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Dental Materials and Techniques - Volume:5 Issue: 1, Winter 2016

Journal of Dental Materials and Techniques
Volume:5 Issue: 1, Winter 2016

  • تاریخ انتشار: 1394/10/14
  • تعداد عناوین: 8
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  • P.C. Pott, M. Stiesch, M. Eisenburger Pages 1-10
    Introduction
    This in-vitro study investigates the bond strength of different zirconia composites with three different modern adhesive systems after artificial aging using thermocycling and water storage.
    Methods
    A total of 90 specimens of zirconia (InCoris, Sirona, Germany, Bernsheim) were ground using a 165 µm grit rotating diamond disc. Thirty specimens were additionally treated with either Futurabond U “FBU” (VOCO GmbH), or Futurabond M+ “FBM” (VOCO GmbH) or Futurabond M+ in combination with the DCA activator “FBMD” (VOCO GmbH). One of the three different types of composites – BifixSE “BS”, BifixQM “BQ” or GrandioSO “G” (VOCO GmbH) – was bonded to the ten specimens of each group. All of the specimens underwent artificial aging using thermocycling between 5°C and 55°C for 5000 cycles followed by water storage for 100 days. Shear bond strength (SBS) was determined in a universal testing machine. The type of failure was evaluated using fluorescence microscopy. The data were compared to existing data without artificial aging. Statistical analysis was performed with ANOVA and the Tukey test.
    Results
    FBM and FBMD had higher SBS than FBU in combination with all tested composites, except BifixSE. In nearly all groups, artificial aging had no effect, with the exception of the combination of FBMD with BifixSE, in which there was a significant decrease in SBS after the aging process (p<0.001).
    Conclusion
    The new 10-MDP-containing adhesive systems including FBU, FBM and FBMD are insensitive to the aging process tested in this study.
    Keywords: zirconia, 10 MDP, containing primer, composite resin, artificial aging
  • Masoumeh Khoshhal, Fariborz Vafaee, Sahar Raisi Pages 11-16
    Introduction
    Introduction
    Few studies have investigated the distribution of stress around implants. In this study the distribution of stress in bones around implants was investigated in five overdenture (OD) treatment designs including OD-1, OD-2, OD-3, OD-4 and OD-5.
    Materials And Methods
    The Catia modeling software was used in order to simulate the tooth/implant model and bone. First, the borders of cancellous and cortical bone in each section of the CT images were attained by Photoshop software. Then, modeling softwares SolidWorks and NUMBER were applied to make the final three-dimensional model of jaw. Finally, the amount of stress on the surface of bone/implant was studied by means of stress analysis software (Ansys v11.0).
    Results
    Protrusive movements of implants B and D in OD-1 showed the highest amount of strain, 2435 εµ. Also, high amounts of strain, 1668 and 1557 εµwere observed in OD-1 and OD-2 designs in lateral movements respectively.
    Conclusion
    The bottom line is that no forces to the extent of destruction based on the Ferost model were found for these designs. The highest amount of strain occurred in OD-1 design, which is held in mild overload window. Moreover, the amounts of strain in the rest of designs investigated were in adaptive window.
    Keywords: Dental implant, stress distribution, overdenture, Frost model
  • Mitra Tabari, Samane Gharekhani, Behnaz Esmaeili, Arash Poorsattar Bejeh Mir, Mobina Mollaei, Mona Alimohammadi, Mahmood Haji Ahmadi Pages 17-22
    Introduction
    In recent dentin adhesive systems etching of enamel/dentin are achieved simultaneously. The objective was to evaluate the microleakage of composite restorations using Single Bond2 (5th generation), Clearfil S3 Bond and G Bond (7th generation).
    Methods
    Class V cavities were prepared on 45 extracted intact premolars with gingival margins at the cementoenamel junction and they were randomly divided into 3 groups (n=15) based on the type of adhesives: Single Bond2 (5th generation), Clearfil S3 Bond and G Bond (7th generation). After applying the adhesives, the cavities were filled with Z250 composite resin. The occlusal and gingival microleakage was evaluated using 2% basic fuchsin staining technique. Data were analyzed using Kruskal-Wallis and Bonferroni corrected Mann-Whitney U tests.
    Results
    The mean rank of occlusal microleakage exhibited significant differences by comparison of G Bond, Clearfil S3 Bond and Single Bond2 (21.07, 30.67) and 17.27, respectively) (P=0.005). There was a significant difference in gingival microleakage of different bonding agents (34.40, 17.83 and 16.77 for G Bond, Clearfil S3 Bond and Single Bond2, respectively) (P<0.001). There was a significant difference in occlusal microleakage of Clearfil S3 Bond and Single Bond2 (P= 0.003), but no significant difference was found between Clearfil S3 Bond and G Bond (P=0.025). No significant difference was observed between occlusal microleakage by G Bond and Single Bond2 (P=0.238). The difference in gingival microleakage was significant by G Bond compare with Single Bond2 and Clearfil S3 Bond (P<0.001and P<0.001, respectively).
    Conclusion
    The microleakage of class V composite restorations in permanent teeth using the Single Bond2 was lower than that with the use of G Bond in gingival margins. The sealing ability with Single Bond2 was superior to Clearfil S3 Bond in occlusal margin but they were equally effective at gingival margin.
    Keywords: words: Bonding agent, composite resin, Dentin, Enamel, Microleakage
  • Ahmad Ghahremanloo, Mohsen Movahedzadeh Pages 23-30
    Introduction
    Denture stomatitis is a common complication in patients wearing dentures and preventing the proliferation of related microorganisms and their induced infections is noteworthy. The aim of the present study was to assess the antimicrobial effect of acrylic resins containing various concentrations of silver nanoparticles, on Candida albicans and Streptococcus mutans.
    Materials And Methods
    In this in vitro study, the effect of four different concentrations of silver nanoparticles in 160 acrylic samples (10mm *4mm) on standard and hospital isolated strains of two different microorganisms were investigated. The samples were soaked (containing silver nanoparticles and control) in bacterial suspension and the antimicrobial tests were performed after 0, 1, 6 and 24 hours. Mean and standard deviation were used to describe the data and one-way variance analysis test was performed to compare groups.
    Results
    Results have shown that in concentration of 2.5% the highest mean difference for standard S. mutans, after 24h of exposure was 540.0±14.4 (P<0.001), while in 5%, this value for standard C.albicans after 6h of exposure was 953.0±87.0 (P<0.001). However in concentration of 10% the highest mean difference of 1000.0±24.9 in standard C.albicans after an exposure period of 24h (p<0.001) was observed, which was indicative of the significant effect of the highest concentration of silver nanoparticles.
    Conclusion
    1. in acrylic resins, increase in silver nanoparticle concentration leads to a greater antimicrobial effect. 2. Acrylic resins containing silver nanoparticles have a stronger antimicrobial property on standard C.albicans and generally less effect on hospital isolated strains. 3. The longer time elapsed after exposure of bacterial suspension with acrylic resins containing silver nanoparticles, the less the residual antimicrobial effect.
    Keywords: Silver nanoparticles, Acrylic resins, Antimicrobial effect
  • Naser Sargolzaie, Omid Rajabi, Hamidraza Arab, Habibollah Esmaele, Atefeh Ehteshamfar Pages 31-35
    Introduction
    Nowadays in the field of dentistry, there is a trend to encourage the use of herbal and natural products. The high level of clinical research in terms of considering green tea and aloe vera, with various functionality for individual use is a typical example. The purpose of this randomized, controlled, and double-blind study was to evaluate comparative evaluation of green tea-aloe vera mouthwash and chlorhexidine 0.2% on gingival indices.
    Methods
    A total of 60 patients (26 women and 34 men) with periodontal disease were randomly allocated into one of the three double blind groups, 20 in each, to receive the following treatments: (1) 0.2% chlorhexidine, (2) green tea-aloe vera and (3) distilled water. Plaque and gingival indices were evaluated on the day of the beginning of the experiment and 14 days postoperative. Subjects were asked to rinse their mouth with the mouth rinse, twice a day, during a 14-day period. Paired t-test was used to test the mean difference on 0 and 14 days, respectively. One way analysis of variance (ANOVA) was used to compare the mean difference between the groups while Tukey test was used for multiple comparisons.
    Results
    Chlorhexidine 0.2%, green tea - aloe vera and placebo reduced the plaque index by 0.17±0.14, 0.10±0/08 and 0.02±0.18, respectively, with a statistical significance of p=0.008. This difference was related to Chlorhexidine 0.2% and green tea - aloe vera with Placebo. There exist a significant difference of p=0.001 in the bleeding index between the three groups, and this difference was related to Chlorhexidine 0.2% and green tea - aloe vera with placebo.
    Conclusion
    Green tea –aloe vera mouthwash improves periodontal health status. Therefore, it can be used to improve oral and dental health status.
    Keywords: Green tea, Aloe Vera mouthwash, chlorhexidine mouthwash, dental plaque
  • Shaghayegh Razavi, Gazaleh Ahmadizenouz, Hemmat Gholinia, Mohammad Jafari Pages 36-42
    Objectives
    The aim of this study was to evaluate the effect of four commercially available mouthrinses on the color stability of one type of glass ionomer, giomer and compomer.
    Method
    60 disc-shaped specimens, 180 in total (7*2mm), fabricated from each of the following materials: A resin modified glass ionomer Fuji II LC (GC International Corp), a giomer Beautifil II (SHOFU INC) and a compomer Ionosit (DMG). All specimens were stored in artificial saliva at 37˚C for 24 hours in an incubator. The initial colour value (L*,a*,b*) were recorded with spectrophotometer according to CIELAB scale. After baseline evaluation, the specimens were divided into five subgroups, according to the testing and control storage solutions (n=12). Randomly selected specimens from each material were immersed in 20 ml of the treatment solutions (Oral-B Pro Expert, Listerine, Colgate Plax, Irasha) at 37˚c for 24 hours. Each specimen was then subjected to second color measurement. The collected data was statistically analyzed using two-way analysis of variance (ANOVA) and Tukey’s HSD at a significance level of 0.05.
    Results
    All samples displayed color changes after immersion in the mouthrinses. The observed color difference showed that mouthrinses have a significant effect on the color shift of tested materials. A significant interaction was found between the materials and the mouthrinses. Overall, discoloration with all mouthrinses was significant when compared to the control specimens stored in artificial saliva. Oral-B induced the highest level of discoloration (ΔE*= 11.62 in Compomer) and the least discoloration was found with Irsha (ΔE*= 1.47 in RMGI).
    Conclusions
    All tested restorative materials showed a color shift after immersion in mouthrinses, amongst which compomer displayed the highest change. Discolorations were clinically perceptible in most of the cases. Thus it can be concluded that daily use of mouthrinses increases the stainability of tested materials.
    Keywords: artificial saliva, bracket, galvanic corrosion, orthodontic archwire
  • Amir Moeintaghavi, Habibollah Ghanbari, Mehrdad Radvar, Reza Zare, Naser Sargolzaei, Hamed Nicknam Pages 43-48
    Background And Aim
    Although there have been substantial developments in dental implant therapies, achieving good implant stability (ISQ >60) for implants inserted in augmented sinus sites appears to be challenging in comparison with non-augmented sites due to the high prevalence of bone resorption in posterior regions of maxilla. This study aimed to evaluate and compare the time required to achieve good implant stability between implants inserted in sites that had undergone a sinus augmentation procedure with implants inserted in non-augmented similar regions of maxilla.
    Methods
    Thirty Stroman ITI Dental Implants were inserted in 14 patients (8 females and 6 males) with average age of 55 ± 10 years. Fourteen implants were inserted in sinus augmented sites (open sinus elevation and Demineralized Freezed Bone Allograft or DFDBA) 6 months after healing (test group), and 16 implants were inserted into non-augmented posterior areas of maxilla (control group). The implant stability quotient (ISQ) for each implant was measured at the time of insertion (baseline, ISQ0) and at 1, 2 and 3 months later (ISQ1, ISQ2, ISQ3). Residual and augmented bone heights were also recorded.
    Results
    The average residual bone height was 2.92 ± 0.63mm and 10.41 ± 1.46mm for the augmented bone height. The difference between ISQ values in the test and control groups was only significant at the baseline (p=0.023). No significant correlation was found between ISQ and bone height (residual and augmented), and there was no significant correlation between ISQ values and the implant diameter and length. In the test group, the differences between ISQ0 and ISQ1, ISQ1 and ISQ3 and ISQ2 and ISQ3 were all statistically significant (p=0.006, p=0.032, p=0.046). In the control group, the difference was only significant between ISQ0 and ISQ1 (p=0.002).
    Conclusion
    ISQ values were not statistically significant between implants inserted in natural and augmented bone six months after sinus augmentation. In other words, within the limitation of this study, the time required to achieve good stability for implants inserted in augmented sinus sites is similar to those inserted in non-augmented sites.
    Keywords: ISQ, sinus lift, Implant stability
  • Masoomeh Afsa, Asma Zangizade, Ghader Zargaran Pages 49-52
    Objectives
    In restorative dentistry, it is essential to estimate the amount of remnant tooth structure after caries removal to make the best treatment plan. The present study was aimed to determine whether there is a correlation between the real thickness of remnant dentin under carious lesion and the radiographical measurement from photostimulable phosphor plates (PSPs).
    Methods
    a whole number of 68 unrestored permanent human molar and premolar teeth with 82 proximal carious surfaces were mounted in an artificial arch. Digital bitewing radiographs with PSPs were taken, carious lesions were removed and radiographic imaging was repeated. Teeth were sectioned mesiodistally in two parts and thickness of remnant tooth structure to pulp was measured. Measurements of remnant dentin under caries from radiographic images and teeth structures were compared.
    Result
    The mean measurements of remnant dentin on primary radiographs were statistically different from the measurements on teeth structures. The mean thickness of remnant dentin on tooth structure was around 30% less than what measured on radiographic image.
    Conclusion
    The real thickness of remnant dentin under caries is about 70% of its thickness measured on digital bitewing radiographs prepared by PSPs as image receptor.
    Keywords: Caries, Bitewing, Radiography