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Staining solutions and bleaching agents: Enamel microhardness and roughness effects
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d e n t a l m a t e r i a l s 3 3 S ( 2 0 1 7 ) e1–e92
28 Mechanical properties of dental enamel after hybridization using electrokinetic flow H.L. Carlo 1,∗ , G.A. Gadelha 2 , M.F.L. Moura 2 , F.G. Carvalho 1 , F.B. Sousa 2 1 2
Federal University of Juiz De Fora, Brazil Federal University of Paraíba, Brazil
Purpose/aim: The electrokinetic (EK) flow was used to hybridize enamel pores through electric voltage. However, the mechanical behavior of the tissue has not yet been analyzed. Materials and methods: Icon dental resin (DGM, Hamburg, Germany) was infiltrated into enamel of extracted human teeth via EK flow and the microhardness and ultimate tensile strength of the tissue were evaluated. Thirty third molars were collected. For the Vickers microhardness test ten teeth were sectioned longitudinally to obtain two hemicrows. These were divided into two groups (n = 10): Infiltrate Group (MH-IG) and Non-Infiltrate Group (MH-NIG). Microhardness was performed at different depths (50, 100, 200, 250 and 500 m). For ultimate tensile strength, twenty teeth were used and divided into two groups: Infiltrated Group (UTS-IG) and Non-Infiltrated Group (UTS-NIG). Each group was divided into two subgroups (n = 10), according to the arrangement of the enamel prisms (parallel or perpendicular). Results: The microhardness data was submitted to paired t-test. MH-IG presented higher values when compared to MH-NIG, regardless of depth. The analysis of the cohesive resistance was due to the correlation between the data obtained from UTS-IG and UTS-NIG specimens. A strong correlation was obtained, indicating that the EK flow did not alter the cohesive resistance of the tissue. Conclusions: It was observed that the infiltration of resin into the enamel via EK flow was effective and increased the microhardness of the tissue without, however, interfering in the cohesive resistance, regardless of the orientation of the prisms.
day of treatment); low carbamide peroxide (Opalescence PF 10%/Ultradent) concentration for 60 min daily during 15days; control, with no bleaching agent applied. The enamel blocks were immersed in different staining solutions (coffee or colabased soda) or not (control) daily for 30 min during 15 days, in order to obtain a factorial scheme of the dental bleaching treatment and staining solution of 3 × 3 (n = 7). Roughness evaluations were performed using a roughness meter with static load of 5 N and speed of 0.25 mm/s, microhardness tests were also performed using a Knoop microhardness indenter, with static load of 25 g/s, assessed before and after treatment associated to the staining solutions. Tukey–Kramer test was performed for statistical evaluations, with a significance level of 5%. Results: There were no significant differences of roughness values among the groups (p = 0.3218) at baseline, colabased soda roughness values were higher (p < 0.0001) than other groups after treatments, but no significant differences were observed between the coffee solution and the control. There were no differences in microhardness values among treatments (p = 0.3368) at baseline. Roughness values for cola-based soda solution were significantly lower than coffee and control groups (p < 0.0001) after treatments. Cola-based soda group showed significant decrease of microhardness values regardless of the bleaching agents used (p < 0.0001). Conclusions: It was concluded that cola-based soda solution decreased enamel microhardness surface and increased its roughness, regardless of bleaching agents used. http://dx.doi.org/10.1016/j.dental.2017.08.030 30 Flexural strength of CAD/CAM and pressed novel lithium disilicate M. Carrabba 1,∗ , Y. Nagasawa 2 , J. Julosky 3 , M. Ferrari 1 1
http://dx.doi.org/10.1016/j.dental.2017.08.029 29 Staining solutions and bleaching agents: Enamel microhardness and roughness effects N.R. Carlos ∗ , F.L.B. Amaral, F.M.G. Franc¸a, C.P. Turssi, R.T. Basting São Leopoldo Mandic Dental School and Research Center, Brazil Purpose/aim: The aim of this study was to evaluate the in situ effects of staining solutions during dental bleaching with high or low peroxides concentrations on microhardness and roughness on enamel surface. Materials and methods: Seven volunteers participated using an intraoral appliance, with nine bovine enamel blocks, during 15 days. The enamel blocks were randomly assigned among different groups according to the treatments: high hydrogen peroxide (OpalescenceBoost PF 40%/Ultradent) concentration for 40 min in 3 sessions (1st, 8th and 15th
University of Siena, Department of Medical Biotechnologies, Siena, Italy 2 Meikai University, School of Dentistry, Sakado, Saitama, Japan 3 Clinic for Paediatric and Preventive Dentistry, School of Dental Medicine, University of Belgrade, Serbia
Purpose/aim: To compare flexural strength of CAD-CAM and heat-pressed lithium disilicates. Materials and methods: For pressed specimens, acrylate polymer blocks were cut with a saw in bars shape. Sprueing, investing and preheating procedures were carried out following manufacturer’s instructions. IPS e.max Press (Ivoclar-Vivadent) and Initial LiSi Press (GC) ingots were pressed following manufacturer’s instructions. For CAD-CAM specimens, blocks of IPS e.max CAD (Ivoclar-Vivadent) and Initial LiSi Block 096Y (GC) were directly cut with slow speed diamond saw in bars shape. Final crystallization was performed following manufacturer’s instructions. Both Press and CAD specimens were polished and finished with silica carbide papers of increasing grit. Final dimensions of the specimens
d e n t a l m a t e r i a l s 3 3 S ( 2 0 1 7 ) e1–e92
28 Mechanical properties of dental enamel after hybridization using electrokinetic flow H.L. Carlo 1,∗ , G.A. Gadelha 2 , M.F.L. Moura 2 , F.G. Carvalho 1 , F.B. Sousa 2 1 2
Federal University of Juiz De Fora, Brazil Federal University of Paraíba, Brazil
Purpose/aim: The electrokinetic (EK) flow was used to hybridize enamel pores through electric voltage. However, the mechanical behavior of the tissue has not yet been analyzed. Materials and methods: Icon dental resin (DGM, Hamburg, Germany) was infiltrated into enamel of extracted human teeth via EK flow and the microhardness and ultimate tensile strength of the tissue were evaluated. Thirty third molars were collected. For the Vickers microhardness test ten teeth were sectioned longitudinally to obtain two hemicrows. These were divided into two groups (n = 10): Infiltrate Group (MH-IG) and Non-Infiltrate Group (MH-NIG). Microhardness was performed at different depths (50, 100, 200, 250 and 500 m). For ultimate tensile strength, twenty teeth were used and divided into two groups: Infiltrated Group (UTS-IG) and Non-Infiltrated Group (UTS-NIG). Each group was divided into two subgroups (n = 10), according to the arrangement of the enamel prisms (parallel or perpendicular). Results: The microhardness data was submitted to paired t-test. MH-IG presented higher values when compared to MH-NIG, regardless of depth. The analysis of the cohesive resistance was due to the correlation between the data obtained from UTS-IG and UTS-NIG specimens. A strong correlation was obtained, indicating that the EK flow did not alter the cohesive resistance of the tissue. Conclusions: It was observed that the infiltration of resin into the enamel via EK flow was effective and increased the microhardness of the tissue without, however, interfering in the cohesive resistance, regardless of the orientation of the prisms.
day of treatment); low carbamide peroxide (Opalescence PF 10%/Ultradent) concentration for 60 min daily during 15days; control, with no bleaching agent applied. The enamel blocks were immersed in different staining solutions (coffee or colabased soda) or not (control) daily for 30 min during 15 days, in order to obtain a factorial scheme of the dental bleaching treatment and staining solution of 3 × 3 (n = 7). Roughness evaluations were performed using a roughness meter with static load of 5 N and speed of 0.25 mm/s, microhardness tests were also performed using a Knoop microhardness indenter, with static load of 25 g/s, assessed before and after treatment associated to the staining solutions. Tukey–Kramer test was performed for statistical evaluations, with a significance level of 5%. Results: There were no significant differences of roughness values among the groups (p = 0.3218) at baseline, colabased soda roughness values were higher (p < 0.0001) than other groups after treatments, but no significant differences were observed between the coffee solution and the control. There were no differences in microhardness values among treatments (p = 0.3368) at baseline. Roughness values for cola-based soda solution were significantly lower than coffee and control groups (p < 0.0001) after treatments. Cola-based soda group showed significant decrease of microhardness values regardless of the bleaching agents used (p < 0.0001). Conclusions: It was concluded that cola-based soda solution decreased enamel microhardness surface and increased its roughness, regardless of bleaching agents used. http://dx.doi.org/10.1016/j.dental.2017.08.030 30 Flexural strength of CAD/CAM and pressed novel lithium disilicate M. Carrabba 1,∗ , Y. Nagasawa 2 , J. Julosky 3 , M. Ferrari 1 1
http://dx.doi.org/10.1016/j.dental.2017.08.029 29 Staining solutions and bleaching agents: Enamel microhardness and roughness effects N.R. Carlos ∗ , F.L.B. Amaral, F.M.G. Franc¸a, C.P. Turssi, R.T. Basting São Leopoldo Mandic Dental School and Research Center, Brazil Purpose/aim: The aim of this study was to evaluate the in situ effects of staining solutions during dental bleaching with high or low peroxides concentrations on microhardness and roughness on enamel surface. Materials and methods: Seven volunteers participated using an intraoral appliance, with nine bovine enamel blocks, during 15 days. The enamel blocks were randomly assigned among different groups according to the treatments: high hydrogen peroxide (OpalescenceBoost PF 40%/Ultradent) concentration for 40 min in 3 sessions (1st, 8th and 15th
University of Siena, Department of Medical Biotechnologies, Siena, Italy 2 Meikai University, School of Dentistry, Sakado, Saitama, Japan 3 Clinic for Paediatric and Preventive Dentistry, School of Dental Medicine, University of Belgrade, Serbia
Purpose/aim: To compare flexural strength of CAD-CAM and heat-pressed lithium disilicates. Materials and methods: For pressed specimens, acrylate polymer blocks were cut with a saw in bars shape. Sprueing, investing and preheating procedures were carried out following manufacturer’s instructions. IPS e.max Press (Ivoclar-Vivadent) and Initial LiSi Press (GC) ingots were pressed following manufacturer’s instructions. For CAD-CAM specimens, blocks of IPS e.max CAD (Ivoclar-Vivadent) and Initial LiSi Block 096Y (GC) were directly cut with slow speed diamond saw in bars shape. Final crystallization was performed following manufacturer’s instructions. Both Press and CAD specimens were polished and finished with silica carbide papers of increasing grit. Final dimensions of the specimens