Background. Knowing the radiologic anatomy of the mandibular canal is essential to perform optimal anesthetic techniques in dentistry, especially in endodontic and surgical procedures. Bifid mandibular canals figure as anatomic variations that may hamper dental anesthesia and lead to surgical accidents.Objective. This study aims to investigate the prevalence of bifid mandibular canals in cone beam computed tomography (CBCT) images of patients under dental treatment.Material and methods. The sample consisted of 700 patients (448 females and 252 males) under dental treatment. CBCT images taken from each patient for dental treatment purposes were analyzed retrospectively in order to search for bifid mandibular canals. The detected bifid mandibular canals were classified according to their morphological arrangement and the prevalence of this anatomic variation was tested for association with patients’ sex using Pearson’s Chi-square test (2).Results. The prevalence rate of bifid mandibular canals reached 2% (n=14). Mandibular canals with an additional bifurcation towards the anterior region of the mandibular ramus were the most prevalent (100%). Lack of statistical association was observed between the occurrence of bifid mandibular canals and patients’ sex ( p >0.05).Conclusion. Despite uncommon, bifid mandibular canals may occur. Dentists must be aware of this anatomic variation to perform safely and optimally in the clinical routine.
Introduction: Research in Orthodontics and Oral Surgery has been relying on three-dimensional (3D) models to evaluate treatment results with displacement color map techniques, even though it has important limitations. Objectives: This study proposed a method of tracking translational movements of 3D objects to evaluate displacements in surfaces with no shape modification. Methods: Cone Beam Computed Tomography (CBCT) data of ten patients were imported to the Dolphin software. A hypothetical virtual surgical plan (randomly defined) was developed in the software and afterwards verified using the proposed method. All the procedures were carried out by two evaluators, in two different time-points, with a 15-day interval. ITK-Snap software was used to generate high quality STL models. Centroid points were automatically generated and their coordinates were compared to confirm if they represented the known displacements simulated. The paired t-test and the Bland-Altman plots were used, as well as the intraclass correlation coefficient. Results: Interexaminers and intra-examiner tests showed excellent reliability of the method, with mean displacement measurement error values under 0.1mm. The paired t-test did not show any statistically significant differences. Conclusion: The method showed excellent reliability to track the simulated translational displacements of bone segments.
Objective: The present study aimed to evaluate the accuracy of 3D facial soft tissue virtual models produced by two photogrammetry softwares (AgiSoft Photoscan and 3DF Zephyr Free), when compared to those created by cone beam computed tomography (CBCT). Methods: Ten patients were submitted to two sequences of photographs performed with a DSLR camera (with and without the aid of a ring flash) and CBCT scans. Each photo series for each patient was processed with the softwares, and at the end, five models of each patient were generated: 1) CBCT, 2) AAL (Agisoft Ambient Light), 3) AFL (Agisoft Flash Light), 4) ZAL (Zephyr Ambient Light), and 5) ZFL (Zephyr Flash Light). Color coded maps and root-mean-square (RMS) distances were used to compare the photogrammetry models to the CBCT ones. Results: One sample t-test showed significant differences between all methods versus CBCT. The worst results were seen in the ZAL group (discrepancies up to 5.17mm), while the best results were produced by AAL group (discrepancies up to 2.11mm). Conclusions: It can be concluded that this type of virtual facial models are reasonably accurate, although not perfect, and considering its lower biological and financial cost, they may play an important role in specific situations.
A escolha de attachments é uma das estratégias disponíveis para aumentar a área de pressão do alinhador com o dente, criando maior retenção e gerando vetores de força adicionais na direção do movimento desejado no planejamento virtual com alinhadores “in office” (AIO). Devem ser considerados como importantes elementos auxiliares desta modalidade ortodôntica, gerando maior previsibilidade e segurança ao tratamento ortodôntico. Dessa forma, o objetivo desse artigo é fornecer informações sobre o uso dos attachments mais comumente utilizados para o planejamento virtual de AIO, de acordo com a movimentação dentária. O alinhador recobre toda a superfície dentária, com isso, este dispositivo apresenta uma capacidade única de aplicar forças compressivas em todas as direções. Porém observando sua desvantagem de tensão e deformação do material plástico, constata-se a necessidade de incluir attachments com pré-requisitos distintos e conceitos biomecânicos variados. Foram realizadas simulações ilustrativas no software Archform (San Jose, EUA), de acordo com os tipos de attachments e respectivas características para favorecer o movimento planejado. Pontos cruciais como o formato, tamanho, localização, orientação e anatomia dentária influenciam a eficiência do alinhador, e foram abordados para a respectiva conduta de escolha dos attachments frente aos movimentos variados. Desta forma, para maior assertividade por parte do ortodontista na movimentação dentária que se deseja aplicar, torna-se imprescindível conhecer os tipos de attachment e suas principais indicações clínicas.
Apesar de diversas empresas oferecerem o serviço de confecção de alinhadores transparentes, a aquisição de uma impressora 3D gera ao ortodontista a possibilidade de não depender exclusivamente das mesmas. Além disso, o profissional que domina a produção de alinhadores consegue diminuir os custos, individualizar sua confecção de acordo com as necessidades do paciente, podendo planejar os casos com diferentes attachments, utilizando placas com diferentes espessuras e/ou recortes e ainda selecionar a resina mais adequada para impressão. Porém, ainda existem dúvidas com relação à utilização e aquisição de uma impressora 3D, fazendo com que os profissionais se sintam inseguros na decisão de adquiri-la. Dessa forma, visando facilitar a aquisição e utilização rotineira de uma impressora 3D, objetiva-se detalhar o passo a passo para a obtenção de um modelo 3D, descrevendo pontos importantes que devem ser avaliados quando pretende-se adquirir uma impressora 3D. Diante das diferentes tecnologias disponíveis no mercado, a estereolitografia se destaca para a confecção de alinhadores. A marca Anycubic disponibiliza opções de impressoras 3D a um excelente custo/ benefício. Pôde-se demonstrar que a utilização de uma impressora 3D para confecção de alinhadores é viável e acessível para o ortodontista, devendo o mesmo definir inicialmente o espaço disponível para os equipamentos, a quantidade de modelos que pretende imprimir e o valor que pretende investir.
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