- Email: [email protected]
Effect of etching time on MMPs activity and radicular bond-strength
d e n t a l m a t e r i a l s 3 3 S ( 2 0 1 7 ) e1–e92
biomechanical preparation (T1), root canal filling (T2), cleaning cavity (T3), GIC temporary sealing (T4), initial thermocycling (T5), cervical plug (T6), final restoration (T7) and final thermocycling (T8). The data were analyzed using two-way ANOVA and Tukey’s test (˛ = 5%). As a complementary analysis, the teeth were qualitatively evaluated by microcomputed tomography (CT) and confocal laser scanning microscope (CLSM). Results: Changes in color parameters (a and b) were observed in both groups (p < 0.05). After T2, the CAC group (1383 ± 628) presented a significant color change (E) when compared to the CEC group (8.11 ± 4.74) (p < 0.05). In a longitudinal evaluation, the time increased the luminosity (L) mean values. The CT and CLSM qualitative analysis showed the inadequate cut of the gutta-percha cone for CAC group, as well as the presence of endodontic sealer and adhesive system. Also, after the final restoration, it was possible to observe the presence of voids in the CAC, mainly in the vestibular surface (Table 1). Conclusions: The CAC in human anterior teeth may influence the color stability of the dental crown during each step of the endodontic treatment. http://dx.doi.org/10.1016/j.dental.2017.08.103 103 Endogenous enzymatic activity on deciduous and permanent dentin A. Mazzoni 1,∗ , A. Comba 1 , T. Maravic 1 , M. Cadenaro 2 , N. Scotti 3 , L. Breschi 1 1
University of Bologna, DIBINEM, Italy Department of Medical Sciences, University of Trieste, Italy 3 Dental School, University of Turin, Italy 2
Purpose/aim: Endogenous dentin matrix-metalloproteinases (MMPs) are claimed to be responsible for the degradation of resin–dentin interface over time. The hydrolysis leads to loss of bond strength, forming gaps between the resin and the tooth structure. The age of the patient and the kind of dentinal substrate, deciduous or permanent dentin, could influence the amount of enzymatic activity, which could affect the results of the studies on dentin and the longevity of the adhesive interface over time. The aim of the study was to investigate whether there are differences in the age-related activity of dentinal gelatinases using zymographic assay and in situ zymographic assay. Materials and methods: For the zymographic assay analysis, separate pools of dentin powder were obtained from sound teeth of: (1) deciduous teeth and (2) permanent molars. Each pool was divided in two, with 1a and 2a left mineralized (as control), while 1b and 2b demineralized with 10% phosphoric acid. Different pools of dentin powder were submitted to the zymographic analysis. Further, in situ zymographic assay was performed on sections of dentin of the same groups. Results: Deciduous dentin powder groups showed phantom expressions in the area of the bands for MMP-2 and MMP-9. As for the permanent dentin, demineralized groups showed higher gelatinolytic activity with respect to the mineralized ones. The signal of the MMPs was stronger and more
e53
clearly delineated in the permanent dentin as compared to the deciduous one. In situ zymography also displayed distinctive differences in the activity of MMPs in the different groups. Conclusions: The discrepancies in the enzymatic activity detected could be related to the differences in the amount of mineralized tissue of the deciduous teeth; however, additional studies are needed to further investigate MMPs expression in deciduous teeth. http://dx.doi.org/10.1016/j.dental.2017.08.104 104 Effect of etching time on MMPs activity and radicular bond-strength R. Michelotto Tempesta 1,∗ , A. Comba 2 , T. Maravic 2 , A. Mazzoni 2 , N. Scotti 1 , L. Breschi 2 1 2
Dental School, University of Turin, Italy DIBINEM, University of Bologna, Italy
Purpose/aim: The aim of this in vitro study was to evaluate the effect of different etching time with or without the application of ethanol pretreatment of a novel hydrophilic multi-mode universal adhesive (Clearfil Universal Quick, Kuraray) on immediate push-out bond strength and MMPs gelatinolytic activity on radicular dentin. Materials and methods: 48 single root teeth were selected, endodontically treated and obturated. 7 days after obturation, an 8-mm post space was prepared with dedicated drills. Samples were randomly divided into 4 groups according to the adhesive protocol applied: G1 – 15 s H3 PO4 application + Universal Quick; G2 – 60 s H3 PO4 application + Universal Quick; G3 – 15 s H3 PO4 application + Ethanolwet bond + Universal Quick; G4 – 60 s H3 PO4 + Ethanol-wet bond application + Universal Quick. All adhesives were applied following manufacturer’s instructions, and fiber posts were luted into the post space with the same cement (DC Core, Kuraray). Specimens of each group were further cured for 40 s. After 24 h of storage in artificial saliva specimens were prepared to perform micropush-out test and nanoleakage analysis of the coronal and apical region. Additionally, in situ zymographic assay was performed to investigate endogenous MMPs activity within the hybrid layer. Results were statistically analyzed with ANOVA and Tukey’s post-hoc tests. Statistical significance was set for p < 0.05. Results: Three-way ANOVA analysis showed a statistically significant difference in push-out bond strength values for the variable area (p = 0.01) and etching time (p = 0.01), but not for the ethanol pretreatment variable (p = 0.50). In particular, coronal samples showed immediate bond strength significantly higher than the apical samples. Furthermore, when dentin was etched for 60 s, push-out results are significantly higher than 15 s etched teeth. In situ zymography quantification analysis revealed that all tested groups independently from activate MMPs gelatinolytic activity. Conclusions: In radicular dentin, a prolonged etching time seems to improve immediate bond strength, regardless the application of an ethanol pretreatment. However, in situ zymography assay revealed an increased MMPs activation
e54
d e n t a l m a t e r i a l s 3 3 S ( 2 0 1 7 ) e1–e92
when H3 PO4 is applied for 60 s, thus creating the possibility of a faster degradation of the hybrid layer over time. Longer observation times are needed to validate these in vitro results and better clarify the role of extended etching time on radicular dentin. http://dx.doi.org/10.1016/j.dental.2017.08.105 105 Mechanical properties of Y:TZP/TiO2 coated with hydroxyapatite for dental implants R.B.P. Miranda 1,∗ , J. Marchi 2 , V. Ussui 3 , D.R.R. Lazar 3 , W.G.J. Miranda 1 , P.F. Cesar 1
815.4a; T10: 455.7b and T30: 336.0c), E in GPa (control: 213.4a; T10: 155.8b and T30: 134.0c) and relative density in % (control: 99.0a; T10: 94.4c and T30: 96.3b) of the Y:TZP/TiO2 composite. The presence of 30% titania caused substantial increase in m and PR. Biomimetic coating resulted in the formation of apatite globules heterogeneously distributed on the surface of the material and this treatment did not significantly alter the f and m of the composite (Table 1). Conclusions: The Y:TZP/TiO2 composite coated with a layer of CaP has great potential to be used as implant material. Properties of the powder were affected by titania addition. Addition of titania to Y:TZP caused an increase in grain size, a significant decrease in f , E and RD. The presence of biomimetic coating did not jeopardize the reliability of Y:TZP/TiO2 composite.
1
University of São Paulo, Brazil Federal University of ABC, Brazil 3 Nuclear and Energy Research Institute, Brazil
http://dx.doi.org/10.1016/j.dental.2017.08.106
2
106
Purpose/aim: (1) To investigate the effect of titania content in mol% (0, 10 and 30) in the specific surface area (SBET), the size of the agglomerates and the intensity of the peaks corresponding to crystalline phase present in the ceramic powder of Y:TZP/TiO2 ; (2) to investigate the effect of titania addition (0, 10 and 30 mol%) on the microstructure, relative density (RD), Young’s modulus (E), Poisson’s ratio (PR), flexural strength ( f ) and Weibull modulus (m) of a Y:TZP/TiO2 composite; and (3) to investigate the effect of the presence of a biomimetic coating on the microstructure and mechanical properties ( f and m) of Y:TZP/TiO2 composite. Materials and methods: Y:TZP (3 mol% of yttria) and Y:TZP/TiO2 composite (10 or 30 mol% of titania) were synthesized using a co-precipitation route. The powders were pressed and sintered at 1400 ◦ C/2 h. Half of the discs were subjected to biomimetic coating. The powders were characterized by X-ray diffraction (XRD), laser scattering, gas adsorption and scanning electron microscopy (SEM). The surfaces, with and without biomimetic coating, were characterized by SEM and XRD. The RD was measured by the Archimedes’ principle. E and PR were measured by ultrasonic pulse-echo method. For the mechanical properties the specimens (n = 30 for each group) were tested in a universal testing machine. Weibull modulus was estimated by the maximum likelihood method and ANOVA with Tukey test (˛ = 5%) was used to evaluate f , E and RD. Results: All powders had a SBET greater than 42 m2 /g and the titania addition favored the formation of larger agglomerates. Titania addition increased the grain size of the composite and caused a significant decrease in the f in MPa (control:
Antibacterial activity and flexural strength for experimental composites with graphene M. Moldovan 1,∗ , C. Prejmerean 1 , D. Prodan 1 , L. Slilaghi Dumitrescu 1 , R. Carpa 1 , S. Pruneanu 2 , C. Sarosi 1 1
Babes Bolyai University, Cluj-Napoca, Romania National Institute for Research and Development of Isotopic and Molecular Technologies, Cluj-Napoca, Romania
2
Purpose/aim: The aim of this study was to develop composite materials with antibacterial activity using nanopowders of graphene oxide (GO-SiO2 and GO-ZrO2 synthesized in INCDTIM laboratory) in difference concentration. In this study was to evaluate the antibacterial activity, elastic modulus (E) and flexural strength (FS). Materials and methods: Five experimental composites were made with organic matrix of BisGMA (synthesized in our laboratory)/TEGDMA (Aldrich) and inorganic phase: (HA-SiO2 , barium glass, GO-SiO2 : 1%, 0.8% – for GS1, GS2; and HA-Zr, barium glass, GO-ZrO2 : 1%, 0.8% for GZ1, GZ2) and GC (HAZr, HA-SiO2 , colloidal silica; barium glass) composite without graphene, in 20/80 proportions of weight. Specimens for flexural properties (25 mm × 2 mm × 2 mm) were half immediate tested (24 h) and half storage (1 month). Elastic modulus (E) and flexural strength (FS) was measured using the three point bending test (n = 10), in accordance with ISO 4029/2000 (Lloyd Tools- LR5k Plus). The antimicrobial activity materials were evaluated using the agar diffusion method. The bacterial
Table 1 – Mean ± standard deviation (coefficient of variation) of flexural strength ( f ) and Weibull modulus (95% confidence interval) (m). Values followed by the same letter are statistically similar (p > 0.05). Titania content (mol%)
Flexural strength ( f ) (MPa)
Weibull modulus (m)
Biomimetic coating
0 10 30
Biomimetic coating
No
Yes
No
815.4 ± 145.1a (18%) 455.7 ± 48.4b (11%) 336.0 ± 38.7c (11%)
763.6 ± 144.2a (19%) 439.4 ± 65.4b (15%) 334.2 ± 43.6c (13%)
6.4b,c (4.7–8,6) 10.5a,b (7.7–14.1) 11.7a (8.6–15.8)
Yes 5.4c (3.9–7.4) 8.7a,b,c (6.3–11.7) 9.9a,b,c (7.3–13.4)
biomechanical preparation (T1), root canal filling (T2), cleaning cavity (T3), GIC temporary sealing (T4), initial thermocycling (T5), cervical plug (T6), final restoration (T7) and final thermocycling (T8). The data were analyzed using two-way ANOVA and Tukey’s test (˛ = 5%). As a complementary analysis, the teeth were qualitatively evaluated by microcomputed tomography (CT) and confocal laser scanning microscope (CLSM). Results: Changes in color parameters (a and b) were observed in both groups (p < 0.05). After T2, the CAC group (1383 ± 628) presented a significant color change (E) when compared to the CEC group (8.11 ± 4.74) (p < 0.05). In a longitudinal evaluation, the time increased the luminosity (L) mean values. The CT and CLSM qualitative analysis showed the inadequate cut of the gutta-percha cone for CAC group, as well as the presence of endodontic sealer and adhesive system. Also, after the final restoration, it was possible to observe the presence of voids in the CAC, mainly in the vestibular surface (Table 1). Conclusions: The CAC in human anterior teeth may influence the color stability of the dental crown during each step of the endodontic treatment. http://dx.doi.org/10.1016/j.dental.2017.08.103 103 Endogenous enzymatic activity on deciduous and permanent dentin A. Mazzoni 1,∗ , A. Comba 1 , T. Maravic 1 , M. Cadenaro 2 , N. Scotti 3 , L. Breschi 1 1
University of Bologna, DIBINEM, Italy Department of Medical Sciences, University of Trieste, Italy 3 Dental School, University of Turin, Italy 2
Purpose/aim: Endogenous dentin matrix-metalloproteinases (MMPs) are claimed to be responsible for the degradation of resin–dentin interface over time. The hydrolysis leads to loss of bond strength, forming gaps between the resin and the tooth structure. The age of the patient and the kind of dentinal substrate, deciduous or permanent dentin, could influence the amount of enzymatic activity, which could affect the results of the studies on dentin and the longevity of the adhesive interface over time. The aim of the study was to investigate whether there are differences in the age-related activity of dentinal gelatinases using zymographic assay and in situ zymographic assay. Materials and methods: For the zymographic assay analysis, separate pools of dentin powder were obtained from sound teeth of: (1) deciduous teeth and (2) permanent molars. Each pool was divided in two, with 1a and 2a left mineralized (as control), while 1b and 2b demineralized with 10% phosphoric acid. Different pools of dentin powder were submitted to the zymographic analysis. Further, in situ zymographic assay was performed on sections of dentin of the same groups. Results: Deciduous dentin powder groups showed phantom expressions in the area of the bands for MMP-2 and MMP-9. As for the permanent dentin, demineralized groups showed higher gelatinolytic activity with respect to the mineralized ones. The signal of the MMPs was stronger and more
e53
clearly delineated in the permanent dentin as compared to the deciduous one. In situ zymography also displayed distinctive differences in the activity of MMPs in the different groups. Conclusions: The discrepancies in the enzymatic activity detected could be related to the differences in the amount of mineralized tissue of the deciduous teeth; however, additional studies are needed to further investigate MMPs expression in deciduous teeth. http://dx.doi.org/10.1016/j.dental.2017.08.104 104 Effect of etching time on MMPs activity and radicular bond-strength R. Michelotto Tempesta 1,∗ , A. Comba 2 , T. Maravic 2 , A. Mazzoni 2 , N. Scotti 1 , L. Breschi 2 1 2
Dental School, University of Turin, Italy DIBINEM, University of Bologna, Italy
Purpose/aim: The aim of this in vitro study was to evaluate the effect of different etching time with or without the application of ethanol pretreatment of a novel hydrophilic multi-mode universal adhesive (Clearfil Universal Quick, Kuraray) on immediate push-out bond strength and MMPs gelatinolytic activity on radicular dentin. Materials and methods: 48 single root teeth were selected, endodontically treated and obturated. 7 days after obturation, an 8-mm post space was prepared with dedicated drills. Samples were randomly divided into 4 groups according to the adhesive protocol applied: G1 – 15 s H3 PO4 application + Universal Quick; G2 – 60 s H3 PO4 application + Universal Quick; G3 – 15 s H3 PO4 application + Ethanolwet bond + Universal Quick; G4 – 60 s H3 PO4 + Ethanol-wet bond application + Universal Quick. All adhesives were applied following manufacturer’s instructions, and fiber posts were luted into the post space with the same cement (DC Core, Kuraray). Specimens of each group were further cured for 40 s. After 24 h of storage in artificial saliva specimens were prepared to perform micropush-out test and nanoleakage analysis of the coronal and apical region. Additionally, in situ zymographic assay was performed to investigate endogenous MMPs activity within the hybrid layer. Results were statistically analyzed with ANOVA and Tukey’s post-hoc tests. Statistical significance was set for p < 0.05. Results: Three-way ANOVA analysis showed a statistically significant difference in push-out bond strength values for the variable area (p = 0.01) and etching time (p = 0.01), but not for the ethanol pretreatment variable (p = 0.50). In particular, coronal samples showed immediate bond strength significantly higher than the apical samples. Furthermore, when dentin was etched for 60 s, push-out results are significantly higher than 15 s etched teeth. In situ zymography quantification analysis revealed that all tested groups independently from activate MMPs gelatinolytic activity. Conclusions: In radicular dentin, a prolonged etching time seems to improve immediate bond strength, regardless the application of an ethanol pretreatment. However, in situ zymography assay revealed an increased MMPs activation
e54
d e n t a l m a t e r i a l s 3 3 S ( 2 0 1 7 ) e1–e92
when H3 PO4 is applied for 60 s, thus creating the possibility of a faster degradation of the hybrid layer over time. Longer observation times are needed to validate these in vitro results and better clarify the role of extended etching time on radicular dentin. http://dx.doi.org/10.1016/j.dental.2017.08.105 105 Mechanical properties of Y:TZP/TiO2 coated with hydroxyapatite for dental implants R.B.P. Miranda 1,∗ , J. Marchi 2 , V. Ussui 3 , D.R.R. Lazar 3 , W.G.J. Miranda 1 , P.F. Cesar 1
815.4a; T10: 455.7b and T30: 336.0c), E in GPa (control: 213.4a; T10: 155.8b and T30: 134.0c) and relative density in % (control: 99.0a; T10: 94.4c and T30: 96.3b) of the Y:TZP/TiO2 composite. The presence of 30% titania caused substantial increase in m and PR. Biomimetic coating resulted in the formation of apatite globules heterogeneously distributed on the surface of the material and this treatment did not significantly alter the f and m of the composite (Table 1). Conclusions: The Y:TZP/TiO2 composite coated with a layer of CaP has great potential to be used as implant material. Properties of the powder were affected by titania addition. Addition of titania to Y:TZP caused an increase in grain size, a significant decrease in f , E and RD. The presence of biomimetic coating did not jeopardize the reliability of Y:TZP/TiO2 composite.
1
University of São Paulo, Brazil Federal University of ABC, Brazil 3 Nuclear and Energy Research Institute, Brazil
http://dx.doi.org/10.1016/j.dental.2017.08.106
2
106
Purpose/aim: (1) To investigate the effect of titania content in mol% (0, 10 and 30) in the specific surface area (SBET), the size of the agglomerates and the intensity of the peaks corresponding to crystalline phase present in the ceramic powder of Y:TZP/TiO2 ; (2) to investigate the effect of titania addition (0, 10 and 30 mol%) on the microstructure, relative density (RD), Young’s modulus (E), Poisson’s ratio (PR), flexural strength ( f ) and Weibull modulus (m) of a Y:TZP/TiO2 composite; and (3) to investigate the effect of the presence of a biomimetic coating on the microstructure and mechanical properties ( f and m) of Y:TZP/TiO2 composite. Materials and methods: Y:TZP (3 mol% of yttria) and Y:TZP/TiO2 composite (10 or 30 mol% of titania) were synthesized using a co-precipitation route. The powders were pressed and sintered at 1400 ◦ C/2 h. Half of the discs were subjected to biomimetic coating. The powders were characterized by X-ray diffraction (XRD), laser scattering, gas adsorption and scanning electron microscopy (SEM). The surfaces, with and without biomimetic coating, were characterized by SEM and XRD. The RD was measured by the Archimedes’ principle. E and PR were measured by ultrasonic pulse-echo method. For the mechanical properties the specimens (n = 30 for each group) were tested in a universal testing machine. Weibull modulus was estimated by the maximum likelihood method and ANOVA with Tukey test (˛ = 5%) was used to evaluate f , E and RD. Results: All powders had a SBET greater than 42 m2 /g and the titania addition favored the formation of larger agglomerates. Titania addition increased the grain size of the composite and caused a significant decrease in the f in MPa (control:
Antibacterial activity and flexural strength for experimental composites with graphene M. Moldovan 1,∗ , C. Prejmerean 1 , D. Prodan 1 , L. Slilaghi Dumitrescu 1 , R. Carpa 1 , S. Pruneanu 2 , C. Sarosi 1 1
Babes Bolyai University, Cluj-Napoca, Romania National Institute for Research and Development of Isotopic and Molecular Technologies, Cluj-Napoca, Romania
2
Purpose/aim: The aim of this study was to develop composite materials with antibacterial activity using nanopowders of graphene oxide (GO-SiO2 and GO-ZrO2 synthesized in INCDTIM laboratory) in difference concentration. In this study was to evaluate the antibacterial activity, elastic modulus (E) and flexural strength (FS). Materials and methods: Five experimental composites were made with organic matrix of BisGMA (synthesized in our laboratory)/TEGDMA (Aldrich) and inorganic phase: (HA-SiO2 , barium glass, GO-SiO2 : 1%, 0.8% – for GS1, GS2; and HA-Zr, barium glass, GO-ZrO2 : 1%, 0.8% for GZ1, GZ2) and GC (HAZr, HA-SiO2 , colloidal silica; barium glass) composite without graphene, in 20/80 proportions of weight. Specimens for flexural properties (25 mm × 2 mm × 2 mm) were half immediate tested (24 h) and half storage (1 month). Elastic modulus (E) and flexural strength (FS) was measured using the three point bending test (n = 10), in accordance with ISO 4029/2000 (Lloyd Tools- LR5k Plus). The antimicrobial activity materials were evaluated using the agar diffusion method. The bacterial
Table 1 – Mean ± standard deviation (coefficient of variation) of flexural strength ( f ) and Weibull modulus (95% confidence interval) (m). Values followed by the same letter are statistically similar (p > 0.05). Titania content (mol%)
Flexural strength ( f ) (MPa)
Weibull modulus (m)
Biomimetic coating
0 10 30
Biomimetic coating
No
Yes
No
815.4 ± 145.1a (18%) 455.7 ± 48.4b (11%) 336.0 ± 38.7c (11%)
763.6 ± 144.2a (19%) 439.4 ± 65.4b (15%) 334.2 ± 43.6c (13%)
6.4b,c (4.7–8,6) 10.5a,b (7.7–14.1) 11.7a (8.6–15.8)
Yes 5.4c (3.9–7.4) 8.7a,b,c (6.3–11.7) 9.9a,b,c (7.3–13.4)