- Email: [email protected]
CAM manufactured veneer crowns with zirconia framework
e92
d e n t a l m a t e r i a l s 2 9 S ( 2 0 1 3 ) e1–e96
adhere to root dentin equal to the current gold standard root filling with gutta-percha and sealer (AH/Gutta). Groups
Composition – EDX (%)
push-out (MPa)
Cohesive
Mixed
AH/Gutta
ZnO 90.6, BaO 6.0, SO3 3.1, SrO 0.08, NiO 0.06 ZnO 30.3%, ZrO2 34.4%, BaO 17.7%, SO3 6.5% TiO2 4.7%, MgO 3.0%, SiO2 2.1%, HfO2 0.6%, CaO 0.3%, SrO 0.13%, Y2 O3 0.04%, Fe2 O3 0.04% ZnO 35%, BaO 32.8%,SO3 15.2%, P2 O5 1.3%, Nb2 O5 1.09%, CaO 0.6%, Fe2 O3 0.32%, Cr2 O3 0.23%
2.83 ± 0.64 (20) a
3.13
78.12
18.75
1.32 ± 0.42 (19) b
30.40
19.20
49.70
2.68 ± 0.84 (20) a
41.73
5.52
52.75
Failure mode (%) Adhesive
Gutta/BC
Gutta/NbG
Different letters indicate a statistical difference (p < 0.05).
http://dx.doi.org/10.1016/j.dental.2013.08.188 expression after chewing simulation (TCS ). Further studies are needed to clarify the effect of chitosan blended within dentin bonding systems.
P4 Bond stability of a chitosan-containing experimental adhesive
http://dx.doi.org/10.1016/j.dental.2013.08.189
M. Diolosà ∗ , I. Donati, S. Paoletti, R. Di Lenarda, L. Breschi, M. Cadenaro
P5
University of Trieste, Trieste, Italy Purpose: The aim of this study was to investigate the influence of aging on bond strength of a chitosan-containing experimental adhesive, assayed with microtensile bond strength test (TBS) and nanoleakage analysis. Methods and materials: Sixteen extracted third human molars were selected and flat dentin surface was exposed and assigned to two groups (N = 8) after acid-etching: Group 1: a chitosan containing primer followed by an unsolvated bonding agent (R2: 70% BisGMA, 28.75% TEGDMA, 0.5% EDMAB, 0.5% TPO, 0.25% CQ); Group 2 (control): a primer without chitosan (30% HEMA, 20% ethanol, 50% MES) followed by R2. A layer of resin composite (Filtek Z250, 3 M ESPE) was placed over the bonded surface and polymerized. Specimens were processed for TBS in accordance with the non-trimming technique and pulled to failure either after Chewing Simulation (TCS; 37 ◦ C in 0.5 mL artificial saliva, submitted to 50 N occlusal load, 1 Hz, up to 1,200,000 cycles) or after storage in artificial saliva at 37 ◦ C for the same time (approximately 3 weeks; T0 ). Additional specimens were similarly processed to investigate nanoleakage expression under light microscopy and SEM. Statistical analysis was performed with the Mann–Whitney U-test (p < 0.05). Results: TBS values are reported in Table 1. Table 1 – Means ± SD of mTBS (MPa). Adhesive system Group 1 Group 2
TCS 28.38 ± 8.78aA 17.98 ± 6.01bB
T0 26.04 ± 8.73aA 25.45 ± 8.67aA
Different superscript lower case letters indicate a statistical difference in column and different superscript capital letters indicate a statistical difference in rows (p < 0.05).
Conclusion: Chitosan addition to the experimental primer affected the bond strength and interfacial nanoleakage
Fracture resistance of CAD/CAM manufactured veneer crowns with zirconia framework A.K. Figueiredo Costa ∗ , J.M.C. Lima, L.C. Anami, A.L.S. Borges, R.M. Melo, R.O. Assunc¸ão, E. Souza, M.A. Bottino Univ Estadual Paulista, Brazil Purpose: The aim of this study was to evaluate the in vitro influence of the thickness of veneering ceramics on the fracture resistance of zirconia based crowns veneered with CAD/CAM manufactured ceramic. Methods and materials: 20 identical zirconia1 frameworks (1.0 mm thickness) were manufactured by CAD/CAM2 and 20 crowns with two different occlusal thicknesses (Groups TF1 = 1.0 mm and TF2 = 2.0 mm; n = 10) were milled using a CAD/CAM manufactured feldspathic ceramic3 veneer that was cemented onto zirconia frameworks using resin cement4. All crowns were mechanically cycled (Fmax = 200 N; 2,000,000 cycles; 3.0 Hz) and after the cycling the presence of chipping and delamination was observed on a stereomicroscope. The fracture test was performed (0.5 mm/min, 1000 kgf load cell), the failure mode was classified and the failure origin was determined as well. The data (in kgf) were statistically analyzed using t-Student test (5%). 1Vita In-Ceram YZ, Vita Zahnfabrik. 2CEREC InLab MC XL, Sirona Dental Systems. 3Vita TriLuxe Forte, Vita Zahnfabrik. 4Panavia F 2.0, Kuraray. Results: The mean values and standard deviation of the maximum fracture strength (kgf) and coefficient of variation for each experimental group (n = 10) were respectively: TF1 n 148.2 ± 31.4; 21.24 and TF2 n 211.0 ± 33.1; 15.70. For t-Student test TF1 and TF2 showed statistical difference (p < 0.05). Table 1 shows the classification of failure mode according to the classification in cracking, chipping, delamination and catastrophic fracture and according to Burkeís classification.
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d e n t a l m a t e r i a l s 2 9 S ( 2 0 1 3 ) e1–e96
Table 1 Burke’s classificationb TF1 TF2 a
b
Cracking/chippinga
Delaminationa
Type I
Type II
Type III
Type IV
Catastrophic fracturea Type V
0 0
5 (50%) 4 (40%)
0 2 (20%)
3 (30%) 3 (30%)
2 (20%) 1 (10%)
Cracking = veneer ceramic cracked at the interface; chipping = fracture in the veneer ceramic surface without exposure of the zirconia infrastructure; delamination = veneer ceramic was damaged and the infrastructure exposed; catastrophic fracture = fracture in both the veneer ceramic and the infrastructure. Type I – Minimal fracture or crack in crown; Type II – Less than half of crown lost; Type III – Crown fracture through midline with half of crown displaced or lost; Type IV – More than half of crown lost; Type V – Severe fracture of tooth and/or crown.
Conclusion: The all-ceramic crowns with 2 mm thickness on the occlusal surface showed higher fracture resistance and the use of CAD/CAM to produce all parts of all ceramic crowns is feasible and shows promising results. http://dx.doi.org/10.1016/j.dental.2013.08.190 P6 Chewing simulation affects dentin collagen degradation A. Frassetto 1,∗ , G. Turco 1 , A. Mazzoni 1 , M. Cadenaro 1 , F.R. Tay 2 , D.H. Pashley 2 , L. Breschi 1 1 2
University of Trieste, Trieste, Italy Georgia Regents University, Augusta, GA, USA
Purpose: Previous studies reported that cathepsins could contribute to the degradation of the dentin collagen network, however no information is available on the role of occlusal forces on the enzymatic activity. This study evaluated the effect of chewing simulation (CS) on the degradation of the dentin collagen matrix due to activated cathepsins by measuring CTX fragment release. The tested hypothesis was that CS has no influence on the degradation of collagen. Methods and materials: Dentin slabs 1.0 ± 0.1 mm-thick were obtained from human sound teeth and completely
demineralized in 10 wt% phosphoric acid (pH = 1) for 24 h at 25 ◦ C. After demineralization the demineralized specimens were cut in circular disks of 6.0 ± 0.2 mm in diameter using a surgical biopsy punch. Demineralized specimens were then submitted either to CS (37 ◦ C in 0.5 mL artificial saliva, submitted to 50 N occlusal load, 30 s occlusal time plus 30s with no load, 1 Hz, up to 30 days) in sealed chambers or statically stored in artificial saliva and complete medium (12.92 mM KCl, 1.95 mM KSCN, 2.37 mM Na2 SO4 ·10H2 O, 3.33 mM NH4 Cl, 1.55 mM CaCl2 ·2H2 O, 7.51 mM NaHCO3 , 0.02 mM ZnCl2 , 5 mM HEPES buffer), and tested at increasing time intervals up to 30 days. Cathepsins activity was assayed quantifying CTX collagen fragments using an ELISA test at 1, 2, 3, 4, 5, 6, 7, 10, 14, 21 and 30 days. The data were analyzed using t-test for independent data. Results: Results are shown in Fig. 1. Conclusion: The tested hypothesis was rejected since significant differences were observed in the CTX release in relation to the CS procedure compared to controls. Demineralized dentin stored in static conditions showed higher endogenous telopeptidase activity, as indirect evidence of cathepsins K activity, compared to CS specimens. Supported, in part, by grants: FIRB RBAP1095CR and PRIN 2009SAN9K5 and 2009FXT3WL from MIUR, Italy and by R01 DE015306 from the NIDCR to DHP (PI). http://dx.doi.org/10.1016/j.dental.2013.08.191
Fig. 1 – Release of CTX collagen fragments at different time intervals. *Significant differences.
d e n t a l m a t e r i a l s 2 9 S ( 2 0 1 3 ) e1–e96
adhere to root dentin equal to the current gold standard root filling with gutta-percha and sealer (AH/Gutta). Groups
Composition – EDX (%)
push-out (MPa)
Cohesive
Mixed
AH/Gutta
ZnO 90.6, BaO 6.0, SO3 3.1, SrO 0.08, NiO 0.06 ZnO 30.3%, ZrO2 34.4%, BaO 17.7%, SO3 6.5% TiO2 4.7%, MgO 3.0%, SiO2 2.1%, HfO2 0.6%, CaO 0.3%, SrO 0.13%, Y2 O3 0.04%, Fe2 O3 0.04% ZnO 35%, BaO 32.8%,SO3 15.2%, P2 O5 1.3%, Nb2 O5 1.09%, CaO 0.6%, Fe2 O3 0.32%, Cr2 O3 0.23%
2.83 ± 0.64 (20) a
3.13
78.12
18.75
1.32 ± 0.42 (19) b
30.40
19.20
49.70
2.68 ± 0.84 (20) a
41.73
5.52
52.75
Failure mode (%) Adhesive
Gutta/BC
Gutta/NbG
Different letters indicate a statistical difference (p < 0.05).
http://dx.doi.org/10.1016/j.dental.2013.08.188 expression after chewing simulation (TCS ). Further studies are needed to clarify the effect of chitosan blended within dentin bonding systems.
P4 Bond stability of a chitosan-containing experimental adhesive
http://dx.doi.org/10.1016/j.dental.2013.08.189
M. Diolosà ∗ , I. Donati, S. Paoletti, R. Di Lenarda, L. Breschi, M. Cadenaro
P5
University of Trieste, Trieste, Italy Purpose: The aim of this study was to investigate the influence of aging on bond strength of a chitosan-containing experimental adhesive, assayed with microtensile bond strength test (TBS) and nanoleakage analysis. Methods and materials: Sixteen extracted third human molars were selected and flat dentin surface was exposed and assigned to two groups (N = 8) after acid-etching: Group 1: a chitosan containing primer followed by an unsolvated bonding agent (R2: 70% BisGMA, 28.75% TEGDMA, 0.5% EDMAB, 0.5% TPO, 0.25% CQ); Group 2 (control): a primer without chitosan (30% HEMA, 20% ethanol, 50% MES) followed by R2. A layer of resin composite (Filtek Z250, 3 M ESPE) was placed over the bonded surface and polymerized. Specimens were processed for TBS in accordance with the non-trimming technique and pulled to failure either after Chewing Simulation (TCS; 37 ◦ C in 0.5 mL artificial saliva, submitted to 50 N occlusal load, 1 Hz, up to 1,200,000 cycles) or after storage in artificial saliva at 37 ◦ C for the same time (approximately 3 weeks; T0 ). Additional specimens were similarly processed to investigate nanoleakage expression under light microscopy and SEM. Statistical analysis was performed with the Mann–Whitney U-test (p < 0.05). Results: TBS values are reported in Table 1. Table 1 – Means ± SD of mTBS (MPa). Adhesive system Group 1 Group 2
TCS 28.38 ± 8.78aA 17.98 ± 6.01bB
T0 26.04 ± 8.73aA 25.45 ± 8.67aA
Different superscript lower case letters indicate a statistical difference in column and different superscript capital letters indicate a statistical difference in rows (p < 0.05).
Conclusion: Chitosan addition to the experimental primer affected the bond strength and interfacial nanoleakage
Fracture resistance of CAD/CAM manufactured veneer crowns with zirconia framework A.K. Figueiredo Costa ∗ , J.M.C. Lima, L.C. Anami, A.L.S. Borges, R.M. Melo, R.O. Assunc¸ão, E. Souza, M.A. Bottino Univ Estadual Paulista, Brazil Purpose: The aim of this study was to evaluate the in vitro influence of the thickness of veneering ceramics on the fracture resistance of zirconia based crowns veneered with CAD/CAM manufactured ceramic. Methods and materials: 20 identical zirconia1 frameworks (1.0 mm thickness) were manufactured by CAD/CAM2 and 20 crowns with two different occlusal thicknesses (Groups TF1 = 1.0 mm and TF2 = 2.0 mm; n = 10) were milled using a CAD/CAM manufactured feldspathic ceramic3 veneer that was cemented onto zirconia frameworks using resin cement4. All crowns were mechanically cycled (Fmax = 200 N; 2,000,000 cycles; 3.0 Hz) and after the cycling the presence of chipping and delamination was observed on a stereomicroscope. The fracture test was performed (0.5 mm/min, 1000 kgf load cell), the failure mode was classified and the failure origin was determined as well. The data (in kgf) were statistically analyzed using t-Student test (5%). 1Vita In-Ceram YZ, Vita Zahnfabrik. 2CEREC InLab MC XL, Sirona Dental Systems. 3Vita TriLuxe Forte, Vita Zahnfabrik. 4Panavia F 2.0, Kuraray. Results: The mean values and standard deviation of the maximum fracture strength (kgf) and coefficient of variation for each experimental group (n = 10) were respectively: TF1 n 148.2 ± 31.4; 21.24 and TF2 n 211.0 ± 33.1; 15.70. For t-Student test TF1 and TF2 showed statistical difference (p < 0.05). Table 1 shows the classification of failure mode according to the classification in cracking, chipping, delamination and catastrophic fracture and according to Burkeís classification.
e93
d e n t a l m a t e r i a l s 2 9 S ( 2 0 1 3 ) e1–e96
Table 1 Burke’s classificationb TF1 TF2 a
b
Cracking/chippinga
Delaminationa
Type I
Type II
Type III
Type IV
Catastrophic fracturea Type V
0 0
5 (50%) 4 (40%)
0 2 (20%)
3 (30%) 3 (30%)
2 (20%) 1 (10%)
Cracking = veneer ceramic cracked at the interface; chipping = fracture in the veneer ceramic surface without exposure of the zirconia infrastructure; delamination = veneer ceramic was damaged and the infrastructure exposed; catastrophic fracture = fracture in both the veneer ceramic and the infrastructure. Type I – Minimal fracture or crack in crown; Type II – Less than half of crown lost; Type III – Crown fracture through midline with half of crown displaced or lost; Type IV – More than half of crown lost; Type V – Severe fracture of tooth and/or crown.
Conclusion: The all-ceramic crowns with 2 mm thickness on the occlusal surface showed higher fracture resistance and the use of CAD/CAM to produce all parts of all ceramic crowns is feasible and shows promising results. http://dx.doi.org/10.1016/j.dental.2013.08.190 P6 Chewing simulation affects dentin collagen degradation A. Frassetto 1,∗ , G. Turco 1 , A. Mazzoni 1 , M. Cadenaro 1 , F.R. Tay 2 , D.H. Pashley 2 , L. Breschi 1 1 2
University of Trieste, Trieste, Italy Georgia Regents University, Augusta, GA, USA
Purpose: Previous studies reported that cathepsins could contribute to the degradation of the dentin collagen network, however no information is available on the role of occlusal forces on the enzymatic activity. This study evaluated the effect of chewing simulation (CS) on the degradation of the dentin collagen matrix due to activated cathepsins by measuring CTX fragment release. The tested hypothesis was that CS has no influence on the degradation of collagen. Methods and materials: Dentin slabs 1.0 ± 0.1 mm-thick were obtained from human sound teeth and completely
demineralized in 10 wt% phosphoric acid (pH = 1) for 24 h at 25 ◦ C. After demineralization the demineralized specimens were cut in circular disks of 6.0 ± 0.2 mm in diameter using a surgical biopsy punch. Demineralized specimens were then submitted either to CS (37 ◦ C in 0.5 mL artificial saliva, submitted to 50 N occlusal load, 30 s occlusal time plus 30s with no load, 1 Hz, up to 30 days) in sealed chambers or statically stored in artificial saliva and complete medium (12.92 mM KCl, 1.95 mM KSCN, 2.37 mM Na2 SO4 ·10H2 O, 3.33 mM NH4 Cl, 1.55 mM CaCl2 ·2H2 O, 7.51 mM NaHCO3 , 0.02 mM ZnCl2 , 5 mM HEPES buffer), and tested at increasing time intervals up to 30 days. Cathepsins activity was assayed quantifying CTX collagen fragments using an ELISA test at 1, 2, 3, 4, 5, 6, 7, 10, 14, 21 and 30 days. The data were analyzed using t-test for independent data. Results: Results are shown in Fig. 1. Conclusion: The tested hypothesis was rejected since significant differences were observed in the CTX release in relation to the CS procedure compared to controls. Demineralized dentin stored in static conditions showed higher endogenous telopeptidase activity, as indirect evidence of cathepsins K activity, compared to CS specimens. Supported, in part, by grants: FIRB RBAP1095CR and PRIN 2009SAN9K5 and 2009FXT3WL from MIUR, Italy and by R01 DE015306 from the NIDCR to DHP (PI). http://dx.doi.org/10.1016/j.dental.2013.08.191
Fig. 1 – Release of CTX collagen fragments at different time intervals. *Significant differences.