Homayoon Alaghehmand

Objectives: This study assessed the effect of using Endo‐Activator on pushout bond strength (PBS) of radicular dentin to prefabricated fiber post in using epigallocatechin gallate (EGCG) and aloe vera natural matrix metalloproteinase (MMP) inhibitors. Materials and Methods: This in vitro study was conducted on 120 extracted teeth in 2 groups with/without using Endo‐Activator for root canal irrigation, each with 3 subgroups of LuxaBond primer (I) alone, (II) with aloe vera, and (III) with EGCG. After root canal treatment and post space preparation, radicular dentin was etched, the respective primer was rubbed on radicular dentin, and fiber posts were cemented using LuxaBond dual‐cure adhesive and LuxaCore Z dual‐cure cement. Each tooth was horizontally sectioned at the coronal, middle, and apical thirds, and the PBS of fiber post to dentin was measured immediately and after 6 months. Failure mode was determined under a stereomicroscope (×80). Results: Irrigation with Endo‐Activator improved both the immediate and 6‐month PBS in all sections ( p < 0.05). The highest immediate PBS was recorded in the coronal third in the aloe vera subgroups with no significant difference between use/no use of Endo‐Activator ( p > 0.05). At 6 months, aloe vera yielded the highest PBS in the coronal third, with significantly higher values in use of Endo‐Activator ( p < 0.05). Conclusion: Irrigation with Endo‐Activator along with the application of EGCG and aloe vera significantly improved the PBS of fiber post to radicular dentin and its durability; this effect was greater in the cervical third in the aloe vera subgroups both immediately and after 6 months.

Objectives: This study aimed to assess the impact of incorporating glass ionomer fillers of varying sizes on fluoride release, antiplaque properties, and the abrasive effects of toothpaste.Materials and Methods: In this laboratory study, three toothpaste samples containing glass ionomer filler particles (0.5, 5 µm, and a hybrid combination of equal proportions of both fillers) were tested, along with a base toothpaste without fillers or fluoride and a commercial toothpaste (Colgate Total) as controls. Fluoride release was measured using a fluoride ion‐selective electrode. Antiplaque properties were assessed by evaluating the effect of toothpaste on cultured saliva in tissue culture plates, with optical density measured using an ELISA reader. Abrasive effects were analyzed by changes in enamel thickness of bovine teeth using a three‐body wear test. Data were analyzed with ANOVA and Tukey's tests in SPSS software at a 0.05 significance level.Results: Toothpaste containing 0.5 µm fillers showed the highest fluoride release, whereas the lowest release was associated with 5 µm fillers. All formulations demonstrated antiplaque activity, though differences among filler‐containing toothpastes were not statistically significant (p > 0.05). Enamel abrasion differed significantly among the samples (p < 0.001), with the greatest abrasion observed for toothpaste containing 5 µm fillers and the least abrasion observed for 0.5 µm fillers.Conclusions: Incorporating glass ionomer fillers into toothpaste formulations provides fluoride release and antiplaque effects comparable to those of commercial toothpaste. Smaller filler sizes enhance fluoride release and reduce abrasiveness, though filler size does not significantly influence antiplaque efficacy.

Objectives: This study assessed the effects of 15% and 20% carbamide peroxide (CP) on color, surface roughness, and hardness of computer‐aided design/computer‐aided manufacturing (CAD/CAM) dental ceramics.Materials and Methods: This in vitro study was conducted on 120 Vita Mark II, Celtra Duo, and Suprinity CAD/CAM ceramic specimens. The ceramic specimens in each group (n = 40) were randomly assigned to two subgroups (n = 20) for polishing and glazing, and their baseline color, surface roughness (Ra), and hardness were assessed. In each subgroup, half of the specimens were exposed to 15% CP, while the other half were exposed to 20% CP. Their color change (ΔE), surface roughness, and hardness were then measured again. Surface roughness, hardness, and color were analyzed sequentially by profilometer, Vickers hardness tester, and spectrophotometer, respectively. Data were analyzed by repeated measures ANOVA, one‐way ANOVA, and post hoc Bonferroni test (α = 0.05).Results: The surface roughness of all groups significantly increased after bleaching treatment (p < 0.05). Surface hardness of all groups decreased after bleaching treatment, but this reduction was only significant in Vita Mark II subgroups (glazed, polished, 15%, and 20% CP). The ΔE was not clinically and visually perceivable in any group.Conclusion: The present results revealed that concentration of CP and type of surface treatment affected the surface properties of CAD/CAM ceramics. Type of surface treatment only affected the surface hardness of Vita Mark II ceramics (p < 0.05). Concentration of CP had a significant effect only on polished Vita Mark II.

E, we aimed to evaluate the impacts of adding ZnO and GO nanoparticles on the antibacterial properties of flowable composites. Materials and Methods: In this, in vitro experimental study was designated into five groups containing: (1) no nanoparticles as control group, (2) 1 wt.% ZnO nanoparticle, (3) 1 wt.% GO, (4) 1 wt.% physical compound of ZnO and GO, and (5) 1 wt.% chemical compound of ZnO and GO. The antibacterial properties of composite resin discs were evaluated by direct contact test. Data were analyzed using a one-way analysis of variance, followed by Tukey' post hoc tests (P = 0.05). Results: Streptococcus mutans colony counting in the first 24 h showed the least growth rate in the chemical compound group (2.2 × 10[5]). However, in 7 days, the least colony number was observed in the GO group (2 × 10[3]). Moreover, the physical compound showed the least bacterial adhesion. Conclusion: Adding GO alone to composites, compared to adding ZnO or physical and chemical compounds of GO-ZnO, was more helpful to increase the antimicrobial characteristics....

Background: This study aimed to assess the effect of graphene oxide (GO) nanoparticles mouthwash on oral mucosa, Streptococcus mutans (S. mutans) count in the saliva of rats, and human enamel surface microhardness, in comparison with fluoride mouthwash. Methods: This study was conducted in two phases namely an animal study, and ...

Objectives: This study aimed to evaluate the effects of hydrofluoric acid (HF) concentration and etching time on the surface roughness (SR) and three-point flexural strength of Suprinity and to analyze the surface elements before and after etching. Materials and Methods: To measure the SR, 70 specimens of Suprinity (2×4×5mm3) were assigned to seven groups (n=10). Six groups were etched for 20, 60, and 120 seconds with 5% and 10% HF and 7th group was the control group. Specimens were evaluated using atomic force microscopy (AFM). One specimen from each group was used to analyze the surface elements using scanning electron microscopy (SEM). For measuring the three-point flexural strength, 60 specimens were divided into six groups (n=10) and etched as previously described. The flexural strength was measured using a universal testing machine. T-test, one-way analysis of variance (ANOVA), and two-way ANOVA were used for statistical analyses (P<0.05). Results: The 10% concentration of HF caused higher SR compared to the 5% HF. The effect of HF concentration on the flexural strength was significantly different in the 20- and 60-second etching groups. Different etching times had no significantly different effect on the SR. With 5% HF, the flexural strength was significantly higher for 20-second etching time than for the etching times of 60 and 120 seconds. With 10% HF, there was a significant difference in flexural strength between etching times of 20 and 120 seconds. The atomic percentage (at%) of silica was enhanced by increasing the etching time. Conclusions: The best surface etching protocol comprises 10% HF used for 20 seconds.

SUMMARY: Objective: Computer aided design-computer aided machining (CAD-CAM) ceramic crowns are replacing ceramo-metal ones due to newly developed mechanical properties and esthetics. To obtain knowledge about their interactions due to polishing and occlusal contacts with the opposing dental enamel specimen, including surface roughness and wear, the three-body wear simulation was investigated. Methods and Materials: The surface roughness (RA) and wear rate (mm) of four CAD-CAM blocks with different compositions including Vita Mark II, e.max, Suprinity, and Enamic, after two surface treatments of glazing and polishing, and their opposing enamel specimens, were investigated using a mastication simulator and atomic force microscope. Results: The roughness of all ceramic and to a greater extent enamel samples, with the exception of enamel opposing polished Enamic samples, was decreased after wear. No significant difference in wear was evident for the ceramic samples between the glazed and polished treatments. Lower wear rates were recorded only for polished Vita Mark II and polished Enamic in comparison to the glazed ones. Conclusion: The newly developed polishing systems for CAD-CAM ceramics can be good alternatives to reglazing, because the roughness and wear rate of both the ceramic and the opposing enamel will either not change or decrease.