Three-Dimensional printed model for preclinical training in oral radiology.

INTRODUCTION: 3D printing is experiencing significant growth in the teaching and learning process. This study aims to present a 3D printed skull model for preclinical intraoral radiographic practice. MATERIALS AND METHODS: Two 3D printed mannequins were created. One mannequin used an STL file of a skull that was edited using two 3D modelling software (Meshmixer and Netfabb). The second mannequin was designed directly from a patient's segmented CBCT data and then converted into an STL file. Both mannequins were printed using fused deposition modelling (FDM) technology and polylactic acid (PLA) filament; teeth for the second mannequin were also printed using digital light processing (DLP). The printed skull bones were attached, the mandible was articulated to the articular fossa of the temporal bone, and the teeth were inserted into the alveoli. Intraoral radiographs of both mannequins were taken using a digital sensor (RVG 5100, Carestream). RESULTS: Both 3D printed mannequins showed satisfactory radiographic appearance, allowing geometric representation of each intraoral radiographic projection, regardless of STL file origin. Anatomical structures, such as the periodontal ligament space, zygomatic process of the maxilla and intermaxillary suture, were represented. The material cost of the first and second printed prototype was $34.00 and $39.00, respectively. CONCLUSIONS: The use of 3D printed models is presented as an alternative to artificial commercial phantoms for the preclinical training of intraoral radiographic techniques through the combined benefits of superior radiographic projection quality, the possibility of model manipulation and an affordable price.

Tomografia computadorizada multidetectores de baixa dose de radiação para avaliação de canino incluso / Low-dose multidetector computed tomography for impacted canine evaluation

Objetivo: avaliar caninos inclusos em tomografias computadorizadas multidetectores (TCMD) realizadas no Hospital Universitário de Santa Maria. Materiais e mé¬todo: foi realizado um estudo observacional transversal com imagens de um banco de dados de TCMD de baixa dose de radiação, solicitadas por indicações clínicas odontológicas. Os exames em formato digital imaging and communications in medicine foram avaliados por um examinador treinado, no software Weasis Medical Viewer. A avaliação dos exames compreendeu a observação das seguintes características: impactação do canino (uni ou bilateral), localização do canino (maxila ou mandíbula), localização da coroa do canino (vesti¬bular ou lingual/palatal), eixo de erupção, espessura do folículo pericoronário, presença de lesões associadas, presença de reabsorção nos dentes adjacentes e presença de agenesias dentárias ou de supranumerários. Os resultados foram avaliados de maneira descritiva, por meio de prevalência dos achados. Resultados: foram encontrados 21 caninos inclusos em 837 tomografias avaliadas (1,9%). Foi observado um predomínio de indivíduos do sexo feminino (71,4%), e a retenção do canino foi mais frequente na maxila (71,4%) e com impactação unilateral (61,9%). Quatro caninos apre¬sentaram folículo pericoronário, com espessura maior que 2 mm; 19% dos exames apresentaram reabsorção radicular externa em algum incisivo lateral. Apenas um canino apresentava lesão associada, sugerindo esclero-se óssea. Além dos caninos inclusos, foi possível avaliar alterações relacionadas às demais regiões e estruturas dentomaxilofaciais. Conclusão: apesar da amostra limitada de imagens, o presente estudo demonstrou a aplicabilidade clínica da TCMD com protocolo de baixa dose de radiação, para a avaliação dos caninos inclusos e características relacionadas a esses dentes, bem como de dentes e regiões adjacentes. (AU)

Objective: to evaluate impacted canines by tomographic exams performed at the University Hospital of Santa Maria. Materials and method: a cross-sectional observational study was performed with selected images from a database of low dose computed tomography (CT) scans requested by several dental indications. The DICOM files were evaluated by a trained examiner, using Weasis Medical Viewer software. The evaluation of each exam included the following characteristics: canine impaction (uni or bilateral), location of the canine (maxilla or mandible), location of the canine crown (buccal or lingual / palatal), shaft of canine eruption, thickness of the pericoronal follicle, presence of associated lesions, presence of external root resorption in adjacent teeth and presence of dental agenesis or supernumerary tooth. The results were evaluated in a descriptive way, through prevalence of the findings. Results: a total of 21 impacted canines were found in 837 CT scans evaluated (1,9%). A predominance of female patients was observed (71,4%); canine impaction was more frequent in the maxilla (71,4%), and unilateral (61,9%). In 19% of the exams, external root resorption occurred in some lateral incisor. Four dental elements presented pericoronal follicles thicker than 2 mm. In the evaluated sample, only one canine presented an associated lesion, suggesting bone sclerosis. Beyond the canine-related, other dental and maxillofacial changes were also evaluated. Conclusion: in spite of the limited sample, the present study demonstrated the clinical applicability of low dose CT for the evaluation of impacted canines, and characteristics related to these teeth, as well as to the adjacent teeth and regions. (AU)