Chemistry of novel and contemporary resin-based dental adhesives.

The chemistry of resin-based dental adhesives is critical for its interaction with dental tissues and long-term bonding stability. Changes in dental adhesives composition influences the materials' key physical-chemical properties, such as rate and degree of conversion, water sorption, solubility, flexural strength and modulus, and cohesive strength and improves the biocompatibility to dental tissues. Maintaining a suitable reactivity between photoinitiators and monomers is important for optimal properties of adhesive systems, in order to enable adequate polymerisation and improved chemical, physical and biological properties. The aim of this article is to review the current state-of-the-art of dental adhesives, and their chemical composition and characteristics that influences the polymerisation reaction and subsequent materials properties and performance.

The influence of nanofillers on the properties of ethanol-solvated and non-solvated dental adhesives.

OBJECTIVES: The aim of this study was to evaluate the influence of different concentrations of nanofillers on the chemical and physical properties of ethanol-solvated and non-solvated dental adhesives. MATERIALS AND METHODS: Eight experimental adhesives were prepared with different nanofiller concentrations (0, 1, 2, and 4 wt%) and 2 solvent concentrations (0% and 10% ethanol). Several properties of the experimental adhesives were evaluated, such as water sorption and solubility (n = 5, 20 seconds light activation), real-time degree of conversion (DC; n = 3, 20 and 40 seconds light activation), and stability of cohesive strength at 6 months (CS; n = 20, 20 seconds light activation) using the microtensile test. A light-emitting diode (Bluephase 20i, Ivoclar Vivadent) with an average light emittance of 1,200 mW/cm2 was used. RESULTS: The presence of solvent reduced the DC after 20 seconds of curing, but increased the final DC, water sorption, and solubility of the adhesives. Storage in water reduced the strength of the adhesives. The addition of 1 wt% and 2 wt% nanofillers increased the polymerization rate of the adhesives. CONCLUSIONS: The presence of nanofillers and ethanol improved the final DC, although the DC of the solvated adhesives at 20 seconds was lower than that of the non-solvated adhesives. The presence of ethanol reduced the strength of the adhesives and increased their water sorption and solubility. However, nanofillers did not affect the water sorption and strength of the tested adhesives.

Retrospective study to evaluate the treatment of digital pulp lesions using a homodigital flap.

OBJECTIVE: To assess the homodigital flap surgical procedure, as well as the function of the finger, pain, sensation, esthetics, and patient satisfaction. METHOD: Retrospective analysis of records and questionnaires of patients who underwent this surgical technique between the months of May 2013 and October 2016. Eight were included in the study, with an average follow-up period of 23 months. Patients with digital pulp lesions of the thumbs and those who did not perform rehabilitation were excluded. All underwent the two-point discrimination test, the Semmes-Weinstein test, and range of motion evaluation. The age varied from 22 to 59 years (average of 32.9), six (75%) being male patients. RESULTS: Three patients (37.5%) had involvement of the right hand and five of the left (62.5%). Regarding the etiology, seven suffered injury and one a chemical burn. The average distance obtained from the two-point discrimination test was 7.3 mm. All patients who underwent the Semmes-Weinstein test obtained response to the purple filament. The average sum of the range of motion of the affected digit was 98.9%. The flap area was on average 294.4 mm2. The return to work averaged seven weeks. A positive Tinel sign was found in the donating area and two reported intolerance to cold. Partial or total necrosis of the flap was not observed. CONCLUSION: The homodigital flap technique presented satisfactory esthetics and functional results regarding feasibility, sensation, and digital mobility in pulp lesions.

OBJETIVO: Avaliar o procedimento cirúrgico de retalho homodigital, bem como a função do quirodáctilo, a dor, a sensibilidade, a estética e a satisfação do paciente. MÉTODO: Análise retrospectiva de prontuários e questionários de pacientes submetidos a essa técnica entre maio de 2013 e outubro de 2016. Oito pacientes foram incluídos no estudo, com uma média de seguimento de 23 meses. Foram excluídos os pacientes com lesões de polpa digital em polegares e os que não fizeram reabilitação. Todos os pacientes fizeram os testes de discriminação entre dois pontos, Semmes-Weinstein, e avaliação do arco de movimento. A idade variou entre 22 e 59 anos (média de 32,9), seis (75%) eram do sexo masculino. RESULTADOS: Três pacientes (37,5%) tiveram acometimento da mão direita e cinco (62,5%), da esquerda. Com relação à etiologia, sete sofreram lesão traumática e um sofreu queimadura química. A distância média obtida no teste de discriminação entre dois pontos foi de 7,3 mm. Todos os pacientes submetidos ao teste Semmes-Weinstein obtiveram resposta ao filamento de cor roxa. A média da somatória do arco de movimento do dígito acometido foi de 98,9%. A área do retalho foi em média de 294,4 mm2. O retorno ao trabalho foi em torno de sete semanas. Um apresentou sinal de Tinel positivo na área doadora e dois referiram intolerância ao frio. Não se observou necrose parcial ou total do retalho. CONCLUSÃO: : A técnica do retalho homodigital apresentou resultados estéticos e funcionais satisfatórios quanto à viabilidade, sensibilidade e mobilidade digital em lesões da polpa.

Retrospective study to evaluate the treatment of digital pulp lesions using a homodigital flap / Estudo retrospectivo para avaliação do tratamento de lesões da polpa digital com retalho homodigital

ABSTRACT Objective: To assess the homodigital flap surgical procedure, as well as the function of the finger, pain, sensation, esthetics, and patient satisfaction. Method: Retrospective analysis of records and questionnaires of patients who underwent this surgical technique between the months of May 2013 and October 2016. Eight were included in the study, with an average follow-up period of 23 months. Patients with digital pulp lesions of the thumbs and those who did not perform rehabilitation were excluded. All underwent the two-point discrimination test, the Semmes-Weinstein test, and range of motion evaluation. The age varied from 22 to 59 years (average of 32.9), six (75%) being male patients. Results: Three patients (37.5%) had involvement of the right hand and five of the left (62.5%). Regarding the etiology, seven suffered injury and one a chemical burn. The average distance obtained from the two-point discrimination test was 7.3 mm. All patients who underwent the Semmes-Weinstein test obtained response to the purple filament. The average sum of the range of motion of the affected digit was 98.9%. The flap area was on average 294.4 mm2. The return to work averaged seven weeks. A positive Tinel sign was found in the donating area and two reported intolerance to cold. Partial or total necrosis of the flap was not observed. Conclusion: The homodigital flap technique presented satisfactory esthetics and functional results regarding feasibility, sensation, and digital mobility in pulp lesions.

RESUMO Objetivo: Avaliar o procedimento cirúrgico de retalho homodigital, bem como a função do quirodáctilo, a dor, a sensibilidade, a estética e a satisfação do paciente. Método: Análise retrospectiva de prontuários e questionários de pacientes submetidos a essa técnica entre maio de 2013 e outubro de 2016. Oito pacientes foram incluídos no estudo, com uma média de seguimento de 23 meses. Foram excluídos os pacientes com lesões de polpa digital em polegares e os que não fizeram reabilitação. Todos os pacientes fizeram os testes de discriminação entre dois pontos, Semmes-Weinstein, e avaliação do arco de movimento. A idade variou entre 22 e 59 anos (média de 32,9), seis (75%) eram do sexo masculino. Resultados: Três pacientes (37,5%) tiveram acometimento da mão direita e cinco (62,5%), da esquerda. Com relação à etiologia, sete sofreram lesão traumática e um sofreu queimadura química. A distância média obtida no teste de discriminação entre dois pontos foi de 7,3 mm. Todos os pacientes submetidos ao teste Semmes-Weinstein obtiveram resposta ao filamento de cor roxa. A média da somatória do arco de movimento do dígito acometido foi de 98,9%. A área do retalho foi em média de 294,4 mm2. O retorno ao trabalho foi em torno de sete semanas. Um apresentou sinal de Tinel positivo na área doadora e dois referiram intolerância ao frio. Não se observou necrose parcial ou total do retalho. Conclusão: A técnica do retalho homodigital apresentou resultados estéticos e funcionais satisfatórios quanto à viabilidade, sensibilidade e mobilidade digital em lesões da polpa.

Effects of radiant exposure and wavelength spectrum of light-curing units on chemical and physical properties of resin cements.

OBJECTIVES: In this study, we evaluated the influence of different radiant exposures provided by single-peak and polywave light-curing units (LCUs) on the degree of conversion (DC) and the mechanical properties of resin cements. MATERIALS AND METHODS: Six experimental groups were established for each cement (RelyX ARC, 3M ESPE; LuxaCore Dual, Ivoclar Vivadent; Variolink, DMG), according to the different radiant exposures (5, 10, and 20 J/cm2) and two LCUs (single-peak and polywave). The specimens were made (7 mm in length × 2 mm in width × 1 mm in height) using silicone molds. After 24 hours of preparation, DC measurement was performed using Fourier transform infrared spectrometry. The same specimens were used for the evaluation of mechanical properties (flexural strength, FS; elastic modulus, E) by a three-point bending test. Data were assessed for normality, after which two-way analysis of variance (ANOVA) and post hoc Tukey's test were performed. RESULTS: No properties of the Variolink cement were influenced by any of the considered experimental conditions. In the case of the RelyX ARC cement, DC was higher when polywave LCU was used; FS and E were not influenced by the conditions evaluated. The LuxaCore cement showed greater sensitivity to the different protocols. CONCLUSIONS: On the basis of these results, both the spectrum of light emitted and the radiant exposure used could affect the properties of resin cements. However, the influence was material-dependent.

Enamel and dentin bond strength, interfacial ultramorphology and fluoride ion release of self-etching adhesives during a pH-cycling regime.

PURPOSE: This study evaluated the effects of pH cycling on fluoride release and bond strength of two self-etching adhesive systems to both enamel and dentin. The ultramorphology of the interfaces produced by the adhesive systems were also analyzed. MATERIALS AND METHODS: The buccal surfaces of bovine incisors were flattened to expose enamel and dentin, which were bonded with either Clearfil Protect Bond (CPB) or One-Up Bond F Plus (OBP). The bonded samples were prepared for microtensile bond strength (µTBS) testing, fluoride ion release, and transmission electron microscopy. pH cycling comprised demineralization (8 h/day) and remineralization (16 h/day) cycles for 8 days. The µTBS data were analyzed by two-way ANOVA, while fluoride release was analyzed using the Friedman and Wilcoxon tests. RESULTS: The adhesives presented similar bond strengths to enamel. However, the dentin bond strength of CPB was higher than that of OBP. pH cycling did not influence enamel or dentin µTBS. The amount of fluoride released from the bonded enamel and dentin was low and varied among the groups. The morphological evaluation showed that the thickness of the dentin hybrid layers was similar for both adhesives. CONCLUSION: The pH-cycling regime did not affect enamel or dentin bond strengths. In enamel, both the self-etching adhesives tested presented similar bond strengths, but in dentin, Clearfil Protect Bond showed higher dentin bonding than One-Up Bond F Plus.

Laminados cerâmicos: detalhes dessa abordagem minimamente invasiva / Ceramic veneers: details of this minimally invasive approach

A remodelação estética do sorriso pode ser realizada de duas maneiras: por meio de restaurações diretas, utilizando-se resinas compostas; ou com restaurações indiretas, utilizando-se coroas, facetas e/ou laminados cerâmicas. A abordagem minimamente invasiva, em foco nos últimos anos, tem-se mostrado efetiva na obtenção de excelentes resultados estéticos, com restaurações imperceptíveis. Desse modo, o presente trabalho demonstra, mediante relato de caso clínico, a abordagem minimamente invasiva, suas vantagens e desvantagens, utilizadas para a remodelação de dois laterais conoides, a qual influenciou a harmonia dos elementos anteriores e a estética do sorriso.

The aesthetic reshaping of the smile can be reached, basically, in two ways: direct restorations using composite resins; or using indirect restorations, such as full crowns and laminate veneers. A minimally invasive approach in focus in the last years, has obtained great results, with imperceptible restorations. In this way, this case report demonstrates the pros and cons of the minimal invasive approach for reshaping lateral conoid shaped incisors, which directly influenced the harmony of the maxillary anterior teeth and the aesthetics of the smile.

Effect of pre- heating on hardness of methacrylate- and silorane- based composites

AIM: To evaluate the effect of composite pre-heating on the microhardness of different monomer resin-based. MATERIALS AND METHOD: Circular specimens of methacrylate- and silorane-based composite resins pre-heated at 23, 39, and 55˚ C were carried out, and cured using a halogen light-curing unit at 650 mW/cm². After 24 h, the specimens were polished and Knoop hardness number (KHN) was measured using a microhardness tester with 50-g load for 15 s. The data were analyzed with ANOVA and Tukey's tests (α = 0.05). RESULTS: Top surface presented higher KHN than bottom, methacrylate-based composite showed higher KHN compared to silorane, and pre-heating increased the KHN of the composites tested. CONCLUSION: Pre-heating can be used to improve the microhardness of methracrylate- and silorane-based composites.

Efeito de cerâmicas odontológicas na passagem da luz emitida por aparelhos fotoativadores / Effect of dental ceramics on the transmittance of light emitted by curing units

Este estudo avaliou a influência de dois tipos de cerâmicas odontológicas (óxido de zircônio e dissilicato de lítio) na transmitância da luz emitida por diferentes aparelhos fotoativadores. Discos com 1 mm de espessura e 10 mm de diâmetro foram preparados a partir dos materiais restauradores indiretos: IPS e.Max Zircad (lvoclar Vivadent) e IPS e.Max (lvoclar Vivadent). Sobre os materiais protéticos foi aplicada a cerâmica à base de nanofluorapatita (IPS e.Max Ceram, Ivociar vivadent), com 1 mm de espessura. Cinco diferentes aparelhos fotoativadores foram testados: Arc Light 11 (AirTechniques), ColtoLux LED (Colténe Whaledent), Elipar Free Light 2 (3M ESPE), Astralis 10 (lvoclar Vivadent) e Ultralume 5 (Ultradent), sendo esse último utilizado no modo normal, apenas com luz azul ou luz violeta. A irradiância através dos diferentes materiais restauradores foi mensurada com um espectroradiômetro (DAS 2100, Labsphere) associado a um software especifico (Spectra Suite, Ocean Optics). Os dados foram submetidos à analise de variância de 2 fatores e teste de T ukey (p:s;O,05). A luz emitida pelo aparelho arco de plasma (Arc Light 11) mostrou maior passagem através dos materiais indiretos estudados, enquanto a luz violeta emitida pelo aparelho Ultralume 5 foi a mais bloqueada entre os aparelhos. A zircônia permitiu maior passagem de luz quando comparada ao dissilicato de lítio. Os materiais restauradores indiretos estudados apresentaram comportamentos distintos com relação à passagem de luz. O tipo de aparelho fotoativador influenciou a irradiância através dos diferentes materiais restauradores.

This study evaluated the influence of different types of restorative indirect materiais (zirconium oxide and lithium disilicate) in transmittance of light emitted by different types of curing units. Discs with 1 mm thickness and 10 mm dia meter were prepared from the indirect restorative materiais: IPS e.max ZirCAD (Ivoclar Vivadent) and IPS e.max (Ivoclar Vivadent). A nanofluorapatite ceramic (IPS e.max, Ivoclar Vivadent) was applied over theindirect materiais with 1 mm thickness. Five different light curing units were tested: Arc Light II (Air Technologies), ColtoLux LED (Colténe Whaledent), Elipar Free Light 2 (3M ESPE), Astralis 10 (Ivoclar Vivadent) and Ultralume 5 (Ultradent), which was used in regular mode, only light blue and only violet. The Irradiance through different restorative materiais was measured using a spectroradiometer (DAS 2100, Labsphere) associated with a specific software (Spectra Suite, Ocean Optics). Data were analyzed by two-way analysis of variance and Tukey test (p:s;O,05). The plasma are curing unit (Arc Light 11) showed the highest irradiance values through different restorative materiais, while the light source Ultralume 5, violet mode, showed the lowest irradiance values through different restorative materiais. The zirconia allowed higher light intensity passed through it when compared to lithium disilicate. The indirect restorative materiais tested showed distinct properties regarding the transmittance of light. Type of curing unit significantly influenced the Irradiance through different restorative materiais.

Fully automated algorithm for wound surface area assessment.

Worldwide, clinicians, dentists, nurses, researchers, and other health professionals need to monitor the wound healing progress and to quantify the rate of wound closure. The aim of this study is to demonstrate, step by step, a fully automated numerical method to estimate the size of the wound and the percentage damaged relative to the body surface area (BSA) in images, without the requirement for human intervention. We included the formula for BSA in rats in the algorithm. The methodology was validated in experimental wounds and human ulcers and was compared with the analysis of an experienced pathologist, with good agreement. Therefore, this algorithm is suitable for experimental wounds and burns and human ulcers, as they have a high contrast with adjacent normal skin.

Silorane- and high filled-based"low-shrinkage" resin composites: shrinkage, flexural strength and modulus

This study compared the volumetric shrinkage (VS), flexural strength (FS) and flexural modulus (FM) properties of the low-shrinkage resin composite Aelite LS (Bisco) to those of Filtek LS (3M ESPE) and two regular dimethacrylate-based resin composites, the microfilled Heliomolar (Ivoclar Vivadent) and the microhybrid Aelite Universal (Bisco). The composites (n = 5) were placed on the Teflon pedestal of a video-imaging device, and VS was recorded every minute for 5 min after 40 s of light exposure. For the FS and FM tests, resin discs (0.6 mm in thickness and 6.0 mm in diameter) were obtained (n = 12) and submitted to a piston-ring biaxial test in a universal testing machine. VS, FS, and FM data were submitted to two-way repeated measures and one-way ANOVA, respectively, followed by Tukey's post-hoc test (a = 5%). Filtek LS showed lower VS than did Aelite LS, which in turn showed lower shrinkage than did the other composites. Aelite Universal and Filtek LS exhibited higher FS than did Heliomolar and Aelite LS, both of which exhibited the highest FM. No significant difference in FM was noted between Filtek LS and Aelite Universal, while Heliomolar exhibited the lowest values. Aelite LS was not as effective as Filtek LS regarding shrinkage, although both low-shrinkage composites showed lower VS than did the other composites. Only Filtek LS exhibited FS and FM comparable to those of the regular microhybrid dimethacrylate-based resin composite.

Silorane- and high filled-based "low-shrinkage" resin composites: shrinkage, flexural strength and modulus.

This study compared the volumetric shrinkage (VS), flexural strength (FS) and flexural modulus (FM) properties of the low-shrinkage resin composite Aelite LS (Bisco) to those of Filtek LS (3M ESPE) and two regular dimethacrylate-based resin composites, the microfilled Heliomolar (Ivoclar Vivadent) and the microhybrid Aelite Universal (Bisco). The composites (n = 5) were placed on the Teflon pedestal of a video-imaging device, and VS was recorded every minute for 5 min after 40 s of light exposure. For the FS and FM tests, resin discs (0.6 mm in thickness and 6.0 mm in diameter) were obtained (n = 12) and submitted to a piston-ring biaxial test in a universal testing machine. VS, FS, and FM data were submitted to two-way repeated measures and one-way ANOVA, respectively, followed by Tukey's post-hoc test (a = 5%). Filtek LS showed lower VS than did Aelite LS, which in turn showed lower shrinkage than did the other composites. Aelite Universal and Filtek LS exhibited higher FS than did Heliomolar and Aelite LS, both of which exhibited the highest FM. No significant difference in FM was noted between Filtek LS and Aelite Universal, while Heliomolar exhibited the lowest values. Aelite LS was not as effective as Filtek LS regarding shrinkage, although both low-shrinkage composites showed lower VS than did the other composites. Only Filtek LS exhibited FS and FM comparable to those of the regular microhybrid dimethacrylate-based resin composite.

Effect of water storage on bond strength of self-adhesive resin cements to zirconium oxide ceramic.

PURPOSE: To evaluate the microshear bond strength of resin cements to yttrium-stabilized tetragonal zirconium oxide surfaces after water storage for 24 h or 1 year. MATERIALS AND METHODS: Four self-adhesive (BisCem, G-Cem, RelyX Unicem, SeT) and one conventional resin cement (RelyX ARC) were tested. The materials were mixed and inserted in tubes (0.75 mm diameter × 1 mm height) that were placed over the zirconium oxide surface. Specimens were tested after 24-h or 1-year water storage. Microshear testing was performed using a universal testing machine. Shear bond strength results were analyzed using two-way ANOVA and Tukey's test (5%). RESULTS: After 24-h water storage, no difference was found between G-Cem and RelyX Unicem resin cements; however, their bond strength means to zirconium oxide were statistically higher than RelyX ARC. The bond strength values of all resin cements dropped significantly after 1 year of water storage. G-Cem presented the highest values among cements after long-term water exposure. CONCLUSIONS: One-year water storage decreased the microshear bond strengths to zirconium oxide for all resin cements tested.

Analysis of the interfacial micromorphology and bond strength of adhesive systems to Er:YAG laser-irradiated dentin.

UNLABELLED: This study evaluated the effects of different parameters of dentin irradiation with erbium -doped yttrium aluminum garnet (Er:YAG) laser on bond strength to dentin and analyzed the ultramorphological characteristics of resin-laser-irradiated dentin interfaces using a transmission electron microscope (TEM). Dentin surfaces were abraded with SiC paper (600 grit) or Er:YAG laser-irradiated (120/4, 140/6, 180/4, or 200/6 mJ/Hz). Three adhesive systems were tested: Single Bond Plus (3M ESPE), Clearfil Protect Bond (Kuraray Med.), and Clearfil Tri-S Bond (Kuraray Med.). Treatments were performed over flat dentin surfaces of human third molars. Specimens were stored in distilled water for 1 week or 6 months and prepared for a microtensile bond strength test and interfacial ultrastructure for analysis. Microtensile bond strength data (n = 5) were analyzed with three-way analysis of variance. Irradiation with Er:YAG laser did not reduce the bond strength values for self-etching adhesives even after 6 months of water storage. The hybrid layer formation was observed only when the adhesives were applied to non-irradiated dentin (control group). Nanoleakage occurred in all resin-dentin interfaces using Single Bond Plus for both periods. Nanoleakage pattern and bond strength of self-etching adhesives to dentin were less affected by Er:YAG laser irradiation and by the 6-month storage in water than was those of the etch-and-rinse adhesive. TEM analysis revealed no hybridization when dentin was laser-irradiated. CLINICAL SIGNIFICANCE: Minimally invasive caries removal has been proposed. Nevertheless, bonding mechanisms to lased dentin are not entirely described. Knowing the interaction between the treated dentin and bonding agents and its behavior over time is of utmost importance for new technologies. Regarding that, two-bottle self-etching adhesive system provided a more consistent evidence of its better behavior when bonding to lased substrate.

Effect of adhesive system and application strategy on reduction of dentin permeability

This study evaluated the effect of adhesive systems and application strategies on dentin hydraulic conductance (HC). The buccal enamel was removed from bovine incisors to simulate laminate cavity preparations. After removing the roots and the coronal pulp, the buccal dentin was treated with EDTA solution (0.5 M) for 5 minutes, rinsed, ultrasonicated for 12 minutes and connected to a permeability device. HC of the specimens was measured at 10 psi (n = 5). Permeability was measured before and after bonding procedures using G-Bond (GB), Clearfil Tri-S Bond (CTS), Hybrid Coat (HY), Bond Force (BF), Adper Easy Bond (AEB) Silorane (SI), Clearfil SE Bond (CSE) and Adper Scotchbond Multi-Purpose (SMP) adhesives systems, which were applied following three strategies: 1) according to the manufacturers' instructions; 2) two coats of all-in-one self-etching adhesives (GB, CTS, HY, BF, AEB) or priming step plus two coats of bonding resin for the other systems (SI, CSE and SMP); and 3) a thin layer of a flowable composite applied over one coat of all-in-one self-etching adhesives or primed surface for SI, CSE and SMP adhesives. No significant difference was observed among the application modes concerning their ability to reduce HC. None of the adhesives showed complete sealing (100%) of the bovine tooth dentin. SI exhibited lower HC than SMP, however, they were not significantly different from the other systems. The results suggest that all systems tested result in an HC reduction of more than 90%. The wet bonding technique seemed to be more sensitive for dentin sealing.

Effect of adhesive system and application strategy on reduction of dentin permeability.

This study evaluated the effect of adhesive systems and application strategies on dentin hydraulic conductance (HC). The buccal enamel was removed from bovine incisors to simulate laminate cavity preparations. After removing the roots and the coronal pulp, the buccal dentin was treated with EDTA solution (0.5 M) for 5 minutes, rinsed, ultrasonicated for 12 minutes and connected to a permeability device. HC of the specimens was measured at 10 psi (n = 5). Permeability was measured before and after bonding procedures using G-Bond (GB), Clearfil Tri-S Bond (CTS), Hybrid Coat (HY), Bond Force (BF), Adper Easy Bond (AEB) Silorane (SI), Clearfil SE Bond (CSE) and Adper Scotchbond Multi-Purpose (SMP) adhesives systems, which were applied following three strategies: 1) according to the manufacturers' instructions; 2) two coats of all-in-one self-etching adhesives (GB, CTS, HY, BF, AEB) or priming step plus two coats of bonding resin for the other systems (SI, CSE and SMP); and 3) a thin layer of a flowable composite applied over one coat of all-in-one self-etching adhesives or primed surface for SI, CSE and SMP adhesives. No significant difference was observed among the application modes concerning their ability to reduce HC. None of the adhesives showed complete sealing (100%) of the bovine tooth dentin. SI exhibited lower HC than SMP, however, they were not significantly different from the other systems. The results suggest that all systems tested result in an HC reduction of more than 90%. The wet bonding technique seemed to be more sensitive for dentin sealing.

Adhesive bonding of resin cements to cast titanium with adhesive primers.

The purpose of this study was to evaluate the effects of adhesive primer applications on the bond strength of resin cements to cast titanium. Four adhesive primers - Metaltite, Metal Primer II, Alloy Primer and Ceramic Primer - and their respective resin cements - Bistite II DC, Link Max, Panavia F 2.0, RelyX Unicem and RelyX ARC - were tested. Cast plates were prepared from titanium ingots (n=6 specimens/cement) and had their surfaces airborne-particle abraded with Al2O3 (50 µ m). Three resin cement cylinders were built on each bonded titanium surface, using a cylindrical translucent tubing mold and were subjected to micro-shear testing. Data were analyzed statistically by two-way ANOVA and Tukey's post-hoc test (α=0.05). The application of Metal Primer II and Ceramic Primer resulted in significant higher bond strength for Link Max and RelyX Unicem resin cements, respectively, than nonuse of adhesive primers. Panavia F 2.0 and RelyX ARC yielded high bond strength means with or without adhesive primers. The use of adhesive primers might increase the bond strength to cast titanium depending on the resin cement used.

Influence of viscosity and polymerization mode on bond strength of dual-curing resin luting agent to dentin

Aim: To evaluate the influence of the viscosity and curing mode on the bond strength of two resincements to dentin. Methods: Eight experimental groups were formed (n = 7) according to thedual-cure resin cements (Nexus 2 - Kerr Corp. and Variolink II - Ivoclar Vivadent), curing modes(dual-cure or self-cure) and viscosities (low and high). Resin cements were applied to pre-curedcomposite resin discs (2 mm thick, Sinfony -3M ESPE), which were fixed to bonded dentinsurfaces. The restored teeth were either light-activated (XL3000 - 3M ESPE) or allowed to selfcuring only. After 24 h, the teeth were both mesiodistally and buccolingually sectioned to obtainbonded beam specimens (0.8 mm2 cross-sectional area). Each specimen was tested in microtensilestrength at a crosshead speed of 0.5 mm/min until failure. Results: Data (in MPa) were analyzedstatistically by three-way ANOVA and Tukey’s post-hoc test (pre-set á = 0.05). No significantdifference was observed between resin cements (p=0.26) and viscosities (p=0.13), however, thecuring mode affected the BS within the viscosities (p=0.01). Statistically significant difference wasobserved for low viscosity: Nexus 2: 23.8(10.6) (dual-cure) and 16.0(5.1) (self-cure); VariolinkII: 28.7(8.7) (dual-cure) and 11.9(3.0) (self-cure). Conclusions: Light activation yielded higherbond strength for the low-viscosity versions of the resin cements.

Adhesive bonding of resin cements to cast titanium with adhesive primers

The purpose of this study was to evaluate the effects of adhesive primer applications on the bond strength of resin cements to cast titanium. Four adhesive primers - Metaltite, Metal Primer II, Alloy Primer and Ceramic Primer - and their respective resin cements - Bistite II DC, Link Max, Panavia F 2.0, RelyX Unicem and RelyX ARC - were tested. Cast plates were prepared from titanium ingots (n=6 specimens/cement) and had their surfaces airborne-particle abraded with Al2O3 (50 μ m). Three resin cement cylinders were built on each bonded titanium surface, using a cylindrical translucent tubing mold and were subjected to micro-shear testing. Data were analyzed statistically by two-way ANOVA and Tukey's post-hoc test (α=0.05). The application of Metal Primer II and Ceramic Primer resulted in significant higher bond strength for Link Max and RelyX Unicem resin cements, respectively, than nonuse of adhesive primers. Panavia F 2.0 and RelyX ARC yielded high bond strength means with or without adhesive primers. The use of adhesive primers might increase the bond strength to cast titanium depending on the resin cement used.

O objetivo deste estudo foi avaliar o efeito da aplicação de primers na resistência de união de cimentos resinosos ao titânio. Quatro primers - Metaltite, Metal Primer II, Alloy Primer and Ceramic Primer - e seus respectivos cimentos resinosos - Bistite II DC, Link Max, Panavia F 2.0, RelyX Unicem and RelyX ARC - foram testados. Placas de titânio foram preparadas a partir da fundição de lingotes (n=6 espécimes/cimento) e as superfícies dessas placas foram jateadas com partículas de Al2O3 (50 μ m). Três cilindros de cimento resinoso foram construídos em cada placa de titânio, utilizando moldes transparentes com formato de cilindro e foram submetidos ao teste de microcisalhamento. Os dados foram analisados pela ANOVA (dois fatores) e teste de Tukey (α=0,05). A aplicação do Metal Primer II e do Ceramic Primer resultou no aumento significativo da resistência de união para os cimentos resinosos Link Max e RelyX Unicem, respectivamente. Os cimentos Panavia F 2.0 e o RelyX ARC mostraram altos valores de resistência de união com ou sem o uso dos primers. A aplicação dos primers pode aumentar a resistência de união dos cimentos resinosos ao titânio, dependendo do tipo de cimento resinoso utilizado.

Efeito da aplicação de primers para metal na resistência de união de cimentos resinosos à zircônia / Effect of application of metal primers on the bond strength of resin cements to zirconia

O objetivo deste estudo foi avaliar o efeito da aplicação de primers para estruturas à base de ligas metálicas na resistência de união (RU) de um cimento convencional e de um cimento autoadesivo à zircônia, utilizando o teste de microcisalhamento. Foram preparadas 60 placas de óxido de zircônia (Cercon), com dimensões de 13 x 5 x 1 mm (comprimento x largura x espessura). Essas placas foram jateadas com óxido de alumínio e divididas em seis grupos experimentais, segundo o tratamento utilizado (n = 10). Os primers e cimentos foram aplicados de acordo com as recomendações dos fabricantes e grupos experimentais. Após o tratamento da zircônia, cilindros de cimento resinoso foram construídos na superfície das placas, utilizando matrizes (Tygon) com 0,7 x 1 mm (diâmetro x altura). As amostras foram armazenadas em água destilada por 24 h à 37ºC e submetidas ao ensaio de microcisalhamento (0,5 mm/min, Instron 4411). Os valores obtidos foram analisados pela ANOVA (2 fatores) e teste Tukey (α = 0.05). Somente a utilização do Metal Primer II aumentou a RU dos dois cimentos resinosos à zircônia. O cimento autoadesivo RelyX U-100 obteve as maiores médias de RU quando comparado ao cimento convencional Bistite II DC, para todos os tratamentos de superfície utilizados. Para se obter maior RU à zircônia Cercon deve ser utilizado o Metal Primer II e o cimento autoadesivo RelyX U-100.

The aim of this study was to evaluate the effect of alloy primers on the bond strength (BS) of conventional resin cement and self-adhesive cement to zirconia using the microshear bond strength test. Sixty ceramic plates, with dimensions of 13 x 5 x 1 mm (length x width x thickness), were prepared . The ceramic plates were air-abraded with aluminum oxide and divided into six experimental groups, according to the treatment used (n = 10). The primers and resin cements were applied according to manufacturers' recommendations and experimental groups. After treatment of the zirconia, resin cement cylinders were constructed on their surfaces by using matrix (Tygon) with 0.7 x 1 mm (diameter x height). The samples were stored in distilled water for 24 hours at 37°C and tested in a universal testing machine (0.5 mm/min, Instron 4411). The data were analyzed by ANOVA (two factors) and Tukey test (α = 0.05). Only the use of Metal Primer II increased the bond strength of all resin cements to zirconia. The self-adhesive RelyX U-100 cement promoted higher bond strength values than Bistite II DC, for all surface treatments. To obtain the highest bond strength to zirconia, it must be used the Metal Primer II and the self-adhesive RelyX U-100 resin cement.