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Statement of problem When 3-dimensional printing casts, the operator can change the type of resin and the printing layer thickness, reducing the fabrication time. However, how these parameters affect the accuracy of 3-dimensionally printed casts is unknown. Purpose The purpose of this in vitro study was to evaluate the accuracy of 3-dimensionally printed casts by using a stereolithography (SLA) 3-dimensional printer (Forms2) with 3 different layer thickness (25, 50, and 100 μm) and 2 different resins (Gray and Cast) and by comparing the time to obtain each cast. Material and Methods One master cast was scanned, and a single file was printed several times. The printed casts were then scanned by using a laboratory scanner. The standard tessellation language (STL) files provided by the laboratory scanner were superimposed and compared by using a software program (Geomagic Control; 3D Systems). The 2-way ANOVA test was used for the trueness evaluation, followed by the Tukey test to identify differences among the groups (α=.05). Results No statistically significant differences in accuracy were found among the 3 different layers for either resin (P>.05). Printing time doubled as layer thickness decreased. Conclusions This study showed that when printing casts, the fastest printing settings can be used without losing accuracy and that the laboratory digital workflow can be accelerated with selection of the resin and cast layer, as the type of resin and layer thickness did not influence the quality of the casts.

Intraoral scanners (IOSs) have some inherent distortions caused by optical and/or software imperfections. However, how other factors such as operator experience, scan time, scanner type, and scan size influence scan accuracy is not clear.The purpose of this in vitro study was to evaluate the trueness and precision of scans performed by 3 professionals with different levels of experience by using 2 IOSs.Three operators with low, medium, and high levels of experience scanned a master model 10 times by using 2 IOSs (CEREC Omnicam; Dentsply Sirona and TRIOS 3; 3Shape), resulting in 10 standard tessellation language files for each group (N=60). Each standard tessellation language file was divided into 2 areas (prepared teeth and complete arch). Precision was evaluated by comparing the 10 scans from each examiner for each system. Trueness was evaluated by comparing each scan file with a reference scan obtained from a laboratory scanner (D2000; 3Shape). A 3D analysis software program (Geomagic Control; 3D Systems) was used to perform all the comparisons and superimpositions. The 3-way ANOVA test followed by the Tukey HSD test were used to assess precision and trueness. The 2-way ANOVA followed by the Tukey HSD test was used to assess scan time. The Pearson correlation test was performed between scan time and trueness for both scanners. An additional correlation was performed between scan time and number of images, as well as between number of images and trueness for the TRIOS 3.Statistically significant influences of operator (P.001), scanner (P.001), scan size (P.001), operator and scan size (P.001), and scanner and scan size (P.001) were observed. The TRIOS 3 group reported higher precision than the CEREC Omnicam group for complete-arch scans (P.001), although no difference was observed for scans of the prepared tooth. Medium- (P=.002) and low-experience operators (P.001) reported lower precision for complete-arch scans performed with CEREC Omnicam when compared with TRIOS 3. The low-experience operator reported significantly worse results for complete-arch scans in comparison with the medium- (P=.008 and P.001) and high-experience operators (P.001 and P=.001), by using TRIOS 3 and CEREC Omnicam, respectively. Medium- and high-experience operators reported similar results among themselves. The CEREC Omnicam scanner reported lower trueness for complete-arch scans when compared with the prepared tooth (P.001); for TRIOS 3, a difference was only observed for the low-experience operator when compared with the high-experience operator (P.001). The CEREC Omnicam reported lower trueness than the TRIOS 3, except for the medium-experience operator with the prepared tooth scan. Comparing the trueness between operators and considering the same scanner and scan size, all groups were similar. The low-experience operator had a longer scanning time than the medium- and high-experience operators. For TRIOS 3, the low-experience operator obtained the highest number of images during each scan.The accuracy of intraoral scans was influenced by operator experience, type of IOSs, and scan size. More experienced operators and smaller scan sizes made for more accurate scans. In addition, more experienced operators made faster scans, and the TRIOS 3 was more accurate than the CEREC Omnicam for complete-arch scans.

To evaluate and compare the accuracy of conventional and 3D-printed casts using five different 3D printers.In the control group (CG group, n = 5), five conventional impressions using light- and heavy-body polyvinyl siloxane were obtained from the master model, resulting in five stone models. In the test groups, five different scans were performed by a well-trained and experienced clinician using a TRIOS intraoral scanner. All data were exported as an STL file format, processed, and sent to five 3D printers. Five casts were manufactured in each group: SG (CARES P20, Straumann); FG (Form 2, Formlabs); WG (Duplicator 7, Wanhao); ZG (Zenith D, Zenith); and MG (Moonray S100, Moonray). Measurements of the accuracy (trueness and precision) of the casts obtained from conventional elastomeric impressions and 3D-printing methods were accomplished using a 3D analysis software (Geomagic Control).The FG group showed the lowest values for trueness (closer to real dimensions), which were similar to the SG group only (P.05). Groups MG, WG, and ZG presented higher values and were similar compared to each other. Data on precision demonstrated that all 3D-printed groups showed lower values for precision (smaller deviation) when compared to the control group.The trueness depends on the chosen 3D printer. All of the tested 3D printers were more precise than cast models obtained from conventional elastomeric impressions.

CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico FAPEMIG - Fundação de Amparo a Pesquisa do Estado de Minas Gerais O fluxo digital na odontologia trouxe algumas mudanças na rotina clínica, como: obtenção de modelos impressos, guias cirúrgicos, próteses totais e parciais, coroas provisórias e outras possibilidades. Existem vários sistemas de impressoras 3D, tipos de resinas e escâneres que podem gerar alterações. Este estudo foi dividido em cinco objetivos específicos; Objetivo específico 1: O objetivo deste estudo in vitro foi avaliar a precisão e fidelidade de escaneamentos realizados por 3 profissionais com diferentes níveis de experiência utilizando dois escâneres intraorais e dois tamanhos de arcos. Objetivo específico 2: O objetivo deste estudo foi avaliar e comparar a acurácia de dois escâneres intraorais e modelos fabricados por impressão 3D e método convencional. Objetivo específico 3: O objetivo desse estudo foi avaliar e comparar a acurácia de modelos convencionais e impressos confeccionados por 5 diferentes impressoras 3D. Objetivo específico 4: O objetivo desse estudo foi avaliar a acurácia de modelos impressos confeccionados por 3 diferentes espessuras de impressão (25, 50 e 100 Microns) e dois tipos de resinas. Objetivo específico 5: O objetivo desse estudo foi avaliar o deslocamento e angulação de implantes dentais em modelos impressos e escaneados por dois escâneres e modelos convencionais. A acurácia dos escaneres intraorais foi influenciada pela experiência do operador, tipo de escâner e o tamanho do arco de escaneamento. Operadores mais experientes e menores tamanhos de arco geraram escaneamentos mais próximos da realidade. Diferentes impressoras 3D tiverem influência na acurácia dos modelos e as impressoras 3D foram mais precisas para a obtenção de modelos que a impressão convencional. Os laboratórios protéticos digitais podem trabalhas de forma mais rápida de acordo com a escolha da resina e camadas de espessura selecionada para impressão, porque estes fatores não influenciaram na qualidade final. Modelos impressos podem ser utilizados para a estratificação de cerâmicas em infraestruturas fresadas sobre implantes. The use of digital workflow in Dentistry brings a new reality to obtain models, surgical guides, partial and total prosthodontics, provisional crowns, and other possibilities. There are several 3D printer systems, resins and scanners types that could obtained differences. This study was divided into five specific objectives; Specific objective 1: the purpose of this in vitro study was to evaluate the trueness and precision of 2 intraoral scanning systems operated by 3 professionals with different levels of experience and with 2 scan sizes. Specific objective 2: The purpose of this study was to evaluate and compare the accuracy of two intra-oral scanners and manufactured casts by 3D printer and conventional impression methods. Specific objective 3: The aim of this study was to evaluate and compare the accuracy of conventional and 3D printed casts using five different 3D printers. Specific objective 4: The objective of this study was to evaluate the accuracy of 3D printed models with 3 different layers thickness (25, 50 and 100 microns) and using two different resins. Specific objective 5: This study aimed to evaluate the three-dimensional positioning of dental implants in casts obtained by using conventional and digital impressions. The accuracy of intraoral scans was influenced by operator experience, type of scanners, and scan size. More experienced operators and smaller scan sizes made for more accurate scans. Different 3D printers have influence in the models’accuracy and 3D printers are more precise than cast models obtained by conventional impression. The laboratorial digital workflow could be faster according to resin and model layer chosen because the type of resin and layers did not influence the quality of the tested models. Printed models could be used for stratification of milled structures over implants. Tese (Doutorado) 2022-12-21

Background: Different sizes of arch could influence in digital methods to obtaining dental impressions and 3D models. The purpose of this study was to evaluate and compare the accuracy of two intra-oral scanners and conventional impression methods for the fabrication of working casts. Methods: Conventional impressions of a reference cast were obtained. Digital impressions were obtained with two intra-oral scanners: Cerec Omnicam (CO) and 3Shape Trios (ST). The obtained digital stereolithographic casts were printed on Zenith D 3D printer. The reference cast and fabricated casts were scanned with a bench top scanner and saved in STL format. All STL records were analyzed in specific software: complete arch (CA), partial arch (PA) and prepared teeth area (PT). One-way and two-way analyses of variance were performed to compare the accuracy, followed by the Tukey test. Results: No significant intergroup differences in trueness and precision were observed for the two intra-oral scanners. 3D printed casts had the lowest trueness when complete arch was analyzed and differed statistically from the stone cast. For complete arch precision, stone cast presented better results, however statistically different only from the CO. Conclusions: The two intraoral scanner systems had similar accuracy. Stone casts had higher trueness than 3D printed casts for CA. For CA precision, 3D printed cast presented similar results to the stone cast.

CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico FAPEMIG - Fundação de Amparo a Pesquisa do Estado de Minas Gerais 0 objetivo desse estudo foi comparar a adaptação marginal de infraestruturas em zircônia confeccionadas pelo sistema CAD/CAM, utilizando dois escâneres e uma única fresadora, por meio do microscópio eletrônico de varredura (MEV). Materiais e métodos: Dez infraestruturas aparafusadas, implanto-suportadas, de três elementos foram divididas em dois grupos para avaliara adaptação marginal no modelo boca. Dez infraestruturas em zircônia foram fabricadas por uma única fresadora, cinco foram obtidas por meio do escaneamento com o escâner 7series Dental Wings e cinco com o escâner Ceramill map 400. A desadaptação vertical e horizontal da interface protética (mesial e distai de todos os implantes) foram analisadas e mensuradas pelo MEV, resultando em trinta medidas por grupo (n=30). As medidas foram obtidas em duas situações, a primeira quando um parafuso central está posicionado e a segunda com todos os parafusos apertados. A análise estatística foi realizada utilizando o teste estatístico U Mann-Whitney (a=.05) para desadaptações verticais. Os valores de desadaptações horizontais foram divididos em três situações: sobre extensão, zero e sub extensão. Resultados: Diferença estatística significante foi encontrada entre os valores de desadaptação marginal quando todos os parafusos estavam apertados, porém todos esses valores estão abaixo de 16 pm. Cinco e Dezoito valores de desadaptação horizontal foram encontrados nos escâneres 7series Dental Wings e Ceramil map 400, respectivamente. Conclusão: O uso de diferentes escâneres apresenta influencia na adaptação final de infraestruturas. The purpose of this study was to compare the fit accuracy of CAD/CAM- fabricated zirconia frameworks using two different scanners and the same milling unit by scanning electron microscopy (SEM). Material and methods. Ten 3-unit implant-supported, screw-retained frameworks were fabricated to fit a mastermodel. The same manufacturing milling unit fabricated all the frameworks using two scanners, five frameworks for each group: 7series Dental Wings and Ceramill map 400. The vertical and horizontal misfit at the implant-framework interface (mesial and distal of all implants) were measured by SEM resulting in 30 measurements per group (n=30) when only 1 screw was tightened and after all screws were tightened. The statistical analysis was performed using Mann-Whitney test (a=.05) by vertical misfit. Horizontal misfit values were separated in three situations: underextension, zero and overextension. Results: Significant difference was found between the fit accuracy of the two groups when all screws were tightened, however all values is below 16 pm. Five and eighteen horizontal misfit were found in Dental Wings and Ceramill map 400, respectively. Conclusions: The use of different scanners have influence on fit accuracy of zirconia frameworks. Dissertação (Mestrado)

A população de idosos no Brasil tem crescido em ritmo acelerado e o cirurgião dentista deve estar atento a ampliar seus conhecimentos na área da odontogeriatria para proporcionar um tratamento correto, eficaz e com conforto ao paciente idoso, já que estes apresentam alterações fisiológicas, condições sistêmicas, psicológicas e sociais decorrentes do processo de envelhecimento. O objetivo desta revisão de literatura é discutir as alterações na qualidade de vida do paciente idoso, incluindo seu reflexo emocional e efeitos psicológicos. Para tanto, foi utilizado uma pesquisa qualitativa de cunho bibliográfico de fonte secundária, método indutivo para análise e elaboração do presente trabalho. Uma das alterações é a perda dentária que tem efeitos significativos na saúde dos idosos, pois afeta a capacidade mastigatória, restringem o consumo de vários alimentos, dificultam a fonação, além dos danos estéticos. A má absorção dos nutrientes gera um desequilíbrio nutricional com prejuízo para realização e manutenção de processos orgânicos vitais, maior susceptibilidade a enfermidades e dificuldade na recuperação de doenças. A alimentação adequada pode levar a uma velhice saudável com maior capacidade funcional e menor incidência de doenças, melhorando a qualidade e estilo de vida.

Microscopic measurements are widely used in scientific research and the correct equipment to perform these evaluations could be critical to determine study results. Regarding microscopic measurements, three of the most used methods are: Optical Microscopy (OM), Scanning Electron Microscopy (SEM), and Micro-computed Tomography (MCT). It is important to select the best method for assessing diverse parameters, considering operational characteristics of the method, the equipment efficiency, and the machinery cost. Aim: Therefore, the main objective of this study was to define which is the most useful measurement method for assessing magnitudes below 0.4 mm. Methods: Ten dental implants, with known dimensions as defined by the manufacturer were randomly distributed. Two blinded observers assessed the distance between the second and the third screw vortex of the implants using three suggested methods. The true distance was defined to be 0.5 mm. Results: The assessed distances were: 0.597±0.007mm for OM, 0.578±0.017mm for SEM, and 0.613±0.006mm for MCT. The assessed distances were significantly different when the methods were compared (P>0.01). All measurements were into the CAD tolerances. Conclusion: It was possible to conclude that linear measurements between 595 and 605 μm could be performed by any of the described technologies.

Purpose To evaluate the influence of Morse taper implant index on microleakage. Materials and methods Thirty implants and abutments were divided into 3 groups (n = 10): CM1 (universal post and implant without index), CM2 (universal post and implant with index), and CM3 (abutment and implant with index). To evaluate the microleakage from the implant inner part, the implants were inoculated with Streptococcus sanguinis solution at a 0.5 McFarland and incubated for 7 days at 37°C in Eppendorf tubes with sterile broth. To evaluate the microleakage into the inner part of implant, these were inoculated with sterile Schaedler broth and immersed in a Fusobacterium nucleatum solution at a 0.5 McFarland. The samples were incubated for 30 days in an anaerobic chamber. Results Nine samples of each group of the first methodology showed no presented bacterial contamination. No samples of the second methodology demonstrated turbidity of the broth. Conclusion The presence of the prosthetic internal index had no influence on bacterial microleakage of Morse taper implants under static conditions, for both methodologies.

The aim of this study was to evaluate the influence of abutments with a prosthetic index on the fracture resistance of Morse taper dental implants. Morse taper implants were divided into 2 groups (n = 5 per group): a group with an indexed implant and a nonindexed abutment (solid Morse taper universal post; WIS group), and a group with an indexed implant and an indexed abutment (WIP group). Both groups were subjected to bending tests for fracture strength until 5 mm of displacement or implant fracture occurred. Statistical analysis was performed using the Student t test (α = 0.05). There was no statistically significant difference between the mean fracture values, which were 305.8 N and 318.6 N for the WIS group and WIP group, respectively. The presence of a prosthetic index on Morse taper abutments did not influence the resistance to fracture.