Pinar Gul

HPLC ANALYSIS OF ELUTED MONOMERS FROM DENTAL COMPOSITE USING DIFFERENT IMMERSION MEDIA

Numerous factors may play a role in the monomer release of dental materials. The aim of this study is to measure the release of monomers from commercially available hybrid composite resin Tetric Ceram (Ivoclar Vivadent AG, Schaan, Liechtenstein) in the following time schedule, 1 hr, 24 hr, 7 d, and 30 d after the polymerization and observation of the effects of different immersion media on released monomers. Twelve specimen discs were prepared using hybrid composite resin for each analyte in three media [ethanol/water solution (75:25, v/v), distilled water, artificial saliva]. The High Performance Liquid Chromatography (HPLC) method was used for the analysis of released monomers from the hybrid composite resin. All monomers were released in ethanol/water solution with higher efficiency than the other two media, and the highest amount of release was obtained from BisGMA (p < 0.001). Ethanol/water solution which is suggested to simulate the environment of the mouth is the most effective media for monomer release from composite resins.

Comparison of the translucency of two multishaded composite resins polymerized with direct or indirect method

Abstract The aim of this study was to measure the translucency of one indirect and direct resin composite after polymerization and to examine the effect of color parameters on this property. Tescera and Filtek Ultimate, each containing three shade groups (Enamel, Dentin and Body for Filtek Ultimate; and Incisal, Opaceous Dentin and Body for Tescera), were investigated. The translucency parameter (TP) was measured as the color difference between a specimen over a white and black background. Significant differences were observed in TP values between shade groups. Tukey’s multiple comparison test revealed TP values among the groups of Filtek Ultimate-Enamel > Tescera-Incisal > Filtek Ultimate-Body > Tescera-Body = Filtek Ultimate-Dentin > Tescera-Opaceous Dentin. In conclusion, it is concluded that the translucency of resin composite was affected by polymerization and color parameters.

Anticariogenic potential of white cheese, xylitol chewing gum, and black tea

Objective: This study aimed to examine the effects of these foods on plaque pH and the potential development of tooth decay. Materials and Methods: Plaque pH was measured using the sampling method before and after 1, 5, 10, 20, 30, 45, and 60 min following consumption of these foods individually and after rinsing with a 10% sucrose solution. Statistical analysis was performed using one-way ANOVA and Tukey honestly significant difference post hoc tests (α = 0.05). Results: Although there were statistically significant differences in all test groups except the BT (P = 0.620) and sucrose + XCG (P = 0.550) groups in time, none of the participants chosen for this study were having a plaque pH value anywhere close to the critical value (pH = 5.5). Conclusion: WC, BT, and XCG are advisable as anticariogenic foods because pH values are not below critical value.

Lipid peroxidation and DNA oxidation caused by dental filling materials

Background/purpose The two direct dental restorative materials most commonly used today are silver-mercury amalgam and resin-based composites. The purpose of this study was to examine the effects of these two restorative materials and substances released by these into the oral environment on lipid peroxidation and DNA oxidation after entering the blood circulation. Materials and methods Blood samples from 41 patients were collected before and 24 hours after the application of these restorative materials. The 8-hydroxydeoxyguanosine/deoxyguanosine ratio in these samples was measured to determine oxidative DNA damage, and malondialdehyde levels were measured to define lipid peroxidation. The paired samples t test and Pearson correlation analysis were used for the analysis of variables (α = 0.05). Results While no statistically significant difference was observed after amalgam filling application in terms of DNA oxidation, a significant difference was observed after composite application (P < 0.05). Furthermore, a significant increase was determined in malondialdehyde levels of two materials (P < 0.05). In both amalgam and composite applications, a significant difference was observed before and after application in terms of released substances (mercury and unpolymerized monomer, respectively, P < 0.001). Conclusion Mercury increased lipid peroxidation and Bis-GMA and TEGDMA dental resins increased both lipid peroxidation and DNA oxidation markers.

Comparison of radiopacity of different composite resins

Background: The radiopacity of composite resins has been considered as an important requirement, improving the radiographic diagnosis. Aim: The present study aimed to compare the radiopacity of eight different composite materials using an aluminum step wedge. Materials and Methods: Eight different composite resins were used in this study. The samples were prepared using a stainless steel mold (2 × 8), and a 2-mm-thickness horizontal section was obtained from the freshly extracted molar tooth. Three different radiographs were taken by establishing standard conditions. Mean gray values were obtained by taking three measurements from each step of both the tooth and the aluminum step wedge, and the aluminum thickness equivalents were calculated. Statistical analysis was performed using one-way variance analysis and Tukeys test (P < 0.05). Results: All aluminum thickness equivalents were found to be higher than those of the enamel and dentin, except Clearfil Majesty Esthetic (2.23 mm ± 0.52 mm) and Filtek Silorane (3.67 mm ± 0.15 mm) (P < 0.05). The Clearfil Majesty Posterior (8.50 mm ± 0.10 mm) and Arabesk Top (8.17 mm ± 0.06 mm) were found to be the most radiopaque composites. Conclusion: All composite resin materials tested in this study were confirmed to the International Standards Organization 4049 standards. However, since radiopacity is not the only criterion for clinical use, it is a better approach to take all other properties of the materials into consideration.

Effect of different bleaching applications on the surface properties and staining susceptibility of dental composites

The aim of this study was to investigate the effects of two bleaching systems on micro hardness, surface roughness and color stability of two novel dental composites. Ormocer based restorative Admira and nano-filled composite Clearfil Majesty Esthetic were bleached with 10% carbamide peroxide (Opalescence PF) or 35% hydrogen peroxide (Beyond Max 5) and subsequently immersed in four different staining solutions (coffee, tea, red wine, and cola). Distilled water was used as a control. Color measurements were performed with a spectrophotometer. Vickers micro hardness and roughness data were analyzed with two-way analysis of variance for repeated measures. The analysis of variance was used to compare the color change values. Duncan’s multiple comparison test was applied to compare the results (α = 5%). ΔEab* values over 3.3 were considered clinically unacceptable. Micro hardness and surface roughness values of the tested composites were decreased significantly after bleaching applications. Red wine and tea storage caused perceptible discolorations in the composite resin materials after 30 days of 3-hour immersion. Home or office bleaching applications can affect the surface properties of resin composites and accelerate the staining process.

Quantification and identification of components released from dental composites using different chromatographic techniques

ABSTRACT This study aimed to review recent chromatographic methods for quantifying and identifying components released from dental composites. Resin-based dental restorative materials are extensively used in dentistry today. Although composite materials are known to be highly stable structures, they are susceptible to degradation because of the incomplete polymerization. Several components may be released from resin composite restorations into the oral environment. The elution of components from composite resins may affect the biocompatibility of the restorations. Therefore, it is essential to understand the nature and quantity of substances that are segregated into the oral cavity. GRAPHICAL ABSTRACT

Effects of composite restorations on nitric oxide and uric acid levels in saliva

Background and Aims: Dental materials that are used in dentistry should be harmless to oral tissues, and should, therefore, not contain any leachable toxic and diffusible substances capable of causing side effects. This study was intended to investigate the effects on salivary nitric oxide (NO) and uric acid (UA) levels after application of dental composite filling materials to healthy volunteers. Materials and Methods: A total of 52 individuals (32 female and 20 male) participated in the study. Filtek Z250 composite filling material (3M ESPE, St Paul, MN, USA) was applied to healthy volunteers. Saliva samples were collected before restoration (baseline) and 1 h, 1-day, 7 days, and 30 days after restoration. NO concentrations were measured using the Griess reaction method, and UA was measured using an enzymatic method. Data were analyzed using repeated measures ANOVA and the Bonferroni post-hoc test (α =5%). Results: NO values increased statistically significant after 7 days (P < 0.05). In addition, lower UA levels were determined compared to the baseline levels, but the difference was not statistically significant (P > 0.05). There was no correlation between NO and UA levels in saliva (P > 0.05). Conclusion: Composite resins activated the antioxidant system in saliva. However, further studies are now needed to confirm our findings and to permit a definitive conclusion.