- Email: [email protected]
TEGDMA effect on reactive oxygen species-related gene expression on pulp cell
e20
d e n t a l m a t e r i a l s 2 8 S ( 2 0 1 2 ) e1–e70
42 Microsilver loaded adhesives: Antimicrobial activity and microtensile bond strength
Conclusions: Within the limits of this study microsilver loaded dentin adhesives showed in vitro antibacterial activity with no significant changes in microtensile bond strength.
J. Zorzin 1,∗ , R. Bürgers 2 , M. Rosentritt 2 , T. Bechert 3 , P. Steinrücke 3 , T. Konradt 4 , A. Petschelt 1 , R. Frankeberger 5
http://dx.doi.org/10.1016/j.dental.2012.07.049 43 Cytotoxicity of in-office bleaching and cell morphology analysis
1
University of Erlangen, Germany University of Regensburg, Germany 3 Bio-Gate AG, Nuremberg, Germany 4 QualityLabs BT GmbH, Nuremberg, Germany 5 University of Marburg, Germany 2
L.C.A.G. Almeida 1,∗ , A.L.F. Briso 1 , C.A.S. Costa 2 , D.G. Soares 2 , E.C.V. Pontes 2 , P.H. Dos Santos 1
Objectives: Secondary caries is the main reason for failure of posterior composite restorations (Demarco et al. Dental Materials 2012;28:87). The purpose of this study was to evaluate the in vitro antimicrobial activity and microtensile bond strength (MTBS) of microsilver loaded dentin adhesives. Materials and methods: Two dentin adhesives (Scotchbond 1 XT, 3M ESPE, Seefeld and Futurabond M, Voco, Cuxhaven, Germany) were loaded with 0.1% and 0.5%wt microsilver (Ag, Microsilver BG, Biogate, Nuremberg, Germany). Unloaded adhesive served as control. For each group occlusal dentin of 4 extracted human molars was exposed and restored with a block of resin composite, bonded according to manufacturer’s instructions, stored in Aqua dest (24 h at 37 ◦ C), sectioned into bar-shaped specimens (0.7 mm × 0.7 mm) and submitted to MTBS testing at a crosshead speed of 1 mm/min. MTBS was analyzed using one-way ANOVA (mod SNK, ˛ = 0.05). To assess antimicrobial activity a proliferation test was used (Bechert et al. Nature Medicine 2000;6:1053). Specimens of each group (2 mm × 27 mm, n = 32) were incubated with log-phase microorganisms (Staphylococcus epidermidis DSM 18857, Pseudomonas aeruginosa DSM 939, 105 cells/ml). Loosely attached cells were removed by sequential washing. The specimens were rinsed with PBS and inserted into a microplate with minimal medium for incubation (18 h at 37 ◦ C). After removing the specimens, the growth of released daughter cells into the minimal medium was stimulated by addition of trypticase soy broth. Proliferation of microbes was followed by optical density measurements. The time span for the microsilver loaded specimen’s medium to reach the same optical density as the control group medium was measured (Net-Onset-Time). If this time was more than 5 h it was determined that at least 99.9% initially adhering to the specimen were killed. Results: Material
%wt Ag
MTBS (MPa)
Net-Onset-Time (h)
0 0.1 0.5 0 0.1 0.5
27.24 (A) 25.02 (A) 26.80 (A) 20.25 (a) 17.76 (a) 17.97 (a)
2
Paulista State University, UNESP, Arac¸atuba, São Paulo, Brazil Paulista State University, UNESP, Araraquara, São Paulo, Brazil
Objectives: To evaluate the trans-enamel and transdentinal cytotoxicity and the effects in cell morphology caused by in-office bleaching protocols in cultured MDPC-23 odontoblast-like cells. Materials and methods: Bovine enamel/dentin discs were individually adapted to artificial pulp chambers. The following groups were evaluated: G1 – control group (no treatment); G2, G3 and G4 – 3 applications of a 35% H2 O2 gel for 15 min. 1, 2 or 3 sessions respectively; G5, G6 and G7 – 1 application of a 35% H2 O2 gel for 45 min. 1,2 or 3 sessions respectively; G8, G9 and G10 – 1 application of a 20% H2 O2 gel for 50 min. 1, 2 or 3 sessions respectively. Cell metabolism (MTT assay) (n = 11) and cell morphology (SEM) (n = 3) were evaluated after application of the extracts (culture medium plus bleaching gel components that diffused through the enamel/dentin discs) for 60 min on previously MDPC-23 cultured cells and the data was submitted to statistical analysis (ANOVA/Tukey; a = 0.05). Results: Considering G1 (control group) as 100% of cell metabolism, statistical difference was observed in all bleached groups, with significant reduction of cell metabolism (from 26.48% to 38.27%), but without statistical difference between experimental groups. Alteration on cell morphology was observed for all experimental groups; it was observed intense cellular contraction and cytoplasm deformation. Conclusions: Bleaching protocols tested caused significant trans-enamel and trans-dentinal cytotoxicity to the MDPC-23 cell cultures. http://dx.doi.org/10.1016/j.dental.2012.07.050 44 TEGDMA effect on reactive oxygen species-related gene expression on pulp cell W.J. Chang ∗ , S.G. Cho, S.Y. Kim
S. epidermidis P. aeruginosa Scotchbond 1 XT Scotchbond 1 XT Scotchbond 1 XT Futurabond M Futurabond M Futurabond M
1
0 19.1 32.9 0 23.8 36.6
Letters in parentheses indicate homogeneous subsets.
0 >48 >48 0 25.7 9.9
Kyung Hee University, South Korea Objectives: To investigate the change of early time-series gene expression in human dental pulp cell (HDPC) related to reactive oxygen species (ROS) after the treatment of TEGDMA in its minimal toxic concentration. Materials and methods: HDPCs were obtained from human premolars and were cultured in DMEM under 37 ◦ C until cellular senescence occurred in passage 7. The cytotoxicity caused by TEGDMA to HDPC was estimated using the MTT assay. Minimal toxic concentration (mTc) that HDPC 90% survive was
d e n t a l m a t e r i a l s 2 8 S ( 2 0 1 2 ) e1–e70
determined using dose–response curve. Representative six genes associated with cellular response to ROS were selected for qRT-PCR analysis. qRT-PCR was performed 6 hr, 12 hr, 24 hr and 48 hr after TEGDMA treatment in triplicate. Results: Time-series gene expression change after TEGDMA treatment Gene
6 hr/ control
12 hr/ control
24 hr/ control
48 hr/ control
HMOX1 SOD2 COL1A1 STAT1 DDIT3 SERPINE1
35.83 −1.95 −1.28 −1.41 3.59 4.41
37.45 −2.53 −1.64 −1.53 1.92 2.76
13.62 −3.05 −1.99 −1.28 1.70 2.07
2.10 −6.99 −8.20 −4.52 1.57 3.70
e21
Conclusions: When HDPCs was treated with minimal toxic concentration of TEGDMA, gene expression related to mineralization of pulp cell showed the tendency to be suppressed. http://dx.doi.org/10.1016/j.dental.2012.07.052 46 Delayed crack behavior of veneered Ce-TZP/Al2 O3 discs: The mystery continues A.A. Barrett ∗ , J.J. Mecholsky Jr., K.J. Anusavice
Each value means fold changes of gene expression compared to the control group Conclusions: When HDPC was treated with mTc of TEGDMA, genetic response to ROS occurred relatively early and was followed by the expression change of the genes that regulate cell response to ROS. http://dx.doi.org/10.1016/j.dental.2012.07.051 45 Effect of TEGDMA on mineralization related-gene expression of pulp cell J.H. Lee ∗ , J.W. Lee, S.Y. Kim Kyung Hee University, South Korea Objectives: To investigate early time-series gene expression change related to mineralization of pulp cell after treatment with minimal toxic concentration of TEGDMA. Materials and methods: Human dental pulp cells (HDPCs) were obtained from human premolar. Coronal part was collected and cultured in DMEM under 37 ◦ C until cellular senescence occurred in passage 7. The cytotoxicity caused by TEGDMA to HDPCs was estimated using the MTT Assay. Minimal toxic concentration that 90% of HDPCs survive was determined using dose–response curve. Representative six genes associated with the mineralization were selected for qRT-PCR analysis. The PCR analyses were performed in triplicate for 6 hr, 12 hr, 24 hr, 48 hr after TEGDMA treatment. Results: Time-series gene expression change after TEGDMA treatment Gene
6 hr/ control
12 hr/ control
24 hr/ control
48 hr/ contol
BMP4 JUND SMAD3 COL1A1 BMP6 SPP1
−5.07 −1.80 −1.72 −1.28 1.76 1.87
−4.71 −2.14 −2.11 −1.64 1.41 2.80
−3.76 −1.53 −1.29 −1.99 1.36 6.18
−5.11 −1.34 −1.77 −8.20 2.35 8.58
Each value means fold change of gene expression compared to the control group.
University of Florida College of Dentistry, Gainesville, FL, USA Objectives: Determine the effect of veneer/core ratios on delayed crack formation in a dental veneer bonded to a CeTZP/Al2 O3 core. Materials and methods: Three veneer (v)/core (c) ratios were prepared: 2:1 (0.8v /0.4c mm); 1:1 (0.6v /0.6c mm); 1:2 (0.4v /0.8c mm). Ce-TZP/Al2 O3 discs (Matsushita Ltd., JP) were: abraded (600 grit); blasted (50 m Al2 O3 , 15 s at 10 mm); ‘regenerated’ (15 min at 1000 ◦ C). Ceramic liner was fired (930 ◦ C) onto zirconia discs (12 mm dia), veneered (920 ◦ C) (Shofu Vintage ZRTM System), and finished (15 m diamond). The ceramic (1.2 mm thick) discs (n = 45) were cemented (Panavia F2, Kuraray) onto epoxy-resin substrates (3.6 mm thick). Specimens were aged (DI H2 O at 37 ◦ C) and examined visually and microscopically with fiberoptic illumination after 1 year storage. Veneers underwent microstructural (SEM and EDS) and fractographic analysis; and, the core TEM quantitation (Cliff Lorimer method). Results: After 1 year aqueous storage, no external load applied, unexpected failures included visibly cracked veneers (29%) and partial delaminations. The post immersion fractures for v/c ratios were: 1:1 – 40%; 1:2 – 33%; 2:1 – 13%. Elastic constants were: core: E = 221 GPa, = 29, = 5.28 g/cm3 ; Veneer: E = 77 GPa, = 22, = 2.4 g/cm3 . TEM elemental line scan of the core ceramic indicated a consistent surface composition (atomic wt.%): 7.0% Ce (La1); 55.7% Zr (Ka1); 7.7% Al (Ka1); 29.7% O (Ka1). However, SEM/EDS of the veneers depicted inhomogeneous regions with clusters of zirconia particles (≤2.1 m) distributed within the glassy matrix. Multiscan digital microscopy (VHX Keyence, JP) revealed a tortuous surface with multi-directional fracture markings indicative of residual tensile stress around the particles. Conclusions: The primary cause of veneer cracking in the bilayer discs does not appear to be related to veneer/core ratio. These results suggest that the effects of cooling rate and viscoelastic behaviour need to be investigated. Further research continues, including fractography, in order to determine the causative source of the extreme residual tensile stresses that led to pre-mature veneer fractures. NIH/NIDCR Grant DE06672. http://dx.doi.org/10.1016/j.dental.2012.07.053
d e n t a l m a t e r i a l s 2 8 S ( 2 0 1 2 ) e1–e70
42 Microsilver loaded adhesives: Antimicrobial activity and microtensile bond strength
Conclusions: Within the limits of this study microsilver loaded dentin adhesives showed in vitro antibacterial activity with no significant changes in microtensile bond strength.
J. Zorzin 1,∗ , R. Bürgers 2 , M. Rosentritt 2 , T. Bechert 3 , P. Steinrücke 3 , T. Konradt 4 , A. Petschelt 1 , R. Frankeberger 5
http://dx.doi.org/10.1016/j.dental.2012.07.049 43 Cytotoxicity of in-office bleaching and cell morphology analysis
1
University of Erlangen, Germany University of Regensburg, Germany 3 Bio-Gate AG, Nuremberg, Germany 4 QualityLabs BT GmbH, Nuremberg, Germany 5 University of Marburg, Germany 2
L.C.A.G. Almeida 1,∗ , A.L.F. Briso 1 , C.A.S. Costa 2 , D.G. Soares 2 , E.C.V. Pontes 2 , P.H. Dos Santos 1
Objectives: Secondary caries is the main reason for failure of posterior composite restorations (Demarco et al. Dental Materials 2012;28:87). The purpose of this study was to evaluate the in vitro antimicrobial activity and microtensile bond strength (MTBS) of microsilver loaded dentin adhesives. Materials and methods: Two dentin adhesives (Scotchbond 1 XT, 3M ESPE, Seefeld and Futurabond M, Voco, Cuxhaven, Germany) were loaded with 0.1% and 0.5%wt microsilver (Ag, Microsilver BG, Biogate, Nuremberg, Germany). Unloaded adhesive served as control. For each group occlusal dentin of 4 extracted human molars was exposed and restored with a block of resin composite, bonded according to manufacturer’s instructions, stored in Aqua dest (24 h at 37 ◦ C), sectioned into bar-shaped specimens (0.7 mm × 0.7 mm) and submitted to MTBS testing at a crosshead speed of 1 mm/min. MTBS was analyzed using one-way ANOVA (mod SNK, ˛ = 0.05). To assess antimicrobial activity a proliferation test was used (Bechert et al. Nature Medicine 2000;6:1053). Specimens of each group (2 mm × 27 mm, n = 32) were incubated with log-phase microorganisms (Staphylococcus epidermidis DSM 18857, Pseudomonas aeruginosa DSM 939, 105 cells/ml). Loosely attached cells were removed by sequential washing. The specimens were rinsed with PBS and inserted into a microplate with minimal medium for incubation (18 h at 37 ◦ C). After removing the specimens, the growth of released daughter cells into the minimal medium was stimulated by addition of trypticase soy broth. Proliferation of microbes was followed by optical density measurements. The time span for the microsilver loaded specimen’s medium to reach the same optical density as the control group medium was measured (Net-Onset-Time). If this time was more than 5 h it was determined that at least 99.9% initially adhering to the specimen were killed. Results: Material
%wt Ag
MTBS (MPa)
Net-Onset-Time (h)
0 0.1 0.5 0 0.1 0.5
27.24 (A) 25.02 (A) 26.80 (A) 20.25 (a) 17.76 (a) 17.97 (a)
2
Paulista State University, UNESP, Arac¸atuba, São Paulo, Brazil Paulista State University, UNESP, Araraquara, São Paulo, Brazil
Objectives: To evaluate the trans-enamel and transdentinal cytotoxicity and the effects in cell morphology caused by in-office bleaching protocols in cultured MDPC-23 odontoblast-like cells. Materials and methods: Bovine enamel/dentin discs were individually adapted to artificial pulp chambers. The following groups were evaluated: G1 – control group (no treatment); G2, G3 and G4 – 3 applications of a 35% H2 O2 gel for 15 min. 1, 2 or 3 sessions respectively; G5, G6 and G7 – 1 application of a 35% H2 O2 gel for 45 min. 1,2 or 3 sessions respectively; G8, G9 and G10 – 1 application of a 20% H2 O2 gel for 50 min. 1, 2 or 3 sessions respectively. Cell metabolism (MTT assay) (n = 11) and cell morphology (SEM) (n = 3) were evaluated after application of the extracts (culture medium plus bleaching gel components that diffused through the enamel/dentin discs) for 60 min on previously MDPC-23 cultured cells and the data was submitted to statistical analysis (ANOVA/Tukey; a = 0.05). Results: Considering G1 (control group) as 100% of cell metabolism, statistical difference was observed in all bleached groups, with significant reduction of cell metabolism (from 26.48% to 38.27%), but without statistical difference between experimental groups. Alteration on cell morphology was observed for all experimental groups; it was observed intense cellular contraction and cytoplasm deformation. Conclusions: Bleaching protocols tested caused significant trans-enamel and trans-dentinal cytotoxicity to the MDPC-23 cell cultures. http://dx.doi.org/10.1016/j.dental.2012.07.050 44 TEGDMA effect on reactive oxygen species-related gene expression on pulp cell W.J. Chang ∗ , S.G. Cho, S.Y. Kim
S. epidermidis P. aeruginosa Scotchbond 1 XT Scotchbond 1 XT Scotchbond 1 XT Futurabond M Futurabond M Futurabond M
1
0 19.1 32.9 0 23.8 36.6
Letters in parentheses indicate homogeneous subsets.
0 >48 >48 0 25.7 9.9
Kyung Hee University, South Korea Objectives: To investigate the change of early time-series gene expression in human dental pulp cell (HDPC) related to reactive oxygen species (ROS) after the treatment of TEGDMA in its minimal toxic concentration. Materials and methods: HDPCs were obtained from human premolars and were cultured in DMEM under 37 ◦ C until cellular senescence occurred in passage 7. The cytotoxicity caused by TEGDMA to HDPC was estimated using the MTT assay. Minimal toxic concentration (mTc) that HDPC 90% survive was
d e n t a l m a t e r i a l s 2 8 S ( 2 0 1 2 ) e1–e70
determined using dose–response curve. Representative six genes associated with cellular response to ROS were selected for qRT-PCR analysis. qRT-PCR was performed 6 hr, 12 hr, 24 hr and 48 hr after TEGDMA treatment in triplicate. Results: Time-series gene expression change after TEGDMA treatment Gene
6 hr/ control
12 hr/ control
24 hr/ control
48 hr/ control
HMOX1 SOD2 COL1A1 STAT1 DDIT3 SERPINE1
35.83 −1.95 −1.28 −1.41 3.59 4.41
37.45 −2.53 −1.64 −1.53 1.92 2.76
13.62 −3.05 −1.99 −1.28 1.70 2.07
2.10 −6.99 −8.20 −4.52 1.57 3.70
e21
Conclusions: When HDPCs was treated with minimal toxic concentration of TEGDMA, gene expression related to mineralization of pulp cell showed the tendency to be suppressed. http://dx.doi.org/10.1016/j.dental.2012.07.052 46 Delayed crack behavior of veneered Ce-TZP/Al2 O3 discs: The mystery continues A.A. Barrett ∗ , J.J. Mecholsky Jr., K.J. Anusavice
Each value means fold changes of gene expression compared to the control group Conclusions: When HDPC was treated with mTc of TEGDMA, genetic response to ROS occurred relatively early and was followed by the expression change of the genes that regulate cell response to ROS. http://dx.doi.org/10.1016/j.dental.2012.07.051 45 Effect of TEGDMA on mineralization related-gene expression of pulp cell J.H. Lee ∗ , J.W. Lee, S.Y. Kim Kyung Hee University, South Korea Objectives: To investigate early time-series gene expression change related to mineralization of pulp cell after treatment with minimal toxic concentration of TEGDMA. Materials and methods: Human dental pulp cells (HDPCs) were obtained from human premolar. Coronal part was collected and cultured in DMEM under 37 ◦ C until cellular senescence occurred in passage 7. The cytotoxicity caused by TEGDMA to HDPCs was estimated using the MTT Assay. Minimal toxic concentration that 90% of HDPCs survive was determined using dose–response curve. Representative six genes associated with the mineralization were selected for qRT-PCR analysis. The PCR analyses were performed in triplicate for 6 hr, 12 hr, 24 hr, 48 hr after TEGDMA treatment. Results: Time-series gene expression change after TEGDMA treatment Gene
6 hr/ control
12 hr/ control
24 hr/ control
48 hr/ contol
BMP4 JUND SMAD3 COL1A1 BMP6 SPP1
−5.07 −1.80 −1.72 −1.28 1.76 1.87
−4.71 −2.14 −2.11 −1.64 1.41 2.80
−3.76 −1.53 −1.29 −1.99 1.36 6.18
−5.11 −1.34 −1.77 −8.20 2.35 8.58
Each value means fold change of gene expression compared to the control group.
University of Florida College of Dentistry, Gainesville, FL, USA Objectives: Determine the effect of veneer/core ratios on delayed crack formation in a dental veneer bonded to a CeTZP/Al2 O3 core. Materials and methods: Three veneer (v)/core (c) ratios were prepared: 2:1 (0.8v /0.4c mm); 1:1 (0.6v /0.6c mm); 1:2 (0.4v /0.8c mm). Ce-TZP/Al2 O3 discs (Matsushita Ltd., JP) were: abraded (600 grit); blasted (50 m Al2 O3 , 15 s at 10 mm); ‘regenerated’ (15 min at 1000 ◦ C). Ceramic liner was fired (930 ◦ C) onto zirconia discs (12 mm dia), veneered (920 ◦ C) (Shofu Vintage ZRTM System), and finished (15 m diamond). The ceramic (1.2 mm thick) discs (n = 45) were cemented (Panavia F2, Kuraray) onto epoxy-resin substrates (3.6 mm thick). Specimens were aged (DI H2 O at 37 ◦ C) and examined visually and microscopically with fiberoptic illumination after 1 year storage. Veneers underwent microstructural (SEM and EDS) and fractographic analysis; and, the core TEM quantitation (Cliff Lorimer method). Results: After 1 year aqueous storage, no external load applied, unexpected failures included visibly cracked veneers (29%) and partial delaminations. The post immersion fractures for v/c ratios were: 1:1 – 40%; 1:2 – 33%; 2:1 – 13%. Elastic constants were: core: E = 221 GPa, = 29, = 5.28 g/cm3 ; Veneer: E = 77 GPa, = 22, = 2.4 g/cm3 . TEM elemental line scan of the core ceramic indicated a consistent surface composition (atomic wt.%): 7.0% Ce (La1); 55.7% Zr (Ka1); 7.7% Al (Ka1); 29.7% O (Ka1). However, SEM/EDS of the veneers depicted inhomogeneous regions with clusters of zirconia particles (≤2.1 m) distributed within the glassy matrix. Multiscan digital microscopy (VHX Keyence, JP) revealed a tortuous surface with multi-directional fracture markings indicative of residual tensile stress around the particles. Conclusions: The primary cause of veneer cracking in the bilayer discs does not appear to be related to veneer/core ratio. These results suggest that the effects of cooling rate and viscoelastic behaviour need to be investigated. Further research continues, including fractography, in order to determine the causative source of the extreme residual tensile stresses that led to pre-mature veneer fractures. NIH/NIDCR Grant DE06672. http://dx.doi.org/10.1016/j.dental.2012.07.053