Marginal adaptation and fracture resistance of virgilite-based occlusal veneers with varying thickness.

STATEMENT OF PROBLEM: CAD/CAM occlusal veneers have been developed for minimally invasive prosthetic restoration of eroded teeth. Marginal adaptation and fracture resistance are crucial for the long-term survivability and clinical success of such restorations. Virgilite-based lithium disilicate glass-ceramic is a newly introduced material with claims of high strength. However, constructing occlusal veneers from this material of varying thickness has not been investigated. PURPOSE: The current study aimed to assess the impact of CAD/CAM occlusal veneer thickness and materials on marginal adaptation and fracture resistance. MATERIALS AND METHODS: Thirty-two occlusal veneers were constructed and divided into two groups (n = 16) based on the CAD/CAM material into Brilliant Crios and CEREC Tessera. Each group was further subdivided into two subgroups (n = 8) according to the thickness: 0.6 and 0.9 mm. Occlusal veneers were bonded to epoxy resin dies. The marginal gap was evaluated before and after thermodynamic aging. Fracture resistance and failure mode were evaluated for the same samples after aging. Marginal adaptation was analyzed using the Mann-Whitney U test. Fracture resistance was analyzed using Weibull analysis (α = 0.05). RESULTS: The marginal gap was significantly increased following thermodynamic aging for tested groups (P < 0.001). CEREC Tessera showed a significantly higher marginal gap than Brilliant Crios before and after aging for both thicknesses (P < 0.05). CEREC Tessera recorded lower significant fracture load values compared to Brilliant Crios (P < 0.05). CONCLUSIONS: Both CEREC Tessera and Brilliant Crios demonstrated clinically accepted marginal gap values. All groups showed fracture resistance values higher than the average masticatory forces in the premolar region except for 0.6 mm CEREC Tessera. CLINICAL IMPLICATIONS: Reinforced composite occlusal veneers demonstrated more favorable outcomes in terms of marginal gap and fracture resistance at both tested thicknesses compared to virgilite-based lithium disilicate glass-ceramic. Additionally, caution should be exercised during the construction of occlusal veneers from virgilite-based lithium disilicate glass-ceramic with reduced thickness.

Esthetic patient satisfaction, marginal bone loss and peri-implant tissue success in esthetic zone: systematic review / Satisfação estética do paciente, perda óssea marginal e sucesso do tecido peri-implantar na zona estética: revisão sistemática

Increased patient demands for highly esthetic implant superstructure in the anterior esthetic zone has increased in the last decades. Moreover, the absence of periodontal ligament in implant supported prosthesis causes forces to be transferred without cushioning effect to the alveolar bone, resulting in increased marginal bone loss (MBL) and influence the heath of peri-implant tissue. Evaluate the available evidence on the effect implant superstructure and it consequences on patient satisfaction, MBL, bleeding on probing (BOP) and probing depth (PD). A protocol of electronic and hand research was performed for English based researches comparing implants inserted in the esthetic zone with all ceramic superstructure: "Will the use of different types of all ceramic superstructure show different esthetic patient satisfaction, marginal bone loss, bleeding on probing and probing depth? Thirteen publications from one thousand one hundred and sixteen research studies were included. This systematic review showed that all ceramic implant superstructure was a versatile treatment option with higher esthetic patient satisfaction and better color of peri-implant mucous especially in patients having thin biotype. On the other hand there wasn't significant difference in MBL, PD and BOP compared to other conventional implant superstructure. More randomized controlled clinical trials with bigger samples are needed to confirm our findings. All ceramic implant superstructure is versatile and highly esthetic treatment option for implant placed in the anterior esthetic zone.(AU)

A demanda do paciente por superestruturas de implante altamente estéticas na zona anterior aumentou nas últimas décadas. Além disso, a ausência de ligamento periodontal em próteses implantossuportadas faz com que as forças sejam transferidas para o osso alveolar sem amortecimento, resultando em aumento da perda óssea marginal (MBL) e influenciando na saúde do tecido peri-implantar. Avaliar as evidências disponíveis sobre o efeito da superestrutura do implante e suas consequências na satisfação do paciente, perda óssea marginal, sangramento à sondagem (SS) e profundidade de sondagem (PS). Um protocolo de pesquisa eletrônica e manual foi realizado para a análise de artigos em inglês comparando implantes com toda a superestrutura em cerâmica inseridos na zona estética: "O uso de diferentes tipos de superestrutura em cerâmica mostrará diferentes níveis de satisfação estética do paciente, perda óssea marginal, sangramento em profundidade de sondagem e sondagem?". Foram selecionadas 1116 publicações e apenas treze estudos foram incluídos na análise final. Esta revisão sistemática mostrou que toda superestrutura do implante em cerâmica foi uma opção de tratamento versátil, com maior satisfação estética do paciente e melhor coloração da mucosa peri-implantar, especialmente em pacientes com biótipo fino. Por outro lado, não houve diferença significativa em MBL, PS e SS em comparação com outras superestruturas de implantes convencionais. Porém, mais ensaios clínicos controlados randomizados com amostras maiores são necessários para confirmar nossos achados. Implicações clínicas: Toda superestrutura do implante em cerâmica é uma opção de tratamento versátil e altamente estética para implantes colocados na zona anterior (AU)

One-year clinical evaluation of IPS Empress CAD versus polished Celtra Duo ceramic Laminate veneers (randomized controlled clinical trial) / Avaliação clínica de um ano de IPS Empress CAD versus laminados de cerâmica Celtra Duo polidos (ensaio clínico randomizado controlado)

Objective: To evaluate fracture resistance and survival rate of IPS Empress CAD versus Polished Celtra Duo ceramic laminate veneers. Material and Methods:Thirty-six ceramic laminate veneers were fabricated for maxillary anterior teeth. The patients were divided into two groups according to the material Group 1(control group) fabricated from IPS Empress CAD laminate veneers and group 2 (intervention group) fabricated from Polished Celtra Duo laminate veneers. Standardized the same preparation with butt joint design and chamfer finish line located supra gingival were performed for all the teeth. The fabrication of the veneers was performed using Cad\Cam (Ceramill motion) machine, with software (Exocad). The veneers surfaces were treated and silanated according to the manufacture instruction of each ceramic and enamel surfaces were etched where total etch adhesive protocol was obeyed using BISCO. Follow up sessions were done every two months up to one year for each patient using dental probe and operator vision to evaluate the fracture, survival rate, marginal adaptation, sensitivity and caries. according to USPHS criteria (United States Public Health Service). This was performed by an experienced, blinded investigator. Results: Fracture resistance, marginal adaptation, retention, caries and sensitivity were evaluated according to the criteria of USPHS and we found there is no significant difference as both groups scaled zero score. Conclusion: Both IPS Empress Cad and Polished Celtra Duo laminate veneers revealed successful clinical performance in terms of fracture resistance, marginal adaptation, retention, and sensitivity after one year follow up period (AU)

Objetivo: Avaliar a resistência à fratura e a taxa de sobrevivência de laminados de cerâmica IPS Empress CAD versus Celtra Duo polidos. Material e Métodos: Trinta e seis facetas cerâmicas laminadas foram confeccionadas para dentes anteriores superiores. Os pacientes foram divididos em dois grupos de acordo com o material Grupo 1 (grupo controle) confeccionado com laminados IPS Empress CAD e grupo 2 (grupo intervenção) confeccionado com laminados Celtra Duo polidos. A mesma forma de preparo e acabamento de chanfro localizado supra-gengival padronizados foram realizados para todos os dentes. A confecção das facetas foi realizada em máquina Cad \ Cam (Ceramill motion), com software (Exocad). As superfícies laminadas foram tratadas e silanizadas de acordo com as instruções do fabricante de cada cerâmica e as superfícies de esmalte foram condicionadas seguindo o protocolo adesivo de condicionamento ácido total com BISCO. Sessões de acompanhamento foram realizadas a cada dois meses durante um ano para cada paciente usando sonda exploradora e visão do operador para avaliar a fratura, taxa de sobrevivência, adaptação marginal, sensibilidade e cárie; de acordo com os critérios USPHS (Serviço de Saúde Pública dos Estados Unidos). Isso foi realizado por um investigador experiente e cego. Resultados: a resistência à fratura, adaptação marginal, retenção, cárie e sensibilidade foram avaliadas de acordo com os critérios da USPHS e não encontramos diferença significativa, pois ambos os grupos escalonaram pontuação zero. Conclusão: As facetas laminadas IPS Empress Cad e Celtra Duo polido revelaram desempenho clínico bem-sucedido em termos de resistência à fratura, adaptação marginal, retenção e sensibilidade após um período de acompanhamento de um ano. (AU)

Effect of obturating systems, dowel materials, and adhesive luting techniques on the resistance to fracture of endodontically treated teeth.

PURPOSE: The aim of this study was to assess the role of obturating systems, dowel materials, and adhesive techniques on the resistance to fracture of endodontically treated teeth. MATERIAL AND METHODS: Eighty maxillary central incisors were selected and randomly divided into two groups according to the obturating system (n = 40); group I: gutta-percha and Roeko sealer; group II: RealSeal. Both groups were further subdivided into two subgroups; subgroup A: using ceramic dowels (Cosmopost); subgroup B using fiber dowels (Easy Post). Each subgroup was assigned to two divisions according to the adhesive luting technique; division V (total-etch) Variolink II resin cement; division U (self-adhesive) RelyX Unicem. Composite core build-up was made using a core former. Each specimen was loaded 2 mm from its incisal edge on the palatal side at a 135° angle with the long axis of the tooth using a universal testing machine with a load cell of 5 KN at a crosshead speed of 0.5 mm/min until fracture. Failure loads were recorded in N. Scanning electron microscopic examination at the dentin/resin interface (1000x) was performed. Three-way ANOVA was used to test the effect of obturating system, dowel material, adhesive technique, and their interactions (obturating system * dowel material, obturating system * adhesive, dowel material * adhesive, obturating system * dowel material * adhesive). Duncan's test was used for pairwise comparison. The significance level was set at p≤ 0.05. Statistical analysis was performed with SPSS 16.0. RESULTS: The mean resistance to fracture (617.4 N) was statistically significantly higher in the ceramic dowel with gutta-percha and Variolink (GP/C/V) group than in the other groups. The RealSeal and RelyX fiber dowel group's mean resistance was the lowest and was significantly lower than the other groups. CONCLUSIONS: In this study, three factors played a part in enhancing the resistance to fracture of endodontically treated teeth. High resistance to fracture was achieved when ceramic dowels were luted with total-etch technique in gutta-percha-obturated teeth.

Alternative pretreatment modalities with a self-adhesive system to promote dentin/alloy shear bond strength.

PURPOSE: The aim of this study was to evaluate alternative pretreatment modalities to enhance the dentin/alloy shear bond strength using a self-etch adhesive system. MATERIAL AND METHODS: Ninety discs were fabricated and divided into three groups (n = 30). The discs of the first group were cast in gold palladium (Au-Pd); those of the second group were cast in palladium silver alloy (Pd-Ag); the discs of third group were cast in nickel chromium alloy (Ni-Cr). Each group was further divided into three subgroups (n = 10) according to the dentin pretreatment used to lute the discs. Subgroup U (no pre-treatment): Rely X Unicem resin cement. Subgroup GU: G-Bond then Rely X Unicem. Subgroup ZU: Zinc-Zeolite pretreatment then Rely X Unicem. Shear bond strength was determined using a compressive mode of force applied at the dentin/alloy interface using a monobevelled chisel-shaped metallic rod. Data were collected and statistically analyzed to assess the effect of alloy type, pretreatment modality, and their interactions on the shear bond strength. Scanning electron microscopic examination (1000x) at the dentin/resin interface was performed. Two-way ANOVA was used in testing significance for the effect of pretreatment, alloy, and their interaction. Duncan's post hoc test was used for pairwise comparison between the means when the ANOVA test was significant. The significance level was set at p< or = 0.05. Statistical analysis was performed with SPSS 15.0. RESULTS: Regarding the pretreatment modality, the mean shear bond strength and 95% CI of subgroups ZU (18.00 MPa; 16.8 to 19.2) and GU (16.91 MPa; 15.4 to 18.4) were significantly higher than subgroup U (12.81 MPa; 11.4 to 14.2). Regarding the alloy type, the mean shear bond strength and 95% CI of Ni-Cr groups (18.39 MPa; 16.9 to 19.9) were significantly higher than Au-Pd (15.33 MPa; 13.8 to 16.8) and Pd-Ag (13.99 MPa; 12.3 to 15.7). CONCLUSIONS: Pretreatment of dentin with G-Bond and Zinc Zeolite improved the dentin/alloy shear bond strength. Base metal alloys provided superior bond strength values with any adhesive modality compared to noble alloys. Treatment of the dentin surface prior to the application of a self-adhesive system is of great importance to enhancement of the dentin/alloy bond strength.

Effect of artificial saliva storage on microhardness and fracture toughness of a hydrothermal glass-ceramic.

PURPOSE: This study evaluated the effect of artificial saliva storage on the hardness, crack length, and fracture toughness of a glazed, polished, and bleached hydrothermal low-fusing glass-ceramic (Duceram LFC). MATERIALS AND METHODS: Forty ceramic discs were constructed. The discs were assigned to four groups (n = 10) according to their surface finish: Gp1 -- Autoglaze, Gp2 -- Autoglaze/ground/diamond-polished, Gp3 -- Overglaze, Gp4 -- Overglaze/ground/diamond-polished. Each group was further divided into two subgroups forming eight total subgroups (n = 5). Subgroup A was unbleached; Subgroup B was bleached. Testing was performed before and after 21 days of artificial saliva storage. Data were presented as means and standard deviation (SD). ANOVA was used, along with Duncan's post hoc test for pairwise comparison between the means when ANOVA test was found significant (p< or = 0.05). RESULTS: Surface treatments such as glazing, polishing, and bleaching, saliva storage, and the interaction between these variables had a statistically significant effect on mean values of microhardness, crack length, and fracture toughness of the specimens. There was a statistically significant increase in microhardness and fracture toughness mean values, while crack length values decreased after saliva storage. Polished specimens recorded the smallest crack lengths and fracture toughness, and highest hardness values before and after saliva storage. No difference in fracture toughness values was evident between glazed and polished specimens. Mean crack lengths decreased after saliva storage in all the tested specimens. Hardness values increased after saliva storage. The autoglazed group showed significantly higher fracture toughness, lower crack length, and microhardness than the overglazed group. CONCLUSIONS: Surface finishing procedures and artificial saliva storage had a statistically significant effect on mean values of microhardness, crack length, and fracture toughness. This in vitro study suggests that fracture toughness of ceramics may be affected by different surface treatments such as glazing, polishing, bleaching, or a combination; however, in this study Duceram LFC proved its self-healing property after 3-week storage in artificial saliva.