Repair technique for fractured implant-supported metal-ceramic restorations: a clinical report.

The fracture of porcelain structures have been related in either natural dentition or implant-supported restorations. Techniques using a composite resin or indirect methods can be used. This article presents a porcelain fracture on implant-supported metal-ceramic restoration. IPS Empress e.max laminate veneer restoration was used to repair the fracture. With this technique, it was possible to restore aesthetics and function, combined with low cost and patient satisfaction.

Candida albicans adherence to an acrylic resin modified by experimental photopolymerised coatings: an in vitro study.

PURPOSE: This study evaluated whether photopolymerised coatings containing zwitterion or hydrophilic monomers would reduce the adhesion of Candida albicans to an acrylic resin. MATERIALS AND METHODS: Disc-shaped samples (n = 468) were fabricated with rough or smooth surfaces. The samples did not receive any surface treatment (control) or were coated with one of the following experimental coatings (2-hydroxyethyl methacrylate - HE; 3-hydroxypropyl methacrylate - HP; and 2-trimethylammonium ethyl methacrylate chloride - T; and sulfobetaine methacrylate - S). The concentrations of the constituent monomers were 25, 30 or 35%. The water contact angles of the samples were measured, and half of the samples were exposed to saliva. The adherent yeast cells were counted after crystal violet staining. RESULTS: For the smooth samples, the groups S35, HP35 and HE35 showed significantly lower number of adhered Candida than control, in the absence of saliva. There were no significant differences among the experimental and control groups for the rough samples, but the saliva decreased the cell numbers for groups S25, S30 and HP30. The photoelectron spectroscopy analysis confirmed the changes in the chemical compositions of the experimental samples. CONCLUSIONS: The experimental photopolymerised coatings changed the chemical composition and decreased C. albicans adhesion in the groups S35, HP35 and HE35, suggesting that they should be further investigated.

Effect of experimental photopolymerized coatings on the hydrophobicity of a denture base acrylic resin and on Candida albicans adhesion.

OBJECTIVE: This study investigated the effect of experimental photopolymerized coatings, containing zwitterionic or hydrophilic monomers, on the hydrophobicity of a denture base acrylic resin and on Candida albicans adhesion. METHODS: Acrylic specimens were prepared with rough and smooth surfaces and were either left untreated (control) or coated with one of the following experimental coatings: 2-hydroxyethyl methacrylate (HE); 3-hydroxypropyl methacrylate (HP); and 2-trimethylammonium ethyl methacrylate chloride (T); and sulfobetaine methacrylate (S). The concentrations of these constituent monomers were 25%, 30% or 35%. Half of the specimens in each group (control and experimentals) were coated with saliva and the other half remained uncoated. The surface free energy of all specimens was measured, regardless of the experimental condition. C. albicans adhesion was evaluated for all specimens, both saliva conditioned and unconditioned. The adhesion test was performed by incubating specimens in C. albicans suspensions (1×10(7)cell/mL) at 37°C for 90min. The number of adhered yeasts were evaluated by XTT (2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-5-[{phenylamino}carbonyl]-2H-tetrazolium-hydroxide) method. RESULTS: For rough surfaces, coatings S (30 or 35%) and HP (30%) resulted in lower absorbance values compared to control. These coatings exhibited more hydrophilic surfaces than the control group. Roughness increased the adhesion only in the control group, and saliva did not influence the adhesion. The photoelectron spectroscopy analysis (XPS) confirmed the chemical changes of the experimental specimens, particularly for HP and S coatings. CONCLUSIONS: S and HP coatings reduced significantly the adhesion of C. albicans to the acrylic resin and could be considered as a potential preventive treatment for denture stomatitis.

Anterior tooth rehabilitation with frozen homogenous bone graft and immediately loaded titanium implant using computer-guided surgery.

Computed tomographic scanning is a precise, noinvasive surveying technique that enables the professionals to improve the precision of implant placement by building a prototype that allows the confection of surgical guides. The authors present a clinical case of anterior tooth rehabilitation with frozen homogenous bone graft and immediately loaded titanium implant using computer-guided surgery. A multislice computed tomography was realized, and a prototype was built. All the procedures were previously realized in the prototype before started in the patient. This technique allows a better surgical planning, makes the procedures more accurate, and reduces surgery time.

Effect of thermocycling on the flexural and impact strength of urethane-based and high-impact denture base resins.

OBJECTIVE: Mechanical properties of the acrylic resins used for denture fabrication may be influenced by water and temperature. Thus, the aim of this study was to evaluate the effect of thermocycling on the flexural and impact strength of a high-impact (Lucitone 199) and a urethane-based denture material (Eclipse). MATERIALS AND METHODS: Flexural strength (64 × 10 × 3.3 mm) and impact strength (60 × 6 × 4 mm) specimens were made following the manufacturers' instructions and assigned to two groups (n = 10): control (C) - not thermocycled - and T - thermocycled (5000 cycles between 5 and 55°C). Specimens were submitted to three-point bending and Charpy impact tests. RESULTS: Flexural strength (MPa) and impact strength (kJ/m(2)) data were analysed with two-way anova (p = 0.05). The flexural strength of material Eclipse (C, 136.5; T, 130.7) was significantly higher than that of resin Lucitone 550 (C, 99.4; T, 90.1). Material Eclipse exhibited significantly higher impact strength (C, 6.9; T, 5.3) than the resin Lucitone 550 (C, 3.5; T, 3.0). For both materials, a significant decrease in flexural and impact strengths was observed when the specimens were thermocycled. CONCLUSION: Flexural and impact strengths were higher for Eclipse than for Lucitone 550, in both groups. Thermocycling decreased the flexural and impact strengths of Eclipse and Lucitone 550.

Impact strength of denture base and reline acrylic resins subjected to long-term water immersion.

Water may influence the mechanical properties of the acrylic resins. Thus, the effect of water storage on the impact strength (IS) of one denture base (Lucitone 550 - L) and four reline resins (Tokuyama Rebase II - T; UfiGel Hard - U; Kooliner - K; New Truliner - NT) was evaluated. Bars of L were made (60 x 6 x 2 mm) and relined (2 mm) with T, U, K, NT and L. Intact specimens of each material (60 x 6 x 4 mm) were also fabricated for comparative purposes. Specimens were submitted to Charpy impact tests without water storage (control) and after immersion in water for 7, 90 and 180 days. Data (kJ/m(2)) analyzed by two-way ANOVA and Tukey's test (p=0.05) revealed that after 90 days, U exhibited an increase in the IS (0.93) compared to 7 days (0.58). K (1.48) and L/K (7.21) exhibited a decrease at the 7-day period (1.01 and 3.23, respectively). NT (0.60) showed an increase in the IS after 180 days (1.52), whereas L/NT (7.70) showed a decrease (3.17). Water immersion improved the IS of U and NT, and decreased the IS of K, L/K, and L/NT. Water may affect differently the IS of acrylic resins and, consequently, the resistance to fracture of relined denture bases.

Impact strength of denture base and reline acrylic resins subjected to long-term water immersion

Water may influence the mechanical properties of the acrylic resins. Thus, the effect of water storage on the impact strength (IS) of one denture base (Lucitone 550 - L) and four reline resins (Tokuyama Rebase II - T; UfiGel Hard - U; Kooliner - K; New Truliner - NT) was evaluated. Bars of L were made (60 x 6 x 2 mm) and relined (2 mm) with T, U, K, NT and L. Intact specimens of each material (60 x 6 x 4 mm) were also fabricated for comparative purposes. Specimens were submitted to Charpy impact tests without water storage (control) and after immersion in water for 7, 90 and 180 days. Data (kJ/m²) analyzed by two-way ANOVA and Tukey's test (p=0.05) revealed that after 90 days, U exhibited an increase in the IS (0.93) compared to 7 days (0.58). K (1.48) and L/K (7.21) exhibited a decrease at the 7-day period (1.01 and 3.23, respectively). NT (0.60) showed an increase in the IS after 180 days (1.52), whereas L/NT (7.70) showed a decrease (3.17). Water immersion improved the IS of U and NT, and decreased the IS of K, L/K, and L/NT. Water may affect differently the IS of acrylic resins and, consequently, the resistance to fracture of relined denture bases.

A água pode influenciar as propriedades mecânicas das resinas acrílicas. Assim, o efeito do armazenamento em água na resistência ao impacto (RI) de uma resina para base de prótese (Lucitone 550-L) e quatro materiais reembasadores (Tokuyama Rebase II-T; UfiGel Hard-U; Kooliner-K; New Truliner-NT) foi avaliado. Barras da resina L foram confeccionadas (60 x 6 x 2 mm) e reembasadas (2 mm) com T, U, K, NT e L. Amostras não reembasadas de cada material também foram confeccionadas (60 x 6 x 4 mm) para fins comparativos. As amostras foram submetidas aos testes de impacto tipo Charpy sem armazenamento (controle) e após imersão em água por 7, 90 e 180 dias. Os resultados (kJ/m²) analisados por meio de ANOVA dois fatores e teste de Tukey (p=0,05) revelaram que, após 90 dias, U exibiu aumento na RI (0,93) comparado com 7 dias (0,58). K (1,48) e L/K (7,21) exibiram diminuição no período de 7 dias (1,01 e 3,23, respectivamente). NT (0,60) apresentou aumento na RI após 180 dias (1,52), enquanto L/NT (7,70) apresentou redução (3,17). A imersão em água melhorou a RI de U e NT e diminuiu a RI de K, L/K, e L/NT. A água pode afetar de maneira diversa a RI das resinas acrílicas e, consequentemente, a resistência à fratura das bases de próteses reembasadas.

Propriedade antifúngica de resina para base de prótese modificada com nanopartículas de prata / Antifungal properties of a denture base resin modified with silver nanoparticles

Apesar do uso de drogas antifúngicas no tratamento da estomatite protética, freqüentemente a infecção é persistente e a resistência microbiana tem sido observada nos biofilmes de Candida albicans. Dessa forma, existe a necessidade de se desenvolver outros agentes antimicrobianos tais como as nanopartículas de prata (AgNPs). Assim, o objetivo deste estudo foi avaliar o efeito de uma solução preparada de AgNPs sobre C. albicans em suspensão. Além disso, os efeitos da incorporação de diferentes concentrações da solução de AgNPs em uma resina acrílica para base de prótese e o armazenamento por períodos de até 180 dias no ângulo de contato, adesão e formação de biofilme foram avaliados. A solução de AgNPs foi sintetizada por meio de redução química utilizando borohidreto de sódio (NaBH4) como agente redutor e polivinil álcool (PVA) como estabilizante, e foi caracterizada utilizando espectroscopia UV-visível (UV-vis), espectrometria de infravermelho por transformada de Fourier (FTIR) e espalhamento de luz dinâmico (DLS). A susceptibilidade antimicrobiana da solução de AgNPs de diferentes concentrações (de 1000 a 20 ppm) foi avaliada em C. albicans suspensão (ATCC 90028). A solução de AgNPs foi também misturada com o pó da resina para produzir resinas acrílicas com AgNPs incorporadas nas concentrações finais de 1000, 750, 500, 250 e 30 ppm. Resina sem AgNPs foi utilizada como controle. Amostras em forma de discos (13 × 2 mm) de cada concentração (n=72) foram preparadas e armazenadas em PBS estéril por 0, 7, 90 e 180 dias (n=18). Após esses períodos, os ângulos de contato foram mensurados em um goniômetro. A seguir, 9 amostras de cada concentração foram utilizadas para o teste de aderência de C. albicans (90 minutos de incubação), e 9 para o teste de formação de biofilme (48 horas de incubação). Os efeitos da solução de AgNPs e das amostras de resina acrílica para base de prótese na C. albicans foram avaliados utilizando o método de redução do XTT. O método de redução química descrito neste estudo possibilitou a obtenção de uma solução de AgNPs com, aproximadamente, 9 nm, que demonstrou alta Propriedade antifúngica de resina para base de prótese modificada com nanopartícula de prata atividade antifúngica contra C. albicans, em todas as concentrações avaliadas. Após a incorporação da solução de AgNPs à resina acrílica para base de prótese, não houve efeito significativo contra C. albicans, em todas as concentrações avaliadas. A incorporação da solução de AgNPs à resina acrílica proporcionou redução dos valores médios de ângulo de contato; entretanto, não houve efeito significativo na aderência ou na formação de biofilme de C. albicans. Houve aumento dos valores de ângulo de contato e de absorbância obtidos nos testes de adesão e formação de biofilme após o armazenamento dos corpos-de-prova por períodos de 90 e 180 dias

Despite the use of antifungal drugs to treat denture stomatitis, infection is often persistent and antifungal resistance has been observed in C. albicans biofilms. Therefore, there is a need to develop alternative antimicrobial agents such as silver nanoparticles (AgNPs). Thus, the objective of this study was to evaluate the effect of a prepared AgNPs aqueous solution against C. albicans suspension. Additionally, the effects of incorporation of different concentrations of the AgNPs solution into a denture base acrylic resin and storage for up to 180 days on the contact angle, C. albicans adhesion and biofilm formation were evaluated. The AgNPs solution was synthesized by chemical reduction using sodium borohydride as reducing agent and polyvinyl alcohol as stabilizer, and was characterized by UV-visible spectroscopy, Fourier transform infrared spectroscopy and Dynamic Light Scattering. The antimicrobial susceptibility of AgNPs solution of different concentrations (from 1000 to 20 ppm) was performed against C. albicans suspension (ATCC 90028). The AgNPs solution was also mixed with the acrylic powder to produce silver-incorporated acrylic resins at the final concentrations of 1000, 750, 500, 250 and 30 ppm. Resin without AgNPs was used as control. Disk-shaped samples (13 × 2 mm) of each concentration (n=72) were prepared and stored in sterile PBS for 0, 7, 90 and 180 days (n=18). After the storage periods, the contact angles were measured in a goniometer. Then, 9 samples of each concentration were used for the C. albicans adherence assay (90 minutes of incubation), and 9 for the biofilm formation assay (48 hours of incubation). The effects of the AgNPs solution and the denture base acrylic resin samples on C. albicans were evaluated using the XTT reduction assay. The AgNPs solution, with nanoparticles of, aproximately 9 nm, demonstrated high antimicrobial activity in all tested concentrations. After the AgNPs were incorporated into the denture base acrylic resin, no effect was observed against C. albicans. The incorporation of the AgNPs reduced the contact angles of the denture base acrylic resin; however no effect on the C. albicans adherence and biofilm formation was observed. There was significant increase in the mean contact angles and mean absorbance values obtained in the C. albicans adherence and biofilm formation assays, after the specimens were stored for 90 and 180 days