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Purpose: To evaluate the effect of Actilux-activated whitening toothpaste and Marine salts powder on color change and microhardness of bovine enamel. Methods: Thirty intact bovine incisors were used in this study to produce enamel specimens. The specimens were randomly distributed into three groups (n= 10) according to the tested whitening agents as follows: Group I: BW; BlanX LED White Shock (Actilux-activated), Group II: MS; Marine salts whitening powder and Group III: CR; Crest regular fluoridated toothpaste. The specimens were stained using black tea solution for 5 days. Each specimen was brushed twice daily for 8 then 15 days. The color was assessed according to CIE (Lab) color system using a VITA Easyshade spectrophotometer. The microhardness was assessed using Digital Display Vickers Microhardness Tester at baseline, after staining, after 8 days, and 15 days brushing. Data were tabulated and statistically analyzed. Results: After 8 days brushing, BW showed the highest mean (ΔE) while MS and CR both showed lower mean (ΔE). BW and MS showed the highest mean (ΔE) after 15 days brushing with no statistically significant difference between them. After 15 days; BW showed the highest mean microhardness followed by MS while CR showed the lowest mean microhardness. Conclusion: Both Actilux-activated toothpaste combined with LED device and Marine salts powder were effective in tooth whitening as well as increasing enamel microhardness. The whitening efficacy and microhardness is time dependent.

Objective: To investigate microshear bond strength of bioactive restorative material to enamel and dentin bonded using universal adhesive in etch and rinse and self-etch mode stored for 24h and 6 m. Methods: Sound bovine incisors were used in this study. ACITVA Bioactive restorative (Pulpdent Corp., Watertown, MA, USA) and Single Bond Universal adhesive (3M ESPE, St.Paul, MN, USA) were used. Teeth were grouped into 6 grouped according to bonding protocol (No bonding agent, bonding in etch and rinse mode and bonding in self-etch mode) and tooth substrate (enamel and Dentin). Specimens were stored for either 24 h or 6 m. Microshear bond strength (µSBS) were tested using universal testing machine and micromorphological observation of the interface were investigated using ESEM. Data were tabulated and statistically analyzed using Two-way ANOVA followed by Bonferroni’s post-hoc test. Results: Enamel bonded in etch and rinse mode recorded the highest µSBS values at both storage periods. Dentin at 24 h showed no significant difference between etch and rinse and self-etch modes while after 6 m, etch and rinse protocol showed significant drop. Control group recorded the lowest µSBS at all experimental groups. Conclusion: Use of bonding agents is recommended with ACITVA to both enamel and dentin. Universal adhesives are preferred in etch & rinse mode with enamel and self-etch mode with dentin. ACITVA is able to preserve bond strength upon storage except for dentin bonded in etch and rinse mode.

Purpose: To evaluate the antibacterial effect of Bioactive composite versus Glass ionomer using different storage media. Materials and Methods: Three restorative materials were used in this study (Reliafil Lc, Amalgomer and Conventional Glass Ionomer). 90 Disk- shaped specimens (2.5 mm height and 8 mm diameter) were prepared from each material. Groups were divided into three subgroups according to storage media (Acids, artificial saliva and de-ionized water). Bacterial strains were polished at 370c for 24h in Brain Heart Infusion broth which attained from stock cultures. Disk diffusion agar method was used for antimicrobial liability. The inhibition zone diameter around the specimen were measured at three times by the same operator after 48hs using electronic digital caliper. Results: This study found that Amalgomer has the highest antibacterial effect in lactic acid. Whereas, Conventional GIC has the highest antibacterial effect in artificial saliva and Bioactive composite in deionized water. Conclusion: This study was concluded that all the restorative material tested had an antibacterial effect in all storage media though Amalgomer seemed to be more prominent in lactic acid.

Objective: To evaluate the antibacterial effect of Aloe Vera and glass ionomer modified by Aloe Vera on Streptococcus mutans in comparison to Chlorhexidine.Methods: A total of fifty samples were used in the study and divided into 5 groups according to the materials used (n=10) Group 1:2% Chlorhexidine gluconate(CHX); Group 2: Aloe Vera (AV); Group 3: Glass ionomer (GI); Group 4: 2% Chlorhexidine gluconate added to glass ionomer (CHX+ GI) and Group 5: Aloe Vera added to glass ionomer (AV+GI) and. The antibacterial effect of each group were assessed by disc diffusion methods after two-time intervals: 24 and 48 hours. Data were tabulated and statistically analyzed using Two-way ANOVA followed by Bonferroni’s post-hoc test.Results: There was a statistically significant difference between the materials used on inhibition zone diameter after 24 and 48 hours. CHX showed the statistically significantly highest mean inhibition zone diameter followed by AV > CHX + GI > AV + GI. GI group showed the lowest mean inhibition zone diameter with a statistically significantly. Conclusion: Aloe Vera is beneficial in the inhibition of Streptococcus mutans growth up to 48 hours. The incorporation of Aloe Vera in glass ionomers seems to improve the antibacterial activity of glass ionomer restoration.

Objective: This research was conducted to investigate the effect of chemical challenge on the compressive strength (CS) and surface roughness (Ra) of a ceramic reinforced glass ionomer in comparison to a nanofilled resin composite. Methods: A total of 60 disc specimens (6mm height x 4mm diameter) were prepared for the compressive strength testing and another 60 disc specimens (5mm diameter x 2mm thickness) for the surface roughness testing. Specimens were divided into 2 groups (n=30) according to the material used; ceramic reinforced glass ionomer (Amalgomer CR, Advanced Health Care Ltd, Tonbridge, Kent, UK) and nanofilled resin composite (FiltekTM Z350 XT, 3M ESPE, St.Paul, MN,USA). Each group was divided into 3 subgroups (n=10) according to the storage media; distilled water (control), 0.02N citric acid and 50% ethanol. Specimens were stored for 7 days at 37oC. After storage period, they were subjected to compressive loading using a universal testing machine and surface roughness testing using white light interferometer. Data were tabulated and statistically analyzed using Two-way ANOVA followed by Bonferroni’s post-hoc test.Results: Amalgomer CR recorded a significantly lower CS and higher Ra than nanofilled resin composite under different storage media. Citric acid revealed the lowest CS of Amalgomer CR followed by ethanol in comparison to distilled water with significant difference between them. For nanofilled resin composite, both citric acid and ethanol significantly decreased CS. Ethanol showed the highest Ra values for both restorative materials. Conclusions: The performance of Amalgomer CR under different storage media was inferior to nanofilled resin composite regarding compressive strength and surface roughness. Citric acid severely affected compressive strength of Amalgomer CR. Nanofilled resin composite was able to preserve its surface roughness within the clinically acceptable threshold after chemical challenge in contrary to Amalgomer CR.

Objectives: This study was designed to evaluate the effect of natural cross linkers (Propolis and Hesperidin) on shear bond strength (SBS) to dentin after storage in different media. Materials and Methods: Ninety extracted molars were used and divided into three main groups according to dentin surface treatment (n=30) where, A1: treated with Propolis, A2: treated with Hesperidin and A3: receive no treatment to serve as a control group. Each group was further subdivided into 3 subgroups (n=10) according to the storage media either stored in Acids (B1) or stored in Artificial saliva (B2) orstored in distilled Water (B3). The shear bond strength (SBS) was determined using a universal testing machine. Results: The dentin specimens treated with Propolis showed significantly highest SBS. Conclusion: Both Propolis and Hesperidin cross linking agents are considered beneficial in improving bonding to dentin, though Propolis was much more effective. Storage media has deteriorating effect on resin-dentin shear bond strength.

Objective: To investigate the effect of some natural antioxidants on microshear bond strength to enamel bleached using chemical and laser assisted bleaching. Methods: Sound human maxillary central incisors were used in the study. The labial surfaces were ground to obtain flat enamel surfaces. Bleached specimens were divided into 2 main groups according to the bleaching protocol; chemical bleaching and laser assisted bleaching. Each group was subdivided into 4 subgroups according to the antioxidant used; 10% Ascorbic acid, 10% Alpha-tocopherol, 10% Hesperidin and No antioxidant. Non-bleached specimens were prepared to be used as a control group. Bonding procedures were done 1h after bleaching. Microshear bond strength (µSBS) was tested using a universal testing machine. Data were tabulated and statistically analyzed using Two-way ANOVA followed by Bonferroni’s post-hoc test.Results: The control group showed the highest µSBS value. Using hesperidin and ascorbic acid with both bleaching protocols recorded no significant difference compared to the control group. Also, laser bleaching without antioxidant was statistically comparable to the control group. Regarding type of antioxidant, hesperidin showed the highest µSBS results followed by ascorbic acid while α-tocopherol showed the lowest values.Conclusion: Hesperidin and ascorbic acid have the ability to regain microshear bond strength to bleached enamel with superior performance of hesperidin. Alpha tocopherol is not able to reverse compromised bond strength after tooth bleaching. Laser assisted bleaching could allow immediate bonding procedures without the need for antioxidant application.