Purpose: To assess the effect of incorporation of 5 wt% nano-hydroxyapatite particles (Nano-HAp) on the ultra-morphological characteristics of sound and cariesaffected dentin substrate/ conventional glass ionomer cement (CGIC) and resinmodified glass ionomer cement (RMGIC) interfaces. Materials and Methods: Occlusal surfaces of 16 extracted permanent human caries-free molars were ground to expose flat dentin surfaces. Half of the specimens (n=8) were subjected to pHcycling to create artificial caries-affected dentin. Specimens were randomly restored with one of the tested restorative materials either control (CGIC and RMGIC) or experimental (CGIC and RMGIC modified with Nano-HAp). Different restorative materials were mixed according to manufacturer instructions and then built-up on the sound or caries-affected dentin surfaces. All specimens were stored in artificial saliva either for 24 hours or 9 months. Specimens were then prepared and observed under field emission scanning electron microscope (FESEM) for ultra-morphological evaluation of dentin-restoration interfaces. Results: FESEM observations showed no marked ultramorphological changes in Nano-HAp modified groups/ dentin interfaces in compared to control groups. There was significant increase in microcracks and pores within the matrix of all GIC groups. Moreover, there were multiples microcracks extended all over the restorations matrix with microgaps formation at dentin-restoration interfaces for all caries-affected dentin and 9 months aging period groups. Conclusion: The unique properties of glass ionomer cements were greatly diminished with bonding to caries-affected dentin and gradually declined with aging process. While there was no additional effect was observed from addition of Nano-HAp to these tested cements regarding their ultra-morphological characteristics features under FESEM.

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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Background The aim of this study was to compare the clinical performance of Nano-hydroxyapatite-modified conventional glass ionomer cement (NHA-GIC) and Nano-hydroxyapatite-modified resin-modified glass ionomer cement (NHA-RMGIC) with conventional glass ionomer (CGIC) and resin-modified glass ionomer (RMGIC) in the treatment of caries class V cavities. Sixty patients with at least two cervical caries lesions participated in this study. A total of 120 class V cavities were prepared and then restored using different restorative materials. Restorations were clinically evaluated according to modified United States Public Health Service criteria at baseline and after 3, 6 and 9 months. Results There was no statistically significant difference in the clinical performance of the different restorative materials at any of the follow-up periods. However, throughout the study period there was a statistically significant change in the color match, surface texture and marginal integrity in NHA-GIC. A statistically significant change in the surface texture and marginal integrity was found in GIC. On the other hand, there was only a statistically significant change in surface texture in NHA-RMGIC. Conclusions All tested restorative materials, control (CGIC and RMGIC) as well as experimental (NHA-GIC and NHA-RMGIC), exhibited comparable clinical performance after 9 months follow-up.

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