Effect of Different Mouthwashes on the Surface Microhardness and Color Stability of Dental Nanohybrid Resin Composite.

BACKGROUND: Surface microhardness and color stability of dental restorative material should be sustained throughout its functional lifetime to maintain the esthetic quality of the restoration. However, the frequent application of mouthwash may affect their surface microhardness and color stability. The aim of this study was to evaluate the effects of different types of mouthwashes with different contents on surface microhardness and color stability of dental nanohybrid resin-based composite. METHODS: Disc specimens of nanohybrid resin composite (Luna Nano-Hybrid Composite) were prepared according to manufacturing instructions; specimens were incubated for 24 h in three types of mouthwash (Chlorohexidine, Listerine Green Tea, and Colgate Optic White Whitening Mouthwash). Artificial saliva was used as a control group. Surface microhardness was evaluated using Vickers microhardness device. Color stability after and before immersion in the different mouthwashes was evaluated using extra-oral spectrophotometer; the values of color change (ΔE00) were subsequently calculated. Data were analyzed using one-way ANOVA and post hoc test (p ≤ 0.05). RESULTS: There was no significant difference between microhardness of resin composite immersed in artificial saliva, CHX, and Green Tea mouthwashes (78.5, 78.4, and 73.5, respectively) (p ≥ 0.1), while the bleaching mouthwash led to the lowest microhardness of resin composite, with significant difference compared to the three previous immersion media (p = 0.002). Moreover, there were significant differences in the color changes (ΔE00) of resin composite exposed to the various immersion media (p = 0.0001). CONCLUSIONS: The bleaching mouthwash led to a significant reduction in nanohybrid resin composite's microhardness compared to the chlorohexidine and Green Tea containing mouthwashes. The resin composite's color change was accepted in bleaching mouthwash but unaccepted in chlorohexidine and Green Tea containing mouthwashes.

Comparative evaluation of caries prevalence among group of Egyptian adolescents using DMFS and ICDASII methods: a cross-sectional study.

BACKGROUND: Limited data is available regarding the prevalence of dental caries as a chronic disease among adolescents using different caries assessment indices. The aim of this study was to compare and describe the prevalence of dental caries among group of Egyptian students using two caries assessment indices; DMFS and ICDAS II. METHODS: This descriptive, cross-sectional epidemiological study included 2760 public secondary school students with age range from 15 to 18 years with permanent dentition and good general health. Presence of; retained teeth, congenital or developmental anomalies in the permanent dentition, orthodontic treatments, systematic conditions, smoking and general health problems were considered the exclusion criteria in this study. Participants were selected randomly from 8 public secondary schools in the Great Cairo, Egypt. The examination was achieved by 6 trained and previously calibrated examiners using sets of diagnostic mirrors, compressed air, a WHO probe and cotton rolls. DMFS index and ICDAS II system were used as caries detection methods. In DMFS index; the number of decayed (D), missing (M) and filled (F) surfaces was recorded, while in the ICDAS II index, the assessment of both cavitated and non-cavitated carious, missed and filled teeth with restorations /sealants was recorded. The examiners performed the oral examination using both scoring systems in an alternating manner. The collected data were explored for normality using Kolmogorov-Smirnov and Shapiro-Wilk tests. Chi square test was used to analyze the frequencies. RESULTS: There was a statistical significant difference between the DMFS and ICDAS II methods results regarding the recorded number of caries affected teeth and cavitated teeth surfaces. The prevalence of dental caries among the investigated secondary school students was (69.56%) and (78.29%) for DMFS and ICDAS II, respectively. CONCLUSIONS: The prevalence of dental caries among Egyptian adolescent is high. ICDAS scoring system revealed higher caries prevalence values than DMFS method. ICDAS method is the best choice for the preventive goals, while DMFS is sufficient for clinical purposes.

Evaluation of Surface Properties of Two Remineralizing Agents after Modification by Chitosan Nano Particles: An In vitro Study.

Background: Calcium phosphate-based systems have been introduced as promising bio-mimetic materials due to their close resemblance to the enamel. Chitosan and its derivatives have been an emerging biomaterial due to their additional antibacterial effect and promising re-mineralizing ability. Aim: The aim of this study is to evaluate the effect of chitosan nanoparticles on the remineralization of the demineralized enamel surface after being added to nano-hydroxyapatite and nano-calcium phosphate materials. Setting and Design: This was in vitro study. Materials and Methods: Twenty specimens of extracted permanent molars were collected, and then immersed in demineralizing solution, then distributed into four groups according to the remineralizing material. Group 1: Treated with Nano-beta-tricalcium phosphate (Nß-TCP) gel, Group 2: Treated with Nß-TCP with chitosan gel, Group 3: Treated with Nanohydroxyapatite (NHA) gel, and Group 4: Treated with NHA with chitosan gel. The surface hardness of the teeth was measured at baseline, after demineralization, and after remineralization. The structural changes in each group were analyzed using the scanning electron microscopy. Statistical Analysis: Shapiro-Wilk's test, one-way ANOVA followed by Tukey's post hoc test was used. Results: In all groups, there was a significant difference in mean Vickers hardness number (VHN) at different intervals, with the highest value found after treatment (301.64-395.65) VHN, followed by the baseline (236.97-276.15) VHN, while the lowest value was detected after demineralization (121.23-124.39) VHN. It was also indicated that baseline treatment, the Hardness percentage change (%) of the nano NHA + Chitosan group showed the highest significant value (55.10%), while the Nß-TCP group exhibited the lowest significant value (9.56%). Conclusions: It can be concluded that NHA and NΒ-TCP modified by chitosan NPs as remineralizing agents of enamel surface hold promising results.

The Antibacterial Effect of Two Cavity Disinfectants against One of Cariogenic Pathogen: An In vitro Comparative Study.

INTRODUCTION: Bacteria residing in the oral cavity penetrate freely through the resultant fissures under the fillings, which might lead to the development of secondary caries. Nowadays dentistry, different nanotechnological materials with antibacterial activity are being developed for oral cavity disinfection. AIM: This study aims to investigate the antibacterial activity of a new cavity disinfectant NanoCare Plus Silver Gold® (NanoCare) in comparison to (0.2%) chlorhexidine (CHX) gluconate disinfectant against Streptococcus mutans growth and colony count using Agar well diffusion method and contact test, respectively, and also, to assess the nanoparticles (NPs) size distribution and Zeta potential of a NanoCare disinfectant. MATERIALS AND METHODS: A total of 36 samples of cavity disinfectants were divided into two main groups (G) (n = 18); G1: NanoCare, and G2: CHX. Each group was subdivided into two subgroups (C) (n = 9) according to the antimicrobial test that the samples were subjected to. RESULTS: A chlorohexidine group demonstrated the higher mean inhibition zone values than NanoCare group where P ≤ 0.05, as well both groups had a significant decrease in bacterial colony count where P ≤ 0.001. The particles size distribution in NanoCare sample was found that 99% of particles number with an average size of 29.07 nm and 1% was 136.7 nm, while the Zeta potential value was -6.5 mV. CONCLUSIONS: NanoCare cavity disinfectant displayed good antibacterial property against S. mutans. The innovative incorporation of NPs into this cavity disinfectant could be used to improve the antimicrobial capacity of the material and help to decrease secondary caries risk.