Effect of shelf-life of a universal adhesive to dentin

The microtensile bond strength (\u3bcTBS), nanoleakage expression (NL), and endogenous enzymatic activity of a simplified universal adhesive system used in combination with a dual-cure resin cement for luting indirect restorations were evaluated considering its shelf-life (as-received vs expired). The universal adhesive was used asreceived (AS-R) by manufacturer or after three months after being expired (EXP). Resin composite overlays (n \ubc 10) were luted to flat deep coronal dentin surfaces with a universal bonding system (iBond universal, used in the self-etch mode) in combination with a dual-cure resin cement (RelyX Ultimate; 20s of light-cure followed by 15 min of self-cure at 37 \ufffdC). After 24 h, the specimens were cut into microtensile sticks (1 mm2) and stressed to failure under tension, in accordance with ISO/TS 11.405. The fracture pattern was evaluated with optical microscopy. The significance level of p \ubc 0.05 was used for the statistical analysis. Additional specimens (n \ubc 4) were processed for quantitative interfacial nanoleakage expression using ammoniacal silver nitrate. To investigate the endogenous enzymatic activity within the hybrid layer in situ zymography was performed. The EXP group obtained significantly lower \u3bcTBS values than those recorded in the AS-R group (p < 0.05). NL resulted in higher deposition of AgNO3 granules when the adhesive was used in the EXP group compared to the AS-R bonding system. In situ zymography assay revealed increased level of fluorescence when the universal bonding system was used at the end of shelf-life compared to the AS-R group. The use of the universal adhesive system beyond the expiry limit resulted in decreased bonding performances. Furthermore, the higher endogenous enzymatic activity recorded after the end of the shelf life of the universal adhesive would portend for a shortened durability of the restorations

Does immediate dentin sealing influence postoperative sensitivity in teeth restored with indirect restorations?:A systematic review and meta-analysis

OBJECTIVE: This study comprehensively reviewed clinical trials that investigated the effect of immediate dentin sealing (IDS) technique on postoperative sensitivity (POS) and clinical performance of indirect restorations. MATERIALS AND METHODS: The systematic review was conducted according to the preferred reporting items for systematic reviews and meta‐analyses statement, and was guided by the PICOS strategy. Clinical trials in which adult patients received at least one indirect restoration cemented with IDS approach and one restoration cemented following the delayed dentin sealing (DDS) were considered. RESULTS: Following title screening and full‐text reading, four studies met the inclusion criteria and were included for qualitative synthesis, while two studies were selected for quantitative synthesis. According to Risk of bias‐2 tool, two studies were classified as “some concerns” for the outcome POS. No statistically significant differences were found between teeth restored with indirect restorations using the IDS and DDS approach for POS (p > 0.05), neither at the baseline (very low certainty of evidence according to GRADE) nor after 2 years of follow‐up (low certainty of evidence according to GRADE). CONCLUSION: There is low‐certainty evidence that IDS does not reduce POS in teeth restored with indirect restorations. CLINICAL SIGNIFICANCE: There is no clinical evidence to favor IDS over DDS when restoring teeth with indirect restorations

The effect of carbodiimide on push-out bond strength of fiber posts and endogenous enzymatic activity

BackgroundTo investigate the effect of 0.3 M 1-ethyl-3(3-dimethylaminopropyl) carbodiimide (EDC) aqueous solution pretreatment on push-out bond strength (PBS) and matrix-metalloproteinases (MMPs) activity within radicular dentin when different post cementation strategies were employed.MethodsOne hundred and twenty monoradicular human teeth were endodontically treated and randomly divided into six groups, depending on the cementation strategy and root dentin pretreatment (n = 20): EAR: cementation with an etch-and-rinse adhesive (LuxaBond Total Etch, DMG) and resin cement (LuxaCore Z Dual, DMG); EAR/EDC: 1 min EDC pretreatment after etching + EAR; SE: cementation with a self-etch primer (Multilink Primer, Ivoclar Vivadent) and corresponding cement (Multilink Automix, Ivoclar Vivadent); SE/EDC: self-etch primer + EDC pretreatment + SE; SA: cementation with a universal self-adhesive cement (RelyX Universal, 3 M); SA/EDC: EDC pretreatment + SA. Slices were submitted to PBS test and interfacial nanoleakage evaluation 24 h after cementation or after thermocycling (40.000 cycles, 5-55 & DEG;C). To investigate the effect of EDC on MMPs activity, 4 additional first maxillary premolars per group were processed for in situ zymography analysis. Multivariate ANOVA and post hoc Tukey tests were used to analyze PBS values. The data from in situ zymography were analyzed with Kruskal-Wallis test and Dunn's pairwise multiple comparison procedures (& alpha; = 0.05).ResultsThe variables "EDC pretreatment", "root region" and "thermocycling" significantly influenced PBS (p < 0.05), while the variable "cementation strategy" had no influence (p > 0.05). Thermocycling significantly reduced PBS in SE and SA groups (p < 0.05). EDC was effective in preserving PBS after artificial aging. EDC pretreatment significantly reduced enzymatic activity at baseline in EAR and SE groups, and in SA group after thermocycling (p < 0.05).ConclusionsThe use of EDC prevents the reduction of bond-strength values after artificial aging and silences endogenous enzymatic activity within radicular dentin when different cementation strategies were employed

Revisão de literatura : adesão aos tecidos dentais e uso do EDTA como agente de condicionamento dentinário

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Dentin-resin bond evaluation using different dentin conditioning approaches

Orientador: Marcelo GianniniDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: Este estudo avaliou os efeitos de diferentes condicionadores dentinários (ácido fosfórico 37%; solução 10:3; oxalato férrico e ácido nítrico) na resistência de união por microtração de dois adesivos, na resistência à flexão e módulo de elasticidade da dentina e na morfologia da área de união resina-dentina. Dois adesivos foram testados: XP Bond (Dentsply) e One-Step (Bisco). Os agentes de união foram aplicados sobre dentina umedecida (controle positivo) e seca (controle negativo) após condicionamento com ácido fosfórico. Os grupos experimentais consistiram na aplicação dos adesivos sobre superfície seca após condicionamento dentinário com solução 10:3, oxalato férrico 6,8% ou ácido nítrico 1,4%. Oitenta terceiros molares humanos foram divididos em 10 grupos para o teste de microtração (n=8). Para o teste de resistência à flexão e módulo de elasticidade, foram utilizados 25 incisivos bovinos, dos quais foram obtidas barras de dentina com dimensões de 0,5 mm x 1,7 mm x 7 mm. A área de união foi analisada sob microscópio confocal de varredura a laser, preparando-se 30 dentes para os mesmos grupos do teste de resistência de união (n=3). Os dados de resistência de união foram analisados por ANOVA dois fatores (tratamento dentinário e tipo de adesivo), enquanto que os resultados do teste de flexão foram analisados por ANOVA um fator (tratamento dentinário). Ambos os ensaios foram submetidos ao Teste de Tukey. As estruturas observadas na avaliação microscópica foram descritas e comparadas entre os grupos. A aplicação de XP Bond após tratamento dentinário com solução 10:3 apresentou resistência de união menor que o grupo controle positivo e nenhuma diferença estatística em relação ao grupo controle negativo do mesmo adesivo. A solução 10:3 associada com One-Step resultou em resistência de união semelhante ao controle positivo e maior que o controle negativo do mesmo adesivo. O condicionamento com ácido nítrico, acompanhado pela aplicação de XP Bond produziu resistência de união menor que ambos os grupos controle deste adesivo. Os valores de resistência de união encontrados para a associação entre ácido nítrico e One-Step foram maiores que o controle negativo e similares ao controle positivo do One-Step. Formação de camada híbrida e tags resinosos ocorreu em todos os dentes tratados com solução 10:3 ou ácido nítrico. O oxalato férrico não foi capaz de promover hibridização, resultando na menor resistência de união para o adesivo XP Bond. A resistência de união obtida pelo uso de One-Step em dentina tratada com oxalato férrico não apresentou diferença comparado com o controle negativo do One-Step. O módulo de elasticidade da dentina não foi afetado por nenhum dos agentes utilizados. Redução na resistência à flexão da dentina foi observada somente para o oxalato férrico. Conclui-se que: para o adesivo One-Step, união resina-dentina similar ao grupo no qual o sistema de união foi aplicado sobre dentina umedecida previamente condicionada com ácido fosfórico pode ser obtida pelo uso da solução 10:3 ou do ácido nítrico; os condicionadores dentinários testados não foram capazes de afetar a rigidez da dentina; a resistência à flexão da dentina foi prejudicada pelo tratamento da superfície com oxalato férricoAbstract: This study evaluated the effects of different dentin conditioners (37% phosphoric acid; 10-3 solution; ferric oxalate, and nitric acid) on the microtensile bond strength of two adhesive systems, flexural strength and elastic modulus of dentin and the morphology of the resin-dentin interface. Two bonding systems were tested: XP Bond (Dentsply) and One-Step (Bisco). The adhesives were applied on wet (positive control group) and dry (negative control group) dentin after phosphoric acid-etching. The experimental groups consisted in the application of adhesives on dry surfaces after dentin conditioning with 10-3 solution, 6.8% ferric oxalate or 1.4% nitric acid. Eighty human third molars were divided into 10 experimental groups for the bond strength test (n=8). The flexural strength and elastic modulus test required the use of 25 bovine incisors, which were reduced to dentin bars with dimensions of 0.5 mm x 1.7 mm x 7 mm. Adhesive interface analysis was performed under laser scanning confocal microscopy by preparing 30 teeth for the same groups from the bond strength test (n=3). Bond strength data were analyzed by two-way ANOVA (dentin treatment and type of adhesive), whereas results from the flexural strength test were analyzed by one-way ANOVA (dentin treatment). Both strength assays were subjected to the Tukey test. The structures observed in the microscopic evaluation were described and compared amongst groups. Application of XP Bond after dentin treatment with 10-3 solution showed lower bond strength than the positive control group and no statistical difference was detected compared to the negative control group within the same adhesive. Ten-three solution associated with One-Step resulted in bond strength statistically similar to the positive control group and higher than the negative control group of the same bonding system. Nitric acid-conditioning followed by the application of XP Bond produced lower bond strength in comparison to both control groups of XP Bond. Bond strength values found for the association between nitric acid and One-Step were higher than the negative control group and statistically similar to the positive control group of One-Step. Hybrid layer and resin tags formation occurred in all teeth treated with 10-3 solution or nitric acid. Ferric oxalate was not capable to promote hybridization and resulted in the lowest bond strength for XP Bond. Bond strength obtained by the use of One-Step on ferric oxalate-treated dentin presented no statistical differences compared to the negative control group. Dentin elastic modulus was not affected by any of the conditioning agents used. A reduction in dentin flexural strength was observed only for the ferric oxalate group. In conclusion: for the adhesive One-Step, resin-dentin bonds similar to the group where the bonding agent was applied on wet, phosphoric acid-etched dentin can be achieved by the use of 10-3 solution or nitric acid; the conditioning agents tested were not able to affect dentin stiffness; flexural strength was jeopardized by surface treatment with ferric oxalateMestradoDentísticaMestre em Clínica Odontológica2015/03927-3FAPES

Surface roughness and filler particles characterization of resin‐based composites

The purpose of this study was to evaluate the surface roughness (Ra), and the morphology and composition of filler particles of different composites submitted to toothbrushing and water storage. Disc‐shaped specimens (15 mm × 2 mm) were made from five composites: two conventional (Z100™, and Filtek™ Supreme Ultra Universal, 3M), one “quick‐cure” (Estelite ∑ Quick, Tokuyama), one fluoride‐releasing (Beautiful II, Shofu), and one self‐adhering (Vertise Flow, Kerr) composite. Samples were finished/polished using aluminum oxide discs (Sof‐Lex, 3M), and their surfaces were analyzed by profilometry (n = 5) and scanning electron microscopy (SEM; n = 3) at 1 week and after 30,000 toothbrushing cycles and 6‐month water storage. Ra data were analyzed by two‐way analysis of variance and Tukey's test (α = 0.05). Filler particles morphology and composition were analyzed by SEM and X‐ray dispersive energy spectroscopy, respectively. Finishing/polishing resulted in similar Ra for all the composites, while toothbrushing and water storage increased the Ra of all the tested materials, also changing their surface morphology. Beautifil II and Vertise Flow presented the highest Ra after toothbrushing and water storage. Filler particles were mainly composed of silicon, zirconium, aluminum, barium, and ytterbium. Size and morphology of fillers, and composition of the tested composites influenced their Ra when samples were submitted to toothbrushing and water storage821017561767FAPESP – Fundação de Amparo à Pesquisa Do Estado De São Paulo2011/21670-9Art, science, microscopy and ED

Dry-bonding to dentin using alternative conditioners based on iron-containing solutions or nitric acid

To evaluate the effect of experimental conditioners (10-3 solution - 10-3, 6.8% ferric oxalate - FOX, and 1.4% nitric acid - NI) on dentin elastic modulus, flexural strength, bond strength, failure mode, and adhesive interface morphology of two etch-and-rinse adhesives (XP Bond, Dentsply or One-Step, Bisco) applied on etched thy dentin. Methods: Sound human third molars were used for the microtensile bond strength test (n = 8), performed at 24 h and after one year of water storage. Failure modes were evaluated by scanning electron microscopy. Dentin bonding interface was analyzed by confocal laser scanning microscopy (n = 3). Adhesive systems were applied on phosphoric acid-etched, wet (positive control) and dry (negative control) dentin, and on etched and dry dentin previously treated with 10-3 (15s), FOX (60s), or NI (15s). Bovine dentin bars (n = 15) were immersed into the conditioning solutions and subjected to a three-point bending test. Results: XP Bond + 10-3 or NI resulted in lower bond strength than phosphoric acid. One-Step + 10-3 or NI resulted in bond strengths equivalent to the positive control. Experimental conditioners presented no bond strength reduction after one year, regardless of the bonding agent tested. One-Step resulted in more adhesive failures than XP Bond at 24 h, and mixed failures increased after storage. All experimental conditioners promoted hybridization and resin tags formation, except FOX. Dentin elastic modulus was not affected by the conditioners, whereas flexural strength was significantly reduced by FOX. Conclusions: Adequate and stable dentin bonds were achieved when the bonding agents were applied on 10-3 or NI-treated dentin. None of the experimental conditioners reduced dentin elastic modulus, but dentin flexural strength was significantly reduced by FOX-conditioning94238248FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2015/03927-

Multiple-peak and single-peak dental curing lights comparison on the wear resistance of bulk-fill composites

Abstract: The effects of tooth brushing could affect the long-term esthetic outcome of composite restorations. This study evaluated the effect of two different emission spectrum light-curing units on the surface roughness, roughness profile, topography and microhardness of bulk-fill composites after in vitro toothbrushing. Valo (multiple-peak) and Demi Ultra (single-peak) curing lights were each used for 10s to polymerize three bulk-fill resin composites: Filtek Bulk Fill Posterior Restorative (FBF), Tetric EvoCeram Bulk Fill (TET) and Surefil SDR Flow (SDR). After 30,000 reciprocal strokes in a toothbrushing machine, the roughness profile, surface roughness, surface morphology, and microhardness were examined. Representative SEM images were also obtained. When light-cured with the Demi Ultra, SDR showed the most loss in volume compared to the other composites and higher volume loss compared to when was light-cured with Valo. The highest surface roughness and roughness profile values were found in SDR after toothbrushing, for both light-curing units tested. FBF always had the greatest microhardness values. Light-curing TET with Valo resulted in higher microhardness compared to when using the Demi Ultra. Confocal and SEM images show that toothbrushing resulted in smoother surfaces for FBF and TET. All composites exhibited surface volume loss after toothbrushing. The loss in volume of SDR depended on the light-curing unit used. Toothbrushing can alter the surface roughness and superficial aspect of some bulk-fill composites. The choice of light-curing unit did not affect the roughness profile, but, depending on the composite, it affected the microhardness