BACKGROUND: Coral calcium is a new biomimetic product and dietary supplement which consists mainly of alkaline calcium carbonate. AIM: The aim of the current study is to compare the remineralization effect of coral calcium in different formulations and application methods. METHODS: A total of 35 extracted molars was collected, examined, and sectioned to obtain 70 sound enamel discs, all specimens were examined for calcium mineral content using energy dispersive analysis of X-rays (EDAX) coupled with scanning electron microscope. Hydroxyapatite (HA) nanoparticles were synthesized through wet chemical precipitation approach and characterized by transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR) analysis. Teeth specimens were subjected to demineralization, and mineral content was measured, specimens were divided into ten groups according to the remineralizing agent used, where Groups 1–3 used 10, 20, and 30 weight % (wt.%) coral calcium gel, respectively, Groups 4–6 used 10, 20, and 30 wt.% coral calcium and nanohydroxyapatite mix gel, and Groups 7–9 used 10, 20, and 30 wt.% coral calcium with argon laser activation and Group 10 (control group) without a remineralizing agent. All groups were re-examined by EDAX after remineralization. RESULTS: The TEM and FT-IR analysis confirmed the formation of rod shape HA in nanoparticles size range. All groups showed a statistically significant decrease in calcium level after demineralization, all groups showed a statistically significant increase in calcium content after remineralization except for the control group. Moreover, Groups 2 and 8 showed the highest increase in calcium level after remineralization. CONCLUSION: Coral calcium showed a significant remineralizing effect on carious enamel (demineralization) with an optimum concentration of 20 wt.%.

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.

Background Three types of gypsum products were commonly used in dentistry to fabricate dental casts and dies which includes dental plaster, dental stone, and improved stone. Improved stone could be used as final casts and dies for building of final indirect dental restorations. Even though the cost of dental plaster is very low, their inherent lowest surface microhardness, compressive strength, and dimensional stability values confined their utilization as preliminary cast and die materials. This in vitro study was evaluated the effect of incorporation of 10 weight % (wt.%) aluminum oxide nanoparticle fillers on surface microhardness, compressive strength, and setting expansion of the dental plaster compared with the gold standard improved stone. Methods The control group was prepared by mixing dental plaster with water. The innovative reinforced dental plaster group was prepared by incorporation of 10 wt.% aluminum oxide nanoparticle fillers to the conventional one prior to water mixing. The improved stone group was prepared by mixing the improved stone with water. Chemical composition of the three group powders was determined using x-ray florescence spectrometer (XRF). The surface microhardness, compressive strength, and setting expansion were measured. Results The results revealed that innovative dental plaster reinforced by 10 wt.% aluminum oxide nanoparticle fillers was shown higher mean surface microhardness than that of conventional dental plaster, while higher mean compressive strength values than that of improved stones and conventional dental plaster. Moreover, reinforced dental plaster was shown lower mean setting expansion values compared with conventional dental plaster and improved stones (P value ≤ 0.05). Conclusion Within limitation of this study, the results are indicating the opportunity of the innovative reinforced dental plaster to be used alternatively to improved stone (type IV) for fabrication of final dental casts and dies.

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.

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