Effect Of Storage Time On Bond Strength And Nanoleakage Expression Of Universal Adhesives Bonded To Dentin And Etched Enamel

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)To investigate bond strength and nanoleakage expression of universal adhesives (UA) bonded to dentin and etched enamel. Methods: Extracted human third molars were sectioned and ground to obtain flat surfaces of dentin (n = 36) and enamel (n = 48). Dentin and etched enamel surfaces were bonded with one of two UAs, All-Bond Universal (ABU) or Scotchbond Universal (SBU); or a two-step self-etching adhesive, Clearfil SE Bond (CSEB). A hydrophobic bonding resin, Adper Scotchbond Multi-Purpose Bond (ASMP Bond) was applied only on etched enamel. Following each bonding procedure, resin composite blocks were built up incrementally. The specimens were sectioned and subjected to microtensile bond strength (MTBS) testing after 24 hours or one year water storage, or immersed into ammoniacal silver nitrate solution after aging with 10,000 thermocycles and observed using scanning electron microscopy. The percentage distribution of silver particles at the adhesive/tooth interface was calculated using digital image-analysis software. Results: The MTBS (CSEB = SBU > ABU, for dentin; and CSEB > ABU = SBU = ASMP Bond, for etched enamel) differed significantly between the adhesives after 24 hours. After one year, MTBS values were reduced significantly within the same adhesive for both substrates (analysis of variance, Bonferroni post hoc, p0.05). Conclusions: In the short term, MTBS values were material and dental-substrate dependent. After aging, a decrease in bonding effectiveness was observed in all materials, with nanoleakage at the adhesive/dentin interface. The bonding of the UAs was equal or inferior to that of the conventional restorative systems when applied to either substrate and after either storage period.41305317Brazilian National Council for Scientific and Technological Development (CNPq) [307217-2014-0]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Self-etch Adhesive Systems: A Literature Review

This paper presents the state of the art of self-etch adhesive systems. Four topics are shown in this review and included: the historic of this category of bonding agents, bonding mechanism, characteristics/properties and the formation of acid-base resistant zone at enamel/dentin-adhesive interfaces. Also, advantages regarding etch-and-rinse systems and classifications of self-etch adhesive systems according to the number of steps and acidity are addressed. Finally, issues like the potential durability and clinical importance are discussed. Self-etch adhesive systems are promising materials because they are easy to use, bond chemically to tooth structure and maintain the dentin hydroxyapatite, which is important for the durability of the bonding.261310Brudevold, F., Buonocore, M., Wileman, W., A report on a resin composition capable of bonding to human dentin surfaces (1956) J Dent Res, 35, pp. 846-851Kramer, J., McLan, J.W., Alterations in the staining reactions of dentine resulting from a constituent of a new self-polymerizing resin (1952) Brit Dent J, 93, pp. 150-153Chigira, H., Yukitani, W., Hasegawa, T., Manabe, A., Itoh, K., Hayakawa, T., Debari, K., Hisamitsu, H., Self-etching dentin primers containing Phenyl-P (1994) J Dent Res, 73, pp. 1088-1095Watanabe, I., Nakabayashi, N., Pashley, D.H., Bonding to ground dentin by a phenyl-P self-etching primer (1994) J Dent Res, 73, pp. 1212-1220Van Landuyt, K.L., Snauwaert, J., De Munck, J., Peumans, M., Yoshida, Y., Poitevin, A., Systematic review of the chemical composition of contemporary dental adhesives (2007) Biomaterials, 28, pp. 3757-3785Tay, F.R., King, N.M., Chan, K., Pashley, D.H., How can nanoleakage occur in self-etching adhesive systems that demineralize and infiltrate simultaneously? (2002) J Adhes Dent, 4, pp. 255-269Van Meerbeek, B., De Munck, J., Yoshida, Y., Inoue, S., Vargas, M., Vijay, P., Adhesion to enamel and dentin: Currents status and future challenges (2003) Oper Dent, 28, pp. 215-235Reis, A.F., Giannini, M., Pereira, P.N., Long-Term, T., Analysis of the nanoleakage patterns in resin-dentin interfaces produced by different bonding strategies (2007) Dent Mate, 23, pp. 1164-1172Van Meerbeek, B., Yoshihara, K., Yoshida, Y., Mine, A., De Munck, J., Van Landuyt, K.L., State of the art of self-etch adhesives (2011) Dent Mater, 27, pp. 17-28Tay, F.R., Pashley, D.H., Aggressiveness of contemporary self-etching systems. I: Depth of penetration beyond dentin smear layers (2001) Dent Mater, 17, pp. 296-308Tay, F.R., Pashley, D.H., Suh, B.I., Carvalho, R.M., Itthagarun, A., Single-step adhesives are permeable membranes (2002) J Dent, 30, pp. 371-382Tay, F., Pashley, D.H., Have dentin adhesives become too hydrophilic? 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Bonding effectiveness of a new ‘multi-mode’ adhesive to enamel and dentine (2012) J Dent, 40, pp. 475-484Perdigao, J., Loguercio, A.D., (2014) Universal Or Multi-Mode Adhesives: Why and How? J Adhes Dent, 16, pp. 193-194Van Meerbeek, B., Peumans, M., Poitevin, A., Mine, A., Van Ende, A., Neves, A., Relationship between bond-strength tests and clinical outcomes (2010) Dent Mater, 26, pp. e100-e121Moszner, N., Salz, U., Zimmermann, J., Chemical aspects of selfetching enamel-dentin adhesives: A systematic review (2005) Dent Mater, 21, pp. 895-910Perdigao, J., Lopes, M.M., Gomes, G., In vitro bonding performance of self-etch adhesives (2008) Ii--Ultramorphological Evaluation. 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Influence of MDPB-containing primer on Streptococcus mutans biofilm formation in simulated Class I restorations (2013) J Adhes Dent, 15, pp. 431-438Izutani, N., Imazato, S., Nakajo, K., Takahashi, N., Takahashi, Y., Ebisu, S., . Effects of the antibacterial monomer 12-methacryloyloxydodecylpyridinium bromide (MDPB) on bacterial viability and metabolism (2011) Eur J Oral Sci, 119, pp. 175-181Nishiyama, N., Asakura, T., Suzuki, K., Komatsu, K., Nemoto, K., Bond strength of resin to acid-etched dentin studied by 13C NMR: Interaction between N-methacryloyl-omega-amino acid primer and dentinal collagen (2000) J Dent Res, 79, pp. 806-811Yoshida, H., Nishiyama, N., Development of self-etching primer comprised of methacrylamide, N-methacryloyl glycine (2003) Biomaterials, 24, pp. 5203-5207Nishiyama, N., Suzuki, K., Yoshida, H., Teshima, H., Nemoto, K., Hydrolytic stability of methacrylamide in acidic aqueous solution (2004) Biomaterials, 25, pp. 965-969Shinohara, M.S., De Oliveira, M.T., Di Hipolito, V., Giannini, M., De Goes, M.F., SEM analysis of the acid-etched enamel patterns promoted by acidic monomers and phosphoric acids (2006) J Appl Oral Sci, 14, pp. 427-435Luhrs, A.K., Guhr, S., Schilke, R., Borchers, L., Geurtsen, W., Gunay, H., Shear bond strength of self-etch adhesives to enamel with additional phosphoric acid etching (2008) Oper Dent, 33, pp. 155-162Erickson, R.L., Barkmeier, W.W., Kimmes, N.S., Bond strength of self-etch adhesives to pre-etched enamel (2009) Dent Mater, 25, pp. 1187-1194Devarasa, G.M., Subba Reddy, V.V., Chaitra, N.L., Swarna, Y.M., (2012) Self-Etching Adhesive on Intact Enamel, with and without Pre-Etching Microsc Res Tech, 75, pp. 650-654Peumans, M., De Munck, J., Van Landuyt, K.L., Poitevin, A., Lambrechts, P., Van Meerbeek, B., Eight-year clinical evaluation of a 2-step self-etch adhesive with and without selective enamel etching (2010) Dent Mater, 26, pp. 1176-1184Can Say, E., Yurdaguven, H., Ozel, E., Soyman, M., A randomized five-year clinical study of a two-step self-etch adhesive with or without selective enamel etching (2014) Dent Mater J, 11. , Epub ahead of printPeumans, M., De Munck, J., Mine, A., Van Meerbeek, B., Clinical effectiveness of contemporary adhesives for the restoration of non-carious cervical lesions. A systematic review (2014) Dent Mater, 30, pp. 1089-1103Bakry, A.S., Sadr, A., Inoue, G., Otsuki, M., Tagami, J., Effect of Er:YAG laser treatment on the microstructure of the dentin/adhesive interface after acid-base challenge (2007) J Adhes Dent, 9, pp. 513-520Tsuchiya, S., Nikaido, T., Sonoda, H., Foxton, R.M., Tagami, J., Ultrastructure of the dentin-adhesive interface after acid-base challenge (2004) J Adhes Dent, 6, pp. 183-190Inoue, G., Tsuchiya, S., Nikaido, T., Foxton, R.M., Tagami, J., Morphological and mechanical characterization of the acid-base resistant zone at the adhesive-dentin interface of intact and caries-affected dentin (2006) Oper Dent, 31, pp. 466-472Waidyasekera, K., Nikaido, T., Weerasinghe, D.S., Ichinose, S., Tagami, J., Reinforcement of dentin in self-etch adhesive technology: A new concept (2009) J Dent, 37, pp. 604-609Nikaido, T., Weerasinghe, D.D., Waidyasekera, K., Inoue, G., Foxton, R.M., Tagami, J., Assessment of the nanostructure of acid-base resistant zone by the application of all-in-one adhesive systems: Super dentin formation (2009) Biomed Mater Engineer, 19, pp. 163-171Takagaki, T., Nikaido, T., Tsuchiya, S., Ikeda, M., Foxton, R.M., Tagami, J., Effect of hybridization on bond strength and adhesive interface after acid-base challenge using 4-META/MMA-TBB resin (2009) Dent Mater J, 28, pp. 185-193Iida, Y., Nikaido, T., Kitayama, S., Takagaki, T., Inoue, G., Ikeda, M., . 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Endogenous Galectin-9 Suppresses Apoptosis in Human Rheumatoid Arthritis Synovial Fibroblasts

Galectin-9 (Gal9) has been postulated to have anti-infammatory properties based on the ability of exogenous Gal9 to induce apoptosis in synovial fbroblasts in animal models of rheumatoid arthritis (RA). Here we aimed to assess the potential role of endogenous Galectins, including Gal9, in the infammatory pathology of the RA synovium in humans. Firstly expression of Galectins 1–9 was determined in synovial fbroblasts (RASF) and dermal fbroblasts (DF) isolated from RA patients, the latter representing a non-infamed site. We then further challenged the cells with pro-infammatory TLR agonists and cytokines and assessed Galectin expression. Gal9 was found to be diferentially and abundantly expressed in RASF compared to DF. Agonists of TLR3 and TLR4, along with IFNgamma were also found to induce Gal9 expression in RASF. siRNA was then used to knock-down Gal9 expression in RASF and the efects of this on apoptosis and cell viability were assessed. Increased apoptosis was observed in RASF following Gal9 knock-down. We conclude that, unlike exogenous Gal9, endogenous Gal9 is protective against apoptosis and enhances synovial fbroblast viability suggesting that its role in RA is both pathogenic and pro-infammatory

Comparison of the marginal adaptation of direct and indirect composite inlay restorations with optical coherence tomography

OBJECTIVE: The purpose of the study was to use the photonic imaging modality of optical coherence tomography (OCT) to compare the marginal adaptation of composite inlays fabricated by direct and indirect techniques. MATERIAL AND METHODS: Class II cavities were prepared on 34 extracted human molar teeth. The cavities were randomly divided into two groups according to the inlay fabrication technique. The first group was directly restored on cavities with a composite (Esthet X HD, Dentsply, Germany) after isolating. The second group was indirectly restored with the same composite material. Marginal adaptations were scanned before cementation with an invisible infrared light beam of OCT (Thorlabs), allowing measurement in 200 µm intervals. Restorations were cemented with a self-adhesive cement resin (SmartCem2, Dentsply), and then marginal adaptations were again measured with OCT. Mean values were statistically compared by using independent-samples t-test and paired samples t-test (p<0.05), before and after cementation. RESULTS: Direct inlays presented statistically smaller marginal discrepancy values than indirect inlays, before (p=0.00001442) and after (p=0.00001466) cementation. Marginal discrepancy values were increased for all restorations after cementation (p=0.00008839, p=0.000000952 for direct and indirect inlays, respectively). The mean marginal discrepancy value of the direct group increased from 56.88±20.04 µm to 91.88±31.7 µm, whereas the indirect group increased from 107.54±35.63 µm to 170.29±54.83 µm. Different techniques are available to detect marginal adaptation of restorations, but the OCT system can give quantitative information about resin cement thickness and its interaction between tooth and restoration in a nondestructive manner. CONCLUSIONS: Direct inlays presented smaller marginal discrepancy than indirect inlays. The marginal discrepancy values were increased for all restorations that refer to cement thickness after cementation

Effect Of Storage Time On Bond Strength Performance Of Multimode Adhesives To Indirect Resin Composite And Lithium Disilicate Glass Ceramic

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)To investigate the bond strength performance of multimode adhesives (MMAs) to indirect resin composite and lithium disilicate glass ceramic after 24 hours or one year of water storage. Methods and Materials: Thirty flat and polished plates of indirect resin composite (Epricord) and thirty lithium disilicate glass ceramic plates (IPS e.max Press) were prepared. Surfaces were pretreated using sandblasting (indirect resin composite) or hydrofluoric acid (glass-based ceramic). Specimens were bonded with one of two MMAs (Scotchbond Universal [SBU] or All-Bond Universal [ABU]) or ceramic primer and hydrophobic bonding (RelyX Ceramic Primer and Adper Scotchbond Multi-Purpose Bond) as a control (n=10). Resin cement cylinders (0.75 mm in diameter 3 0.5 mm in height) were bonded to both substrate surfaces using the respective adhesives. After 24 hours or one year of water storage, bonding performance was measured by microshear bond strength (MSBS) testing. Results were analyzed using three-way ANOVA with Bonferroni post hoc tests (alpha=0.05). Results: For indirect resin composite, significantly higher MSBS values were found for ABU after 24 hours (ABU > SBU = control); however, no significant difference among the adhesives was observed after one year (p > 0.05). For glass-based ceramic, significantly different bond strengths were observed among the adhesives after 24 hours (control = ABU > SBU) and one year (control > SBU = ABU; p < 0.05). Conclusions: Both MMAs tested can be considered effective alternatives for bonding to sandblasted indirect resin composite after aging, as they showed similar bond performance to that of the control group. However, separate bottles of silane bonding resin showed higher MSBS values and more durable bonding for etched glass-based ceramic.415541551Brazilian Federal Agency (CNPq) [307217/2014-0]Brazilian Federal Agency (CAPES) [840/2010]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Effect of storage time on bond strength performance of multimode adhesives to indirect resin composite and lithium disilicate glass ceramic

Purpose: To investigate the bond strength performance of multimode adhesives (MMAs) to indirect resin composite and lithium disilicate glass ceramic after 24 hours or one year of water storage. Methods and Materials: Thirty flat and polished plates of indirect resin composite (Epricord) and thirty lithium disilicate glass ceramic plates (IPS e.max Press) were prepared. Surfaces were pretreated using sandblasting (indirect resin composite) or hydrofluoric acid (glass-based ceramic). Specimens were bonded with one of two MMAs (Scotchbond Universal [SBU] or All-Bond Universal [ABU]) or ceramic primer and hydrophobic bonding (RelyX Ceramic Primer and Adper Scotchbond Multi-Purpose Bond) as a control (n=10). Resin cement cylinders (0.75 mm in diameter 3 0.5 mm in height) were bonded to both substrate surfaces using the respective adhesives. After 24 hours or one year of water storage, bonding performance was measured by microshear bond strength (MSBS) testing. Results were analyzed using three-way ANOVA with Bonferroni post hoc tests (alpha=0.05). Results: For indirect resin composite, significantly higher MSBS values were found for ABU after 24 hours (ABU > SBU = control); however, no significant difference among the adhesives was observed after one year (p > 0.05). For glass-based ceramic, significantly different bond strengths were observed among the adhesives after 24 hours (control = ABU > SBU) and one year (control > SBU = ABU; p < 0.05). Conclusions: Both MMAs tested can be considered effective alternatives for bonding to sandblasted indirect resin composite after aging, as they showed similar bond performance to that of the control group. However, separate bottles of silane bonding resin showed higher MSBS values and more durable bonding for etched glass-based ceramic415541551CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQCOORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES307217/2014-0840/201

Time Scales in Epigenetic Dynamics and Phenotypic Heterogeneity of Embryonic Stem Cells

<div><p>A remarkable feature of the self-renewing population of embryonic stem cells (ESCs) is their phenotypic heterogeneity: Nanog and other marker proteins of ESCs show large cell-to-cell variation in their expression level, which should significantly influence the differentiation process of individual cells. The molecular mechanism and biological implication of this heterogeneity, however, still remain elusive. We address this problem by constructing a model of the core gene-network of mouse ESCs. The model takes account of processes of binding/unbinding of transcription factors, formation/dissolution of transcription apparatus, and modification of histone code at each locus of genes in the network. These processes are hierarchically interrelated to each other forming the dynamical feedback loops. By simulating stochastic dynamics of this model, we show that the phenotypic heterogeneity of ESCs can be explained when the chromatin at the <i>Nanog</i> locus undergoes the large scale reorganization in formation/dissolution of transcription apparatus, which should have the timescale similar to the cell cycle period. With this slow transcriptional switching of <i>Nanog</i>, the simulated ESCs fluctuate among multiple transient states, which can trigger the differentiation into the lineage-specific cell states. From the simulated transitions among cell states, the epigenetic landscape underlying transitions is calculated. The slow <i>Nanog</i> switching gives rise to the wide basin of ESC states in the landscape. The bimodal Nanog distribution arising from the kinetic flow running through this ESC basin prevents transdifferentiation and promotes the definite decision of the cell fate. These results show that the distribution of timescales of the regulatory processes is decisively important to characterize the fluctuation of cells and their differentiation process. The analyses through the epigenetic landscape and the kinetic flow on the landscape should provide a guideline to engineer cell differentiation.</p></div