Publications by authors named "Elham Ansarifard"

7 Publications

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The effect of bleaching on the optical and physical properties of externally stained monolithic zirconia.

Clin Exp Dent Res 2021 Jun 21. Epub 2021 Jun 21.

Department of Prosthodontics, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.

Objective: This study aimed to investigate the effects of bleaching on the color, translucency, surface roughness, and surface hardness of monolithic zirconia with external stainin .

Methods: In this experimental study, 32 specimens of monolithic zirconia (1 × 1 mm; shade A2) were divided into two groups based on random permuted blocks. Overglaze and staining procedures were performed with a yellow stain or a value stain (GC Stain). Baseline color, translucency, roughness, and surface hardness were measured. The specimens were then randomly bleached with hydrogen peroxide (HP) 40% (20 min, twice with a 1-week interval in between) as office bleaching or carbamide peroxide (CP) 20% (4 h per day for 14 days) as home bleaching. Finally, the color, translucency, surface roughness, and surface hardness were measured again.

Results: Bleaching with CP and HP caused a perceptible change in the color of the specimens (ΔE > 2), although this change was within the clinically acceptable range (ΔE < 3.3). HP significantly reduced the surface hardness of the specimens (p = 0.043). Changes in surface roughness of the specimens were neither statistically nor clinically significant (p = 0.19 and p = 0.25 for office and home bleaching, respectively).

Conclusion: The effects of home and office bleaching on the surface characteristics of monolithic zirconia were almost the same. It is not necessary to exchange or even to polish the surfaces of zirconia restorations after exposure to bleaching agents. Further studies are recommended to confirm the color stability of externally stained monolithic zirconia.
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http://dx.doi.org/10.1002/cre2.433DOI Listing
June 2021

Evaluation of Antimicrobial and Antibiofilm Activities of Copper Oxide Nanoparticles within Soft Denture Liners against Oral Pathogens.

Bioinorg Chem Appl 2021 4;2021:9939275. Epub 2021 Jun 4.

Department of Parasitology and Mycology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.

Objectives: Soft denture liners provide a favorable environment for adhesion and colonization of microorganisms. This in vitro study aimed to examine the efficacy of different concentrations of copper oxide nanoparticles (CuO NPs) incorporation into soft denture liner on the biofilm formation of the microbial species.

Methods: Field Emission Scanning Electron Microscopy (FESEM) images from NPs were recorded. Antifungal susceptibility testing of CuO NPs against five standard strains of (CBS 10261, 1905, 1912, 1949, 2730), (ATCC35668), (ATCC27607), and ATCC9222) was performed by the broth microdilution method with the Clinical and Laboratory Standards Institute reference method. The biofilm inhibition percentages of CuO NPs on the soft denture liners were determined by XTT assay.

Results: The characterization of CuO NPs by scanning electron microscope (SEM) analyses confirmed the synthesis of NPs with appropriate structure and size with a mean diameter of 18.3 ± 9.1 nm. The CuO NPs successfully inhibited the growth of the tested standard strains of nd spp. at concentrations ranging from 64 to 128 g mL. Indeed, incorporation of CuO NPs at a concentration of 500 g mL into the soft denture liners exhibited a significant activity (75%) in inhibition of . biofilm formation in a dose-dependent manner. The biofilm formation of in the presence of CuO NPs was lower than spp. in comparison with the control group ( < 0.05).

Conclusion: Incorporation of CuO NPs significantly decreased the colonization and plaque formation of the oral pathogens, especially accumulation. These NPs may be useful as a promising agent for the antimicrobial management of soft denture liner materials.
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http://dx.doi.org/10.1155/2021/9939275DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8195668PMC
June 2021

Evaluation of microhardness and water sorption/solubility of dual-cure resin cement through monolithic zirconia in different shades.

J Indian Prosthodont Soc 2021 Jan-Mar;21(1):50-56

Department of Prosthodontics, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.

Aim: The objective is to evaluate the effect of shades of monolithic zirconia on the microhardness and sorption/solubility of the underlying two dual-cured resin types of cement.

Materials And Methods: Eighty samples of two dual-cured resin cement discs were polymerized under 60 monolithic zirconia discs in three shades and directly activated resin discs of cement were used as the control group (n = 10). After 24 h storage at 37°C in an incubator, Vickers microhardness and the sorption and solubility were measured.

Statistical Analysis Used: Two-way ANOVA , one-way ANOVA, Independent t-test, Tukey's honestly significant difference, and Tamhane's T2 tests.

Results: The mean microhardness of the Variolink N resin cements were significantly higher than Panavia SA ones (P < 0.001). Furthermore, Variolink N cements exhibited lower sorption/solubility than Panavia SA resin cements (both P < 0.05). The ceramic shade had a significant influence on the microhardness of both cements (P < 0.001) but had no significant effect on the sorption/solubility of resin cements (P > 0.05).

Conclusion: Interposition of monolithic zirconia decreases the microhardness of resin cement especially Panavia SA. In Variolink N, by increasing the chroma saturation of ceramics, the microhardness decreased, however in Panavia SA, it was altered by the shades, but not in a specific pattern. For both cements, there were no statistical differences between the sorption/solubility of samples photo-cured under different shades. There was a reverse correlation between microhardness and water sorption/solubility of both cements.
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http://dx.doi.org/10.4103/jips.jips_284_20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8061437PMC
July 2021

Marginal Fit of Full Contour Monolithic Zirconia in Different Thicknesses and Layered Zirconia Crowns.

J Int Soc Prev Community Dent 2020 Sep-Oct;10(5):652-658. Epub 2020 Sep 28.

School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.

Aim: Use of monolithic zirconia for fabrication of all-ceramic crowns eliminates several shortcomings of layered zirconia crowns. Long-term success of restorations highly depends on the marginal fit. The crown thickness is among the factors that affect the marginal integrity. Meanwhile, reduced thickness of crowns has several advantages such as preservation of tooth structure. The aim of this study was to evaluate the marginal fit of monolithic zirconia crowns in reduced thickness and to compare the marginal fit of full-contour monolithic zirconia in different thicknesses with layered zirconia crowns.

Materials And Methods: In this study, two standard brass dies (7 mm × 5 mm length diameter) were prepared with a heavy chamfer finish line with 0.5 and 1 mm depth. By using a CAD-CAM system, 30 crowns were made in three groups ( = 10) of 1-mm thick layered zirconia, 1-mm thick monolithic zirconia, and 0.5-mm thick monolithic zirconia. Crowns were placed on master dies and randomly numbered. The marginal gap was measured on 18 points by using a digital microscope (×230). The mean ± standard deviation (SD) values were calculated and analyzed by Statistical Package for the Social Sciences (SPSS) software program through Kruskal-Wallis and Mann-Whitney tests (α = 0.05).

Results: The marginal gap of 1-mm layered zirconia was significantly different from that of 1-mm monolithic zirconia ( = 0.001) and 0.5-mm monolithic zirconia ( = 0.004). Analysis of variance (ANOVA) revealed no significant difference between 0.5 and 1 mm thicknesses of monolithic zirconia ( = 0.141).

Conclusion: Marginal gap in all the three groups was clinically acceptable. The two different thicknesses of monolithic zirconia crowns had no significant effect on the restoration marginal fit; however, layered zirconia crowns showed a significantly higher marginal gap than monolithic zirconia crowns.
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http://dx.doi.org/10.4103/jispcd.JISPCD_25_20DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7685281PMC
September 2020

Effect of different coloring techniques and surface treatment methods on the surface roughness of monolithic zirconia.

Dent Res J (Isfahan) 2020 Mar-Apr;17(2):152-161. Epub 2020 Mar 17.

Department of Prosthodontics, Biomaterials Research Center, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.

Background: This study aimed to evaluate the effect of different coloring techniques and surface treatment methods on the surface roughness of monolithic zirconia ceramic.

Materials And Methods: In this study seventy-two disk-shaped monolithic zirconia (2 mm × 10 mm) were divided into three coloring techniques groups (white, internal staining, external staining) ( = 24). Each group was subdivided into four surface treatment subgroups ( = 6), as unpolished, polished with Shofu polishing kit, polished with dental direct polishing kit, and glazed. Profilometer was used to measure the Ra (roughness average) and Rz (roughness height) surface roughness values (μm) and scanning electron microscopy (SEM) for visual inspection of the surface morphology. The surface roughness parameters were calculated and analyzed with two-way ANOVA and Tukey's test (α = 0.05).

Results: The coloring technique, surface treatment method, and interaction of these two parameters significantly affected the Ra and Rz parameters ( < 0.05). Concerning the surface treatment, the Rz value was significantly higher in the unpolished subgroup, followed by the glazed and polished subgroups. However, the two polishing systems were not significantly different. The internal staining group had significantly higher Rz value than the other staining method, when the specimens were glazed or polished with Shofu kit. SEM showed multiple scratches in unpolished samples which were smoothened by glazing and specially by polishing.

Conclusion: Among all the studied surface treatment methods, the lowest surface roughness was observed in highly polished monolithic zirconia, which was even less than the glazed one. The internal staining method can create a rougher surface for some of the surface treatment methods.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7224263PMC
March 2020

Accuracy of different impression materials in parallel and nonparallel implants.

Dent Res J (Isfahan) 2015 Jul-Aug;12(4):315-22

Department of Prosthodontics, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.

Background: A precise impression is mandatory to obtain passive fit in implant-supported prostheses. The aim of this study was to compare the accuracy of three impression materials in both parallel and nonparallel implant positions.

Materials And Methods: In this experimental study, two partial dentate maxillary acrylic models with four implant analogues in canines and lateral incisors areas were used. One model was simulating the parallel condition and the other nonparallel one, in which implants were tilted 30° bucally and 20° in either mesial or distal directions. Thirty stone casts were made from each model using polyether (Impregum), additional silicone (Monopren) and vinyl siloxanether (Identium), with open tray technique. The distortion values in three-dimensions (X, Y and Z-axis) were measured by coordinate measuring machine. Two-way analysis of variance (ANOVA), one-way ANOVA and Tukey tests were used for data analysis (α = 0.05).

Results: Under parallel condition, all the materials showed comparable, accurate casts (P = 0.74). In the presence of angulated implants, while Monopren showed more accurate results compared to Impregum (P = 0.01), Identium yielded almost similar results to those produced by Impregum (P = 0.27) and Monopren (P = 0.26).

Conclusion: Within the limitations of this study, in parallel conditions, the type of impression material cannot affect the accuracy of the implant impressions; however, in nonparallel conditions, polyvinyl siloxane is shown to be a better choice, followed by vinyl siloxanether and polyether respectively.
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http://dx.doi.org/10.4103/1735-3327.161429DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4533188PMC
August 2015

Effects of oxalate desensitizer with different resin cement-retained indirect composite inlays on fracture resistance of teeth.

J Prosthodont 2013 Jun 20;22(4):268-74. Epub 2012 Dec 20.

Department of Operative Dentistry, School of Dentistry, Shiraz University of Medical Sciences, Iran.

Purpose: This study investigated whether the tubular occluding effect of oxalate desensitizer (OX) during adhesive cementation (three resin cements) influenced fracture resistance of teeth restored with adhesive inlays.

Materials And Methods: Ninety intact maxillary premolars were randomly divided into 9 groups of 10 each. The two control groups were Gr 1, intact teeth and Gr 2, mesio-occlusodistal preparation only. In six experimental groups, the composite inlays were cemented with ED Primer II/Panavia F 2.0, Excite DSC/Variolink II, and One-Step Plus/Duolink according to manufacturers' instructions (Groups 3, 5, and 7, respectively) or with OX during cementation (Groups 4, 6, and 8, respectively). In Group 9, inlays were cemented with a resin cement without adhesive system. After thermocycling, fracture strength was tested. The data were analyzed using two-way and one-way ANOVA and LSD post hoc tests (α = 0.05).

Results: Fracture resistance of the six groups were significantly affected by OX (p = 0.002) but not by the resin cement type (p > 0.05). The interaction of the two factors was statistically significant (p = 0.052). A statistically significant difference between all groups was found (p < 0.001). The mean fracture resistances (N) were: Gr1 = 1168 ± 157,(a) Gr2 = 360 ± 110,(d) Gr3 = 1026 ± 188,(b) Gr4 = 887 ± 143,(c) Gr5 = 1007 ± 132,(b) Gr6 = 810 ± 164,(c) Gr7 = 1033 ± 218,(a) Gr8 = 955 ± 147,(ab) Gr9 = 780 ± 86(c) (groups with the same superscript letter indicate statistical similarity).

Conclusions: Combining an OX with three resin cements had a significant negative effect on the fracture resistance of premolars restored with composite inlay cemented with Panavia F2.0 and Variolink II, but it had no significant effect when cemented with Duolink.
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http://dx.doi.org/10.1111/j.1532-849X.2012.00947.xDOI Listing
June 2013
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