Evaluating the Effect of Silver Diamine Fluoride, with or without Glutathione and Potassium Iodide, on Fluoride Release, Dentin Microhardness and Surface Properties of Dentin.

This study aimed to evaluate the effect of silver diamine fluoride (SDF) in combination with or without glutathione (Glu) and potassium iodide (KI) on the fluoride release and the enhancement of dentin microhardness. In this et al study, 90 intact premolar teeth from human subjects were allocated into nine groups, each consisting of ten samples: A) control; B) SDF; C) SDF combined with 5% Glu; D) SDF combined with 10% Glu; E) SDF combined with 20% Glu; F) KI after SDF; G) 5% Glu after SDF; H) 10% Glu after SDF; and I) 20% Glu after SDF. Data were analyzed using SPSS version 22 software and ANOVA and post-hoc and repeated measure test (P value <0.05). Dentin microhardness exhibited variations across different treatments, with the highest value being observed in the SDF-5% Glu group and the lowest in the control group. However, there was a significant difference between the mean values of SDF-5% Glu group and the SDF group. Significant increases in microhardness were observed when comparing SDF-5% Glu to SDF+5% Glu and SDF-10% Glu to SDF+10% Glu in peer groups (P value <0.05). Over time, there was a significant increase in the amount of fluoride released as compared to the initial day. The utilization of SDF-5% Glu group exhibited the most favorable effect on improving dentin hardness. Additionally, utilizing Glu in concentrations of 5% and 10% after SDF application proved more effective in increasing dentin microhardness than combining it with SDF. Moreover, in all three fluoride measurement periods, adding 5% Glu to SDF and using 20% Glu following SDF administration led to a significant increase in fluoride release compared to the application of SDF alone.

A Comparison of Laser and Mechanical Surface Pretreatment Methods on Shear Bond Strength of Resin Composite to Resin-Modified Glass Ionomer.

Statement of the Problem: Dentin margins have a higher microleakage than enamel in composite restorations due to weaker bond durability. Clinically, most margins are located apical to cementoenamel junction on the dentin or cementum. Different surface preparation methods may have dissimilar effects on the shear bond strength of resin-modified glass ionomer (RMGI) to composite resin, regarding the layering technique employed in restoration of these cavities. Purpose: This study aimed to investigate the shear bond strength of RMGI to composite resin using different mechanical surface preparation methods. Materials and Method: In this in vitro study, 72 RMGI samples were prepared in six groups (n=12): control, acid etching, air abrasion with aluminum oxide (Al2O3), bur, Er: YAG laser, and Er, Cr: YSGG laser groups. Two samples from each group were randomly examined under a scanning electron microscope (SEM). A bonding layer and composite resin were applied and cured. Then the samples were subjected to 5000-cycles thermocycling procedure. The shear bond strength was then evaluated using a universal testing machine. Finally, the failed surface of the samples was evaluated under a light microscope to examine the failure mode. For the statistical analysis, one-way ANOVA and Games-Howell post hoc test was used to compare quantitative variables and chi-squared test to investigate the relationship between the failure mode and the groups. The significant level was set at 0.05. Results: The results showed significant differences between the mean of the strength variable in the groups (p< .001). The acid-etch and air abrasion groups exhibited significantly the lowest and highest values, respectively. The chi-squared test results also showed a significant relationship between the failure mode in the study groups (p= .008). Conclusion: Acid etching before completing RMGI polymerization could adversely affect shear bond strength. The air abrasion and bur methods are among the best methods to increase the shear bond strength between composite resin and RMGI. Using Er, Cr: YSGG and Er: YAG lasers could increase the bond strength results.

Effects of at-home and in-office bleaching and three composite types (hybrid, microhybrid, and nanofilled) on repair shear bond strength of aged composites: A preliminary study.

BACKGROUND: Only a few controversial studies have assessed the repair bond strength of a fresh composite to aged composite. Moreover, no studies exist on repair bond strength of fresh composites to bleached composites. Therefore, this preliminary study was conducted to assess repair shear bond strength (SBS) of three composites bonded to nonbleached and at-home and in-office bleached composites. MATERIALS AND METHODS: In this experimental in vitro study, 108 disks (36 specimens per composite) of hybrid, microhybrid, and nanofilled composites were divided into three subgroups of three bleaching treatments: no bleaching (control), at-home bleaching, and in-office bleaching. Composite disks were incubated for 4 weeks in artificial saliva (also dipped in tea and coffee for 3 h a day). They were then thermocycled (5000 cycles). Afterward, the control group remained unbleached, while the other groups were bleached according to office and home bleaching methods. They were repaired with the same composite type. Their repair SBS and mode of failure were measured and analyzed using two-way ANOVA, Tukey, one-sample t-test, and Chi-square tests (α = 0.05, ß = 0.2). RESULTS: The mean (standard deviation) SBS values of hybrid, microhybrid, and nanofilled composites were 20.71 ± 5.99, 21.06 ± 6.68, and 9.46 ± 4.32 MPa, respectively. The mean SBS values of the bleaching techniques "home bleaching, office bleaching, and no bleaching (control)" were, respectively, 16.35 ± 7.13, 16.39 ± 8.07, and 18.49 ± 8.35 MPa. There was a significant difference among composites (two-way ANOVA P = 0.000) but not among nonbleaching/bleaching methods (P = 0.176). Their interaction was significant (P = 0.017). The difference between hybrid and microhybrid was not significant. Nevertheless, nanofilled had significantly poorer results compared to both hybrid and microhybrid composites (Tukey P = 0.000). Both hybrid and microhybrid were capable of producing satisfactory clinical repair bond strengths (above 20 MPa) regardless of bleaching or lack of it. Nanofilled composite failed to provide proper repair SBS values, even in the control (no-bleaching) group. By moving from Z100 or from Z250 to Z350, modes of failure shifted from mostly cohesive to mostly adhesive (P < 0.05). CONCLUSION: Bleaching of an aged composite might not affect the repair bond strength. Hybrid and microhybrid composites can provide clinically acceptable repair bond strengths, regardless of bleaching. Nonetheless, nanofilled composite is inferior to them and cannot provide appropriate repair bond strengths (regardless of bleaching).

Evaluation of shear bond strength of zirconia to composite resin using different adhesive systems.

BACKGROUND: To evaluate shear bond strength of zirconia to composite resin using different universal and conventional adhesives and a zirconia primer. MATERIAL AND METHODS: Forty zirconia blocks were fabricated of zirconium ingots (10×10×5 mm) and sintered at 1530°C for 2 hours. They were then air-abraded with Al2O3 particles. The specimens were divided into 4 groups and subjected to one of the following bonding agents: Futurabond U (group 1), Clearfil Universal Bond, universal adhesives (group 2), Z-Prime Plus, zirconia primer (group 3) and Adper Single Bond 2, conventional adhesive (group 4). Composite resin was then applied in a diameter of 5 mm and in a thickness of 2 mm. All the specimens were stored in distilled water at 37°C for 24 hours and then thermocycled between 5°C and 55°C for 5000 cycles with a 30-second dwell time. The shear bond strength was then evaluated with a universal testing machine at a crosshead speed of 1 mm/min. Data (MPa) were analyzed using ANOVA and LSD test (P≤0.05). The specimens were evaluated under a stereomicroscope to determine the mode of failure. RESULTS: The mean shear bond strength was 16,874 MPa in group I, 13.4434 MPa in group II, 11.6500 MPa in group III and 6.8700 MPa in group IV. ANOVA revealed that the shear bond strength in group IV was significantly lower than that in other groups (P≤0.05). CONCLUSIONS: The shear bond strength in group I was significantly higher than that in groups III and IV. So Universal adhesives could provide higher shear bond strength of zirconia to composite resin after thermocycling compared to zirconia primers. Key words:10-MDP, shear bond strength, universal adhesive systems, zirconia primer.

Frequency and Pattern of IgE-mediated Sensitization to Aero and Food Allergens in Ahvaz, Province of Khuzestan in Southwestern Iran.

Efficient diagnosis of allergy and proper treatment need identification of the causative allergens eliciting clinical symptoms. The present study was performed to identify the most common aero- and food allergens and determine the pattern of sensitization among people of Ahvaz (southwestern Iran), one of the most polluted cities worldwide. Based on the physical examination and medical records, patients were referred to the Allergy laboratory for "in vitro" IgE determination. Specific and total IgE was determined by the ImmunoCAP system (Thermo Fisher-Phadia, Uppsala, Sweden). A total of 666 consecutive patients (51.1% female) were tested for 202 different allergens. The majority of requests (57%) belonged to food allergens. Sensitization to at least one allergen was found in 47.6% of patients. In a selected group of allergens for which specific IgE had been tested in at least 100 patients, the most common sensitizing aeroallergens were Russian thistle, grass pollen, and willow; while wheat, honey, and shrimp were the most frequent food allergens, respectively. Sensitization profiles based on measurement of specific IgE indicated that Russian thistle, grasses, and wheat were the most prevalent allergens in people with allergic symptoms living in Ahvaz.

Evaluation of microleakage of class II dental composite resin restorations cured with LED or QTH dental curing light; Blind, Cluster Randomized, In vitro cross sectional study.

BACKGROUND: The aim of this study is to compare the microleakage of Class II dental composite resin restorations which have been cured by three different LED (light emitting diode) light curing modes compared to control samples cured by QTH (quartz tungsten halogen) light curing units (LCUs), to determine the most effective light curing unit and mode of curing. RESULTS: In this experimental study, class II cavities were prepared on 100 sound human premolars which have been extracted for orthodontic treatment. The teeth were randomly divided into four groups; three experimental and one control group of 25 teeth each. Experimental groups were cured by either conventional, pulse-delay, or ramped curing modes of LED. The control group was cured for 20 seconds by QTH. The restorations were thermocycled (1000 times, between 5 and 55°C, for 5 seconds dwell time), dyed, sectioned mesio-distally and viewed under stereo-microscope (40×) magnification. Teeth were then scored on a 0 to 4 scale based on the amount of microleakage. The data were analyzed by Chi-square test.No significant difference was demonstrated between the different LCUs (light curing units), or modes of curing, at the enamel side (p > 0.05). At the dentin side, all modes of LED curing could significantly reduce microleakage (p < 0.05). The results suggest that slow start curing improves marginal integrity and seal. High intense curing endangers those aims. CONCLUSIONS: Comparison between the three LED mode cured composite resin restorations and QTH curing showed LED curing in all modes is more effective than QTH for reducing microleakage. Both LED and QTH almost completely eliminate the microleakage on the enamel side, however none of them absolutely eliminated microleakage on the dentin side.

The association between hyperlipidemia and periodontal infection.

BACKGROUND: Periodontitis is a local chronic inflammatory condition of the supporting structures of the teeth resulting from a dental plaque biofilm attached to teeth surfaces. Recent studies have indicated that this oral disease may have effects on systemic health. OBJECTIVES: The aim of the present study was to evaluate the association between periodontitis and hyperlipidemia. PATIENTS AND METHODS: This case-control study was conducted in Iran during March 2011. In this case-control study, levels of serum lipids in 45 subjects with periodontitis were measured and compared with 45 age, gender and body mass index (BMI) matched controls. Data were analyzed using student t-test and chi-square test with P < 0.05 as the limit of significance. RESULTS: Mean values of total cholesterol (CHL) (periodontitis group = 218.11 ± 29.77, control group = 162.31 ± 48.24) and triglycerides (TG) (periodontitis group = 209.77 ± 44.30, control group = 125.60 ± 44.16) were significantly higher in the periodontitis group (P < 0.001). High-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol levels were higher in the case group, but this difference was not statistically significant. Frequency of pathological values of CHL and TG were significantly higher in cases compared with the controls (P = 0.002 and P = 0.015, respectively). CONCLUSIONS: This study indicates that hyperlipidemia may be associated with periodontal disease in healthy individuals; yet whether periodontitis causes an increase in levels of plasma lipids or whether hyperlipidemia is a risk factor for periodontal infection and cardiovascular disease, it needs further investigations.

Antibacterial Effect of Juglans Regia Bark against Oral Pathologic Bacteria.

Background. In this study antimicrobial effect of ethanolic and aqueous extracts of Juglans regia bark in Iran was evaluated on four different oral bacteria, Streptococcus mutans, Streptococcus salivarius, Streptococcus sanguis, and Staphylococcus aureus. Methods. Aqueous and ethanol extracts of Juglans regia bark were prepared by using disk diffusion technique and Minimal Inhibitory Concentration (MIC) methods. Tetracycline 30 µ g and Erythromycin 15 µ g were used as positive control and water as negative control in disk diffusion and MIC methods. Data were analyzed by ANOVA test. Results. The results showed that S. sanguis and S. mutans were the most sensitive and the most resistant bacteria against ethanolic and aqueous extracts, respectively. Ethanolic extract had significant antibacterial effect against all tested bacteria. Aqueous extract did not show antibacterial effect on S. mutans, in contrast to ethanolic extract. Aqueous extract had significantly antibacterial effect against Staphylococcus aureus, S. salivarius, and S. sanguis compared to control (P < 0.0001), but it did not show effect on S. mutans when compared with Erythromycin. According to the obtained MIC values, ethanol extract of Juglans regia bark had the lowest rate. Conclusion. The results may provide the basis for using natural antimicrobial substance for oral hygiene prophylaxis purposes.