Three-dimensional accuracy of virtual planning in orthognathic surgery.

INTRODUCTION: This study aimed to assess the accuracy of virtual surgical planning (VSP) performed by Dolphin Imaging software (version 11.9; Dolphin Imaging and Management Solutions, Chatsworth, Calif). METHODS: Ten people requiring bimaxillary surgery and genioplasty were followed up prospectively. All patients had preoperative cone-beam computed tomography, plaster models, and photographs allowing for VSP. Interocclusal intermediate surgical splints were produced using a 3-dimensional (3D) printer. Postoperative images were acquired 15 days after surgery using cone-beam computed tomography. ITK-Snap (version 3.6; Cognitica, Philadelphia, Pa) allowed the segmentation of reliable 3D models. Geomagic Qualify 2013 (3D Systems, Rock Hill, SC) and MeshValmet (version 3.0) were used to identify the differences between VSP and actual surgical results through the root mean square values and the 3D translational displacement (3-axes) of the 3D centroid of each model. RESULTS: Discrepancies between the VSP and the actual result were found at the mandible (P = 0.013) and the chin (P = 0.013) when considering the root mean square values. In addition, 3D centroid differences were found in the transverse and sagittal direction of the right ramus (P = 0.034 and P = 0.005, respectively) and the sagittal aspect of the left ramus (P = 0.025). Considering 2 mm as a threshold of clinical relevance, almost all the bone fragments (maxilla, proximal, and distal mandibular segments) were accurately corrected by surgery, although not in the chin. CONCLUSIONS: On the basis of the obtained values, it is possible to consider the Dolphin Imaging software as clinically acceptable for performing virtual orthognathic surgical planning.

Metodologia de quantificação das translações de modelos tridimensionais de acordo com um sistema de coordenadas cartesiano / Methodology for quantifying the translations of tridimensional models according to a Cartesian coordinate system

O presente estudo se propõe a validar uma metodologia de sobreposição tridimensional em tomografia computadorizada de feixe cônico (CBCT), que possa ser utilizada para avaliação de deslocamentos ocorridos em estruturas que não modificam sua forma anatômica. No software Dolphin Imaging® utilizou-se CBCT de 10 pacientes, nas quais realizaram-se movimentações cirúrgicas escolhidas aleatoriamente, de acordo com o envelope de discrepância de Proffit. Foi gerado também o modelo das regiões anatômicas de interesse (maxila e mandíbula) com o software ITK-SNAP®, pois este apresenta qualidade de superfície melhor do que os modelos obtidos com o Dolphin Imaging®. Os arquivos foram levados ao programa Geomagic Qualify®, no qual colocaram-se os modelos obtidos no ITK-SNAP® na posição espacial dos modelos obtidos no Dolphin Imaging®, para então ser realizada a avaliação dos movimentos. Para cada estrutura (maxila inicial e simulada e mandíbula inicial e simulada) foi criado um ponto (centroide) automaticamente pelo software. Através das mudanças ocorridas nas coordenadas X, Y e Z do centroide das estruturas simuladas relacionando-as com as estruturas iniciais, pôde-se observar as movimentações ocorridas. A criação de um modelo de transferência de coordenadas (MTC) que permite que as estruturas avaliadas estejam no mesmo sistema de coordenadas foi necessária. A normalidade da amostra foi verificada através do teste Shapiro-Wilk. A metodologia foi realizada por dois avaliadores e repetida após 15 dias. O teste t de uma amostra mostrou que não há diferença estatisticamente significativa tanto na maxila quanto na mandíbula para os dois avaliadores. A correlação intraclasse e os gráficos de Altman-Bland demonstraram uma correlação e uma concordância excelente, respectivamente. Pode-se concluir que a metodologia utilizada demonstrou ótima precisão e acurácia em determinar quantitativamente os deslocamentos nos três eixos do espaço, das estruturas avaliadas, além de excelente confiabilidade inter-examinador(AU)

This study proposes to validate a methodology of 3D superimposition in cone bean computed tomography (CBCT) that can be used for evaluation of displacements occurring in structures that do not change their anatomical shape. In the Dolphin Imaging® software, CBCT of 10 patients were used, in which randomly chosen surgical movements were performed according to the envelope of discrepancy of Proffit. The model of the regions of interest (maxilla and mandible) was also generated with ITK-SNAP® software, as it presents better surface quality than the models obtained with Dolphin Imaging®. The files were imported to Geomagic Qualify®, in which the models obtained in ITK-SNAP® were placed in the same spacial position than the models in the Dolphin Imaging®. Then, the evaluation of the movements was performed. For each structure (initial and simulated maxilla and initial and simulated mandible) a point (centroid) was created automatically by the software. Through the changes in coordinates X, Y e Z, in the centroid of simulated structures, relating them to the initial structures, it was possible to observe the occurred movements. It was also necessary to create a coordinate transfer model (CTM) which allows the evaluated structures to be in the same coordinate system. The normality of the sample was verified by the Shapiro-Wilk test. The methodology was performed by two evaluators and repeated after 15 days. The one-sample t-test showed no statistically significant difference in both the maxilla and the mandible for both evaluators. Intraclass correlation and the Altman-Bland showed excellent correlation and agreement, respectively. It can be concluded that the methodology used showed great precision and accuracy in determining quantitatively the displacements in the three axes of the space, of the evaluated structures, as well as excellent inter-examiner reliability(AU)

Severe root resorption resulting from orthodontic treatment: prevalence and risk factors.

OBJECTIVE: To assess the prevalence of severe external root resorption and its potential risk factors resulting from orthodontic treatment. METHODS: A randomly selected sample was used. It comprised conventional periapical radiographs taken in the same radiology center for maxillary and mandibular incisors before and after active orthodontic treatment of 129 patients, males and females, treated by means of the Standard Edgewise technique. Two examiners measured and defined root resorption according to the index proposed by Levander et al. The degree of external apical root resorption was registered defining resorption in four degrees of severity. To assess intra and inter-rater reproducibility, kappa coefficient was used. Chi-square test was used to assess the relationship between the amount of root resorption and patient's sex, dental arch (maxillary or mandibular), treatment with or without extractions, treatment duration, root apex stage (open or closed), root shape, as well as overjet and overbite at treatment onset. RESULTS: Maxillary central incisors had the highest percentage of severe root resorption, followed by maxillary lateral incisors and mandibular lateral incisors. Out of 959 teeth, 28 (2.9%) presented severe root resorption. The following risk factors were observed: anterior maxillary teeth, overjet greater than or equal to 5 mm at treatment onset, treatment with extractions, prolonged therapy, and degree of apex formation at treatment onset. CONCLUSION: This study showed that care must be taken in orthodontic treatment involving extractions, great retraction of maxillary incisors, prolonged therapy, and/or completely formed apex at orthodontic treatment onset.

Severe root resorption resulting from orthodontic treatment: Prevalence and risk factors

OBJECTIVE: To assess the prevalence of severe external root resorption and its potential risk factors resulting from orthodontic treatment. METHODS: A randomly selected sample was used. It comprised conventional periapical radiographs taken in the same radiology center for maxillary and mandibular incisors before and after active orthodontic treatment of 129 patients, males and females, treated by means of the Standard Edgewise technique. Two examiners measured and defined root resorption according to the index proposed by Levander et al. The degree of external apical root resorption was registered defining resorption in four degrees of severity. To assess intra and inter-rater reproducibility, kappa coefficient was used. Chi-square test was used to assess the relationship between the amount of root resorption and patient's sex, dental arch (maxillary or mandibular), treatment with or without extractions, treatment duration, root apex stage (open or closed), root shape, as well as overjet and overbite at treatment onset. RESULTS: Maxillary central incisors had the highest percentage of severe root resorption, followed by maxillary lateral incisors and mandibular lateral incisors. Out of 959 teeth, 28 (2.9%) presented severe root resorption. The following risk factors were observed: anterior maxillary teeth, overjet greater than or equal to 5 mm at treatment onset, treatment with extractions, prolonged therapy, and degree of apex formation at treatment onset. CONCLUSION: This study showed that care must be taken in orthodontic treatment involving extractions, great retraction of maxillary incisors, prolonged therapy, and/or completely formed apex at orthodontic treatment onset. .

OBJETIVO: avaliar a prevalência de reabsorções radiculares externas severas e identificar prováveis fatores de risco decorrentes do tratamento ortodôntico. MÉTODOS: utilizou-se uma amostra selecionada aleatoriamente, composta de radiografias periapicais de incisivos superiores e inferiores, obtidas no mesmo centro radiológico, de pré- e pós-tratamento ortodôntico ativo, de 129 pacientes, de ambos os sexos, tratados por meio da técnica Edgewise Standard. Dois examinadores mensuraram e definiram a reabsorção radicular de acordo com índice proposto por Levander et al., e o grau de reabsorção foi registrado, definindo a reabsorção em quatro graus de severidade. Para avaliar a reprodutibilidade intra- e interexaminadores, adotou-se o índice de coeficiente kappa ponderado. O teste chi-quadrado (χ2) foi adotado para avaliar a relação entre a quantidade de reabsorção radicular e o sexo dos pacientes, arcada dentária (superior ou inferior), tratamentos com ou sem extrações, duração do tratamento, forma radicular, estágio do ápice radicular (aberto ou fechado), overjet e overbite no início do tratamento. RESULTADOS: os incisivos centrais superiores apresentaram a maior porcentagem de reabsorção radicular severa, seguidos dos incisivos laterais superiores e dos incisivos laterais inferiores. Entre 959 dentes avaliados, 28 (2,9%) apresentaram reabsorção radicular severa. Os fatores de risco relacionados foram: dentes localizados na região anterossuperior, overjet maior ou igual a 5mm ao início do tratamento, tratamentos envolvendo extrações dentárias, tempo prolongado de terapia e formação radicular completa à época do início do tratamento ortodôntico. CONCLUSÃO: o estudo demonstrou que cuidados devem ser tomados em tratamentos ortodônticos envolvendo extrações, com grande retração de incisivos superiores, tratamentos prolongados e/ou ápice radicular completamente formado no início da terapia ortodôntica. .

The impact of nonsyndromic oral clefts on family quality of life.

This study aimed to assess the impact of nonsyndromic oral cleft (NSOC) on families' quality of life (QoL) using the Brazilian version of the Family Impact Scale (B-FIS). A hospital-based case-control study was conducted with NSOC cases and unaffected controls recruited at Dental Clinic in Federal University. The mean B-FIS scores were 10.32 (SD 6.53) and 5.04 (SD 4.73), while the median scores were 9.00 and 3.50 (p < .05 Wilcoxon test), respectively, in case and control group. The "parental/family activity" subscale had the highest impact average score in case (5.62 SD 3.76) and control group (3.00 SD 3.08) (p < .05 Mann-Whitney test). The types of cleft with the most impact were cleft lip (12.00 SD 8.98) and cleft lip with cleft palate (11.06 SD 6.74). NSOC affects the QoL of families with children who have this condition; however, there were no remarkable differences between the groups.