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Effect of film thickness of resin cement on indirect restoration
e136
d e n t a l m a t e r i a l s 2 6 ( 2 0 1 0 ) e125–e157
of CPP–ACP paste with artificial saliva group was significantly higher than the others. Conclusions. The CPP–ACP paste cannot prevent hardness reduction of enamel after erosion by a Cola drink in vitro. The CPP–ACP paste with artificial saliva group showed significantly less enamel hardness reduction.
Reference
doi:10.1016/j.dental.2009.11.101
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Effect of film thickness of resin cement on indirect restoration
Influence of ammonium hexafluorosilicate on enamel of permanent teeth I.I.
Vega ∗ ,
C.A. Alvarez, D. Cortes
Universidad Nacional Autónoma De México, Mexico Objectives. Although diamine silver fluoride (1 AgF: (NH3 )2 AgF) stains teeth black, it is known as a very effective agent to prevent the dental caries progress [1]. The Ammonium hexafluorosilicate (2 SiF: (NH4 )2 SiF6 ), could be used as an alternative treatment without stains. The aim of this study was to determine and compare the resistance to demineralization of the enamel of permanent teeth, with SiF and AgF application. Materials and methods. 30 surgically extracted human third molars were mounted in polymethylmethacrylate on vestibular side and polished to a #2500 SiC grade in order to get a 3 mm × 3 mm enamel area. Samples were washed with ultrasound and divided into 3 groups (Control, AgF and SIF) of 10 samples each. Microhardness measurements were made with a Vickers indenter (MXT30-UL. series UL0023). Enamel blocks were immersed in a demineralizing solution (0.1 mol lactic acid, 3 mmol/L CaCl2 , 1.8 mmol/L K2 PO4 , containing 1 wt% carboxymethylcellulose, solution pH was adjusted to 4.0 with KOH) for one hour at 37 ◦ C in three cycles. On two of the groups before placement in the demineralizing solution SiF (0.476 mol/L) and AgF (2.36 mol/L) were applied, respectively, for 3 min and washed with deionized water. All samples were analyzed by microhardness measurements between applications. For the statistical analysis, one-way factorial ANOVA and Tukey, used as a post-hoc test, were performed using the SPSS program. Results Group
Initial hardness (GPa)
1st cycle hardness (GPa)
2nd cycle hardness (GPa)
3rd cycle hardness (Gpa)
Control AgF SiF
3.5437 3.5138 3.5836
1.8970 2.7522 2.9795
1.3373 2.5704 2.2209
0.8424 2.2786 2.1807
ANOVA test found statistically significant differences between groups (p < 0.0001). Tukey test found differences after demineralization process between control and experimental groups (p < 0.001). No differences were found between SiF and AgF groups, neither the number of applications (p > 0.05). Conclusions. SiF use is a very good option since does not stain and provides the same level of acidity protection as AgF.
[1] Toshiyuki, et al. J Osaka Dent 1969;9:61.
doi:10.1016/j.dental.2009.11.102
K.K. Choi, S.H. Lee KyungHee University, South Korea Objectives. Adequate film thickness of resin cement is needed for long-term retention of restoration. The purpose of this study was to evaluate the effect of film thickness of various resin cements on bonding efficiency in indirect composite restoration. Materials and methods. Experimental groups were divided according to film thickness (<50–150 m) using 2 kinds of composite-based resin cements (Variolink II, Duo-Link) and 2 kinds of adhesive-based resin cement (Panavia F, Rely X Unicem). For microtensile bond strength test, indirect composite block (TesceraTM : Bisco) was luted to flat dentin surface with each adhesive cement under pressure of 0.5 kgf. The bonded tooth-resin block was stored in distilled water at 37 ◦ C for 24 h and sectioned into 1 × 1 mm beams. These specimens were tested with universal testing machine at a crosshead speed of 1 mm/min. Polymerization shrinkage of resin cements was determined with ACUVOLTM (Bisco) before and after polymerization. Flexural strength and modulus were measured by three-point bending test. Cement/dentin interface and debonded dentin surface were examined with FE-SEM (Zeiss). All data were analyzed using one-way ANOVA and Duncan’s multiple comparison test at ˛ ≤ 0.05 level. Results 1. Composite-based resin cements showed higher microtensile bond strength for all film thickness than that of adhesive-based resin cements. 2. Microtensile bond strength of composite-based resin cements was decreased significantly according to increasing film thickness, but adhesive-based resin cements did not show significant difference among the film thickness. 3. Composite-based resin cements showed significantly higher flexural strength, modulus and shrinkage than those of adhesive-based resin cements. 4. Uniform adhesive layer and well-developed resin tags were observed in composite-based resin cements and the debonded surface showed mixed-failed in FE-SEM. Conclusions. The bonding performance and efficiency of indirect restoration can be affected by type of resin cements, adhesive system and film thickness. doi:10.1016/j.dental.2009.11.103
d e n t a l m a t e r i a l s 2 6 ( 2 0 1 0 ) e125–e157
of CPP–ACP paste with artificial saliva group was significantly higher than the others. Conclusions. The CPP–ACP paste cannot prevent hardness reduction of enamel after erosion by a Cola drink in vitro. The CPP–ACP paste with artificial saliva group showed significantly less enamel hardness reduction.
Reference
doi:10.1016/j.dental.2009.11.101
24
23
Effect of film thickness of resin cement on indirect restoration
Influence of ammonium hexafluorosilicate on enamel of permanent teeth I.I.
Vega ∗ ,
C.A. Alvarez, D. Cortes
Universidad Nacional Autónoma De México, Mexico Objectives. Although diamine silver fluoride (1 AgF: (NH3 )2 AgF) stains teeth black, it is known as a very effective agent to prevent the dental caries progress [1]. The Ammonium hexafluorosilicate (2 SiF: (NH4 )2 SiF6 ), could be used as an alternative treatment without stains. The aim of this study was to determine and compare the resistance to demineralization of the enamel of permanent teeth, with SiF and AgF application. Materials and methods. 30 surgically extracted human third molars were mounted in polymethylmethacrylate on vestibular side and polished to a #2500 SiC grade in order to get a 3 mm × 3 mm enamel area. Samples were washed with ultrasound and divided into 3 groups (Control, AgF and SIF) of 10 samples each. Microhardness measurements were made with a Vickers indenter (MXT30-UL. series UL0023). Enamel blocks were immersed in a demineralizing solution (0.1 mol lactic acid, 3 mmol/L CaCl2 , 1.8 mmol/L K2 PO4 , containing 1 wt% carboxymethylcellulose, solution pH was adjusted to 4.0 with KOH) for one hour at 37 ◦ C in three cycles. On two of the groups before placement in the demineralizing solution SiF (0.476 mol/L) and AgF (2.36 mol/L) were applied, respectively, for 3 min and washed with deionized water. All samples were analyzed by microhardness measurements between applications. For the statistical analysis, one-way factorial ANOVA and Tukey, used as a post-hoc test, were performed using the SPSS program. Results Group
Initial hardness (GPa)
1st cycle hardness (GPa)
2nd cycle hardness (GPa)
3rd cycle hardness (Gpa)
Control AgF SiF
3.5437 3.5138 3.5836
1.8970 2.7522 2.9795
1.3373 2.5704 2.2209
0.8424 2.2786 2.1807
ANOVA test found statistically significant differences between groups (p < 0.0001). Tukey test found differences after demineralization process between control and experimental groups (p < 0.001). No differences were found between SiF and AgF groups, neither the number of applications (p > 0.05). Conclusions. SiF use is a very good option since does not stain and provides the same level of acidity protection as AgF.
[1] Toshiyuki, et al. J Osaka Dent 1969;9:61.
doi:10.1016/j.dental.2009.11.102
K.K. Choi, S.H. Lee KyungHee University, South Korea Objectives. Adequate film thickness of resin cement is needed for long-term retention of restoration. The purpose of this study was to evaluate the effect of film thickness of various resin cements on bonding efficiency in indirect composite restoration. Materials and methods. Experimental groups were divided according to film thickness (<50–150 m) using 2 kinds of composite-based resin cements (Variolink II, Duo-Link) and 2 kinds of adhesive-based resin cement (Panavia F, Rely X Unicem). For microtensile bond strength test, indirect composite block (TesceraTM : Bisco) was luted to flat dentin surface with each adhesive cement under pressure of 0.5 kgf. The bonded tooth-resin block was stored in distilled water at 37 ◦ C for 24 h and sectioned into 1 × 1 mm beams. These specimens were tested with universal testing machine at a crosshead speed of 1 mm/min. Polymerization shrinkage of resin cements was determined with ACUVOLTM (Bisco) before and after polymerization. Flexural strength and modulus were measured by three-point bending test. Cement/dentin interface and debonded dentin surface were examined with FE-SEM (Zeiss). All data were analyzed using one-way ANOVA and Duncan’s multiple comparison test at ˛ ≤ 0.05 level. Results 1. Composite-based resin cements showed higher microtensile bond strength for all film thickness than that of adhesive-based resin cements. 2. Microtensile bond strength of composite-based resin cements was decreased significantly according to increasing film thickness, but adhesive-based resin cements did not show significant difference among the film thickness. 3. Composite-based resin cements showed significantly higher flexural strength, modulus and shrinkage than those of adhesive-based resin cements. 4. Uniform adhesive layer and well-developed resin tags were observed in composite-based resin cements and the debonded surface showed mixed-failed in FE-SEM. Conclusions. The bonding performance and efficiency of indirect restoration can be affected by type of resin cements, adhesive system and film thickness. doi:10.1016/j.dental.2009.11.103