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Bonding of adhesive luting agents to caries-affected dentin
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d e n t a l m a t e r i a l s 3 0 S ( 2 0 1 4 ) e1–e180
263 Bonding of adhesive luting agents to caries-affected dentin A.C. Peixoto 1 , A.A. Bicalho 2 , C.P. Isolan 3 , T.T. Maske 3 , C.J. Soares 2 , R.R. Moraes 3 , M.S. Cenci 3 , A.L. Faria-E-Silva 1,∗ 1
Federal University of Sergipe, Brazil Federal University of Uberlândia, Brazil 3 Federal University of Pelotas, Brazil 2
Purpose: This study evaluated the bond strength of adhesive luting agents applied to caries-affected dentin (CAD). Methods and materials: Thirty-six non-carious human third molars were abraded to expose an occlusal dentin surface. Caries lesions were induced in half of the samples using a microcosm biofilm model. Biofilm was cultivated under an anaerobic atmosphere for 14 days in a medium enriched with mucin. The same medium containing 1% sucrose was alternated for 4 h per day. Cylinders of resin cement (RelyX ARC, RelyX U200 or BisCem) were built up over the dentin substrate and submitted to shear bond load. The samples were then longitudinally sectioned. The hardness and elastic modulus of dentin was measured at depths of 10, 20, 30, 40, 50, 100, 150 and 200 m from the occlusal surface. A three-dimensional finite element simulation was performed to analyze the residual stress distribution for each experimental condition during the shear bond strength test. Bond strength data were analyzed by two-way ANOVA and hardness and elastic modulus by split-plot ANOVA. Multiple comparisons were performed with the Student–Newman–Keuls test (a = 0.05). Results: Independent of the type of cement, the highest bond strengths were observed in sound dentin. Relyx ARC bond strength was similar to that of RelyX U200 for both substrates; BisCem had the lowest values. CAD had lower hardness values than sound dentin above a depth of 100 m. Elastic modulus exhibited a similar trend, but above a depth of 150 m. Stress distribution during the bond strength test was similar under all experimental conditions. Conclusion: Impairment of the mechanical properties of dentin promoted by carious lesions reduced the bond strength of adhesive luting agents. Keywords: Dental caries; Resin cement; Bond strength http://dx.doi.org/10.1016/j.dental.2014.08.264 264 Tissue engineering: Xeno-free culture of human periodontal ligament stem cells F. Diomede ∗ , O. Trubiani Department of Medical, Oral and Biotechnological Sciences, University “G. D’Annunzio”, Chieti-Pescara, Italy Purpose: The aim of this study was to create a new culture system for the isolation and expansion of stem cells derived from human Periodontal Ligament (hPDLSCs) using a xenofree media to guarantee the stem cells features comprising:
the multiple passage expansion, mesengenic lineage differentiation, cellular phenotype and genomic stability, essential elements for conforming to translation to cell therapy. Methods and materials: hPDLSCs were isolated from horizontal fibers of human periodontal using a minimally invasive surgery. hPDLSCs cultured and expanded in a xeno-free medium showed the morphological features of stem cells, the expression of different markers associated with pluripotency, and a normal karyotype. Under two type of differentiation conditions, osteogenic and adipogenic, hPDLSCs presented mesengenic potential; indeed, a very high accumulation of lipid droplets was evident in the cytoplasm of adipogenic induced cells, and indisputable evidence of osteogenic differentiation, investigated by transmission electron microscopy, and analyzed for gene expression analysis has been shown. Results: Xeno-free culture preserved the immunophenotype and the morphological features as well as the cells grown under FBS (foetal bovine serum)-medium. The proliferation rate and the differentiation into mesegenic lineage of hPDLSCS xeno-free culture was significantly increased, and the cells retained their functionality. Real-Time PCR expression of 92 osteogenesis-associated genes that revealed a significant modulation of 52 transcripts during the xeno-free hPDLSCs osteogenic differentiation. Conclusion: The novel xeno-free method of culture might provide the basis for GMP culture of autologous stem cells, readily accessible from human periodontium, and can be a resource to facilitate their use in human clinical studies for potential therapeutic regeneration. Adult stem cells transplantation into damaged organs has opened new perspectives for the treatment of several human pathologies. The xenofree culture condition can be considered a novel challenge for tissue engineering procedures. http://dx.doi.org/10.1016/j.dental.2014.08.265 265 Effect of bioactive niobium-phosphate-glass incorporated to gutta-percha on biofilm formation C.N. Carvalho 1,3,∗ , Z.J. Wang 2 , Y. Shen 2 , G. Gavini 3 , J.R. Martinelli 4 , A. Manso 2 , M. Haapasalo 2 1
School of Dentistry, University Center of Maranhão-Uniceuma, São Luís, MA, Brazil 2 Department of Oral Biological and Medical Sciences, Faculty of Dentistry, the University of British Columbia, Vancouver, British Columbia, Canada 3 Department of Restorative Dentistry, School of Dentistry, University of São Paulo, São Paulo, Brazil 4 Center of Materials Science and Technology, Energy and Nuclear Research Institute, São Paulo, Brazil Purpose: Gutta-percha is the standard obturating core material in endodontics, but it lacks antimicrobial effect. An ideal endodontic obturation material should inhibit the
d e n t a l m a t e r i a l s 3 0 S ( 2 0 1 4 ) e1–e180
263 Bonding of adhesive luting agents to caries-affected dentin A.C. Peixoto 1 , A.A. Bicalho 2 , C.P. Isolan 3 , T.T. Maske 3 , C.J. Soares 2 , R.R. Moraes 3 , M.S. Cenci 3 , A.L. Faria-E-Silva 1,∗ 1
Federal University of Sergipe, Brazil Federal University of Uberlândia, Brazil 3 Federal University of Pelotas, Brazil 2
Purpose: This study evaluated the bond strength of adhesive luting agents applied to caries-affected dentin (CAD). Methods and materials: Thirty-six non-carious human third molars were abraded to expose an occlusal dentin surface. Caries lesions were induced in half of the samples using a microcosm biofilm model. Biofilm was cultivated under an anaerobic atmosphere for 14 days in a medium enriched with mucin. The same medium containing 1% sucrose was alternated for 4 h per day. Cylinders of resin cement (RelyX ARC, RelyX U200 or BisCem) were built up over the dentin substrate and submitted to shear bond load. The samples were then longitudinally sectioned. The hardness and elastic modulus of dentin was measured at depths of 10, 20, 30, 40, 50, 100, 150 and 200 m from the occlusal surface. A three-dimensional finite element simulation was performed to analyze the residual stress distribution for each experimental condition during the shear bond strength test. Bond strength data were analyzed by two-way ANOVA and hardness and elastic modulus by split-plot ANOVA. Multiple comparisons were performed with the Student–Newman–Keuls test (a = 0.05). Results: Independent of the type of cement, the highest bond strengths were observed in sound dentin. Relyx ARC bond strength was similar to that of RelyX U200 for both substrates; BisCem had the lowest values. CAD had lower hardness values than sound dentin above a depth of 100 m. Elastic modulus exhibited a similar trend, but above a depth of 150 m. Stress distribution during the bond strength test was similar under all experimental conditions. Conclusion: Impairment of the mechanical properties of dentin promoted by carious lesions reduced the bond strength of adhesive luting agents. Keywords: Dental caries; Resin cement; Bond strength http://dx.doi.org/10.1016/j.dental.2014.08.264 264 Tissue engineering: Xeno-free culture of human periodontal ligament stem cells F. Diomede ∗ , O. Trubiani Department of Medical, Oral and Biotechnological Sciences, University “G. D’Annunzio”, Chieti-Pescara, Italy Purpose: The aim of this study was to create a new culture system for the isolation and expansion of stem cells derived from human Periodontal Ligament (hPDLSCs) using a xenofree media to guarantee the stem cells features comprising:
the multiple passage expansion, mesengenic lineage differentiation, cellular phenotype and genomic stability, essential elements for conforming to translation to cell therapy. Methods and materials: hPDLSCs were isolated from horizontal fibers of human periodontal using a minimally invasive surgery. hPDLSCs cultured and expanded in a xeno-free medium showed the morphological features of stem cells, the expression of different markers associated with pluripotency, and a normal karyotype. Under two type of differentiation conditions, osteogenic and adipogenic, hPDLSCs presented mesengenic potential; indeed, a very high accumulation of lipid droplets was evident in the cytoplasm of adipogenic induced cells, and indisputable evidence of osteogenic differentiation, investigated by transmission electron microscopy, and analyzed for gene expression analysis has been shown. Results: Xeno-free culture preserved the immunophenotype and the morphological features as well as the cells grown under FBS (foetal bovine serum)-medium. The proliferation rate and the differentiation into mesegenic lineage of hPDLSCS xeno-free culture was significantly increased, and the cells retained their functionality. Real-Time PCR expression of 92 osteogenesis-associated genes that revealed a significant modulation of 52 transcripts during the xeno-free hPDLSCs osteogenic differentiation. Conclusion: The novel xeno-free method of culture might provide the basis for GMP culture of autologous stem cells, readily accessible from human periodontium, and can be a resource to facilitate their use in human clinical studies for potential therapeutic regeneration. Adult stem cells transplantation into damaged organs has opened new perspectives for the treatment of several human pathologies. The xenofree culture condition can be considered a novel challenge for tissue engineering procedures. http://dx.doi.org/10.1016/j.dental.2014.08.265 265 Effect of bioactive niobium-phosphate-glass incorporated to gutta-percha on biofilm formation C.N. Carvalho 1,3,∗ , Z.J. Wang 2 , Y. Shen 2 , G. Gavini 3 , J.R. Martinelli 4 , A. Manso 2 , M. Haapasalo 2 1
School of Dentistry, University Center of Maranhão-Uniceuma, São Luís, MA, Brazil 2 Department of Oral Biological and Medical Sciences, Faculty of Dentistry, the University of British Columbia, Vancouver, British Columbia, Canada 3 Department of Restorative Dentistry, School of Dentistry, University of São Paulo, São Paulo, Brazil 4 Center of Materials Science and Technology, Energy and Nuclear Research Institute, São Paulo, Brazil Purpose: Gutta-percha is the standard obturating core material in endodontics, but it lacks antimicrobial effect. An ideal endodontic obturation material should inhibit the