adequate fixation in the symphysis could result in less tension at the condylar region. Therefore, when the symphysis was fixed with a lag-screw technique, condylar fixation was less required, showing a more adequate stress distribution when the condyle was fixed with 1 or 2 plates. Conversely, when the symphyseal fixation was less effective, by use of perpendicular plates, there was a change in the stress distribution at the condylar region, altering fixation behavior and resulting in more tension and displacement in the condyle, especially when a trapezoidal plate was used. CONCLUSIONS: A lag screw and parallel double plates appear to be suitable for symphyseal fixation, whereas 2 straightly positioned plates and a trapezoidal plate are suitable for condylar fixation. However, the combination of perpendicular plates in symphyseal fixation and a trapezoidal plate in condylar fixation showed an altered stress distribution.

Volumetric evaluation of pharyngeal segments in obstructive sleep apnea patients.

INTRODUCTION: Obstructive sleep apnea occurs by recurrent collapse of the upper airway during sleep, resulting in total (apnea) or partial (hypopnea) reduction of the airflow and has intimate relation with changes in the upper airway. Cone Beam CT allows the analysis of the upper airway and its volume by three-dimensional reconstruction. OBJECTIVE: To evaluate a possible correlation between the volume of the upper airway and the severity of the obstructive sleep apnea. METHODS: A retrospective study was performed reviewing polysomnographic data and Cone Beam CT records of 29 patients (13 males and 16 females). The correlation between the volume of the nasopharynx, the oropharynx and the total superior pharynx with the AHI was assessed by Pearson's rank correlation coefficient. RESULTS: The obstructive sleep apnea severity division was: ten patients had severe, 7 had moderate, 6 had mild and 6 of them were healthy. The correlation between the nasopharynx, the oropharynx and the total superior pharynx volumes and the Apnea-Hypopnea-Index was respectively: -0.415 (p=0.025), 0.186 (p=0.334) and -0329 (p=0.089). The Spearman's rank controlled by the Body Mass Index, the age and the gender was: -0.206 (p=0.304), -0.155 (p=0.439) and 0.242 (p=0.284). CONCLUSION: There is no correlation between the volume of the airway and the obstructive sleep apnea, assessed by Apnea-Hypopnea-Index and controlled by the Body Mass Index, the age and the gender. The volume of the upper airways as an isolated parameter did not correlate to the severity of the obstructive sleep apnea syndrome, and should be evaluated together with other factors.

Evaluation of Nasal Obstruction in Various Sagittal Skeletal Deformity of Jaws.

Nasal obstruction (NO) is a common symptom present in 25% of the general population, which significantly interferes with the quality of life. The different facial profiles and malocclusion patterns could be associated with the degree of NO. In order to evaluate the nasal function in patients with different facial morphology patterns, the authors developed a prospective study in which 88 patients from a dentofacial deformities center were included. These patients were submitted to fibrorhinoscopy (Mashida, ENT PIII) with a 3.2-mm cannula under topical anesthesia to evaluate septal deviation, inferior and medium turbinates, and pharyngeal tonsils. The 88 patients included in the study were divided into 3 groups according to the classification of the facial profile, distributed as follows: 32 class I, 28 class II, and 28 class III; the data collected was statistically analyzed by analysis of variance and the results are shown. The patients included in this study presented similar prevalence of NO with the reduction of airway function efficiency. Although it was not a statistically different, the group II presented higher mean Nasal Obstruction Syndrome Evaluation scores.

Analysis of Mandibular Test Specimens Used to Assess a Bone Fixation System.

The aim of this study was to assess through biomechanical testing if different synthetic materials used to fabricate test specimens have a different biomechanical behavior in comparison with other materials when simulating in vitro load resistance of a fixation method established for sagittal split ramus osteotomy (SSRO). Thirty synthetic and standardized human hemimandible replicas with SSRO were divided into three groups of 10 samples each. Group A-ABS plastic; Group B-polyamide; and Group C-polyurethane. These were fixated with three bicortical position screws (16 mm in length, 2.0-mm system) in an inverted l pattern using perforation guide and 5-mm advancement. Each sample was submitted to linear vertical load, and load strength values were recorded at 1, 3, 5, 7, and 10 mm of displacement. The means and standard deviation were compared using the analysis of variance (p < 0.05) and the Tukey test. A tendency for lower values was observed in Group B in comparison with Groups A and C. At 3 and 5 mm of displacement, a difference between Groups A and C was found in comparison with Group B (p < 0.05). At 7 and 10 mm of displacement, a difference was found among the three groups, in which Group C showed the highest values and Group B the lowest (p < 0.05). Taking into consideration the results obtained and the behavior of each material used as a substrate, significant differences occurred among the materials when compared among them.

Biomechanical comparison of four mandibular angle fracture fixation techniques.

The aim of this study was to make a comparison of the biomechanical behavior of four different internal fixation systems for mandibular angle fractures. A total of 40 polyurethane mandible replicas were employed with different fixation methods: group 1SP, one 2.0-mm four-hole miniplate; group 2PPL, two 2.0-mm four-hole parallel miniplates; group 3DP, one 3D 2.0-mm four-hole miniplate; and group 3DPP, one 3D 2.0-mm eight-hole miniplate. Each group was subjected to incisal or homolateral molar region loading. The load resistance values were measured at load application causing tip displacement of 1, 3, and 5 mm, and at the time at which the system achieves its maximum strength (MS). Means and standard deviations were compared among groups using analysis of variance and the Tukey test. Group 2PPL showed higher strength for all the displacements. For incisal loading, no statistically significant differences were found between groups 1SP, 3DP, and 3DPP. For molar loading, group 1SP and 3DPP showed statistically significant differences. For MS testing, group 1SP and 2PPL showed statistically significant differences in incisal loading; group 1SP and 3DP showed no statistically significant differences; and group 3DPP showed lower values of strength. Two parallel miniplates provide the most favorable mechanical behavior under the conditions tested.