Vertical Bone Measurements From Cone Beam Computed Tomography Images Using Different Software Packages

This article aimed at comparing the accuracy of linear measurement tools of different commercial software packages. Eight fully edentulous dry mandibles were selected for this study. Incisor, canine, premolar, first molar and second molar regions were selected. Cone beam computed tomography (CBCT) images were obtained with i-CAT Next Generation. Linear bone measurements were performed by one observer on the cross-sectional images using three different software packages: XoranCat (R), OnDemand3D (R) and KDIS3D (R), all able to assess DICOM images. In addition, 25% of the sample was reevaluated for the purpose of reproducibility. The mandibles were sectioned to obtain the gold standard for each region. Intraclass coefficients (ICC) were calculated to examine the agreement between the two periods of evaluation; the one-way analysis of variance performed with the post-hoc Dunnett test was used to compare each of the software-derived measurements with the gold standard. The ICC values were excellent for all software packages. The least difference between the software-derived measurements and the gold standard was obtained with the OnDemand3D and KDIS3D (-0.11 and -0.14 mm, respectively), and the greatest, with the XoranCAT (+0.25 mm). However, there was no statistical significant difference between the measurements obtained with the different software packages and the gold standard (p > 0.05). In conclusion, linear bone measurements were not influenced by the software package used to reconstruct the image from CBCT DICOM data.29

Influence of windowing and metal artefact reduction algorithms on the volumetric dimensions of high-density materials : a CBCT study

Orientador: Sergio Lins de Azevedo VazDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: Introdução: A alteração volumétrica de materiais de alta densidade encontra-se dentre os artefatos inerentes à tomografia computadorizada de feixe cônico (TCFC). A ferramenta de redução de artefatos metálicos (FRA) pode ser uma opção na atenuação desse artefato, atuando na etapa de reconstrução da imagem, assim como o janelamento é uma maneira de ajustar os tons de cinza representados após a reconstrução. Objetivo: Avaliar a influência do janelamento e da FRA nas dimensões volumétricas de cinco materiais de alta densidade, utilizando dois sistemas de TCFC. Material e métodos: Quatro cilindros de cinco materiais de alta densidade (amálgama, cromo-cobalto, guta-percha, titânio e zircônia) foram confeccionados e seus volumes físicos (VF) aferidos. Um fantoma de polimetilmetacrilato contendo os cilindros foi submetido a aquisições nos sistemas Picasso Trio e OP300, com a FRA ativada e desativada. Dois avaliadores segmentaram os volumes tomográficos (VT) dos cilindros utilizando o software ITK-SNAP, em duas etapas: W1 ¿ alta largura e alto nível do ajuste de janela automático; W2 ¿ baixa largura e baixo nível, reduzindo em um terço esses valores automáticos. A alteração volumétrica foi expressa como resultado da subtração entre VT e VF. As análises estatísticas compreenderam o Índice de Correlação Intraclasse (ICC) e análise de variância (ANOVA) para medidas repetidas com teste post-hoc de Tukey (a = 5%). Resultados: Os valores de ICC indicaram excelente reprodutibilidade para os VT. A alteração volumétrica foi influenciada significativamente por todos os fatores e suas interações no Picasso Trio (p<0,05) e por quase todos os fatores e suas interações considerando o OP300 (p<0,05). Guta-percha e titânio obtiveram menor alteração volumétrica, assim como o uso de W1. A ativação da FRA do sistema Picasso Trio subestimou os VT da guta-percha e do titânio e não reduziu significativamente a alteração volumétrica dos outros materiais. A não-ativação da FRA do sistema OP300 resultou em menor alteração volumétrica do que a sua ativação. Conclusão: Guta-percha e titânio apresentaram menor alteração volumétrica do que os outros materiais. Em geral, os algoritmos FRA de ambos os sistemas estudados foram ineficazes em reduzir significativamente a alteração volumétrica de materiais com alto número atômico e alta densidade. Ajustes de janela com altos valores de largura e nível podem ser realizados para avaliar materiais de alta densidade, em ambos os sistemas estudadosAbstract: Introduction: Volumetric distortion of high-density materials is one of the artefacts inherent to cone beam computed tomography (CBCT). Metal artefact reduction (MAR) algorithms act on image reconstruction and may be an option in mitigating this type of artefact, while windowing is a way of adjusting the represented shades of grey after reconstruction. Aim: To assess the influence of windowing and MAR algorithm on the volumetric dimensions of five high-density materials using two CBCT systems. Material and methods: Four cylinders of five high-density materials (amalgam, cobalt-chromium, gutta-percha, titanium and zirconia) were manufactured and their physical volumes (PV) were measured. A polymethylmethacrylate phantom containing the cylinders of each material was submitted to acquisitions in Picasso Trio and OP300 units with their MAR enabled and disabled. Two evaluators segmented the cylinders tomographic volumes (TV) using the ITK-SNAP software in two steps: W1 ¿ high window width and level of the automatic adjustment; W2 - low window width and level, reducing these automatic values by one third. Volumetric distortion was expressed as a subtraction between TV and PV. Statistical analysis comprised the Intraclass Correlation Coefficient (ICC) and Analysis of Variance (ANOVA) for repeated measures with Tukey post-hoc test (a = 5%). Results: ICC values indicated excellent reproducibility of TV. Volumetric distortion was significantly influenced by all factors and their interactions in Picasso Trio (p <0.05) and by almost all factors and their interactions considering OP300 (p <0.05). Gutta-percha and titanium obtained the smallest volumetric distortion, as did the use of W1. The activation of MAR algorithm of Picasso Trio underestimated gutta-percha and titanium TV and was inefficient to significantly reduce the volumetric distortion of the other materials. Disabling MAR algorithm of OP300 unit resulted in smaller volumetric distortion than its enabling. Conclusion: Gutta-percha and titanium had smaller volumetric distortion than the other materials. In general, MAR algorithms of both systems were inefficient to significantly reduce the volumetric distortion of high-atomic number and high-density materials. High window width and level can be used to evaluate high-density materialsMestradoRadiologia OdontologicaMestra em Radiologia Odontológica88882.434511/2019-01CAPE

Confección de Prótesis Maxilofacial Ósea, In Silico, a Partir de la Impresión 3D a Través de la Tomografía Cone Beam, Arequipa 2019

Esta investigación tuvo como objetivo de demostrar que se puede obtener prótesis maxilofaciales para reemplazar tejido óseo perdido por medio de tomografías e impresoras 3D. Se trata de un estudio experimental en el cual se utilizó un cráneo donde se le hicieron 3 osteotomías, en la calota en el parietal izquierdo, apófisis temporal del maxilar y la apófisis zigomática, simulando traumatismos en el cráneo facial. Siendo así, fue adquirida las imágenes 3D por Tomografía Cone Beam para luego analizar las estructuras dañadas. Seguidamente, el formato DICOM (Digital Imaging and Communications in Medicine / Imagen Digital y Comunicación en Medicina) del estudio fue transformado en sólido utilizando el programa InVesalius para luego trabajarlo en el programa Blender donde se duplicó el cráneo, se espejó y se rellenaron las partes óseas faltantes donde se trataron para su posterior impresión. Utilizando el programa PreForm, fueron colocadas las estructuras y fueron impresas en la impresora 3D FormLabs Form 2 donde se obtuvieron las estructuras en sólido. Se esperó a que se polimerizaran para luego colocarlas en las zonas óseas faltantes del cráneo. Se puedo concluir que es factible de realizar prótesis maxilofaciales óseas por impresión 3D utilizando imágenes tomográficas, programas de uso libre e impresoras 3D de escritorio, con un alto grado de precisión. Palabras clave Prótesis maxilofacial, impresión 3DTesi

Assessment of the accuracy of craniofacial linear measurements on horos software

Introdução: Na antropometria craniofacial avaliam-sequantitativamente as estruturas anatômicas faciais, e as tomografias computadorizadas de feixecônico (TCFC) têm contribuído significativamente para refinar essa abordagem. A análise antropológica e morfológica do crânio para estimativa de idade, ou a avaliação das espessuras de tecidos moles faciais para aproximação facial forense, podem ser beneficiadas com o avanço das ferramentas de reconstrução e visualização de imagens de TCFC em softwares open sourcecomo o HorosTM. Objetivo: Avaliar a confiabilidade e a precisão de medidas lineares realizadas em TCFC em Reconstrução Multiplanar (MPR), no modo de visualização de MIP, nas espessuras de corte mínima (Emín) e máxima (Emáx). Material e método: Foram selecionados 17 crânios pertencentes ao biobanco do Laboratório de Antropologia e Odontologia Forense da Universidade de São Paulo (OFLab-FOUSP) para a mensuração de 10 grandezas lineares, aferidas de três maneiras distintas:uma diretamente sobre o crânio (padrão-ouro) e duas no software (em Emín e Emáx). Para a análise estatística foi adotado o nível de significância de 5%. Resultados: O CCI (Coeficiente de Concordância Intra-classe) inter e intra-examinadores foi excelente. A consistência das medidas entre os métodos, nos grupos A (crânio-Emín) e B (crânio-Emáx) foi verificada pela análise de Bland-Altman. O grupo B apresentou maior precisão de medidas, porém, a diferença menor do que 1 mm encontrada no grupo A não compromete a análise craniométrica. Conclusão: Ambos os métodos são confiáveis para mensurações lineares.Introduction: In craniofacial anthropometry, facial anatomical structures are quantitatively evaluated, and cone beam computed tomography (CBCT) has significantly contributed to refine this approach. Anthropological and morphological analysis of the skull for age estimation or, assessment of facial soft tissue thickness for forensic facial approximation, can be benefited by advancement of CBCT image reconstruction and visualization tools at open-source software such as HorosTM. Objective: This study verified the reliability and accuracy of linear measurements performed in CBCT in Multiplanar Reconstruction (MPR), in MIP visualization mode, at minimum (STmin) and maximum (STmax) slab thicknesses. Material and Method: 17 skulls from biobank of the Laboratory of Forensic Anthropology and Dentistry of University of São Paulo (OFLab-FOUSP) were selected for measurement of 10 linear distances, measured in three different ways, one directly on the skull (gold standard) and two in software (in STmin and STmax). For statistical analysis, the significance level of 5% was adopted. Results: Inter-and intra-examiner ICC (Intraclass Correlation Coefficient) was excellent. The consistency of measurements between the methods in groups A (skull-STmin) and B (skull-STmax) was verified by Bland-Altman analysis. Group B showed greater measurement accuracy than group A. However, differences found in group A was smaller than 1 mm, and it does not compromise the craniometric analysis. Conclusion: Both methods are reliable for linear measurements

RIDGE PRESERVATION FOLLOWING TOOTH EXTRACTION

Tooth extraction initiates a complex bone modelling and remodelling process, leading to undesirable vertical and horizontal topographic changes. Alveolar Ridge Preservation (ARP) techniques have been developed, to promote physiological healing at the alveolus, reducing the bone and soft-tissue dimensional change, enabling future implant placement. Unfortunately, the outcomes associated with ARP procedures are inconclusive. The PhD was designed to compare linear and cross-sectional alveolar ridge dimensions, mucosal characteristic, composition of new bone and implant outcomes measures, following ARP. Unassisted socket healing acted as the Control. The study used two systematic reviews, to answer the questions: Does ARP following tooth extraction improve implant treatment, and what are the hard and soft tissue changes following ARP at 4-months healing. The reviews indicated ARP did not affect implant success or survival in an augmented socket. Limited evidence was present, to support the benefits of ARP in reducing the requirement for bone augmentation at implant placement. ARP was associated with preservation of the alveolar ridge height and a variable reduction in alveolar ridge width. Evidence did not identify the superiority of a particular ARP technique, when evaluating bone and soft tissue dimensional changes, gingival tissue characteristics, bone healing and patient outcome measures. These observations led to the development of a single blinded, randomised controlled trial, that compared Guided Bone Regeneration (GBR) and Socket Seal (SS) ARP technique, with the Control. The results indicated that GBR ARP, was effective at preserving the coronal buccal socket contour, reducing the vertical, horizontal and socket-area bone dimensions, whilst stabilising soft-tissue contours and mucosal topography. SS offered an advantage in vertical contour preservation. ARP techniques resulted in less new bone formation than the Control, with GBR requiring a reduced need for further augmentation at implant placement (ANOVA-Tukey/p<0.05). The use of an ARP technique did not affect implant success and survival

3D Innovations in Personalized Surgery

Current practice involves the use of 3D surgical planning and patient-specific solutions in multiple surgical areas of expertise. Patient-specific solutions have been endorsed for several years in numerous publications due to their associated benefits around accuracy, safety, and predictability of surgical outcome. The basis of 3D surgical planning is the use of high-quality medical images (e.g., CT, MRI, or PET-scans). The translation from 3D digital planning toward surgical applications was developed hand in hand with a rise in 3D printing applications of multiple biocompatible materials. These technical aspects of medical care require engineers’ or technical physicians’ expertise for optimal safe and effective implementation in daily clinical routines.The aim and scope of this Special Issue is high-tech solutions in personalized surgery, based on 3D technology and, more specifically, bone-related surgery. Full-papers or highly innovative technical notes or (systematic) reviews that relate to innovative personalized surgery are invited. This can include optimization of imaging for 3D VSP, optimization of 3D VSP workflow and its translation toward the surgical procedure, or optimization of personalized implants or devices in relation to bone surgery

La Tc Cone Beam in chirurgia ortognatica: lo stato dell'arte

Una percentuale sempre maggiore di persone con malocclusioni severe necessita di essere trattata attraverso interventi di chirurgia ortognatica. Dal sondaggio Statunitense sulla Salute e Nutrizione (NHANES III)(1) il 2.7% della popolazione americana presenta una anomalia dento- facciale che contribuisce ad una malocclusione la quale richiede un trattamento chirurgico per la sua correzione. Fino a qualche anno fa gli interventi di chirurgia ortognatica venivano eseguiti esclusivamente in base a studi pre-chirurgici effettuati con esami radiografici bidimensionali quali ortopantomografia e teleradiografia latero-laterale, portandosi dietro di conseguenza tutti gli errori che possono derivare da immagini bidimensionali rispetto ad una struttura tridimensionale. Il presente lavoro si propone di enfatizzare l’importanza della programmazione virtuale in chirurgia ortognatica mediante l’ausilio della Tomografia Computerizzata a fascio conico (Tc Cone Beam) e analizza gli aspetti tecnici al fine di diagnosticare la malocclusione, impostare l’intervento chirurgico e predire il risultato finale con la maggior precisione possibile e, soprattutto, con le caratteristiche di tridimensionalità introdotte dalla Tc Cone Beam, fino a poco tempo fa sconosciute alla comunità scientifica. Nuovi sviluppi in questo settore potrebbero portare a sistemi morfometrici 3D completi, comprendenti anche sistemi di misurazione basati in volume; inoltre potrebbero anche portare a informazioni di forma 4D che integra l'evoluzione nel tempo dell'analisi, il tutto per ottenere informazioni sempre più complete e in tempi sostanzialmente minori