Marginal gap of zirconia and lithium disilicate frameworks produced by the CAD-CAM technique through a comparator microscope ­ in vitro analysis / Fenda marginal de estruturas de zircônia e dissilicato de lítio produzidas pela técnica CAD-CAM através de um microscópio comparador ­ análise in vitro

Objective: The aim of this study was to evaluate the marginal gap of frameworks produced using the CAD-CAM system, from zirconia and lithium disilicate blocks, adapted to a tooth preparation and a gypsum die. Material and Methods: For this study, a human first molar tooth was used as a master model with a full crown preparation. It was molded 20 times to obtain the gypsum die and randomly divided into 2 groups (n=10) for the fabrication of zirconia and lithium disilicate frameworks. The frameworks were made using pre-sintered zirconia blocks and lithium disilicate blocks, both CAD-CAM systems. The marginal gap was measured in µm at four points (buccal, palatal, mesial, and distal) using a comparator microscope with 30x magnification, with the framework seated on the master model (tooth), and on the gypsum die. Marginal gap data (µm) were evaluated using two-way analysis of variance and Tukey's test with a significance level of 5%. Results: The results showed that there was no statistically significant interaction between the factors studied (p=0.223) or isolated factors (ceramic factor p=0.886 and die factor p=0.786). Conclusion: Both ceramics produced using the CAD-CAM technique did not exhibit statistical differences in marginal adaptation on the two types of substrates, both on tooth preparation and on the gypsum die (AU)

Objetivo: O objetivo deste estudo foi avaliar o espaço marginal de estruturas produzidas usando o sistema CAD-CAM, a partir de blocos de zircônia e dissilicato de lítio, adaptadas a um preparo sobre dente e a um troquel de gesso. Material e Métodos: Para este estudo, um dente molar humano foi utilizado como modelo mestre com preparo para coroa total. Este foi moldado 20 vezes para obter o troquel de gesso e dividido aleatoriamente em 2 grupos (n=10) para a fabricação de estruturas de zircônia e dissilicato de lítio. As estruturas foram feitas usando blocos de zircônia pré-sinterizados e blocos de dissilicato de lítio, ambos sistemas para CAD-CAM. O espaço marginal foi medido em µm, em quatro pontos (bucal, palatal, mesial e distal), utilizando um microscópio comparador com ×30 de ampliação e com a estrutura assentada no modelo mestre (dente) e no troquel de gesso. Os dados de espaço marginal (µm) foram avaliados usando análise de variância bidirecional e teste de Tukey com um nível de significância de 5%. Resultados: Os resultados mostraram que não houve interação estatisticamente significativa entre os fatores estudados (p=0,223) ou isoladamente (fator cerâmica p=0,886 e fator troquel p=0,786). Conclusão: Ambas as cerâmicas produzidas usando a técnica CAD-CAM não apresentaram diferenças estatísticas em relação à adaptação marginal nos dois tipos de substratos, tanto na preparação dentária quanto no troquel de gesso(AU)

Is scanning under rubber dam isolation a feasible approach for the execution of indirect restorations? / O escaneamento sob isolamento absoluto é uma técnica viável para execução de restaurações indiretas?

Objective: The aim of the study was to report the aplicability of intraoral scanning while rubber dam isolation is in place. Material and Methods: Female patient, 50 years old, required restorative procedures on teeth 35 and 37. An intraoral scan was initially performed on both arches. Isolation was carried out from 33 to 37, tooth preparation and immediate dentin sealing were carried out. A new scan with the rubber dam in place was performed and a CAD/CAM lithium disilicate hybrid block was digitally designed, milled, crystallized and cemented under the tooth surface with the rubber dam still in position. After completing this stage, the rubber dam was removed, the occlusion was verified, presenting excellent aesthetic and functional results. Results: The absolute isolation process used in the present study works as an excellent device for gingival retraction. Conclusion: The absolute isolation can be recommended in clinical activities of intraoral scanning favoring the quality of the final result of treatments (AU)

Objetivo: O objetivo do estudo foi relatar a aplicabilidade do escaneamento intraoral sob isolamento absoluto. Material e Métodos: Paciente do sexo feminino, 50 anos, necessitou de procedimentos restauradores nos dentes 35 e 37. Uma varredura intraoral foi inicialmente realizada em ambos os arcos. O isolamento absoluto foi feito de 33 a 37, permitindo a realização do preparo dentário e selamento imediato da dentina. Um novo escaneamento com o dique de borracha colocado foi realizado e um bloco híbrido de dissilicato de lítio CAD/CAM foi projetado digitalmente, fresado, cristalizado e cimentado sob a superfície dentária ainda com o dique de borracha em posição. Após a finalização dessa etapa, o dique de borracha foi removido, a oclusão foi verificada apresentando ótimos resultados estéticos e funcionais. Resultados: O isolamento absoluto utilizado no presente estudo funciona como um excelente dispositivo para retração gengival. Conclusão: O isolamento absoluto pode ser recomendado em atividades clínicas de escaneamento intraoral favorecendo a qualidade do resultado final dos tratamentos (AU)

Digital repair for a patient with limited mouth opening: a case report and literature review / 口腔疾病防治

Objective@#To explore an accurate method to obtain an intraoral model of patients with specific limited mouth opening (microstomia) due to systemic scleroderma.@*Methods@#This study followed medical ethics, and informed consent has been obtained from patients. A case of Ken's Type I mandibular dentition defect scleroderma with limited mouth opening was addressed with digital technology as the leading method combined with the traditional impression method of segmental impression. Individual trays were made based on the patient's left and right mandibular dentition, and segmented molds were obtained. Simultaneously, intraoral scanning was performed to obtain the morphological data of both the soft and hard tissues of the upper and lower mandibles. After each part of the model was obtained, the mandibular model was scanned and digitally aligned to form the final denture model, and the final removable partial denture was designed and made by computer aided design/computer aided manufacturing (CAD/CAM) technology. At the same time, combined with the literature, the diagnosis and treatment of removable partial denture in patients with limited mouth opening were retrospectively analyzed.@*Results@#The denture was well retained and achieved a good repair effect. The patients expressed satisfaction with the mastication efficiency and other functions of the denture. The findings of the literature review show that the integration of digital technology with the traditional impression method, along with computer fitting, can accurately obtain the patient's oral model and facilitate successful follow-up repairs. However, when the anterior mandibular dentition of the patient is absent, the margin of error is increased in this procedure, which deserves further exploration.@*Conclusion@#Utilizing digital technology as the leading method, combined with the traditional impression method of segmental impression, for the repair of dental defects in patients with limited mouth opening, has proven to be effective. Thus, patients report a positive medical experience with high satisfaction, indicating that this approach is worthy of clinical promotion.

Aumento do Rebordo Alveolar com Enxerto em Bloco Impresso Personalizado: Relato de Caso / Alveolar ridge augmentation with custom 3D-printed block graft: Case report

A utilização da tecnologia CAD/CAM (computer aided design/computer aided manufacturing) e 3D (tridimensional) para reconstruções alveolares na implantodontia permite o planejamento pré-operatório detalhado, o design do resultado desejado do enxerto e a avaliação virtual do resultado em relação à reconstrução protética. Este trabalho objetiva detalhar a técnica cirúrgica de enxerto ósseo sintético confeccionado por meio dessa tecnologia, seguido da instalação de implantes osseointegráveis e reabilitação protética em um defeito ósseo na mandíbula. Paciente masculino, 22 anos, compareceu à clínica por avulsão dos elementos 32, 31, 41 e 42 com significativa perda óssea vertical de rebordo alveolar. Devido à extensa perda óssea, realizou-se enxerto em bloco prototipado impresso. O escaneamento intraoral e os arquivos de imagem gerados foram enviados ao centro de planejamento virtual. Primeiramente, foi realizada a cirurgia para instalação do enxerto em bloco. Após o período de cicatrização, foi realizada cirurgia para instalação de dois implantes osseointegráveis. Esperado o período de três meses a partir da instalação dos implantes, foi realizada a confecção de próteses provisórias fixas sobre implantes a fim de realizar o condicionamento dos tecidos moles peri-implantares e o carregamento progressivo dos implantes. O aumento do rebordo alveolar através do uso de enxerto em bloco impresso personalizado apresentou-se como uma técnica com inúmeras vantagens, por não necessitar de sítio doador, reduzir tempo cirúrgico e apresentar perfeita adaptação do bloco ao defeito ósseo, resultando em menor morbidade pós-operatória. Essa técnica é uma indicação para casos de defeitos ósseos severos, visando a otimizar o resultado e a propiciar menor desconforto ao paciente.

The use of the technology CAD/CAM (computer aided design/computer aided manufacturing) and 3D (three dimensional) to alveolar reconstructions in implant dentistry allows detailed preoperative planning, the design of the desired grafting result, and the virtual evaluation of the result in relation to the prosthetic reconstruction. This paper aims to details the synthetic bone graft made through this technology, followed by the installation of osseointegrated implants and prosthetic rehabilitation in a bone imperfection in the jaw. A 22-year-old man attended the clinic due to a tooth avulsion of the four lower incisors with significant vertical bone loss of alveolar ridge. Because of the extensive bone loss, it was made a prototyped printed block graft. The intraoral scan and the generated image files were sent to the virtual planning center. First, it was necessary a surgery to install the block graft. After the healing process, it was made a surgery to put two osseointegrated implants. Three months later, temporary fixed prostheses on implants were made to conditioning the peri-implant soft tissues and the progressive loading of the implants. The increase of the alveolar ridge using personalized printed block graft was presented as a technique with numerous advantages, since it does not require a donor site, reduces the surgical time and presents perfect adaptation of the block to the bone imperfection, resulting in a less postoperative morbidity. This technique is indicated to cases of severe bone imperfections, aims to optimize results, and provide less discomfort to the patient.

Adaptación marginal e interna de cofias fabricadas por métodos convencionales, CAD/CAM de fresado y sinterizado por láser / Marginal and internal adaptation of copings manufactured by conventional methods, CAD/CAM milling and laser sintering

Introducción: la adaptación marginal e interna de nuestras restauraciones fabricadas por fundición sistemas de fresado y sinterización láser es uno de los factores clínicos más importantes para el éxito de las prótesis fijas, previniendo el riesgo de microfiltración y enfermedad periodontal. Objetivo: evaluar la adaptación marginal e interna de cofias metálicas en aleación Cr-Co confeccionadas por técnicas convencionales, CAD/ CAM de fresado y sinterizado por láser. Material y métodos: estudio de tipo experimental, comparativo e in vitro. Se imprimió un modelo maestro en Cr-Co, proveniente del escaneo de un premolar preparado para corona completa, sobre el cual se diseñaron 30 cofias divididas en tres grupos: el primero que corresponde al grupo cofias fundidas fresadas en disco de cera A (A = 10), el segundo grupo cofias fresadas en disco de metal presinterizado B (B = 10) y el tercer grupo cofias impresas por sinterización láser C (C = 10). Se empleó la réplica de silicona, colocando silicona al interior de cada cofia, sobre el modelo maestro, simulando al cemento, mediante una máquina de ensayo universal se realizó una compresión de 50 N. Luego de retirar cada cofia se rellenaron con silicona pesada de adición, obteniendo una réplica de silicona. Se efectuaron dos cortes transversales en sentido vestíbulolingual y mesiodistal. Se observó el espesor de silicona VPS (vinil poliéter silicona) mediante un estereomicroscopio (Nikon SMZ745T), obteniendo valores en micrómetros. Para el análisis estadístico se utilizó el software SPSS 25 con el fin de realizar la prueba de normalidad y ANOVA de dos vías bajo un nivel de confianza del 95%. Resultados: el menor gap lo obtuvo el grupo de fresadas, seguido de las impresas y por último las fundidas por métodos convencionales. ANOVA de dos vías reveló diferencias estadísticamente significativas entre los tres grupos (p < 0.0001). Conclusiones: se encontró que el gap varía con cada método de fabricación, la técnica convencional de fundido mostró un mayor gap, ninguna excediendo el rango clínicamente aceptable (AU)

Introduction: the marginal and internal adaptation of our restorations manufactured by casting, milling systems and laser sintering is one of the most important clinical factors for the success of fixed prostheses, preventing the risk of microleakage and periodontal disease. Objective: evaluate the marginal and internal adaptation of metal copings in Cr-Co alloy made by conventional techniques, CAD/CAM milling and laser sintering. Material and methods: an experimental, comparative and in vitro study, a Cr-Co master model was printed from the scan of a premolar prepared for a full crown. An experimental, comparative and in vitro study, a Cr-Co master model was printed from the scan of a premolar prepared for a full crown, on which 30 caps divided into three groups were designed; the first group corresponds to the cast copings milled on a wax disc A (A = 10), the second group milled copings on a presintered metal disc B (B = 10) and the third group printed by laser sintering copings C (C = 10). The silicone replica was used, placing silicone inside each coping, on the master model, simulating cement, using a universal testing machine, a 50 N compression was performed. After removing each coping, they were filled with heavy addition silicone, obtaining a silicone replica. Two cross-sections were made in the buccolingual and mesiodistal direction., observing the thickness of the VPS (vinyl polyeter silicone) silicone using a stereomicroscope (Nikon SMZ745T), obtaining values in micrometers. For the statistical analysis, the SPSS 25 software was used in order to perform the normality and two-way ANOVA tests under a 95% confidence level. Results: the smallest gap was obtained by the milled group, followed by the printed ones and finally those cast by conventional methods. Two-way ANOVA revealed statistically significant differences between the three groups (p < 0.0001). Conclusions: the gap was found to vary with each fabrication method, the conventional casting technique showed a larger gap, none exceeding the clinically acceptable range (AU)

Influence of different surface treatments on bond strength of a Self-Adhesive resin cement to CAD-CAM materials / Influencia de los diferentes tratamientos superficiales en la unión del cemento resinoso autoadhesivo a los materiales CAD-CAM

To evaluate the shear bond strength (SBS) of self-adhesive resin cement when used with two different computer-aided design (CAD)-computer-aided manufacturing (CAM) materials after various surface treatments. Nanoceramic resin Lava Ultimate (LU) and feldspathic ceramic Vita Mark II (VM) CAD-CAM block samples were prepared with 1.5-mm thickness, and a total of 90 samples were obtained (N=90), with five samples of each block. The samples were divided into the following five groups according to the surface treatments (n=9): group 1, untreated (control); group 2,5% hydrofluoric acid etching; group 3, Er: YAG laser irradiation; group 4, tribochemical silica coating (Cojet); and group 5, air-abrasion with Al2O3. After silane application, resin cement was applied on a transparent matrix (diameter, 3mm; height, 2mm) on the blocks. SBS was determined using a universal testing device at a crosshead speed of 1mm/min. Two-way analysis of variance (ANOVA) and Tukey's post hoc tests were used to analyze the SBS values. LU showed the highest SBS value in group 4. The average SBS values in groups 3 and were found to be lower than that in the control group (p<0.05). When VM was examined, while all surface treatments increased the SBS values significantly, the highest SBS value was observed in group 4 (p<0.05). This study revealed that all surface treatments used negatively affected the bond strength values of self-adhesive resin cement to LU, except for Cojet application. The SBS values of resin cement with VM increased in all surface treatment application groups.

Evaluar la resistencia de unión al corte (SBS) del cemento de resina autoadhesivo cuando se utiliza con dos materiales diferentes de diseño asistido por computadora (CAD) y fabricación asistida por computadora (CAM) después de varios tratamientos superficiales. Se prepararon muestras de bloques CAD-CAM de resina Lava Ultimate (LU) y cerámica feldespática Vita Mark II (VM) con un espesor de 1,5mm, y se obtuvieron un total de 90 muestras (N=90), con cinco muestras de cada bloque. Las muestras se dividieron en los siguientes cinco grupos según los tratamientos superficiales (n=9): grupo 1, sin tratar (control); grupo 2, grabado con ácido fluorhídrico al 5%; grupo 3, irradiación con láser Er: YAG; grupo 4, recubrimiento triboquímico de sílice (Cojet); y grupo 5, aire-abrasión con Al2O3. Después de la aplicación de silano, se aplicó cemento de resina sobre una matriz transparente (diámetro, 3mm; altura, 2mm) sobre los bloques. La SBS se determinó usando un dispositivo de prueba universal a una velocidad de cruceta de 1mm/min. Se utilizaron análisis de varianza bidireccional (ANOVA) y pruebas post hoc de Tukey para analizar los valores de SBS. LU mostró el valor más alto de SBS en el grupo 4. Los valores promedio de SBS en los grupos 3 y fueron más bajos que en el grupo de control (p<0,05). Cuando se examinó VM, mientras que todos los tratamientos superficiales aumentaron significativamente los valores de SBS, el valor más alto de SBS se observó en el grupo 4 (p<0,05). Este estudio reveló que todos los tratamientos de superficie utilizados afectaron negativamente los valores de resistencia de la unión del cemento de resina autoadhesivo a LU, a excepción de la aplicación Cojet. Los valores de SBS del cemento de resina con VM aumentaron en todos los grupos de aplicación de tratamiento de superficie.

Effect of Aging and Thermocycling on Flexural Strength of PEEK as a Provisional Restoration for Full Mouth Rehabilitation – An In vitro Study

Introduction: To compare the flexural strength of autopolymerizing poly methyl methacrylate resins (PMMA) resin, CAD/CAM milled PMMA and CAD/CAM milled poly ether ether ketone (PEEK) when used as provisional restorative materials for long span situations in full mouth rehabilitation after aging and thermocycling. Materials and Methods: Sixty samples (25 mm × 2 mm × 2 mm) were fabricated using autopolymerizing PMMA resin (GROUP I), CAD/CAM milled PMMA (GROUP II) and PEEK (GROUP III). The groups were subdivided into A and B and subjected to 7 days of aging and 500 cycles of thermocycling (subgroup A) and 14 days of aging and 1000 cycles of thermocycling (subgroup B), respectively, and flexural strength was evaluated using a three?point bend test. The data were analyzed with student t test and pair?wise comparison of mean values was done by ANOVA. Results: The flexural strength of PEEK subjected to 7 days of aging and 500 cycles of thermocycling (III (A) ? 6628.70 MPa) was the highest among all groups followed by PEEK subjected to 14 days of aging and 1000 cycles of thermocycling (III (B) ? 3760.50 MPa). Conclusion: The mean flexural strength of PEEK was statistically significant than the other two materials tested and hence can be recommended for use as a provisional restorative material for long span situations in full mouth rehabilitation. However, the mean flexural strength of PEEK reduced approximately by 44% when subjected to further aging

Estabilidade de cor de diferentes sistemas cerâmicos fresados no CAD/CAM e polidos com diferentes métodos / Color stability of different ceramic systems milled in CAD/CAM and polished with different methods

A descoloração ou perda de translucidez dos materiais cerâmicos usados em odontologia ainda hoje é um problema, especialmente pelo comprometimento estético. Com o objetivo de comparar a estabilidade de cor, blocos de dissilicato de lítio (IPS e.max CAD HT) e de silicato de lítio reforçado com zircônia (Vita Suprinity HT) fresados no desenho de um disco com dimensões de 1,5 × 7 × 12 mm3 (n = 120) foram preparados usando 3 procedimentos de acabamento de superfície: glaze, polimento mecânico e coloração externa e glaze. Em seguida, cada grupo foi dividido em 2 subgrupos de armazenamento, chá preto e café (n = 10/grupo). As mensurações de cor foram medidas com espectrofotômetro (VITA Easyshade) no estágio inicial e após 1 semana, 2 semanas, 1 mês, 2 meses de armazenamento. As alterações de cor (ΔE) foram calculadas e analisadas estatisticamente usando ANOVA (α < 0,05). Observamos que, para ambos os materiais cerâmicos, o procedimento de glaze apresentou valores de mudança de cor estatisticamente menores do que os outros grupos (p < 0,05) após o armazenamento em ambas as bebidas. Os grupos de dissilicato de lítio apresentaram valores de alteração de cor estatisticamente menores em relação aos grupos de silicato de lítio reforçados com zircônia. Conclui-se que, o glaze sozinho levou a uma maior estabilidade de cor em relação ao polimento mecânico e coloração externa o dissilicato de lítio apresentou maior estabilidade de cor em comparação com o silicato de lítio reforçada com zircônia.

The discoloration or loss of translucency of ceramic materials used in dentistry is still a problem today, especially due to aesthetic compromise. In order to compare color stability, lithium disilicate (IPS e.max CAD HT) and zirconia-reinforced lithium silicate (Vita Suprinity HT) blocks were milled into a disc design with dimensions of 1.5 × 7 × 12 mm3 (n = 120). The specimens were prepared using 3 surface finishing procedures: glaze, mechanical polishing and external staining and glaze. Then, each group was divided into 2 storage subgroups, black tea and coffee (n = 10/group). Color measurements were measured with a spectrophotometer (VITA Easyshade) at the initial stage and after 1 week, 2 weeks, 1 month, 2 months of storage. Color changes (ΔE) were calculated and statistically analyzed using ANOVA (α < 0.05). We observed that, for both ceramic materials, the glaze procedure presented statistically lower color change values ​​than the other groups (p < 0.05) after storage in both beverages. The lithium disilicate groups showed statistically lower color change values ​​than the zirconia-reinforced lithium silicate groups. It is concluded that, glaze alone led to greater color stability compared to mechanical polishing and external staining, lithium disilicate showed greater color stability compared to zirconia-reinforced lithium silicate.

Restaurações endocrown em pré-molares: influência das paredes remanescentes da estrutura dentária e materiais restauradores na resistência à fadiga / Endocrown restorations in premolars: influence of remaining axial walls of tooth structure and restorative materials on fatigue resistance

Este estudo teve como objetivo avaliar o efeito da estrutura dentária remanescente e dois materiais diferentes de restauração CAD/CAM no desempenho à fadiga e no modo de falha de pré-molares tratados endodonticamente restaurados por endocrowns. Um total de 90 pré-molares superiores foram tratados endodonticamente e divididos aleatoriamente de acordo com o número de paredes axiais remanescentes, e os materiais restauradores foram divididos em 6 grupos (n = 15); quatro paredes restantes restauradas com zircônia ultratranslúcida 5Y-PSZ (grupo Fo-Z) e dissilicato de lítio (grupo Fo-L), três paredes restantes restauradas com 5Y-PSZ (grupo Th-Z) e dissilicato de lítio (grupo Th-L) e duas paredes restantes restauradas com 5YPSZ (grupo Tw-Z) e dissilicato de lítio (Tw-L). As restaurações foram cimentadas adesivamente e os espécimes foram submetidos a cargas de fadiga gradual em seu longo eixo (carga inicial: 200 N, frequência: 20 Hz). Uma carga incremental de 100 N por 10.000 ciclos foi aplicada com um pistão metálico de Ø 6 mm até a falha. A carga de falha por fadiga (FFL) e o número de ciclos de falha (CFF) no momento da falha foram registrados e analisados estatisticamente por ANOVA 2 fatores e teste de Kaplan-Meier (α = 0,05). Os espécimes fraturados foram examinados em estereomicroscópio em 8× e 25× e os modos de falha foram determinados como reparáveis ou catastróficos. FFL e CFF foram significativamente influenciados pelo material restaurador (p < 0,05). As restaurações de 5Y-PSZ apresentaram FFL (Fo-Z = 1487 N, Tw-Z = 1427 N, Tw-Z = 1533 N) e probabilidade de sobrevivência significativamente maiores quando comparadas com dissilicato de lítio (Fo-L = 1060 N, Th-L = 940 N, TwL = 1000 N). O número de paredes remanescentes não afetou o comportamento de fadiga ou modo de falha dos corpos de prova. Das restaurações de dissilicato de lítio, 51% tiveram falhas reparáveis, enquanto 95% das restaurações de zircônia ultratranslúcida 5Y-ZP tiveram falhas catastróficas. Endocrowns de zircônia apresentaram melhor desempenho em fadiga do que endocrowns de dissilicato de lítio, independentemente do número de paredes remanescentes do eixo. Endocrowns de pré-molares de dissilicato de lítio e 5Y-PSZ apresentaram maior FFL do que as cargas mastigatórias normais (AU)

This study aimed to evaluate the effect of the remaining tooth structure and two different CAD/CAM restoration materials on the fatigue performance and failure mode of endodontically treated premolars restored with endocrowns. A total of 90 maxillary premolars were endodontically treated and divided randomly according to the number of remaining axial walls, and the restorative materials were divided into 6 groups (n = 15); four remaining walls restored with ultratranslucent zirconia 5Y-PSZ (group Fo-Z) and lithium disilicate (group Fo-L), three remaining walls restored with 5Y-PSZ (group Th-Z) and lithium disilicate (Group Th-L), and two remaining walls restored with 5Y-PSZ (group Tw-Z) and lithium disilicate (Tw-L). The restorations were cemented adhesively and the specimens were subjected to stepwise fatigue loading along the long axis (initial load: 200 N, frequency: 20 Hz). An incremental step load of 100 N per 10,000 cycles was applied with a Ø6-mm metallic piston until failure. The fatigue failure load (FFL) and number of failure cycles (CFF) at the time of failure were recorded and statistically analyzed with two-way ANOVA and the Kaplan-Meier test (α = 0.05). Fractured specimens were examined under a stereomicroscope at 8× and 25× and failure modes determined as reparable or catastrophic. FFL and CFF were significantly influenced by restorative material (p < 0.05). 5Y-PSZ endocrowns showed significantly higher FFL (Fo-Z = 1487 N, Th-Z = 1427 N, Tw-Z = 1533 N) and survival probability when compared with lithium disilicate (Fo-L = 1060 N, Th-L = 940 N, Tw-L = 1000 N). The number of remaining walls did not affect the fatigue behavior or failure mode of the specimens. Of the lithium disilicate restorations, 51% had repairable failures, while 95% of ultratranslucent zirconia 5Y-ZP restorations had catastrophic failures. Zirconia endocrowns showed better fatigue performance than lithium disilicate endocrowns, regardless of the number of remaining axis walls. Lithium disilicate and 5Y-PSZ premolar endocrowns showed higher FFL than the normal masticatory loads (AU)

The Effect of Immediate Dentin Sealing on the Marginal Adaptation of LithiumDisilicate Overlay Restorations using different types of luting agents / Efeito do selamento imediato da dentina na adaptação marginal de restaurações overlay de dissilicato de lítio utilizando diferentes tipos de agentes de cimentação: estudo in vitro

Objective:This study evaluated the effect of immediate dentin sealing on the marginal adaptation of lithium disilicate overlays with three different types of resin-luting agents: preheated composite, dual-cure adhesive resin, and flowable composite. Materials and Methods: Forty-eight maxillary first premolars of similar size were prepared with a butt joint preparation design. The teeth were separated into two primary groups, each with twenty-four teeth: Group DDS: Delay dentin sealing (non-IDS) teeth were not treated. Group IDS: dentin sealing was applied immediately after teeth preparation. Each group was subsequently separated into three separate subgroups. Subgroups (DDS+Phc, IDS+Phc): cemented with preheated composite (Enamel plus HRi, Micerium, Italy), Subgroups (DDS+Dcrs, IDS+Dcrs): cemented with dual-cured resin cement (RelyX Ultimate, 3M ESPE, Germany) and Subgroups (DDS+Fc, IDS+Fc): Cemented with flowable composite (Filtek supreme flowable, 3M ESPE, USA). Using a digital microscope with a magnification of 230x, the marginal gap was measured before and after cementation at four different locations from each surface of the tooth, and the mean of measurements was calculated and analyzed statistically using the independent t-test, one-way ANOVA test, Bonferroni correction at a significance level of 0.05. Results: The samples that were immediately sealed with dentin bonding agent showed lower marginal gaps than delayed dentin sealing, both pre-and post-cementation for all subgroups, with a statistically significant difference (p˂0.01). The marginal gap was significantly lower in the IDS+Fc (48.888 ±5.5 µm) followed by the IDS+Dcrs group (53.612 ±5.8 µm) and IDS+Phc (79.19 9±6.9 µm) respectively, while the largest marginal gaps were observed in the DDS+Phc group (86.505 ±5.4 µm). Conclusion: Generally, the teeth with IDS showed better marginal adaptation than teeth without IDS. The marginal gap was smaller with flowable composite and dual-cure resin cement than with preheated composite (AU)

Objetivo:Esse estudo avaliou o efeito do selamento imediato da dentina na adaptação marginal de overlays em dissilicato de lítio com três tipos diferentes de agentes de cimentação resinosos: resina composta pré-aquecida, adesivo resinoso dual e resina fluida. Materiais e métodos: Quarenta e oito primeiros pré-molares maxilares com tamanho similar foram preparados com término em ombro. O dente foi separado em dois grupos primários, cada um com vinte e quatro dentes: Grupo DDS: retardado selamento da dentina (non-IDS) dente não foi tratado. Grupo IDS: selamento dentinário foi aplicado imediatamente após a preparação do dente. Cada grupo foi separado de modo subsequente em três subgrupos. Subgrupo (DDS+Phc, IDS+Phc): cimentado com resina pré-aquecida (Enamel plus HRi, Micerium, Italy), Subgrupo (DDS+Dcrs, IDS+Dcrs): cimentado com cimento resinoso dual (RelyX Ultimate, 3M ESPE, Germany) e Subgrupo (DDS+Fc, IDS+Fc): cimentado com resina fluida (Filtek supreme flowable, 3M ESPE, USA). Usando um microscópio digital com magnificação de 230x, o gap marginal foi medido antes e após a cimentação em quatro diferentes localizações de cada superfície do dente e a média das medidas foi calculada e estatisticamente analisada através do uso do teste ANOVA um-fator e teste independente de Tukey e correção Bonferroni com nível de significância de 0,05. Resultado: As amostras que foram imediatamente seladas com agente adesivo dentinário apresentaram menores gaps marginais do que o selamento dentinário retardado, ambos pré e pós cimentação para todos os subgrupos apresentaram diferença estatística significante (p˂0.01). O gap marginal foi significativamente menor para IDS+Fc (48.888 ±5.5 µm) acompanhado do IDS+Dcrs group (53.612 ±5.8 µm) e IDS+Phc (79.19 9 ±6.9 µm) respectividamente, enquanto o maior gap marginal foi observado no grupo DDS+Phc (86.505 ±5.4 µm). Conclusão:Geralmente, o dente com IDS apresentou melhor adaptação marginal do que o dente sem IDS. O gap marginal foi menor com resina fluida e cimento resinoso dual do que com a resina composta pré-aquecida (AU)

Effect of adhesive primer application on shear bond strength of self-adhesive cement to tooth structure and two different CAD/CAM milled blocks / Efeito da aplicação do primer adesivo na resistência ao cisalhamento do cimento autoadesivo à estrutura dentária e a dois diferentes blocos fresados CAD/CAM

Objective: This study was conducted to evaluate the influence of the G-CEM ONE adhesive enhancing primer on the shear bond strength of self-adhesive resin cement (G-CEM ONE) to both tooth structure and two different CAD/CAM blocks (GC Initial LiSi and Cerasmart 270). Material and Methods: Forty specimens (cylindrical-shaped, 5 mm in diameter and height) were milled from both CAD/CAM blocks (20 specimens from each block type). Forty sound upper premolars were sectioned to the level of peripheral dentin, then randomly divided into four groups (n = 10): A1: GC Initial LiSi without adhesive enhancing primer; B1: Cerasmart 270 without adhesive enhancing primer; A2: GC Initial LiSi with adhesive enhancing primer; B2: Cerasmart 270 group with adhesive enhancing primer application. The CAD/CAM blocks were cemented on teeth using a self-adhesive resin cement (G-cem one). The shear bond strength was assessed using a computerized universal testing machine. A digital microscope was used to study the mode of failure. The shear bond strength values data were analyzed statistically using paired t-test and independent t-test at the significance level of (0.05). Results: A significant difference was shown in the shear bond strength values among groups (P =0.000). The highest shear bond strength value was revealed in group A2, while group B1 exhibited the lowest shear bond strength value. Conclusion: Using the adhesive enhancing primer on the tooth's surface improved the resin cement's bond strength to CAD/CAM blocks. Additionally, GC Initial LiSi exhibited higher bond strength than Cerasmart 270, with or without the primer (AU)

Objetivo: Este estudo foi conduzido para avaliar a influência do primer adesivo G-CEM ONE na resistência ao cisalhamento do cimento resinoso autoadesivo (G-CEM ONE) tanto na estrutura dentária quanto em dois diferentes blocos CAD/CAM (GC Initial LiSi e Cerasmart 270). Material e Métodos: Quarenta corpos de prova (formato cilíndrico, 5 mm de diâmetro e altura) foram fresados em blocos CAD/CAM (20 corpos de prova de cada tipo de bloco). Quarenta pré-molares superiores sadios foram seccionados até o nível da dentina mais externa e, em seguida, divididos aleatoriamente em quatro grupos (n = 10): A1: GC Initial LiSi sem primer adesivo; B1: Cerasmart 270 sem primer adesivo; A2: GC Initial LiSi com primer adesivo; B2: Grupo Cerasmart 270 com aplicação de primer adesivo. Os blocos CAD/CAM foram cimentados nos dentes com cimento resinoso autoadesivo (G-CEM ONE). A resistência ao cisalhamento foi avaliada utilizando uma máquina de ensaios universal computadorizada. Um microscópio digital foi utilizado para estudar o modo de falha. Os dados dos valores de resistência ao cisalhamento foram analisados estatisticamente por meio do teste t pareado e teste t independente ao nível de significância de (0,05). Resultados: Foi demonstrada diferença significativa nos valores de resistência ao cisalhamento entre os grupos (P =0,000). O maior valor de resistência ao cisalhamento foi revelado no grupo A2, enquanto o grupo B1 exibiu o menor valor de resistência ao cisalhamento. Conclusão:A utilização do primer adesivo na superfície dentária melhorou a resistência de união do cimento resinoso aos blocos CAD/CAM. Além disso, o GC Initial LiSi apresentou maior resistência de união que o Cerasmart 270, com ou sem primer.(AU)

Fatigue resistance of monolithic and multilayer zirconia crowns using veneer layering or CAD-on technique

Abstract This study aims to evaluate the fatigue resistance of monolithic zirconia (Yz) and multilayer ceramic structures using the CAD-on technique in different thicknesses. Fifty (N=50) standardized single crowns preparations were made in fiberglass-reinforced epoxy resin (NEMA grade G10), digitalized, and restorations were machined in CAD-CAM, composing 5 groups (n= 10): Control: 1.5 mm (milled zirconia framework + manual layered porcelain); Yz monolithic 1.5 mm; Yz monolithic 1.0 mm; CAD-on 1.5 mm; and CAD-on 1.0 mm (milled zirconia framework 0.5 mm thickness bonded by a low fuse ceramic to a milled lithium disilicate layer of 1.0 mm or 0.5 mm, respectively). The G10 bases were conditioned with 10% hydrofluoric acid; the crowns were air abraded with 110 μm alumina particles; and then luted onto each other with self-adhesive resin cement. A cyclic fatigue test was performed (initial load: 400N for 10,000 cycles, frequency of 20 Hz, step size of 200N) until failure, and the data was submitted to a survival statistical analysis. No failures were observed at Yz monolithic 1.5 mm. High and similar performance was observed for Cad-On groups and Yz monolithic 1.0 mm. The control group depicted the worst behavior. The Weibull modulus of CAD-on 1.5 mm was higher than the control while being similar to the other conditions. Both the monolithic systems and the CAD-on technique showed high and similar fatigue fracture behavior and survival rates, which were also higher than the control bilayer system. Both systems reduced the occurrence of delamination failures, making them suitable for clinical use.

Resumo Este estudo teve como objetivo avaliar o comportamento à fadiga de estruturas cerâmicas monolíticas de zircônia (Yz) e multicamadas utilizando a técnica CAD-on em diferentes espessuras. Cinquenta (N=50) preparos unitários padronizados foram confeccionados em resina epóxi reforçada com fibra de vidro (NEMA grau G10), digitalizados e as restaurações usinadas em CAD-CAM, compondo 5 grupos (n= 10): Controle: 1,5 mm (estrutura de zircônia fresada + porcelana estratificada manualmente); Yz monolítica 1,5 mm; Yz monolítica 1,0 mm; CAD-on em 1,5 mm; e CAD-on 1,0 mm (estrutura de zircônia fresada com 0,5 mm de espessura ligada por uma cerâmica de baixa fusão a uma camada de dissilicato de lítio fresado de 1,0 mm ou 0,5 mm, respectivamente). As bases do G10 foram condicionadas com ácido fluorídrico a 10%; as coroas foram jateadas com partículas de alumina de 110 μm; e então cimentadas uma sobre a outra com cimento resinoso autoadesivo. Foi realizado um teste de fadiga cíclica (carga inicial: 400N para 10.000 ciclos, frequência de 20 Hz, step de 200N) até a falha, e os dados foram submetidos a uma análise estatística de sobrevivência. Nenhuma falha foi observada para Yz monolítica de 1,5 mm. Desempenho alto e semelhante foi observado para os grupos Cad-On e Yz monolítica 1,0 mm. O grupo controle apresentou o pior comportamento. O módulo de Weibull do CAD-on 1,5 mm foi maior que o grupo controle, sendo semelhante às outras condições. Tanto os sistemas monolíticos quanto a técnica CAD-on apresentaram alto e semelhante desempenho mecânico e taxas de sobrevivência, que também foram superiores ao sistema bicamada de controle. Ambos os sistemas reduziram a ocorrência de falhas de delaminação, tornando-os adequados para uso clínico.

Biomechanical behavior of different designs of hybrid abutment-restoration on the posterior crown: a finite element analysis

Abstract This study aimed to evaluate the influence of material and crown design on the biomechanical behavior of implant-supported crowns with hybrid abutment (HA) through three-dimensional (3D) finite element analysis. The study factors were the type of material used as the mesostructure or crown (zirconia, lithium disilicate, and hybrid ceramic) and the crown design cemented to the titanium base (mesostructure cemented to the titanium base and a crown cemented on it (HaC); hybrid crown-abutment, the abutment and crown are manufactured as a single piece and cemented to the titanium base (HC); monolithic crown cemented on the titanium base and screwed to the implant (CS); and monolithic crown cemented on the titanium base (CC). Four 3D models were constructed using an implant with an internal connection, and an oblique load of 130 N was applied at 45° to the long axis of the implant. The models were evaluated using the von Mises stress for crown, abutment, screw, and implant and maximum principal stress for bone tissues. The lowest stresses occurred in the groups with a lower elastic modulus material, mainly hybrid ceramics, considered a material with greater resilience. The cemented crown group presented the lowest stress values. The stresses were concentrated in the cervical region of the crown at the titanium crown/base interface. Mesostructures made of materials with a higher elastic modulus exhibited a higher concentration of stress. The presence of a screw hole increased the stress concentration in the ceramic crown. Cemented ceramic crowns exhibited better biomechanical behavior than screw-retained crowns.

Resumo O estudo teve como objetivo avaliar a influência do material e do desenho da coroa no comportamento biomecânico de coroas implanto-suportadas com pilar híbrido (AH) por meio da análise tridimensional (3D) de elementos finitos. Os fatores de estudo foram o tipo de material do HA ou coroa (zircônia, dissilicato de lítio e cerâmica híbrida) e o desenho da coroa sobre a base de titânio (mesoestrutura cimentada à base de titânio e coroa total cimentada em cerâmica; pilar e coroa fabricados em peça única cimentada à base de titânio; coroa monolítica cimentada sobre a base de titânio e aparafusada ao implante; e coroa monolítica cimentada à base de titânio). Quatro modelos 3D foram construídos e uma carga oblíqua de 130 N foi aplicada a 45° em relação ao longo eixo do dente. Os modelos foram avaliados utilizando a tensão de von Mises para a coroa, pilar, parafuso, implante e tensão principal máxima (tensão de tração) para o tecido ósseo. As menores tensões ocorreram nos grupos que apresentaram um material com menor módulo de elasticidade, principalmente a cerâmica híbrida, considerada um material com maior resiliência. Com relação às diferentes configurações, o modelo com coroa cimentada apresentou os menores valores de tensão. As tensões foram concentradas na região cervical da coroa na interface entre coroa e base de titânio. Mesoestruturas feitas de materiais com maior módulo de elasticidade exibiram maior concentração de tensões. A presença de um orifício para parafuso aumentou a concentração de tensão na coroa de cerâmica. As coroas cerâmicas cimentadas exibiram melhor comportamento biomecânico do que as coroas parafusadas.

Sistema CAD/CAM en la confección de prótesis totales dentales / The CAD/CAM system in the fabrication of total dental prostheses

La técnica CAD/CAM es un sistema que ha facilitado los procesos de toma de impresiones totales e incorpora registros intraorales y requisitos apropiados para lograr bases protésicas adecuadas, lo cual permite óptimos resultados en clínica dental, como son el ahorro de tiempo y la comodidad para el especialista y el paciente, razones que llevan al profesional estomatológico a dar el paso hacia una odontología digital. El objetivo del estudio fue analizar el sistema CAD/CAM en la confección de prótesis totales dentales. La búsqueda se realizó en las bases de datos Google Scholar, Pubmed y Scopus, intentando responder a la pregunta orientadora: ¿Cuáles son los aspectos más significativos para el sistema CAD/CAM en la confección de prótesis totales dentales? Como resultados, se pudo interpretar que, consiguiendo registros tridimensionales producidos en un escáner, se proporciona una mejor adaptación de estructuras respecto a los métodos convencionales, por lo que induce estética y precisión, que son factores importantes en la odontología. Se concluyó que el sistema CAD/CAM disminuye el margen de error humano y conduce a mayores éxitos odontológicos, al brindar un mejor soporte para la toma decisiones y conseguir mejores resultados estéticos y funcionales en las prótesis totales de los pacientes(AU)

The CAD/CAM technique is a system that has facilitated the process of taking total impressions and incorporates intraoral records and appropriate requirements to achieve adequate prosthetic bases, which allows optimal results in the dental clinic, such as time savings and comfort for the specialist and the patient, reasons that lead the dental professional to take the step towards digital dentistry. The objective of the study was to analyze the CAD/CAM system in the fabrication of total dental prostheses. The search was carried out in Google Scholar, Pubmed and Scopus databases, trying to answer the guiding question: What are the most significant aspects for the CAD/CAM system in the manufacture of total dental prostheses? As results, it was possible to interpret that, by obtaining three-dimensional records produced in a scanner, it provides a better adaptation of structures compared to conventional methods, thus inducing esthetics and precision, which are important factors in dentistry. It was concluded that the CAD/CAM system reduces the margin of human error and leads to greater dental success by providing better support for decision making and achieving better esthetic and functional results in the total prostheses of patients(AU)

Effect of laboratory and chairside polishing methods on the surface topography of occlusal splint materials manufactured using conventional, subtractive and additive digital technologies / Efeito de métodos de polimento em laboratório e em consultório na topografia de superfície de materiais de splint oclusal fabricados usando tecnologias digitais convencionais, subtrativas e aditivas

Objetivo: Este estudo avaliou as propriedades de polimento dos materiais de splint oclusal obtidos usando métodos de fabricação subtrativos e aditivos com os procedimentos de polimento laboratorial (LP) e polimento em consultório (CP). Material e Métodos: As amostras (N=180, n=60 para cada grupo) foram fabricadas usando um dos seguintes métodos: método de fabricação subtrativo (SMM) (M-PM Disc, Merz Dental GmbH), método de fabricação aditivo (AMM) (Freeprint Splint 2.0, DETAX GmbH & Co. KG) e o método de fabricação convencional (CMM) (Promolux HC, Merz Dental GmbH). Seguindo os procedimentos de LP e CP, a rugosidade da superfície dos espécimes foi medida usando um perfilômetro de superfície digital. Um espécime representativo foi selecionado de cada grupo, e uma imagem de microscópio eletrônico de varredura (SEM) foi obtida. Resultados: Tanto o método de fabricação quanto os procedimentos de polimento afetaram significativamente os resultados (P<0,01). Os termos de interação também foram significativos (P<0,001). Conclusão: Com ambos os métodos de polimento, a rugosidade superficial do grupo AMM foi a maior e a do grupo CMM a menor. Embora o procedimento CP tenha sido mais eficaz do que LP com ambos os métodos, a rugosidade da superfície ficou abaixo do limite de 0,2 µm após ambos os procedimentos de polimento testados (AU)

Objective: This study evaluated the polishing properties of the occlusal splint materials obtained using subtractive and additive manufacturing methods with the laboratory-type polishing (LP) and chairside-type polishing (CP) procedures. Material and Methods: Specimens (N=180, n=60 each group) were manufactured using one of the following methods: subtractive manufacturing method (SMM) (M-PM Disc, Merz Dental GmbH), additive manufacturing method (AMM) (Freeprint Splint 2.0, DETAX GmbH & Co. KG), and the conventional manufacturing method (CMM) (Promolux HC, Merz Dental GmbH). Following LP and CP procedures, surface roughness of the specimens was measured using a digital surface profilometer. One representative specimen was selected from each group, and a scanning electron microscope (SEM) image was made. Results: Both the manufacturing method and the polishing procedures significantly affected the results (P<0.01). Interaction terms were also significant (P<0.001). Conclusion: With both polishing methods, surface roughness of the AMM group was the highest and the CMM group the least. Although the CP procedure was more effective than LP with both methods, surface roughness was below the 0.2 µm threshold after both polishing procedures tested. (AU)

La technologie CAD CAM: enquête auprès des techniciens dentaires de la ville de Rabat / CAD/CAM-Technology: A Survey among dental technicians in Rabat

La profession de prothésiste dentaire évolue et s'inscrit pleinement dans l'ère numérique. Cette révolution technologique s'est fait connaître sous le nom de CFAO dentaire (conception et fabrication Assistées par ordinateur), qui regroupe l'ensemble des étapes de numérisation et de conception informatique (CAO) et celles de fabrication à l'aide des machines-outils (FAO). La CFAO dentaire date de plus de 40 ans avec la thèse du Dr François Duret en 1973 intitulée « l'empreinte optique ¼, son développement a été, et reste encore, intimement dépendant des évolutions et des progrès de l'ingénierie et de l'informatique. Au sein du laboratoire de prothèse dentaire, la CFAO a connu une ascension fulgurante. En effet, cette technique a totalement modifié la pratique quotidienne des prothésistes dentaires en remplaçant certaines techniques traditionnelles. Cette nouvelle façon de concevoir les prothèses a permis ainsi aux laboratoires d'améliorer leurs travaux en termes de précision, de reproductibilité et de diversité des matériaux, tout cela en diminuant les erreurs en liaison avec le facteur humain. La CFAO a-elle véritablement remplacé les techniques conventionnelles dans la réalisation des prothèses dentaires ? Présente-t-elle de véritables avantages pour les prothésistes ? La CFAO a-t-elle un avenir au sein des futurs laboratoires de prothèse dentaire ? C'est dans ce sens que ce travail a été mené, afin d'étudier l'intégration et l'utilisation de la CFAO au laboratoire dentaire, à travers une enquête descriptive auprès des prothésistes dentaires exerçant dans la ville de Rabat, et de comprendre l'impact de cette technique sur l'exercice quotidien du prothésiste.

The dental technician profession is evolving and is fully integrated into the digital era. This technological revolution has become known under the name of dental CAD/CAM (computer-aided design and computer-aided manufacturing), which includes all the steps of digitization and computer design (CAD) and those of manufacturing with the help of machine tools (CAM). Dental CAD/CAM dates back more than 40 years with the thesis of Dr. François Duret in 1973 entitled "the optical impression", its development has been, and still is, intimately dependent on the evolution and progress of engineering and computer science. In the dental laboratory, CAD/CAM is on a meteoric rise. Indeed, this technique has completely changed the daily practice of dental technicians by replacing certain traditional techniques. This new way of designing prostheses has enabled laboratories to improve their work in terms of precision, reproducibility, and diversity of materials while reducing errors related to the human factor. Has CAD/CAM replaced conventional techniques in producing dental prostheses? Does it offer real advantages for dental technicians? Does CAD/CAM have a future in the dental laboratories of the future? In this sense, this work was conducted to study the integration and use of CAD/CAM in the dental laboratory through a descriptive survey of dental technicians practicing in the city of Rabat and to understand the impact of this technique on the daily practice of the prosthetist.

Influence of cavity design on quality of margin and marginal adaptation and microleakage of all-ceramic CAD/CAM inlays / 北京大学学报(医学版)

OBJECTIVE@#To investigate the influence of 135° and 90° cavity design on quality of margin and marginal adaptation and microleakage of all-ceramic computer aided design/computer aided manufacturing (CAD/CAM) inlays.@*METHODS@#One hundred extracted human molars were prepared by criteria of buccal occlusal (BO) inlay. On the buccal, the mesial margin was prepared as 135° bevel while the distal margin was prepared as butt-joint. All-ceramic restorations were made in the Sirona CEREC AC CAD/CAM system with VitaBlocs Mark Ⅱ, Upcera UP.CAD, IPS e.max CAD, Upcera Hyramic and Lava Ultimate. The gaps between each inlay's mesial margin-abutment and distal margin-abutment were recorded under an optical microscope. Each inlay was adhered to the abutment and aged by thermal cycling for 10 000 times. Each specimen was cut into 3 slices after staining. Dye penetration was evaluated under an optical microscope for mesial and distal margins.@*RESULTS@#Mean marginal integrity rate, mean marginal gap value and mean depth of microleakage of 135° margin of Group Upcera Hyramic and Lava Ultimate were significantly better than those of Group VitaBlocs Mark Ⅱ, Upcera UP.CAD and IPS e.max CAD(P < 0.05). Mean marginal gap value, mean depth of microleakage and scale of mean depth of microleakage of 90° margin of Group Upcera Hyramic and Lava Ultimate were significantly better than those of Group Upcera UP.CAD and IPS e.max CAD (P < 0.05) while mean marginal integrity rate was not significantly different (P>0.05). Mean marginal integrity rate of 90° margin was significantly better than that of 135° margin in each group (P < 0.05) while mean depth of microleakage between different margins was not significantly different in each group (P>0.05). Mean marginal gap value of 90° margin of Group VitaBlocs Mark Ⅱ and IPS e.max CAD was significantly better than that of 135° margin (P < 0.05) while there was not significant difference in other 3 groups between 90° and 135° margin (P>0.05). Scale of mean depth of microleakage of 135° margin of Group Upcera Hyramic and Lava Ultimate was significant better than that of 90° margin (P < 0.05) while there was not significantly different in other 3 groups between 90° and 135° margin (P>0.05).@*CONCLUSION@#The mesial and distal margins of abutement of all-ceramic inlay should be prepared as butt-joint.

Correction of hemifacial microsomia using preformed titanium mesh combined with contralateral mandibular angle bone graft with CAD/CAM assistance / 口腔医学

@#Objective To explore the indications and clinical effects of simultaneous mandibular angleplasty on the unaffected side, performed using preformed titanium mesh combined with mandibular angle bone graft, for the treatment of hemifacial microsomia (HFM). Methods The study group included 11 patients between 2013 and 2021 with HFM who underwent simultaneous mandibular angle reduction of the unaffected side and augmentation of the affected side using resected bone scaffolds within the titanium mesh. A series of mandibular linear measurements such as ramus height(RH)and mandibular body length(BL), angular measurements, and asymmetry index combined with clinical photographs and postoperative complications were used to assess the therapeutic effect. Results Postoperatively, all patients were satisfied. Significant improvement in mandibular contour was shown, with no obvious complications. Postoperative data, such as BL and angular measurements, showed no statistically significant differences(P>0.05) between the affected and unaffected sides with improvement in symmetry, except for RH(P<0.05). The preoperative and postoperative asymmetry index were (17.11±4.56)% and (4.81±1.73)%, respectively, with significant improvement(P=0.002). Conclusion This approach provides satisfactory results and significantly improves facial asymmetries for unilateral HFM with hypertrophy of the contralateral mandibular angle.

Odontologia digital - abordagem histórica e conceitual: uma revisão de literatura / Digital dentistry - historical and conceptual approach: a literature review

Introdução: as inovações tecnológicas contribuem e representam um papel importante em diversos aspectos da vida cotidiana dos indivíduos em sociedade. Diferentes áreas do conhecimento trabalham com as ferramentas tecnológicas e digitais, dentre estas áreas, destaca-se a Odontologia e suas especialidades. A Odontologia digital e suas tecnologias associadas têm se destacado de forma progressiva, abordando desde os planejamentos restauradores de forma virtual, as impressões de modelos em impressora 3D e os métodos de confecção de próteses em fresadoras auxiliadas por computadores. Objetivo: este trabalho tem como objetivo realizar uma revisão de literatura, com uma abordagem conceitual e histórica acerca da Odontologia digital, do escaneamento intraoral e da confecção laboratorial das restaurações indiretas por meio dos sistemas CAD/CAM. Fonte dos dados: a pesquisa na literatura foi feita utilizando-se as bases de dados Medline® (PubMed), Scielo e Bireme com as seguintes palavras chaves: "CAD/CAM", "dental prothesis", "dental porcelain", "digital dentistry", "dental scanner", "digital impression". Síntese dos dados: os estudos demonstraram grandes avanços nas técnicas de moldagem com o escaneamento intraoral permitindo a obtenção de imagens fidedignas dos dentes e estruturas adjacentes de forma precisa, otimizando o tempo clínico. Além disto, o desenvolvimento de novos métodos e materiais dentários tem possibilitado a elaboração de modelos de trabalho, restaurações indiretas e infraestruturas de próteses por meio de um processo totalmente digital. Conclusão: podemos concluir que os estudos reportam resultados promissores com os métodos de trabalho por meio do fluxo digital. Além disso, é notável que esta realidade na Odontologia restauradora e reabilitadora continuará evoluindo e possibilitando o acesso a um maior número de profissionais.

Introduction: technological innovations are important and present an important role in various aspects in lives of individuals in society. Different areas of knowledge working with technological and digital tools, and among these areas, Dentistry and its specialties stand out. In the last decades, digital Dentistry and its associated technologies have been highlighting in a progressive way, approaching from the virtual restorative planning, 3D printed models to the prosthesis manufacturing methods in milling machines aided by computer. Objective: the aim of this study is to reach out a literature review, with a conceptual and historical approach about digital Dentistry, intraoral scanning and laboratory press of indirect restorations with CAD/CAM systems. Sources of data: the literature search was done using Medline® (PubMed), Scielo and Bireme databases with the following keywords: "CAD/CAM", "dental prothesis", "dental porcelain", "3D printing". Synthesis of data: the present work demonstrates a great advance in impression technique with intraoral scan allowing the obtention of trustworthy images from teeth and surrounding structures in a precision way, optimizing clinical time. Furthermore, the development of new methods and dental materials have been allowing the elaboration of dental work cast, indirect restorations and prosthesis infrastructures in a fully digital process. Conclusion: it is possible to conclude that the articles report promising results with working methods through the digital flow. Besides that, it is remarkable that this reality in restorative and rehabilitation dentistry will be in a continuous evolution and allowing access to a greater number of professionals.

Tecnologia digital em próteses totais: propriedades dos materiais CAD-CAM e desenvolvimento de uma patente de inovação para simplificação do fluxo de trabalho / Digital technology in complete dentures: properties of CAD-CAM materials and development of an innovation patent to simplify the workflow

Recursos digitais, como a manufatura subtrativa (fresagem CAD-CAM) e a manufatura aditiva (impressão 3D) podem promover significativos avanços, reduzindo o tempo e o custo de produção de próteses totais (PTs). Assim, este estudo objetiva investigar as características superficiais (rugosidade e ângulo de contato), propriedades mecânicas (resistência mini-flexural) e a adesão de biofilme sobre polímeros de PMMA pré-polimerizado para fresagem CAD-CAM e sobre resinas para impressão 3D utilizados na fabricação de bases de PTs, bem como propor um fluxo de trabalho inovador para abreviar e simplificar as etapas de confecção de PTs. Para a análise in vitro, foram fabricados um total de 60 discos e 40 barras distribuídas igualmente em quatro grupos: fresagem CAD-CAM (GF), impressão 3D (GI) e PMMA convencional termopolimerizado por ciclo longo (GCL) ou por energia de micro-ondas (GCM). A rugosidade foi determinada pelo valor de Ra; o ângulo de contato foi medido pelo método da gota séssil; o teste de resistência à mini-flexão foi obtido por teste de flexão de três pontos, enquanto o comportamento frente à formação de biofilme foi analisado através da adesão de biofilme de C. albicans. Os dados foram analisados por meio de estatística descritiva e analítica (α = 0,05). Os resultados mostraram que o GI apresentou a maior rugosidade superficial (Ra: 0,317 ± 0,151µm) e os menores valores de resistência à miniflexão (57,23 ± 9,07MPa) e o GF apresentou a menor adesão de biofilme de C. albicans (log UFC/mL: 3,74 ± 0,57) e maior média de resistência à mini-flexão (114,96 ± 16,23 MPa). Não houve diferença estatística entre o GF e os grupos convencionais para rugosidade, ângulo de contato e resistência à mini-flexão. A patente de inovação desenvolvida estabeleceu um novo fluxo de trabalho para confecção de próteses totais através de um protocolo de três consultas em que foram feitas as moldagens anatômicas na 1ª sessão, juntamente com o registro do suporte labial, plano oclusal e linhas de referência para subsidiar a montagem dos dentes superiores. Uma prótese-teste foi confeccionada por meio de procedimentos convencionais ou CAD-CAM e avaliada na 2ª consulta, permitindo observar o resultado estético, executar a moldagem funcional e realizar o registro da relação maxilo-mandibular, fornecendo referências precisas para a confecção da prótese inferior. Com base nos resultados da fase in vitro deste estudo, os corpos-de-prova obtidos a partir de disco para fresagem CAD-CAM apresentaram resistência flexural e propriedades superficiais semelhantes às resinas convencionais e mostraram um comportamento inibidor da adesão de C. albicans, enquanto os espécimes produzidos por impressão 3D exibiram a menor resistência à flexão e a maior rugosidade da superfície. O dispositivo inovador apresentado para a execução das etapas clínicas relacionadas à fabricação de PTs mostrou-se efetivo para abreviar e simplificar as técnicas disponíveis, apresentando confiabilidade e previsibilidade para produção de PTs em número de sessões reduzido (AU).

Digital features like subtractive and additive manufacturing can promote breakthroughs by reducing the time and cost of making complete dentures (CDs). Thus, this study aims to investigate surface characteristics (roughness and contact angle), mechanical properties (mini-flexural strength), and biofilm adhesion on computer-aided design/computer-aided manufacturing (CAD-CAM) PMMA polymer, and threedimensional (3D) printed resin for denture´s base fabrication as well as to propose an innovative workflow. For in vitro analysis, a total of 60 discs and 40 rectangular specimens were fabricated from one CAD-CAM pre-polymerized PMMA disc (GF), one 3D-printed (GI), and two conventional heat-polymerized (GCL and GCM) materials for denture base fabrication. Roughness was determined by the Ra value; the contact angle was measured by the sessile drop method; the mini-flexural strength test was a three-point bending test while the biofilm formation inhibition behavior was analyzed through C. albicans adhesion. The data were analyzed using descriptive and analytical statistics (α = 0.05). Results showed that GI specimens presented the highest surface roughness (Ra: 0.317 ± 0.151 µm) and lowest mini-flexural strength values (57.23 ± 9.07 MPa) and the GF showed the lowest C. albicans adhesion (log CFU/mL: 3.74 ± 0.57) and highest mini-flexural strength mean (114.96 ± 16.23 MPa). There was no statistical difference between GF and conventional groups for roughness, contact angle, and mini-flexural strength. In turn, the presented novel workflow for complete dentures fabrication reached a three appointments protocol in which preliminary impressions were made in the 1st session, all together to maxillary registration of lip support, occlusal plane, and reference lines for teeth arrangement. A trial denture was manufactured and evaluated by the 2nd appointment through conventional or CAD-CAM procedures, allowing esthetics evaluation, final impression, and maxillomandibular relationship record and providing precise references for final dentures fabrication. Based on the findings of this in vitro study, GF presented surface and mechanical properties similar to conventional resins and show improved behavior preventing C. albicans adhesion, while GI specimens exhibited the lowest flexural strength, and highest surface roughness. The proposed device for CD´s fabrication clinical procedures reached feasibility and by simplifying available techniques, this protocol could achieve reliability and predictability to produce complete dentures with reduced working time (AU).