A perda óssea progressiva ao redor da plataforma dos implantes dentários é um desafio a ser vencido na clínica, uma vez que, interfere na manutenção e controle dos tecidos peri-implantares e pode afetar a estética. Esta pesquisa teve como objetivo avaliar a concentração de tensões ao redor de diferentes implantes dentários, variando a macrogeometria, conexão protética e profundidade da inserção da plataforma protética, sob carregamento axial ou oblíquo. Foram criados três modelos de resina fotoelástica para cada tipo de implante avaliado (hexágono externo, hexágono externo wedge, hexágono interno e cone Morse). Cada corpo de prova se diferenciou pelo posicionamento da plataforma do implante em relação à margem superior do bloco, em três posições diferentes: I - plataforma posicionada 2mm abaixo da margem do bloco; II - plataforma posicionada no mesmo nível da margem do bloco; III - plataforma posicionada 2mm acima da margem do bloco. Foi aplicada uma força de 100N através de um dispositivo instalado sobre pilares retos e angulados, simulando um carregamento axial e oblíquo respectivamente. Um total de 4 pontos foram avaliados de um lado do implante. Dados quantitativos foram coletados e utilizados para análise estatística. A regressão linear múltipla mostrou relação entre a distribuição das tensões com relação à profundidade de inserção independentemente do tipo de conexão protética ou do carregamento oclusal. O grupo I (2mm abaixo da margem) foi o que apresentou os menores valores (p<0.05) de tensão quando comparado com os outros grupos (II e III). De acordo com as limitações deste estudo pode-se concluir que a macrogeometria, profundidade de inserção da plataforma e tipo de carregamento oclusal influenciam no comportamento da distribuição das tensões ao redor dos implantes. Em relação à conexão protética, os resultados mostraram padrões de franjas semelhantes independentemente do tipo de conexão / The progressive bone loss at the neck of dental implant is a clinical concern since it affects the maintenance of dental esthetics. The stress concentration, the connection type and the microgap appear to be factors that cause alterations at the marginal bone level. The aim of this research was to evaluate the stress concentration around different dental implants, varying the macrogeometry, prosthetic connection and depth of the insertion of the prosthetic platform, under axial or oblique loading. Three blocks of photoelastic resin for each type of implant connection (external hexagon, external hexagon flattened, internal hexagon and Morse taper) were built. Each block differed in the position of the implant platform in relative to the upper margin of the block: I (2mm below), II (at the same level) and III (2mm above). A force of 100N was applied to both a straight and tilted abutments. A multiple linear regression showed the relation between the stress distribution and the insertion depth. For all the implant types, both with straight and tilted abutments, Group I presented the lowest stress concentration around the fixture when compared to group II and III (p<0,05). According to the limitations of this study it could be concluded that the macrogeometry, depth of insertion of the platform and type of occlusal loading influence the behavior of the distribution of stresses around the implants. Regarding the prosthetic connection, the results showed similar patterns of fringes regardless of the type of connection

En los últimos años, la tendencia en la odontología restauradora es la conservación al máximo de los tejidos dentarios remanentes, siendo esto así, lo que se buscan son alternativas diferentes para poder rehabilitar la perdida de piezas en los pacientes que se acercan a la consulta. Las prótesis híbridas adhesivas combinan una prótesis fija convencional (coronas) con aditamentos de un mínimo desgaste (carillas). Se presenta un caso clínico de un paciente de 43 años de edad de sexo masculino que acudió a la clínica de la Universidad Peruana de Ciencias Aplicadas (UPC) en el año 2018 por presentar fractura corono radicular de un incisivo central superior, pilar de una prótesis parcial fija que provocaba la movilidad de la prótesis y alteraba la estética. Se planificó una prótesis híbrida que combinó una corona cerámica libre de metal en el incisivo central y carillas cerámicas (vestibular y palatino) en el incisivo lateral. El caso clínico evidenció una mejora de la estética, preservó tejidos dentarios y mejoró la satisfacción por parte del paciente con respecto a su sonrisa. La combinación de una prótesis convencional libre de metal y las carillas cerámicas son una alternativa eficiente para el manejo del edentulismo parcial antero superior con un mínimo de desgaste de las piezas dentarias. / In recent years, the trend in restorative dentistry is the maximum conservation of the remaining dental tissues, and this being so, what are sought are different alternatives to be able to rehabilitate the loss of parts in patients who come to the consultation. The hybrid adhesive prostheses combine a conventional fixed prosthesis (crowns) with minimal wear attachments (veneers). We present a clinical case of a 43-year-old male patient who attended the clinic of the Peruvian University of Applied Sciences (UPC) in 2018 for presenting a radicular crown fracture of an upper central incisor, a pillar of a fixed partial prosthesis that it caused the mobility of the prosthesis and altered the aesthetics. We planned a hybrid prosthesis that combined a metal-free ceramic crown in the central incisor and ceramic veneers (buccal and palatal) in the lateral incisor. The clinical case evidenced an improvement in aesthetics, preserved dental tissues and improved patient satisfaction with respect to his smile. The combination of a conventional metal-free prosthesis and ceramic veneers is an efficient alternative for the management of upper partial anterior edentulism with minimal wear of the teeth. / Trabajo académico

A perda óssea progressiva ao redor da plataforma dos implantes dentários é um desafio a ser vencido na clínica, uma vez que, interfere na manutenção e controle dos tecidos peri-implantares e pode afetar a estética. Esta pesquisa teve como objetivo avaliar a concentração de tensões ao redor de diferentes implantes dentários, variando a macrogeometria, conexão protética e profundidade da inserção da plataforma protética, sob carregamento axial ou oblíquo. Foram criados três modelos de resina fotoelástica para cada tipo de implante avaliado (hexágono externo, hexágono externo wedge, hexágono interno e cone Morse). Cada corpo de prova se diferenciou pelo posicionamento da plataforma do implante em relação à margem superior do bloco, em três posições diferentes: I - plataforma posicionada 2mm abaixo da margem do bloco; II - plataforma posicionada no mesmo nível da margem do bloco; III - plataforma posicionada 2mm acima da margem do bloco. Foi aplicada uma força de 100N através de um dispositivo instalado sobre pilares retos e angulados, simulando um carregamento axial e oblíquo respectivamente. Um total de 4 pontos foram avaliados de um lado do implante. Dados quantitativos foram coletados e utilizados para análise estatística. A regressão linear múltipla mostrou relação entre a distribuição das tensões com relação à profundidade de inserção independentemente do tipo de conexão protética ou do carregamento oclusal. O grupo I (2mm abaixo da margem) foi o que apresentou os menores valores (p<0.05) de tensão quando comparado com os outros grupos (II e III). De acordo com as limitações deste estudo pode-se concluir que a macrogeometria, profundidade de inserção da plataforma e tipo de carregamento oclusal influenciam no comportamento da distribuição das tensões ao redor dos implantes. Em relação à conexão protética, os resultados mostraram padrões de franjas semelhantes independentemente do tipo de conexão / The progressive bone loss at the neck of dental implant is a clinical concern since it affects the maintenance of dental esthetics. The stress concentration, the connection type and the microgap appear to be factors that cause alterations at the marginal bone level. The aim of this research was to evaluate the stress concentration around different dental implants, varying the macrogeometry, prosthetic connection and depth of the insertion of the prosthetic platform, under axial or oblique loading. Three blocks of photoelastic resin for each type of implant connection (external hexagon, external hexagon flattened, internal hexagon and Morse taper) were built. Each block differed in the position of the implant platform in relative to the upper margin of the block: I (2mm below), II (at the same level) and III (2mm above). A force of 100N was applied to both a straight and tilted abutments. A multiple linear regression showed the relation between the stress distribution and the insertion depth. For all the implant types, both with straight and tilted abutments, Group I presented the lowest stress concentration around the fixture when compared to group II and III (p<0,05). According to the limitations of this study it could be concluded that the macrogeometry, depth of insertion of the platform and type of occlusal loading influence the behavior of the distribution of stresses around the implants. Regarding the prosthetic connection, the results showed similar patterns of fringes regardless of the type of connection

O presente estudo avaliou a intercambiabilidade dos componentes protéticos de implantes de hexágono externo medindo-se a precisão da interface implante/pilar (I/P) com microscopia eletrônica de varredura. Foram utilizados dez implantes para cada uma de três marcas (SIN, Conexão, Neodent) com seus respectivos pilares (base metálica de CoCr , rotacional e não rotacional) e um de marca alternativa (Microplant) em um arranjo com todas as combinações de I/P possíveis. O valor de referência para a intercambiabilidade das várias marcas de componentes foi definido pela diferença do pilar original para com seu respectivo implante. Dessa maneira, a intercambiabilidade foi considerada válida quando o resultado para um determinado pilar colocado sobre um implante fosse igual ou menor que a diferença medida, quando o pilar da mesma marca do implante foi posicionado. Um grau de desajuste foi observado em todos os espécimes. De uma maneira geral, o pilar antirrotacional foi mais preciso do que o rotacional. Estes variaram de 0,6 16,9m, com mediana 4,6m, enquanto o antirrotacional foi de 0,3 12,9m, com mediana de 3,4m. Os espécimes com o pilar e o implante Conexão tiveram uma diferença maior que o conjunto original para SIN e NEO (p<0,05). Apesar de estes últimos apresentarem resultados semelhantes com seus respectivos pilares, quando trocados, não mantiveram a mesma precisão original. Os resultados sugerem que a marca alternativa seria a única que apresentaria compatibilidade com todos os sistemas, enquanto as outras marcas não seriam completamente intercambiáveis. / The present study evaluated the interchangeability of prosthetic components for external hexagon implants by measuring the precision of the implant/abutment (I/A) interface using scanning electron microscopy. Ten implants for each of three brands (SIN, Conexão, Neodent) were tested with their respective abutments (milled CoCr collar rotational and non-rotational) and that of an alternative manufacturer (Microplant) in randomly arranged I/A combinations. The degree of interchangeability between the various brands of components was defined using the original abutment interface gap with its respective implant as the benchmark dimension. Accordingly, when the result for a given component placed on an implant was equal to or smaller then that gap measured when the component of the same brand as the implant was positioned, interchangeability was considered valid. Some degree of maladjustment was observed on all specimens. Generally, the non-rotational component was more accurate than its rotational counterpart. The latter samples ranged from 0.6 16.9m, with a median of 4.6m; the former from 0.3 12.9m, with a median of 3.4m. Specimens with the abutment and fixture from Conexão had larger microgap than the original set for Sin and Neodent (p<0.05). Even though the latter systems had similar results with their respective components, their interchanged abutments did not reproduce the original accuracy. The results suggest that the alternative brand abutment would have compatibility with all systems while the other brands were not completely interchangeable.

O presente estudo avaliou a intercambiabilidade dos componentes protéticos de implantes de hexágono externo medindo-se a precisão da interface implante/pilar (I/P) com microscopia eletrônica de varredura. Foram utilizados dez implantes para cada uma de três marcas (SIN, Conexão, Neodent) com seus respectivos pilares (base metálica de CoCr , rotacional e não rotacional) e um de marca alternativa (Microplant) em um arranjo com todas as combinações de I/P possíveis. O valor de referência para a intercambiabilidade das várias marcas de componentes foi definido pela diferença do pilar original para com seu respectivo implante. Dessa maneira, a intercambiabilidade foi considerada válida quando o resultado para um determinado pilar colocado sobre um implante fosse igual ou menor que a diferença medida, quando o pilar da mesma marca do implante foi posicionado. Um grau de desajuste foi observado em todos os espécimes. De uma maneira geral, o pilar antirrotacional foi mais preciso do que o rotacional. Estes variaram de 0,6 16,9m, com mediana 4,6m, enquanto o antirrotacional foi de 0,3 12,9m, com mediana de 3,4m. Os espécimes com o pilar e o implante Conexão tiveram uma diferença maior que o conjunto original para SIN e NEO (p<0,05). Apesar de estes últimos apresentarem resultados semelhantes com seus respectivos pilares, quando trocados, não mantiveram a mesma precisão original. Os resultados sugerem que a marca alternativa seria a única que apresentaria compatibilidade com todos os sistemas, enquanto as outras marcas não seriam completamente intercambiáveis. / The present study evaluated the interchangeability of prosthetic components for external hexagon implants by measuring the precision of the implant/abutment (I/A) interface using scanning electron microscopy. Ten implants for each of three brands (SIN, Conexão, Neodent) were tested with their respective abutments (milled CoCr collar rotational and non-rotational) and that of an alternative manufacturer (Microplant) in randomly arranged I/A combinations. The degree of interchangeability between the various brands of components was defined using the original abutment interface gap with its respective implant as the benchmark dimension. Accordingly, when the result for a given component placed on an implant was equal to or smaller then that gap measured when the component of the same brand as the implant was positioned, interchangeability was considered valid. Some degree of maladjustment was observed on all specimens. Generally, the non-rotational component was more accurate than its rotational counterpart. The latter samples ranged from 0.6 16.9m, with a median of 4.6m; the former from 0.3 12.9m, with a median of 3.4m. Specimens with the abutment and fixture from Conexão had larger microgap than the original set for Sin and Neodent (p<0.05). Even though the latter systems had similar results with their respective components, their interchanged abutments did not reproduce the original accuracy. The results suggest that the alternative brand abutment would have compatibility with all systems while the other brands were not completely interchangeable.

Indiana University-Purdue University Indianapolis (IUPUI) / Background: New glass ceramics and Computer-Aided Design/Computer Assisted Manufacture (CAD/CAM) have become common aspects of modern dentistry. The use of posterior ceramic crowns with a high level of esthetics, fabricated using the CAD/CAM technology is a current treatment modality. Several materials have been used to fabricate these crowns, including lithium disilicate glass-ceramics, which have not been fully investigated in the literature. Objective: to investigate the load to fracture of lithium disilicate glass ceramic posterior crowns fabricated by CAD/CAM technology with different material thicknesses adhesively cemented on epoxy resin. Methods: Four groups of different ceramic thicknesses (0.5 mm, 1 mm, 1.5 mm, and 2 mm) were fabricated by milling CAD/CAM lithium disilicate IPS emax CAD blocks. A total of 68 posterior crowns were surface treated and luted with a resin adhesive cement on an epoxy resin model. Samples were fatigued then loaded to fracture using a universal testing machine to test the fracture strength. Statistical comparisons between various crown thicknesses were performed using one-way ANOVA followed by Fisher's Protected Least Significant Differences. Results: There was a significant difference in the load-to-fracture (N) value for all comparisons of the four thickness groups (p < 0.0001), except 2 mm vs. 1.5 mm (p = 0.325). The mean load-to-fracture (N) was significantly higher for 2 mm than for 1 mm or 0.5 mm. Additionally, the mean load-to-fracture was significantly higher for 1.5 mm than for 1 mm or 0.5 mm. Furthermore, the mean load-to-fracture was significantly higher for 1 mm than for 0.5 mm. Conclusion: Within the limitation of this study, it is advisable for clinical applications to consider a crown thickness of 1.5 mm or greater of milled lithium disilicate for posterior single teeth.

Indiana University-Purdue University Indianapolis (IUPUI) / The objective of this study was to evaluate the in vivo performance of the novel press-fit dental implant fabricated via electron beam melting (EBM, Southern Methodist Univ.) and compare it to a commercially-available porous-coated press-fit dental implant (Endopore, Innova Corp.). Twelve cylindrical shaped implants 3 mm in diameter x 5 mm long were made by EBM (Southern Methodist Univ.) using Ti6Al4V ELI alloy. Twelve commercial implants (Endopore, Innova Corp.) of the same geometry were used as controls. Samples were implanted in rabbit tibia and retrieved six weeks postoperatively. Six specimens from each implant type were embedded undecalcified, sectioned, and stained with toluidine blue (Sigma) for histomorphometry analysis. Bone-to-implant contact (BIC) was measured. On the six remaining samples from each implant type, the mechanical properties were evaluated by pushout test on a material testing machine. The samples were loaded at a loading rate of 1 mm/min. The pushout strength was measured and the apparent shear stiffness was calculated. The results were analyzed with a paired-t test. The histology shows osteointegration of surrounding bone with both implant types. Bone was found to grow into the porous space between the beads. Both the Endopore (Innova Corp.) and the EBM (Southern Methodist Univ.) showed similar BIC. The mean BIC for the Endopore (Innova Corp.) and EBM (Southern Methodist Univ.) implant were 35 ± 6% and 32 ± 9%, respectively. It failed to reach statistical significance (p > 0.05). The peak pushout force for Endopore (Innova Corp.) and EBM (Southern Methodist Univ.) implants were 198.80 ± 61.29 N and 243.21 ± 69.75 N, respectively. The apparent shear stiffness between bone and implant for the Endopore (Innova Corp.) and EBM (Southern Methodist Univ.) implants were 577.36 ± 129.99 N/mm; and 584.48 ± 146.63 N/mm, respectively. Neither the peak pushout force nor the apparent shear stiffness of the implants was statistically different between the two groups (p > 0.05). The results suggest that the implants manufactured by EBM (Southern Methodist Univ.) perform equally well as the commercial implant Endopore (Innova Corp.) in this current animal model.