The natural CAD/CAM anterior implant single tooth restoration: A novel digital workflow.

OBJECTIVE: To report a novel digital workflow to replace an anterior maxillary tooth lost due to trauma with an implant multilayer restoration by using the patient's extracted tooth as a final crown restoration using computer-aided design/computer-aided manufacturing (CAD/CAM) technology. CLINICAL CONSIDERATIONS: Instead of using the patient's natural tooth as an immediate provisional restoration to achieve predictable results in terms of esthetics and soft tissue structure, a novel digital strategy was performed to obtain a natural final crown restoration by using the patient's tooth associated with a lithium disilicate customized implant abutment. CONCLUSIONS: The perspective of using this strategic approach for implant restorative dental treatments in patients with traumatic root fractures in the anterior region has great potential as it helps to maintain the emergence profile of the natural dentition and esthetics. CLINICAL SIGNIFICANCE: Optimal esthetic outcomes are challenging in implant dentistry regarding soft tissue structure and morphology factors. Using natural teeth from surgery to deliver the final restoration might be beneficial when an anterior tooth is lost due to trauma.

Quo vadis, esthetic dentistry? Ceramic veneers and overtreatment-A cautionary tale.

The increased emphasis on orofacial esthetics, experienced both by dental professionals and the lay public, results in an environment where overtreatment can easily occur. Patients on the one hand feel pressure from esthetic norms that are often unrealistic, while dental professionals are compelled to deliver immediate results many times without considering what is best for the ill-informed patient. This article is an illustrated cautionary tale against overtreatment disguised as esthetic dentistry. Representative clinical examples illustrate how porcelain veneers are used without following sound operatory principles, as well as how these cases have been resolved.

Effect of lithium disilicate ceramic thickness, shade and translucency on transmitted irradiance and knoop microhardness of a light cured luting resin cement.

This in vitro study evaluates the influence of pressed lithium disilicate thickness, shade and translucency on the transmitted irradiance and the Knoop microhardness (KHN) of a light-cured resin cement at two depths. One hundred and thirty-five ceramic discs of IPS e.max Press (Ivoclar Vivadent) were fabricated and divided into twenty-seven groups (n = 5) according to the association between translucency: HT (hight translucency), LT (low translucency), and MO (medium opacity); shade: BL2, A1 and A3.5; and thickness: 0.5 mm, 1.5 mm, and 2.0 mm. One side of each ceramic disc was finished, polished and glazed. The irradiance (mW/cm²) of a multiwave LED light curing unit (Valo, Ultradent) was evaluated with a potentiometer (Ophir 10ª-V2-SH, Ophir Optronics) without (control group) or with interposition of ceramic samples. The microhardness of Variolink Esthetic LC resin cement (Ivoclar Vivadent) was evaluated after 24 h at two depths (100 µm and 700 µm). Data were submitted to ANOVA followed by Tukey's test (α = 0.05). Irradiance and KHN were significantly influenced by ceramic thickness (p < 0.0001), shade (p < 0.001), translucency (p < 0.0001) and depth (p < 0.0001). Conclusions: the interposition of increasing ceramic thicknesses significantly reduced the irradiance and microhardness of resin cement. Increased depth in the resin cement showed significantly reduced microhardness for all studied groups. Increased ceramic opacity reduced the KHN of the resin cement at both depths for all ceramic thicknesses and shades.

Bond Strength of Resin Cements to Zirconia Ceramic Using Adhesive Primers.

PURPOSE: To evaluate the influence of adhesive primers on the microshear bond strength of resin cements to zirconia ceramic. MATERIALS AND METHODS: Fifty zirconia plates (12 mm × 5 mm × 1.5 mm thick) of a commercially available zirconium oxide ceramic (ZirCad) were sintered, sandblasted with aluminum oxide particles, and cleaned ultrasonically before bonding. The plates were randomly divided into five groups of 10. Three resin cements were selected (RelyX ARC, Multilink Automix, Clearfil SA Cement self-adhesive resin cement), along with two primers (Metal-Zirconia Primer, Alloy Primer) and one control group. The primers and resin cements were used according to manufacturers' recommendations. The control group comprised the conventional resin cement (RelyX ARC) without adhesive primer. Test cylinders (0.75 mm diameter × 1 mm high) were formed on zirconia surfaces by filling cylindrical Tygon tube molds with resin cement. The specimens were stored in distilled water for 24 hours at 37°C, then tested for shear strength on a Shimadzu EZ Test testing machine at 0.5 mm/min. Bond strength data were analyzed statistically by two-way ANOVA and Dunnett's test (5%). RESULTS: The bond strength means in MPa (± s.d.) were: RelyX ARC: 28.1 (6.6); Multilink Automix: 37.6 (4.5); Multilink Automix + Metal-Zirconia Primer: 55.7 (4.0); Clearfil SA Cement: 46.2 (3.3); and Clearfil SA Cement + Alloy Primer: 47.0 (4.1). CONCLUSION: Metal-Zirconia Primer increased the bond strength of Multilink Automix resin cement to zirconia, but no effect was observed for Alloy Primer using Clearfil SA Cement. RelyX ARC showed the lowest bond strength to zirconia.

Surface degradation of lithium disilicate ceramic after immersion in acid and fluoride solutions.

PURPOSE: To analyze whether immersion in sodium fluoride (NaF) solutions and/or common acidic beverages (test solutions) would affect the surface roughness or topography of lithium disilicate ceramic. METHODS: 220 ceramic discs were divided into four groups, each of which was subdivided into five subgroups (n = 11). Control group discs were immersed in one of four test beverages for 4 hours daily or in artificial saliva for 21 days. Discs in the experimental groups were continuously immersed in 0.05% NaF, 0.2% NaF, or 1.23% acidulated phosphate fluoride (APF) gel for 12, 73, and 48 hours, respectively, followed by immersion in one of the four test beverages or artificial saliva. Vickers microhardness, surface roughness, scanning electron microscopy (SEM) associated with energy dispersive spectroscopy, and atomic force microscopy (AFM) assessments were made. Data were analyzed by nested analysis of variance (ANOVA) and Tukey's test (α = 0.05). RESULTS: Immersion in the test solutions diminished the microhardness and increased the surface roughness of the discs. The test beverages promoted a significant reduction in the Vickers microhardness in the 0.05% and 0.2% NaF groups. The highest surface roughness results were observed in the 0.2% NaF and 1.23% APF groups, with similar findings by SEM and AFM. Acidic beverages affected the surface topography of lithium disilicate ceramic. Fluoride treatments may render the ceramic surface more susceptible to the chelating effect of acidic solutions.

Estudo clínico retrospectivo de restaurações cerâmicas do tipo laminado sobre dentes com ou sem preparo dentário: 1 a 5 anos de acompanhamento / A 5-year retrospective and clinical follow-up of ceramic laminate veneers on prep and noprep teeth

Com a evolução da adesão sobre tecidos dentários e cerâmicas vítreas na década de 80, tratamentos com abordagem mais conservadora em prótese dentária tem sido crescentemente sugeridos, com ênfase no uso de laminados cerâmicos, incluindo, mais recentemente, a possibilidade de tratamento sem a necessidade de desgaste na estrutura dentária. Embora sua possibilidade de aplicação seja real, poucos estudos longitudinais demonstram sua efetividade clínica. Assim, o objetivo deste estudo é fazer uma análise retrospectiva de 5 anos de experiência com restaurações laminados cerâmicos aplicados sobre dentes com ou sem preparo dentário. Materiais e Métodos: Um total de 240 restaurações foi realizado em 40 pacientes no segmento anterior superior, compreendendo de canino a canino, onde, em 29 pacientes, um total de 174 restaurações laminadas cerâmicas de dissilicato de lítio (LS2) foram realizadas sobre dentes com preparo dentário e, em 11 pacientes, 66 restaurações foram realizadas sobre dentes sem preparo dentário, entre os anos de 2007 e 2013. Estas restaurações foram avaliadas sobre os critérios de estabilidade de cor e integridade da restauração, descoloração e integridade da margem através dos critérios de Ryge modificados, California Dental Association (CDA/Ryge criteria). Resultados: Nos critérios de base utilizados, uma ampla porcentagem de restaurações foi classificada como A, e apenas 2 (1,15%) restaurações realizadas sobre dentes com preparo dentário falharam por fratura com a necessidade de troca (D), 4 (2,3%) tiveram pequenas alterações de cor, 1 (0,6%) teve descoloração superficial da margem (B) e 2 (1,15%) tiveram pequenas alterações na margem cervical (B). No grupo de restaurações sobre dentes sem preparo dentário, 7 (10,6%) restaurações tiveram descoloração superficial da margem (B) e nenhuma restauração teve de ser trocada. No total das restaurações avaliadas o índice de sucesso foi de 99,2%. Foi observada maior ocorrência de alterações de coloração...

Based on scientific and clinical evidence of adhesion to dental tissues and glass-ceramics in the 80s, more conservative treatment approach for dental prosthesis has been increasingly suggested. Among the most used therapies, the technique of ceramic laminate veneers are widely used in different clinical situations. Currently, from experience of applying the laminate restorations on teeth with dental preparation, some clinical situations have allowed the application of these restorations directly to the teeth without having to wear on tooth structure. Although the possibility of their application to real, few longitudinal studies have demonstrated the clinical effectiveness. The main of this study was to evaluate in a long-term of up to 5 years. In this study were evaluated ceramic laminate restorations applied to teeth with or without preparation. Materials and Methods: A total of 240 restorations were performed in 40 patients in the upper anterior segment, comprising from canine to canine, where in 29 patients, a total of 174 restorations laminated ceramic lithium disilicate (LS2) were performed on teeth with preparation, and 11 patients, 66 restorations were performed on teeth without preparation, between 2007 and 2013 at private clinic. Color stability and integrity of restoration, discoloration and integrity of the border were evaluated following modified California Dental Association (CDA / Ryge criteria). Results: a large percentage of restorations were classified as A, and only 2 (1.15%) restorations on teeth with preparation failed by fracture with the need to change (D), 4 (2, 3%) had minor color changes, 1 (0.6%) had superficial discoloration of the margin (B) and 2 (1.15%) had minor changes in the cervical margin (B). In the group of teeth without dental restorations, 7 preparation (10.6%) had superficial discoloration of restoration margins (B) and no restoration had to be replaced. In total restorations evaluated the success rate was 99.2%...

Estudo clínico retrospectivo de restaurações cerâmicas do tipo laminado sobre dentes com ou sem preparo dentário: 1 a 5 anos de acompanhamento / A 5-year retrospective and clinical follow-up of ceramic laminate veneers on prep and noprep teeth

Com a evolução da adesão sobre tecidos dentários e cerâmicas vítreas na década de 80, tratamentos com abordagem mais conservadora em prótese dentária tem sido crescentemente sugeridos, com ênfase no uso de laminados cerâmicos, incluindo, mais recentemente, a possibilidade de tratamento sem a necessidade de desgaste na estrutura dentária. Embora sua possibilidade de aplicação seja real, poucos estudos longitudinais demonstram sua efetividade clínica. Assim, o objetivo deste estudo é fazer uma análise retrospectiva de 5 anos de experiência com restaurações laminados cerâmicos aplicados sobre dentes com ou sem preparo dentário. Materiais e Métodos: Um total de 240 restaurações foi realizado em 40 pacientes no segmento anterior superior, compreendendo de canino a canino, onde, em 29 pacientes, um total de 174 restaurações laminadas cerâmicas de dissilicato de lítio (LS2) foram realizadas sobre dentes com preparo dentário e, em 11 pacientes, 66 restaurações foram realizadas sobre dentes sem preparo dentário, entre os anos de 2007 e 2013. Estas restaurações foram avaliadas sobre os critérios de estabilidade de cor e integridade da restauração, descoloração e integridade da margem através dos critérios de Ryge modificados, California Dental Association (CDA/Ryge criteria). Resultados: Nos critérios de base utilizados, uma ampla porcentagem de restaurações foi classificada como A, e apenas 2 (1,15%) restaurações realizadas sobre dentes com preparo dentário falharam por fratura com a necessidade de troca (D), 4 (2,3%) tiveram pequenas alterações de cor, 1 (0,6%) teve descoloração superficial da margem (B) e 2 (1,15%) tiveram pequenas alterações na margem cervical (B). No grupo de restaurações sobre dentes sem preparo dentário, 7 (10,6%) restaurações tiveram descoloração superficial da margem (B) e nenhuma restauração teve de ser trocada. No total das restaurações avaliadas o índice de sucesso foi de 99,2%. Foi observada maior ocorrência de alterações de coloração...

Based on scientific and clinical evidence of adhesion to dental tissues and glass-ceramics in the 80s, more conservative treatment approach for dental prosthesis has been increasingly suggested. Among the most used therapies, the technique of ceramic laminate veneers are widely used in different clinical situations. Currently, from experience of applying the laminate restorations on teeth with dental preparation, some clinical situations have allowed the application of these restorations directly to the teeth without having to wear on tooth structure. Although the possibility of their application to real, few longitudinal studies have demonstrated the clinical effectiveness. The main of this study was to evaluate in a long-term of up to 5 years. In this study were evaluated ceramic laminate restorations applied to teeth with or without preparation. Materials and Methods: A total of 240 restorations were performed in 40 patients in the upper anterior segment, comprising from canine to canine, where in 29 patients, a total of 174 restorations laminated ceramic lithium disilicate (LS2) were performed on teeth with preparation, and 11 patients, 66 restorations were performed on teeth without preparation, between 2007 and 2013 at private clinic. Color stability and integrity of restoration, discoloration and integrity of the border were evaluated following modified California Dental Association (CDA / Ryge criteria). Results: a large percentage of restorations were classified as A, and only 2 (1.15%) restorations on teeth with preparation failed by fracture with the need to change (D), 4 (2, 3%) had minor color changes, 1 (0.6%) had superficial discoloration of the margin (B) and 2 (1.15%) had minor changes in the cervical margin (B). In the group of teeth without dental restorations, 7 preparation (10.6%) had superficial discoloration of restoration margins (B) and no restoration had to be replaced. In total restorations evaluated the success rate was 99.2%...

Cimentação adesiva de laminados cerâmicos E. max / Adhesive cementation of E. max ceramic laminates

A etapa de cimentação é de fundamental importância para o tratamento restaurador usando laminados cerâmicos. É nessa etapa que normalmente são verificados os erros e acertos nas etapas anteriores de planejamento, preparo e moldagem dos laminados. É fundamental que o dentista conheça essa etapa, desde o tratamento da superfície interna da restauração cerâmica até o preparo do substrato dental para a técnica adesiva. Dessa forma, o objetivo desse artigo é mostrar de forma segura a cimentação de laminados cerâmicos reforçados por dissilicato de lítio, o que garante um resultado final satisfatório do tratamento conservador estético

Bone stress evaluation in implants with Regular and Switching platforms / Avaliação da tensão óssea em implantes com plataforma Regular e Switching

Objective: Considering that the bone stress caused by the internal hexagon implant is lower in comparison with that caused by external hexagon implant, the aim of this study was to evaluate stress distribution of the peri-implant bone, by simulating the influence of the switching platform in external hexagon implants in comparison with regular platform in the internal hexagon implant. Methods: Two mathematical models of an implant-supported central incisor were created: Regular (R), 4.5 x 11.5 mm internal hexagon implant and 4.5 mm abutment and Switching (S), 5.0 x 11.5 mm external hexagon implant and 4.1 mm abutment. The models were created using the SolidWorks 2010 (3Dtech, São Paulo, Brazil) program. Oblique forces (100 N) were applied to the palatine surface of the central incisor. The bone/implant interface was considered perfectly integrated. Maximum and minimum principal stress values were evaluated in the cortical and medullary bones. The numerical analysis was performed using the ANSYS Workbench 10.0 (Swanson Analysis System, Houston, Pa). Results: For the cortical bone, the highest stress values were observed in the R (48.8 MPa), followed by the S (48.5 MPa). For the medullary bone, the highest stress values were observed in the S (3.66 MPa), followed by the regular (1.51 MPa). Conclusion: External hexagon implant with switching platform showed a biomechanical performance similar to that of the internal hexagon implant with regular platform in the cortical bone analysis. Whereas, for the medullary bone, the switching platform model transmitted more stress than the regular model.

Objetivo: Avaliar a distribuição de tensão no osso peri-implantar de implante hexágono interno com plataforma regular e implante hexágono externo com plataforma switching. Métodos: Foram confeccionados dois modelos matemáticos representativos de uma maxila parcial da região do elemento 11, sendo um modelo Regular, com implante hexágono interno (4,5 x 11,5 mm) e pilar 4,5 mm e outro modelo Switching, com implante hexágono externo (5,0 x 11,5 mm) e pilar 4,1 mm. Ambos os modelos continham uma coroa cimentada sobre o pilar do implante. Os modelos foram desenvolvidos pelo programa SolidWorks 2010 (3Dtech, São Paulo, Brasil). Forças oblíquas (100 N) foram aplicadas na face palatal das coroas. A interface osso-implante foi considerada perfeitamente integrada. Máxima e mínima tensão principal foram avaliadas no osso cortical e medular. A análise numérica foi realizada através do programa ANSYS Workbenck 10,0 (Swanson Analysis System, Houston, Pa). Resultados: No osso cortical, os maiores valores de tensão foram observados para R (48,8 MPa), seguido de S (48,5 MPa). Para o osso medular, os maiores valores de tensão foram observados no modelo S (3,66 MPa), seguido por R (1,51 MPa). Conclusão: O modelo switching apresentou comportamento biomecânico semelhante ao modelo de plataforma regular na análise do osso cortical. Enquanto que no osso medular, o modelo switching transmitiu mais tensão óssea do que o modelo Regular.

Stress distribution on dentin-cement-post interface varying root canal and glass fiber post diameters. A three-dimensional finite element analysis based on micro-CT data

Objective: The aim of the present study was to analyze the influence of root canal and glass fiber post diameters on the biomechanical behavior of the dentin/cement/post interface of a root-filled tooth using 3D finite element analysis. Material and Methods: Six models were built using micro-CT imaging data and SolidWorks 2007 software, varying the root canal (C) and the glass fiber post (P) diameters: C1P1-C=1 mm and P=1 mm; C2P1-C=2 mm and P=1 mm; C2P2-C=2 mm and P=2 mm; C3P1-C=3 mm and P=1 mm; C3P2-C=3 mm and P=2 mm; and C3P3-C=3 mm and P=3 mm. The numerical analysis was conducted with ANSYS Workbench 10.0. An oblique force (180 N at 45º) was applied to the palatal surface of the central incisor. The periodontal ligament surface was constrained on the three axes (x=y=z=0). Maximum principal stress (σmax) values were evaluated for the root dentin, cement layer, and glass fiber post. Results: The most evident stress was observed in the glass fiber post at C3P1 (323 MPa), and the maximum stress in the cement layer occurred at C1P1 (43.2 MPa). The stress on the root dentin was almost constant in all models with a peak in tension at C2P1 (64.5 MPa). CONCLUSION: The greatest discrepancy between root canal and post diameters is favorable for stress concentration at the post surface. The dentin remaining after the various root canal preparations did not increase the stress levels on the root. .

Stress distribution on dentin-cement-post interface varying root canal and glass fiber post diameters. A three-dimensional finite element analysis based on micro-CT data.

OBJECTIVE: The aim of the present study was to analyze the influence of root canal and glass fiber post diameters on the biomechanical behavior of the dentin/cement/post interface of a root-filled tooth using 3D finite element analysis. MATERIAL AND METHODS: Six models were built using micro-CT imaging data and SolidWorks 2007 software, varying the root canal (C) and the glass fiber post (P) diameters: C1P1-C=1 mm and P=1 mm; C2P1-C=2 mm and P=1 mm; C2P2-C=2 mm and P=2 mm; C3P1-C=3 mm and P=1 mm; C3P2-C=3 mm and P=2 mm; and C3P3-C=3 mm and P=3 mm. The numerical analysis was conducted with ANSYS Workbench 10.0. An oblique force (180 N at 45º) was applied to the palatal surface of the central incisor. The periodontal ligament surface was constrained on the three axes (x=y=z=0). Maximum principal stress (σ(max)) values were evaluated for the root dentin, cement layer, and glass fiber post. RESULTS: The most evident stress was observed in the glass fiber post at C3P1 (323 MPa), and the maximum stress in the cement layer occurred at C1P1 (43.2 MPa). The stress on the root dentin was almost constant in all models with a peak in tension at C2P1 (64.5 MPa). CONCLUSION: The greatest discrepancy between root canal and post diameters is favorable for stress concentration at the post surface. The dentin remaining after the various root canal preparations did not increase the stress levels on the root.

Regular and switching platform: bone stress analysis with varying implant diameter.

The aim of this study was to evaluate stress distribution of the peri-implant bone by simulating the biomechanical influence of implants with different diameters of regular or platform switched connections by means of 3-dimensional finite element analysis. Five mathematical models of an implant-supported central incisor were created by varying the diameter (5.5 and 4.5 mm, internal hexagon) and abutment platform (regular and platform switched). For the cortical bone, the highest stress values (σmax and σvm) were observed in situation R1, followed by situations S1, R2, S3, and S2. For the trabecular bone, the highest stress values (σmax) were observed in situation S3, followed by situations R1, S1, R2, and S2. The influence of platform switching was more evident for cortical bone than for trabecular bone and was mainly seen in large platform diameter reduction.

Restaurações estéticas cerâmicas e endocrowns na reabilitação de dentes posteriores / Esthetic restorations ceramics and endocrowns in the posterior teeth rehabilitation

A utilização de restaurações estéticas em dentes posteriores tem aumentado significativamente nos últimos anos. Restaurações inlays, onlays, overlays e endocrowns possibilitam recuperar a estética e a resistência dos dentes posteriores, além de constituírem alternativas mais conservadoras quando comparadas às coroas totais. O presente trabalho descreve os procedimentos clínicos para a reabilitação dos dentes posteriores por meio de restaurações indiretas confeccionadas com cerâmica à base de dissilicato de lítio. Esse tipo de abordagem resulta em restaurações altamente estéticas, mecanicamente resistentes e funcionais

The main cause of patients withdrawal in relation to the demand for this procedure or suspension of bleaching is the dental sensitivity. For this, both modifcations in bleaching agents as clinical strategies have been proposed to eliminate and/or control this unwanted symptoms without affecting the fnal esthetic result. The present case report shows the association of several strategies to decrease the dental bleaching sensitivity caused by 16% peroxide carbamide gel for at-home bleaching. The results showed that the patient was very satisfed with the bleaching result and there was no record of sensitivity during the bleaching procedure.

Short implant to support maxillary restorations: bone stress analysis using regular and switching platform.

PURPOSE: The aim of this study was to evaluate stress distribution on peri-implant bone simulating the influence of implants with different lengths on regular and switching platforms in the anterior maxilla by means of three-dimensional finite element analysis. MATERIALS AND METHODS: Four mathematical models of a central incisor supported by an external hexagon implant (diameter, 5.0 mm) were created, varying the length (15.0 mm for long implants [L] and 7.0 mm for short implants [S]) and the diameter of the abutment platform (5.0 mm for regular models [R] and 4.1 mm for switching models [S]). The models were created using the Mimics 11.11 (Materialise) and SolidWorks 2010 (Inovart) software. Numerical analysis was performed using ANSYS Workbench 10.0 (Swanson Analysis System). Oblique forces (100 N) were applied to the palatine surface of the central incisor. The bone/implant interface was considered perfectly integrated. Maximum (σ(max)) and minimum (σ(min)) principal stress values were obtained. RESULTS: For the cortical bone, the highest stress values (σ(max)) were observed in the SR (73.7 MPa) followed by LR (65.1 MPa), SS (63.6 MPa), and LS (54.2 MPa). For the trabecular bone, the highest stress values (σ(max)) were observed in the SS (8.87 MPa) followed by the SR (8.32 MPa), LR (7.49 MPa), and LS (7.08 MPa). CONCLUSIONS: The influence of switching platform was more evident for the cortical bone in comparison with the trabecular bone for the short and long implants. The long implants showed lower stress values in comparison to the short implants, mainly when the switching platform was used.

Regular and platform switching: bone stress analysis varying implant type.

PURPOSE: This study aimed to evaluate stress distribution on peri-implant bone simulating the influence of platform switching in external and internal hexagon implants using three-dimensional finite element analysis. MATERIALS AND METHODS: Four mathematical models of a central incisor supported by an implant were created: External Regular model (ER) with 5.0 mm × 11.5 mm external hexagon implant and 5.0 mm abutment (0% abutment shifting), Internal Regular model (IR) with 4.5 mm × 11.5 mm internal hexagon implant and 4.5 mm abutment (0% abutment shifting), External Switching model (ES) with 5.0 mm × 11.5 mm external hexagon implant and 4.1 mm abutment (18% abutment shifting), and Internal Switching model (IS) with 4.5 mm × 11.5 mm internal hexagon implant and 3.8 mm abutment (15% abutment shifting). The models were created by SolidWorks software. The numerical analysis was performed using ANSYS Workbench. Oblique forces (100 N) were applied to the palatal surface of the central incisor. The maximum (σ(max)) and minimum (σ(min)) principal stress, equivalent von Mises stress (σ(vM)), and maximum principal elastic strain (ε(max)) values were evaluated for the cortical and trabecular bone. RESULTS: For cortical bone, the highest stress values (σ(max) and σ(vm) ) (MPa) were observed in IR (87.4 and 82.3), followed by IS (83.3 and 72.4), ER (82 and 65.1), and ES (56.7 and 51.6). For ε(max), IR showed the highest stress (5.46e-003), followed by IS (5.23e-003), ER (5.22e-003), and ES (3.67e-003). For the trabecular bone, the highest stress values (σ(max)) (MPa) were observed in ER (12.5), followed by IS (12), ES (11.9), and IR (4.95). For σ(vM), the highest stress values (MPa) were observed in IS (9.65), followed by ER (9.3), ES (8.61), and IR (5.62). For ε(max) , ER showed the highest stress (5.5e-003), followed by ES (5.43e-003), IS (3.75e-003), and IR (3.15e-003). CONCLUSION: The influence of platform switching was more evident for cortical bone than for trabecular bone, mainly for the external hexagon implants. In addition, the external hexagon implants showed less stress concentration in the regular and switching platforms in comparison to the internal hexagon implants.

Influence of crown ferrule heights and dowel material selection on the mechanical behavior of root-filled teeth: a finite element analysis.

PURPOSE: This study used the 3D finite element (FE) method to evaluate the mechanical behavior of a maxillary central incisor with three types of dowels with variable heights of the remaining crown structure, namely 0, 1, and 2 mm. MATERIALS AND METHODS: Based on computed microtomography, nine models of a maxillary central incisor restored with complete ceramic crowns were obtained, with three ferrule heights (0, 1, and 2 mm) and three types of dowels (glass fiber = GFD; nickel-chromium = NiCr; gold alloy = Au), as follows: GFD0--restored with GFD with absence (0 mm) of ferrule; GFD1--similar, with 1 mm ferrule; GFD2--glass fiber with 2 mm ferrule; NiCr0--restored with NiCr alloy dowel with absence (0 mm) of ferrule; NiCr1--similar, with 1 mm ferrule; NiCr2--similar, with 2 mm ferrule; Au0--restored with Au alloy dowel with absence (0 mm) of ferrule; Au1--similar, with 1 mm ferrule; Au2--similar, with 2 mm ferrule. A 180 N distributed load was applied to the lingual aspect of the tooth, at 45° to the tooth long axis. The surface of the periodontal ligament was fixed in the three axes (x = y = z = 0). The maximum principal stress (σ(max)), minimum principal stress (σ(min)), equivalent von Mises (σ(vM)) stress, and shear stress (σ(shear)) were calculated for the remaining crown dentin, root dentin, and dowels using the FE software. RESULTS: The σ(max) (MPa) in the crown dentin were: GFD0 = 117; NiCr0 = 30; Au0 = 64; GFD1 = 113; NiCr1 = 102; Au1 = 84; GFD2 = 102; NiCr2 = 260; Au2 = 266. The σ(max) (MPa) in the root dentin were: GFD0 = 159; NiCr0 = 151; Au0 = 158; GFD1 = 92; NiCr1 = 60; Au1 = 67; GFD2 = 97; NiCr2 = 87; Au2 = 109. CONCLUSION: The maximum stress was found for the NiCr dowel, followed by the Au dowel and GFD; teeth without ferrule are more susceptible to the occurrence of fractures in the apical root third.

Straight and angulated abutments in platform switching: influence of loading on bone stress by three-dimensional finite element analysis.

PURPOSE: In view of reports in the literature on the benefits achieved with the use of platform switching, described as the use of an implant with a larger diameter than the abutment diameter, the goal being to prevent the (previously) normal bone loss down to the first thread that occurs around most implants, thus enhancing soft tissue aesthetics and stability and the need for implant inclination due to bone anatomy in some cases, the aim of this study was to evaluate bone stress distribution on peri-implant bone, by using three-dimensional finite element analysis to simulate the influence of implants with different abutment angulations (0 and 15 degrees) in platform switching. METHODS: Four mathematical models of an implant-supported central incisor were created with varying abutment angulations: straight abutment (S1 and S2) and angulated abutment at 15 degrees (A1 and A2), submitted to 2 loading conditions (100 N): S1 and A1-oblique loading (45 degrees) and S2 and A2-axial loading, parallel to the long axis of the implant. Maximum (σmax) and minimum (σmin) principal stress values were obtained for cortical and trabecular bone. RESULTS: Models S1 and A1 showed higher σmax in cortical and trabecular bone when compared with S2 and A2. The highest σmax values (in MPa) in the cortical bone were found in S1 (28.5), followed by A1 (25.7), S2 (11.6), and A2 (5.15). For the trabecular bone, the highest σmax values were found in S1 (7.53), followed by A1 (2.87), S2 (2.85), and A2 (1.47). CONCLUSIONS: Implants with straight abutments generated the highest stress values in bone. In addition, this effect was potentiated when the load was applied obliquely.

Restabelecimento estético com laminados cerâmicos / Aesthetic excellency in ceramic venners

As coroas adesivas livres de metal promovem a estética e função; porém, para conseguir excelência estética com esses materiais indiretos, são necessários conhecimentos acerca de cor, forma, técnica restauradora e características de opacidade e translucidez. Através do relato de dois casos clínicos serão demonstradas todas as fases do tratamento desde o planejamento e diagnóstico até o preparo cavitário, moldagem e cimentação adesiva. O primeiro caso clínico aborda o restabelecimento do sorriso através de facetas de porcelana; e o segundo, a melhora estética anterior com associação de facetas e coroas livres de metal.

Cerâmicas em dentes anteriores: Parte I: indicações clínicas dos sistemas cerâmicos / Ceramics in anterior teeth: Part 1: clinical indications of the ceramic systems

A introdução de materiais livres de metal na odontologia restauradora, juntamente com o desenvolvimento das técnicas adesivas, tornou possível o uso de diversos sistemas cerâmicos em dentes anteriores. Nesse sentido, este artigo descreve a evolução dos sistemas IPS Empress (Ivoclar Vivadent AG, Liechtenstein), In-Ceram (Vita Zahnfabrik, Alemanha) e Procera AllCeram (Nobel Biocare, Suécia) na odontologia, apresentando suas características clínicas e laboratoriais, e destacando algumas particularidades de cada sistema.

Protocolo clínico para utilização de uma nova cerâmica vítrea reforçada por leucita / A clinical protocol in the use of a new glass ceramic reinforced by leucite

As cerâmicas dentárias, além de quimicamente estáveis, apresentam propriedades ópticas excelentes quando comparadas às estruturas dentárias, garantindo assim um posto especial no rol dos materiais restauradores estéticos. Porém, sua conhecida friabilidade limita seu uso, exigindo estratégias para sua proteção contra os estresses da mastigação. Assim, várias formas de reforço à sua estrutura estão descritas na literatura e aplicadas na Odontologia restauradora. O presente trabalho descreve a utilização clínica de um novo material cerâmico reforçado por leucita denominado IPS Empress Esthetic (Ivoclar Vivadent), através de cinco casos clínicos.