Evaluation of the changes in physical properties and mineral content of enamel exposed to radiation after treating with remineralization agent.

OBJECTIVE: The aim of this study was to investigate the effect of different remineralization agents on the physical properties and elemental content of enamel exposed to radiation. MATERIAL AND METHOD: The enamel surfaces of impacted third molar teeth were prepared, and six study groups were created (n = 6). Next, 60 Gy radiation was applied to each group. Between applications, each group except for the control group was treated with a different remineralization agent (sodium fluoride, casein phosphopeptide-amorphous calcium phosphate (CPP-ACP), casein phosphopeptide amorphous calcium phosphate with fluorite (CPP-ACFP), bioactive glass, or chitosan). The results were evaluated in terms of pre- and post-radiation values and the difference between the two. The paired-samples t test and analysis of variance test were used in the analysis of normally distributed hardness and roughness values, while Wilcoxon's signed ranks test, and the Kruskal Wallis and Mann-Whitney U tests were used in the analysis of elemental content without normal distribution. RESULTS: A statistically significant decrease was observed in microhardness measurements in all groups. Intragroup evaluation revealed a statistically significant difference between the NaF and bioactive glass groups (p < 0.05). No significant difference was observed between the groups' roughness measurements (p < 0.05). Intergroup evaluation of surface roughness revealed a significant difference in the CPP-ACFP and chitosan groups (p < 0.05). Pre- and post-radiation oxygen, magnesium, and potassium levels and Ca/P ratios also differed significantly (p < 0.05). CONCLUSION: Radiation caused a statistically significant difference in the microhardness and elemental content of enamel. However, no significant difference was observed in enamel roughness. The applied remineralizing agents have a partial ameliorating effect on the adverse impacts of radiation. CLINICAL RELEVANCE: Radiation causes changes in the mechanical properties and elemental content of tooth enamel. Remineralizing agent application is a promising option in reducing the adverse effects of irradiation.

Effect of staining and bleaching on the microhardness, surface roughness and color of different composite resins.

BACKGROUND: There are studies that examined the effect of staining on the surface properties of composite resins, using different solutions and bleaching applications. However, the effect of both staining and bleaching on the same composite specimens is an issue that needs to be investigated. OBJECTIVES: The aim of this study was to investigate the surface microhardness, roughness and color changes (ΔE) of 2 different composite resins after staining and bleaching. MATERIAL AND METHODS: A microhybrid and a nanohybrid composite were used in the study. One hundred and fifty specimens were prepared from each composite. The specimens were divided into 5 groups and stained for 30 days with tea, coffee, cola, red wine, or distilled water (control). Subsequently, each group was divided into 3 subgroups. Each subgroup received a 14-day application of Opalescence™ Boost, Opalescence PF or VivaStyle® Paint On Plus bleaching materials. The color as well as surface microhardness and roughness of all specimens were determined at baseline, after staining and after bleaching. Data was analyzed using the repeated-measures analysis of variance (ANOVA) and the Bonferroni method. RESULTS: A statistically significant decrease was observed in the surface microhardness of the microhybrid composite specimens after bleaching (p < 0.05).The highest ΔE values were observed in the red wine groups for both composite resins. CONCLUSIONS: Staining and bleaching may affect surface properties and color, depending on the type, filler and matrix content of the composite resin.

Effects of Bisphenol A Released From Composite Fillings on Reproductive Hormone Levels in Men.

OBJECTIVES: Composite resins are the most preferred filling material because of their excellent aesthetic qualities. However, a filling material should also be biocompatible as well as aesthetic. The aim of this study was to determine the serum and saliva bisphenol-A (BPA) levels and to examine the effects of serum BPA on reproductive hormone levels after healthy men were treated with composite fillings. METHODS: Eighteen healthy males each received 2 composite restorations. Saliva and blood samples of subjects were collected before resin application and 1 day and 1, 3, and 5 weeks after the resin was applied. BPA amounts in samples were detected using high-performance liquid chromatography (HPLC). Serum gonadotropins, testosterone, sex hormone binding globulin, free androgen index, and oestrogen levels were measured with radioimmunological assay kits. Statistical analysis of data was made using Friedman, Wilcoxon signed ranks and Mann-Whitney U tests (α = 0.05). RESULTS: The amount of BPA released from composite resins over time was not significantly elevated in either saliva or serum (P > 0.5). In addition, serum BPA levels were significantly higher than saliva BPA levels for both composites (P < .05), but saliva and serum BPA levels were not statistically different when comparing the 2 composites (P > .05). CONCLUSIONS: BPA from composite resins used in this study did not significantly alter serum hormone levels.

The cytotoxic and oxidative effects of restorative materials in cultured human gingival fibroblasts.

The aim of this study was to evaluate the cytotoxic and oxidative effects of the most commonly used dental restorative materials on human gingival fibroblast cells (HGFCs). HGFCs were obtained from healthy individuals. The tested restorative materials were a microhybrid resin based composite, a compomer resin, a glass ionomer cement, and an amalgam alloy. One hundred eight cylindirical samples, 10 mm in diameter and 2 mm in height, were prepared according to ISO 10993-12:2002 specifications (n = 9 in the tested subgroups). Freshly prepared and aged samples in artificial saliva at 37 °C (7 and 21 d) were placed into well plates and incubated. Wells without dental materials were constituted as the control group. After 72 h incubation period, cytotoxicity was determined using the neutral red (NR) assay. Oxidative alterations were assessed using total antioxidant capacity (TAC) and total oxidant status (TOS) assay kits. Data were analyzed using the ANOVA and LSD post hoc tests. All tested materials led to significant decreases in the cell viability rates (33-73%) compared to the control group. Glass ionomer and resin composite were found to be more cytotoxic than amalgam alloy and compomer. The highest TAC level was observed in glass ionomer after seven-day aging and these changes prevented an increase in TOS levels. Increases in TAC levels after seven-day aging in all groups exhibited significant differences with freshly prepared samples (p < 0.05). In all material groups, TOS levels of freshly prepared samples differed statistically and significantly from samples aged for 7 and 21 d (p < 0.05). The data obtained suggested that all the tested materials exhibited cytotoxic and pro-oxidant features. Freshly prepared samples caused higher TOS levels. However, oxidant status induced by materials decreased over time.

Effect of fiber reinforcement on color stability of composite resins.

AIM: The aim of this in vitro study was to determine the effect of fiber reinforcement on the color changes of two different composite resins. MATERIALS AND METHODS: A silorane-based composite (Filtek Silorane, A2 shade) and a methacrylate-based composite (Valux Plus, A2 shade) were used in this study. Three groups of samples (control group with no reinforcements, polyethylene fiber [Ribbond THM]-reinforced composite, and glass fiber [everStick® Net]-reinforced composite groups) were prepared from each composite (n = 8). The color change was calculated between baseline and 1 day (ΔE1) and between baseline, 7 days (ΔE2), and 21 days (ΔE3) with a spectrophotometer. The data were analyzed by ANOVA, Duncan's multiple-range tests and independent sample t-test. RESULTS: Statistical analysis of variance presented the statistically significance difference between composite, fiber, and time for ΔE (P < 0.05). The Ribbond reinforced composite showed a similar color change to the control group (ΔE = 3.69), while the everStick reinforced composite showed the largest total color change (ΔE = 4.13). It was determined that the time is an effective factor on the color stability of reinforced composites (P < 0.05). CONCLUSION: The addition of fiber may lead to color change in composite resins. The amount of change may differ depending on the structural properties of the composite resin or the fiber and time.

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.

The Effect of Polymerization and Preparation Techniques on the Microleakage of Composite Laminate Veneers.

BACKGROUND: Marginal leakage is the important factor influencing the maintenance of dental esthetic. AIM: The purpose of this study was to evaluate the relationship between the preparation techniques and type of polymerization techniques on microleakage of composite laminate veneers. MATERIALS AND METHODS: Ninety-one same sized, caries-free human maxillary central incisors were randomly assigned to 13 groups (n = 7) and were designed with four different preparation techniques (window type, feather type, bevel type, and incisal overlap type). One group determined as control group and any preparation was applied. Nanohybrid resin composite was used for restoration. Composite laminate veneers polymerized with three different techniques (direct light curing, indirect polymerization with a combination of pressure, light and heat using a light cup and heat cup, direct polymerization, and additionally heat cured in an oven). The specimens were thermocycled, and then immersed in 5% basic fuchsine solution. Following 24 h, all specimens were immersed in 65% nitric acid solutions for volumetric dye extraction test. Samples diluted with distilled water and centrifuged and microleakage determined by a spectrophotometer. STATISTICAL ANALYSIS USED: Data were analyzed with two-way ANOVA and Tukey honest significant difference post hoc multiple comparisons test (P < 0.05). RESULTS: For comparing the microleakage value of preparation and polymerization techniques, Window type preparation showed a significant difference in direct polymerization + additional cured group (P < 0.05). Control group was statistically different from the other groups (P < 0.05). CONCLUSIONS: Window type laminate preparation can be preferred in indirect polymerization technique because it caused less leakage in this present study.

The effect of restorative materials on cytokines in gingival crevicular fluid.

OBJECTIVE: Composition of the restorative materials may cause inflammatory responses by monocyte activation and changes in the levels of cytokine released from different cells. Interleukin-6 (IL-6), interleukin-8 (IL-8) and Tumor necrosis factor alpha (TNF-α) are important cytokine for evaluating of the inflammatory process. The aim of this study was to evaluate the different restorative materials used in class V cavities effect on gingival crevicular fluid inflammatory cytokine levels. DESIGN: 60 individuals having Class V carious cavities participated in the study. Cavities were restored with FiltekZ250, DyractXP, Fuji IX, Cavex avalloy restorative materials. Changes in clinical and biochemical parameters were evaluated before restorations, seven and 21days after restorations. Contralateral tooth intact enamel surface was determined as control side. Periotron8000 device was used for detection of GCF volume. Cytokine level of GCF was evaluated by Human ELISA kits. Data were analyzed using Mann-Whitney U test and Wilcoxon signed ranks test. The correlations between clinical parameters and biochemical parameters were examined by Spearman's rank correlation analysis. RESULTS: After restorative treatments PI and GI scores were decreased compared with baseline evaluations. There was a significant difference in GCF levels between experimental and control sites in all groups. GCF IL-6 levels in all groups except Filtek Z250, GCF IL-8 levels in all groups except Fuji IX, GCF TNF-α level in only Fuji IX showed significant differences between experimental and control sites. CONCLUSIONS: The obtained data supported that all of the tested materials caused changes in GCF cytokine levels.

The effects of overhang amalgam restoration on levels of cytokines, gingival crevicular fluid volume and some periodontal parameters.

PURPOSE: To evaluate clinical periodontal findings and GCF levels of tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6) and interleukin 8 (IL-8) in patients with overhang amalgam restorations before and after overhang restoration removal. METHODS: 22 volunteer subjects (age range: 22-42 years old) with 22 overhang Class II amalgam restorations were selected. GCF samples were obtained from adjacent and contralateral teeth for IL-6, IL-8 and TNF-α measurements and analyzed using enzyme-linked immunosorbent assay (ELISA) kits. The amalgam overhangs were removed and the readings were repeated at the end of 1 week. Clinical periodontal assessments, including gingival index (GI) and plaque index (PI) were performed at baseline and after 1 week. Data were analyzed using the paired t-test and independent sample t-test at a significance level of 0.05. Correlations were investigated using Pearson correlation analysis. RESULTS: A significant reduction in GI and PI was observed after removal of the overhanging restoration on Day 7. (P< 0.05) However, there was no significant difference between IL-6 (P= 0.857), IL-8 (P= 0.579) and TNF-α (P= 0.958) levels before and after overhang restoration removal. There were no significant correlations between laboratory findings and clinical parameters. CLINICAL SIGNIFICANCE: Dental restorations may produce periodontal disease and may alter tooth form, surface integrity, relationship with the periodontium and adjacent teeth. The marginal edge located in the gingival sulcus is likely the cause of the inflammatory reaction. This study showed significant improvement in clinical periodontal parameters after removing the overhangs of restorations.

The effect of different drinks on tooth color after home bleaching.

OBJECTIVE: This study evaluated the influence of coffee, tea, cola, and red wine staining on the color of teeth after home bleaching. MATERIALS AND METHODS: A total of 45 samples were obtained from 45 sound maxillary central incisors. The home bleaching procedure was performed using 10% carbamide peroxide gel applied to the sample surface for a period of 6 h each day, for 14 days. After bleaching, baseline color measurements were taken, and the samples were immersed in four staining solutions (coffee, tea, cola, and red wine) or artificial saliva (n = 9). Following 15 min and 6 h of immersion on the first day and next day, respectively, the samples were washed with distilled water for 10 s. After 15 min, 6 h, 1 week, and 1 month immersions, the color values of each sample were remeasured and the color change values (∆E) were calculated. Color change analysis was performed using a spectrophotometer. The results were analyzed using analysis of variance and Tukey's honestly significant difference test (P <0.05). RESULTS: Of all the staining solutions, the lowest ∆E values were observed with coffee staining versus artificial saliva (control group), for all time intervals evaluated after whitening. Although no statistically differences were observed between the coffee and control group at all the time points evaluated, there were statistically significant differences between the red wine, cola, and tea solutions. CONCLUSION: Following tooth whitening, patients should avoid drinks that cause tooth staining, particularly red wine, tea and cola.

Effect of water storage on the translucency of silorane-based and dimethacrylate-based composite resins with fibres.

OBJECTIVES: The purposes of this study were (1) to determine the translucency of silorane and dimethacrylate-based composite resins and (2) to evaluate the effect of water storage and reinforcement with fibre on the translucency of composite resins. METHODS: Two light-cured composite resins (A2 shade), Filtek Silorane (silorane-based composite) and Valux Plus (dimethacrylate-based composite), were used in this study. The first group was used as the control with no reinforcements, the second was reinforced with polyethylene (Ribbond THM) and the third was reinforced with a glass fibre (Everstick Net) for each composite resin. Colour measurements were measured against white and black backgrounds with a Shadepilot (Degu Dent Gmbh, Hanau, Germany) spectrophotometer and recorded under a D65 light source, which reflects daylight. CIELAB parameters of each specimen were recorded at baseline and at 24 h, 168 h and 504 h. Translucency of materials was calculated using the translucency parameter (TP) formula. Data were analyzed using repeated measures ANOVA and LSD post hoc tests (α=0.05). RESULTS: The highest baseline TP value was in the Valux Plus/non-fibre reinforced group (14.06±1) and the lowest in the Filtek Silorane/Ribond THM group (8.98±1.11). Repeated measures ANOVA revealed significant effects from the factors storage time, composite resin, composite resin×storage time and fibre×time (p=0.047; p=0.001; p=0.013; p=0.022, respectively). CONCLUSION: Within the limitations of the study, we concluded that inclusion of polyethylene and glass fibres did not alter the translucency of the different-based composite resins. The longest storage time resulted in the greatest change in translucency values of Filtek Silorane composite resins. CLINICAL SIGNIFICANCE: Considering the translucencies of composites with different formulations in the selection of composite resins for aesthetic restorations is important in terms of obtaining optimal aesthetic outcomes.

Three-year clinical performance of two indirect compositeinlays compared to direct composite restorations

Objective: Despite the incremental build-up of resin composite restorations, their polymerization shrinkage during curing presents a serious problem. Indirect composite resin systems represent an alternative in overcoming some of the deficiencies of direct composite restorations. The hypothesis of the present study states that the clinical performance of restorations may be affected by different generation and application techniques. Study Design: Sixty restorations (20 DI system (Coltène/Whaledent AG, Altstätten, Switzerland) composite inlays,20 Tescera ATL system (BISCO Inc. Schaumburg, Illinois, USA) composite inlays, and 20 direct composites)were applied to premolar teeth in 49 patients. Restorations were clinically evaluated by two examiners. Data were analyzed using the Kruskal-Wallis, Mann-Whitney U, Wilcoxon Signed Ranks, and X2 tests. Results: The Tescera ATL system performed significantly better than both direct composite restorations (p<0.001)and DI system (p<0.05).Conclusion: Within the limitations of this 3-year clinical study, indirect resin restorations showed better scores than direct restorations. In addition, the Tescera ATL system was found to be more successful than the DI system and direct composite restorations (AU)

Three-year clinical performance of two indirect composite inlays compared to direct composite restorations.

OBJECTIVE: Despite the incremental build-up of resin composite restorations, their polymerization shrinkage during curing presents a serious problem. Indirect composite resin systems represent an alternative in overcoming some of the deficiencies of direct composite restorations. The hypothesis of the present study states that the clinical performance of restorations may be affected by different generation and application techniques. STUDY DESIGN: Sixty restorations (20 DI system (Coltène/Whaledent AG, Altstätten, Switzerland) composite inlays, 20 Tescera ATL system (BISCO Inc. Schaumburg, Illinois, USA) composite inlays, and 20 direct composites) were applied to premolar teeth in 49 patients. Restorations were clinically evaluated by two examiners. Data were analyzed using the Kruskal-Wallis, Mann-Whitney U, Wilcoxon Signed Ranks, and X2 tests. RESULTS: The Tescera ATL system performed significantly better than both direct composite restorations (p<0.001) and DI system (p<0.05). CONCLUSION: Within the limitations of this 3-year clinical study, indirect resin restorations showed better scores than direct restorations. In addition, the Tescera ATL system was found to be more successful than the DI system and direct composite restorations.

The effects of silorane composites on levels of cytokines and periodontal parameters.

AIMS: The purpose of this pilot study was to determine the effects of silorane composites on gingival crevicular fluid (GCF) levels of tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6) and IL-8, GCF volume and clinical periodontal parameters in patients with silorane composite restorations before and after restorative treatment. MATERIALS AND METHODS: A total of 20 systemically healthy non-smokers, 12 female and 8 male (age range: 24-46 years), presenting with 25 instances of primary dentine caries with subgingival margins were selected for this study. Approval was obtained from the university ethics committee and treatment plans were approved by the patients. GCF samples were obtained with periopaper strips from relevant teeth for IL-6, IL-8 and TNF-α measurements. Each sample was stored at - 80°C and analyzed using the enzyme-linked immunosorbent assay (ELISA) kits. Cavities were prepared according to the common principles for adhesive restorations and restored with a silorane adhesive system (Silorane System Adhesive (3M ESPE) and silorane composite (Filtek Silorane, 3M ESPE). Cytokine levels were reassessed 2 weeks after restorative treatment. Data were analyzed using the independent t-test at a significance level of α =0.05. Associations between parameters were analyzed using Pearson correlation analysis. RESULTS: A significant increase in gingival index (GI) and plaque index (PI) were observed after 15 days (P < 0.05). GCF volume, IL-6, IL-8 and TNF-α levels exhibited significant differences before and after restorative treatment (P < 0.05). There were strong positive correlations among parameters except for PI/GCF volume and GI/GCF volume. CONCLUSION: Within the limitations of this investigation, silorane composites may have some negative effects on cytokine levels, clinical parameters and GCF volume.

The effects of amalgam restorations on plasma mercury levels and total antioxidant activity.

OBJECTIVE: This study evaluated the effects of amalgam restorations on plasma mercury levels and total antioxidant activities (TAA). DESIGN: The study was comprised of 48 subjects ranging in age from 20 to 32 years. Of these, 33 had dental amalgam restorations and 15 had no dental amalgam restorations. In those patients with amalgams, the total number of amalgam restorations and surfaces were counted, and the total and occlusal areas (mm(2)) of restorations were measured using a Counting Measurement Machine. Blood samples were collected from all participants. Plasma mercury levels were measured using an Atomic Absorption Spectrometer and Hydride System, and plasma TAA levels were measured using an Antioxidant Assay Kit. Statistical analysis was performed using the SPSS 10.01 software program. Data was evaluated by t test and correlation analysis. RESULTS: Plasma mercury (P-Hg) levels were found to be significantly higher in subjects with amalgam restorations when compared to subjects without amalgams (p<0.01); the differences in P-TAA levels between subjects with and without amalgams were not found to be statistically significant (p>0.05). No significant correlations were found between P-Hg concentrations and P-TAA levels (p>0.05). Significant positive correlations were found between P-Hg concentrations and the number of amalgam restorations (p<0.01), number of amalgam surfaces (p<0.05), total amalgam surface area (p<0.05) and amalgam occlusal surface area (p<0.01). However, no significant correlations were found between these parameters and P-TAA (p>0.05). CONCLUSIONS: The results of our study showed that dental amalgams are a major source of plasma mercury; however, amalgam restorations were not found to have a significant effect on plasma-total antioxidant activities.

Neuropsychological effects of low mercury exposure in dental staff in Erzurum, Turkey.

OBJECTIVE: To carry out measurements of the Hg levels and personal exposure in Turkish dental clinics, and to evaluate possible adverse effects on the CNS in dental personnel. SETTING: Five dental clinics (1 private, 4 public) in Erzurum, Turkey. SUBJECTS AND METHODS: 43, Hg vapour-exposed dental staff were examined and 43 hospital employees with no known exposure to Hg acted as the control group. Hg concentrations in plasma and urine were analysed by atomic absorption spectrophotometry. Possible effects on the central nervous system (CNS) were estimated by neuropsychological tests (Weschler Memory Scale-Revised (WMS-R) and Verbal Test of Memory Processes (VTMP)) and two self-administered questionnaires (Symptom Checklist-90-Revised (SCL-90-R) and Beck Depression Inventory (BDI)). RESULTS: The dental staff group had higher whole blood (B-Hg) and urine (U-Hg) Hg levels than the control group. The mean B-Hg value was 2.18 nmol/l and U-Hg was 1.17 nmol/mmol creatinine. U-Hg had an inverse relationship with logical memory (in WMS-R test) and total retention score (in VTMP test), and a positive relationship with increased scores of Anxiety and Psychoticism (in SCL-90-R). CONCLUSION: These results may represent long-term consequences of low Hg exposure. In dentistry, to decrease toxic effects, proper Hg hygiene should be practiced by all dental health care workers.