Evaluation of the effect of various types of fluoride varnishes on color stability of a composite resin

BACKGROUND AND AIM: Fluoride varnish as an extrinsic factor may cause discoloration in tooth-colored restorative materials. This research compared the impact of different fluoride varnishes on color change of a composite restorative material. METHODS: This laboratory experimental study was conducted on 40 specimens of flowable composite resin were divided into four groups based on the brand of applied varnishes (Durashield, Nupro, Fluorilaque, and Profluoride varnishes) (n = 10). Color measuring (ΔE) was performed using the easy shade device and according to Commission Internationale de l’Eclairage (CIE) L*a*b* system at three times: 24 hours after immersing in artificial salvia (baseline), 24 hours after fluoride varnishes application and after brushing. The amount of color changes was calculated for all of the specimens as follows: ΔE1 (difference between fluoride application-base line), ΔE2 (difference between brushingfluoride application), and ΔE3 (difference between brushing-base line). P < 0.05 was considered as significant. Statistical analysis was performed by one-way ANOVA and post-hoc Tukey. RESULTS: The maximum and minimum color changes after applying varnishes were observed by Nupro and Profluoride, respectively. A significant difference was observed between ΔE 1 values of all types of studied varnishes (P < 0.01) except Durashield and Fluorilaque (P = 0.35). After brushing, no significant difference was shown between color change of stained specimens due to Durashield, Fluorilaque, and Nupro. There was no significant difference between ΔE 3 values of Durashield and Fluorilaque. CONCLUSION: Trends of color change after using all studied varnishes were clinically acceptable (ΔE < 3.3). Durashield, Nupro, Fluorilaque, and Profluoride varnishes can be used without adversely affecting the color of flowable composite resin. KEYWORDS: Fluoride Varnish; Discoloration; Resin Composit

Coronal Discoloration Induced by Calcium-Enriched Mixture, Mineral Trioxide Aggregate and Calcium Hydroxide: A Spectrophotometric Analysis

Introduction: The aim of this study was to compare the discoloration potential of calcium-enriched mixture (CEM) cement, white mineral trioxide aggregate (WMTA) and calcium hydroxide (CH), after placement in pulp chamber. Methods and Materials: Access cavities were prepared in 40 intact maxillary central incisors. Then, a 2×2 mm box was prepared on the middle third of the inner surface on the buccal wall of the access cavity. The specimens were randomly assigned into four groups; the boxes in the control group were left empty, in groups 1 to 3, the boxes were filled with CH, WMTA and CEM cement, respectively. The access cavities and the apical openings were sealed using resin modified glass ionomer (RMGI). The color measurement was performed with a spectrophotometer at the following intervals: before (T0), immediately after placement of the filling material (T1), one week (T2), 1 month (T3), 3 months (T4) and 5 months (T5) after filling of the box and finally immediately after removing the material from the boxes (T6). Color change (ΔE) values were calculated using the sample Kolmogorov-Smirnov test to determine the normal distribution of data, followed by ANOVA, repeated measured ANOVA and post-hoc Tukey’s tests. Results: All materials led to clinically perceptible crown discoloration after 1 week. The highest ΔE value belonged to WMTA group. Discoloration induced by CEM cement was not significantly different from CH or the control group (P&gt;0.05). Conclusion: CEM cement may be the material of choice in the esthetic region, specifically pertaining to its lower color changing potential compared to WMTA.Keywords: Calcium-Enriched Mixture Cement; Mineral Trioxide Aggregate; Spectrophotometry; Tooth Discoloratio

Evaluation of microleakage of Ionoseal filling material as a fissure sealant agent

Introduction: Sealing pits and fissures was introduced as an approach to prevent occlusal caries for more than two decades. The aim of this study was to compare the microleakage of flow able resin reinforced glass ionomer (Ionoseal) with other materials used as fissure sealants. Methods: In this in vitro study, 50 premolar teeth of human free of any caries were selected. Fissurotomy was done with fissure bur. The samples were randomly categorized into five groups (Fissurit FX, Fuji II light-cured,Grandio flow, Ionoseal). Ionoseal was assessed by using two methods: with and without etching and bonding agent prior to sealant application. After sealant placement, all surfaces of the teeth except 2 mm area around the sealant margins were covered with two layers of nail polish. The specimens were thermocycled, and they were sectioned after immersing into a 0.5 % basic fuchsine solution. The amount of microleakage was examined by stereomicroscope. Results: The microleakage comparisons of groups indicated that Ionoseal without etching and bonding application had significantly greater microleakage than the other groups (p0.05). Conclusions: By considering isolation difficulties in children and observing high amount of Ionoseal microleakage (without etching and bonding application), the samples need to be etched and bonded like other resin-based materials before Ionoseal placement in order to achieve clinically desirable microleakage outcomes

Effect of energy drinks on microhardness of silorane and dimethacrylate-based composite resins

Introduction: Increased consumption of energy drinks has raised concerns about their effects on dental restorations. This study assessed the effects of two energy drinks on the surface microhardness of methacrylate and silorane-based composites after 1-week and 1-month periods. Materials & Methods: In this in-vitro study, 90 cubic samples were prepared from Filtek P90, Filtek Z250 and Filtek Z350 XT composite resins. Vickers hardness test was performed to measure the baseline surface microhardness for each specimen. Ten randomly selected samples from each composite material were then immersed in one of the two sports drinks (Red Bull and Hype) or artificial saliva (control). Surface microhardness was re-evaluated after 1 week and 1 month of immersion. The data were evaluated using ANOVA via post-hoc Tukey tests and repeated measure test (α=0.05). Results: Surface microhardness of all composites were significantly decreased in energy drinks in both evaluation periods (P<0.001). In artificial saliva, microhardness was significantly increased after 1 week and decreased after 1 month of immersion (P< 0.001). After 1 month, the lowest microhardness changes were observed in Filtek Z350 XT composite. (18% and 14% reduction in Hype and Redbull respectively). Differences between energy drinks were significant for Z350 XT composite only after 1 week (P=0.01) and for Z250 composite after 1 week and 1 month (P=0.020 and P< 0.001 respectively). Conclusion: Hype and Red Bull energy drinks can affect the surface hardness of composite resins depending on their characteristics and exposure time

Gingival microleakage in class II composite restorations using different flowable composites as liner: an in vitro evaluation

Introduction: One of the main disadvantages of composites is marginal microleakage; using flowable composites as a liner beneath composite restorations has been recommended to reduce microleakage. The aim of this study was to assess the microleakage of class II restorations with different flowable composites liners. Materials &Methods: 45 extracted premolars teeth with class II cavity preparation (90 cavities) were divided into five groups and filled as follows: 1.control group: hybrid composite (Z250) 2. Z250+surefil SDR flow 3.Z250+filtek supreme xt flow composite 4.Z250+Grandio flow 5.Z250+Tetric flow. Mesial and distal cavities were filled using snowplow and layering technique, respectively. After that, the samples were immersed in 0.5% fuchsin solution and sectioned. Gingival microleakage was then graded. Data were analyzed using Kruskal Wallis and Mann Whitney U test. Results: There was no significant difference between the snowplow and layering methods. Microleakage of Tetric flow and Grandio flow liners was significantly higher than the control group. Other flowable composites showed no significant difference in comparison with the control group. Conclusion: In the present study, the results indicated that the flowable composites were not effective on reducing gingival microleakage

Comparative evaluation of the effect of Light Emitting Diode (LED) and Quartz Tungsten Halogen (QTH) light curing units on color stability of Filtek Z350 XT

Introduction: Discoloration of the resin-based composites is a common problem in restorative dentistry. There are many factors associatedwith the discoloration of dental materials in the oral environment. The purpose of this study was to evaluate the color changes in a nano-composite cured with a quartz-tungsten-halogen (QTH) and light emitting diode (LED) unit. Methods: 80 disk-shaped specimens were prepared using Filtek Z350 XT. The specimenswere cured with two LED units (Valo and BluephaseC5) andQTH )Astralis7(with two different energy density (400 & 750 mW/Cm²). The color of the materials was measured before and after immersingin tea and artificial saliva.Color change value (ΔE) were calculated and analyzed by 2-way ANOVA and Tukey’s test. Results:In artificial saliva group,the compositescured with Astralis7 and BluephaseC5 showed significantly more color stability. In tea group, the composites cured with BluephaseC5 significantly had the least color change. Conclusions:The type of light curing unitdoes not affectthe color stability. Exposure time and interaction between light source and photoinitiator content in composite may be the most important factors affecting color stability

Specific immune responses induced by multi-epitope DNA derived from Mycobacterium tuberculosis DosR antigens

One third of the world population are latently infected with Mycobacterium tuberculosis and are at the risk of reactivation of tuberculosis (TB). The most effective strategy for control of TB worldwide is the development of a vaccine that inhibits progression of latent TB to active infection. In this study, two optimized constructs consisting of multi-epitopes DNA derived from three latency antigens Rv2029c, Rv2031c, and Rv2627c fused with or without light chain 3 (LC3) are synthetized. The immunogenicity effectiveness of two DNA constructs was evaluated in the mouse model. LC3-fused multi-epitope DNA construct induced strong specific Th1 immune responses with high increase in IFN-γ+ CD4+ and IL-2+ CD4+ T cell populations (both with p + IL-2+ CD4+ T cell population (p + CD8+ T cell population (p + and CD8+ T cell populations. The results indicated that LC3-fused multi-epitope DNA construct has a potential to be investigated for future development of a new TB vaccine

Post-ictal Modulation of Baroreflex Sensitivity in Patients With Intractable Epilepsy

Objective: Seizure-related autonomic dysregulation occurs in epilepsy patients and may contribute to Sudden Unexpected Death in Epilepsy (SUDEP). We tested how different types of seizures affect baroreflex sensitivity (BRS) and heart rate variability (HRV). We hypothesized that BRS and HRV would be reduced after bilateral convulsive seizures (BCS).Methods: We recorded blood pressure (BP), electrocardiogram (ECG) and oxygen saturation continuously in patients (n = 18) with intractable epilepsy undergoing video-EEG monitoring. A total of 23 seizures, either focal seizures (FS, n = 14) or BCS (n = 9), were analyzed from these patients. We used 5 different HRV measurements in both the time and frequency domains to study HRV in pre- and post-ictal states. We used the average frequency domain gain, computed as the average of the magnitude ratio between the systolic BP (BPsys) and the RR-interval time series, in the low-frequency (LF) band as frequency domain index of BRS in addition to the instantaneous slope between systolic BP and RR-interval satisfying spontaneous BRS criteria as a time domain index of BRS.Results: Overall, the post-ictal modulation of HRV varied across the subjects but not specifically by the type of seizures. Comparing pre- to post-ictal epochs, the LF power of BRS decreased in 8 of 9 seizures for patients with BCS; whereas following 12 of 14 FS, BRS increased. Similarly, spontaneous BRS decreased following 7 of 9 BCS. The presence or absence of oxygen desaturation was not consistent with the changes in BRS following seizures, and the HRV does not appear to be correlated with the BRS changes. These data suggest that a transient decrease in BRS and temporary loss of cardiovascular homeostatic control can follow BCS but is unlikely following FS.Significance: These findings indicate significant post-ictal autonomic dysregulation in patients with epilepsy following BCS. Further, reduced BRS following BCS, if confirmed in future studies on SUDEP cases, may indicate one quantifiable risk marker of SUDEP

Comparative evaluation of microleakage of composite restorations using fifth and seventh generations of adhesive systems

Introduction: Simultaneous etching of enamel and dentin using the novel generation of adhesive systems with contracted operational steps, has shown a good clinical efficacy. The aim of this study was to evaluate the microleakage of composite restorations using the V and VII generations of adhesive systems on primary teeth. Methods: This study was performed on 45 human intact extracted primary teeth. Following class V cavity preparation, the samples were randomly divided into three groups included 15 teeth based on the type of bonding agent; Single Bond 2, Clearfil S3 Bond or G Bond. After applying the bonding agents, the teeth filled with composite Z250. The microleakage values of incisal and gingival margins were separately scored by 2% basic fuchsine staining based on a 0-3 ordinal ranking system. The data were analyzed by using Kruskal Wallis and Mann_whitney U tests. Results: In overall, the score of microleakage at incisal (0.58±0.94) and gingival (1.06±0.19) edges did not have significant difference. Also, there was no significant difference between incisal and gingival microleakage considering the different types of bonding. Conclusion: Regarding to less operational steps and lower risk of salivary contamination, the VII generation of dentin bonding agents can be applied for filling the class V cavities of primary teeth

Comparison of nuclear P16 immunostaining in atypical and normal endocervical glands: A descriptive analytical study

Background: Cervical cancer is one of the most common malignancies worldwide and a major problem in the healthcare system. Nowadays, the importance of biomarkers in the diagnosis of malignancies is proven. Some studies have pointed to the role of P16 in the diagnosis of cervical cancer. The purpose of this study was to compare the nucleic reactivity with P16 antibody in atypical vs normal endocervical glands. Methods: We enrolled 60 patients who had undergone the hysterectomy due to non-endocervical causes at Alzahra University Hospital of Tabriz University of Medical Sciences to a descriptive-analytical study. We selected 25 patients with atypical endocervical glands and 35 subjects with normal glands based on the pathologic examination using hematoxylin-eosin staining. Then, we assessed the frequency of nucleic reactivity of the tissues with P16 antibody in both groups. Results: No P16 expression was observed in any of the samples from normal subjects. However, only 2 (8.0%) out of 25 samples from the atypical group, were not reactive to the P16 antibody. Also, 20 samples (80.0%) were diffusely stained continuous, whereas three samples (12.0%) were stained locally. Accordingly, in the group with atypical endocervical glands, the reaction with P16 antibody was significantly higher than that of normal endocervical glands (p= 0.001). Conclusion: P16 biomarker may play a role in the pathogenesis and progression of cervical cancer and can be used as a diagnostic marker for this purpose