Aim: White spot lesions are the only carious process lesions that can be remineralized noninvasively. The focus of modern dentistry is stopping the caries process without unnecessary damaging the tooth structure. The present clinical trial aimed to assess the remineralizing effect of eggshell powder (ESP) compared to Casein Phosphopeptide-Amorphous Calcium Phosphate (CPP-ACP) in carious post-orthodontic white spot lesions orthodontic treatment.Methodology: Twenty-Four patients were selected from the Clinic of Orthodontic Dentistry Department, Faculty of Dentistry, Cairo University. Patients were divided into two groups according to the treatment received either ESP gel or CPP-ACP paste (GC Tooth-Mousse). The participants were instructed to use pea size eggshell powder gel or GC Tooth Mousse on the teeth surfaces using a clean finger twice daily after brushing their teeth with Colgate Total Original Care toothpaste. WSLs were assessed at baseline, 1 month, 3months and 6 months by DIAGNOdent (Kavo, Germany).Results: Data were analyzed using Two-way ANOVA showed that there was no statistically significant difference in overall DIAGNOdent mean readings between ESP and GC Tooth Mousse groups at (P=0.136). Conclusion:Based on the data obtained in this study, it is suggested that ESP is effective and has a promising future in the treatment of post-orthodontic WSLs.

Objective: the aim of the study was to investigate the effect of epigallocatechin-3-gallate (EGCG) from green tea extract as collagen cross linking agent on dentin bond durability at different aging times. Materials and Methods: thirty sound premolars were used, they were divided into two groups (15 each) according to the pretreatment protocol. Mid-coronal flate dentine surface was obtained. Group A had no pretreatment done, where bonding agent was placed as the manufacturer instructions. Group B had EGCG pre-adhesive conditioner rubbed before bonding procedures. Bonding procedure was followed by the application of nano-hybrid resin composite in tygon tubes for micro-shear bond strength measurement. Each group was further subdivided in to three subgroups according the aging protocol, where T1 specimens were stored for 24 hours, T2 they were stored for 6 months and T3 they were thermocycled. Results: All data was statistically analyzed, where group B showed statistically significant higher mean bond strength values (19.5 MPa) than group A (12.1MPa) regardless of the aging protocol. There was statistically significant change in micro-shear bond strength results due to aging regardless of the pretreatment. Where T1 revealed the highest mean values (17.1MPa) followed by T3 (15.5 MPa) and the lowest mean values were reported with group T2. There was a statistically significant decrease in mean micro-shear bond strength from T1 to T2 followed by non-statistically significant change in micro-shear bond strength from T2 to T3. The mean micro-shear bond strength at T3 showed statistically significantly lower value compared to T1 value. Conclusion: Green tea extracts (EGCG) is a powerful source of proanthocyanidin that has proved to be a good biological substitute as a cross-linker for preserving the integrity of dentin, enhancing the tooth resin composite interface when compared with universal adhesives present now a days in the market. Recommendation: More long term clinical and laboratory studies are needed to assess the durability of adhesives.