Remineralizing pretreatment using casein phosphopeptide-amorphous calcium phosphate fluoride, self-assembling peptide, and nanohydroxyapatite gel activation via invisible infrared light on the dentin microhardness and micro shear bond strength to the composite restoration.

AIM: Different remineralizing pretreatments Casein phosphopeptide-amorphous calcium phosphate fluoride (CPP-ACPF), tricalcium phosphate fluoride (TCP-F), self-assembling peptide (SAP) P11-4 and 10 % Nanohydroxyapatite (nHA) gel activation via invisible infrared light on the dentin microhardness (MH) and micro shear bond strength (µSBS) of composite restoration. METHODS: Seventy-five human molar teeth were collected and the dentinal surface of all the samples was exposed to different demineralizing solutions. (n = 15) Group 1 (demineralized dentin), Group 2 (CPP ACP), Group 3 (TCP-F), Group 4 (SAP P11-4), Group 5 (nHA gel activation via invisible infrared light). MH assessment was performed using Vickers hardness. Each group of 10 samples was subjected to composite restoration buildup and µSBS were tested. The debonded samples were then observed under a stereo-microscope for failure analysis. ANOVA was conducted, along with Tukey's post hoc analysis, to examine the µSBS of composite and MH of the remineralized surface. RESULTS: nHA gel activation via invisible infrared light pretreated specimens showed the maximum outcomes of surface hardness (331.2 ± 77.3) and bond strength (10.38 ± 2.77). However, Group 4 (SAP P11-4) (148.3 ± 29.2) remineralized dentin displayed minimum scores of MH and µSBS (5.88 ± 1.01). CONCLUSION: Remineralizing pretreatment nHA gel activation via invisible infrared light and casein phosphopeptide-amorphous calcium phosphate fluoride seem to improve the dentin MH and µSBS of the composite restoration.

Comparison of the translucency parameters and bond strength of 5Y-ZP zirconia, 3-YTZP zirconia, and lithium disilicate.

Background: E-max is a more aesthetic material than traditional zirconia. In addition, the bond strength of traditional zirconia with adhesive cements is lower. There are not enough studies on how the aesthetic values and bond strength of 5-YZP, the new generation zirconia, compare to e-max and traditional zirconia. Can 5-YZP be an alternative to e-max in terms of aesthetics and bond strength? Aim: The aim of the study is to compare the translucency property and bonding ability of 5y-zp zirconias with previous generation zirconias and lithium disilicate. Materials and Methods: Two types of zirconia Katana UT and Katana HT for measuring translucency values; and using a type of lithium disilicate IPS e.max CAD LT, three groups were formed (n = 10). Translucency specimens were fabricated (n = 10). Their L*a*b* values were measured against a black-and-white background with a spectrophotometer, and DE00 was calculated. To perform micro-shear tests, a cylinder design was made from zirconia and IPS e.max CAD blocks (n = 20). After the samples were aged by thermal cycle, the micro-shear test was applied to specimens cemented to teeth extracted with two different adhesive cement systems. Results: According to the results of one-way analysis of variance, a statistically significant difference was found between the translucency parameter (TP) values of the groups. According to Tukey's honestly significant difference (HSD) multiple comparisons, the values of the three groups are statistically different from each other. Although IPS e.max CAD group has the highest TP values, the Katana HT group has the lowest values. Conclusion: 5Y-PZ has a TP intermediate to those of 3Y-TZP and lithium disilicate. Long-term bond strength of 3Y-TZP and 5Y-ZP were similar to those of lithium disilicate. To be an alternative to glass ceramics in the anterior region, translucency and bond strength values need to be improved.

Argon Plasma Treatment Effects on the Micro-Shear Bond Strength of Lithium Disilicate with Dental Resin Cements.

The low bond strength of lithium disilicate (LD) ceramics to dental resin cements remains a critical issue for dental applications because it leads to frequent replacement and causes tooth tissue destruction and consumption. The objective of this study was to examine the effects of atmospheric non-thermal argon plasma (NTP) treatment on LD to improve its micro-shear bond strength (µSBS) with dental resin cements because LD mostly experiences shear stress for its commonly used dental applications as crowns or veneers. Argon plasma treatment was performed on hydrofluoric (HF) acid-etched LD surfaces, and then commercial resin cements were subsequently applied to the treated LD surfaces. The plasma treatment significantly reduced the water contact angle of the LD surface to less than 10° without changing the surface morphology. The µSBS test was performed with cement-bonded LD samples after 24 h and 30 days, as well as after 1000 cycles of thermal cycling. The test results show that, as compared with the untreated controls, 300 s of plasma treatment significantly improved the LD-resin cement bond strength by 59.1%. After 30 days of storage in DI water and 1000 cycles of thermal cycling, the plasma-treated LD samples show 84.2% and 44.8% higher bond strengths as compared to the control samples, respectively. The plasma treatment effect on LD surfaces diminished rapidly as the bond strength decreased to 25.5 MPa after aging in the air for 1 day prior to primer and cement application, suggesting that primers should be applied to the LD surfaces immediately after the plasma treatment. These results demonstrate that, when applied with caution, plasma treatment can activate LD surfaces and significantly improve the SBS of LD with dental resin cements in both short-term and long-term periods.

Effect of plasma surface treatment of three different CAD/CAM materials on the micro shear bond strength with resin cement (A comparative in vitro study).

Objectives: This study aimed to evaluate and compare the effect of plasma treatment versus conventional treatment on the micro shear bond strength (µSBS), surface roughness, and wettability of three different CAD/CAM materials. Materials and methods: Sixty cylindrical specimens (5 mm diameter × 3 mm height) were prepared from three different CAD/CAM materials: Group A: Zirconia, Group B: Lithium disilicate, and Group C: Resin nano-ceramic. Each group was subdivided into two subgroups according to surface treatment used: Subgroup I: Conventional treatment, zirconia was sandblasted with Al2O3, while lithium disilicate and resin nano-ceramic were etched with hydrofluoric acid. Subgroup II: Plasma treatment, the surface of each material was treated with a plasma device (PiezoBrush® PZ3 Handheld Device, Relyon Plasma, Regensburg, Germany). G-Multi PRIMER was applied, then self-adhesive cement (G-CEM ONE) was applied using a split mold (1 mm diameter × 3 mm height), and µSBS was tested in a universal testing machine. The surface roughness was measured using a profilometer. Nine additional specimens of each material for wettability test using an optical tensiometer. Statistical analysis: The data were analyzed using ANOVA and Bonferroni test at a level of significance of 0.05. Results: The highest mean of µSBS was recorded by AII (27.3 MPa), while the lowest was recorded by AI (17.9 MPa). One-way ANOVA test revealed a significant difference among groups. Bonferroni test showed each two subgroups significant difference except subgroups AI, CI and BII, CII, where there was a non-significant difference. For all CAD/CAM materials, conventional treatment increased the surface roughness compared to plasma treatment, while the contact angle decreased after plasma treatment. Conclusion: Plasma treatment increased the µSBS of resin cement to zirconia significantly while not significantly affecting the µSBS of resin nano-ceramic. Conventional treatment of lithium disilicate provided significantly higher µSBS than plasma treatment.

Effect of Different Etching Times on Pit-and-Fissure Sealant Micro-Shear Bond Strength to the Enamel of Primary Teeth.

Successful clinical use of pit-and-fissure sealants relies on the sufficient etching of the enamel, field isolation and sealant retention. The etching time changes the physical and mechanical surface properties of the etched tooth tissues; therefore, it impacts both etching depth and the bond strength of sealants to the enamel. We examined if reducing the recommended 15 s etching time of primary teeth enamel affects the micro-shear bond strength (µSBS) of pit-and-fissure sealants. The cusps of forty non-carious, extracted human primary molars were separately etched for 8, 15 or 30 s. Then, a pit-and-fissure sealant was placed and light-cured. The µSBS values were evaluated and compared among the three groups. The mean µSBS values ± standard deviations were 34.68 ± 16.93, 34.19 ± 17.35 and 36.56 ± 16.57 MPa in the cusps etched for 8, 15 and 30 s, respectively. No statistically significant differences in µSBS were observed among the three test groups. In this study, we showed for the first time that the recommended etching time of primary teeth enamel may be reduced from 15 to 8 s without compromising the µSBS of the sealant. Further evaluations in a clinical setting are warranted.

Effect of Different Etching Times with Hydrofluoric Acid on the Bond Strength of CAD/CAM Ceramic Material.

The objective of this study was to evaluate the influence of hydrofluoric acid (HF) and conditioning time on the micro-shear bond strength (µSBS) between dual-cure resin cement and glass-ceramic materials, such as lithium disilicate ceramic (IPS e.max CAD, Ivoclar Vivadent) (EX) and leucite-reinforced ceramic (IPS Empress CAD, Ivoclar Vivadent) (EP), and also a hybrid ceramic (Vita Enamic, Vita Zahnfabrik) (VE). Eighteen sections with 1 mm thickness were cut from each CAD/CAM material and randomly divided into three groups, according to the surface etching time (30 s, 60 s, 90 s). The surface treatment was performed using 9.5% HF acid gel, then resin cement was applied on the prepared ceramic plates and light cured. µSBS values between resin cement and the ceramic material were measured with a universal testing machine at a crosshead speed of 0.5 mm/min until the failure occurred. The fractured surfaces of specimens were microscopically evaluated, and failure modes were classified as: adhesive between resin cement and ceramic, cohesive within ceramic or cement and mixed failure. Surface roughness of etched samples was examined using a scanning electron microscope. Obtained data were statistically analysed using one-way analysis of variance (ANOVA) and Bonferroni post hoc test with a level of significance α = 0.05. The results of the statistical methods applied indicate that µSBS mean difference for leucite-reinforced ceramic (EP) was statistically significant (p < 0.05). However, µSBS values for hybrid ceramic (VE) and lithium disilicate ceramic (EX) were not affected, from a statistical point of view, by the conditioning time (p > 0.05).

Influence of irradiation distance on the mechanical performances of resin composites polymerized with high-irradiance light curing units.

BACKGROUND: The aim of this study was to evaluate the influence of increased irradiation distance on the flexural strength (FS), dentin micro-shear bond strength (µSBS), and the degree of conversion (DC) of bulk-fill flowable, conventional flowable, and packable resin composites. METHODS: The resin composites tested were Surefil® SDR™ (SDR), Filtek Z350 XT Flowable Restorative A2 shade (Z3F), and Filtek Z350 XT Universal Restorative A2 shade (Z3P). Specimens were cured at four irradiation distances (0, 2, 4, and 8 mm) with an Elipar DeepCure-S LED curing light for 20 s. FS tests were performed (n = 15) using bar-shaped specimens (8 mm × 2 mm × 2 mm) of the resin composites. µSBS tests were performed on the occlusal surfaces of extracted third molars from humans that were ground to expose dentin (n = 15). DC was measured by using Raman spectroscopy on the top and bottom surfaces of disk specimens (2-mm thick) (n = 3). To further investigate whether extended irradiation times could compensate for reduced irradiance, additional Z3P specimens were prepared, which were light-cured at 8-mm distances for 40 and 60 s and subjected to FS tests, µSBS tests, and Raman spectroscopy. Both two-way and one-way ANOVA were used for statistical analyses. RESULTS: Both FS and DC of Z3P specimens cured at an 8-mm distance were significantly lower than those cured at shorter distances (p < 0.05), whereas the FS and DC of the Z3F and SDR specimens were not significantly influenced by increasing distances. The µSBSs of the three types of resin composites reduced with increasing irradiation distances. The FS, µSBS, and DC of the Z3P specimen light-cured at 8 mm for 40 s were comparable to those of the Z3P specimen cured at 0 mm for 20 s. CONCLUSIONS: Increasing the irradiation distance to 8 mm can have a deleterious influence on mechanical performances, including the FS, DC, and dentin µSBS, of the resin composites polymerized with high-irradiance light curing units.

Micro-shear bond strength of different surface treatments on a polymer infiltrated ceramic network.

Background: Polymer infiltrated ceramic networks, or hybrid ceramics, are a combination of infiltrating polymerizable organic monomers into a pre-sintered porous ceramic matrix. In addition to having good mechanical properties, the polymer infiltrated ceramic network must comply with the possibility of adequate bonding to the resinous cement. The surface conditioning of this hybrid material must be carefully considered due to its organic composition and ceramic network. The purpose of this research is to evaluate the effect of hydrofluoric acid and a self-etching ceramic primer, under two different application times, on the bond strength of a polymer infiltrated ceramic network. Methods: Blocks of a polymer infiltrated ceramic network were cut to obtain sheets, and these were randomized into five groups. For the group termed AAS, airborne-particle abrasion with Al 2O 3 (aluminum oxide) of 50µm was used. For groups HF2 and HF6, hydrofluoric acid was used for 20 and 60 seconds respectively, and for the groups MB2 and MB6, a self-etch ceramic primer was applied for 20 and 60 seconds respectively. A silane was applied to the groups AAS, HF2, and HF6 after the treatment. After 24-hour storage in distilled water, a micro-shear bond strength test was performed using a universal mechanical testing machine. All samples were evaluated in a stereomicroscope at 40x and 50x to determine the type of failure. Results: The highest and lowest values of bond strength were reported by groups MB6 and AAS, respectively. Groups HF2, HF6, MB6, and MB2 did not report statistically significant differences. The predominant failure pattern was a mixed failure. Conclusions: With the limitations of the present investigation, the treatments of self-etching ceramic primer and hydrofluoric acid followed by silane were reported to be statistically equal at 20 and 60 seconds.

Evaluation of enamel roughness after the removal of brackets bonded with different materials: In vivo study

Abstract The aims of this in vivo study were to evaluate the effect of bonding with resin-modified glass ionomer cement (RMGIC) and to assess enamel surface roughness before and after the removal of brackets bonded with composite or RMGIC from the maxillary central incisors. Fifteen orthodontic patients were selected for the study. For each patient, the teeth were rinsed and dried, and brackets were bonded with composite (Transbond XT) and RMGIC (Vitremer Core Buildup/Restorative). At the conclusion of orthodontic treatment, their brackets were removed. Dental replicas were made of epoxy resin in initial conditions (before bonded) and after polishing with an aluminum oxide disc system. Adhesive remnant index (ARI) and surface roughness was measured on the dental replicas and data were evaluated statistically by Mann-Whitney and paired t-test, respectively. No bracket debonding occurred during patients' treatment periods. It was verified that the ARI values of the two maxillary central incisors were similar (p = 0.665). For both bonding materials, the ARI value of 3 was predominant. After polishing, surface roughness was similar in the composite and RMGIC groups (0.245 μm and 0.248 μm, respectively; p = 0.07). In both groups, enamel surface roughness values were significantly lower after polishing compared with the initial condition (p < 0.001). RMGIC promoted efficiency in cementing brackets without fail during treatment; the choice of composite or RMGIC materials was not a factor that influenced the roughness of the enamel surface, however, polishing led to smoother surfaces than those found at the beginning of the treatment.

Resumo Os objetivos deste estudo in vivo foram avaliar o efeito da colagem com cimento de ionômero de vidro modificado por resina (CIVMR) e a rugosidade da superfície do esmalte antes e após a remoção dos braquetes colados com compósito ou CIVMR em incisivos centrais superiores. Quinze pacientes ortodônticos foram selecionados para o estudo. Para cada paciente, os dentes foram lavados e secos, e os braquetes colados com compósito (Transbond XT) e CIVMR (Vitremer Core Buildup / Restorative). Ao término do tratamento ortodôntico, os braquetes foram removidos. As réplicas dentais foram confeccionadas em resina epóxica nas condições iniciais (antes da colagem) e após o polimento com sistema de discos de óxido de alumínio. O índice de remanescente adesivo (IRA) e a rugosidade da superfície foram mensurados nas réplicas dentais e os dados foram avaliados estatisticamente por Mann-Whitney e teste t pareado, respectivamente. Não ocorreu descolagem de braquetes durante os períodos de tratamento dos pacientes. Verificou-se que os valores do IRA dos dois incisivos centrais superiores foram semelhantes (p = 0,665). Para ambos os materiais de colagem, o valor de IRA predominante foi 3. Após o polimento, a rugosidade da superfície do esmalte foi semelhante nos grupos compósito (0,245 μm) e CIVMR (0,248 μm) (p = 0,07). Em ambos os grupos, os valores de rugosidade da superfície do esmalte foram significativamente menores após o polimento em comparação com a condição inicial (p <0,001). CIVMR promoveu eficiência na colagem de braquetes sem falhas durante o tratamento; a escolha dos materiais compósito ou CIVMR não foi um fator que influenciou na rugosidade da superfície do esmalte, porém, o polimento levou a superfícies mais lisas do que as encontradas no início do tratamento.

Bonding performance of self-etch adhesives to enamel bleached with different peroxide concentrations

Abstract The aim of this study was to evaluate the micro-shear bond strength (µSBS) of one and two steps self-etch adhesive systems after enamel bleaching with photo-activated bleaching systems of different hydrogen peroxide (HP) concentration. Occlusal enamel of forty intact human molars were flattened and assigned into four groups. GI Unbleached, GII, GIII, and GIV were bleached with Pyrenees (3.5% HP), GC TiON (20% HP), and Hi-Lite (35% HP) respectively. Enamel treatment with one and two steps self-etch adhesives (Clearfil S3 Bond- S3, and Clearfil SE Bond-SE) then micro-tubes were fixed on enamel and filled with AP-X composite (n=5). Bond was tested with the universal testing machine. Data were analyzed using two-way ANOVA and Tukey's tests at 5 % level of significance. The µSBS was significantly different between adhesives (F=154.46; p<0.05) and bleaching systems (F=77.33; p<0.05) with significant interaction. Specimens bonded with S3 shows a significantly lower μSBS than those bonded with SE (p<0.05) in all groups. For both adhesives the bleached groups demonstrate lower µSBS than unbleached except specimens bleached with Pyrenees and bonded with SE (p>0.05). A significant difference was observed between groups of the bleaching systems (p<0.05). Different peroxide concentrations photo-activated bleaching systems adversely affect μSBS of one and two steps self-etch adhesives. Low concentration system (Pyrenees) does not influence the bond strength of two steps adhesive.

Resumo O objetivo deste estudo foi avaliar a resistência ao cisalhamento (µSBS) de sistemas auto-adesivos de um e dois passos após clareamento do esmalte com sistemas de clareamento foto-ativados de diferentes concentrações de peróxido de hidrogênio (HP). O esmalte oclusal de quarenta molares humanos intactos foi aplainado e atribuído em quatro grupos. GI Unbleached, GII, GIII, e GIV foram branqueados com Pyrenees (3,5% HP), GC TiON (20% HP), e Hi-Lite (35% HP) respectivamente. Tratamento de esmalte com adesivos de um e dois passos auto-adesivos (Clearfil S3 Bond- S3, e Clearfil SE Bond-SE), depois os microtubos foram fixados no esmalte e preenchidos com composto AP-X (n=5). A resistência ao cisalhamento foi testada com a máquina universal de testes. Os dados foram analisados usando os testes de ANOVA e Tukey de duas vias a um nível de 5% de significância. O µSBS foi significativamente diferente entre adesivos (F=154,46; p<0,05) e sistemas de clareadores (F=77,33; p<0,05) com interação significativa. Os espécimes colados com S3 mostram um μSBS significativamente inferior aos colados com SE (p<0,05) em todos os grupos. Para ambos os adesivos, os grupos clareados demonstram µSBS inferiores aos não clareados exceto os espécimes clareados com Pyrenees e colados com SE (p>0,05). Foi observada uma diferença significativa entre os grupos dos sistemas de clareamento (p<0,05). Diferentes concentrações de peróxidos foto-ativados nos sistemas de clareamento afetam negativamente μSBS dos adesivos de uma e duas etapas de auto-colagem. O sistema de baixa concentração (Pyrenees) não influenciou a resistência ao cisalhamento do adesivo de duas etapas.

Micro-shear bond strengths of resin-matrix ceramics subjected to different surface conditioning strategies with or without coupling agent application.

PURPOSE: This study aimed to assess the influence of various micromechanical surface conditioning (MSC) strategies with or without coupling agent (silane) application on the micro-shear bond strength (µSBS) of resin- matrix ceramics (RMCs). MATERIALS AND METHODS: GC Cerasmart (GC), Lava Ultimate (LU), Vita Enamic (VE), Voco Grandio (VG), and Brilliant Crios (BC) were cut into 1.0-mm-thick slices (n = 32 per RMC) and separated into four groups according to the MSC strategy applied: control-no conditioning (C), air-borne particle abrasion with aluminum oxide particles (APA), 2W- and 3W-Er,Cr:YSGG group coding is missing. The specimens in each group were further separated into silane-applied and silane-free subgroups. Each specimen received two resin cement microtubules (n = 8 per subgroup). A shear force was applied to the adhesive interface through a universal test machine and µSBS values were measured. Data were statistically analyzed by using 3-way ANOVA and Tukey HSD test. Failure patterns were scrutinized under stereomicroscope. RESULTS: RMC material type, MSC strategy, and silanization influenced the µSBS values (P<.05). In comparison to the control group, µSBS values increased after all other MSC strategies (P<.05) while the differences among these strategies were insignificant (P>.05). For control and APA, there were insignificant differences between RMCs (P>.05). The silanization decreased µSBS values of RMCs except for VE. Considerable declines were observed in GC and BC (P<.05). CONCLUSION: MSC strategies can enhance bond strength values at the RMC - cement interface. However, the choice of MSC strategy is dependent on RMC material type and each RMC can require a dedicated way of conditioning.

The effect of different ceramic surface treatments on the repair bond strength of resin composite to lithium disilicate ceramic.

This study aimed to evaluate the bonding abilities and long-term durability of different repair agents when applied to lithium disilicate ceramics (LDS). Blocks of IPS e.max CAD were prepared and divided into four groups according to the surface treatment: Monobond Etch & Prime (ME), K-etchant GEL+Clearfil Universal Bond (UB), Bondmer Lightless (BL), and K-etchant GEL+G-Multi Primer (GMP). All treated ceramic specimens were bonded to resin composite and light-cured. The micro-shear bond strength was measured after 24 h of water storage or 5,000 thermocycles. ME and BL showed significantly higher initial bond strengths than UB and GMP (p<0.05). After 5,000 thermocycles, there was no significant difference in ME (p>0.05), but BL and GMP showed considerable reduction in bond strength (p<0.05); moreover, the samples of UB were all de-bonded before testing. ME and BL proved to be effective surface treatment materials for LDS.

Optical changes of human dentin after non-vital bleaching and effect of Er,Cr:YSGG laser on micro-shear bond strength of a self-etch and an etch-and-rinse adhesive system.

The aim was to evaluate the optical changes of bleached human dentin and the efficacy of Er,Cr:YSGG laser on micro-shear bond strength (µSBS) of two adhesive systems for immediate and delayed applications. Seventy-two human dentin specimens (1 mm) were obtained. Colour measurements of 30 specimens (control and bleaching groups) were made at baseline, after bleaching and a 7-day delay. Differences at colour (ΔE00), translucency (ΔTP00) and whiteness (ΔWID) were calculated by recorded data. Forty-two specimens were used to compare µSBS of a self-etch (Clearfil SE Bond [SE]) and an etch-and-rinse (Prime&Bond NT [PBNT]) adhesive to bleached dentin. Additional to a negative group, six groups were contemplated for each adhesive, considering the time of composite application (immediate, delayed) and whether additional surface treatment by laser (1 W, 2 W) or not. Colour and µSBS data were statistically analysed. For optical analysis, only ΔE00 and ΔWID calculated for the difference between baseline and bleaching were found significantly different for control and bleaching groups. Whiteness of bleached specimens was remarkably decreased after a 7-day delay. Despite immediate applications of SE showing lower µSBS than negative control, delayed applications showed no significant differences except that of the 2 W laser etching. For PBNT, laser etching increased µSBS for both of the immediate and delayed applications, and no significant difference was observed from negative control. Related with the preferred adhesive system, Er,Cr:YSGG laser etching can be an alternative for optimal bond strength of immediate restorations, but the clinicians should always keep in mind that perceived colour and whiteness will change by the passing time which can affect the shade match.

Effect of Etching Procedures on the Adhesion of Biofilm-Coated Dentin.

Oral biofilms coat all surfaces in the oral cavity including the exposed dentin surface. This study aimed to investigate biofilm removal by acid etching procedures and the effects of the residual biofilm on dentin surfaces on composite-dentin adhesion. Dentin discs were assigned to five groups: no biofilm formation (C); biofilm formation and no surface treatment (BF); biofilm formation and acid etching (BF-E); biofilm formation and acid etching followed by chlorhexidine soaking (BF-EC); and biofilm formation and rubbing with pumice, followed by acid etching (BF-RE). Biofilms were formed on saliva-precoated dentin discs by soaking the discs in Streptococcus mutans (S. mutans) suspension. Biofilm removal from the dentin surface was evaluated quantitatively and qualitatively by confocal laser scanning microscopy and scanning electron microscopy, respectively. To compare the bond strength of the biofilm-coated dentin discs with the surface treatments, specimens were assigned to four groups: no biofilm formation and acid etching (C-E); BF-E; BF-EC; and BF-RE. Assessments of the micro-shear bond strength and subsequent failure modes were performed. BF-E and BF-EC did not remove the biofilm, whereas BF-RE partially removed the biofilm attached to the dentin (p < 0.05). The bond strength of BF-RE was significantly higher than those of BF-E and BF-EC, but lower than that of C-E (p < 0.05). In conclusion, mechanical biofilm removal is recommended before etching procedures to enhance adhesion to the biofilm-coated dentin.

Effect of smear layer deproteinization with HOCl solution on the dentin bonding of conventional and resin-modified glass-ionomer cements.

The effect of smear layer-deproteinizing pretreatment using hypochlorous acid (HOCl) on the micro-shear bond strengths (µSBS) of conventional and resin-modified glass-ionomer cements (GIC) to dentin was investigated and compared with demineralizing pretreatment with polyacrylic acid (PAA). Three GICs: Fuji IX GP Extra (restorative conventional GIC), GC Fuji II LC EM (restorative resin-modified GIC), and GC Fuji Luting EX (luting resin-modified GIC), were used. One hundred fifty human molars were divided into groups (n = 10) according to the cements and dentin pretreatments; no pretreatment (control), 10 s PAA pretreatment, and HOCl pretreatment for 5, 15, or 30 s. After 24 h, µSBS was tested and the data were statistically analyzed using a two-way ANOVA, followed by Tukey's post-hoc test. HOCl pretreatment significantly increased µSBS of conventional GIC compared to the control group. For resin-modified restorative GIC, 5 s HOCl deproteinization significantly increased µSBS, while longer application times did not. There was no significant difference between HOCl-pretreated and control groups of resin-modified luting GIC. PAA pretreatment increased the µSBS of all cements significantly. In conclusion, smear layer deproteinization with HOCl can enhance the dentin bonding of conventional GIC. However, the residual radicals may adversely affect the polymerization of resin-modified GICs.

Micro-shear bond strength of bioactive cement to translucent zirconia after thermocycyling: a comparative in-vitro study / Resistência de união ao microcisalhamento do cimento bioativo à zircônia translúcida após termociclagem: estudo comparativo in vitro

Objective: the purpose of the study was to evaluate the micro-shear bond strength of different cements to translucent zirconia before and after thermocycling aging. Material and methods: Twelve translucent zirconia ceramic discs were used in the study. Specimens were sandblasted using 50 µm aluminum oxide (Al2 O3 ) particles. The specimens were divided into three groups (n = 4) according to the cement type: Panavia resin cement (control group), resin modified glass ionomer (RMGI), and Activa bioactive cement. Each group was further sub-divided into two equal subgroups (n = 2) according to whether the specimens were subjected to thermocycling or not. Thermocycling was performed in distilled water at 5000 cycles between 5 o C - 55 o C. The micro-shear bond strength test (µSBS) was measured using universal testing machine. Kruskal-Wallis test was used to compare between the three cements. Dunn's test was used for pair-wise comparisons when Kruskal-Wallis test is significant. Mann-Whitney U test was used to compare between micro-shear bond strength before and after thermocycling P ≤ 0.05. Results: In non-aged subgroups, there was no significant difference between Panavia and Activa; both showed significantly the highest mean µSBS values (22.9 MPa, 31.3 MPa respectively). While, RMGI showed the lowest µSBS values (4.7 MPa). In thermocycled subgroups, Panavia showed significantly the highest mean µSBS values (32.2 MPa). There was no significant difference between RMGI and Activa; both showed the lowest significant mean µSBS values (3.2 MPa and 8.7 MPa respectively). Conclusions: RMGI and Activa couldn't be considered long-term reliable materials for cementing zirconia. However, Panavia provided the most durable bond to zirconia. (AU)

Objetivo: O objetivo do estudo foi avaliar a resistência de união ao microcisalhamento de diferentes cimentos à zircônia translúcida antes e após o envelhecimento da termociclagem. Material e métodos: Doze discos de zircônia translúcidos foram utilizados no estudo. As amostras foram jateadas com partículas de óxido de alumínio de 50 µm (Al2 O3 ). Os espécimes foram divididos em três grupos (n = 4), de acordo com o tipo de cimento: cimento resinado Panavia (grupo controle), ionômero de vidro modificado por resina (RMGI) e cimento bioativo Activa. Cada grupo foi subdividido em dois subgrupos iguais (n = 2), dependendo se as amostras foram submetidas ou não a termociclagem. A termociclagem foi realizada em água destilada a 5000 ciclos entre 5°C - 55°C. O teste de resistência de união por microcisalhamento (µSBS) foi medido usando uma máquina de teste universal. O teste de Kruskal-Wallis foi utilizado para comparar os três cimentos. O teste de Dunn foi usado para comparações entre pares quando o teste de Kruskal-Wallis foi significativo. O teste U de Mann-Whitney foi utilizado para comparar a resistência de união ao microcisalhamento antes e após a termociclagem (P ≤ 0,05). Resultados: Nos subgrupos sem envelhecimento por termociclagem, não houve diferença significativa entre Panavia e Activa; ambos mostraram significativamente os maiores valores médios de µSBS (22,9 MPa, 31,3 MPa, respectivamente). Por sua vez, o RMGI apresentou os menores valores de µSBS (4,7 MPa). Nos subgrupos termociclados, Panavia mostrou significativamente os maiores valores médios de µSBS (32,2 MPa). Não houve diferença significativa entre RMGI e Activa; ambos apresentaram os menores valores médios significativos de µSBS (3,2 MPa e 8,7 MPa, respectivamente). Conclusões: RMGI e Activa não puderam ser considerados materiais confiáveis para cimentação à zircônia a longo prazo. No entanto, a Panavia apresentou a ligação mais durável à zircônia. (AU)

Effect of Decontamination Treatments on Micro-Shear Bond Strength between Blood-Saliva-Contaminated Post-Etched Dentin Substrate and Composite Resin.

Blood-saliva contamination negatively affects the bonding potential of adhesive agents. The study aimed to assess the effect of various cleaning protocols on micro-shear bond strength (µSBS) between blood-saliva-contaminated post-etched dentin and composite resin in total-etch and self-etch adhesives. The cleaning methods tested were water rinsing, 37.5% phosphoric acid (H3PO4) re-etching, 6% sodium hypochlorite (NaoCl), 2% chlorhexidine gluconate (CXG), isopropyl alcohol (IPA), and pumice. Nono-hybrid composite cylinders with a 3-mm diameter and 2-mm height were directly cured over the dentin substrate, stored for 24 h, and subjected to 12,000 thermocycles. The shear force was exerted with a 200-µm knife-edged chisel-shaped head from a universal testing machine. The type of failure was assessed with stereomicroscope magnified images. The obtained data were evaluated by Kruskal-Wallis and Mann-Whitney U post-hoc tests. Water-rinsed contaminated dentin surfaces showed substantially reduced µSBS in the total etch from 25.93 to 20.29 Mpa and the corresponding values for the one-step self-etch adhesive were 10.10 to 8.8. Re-etching with 37.5% H3Po4 resulted in a recovery of bonding potential in both total-etch (24.58 Mpa) and self-etch adhesive (9.23 Mpa). Alternately, NaoCl and pumice cleaning showed promising results for the total-etch (23.51 Mpa) and self-etch (7.79 Mpa).

Effect of tribochemical silica coating or multipurpose products on bonding performance of a CAD/CAM resin-based material.

OBJECTIVES: Nanocomposite ceramics have been widely used in clinical practice; however, a standard, recommended bonding protocol has not been determined yet. The present study aimed to evaluate application of tribochemical silica coating or multipurpose products on bonding performance of a CAD/CAM resin-based material (known as nanocomposite ceramic). MATERIALS AND METHODS: Nanocomposite ceramic specimens were fabricated and assigned into 11 groups to build bonded specimens (n = 15) according to surface treatments (none; air particle abrasion with 50-µm alumina followed by application of a silane coupling agent or a universal adhesive; tribochemical silica coating followed by application of a silane coupling agent or a universal adhesive) and resin luting cements (conventional resin cement, RelyX Veneer; self-adhesive resin cement RelyX Unicem) used. Micro-shear bond strength (µ-SBS) was measured after 24-h water storage or ageing with 10,000 thermocycles plus additional 90-d water storage. Surface roughness after alumina air abrasion and tribochemical silica coating were determined using a profilometer. Surface morphology and element variation were observed by using a scanning electron microscope (SEM)/energy dispersion spectrum (EDS). X-ray photoelectron spectroscopy (XPS) was used to characterize nanocomposite ceramic powders conditioned with silane coupling agent or the universal adhesive used in the µ-SBS test. The nanocomposite ceramic plates received alumina air abrasion, tribochemical silica coating, or without, were determined using X-ray diffraction (XRD). RESULTS: Nanocomposite ceramic treated with alumina air abrasion achieved the highest surface roughness, followed by those treated with tribochemical silica coating. Newly formed Si-O-Si bonds on the nanocomposite ceramic surface were detected by XPS after treatment with silane coupling agent or universal adhesive, and a Zr-O-P bond was detected after treating with universal adhesive. µ-SBS was significantly affected by bond strategies and ageing. Ageing by thermocycling and water storage significantly decreased µ-SBS. µ-SBS values derived by use of a universal adhesive or self-adhesive resin cement alone were no lower than the values derived by use of a silane coupling agent alone. Pre-silanization further enhanced the bonding improvement of universal adhesive or self-adhesive resin cement. However, tribochemical silica coating failed to provide higher µ-SBS compared with alumina air abrasion. XRD detected no monoclinic zirconia phase after alumina air abrasion or tribochemical silica coating, suggesting that these two roughening methods did not lead to phase transformation of zirconia fillers. CONCLUSIONS: Combination of presilanization and universal adhesives improve resin bonding of nanocomposite ceramics. Tribochemical silica coating is not superior to alumina air abrasion for pretreated nanocomposite ceramics.

Effect of smear layer and surface roughness on resin-dentin bond strength of self-etching adhesives.

The purpose of this study was to evaluate the effect of surface roughness and smear layer on the micro-shear bond strength (µSBS) of two self-etching adhesives, Clearfil SE Bond (SE) and Clearfil Tri-S Bond (S3). Flat dentin surfaces were prepared with SiC papers (600-, 180- and 120-grit) and diamond burs (extra fine, medium and coarse). They were further divided into smear-covered and smear-free surfaces and bonded with respective adhesives. µSBS test was performed after water storage at 37ºC for 24 h. Smear layer thickness measurement was evaluated by scanning electron microscope (SEM). Surface roughness was examined by contact stylus profilometer. Smear layer thickness and surface roughness were significantly different among all groups (p<0.05). No difference in µSBS was observed among surface prepared by SiC whereas bur-cut smear layer had negative effect on µSBS, especially for S3. Surface roughness from different surface preparations had no influence on µSBS (p<0.05).

Bonding performance of universal adhesives on composite repairs, with or without silane application.

AIM: This study aims to investigate the adhesive performance of three different universal adhesives to repair aged composite restorations, with or without the application of silane. MATERIALS AND METHODS: A hundred and twenty resin composite samples were prepared, aged and randomly divided into 6 main Groups (single bond universal [SBU], All-Bond Universal [ABU], Futurabond U, Clearfil Tri-S Bond, Single Bond 2, and Clearfil SE Bond) and 2 subgroups (with or without silane). A microhybrid composite resin was placed on the aged composite surfaces and light cured. After a micro-shear bonding test, the fracture surfaces were examined under the scanning electron microscopy. Statistical analysis was performed using two-way ANOVA and Tukey's post hoc tests. RESULTS: Among all the universal adhesives, SBU showed the highest bond strength values compared to the other two universal adhesives when used with and without silane (P > 0.05). Between ABU and Futurabond U, no significant difference was observed with silane (P > 0.05) and without silane (P > 0.05). Among conventional adhesives, there was no statistically significant difference (P > 0.05) both with and without silane. CONCLUSION: Within the limitations of this study, while SBU can be safely used with and without the application of silane, Futurabond U cannot be used without silane.