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Keywords: Fluorotic enamel; Microtensile test; Silver nanoparticles
Effects of silver nanoparticles on the bonding three adhesive systems
http://dx.doi.org/10.1016/j.dental.2014.08.310
Torres-Gallegos 1 ,
I. G.A. 1,∗ , N.V. Zavala-Alonso 1 , ˜ Martinez-Castanon 1 , J.F. ˜ J.P. Loyola-Rodriguez 1 , N. Patino-Marin 2 , Facundo ˜ Reyes-Macías 1 , N. Nino-Martínez Ruiz 2
310 Influence of fluoride mouthwash containing nanohydroxyapatite on dentin interface microhardness
1
G. Pereira 1,∗ , M. Prado 1 , D.C.R.S. Oliveira 2 , L.R. Menezes 1 , L.T. Prieto 2 , L.A.M.S. Paulillo 2
Autonomous University of San Luis Potosí, San Luis Potosí, Mexico 2 Faculty of Science, Autonomous University of San Luis Potosí, San Luis Potosí, Mexico
1
Purpose: Endemic dental fluorosis has increased in many countries; several researchers have found that dental fluorosis adversely affects the bonding of composites to enamel, thereby compromising clinical success. The need for a simpler and more effective procedure has motivated manufacturers to develop new adhesive systems. The aim of this study was to evaluate the effect of adding silver nanoparticles into three commercial adhesive systems (ExciteTM , Adper Prompt L-PopTM and AdheSETM ) bonded to moderate fluorotic enamel using a micro-tensile bond strength test (TBS). Contact angle was also measured in order to verify the adhesive system wettability. Methods and materials: 10 nm, spherical silver nanoparticles were prepared by a chemical method in an aqueous media, then mixed with the commercial adhesive systems at 1:1 ratio, applied to the fluorotic enamel surface and then micro-tensile bond strength and contact angle measurements were conducted. Results: According to Table 1, the commercial adhesive systems achieved the lowest micro-tensile bond strength with the highest adhesive failure mode related with the highest contact angle. The bond strength achieved in all the experimental adhesive systems was statistically higher and showed the highest cohesive failures related to the lowest contact angle.
Table 1 – Mean microtensile bond strength, failure mode and contact angle of the different adhesive systems. EXTM
TBS (MPa) Contact angle Failure mode
EX+TM
APL-PTM APL-P+TM
ASETM
ASE+TM
Restorative Dentistry Department, Dental School, Federal University of Rio De Janeiro, RJ, Brazil 2 Restorative Dentistry Department, Piracicaba Dental School, State University of Campinas, SP, Brazil Purpose: The aim of this study was to evaluate the influence of a fluoride mouthwash containing nanohydroxyapatite on dentin bonding interface microhardness of direct resin composite restorations. Methods and materials: Forty human premolars were sectioned and restored with a three-step adhesive system (Scotchbond Multi-Purpose, 3M/ESPE) or a self-etch adhesive system (Clearfill SE Bond, Kuraray) with a conventional resinbased composite Filtek Z350XT (3M/ESPE). After the initial microhardness measurements, the restored samples were fixed in acrylic plates for a study in situ. Ten volunteers participated using the plates for one week with the placebo mouthwash, one week as a wash-out, and one week using the testing fluoride mouthwash containing nanohydroxyapatite. The final microhardness measurements were evaluated and data were analyzed by ANOVA and Tukey’s test submitted for multiple comparisons (a = 0.05). Results: There were statistical significant differences between the mouthwash treatments with both adhesive systems tested (p < 0.001). The nanohydroxyapatite used in this in situ mouthwash study was an influencing factor on the dentin interface microhardness of resin composite restorations. Mean values taken from Tukey’s test are shown in Table 1. Table 1
11 ± 2.1© 19 ± 5.4* 14 ± 2* 20 ± 4* 46 ± 0.6 0 30 ± 0.5 0
16 ± 3* 19 ± 3.5* 28 ± 0.4 0
Experimental group
C A M 35 40 25
C A M C A M 40 35 25 55 15 30
Clearfill SE (+ testing mouthwash) Clearfill SE (+ placebo mouthwash) ScotchBond MP (+ testing mouthwash) ScotchBond MP (+ placebo mouthwash)
C A M C A M C A M 45 25 30 30 60 10 40 10 50
n = 120. Results are expressed in MPa. EXTM , Excite; EX+TM , Excite with silver nanoparticles; APL-PTM , Adper Prompt L-Pop; APL-P+TM , Adper Prompt L-Pop with nanoparticles; ASETM , AdheSE; ASE+TM , AdheSE with silver nanoparticles. ©: control group, EXTM group. One-way ANOVA test showed statistically significant differences (p < 0.05) in all the groups when comparing with the control group. There was a statistically significant differences in the failure more (Chi-square test).
Conclusion: Adding silver nanoparticles to the adhesive systems, in order to decrease their contact angle, improve their wettability and their tensile bond strength.
Microhardness Initial
Final
42.59 (0.5) Ba 41.29 (0.5) Aa 42.15 (0.4) Bb
44.33 (0.6) Aa 40.4 (1.0) Ab 45.42 (0.6) Aa
39.66 (0.6) Aab
40.35 (0.5) Ab
Means followed by different capital letters in the same line and small letters in the same column were significantly different (p < 0.05).
Conclusion: The fluoride mouthwash containing nanohydroxyapatite was able to increase the dentin microhardness of direct resin composite restorations regardless the adhesive
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system used; the conventional fluoride mouthwash solution had no influence on dentin microhardness. Keywords: Dentin; Mouthwash; Microhardness http://dx.doi.org/10.1016/j.dental.2014.08.311 311 Bond strength and permeability of HEMA-free adhesives to biomodified dentin R. Bachelar-Sá 1,2,∗ , A.A. Leme 2 , M. Giannini 1 , A.K. Bedran-Russo 2 1
Department of Dental Materials, Piracicaba School of Dentistry, Campinas State University, Piracicaba, Brazil 2 Department of Restorative Dentistry, College of Dentistry, University of Illinois, Chicago, USA Purpose: To assess effect of dentin biomodification on the microtensile bond strength (TBS) and permeability (PA) of four dental adhesive systems (HEMA-containing and HEMA-free). Methods and materials: Seventy-two extracted molars had their occlusal surfaces ground flat to expose dentin. The specimens were assigned into 4 groups of adhesive systems (n = 18): HEMA-containing self-etch adhesive (Scotchbond Universal, SU), two total-etch HEMA-free adhesives (Prime & Bond Elect, PB; All-Bond 3, AB), and one self-etch HEMAfree adhesive (G-Aenial, GA). Each group was divided into 3 experimental sub-groups based on dentin modification (n = 6): control (untreated); 5% glutaraldehyde (GD) for 10 min; and dentin 6.5% proanthocyanidin-rich grape seed extract (PACs) for 10 min. Specimens were sectioned and prepared for TBS. The most promising dentin biomodification strategy (PACs) was selected for permeability studies and compared to control group (no dentin biomodification). Permeability studies were carried out using a simulated pulpal pressure of 140 cm water column at the following time points: presence of smear layer (minimum permeability – Pmin), EDTA treatment 5 min (maximum permeability – Pmax), PACs 10 min (P1), bonding system application (P2) was assessed using EDTA. Measurements were expressed as % of dentinal sealing in relation to Pmax using a hydraulic pressure device. TBS and permeability data were statistically analyzed by two-way ANOVA and Tukey’s tests (p < 0.05). Results: TBS results are shown in the table below. Permeability was reduced when GSE was applied over acid etched surfaces and following application of adhesive systems. There were no short term differences among the permeability of the studied systems.
Resin–dentin microtensile bond strength (MPa), mean (SD) Dental adhesives
No treatment
Glutaraldehyde 5%
Grape seed extract 6.5%
Scotchbond Universala Prime & Bond Electb All-Bond 3c G-Aeniald
55.2 (5.6) A,b
56.9 (6.8) A,a
60.6 (6.9) A,a
51.9 (6.3) A,b
57.2 (10.5) A,a
57.7 (8.2) A,a
48.2 (10.2) A,b 12.2 (7.1) B,b
63.9 (4.4) A,a 13.5 (8.4) B,a
61.1 (8.0) A,a 20.7 (8.8) B,a
Different upper and lower case letters indicates statistically significant differences (p < 0.05) among groups in each column and row, respectively. a b c d
3M ESPE. Dentsply Caulk. Bisco. GC America Corp.
Conclusion: Dentin biomodification significantly increase TBS of dental adhesives systems, regardless of the presence of HEMA. However, GA yielded the lowest TBS among the adhesives tested. PACs and adhesive systems remarkably decrease the permeability of the dentin and dentin–resin interface, respectively. Keywords: Proanthocyanidin; Surface biomodification; Bond strength http://dx.doi.org/10.1016/j.dental.2014.08.312 312 Influence of bisacylphosphine-oxide and chitosan in the physical properties of resins W.C. Brandt 1,∗ , I.D. Silva 1 , D.C. Oliveira 2 , W.R. Sendyk 1 , M.A.C. Sinhoreti 2 , L.C. Boaro 1 1 2
University of Santo Amaro, Brazil University of Campinas, Brazil
Purpose: The objective was to evaluate the degree of conversion (DC), flexural strength (FS) and flexural modulus (FM) of experimental resins containing bisacylphosphine oxide (BAPO) and chitosan (CH). Methods and materials: An experimental resin was prepared with a blend of BisGMA and TEGDMA (50/50 wt%). To this mixture the photoinitiators systems camphorquinone (CQ) or an alternative photoinitiator system BAPO were incorporated. The co-initiator used was the amine dimethylamylamine methylmethacrylate. After, four different concentrations of CH (0.0 wt%, 0.5 wt%, 1 wt% and 2 wt%) were added, producing eight groups for analysis. The photoactivation was made for 20 s with LED BluePhase (Ivoclar) in a matrix with 7 mm × 2 mm × 1 mm (length × width × height). Then, the DC was analyzed in infra-red spectroscopy-FTIR (Spectrum100). FS and FM were tested in a universal testing machine (EMIC - DL500). The means were evaluated by two-way ANOVA and Tukey’s test (5%). Results: According to the results of DC (%), FS (MPa) and FM (GPa) resins containing BAPO showed higher values than resins containing CQ: BAPO(78.4) > CQ(52.3), BAPO(101.4) > CQ(48.5) and BAPO(1.4) > CQ(0.5), respectively. The addition of CH increased the DC and FS values of the resins containing CQ, regardless of the CH concentration used. While