Journal of Dental Medicine

Background and Aims: Using fissure sealant is one of the most effective methods of preventing pit and fissure decay. Fluoride has been added to various materials as a known anti-caries agent. Fluorinated graphene (FG) has gained attention due to its unique properties. The specific structural characteristics of graphene fillers, besides having antibacterial properties by increasing the rate of fluoride release and charge and neutralizing the acidic pH of the environment, is a suitable option in many treatments. This study investigated the effect of addition of fluorinated graphene nanoparticles on the fluoride release in Fissurit®, a commercial fissure sealant.
Materials and Methods: In this in vitro study, fluorinated graphene oxide (FGO) with bright white color was prepared. After synthesis, 0, 1, 2 and 4 by weight percent were added to the fissure sealant (Fissurit®). Then, the release of fluoride in this material was measured and compared with the commercial fissure sealant containing fluoride (Fissurit®).
Results: According to the obtained results, the amount of fluoride released from groups with different percentages of FGO had a direct relationship with the percentage of FGO addition. Also, at different times, there was a significant difference between the groups with FGO and the control group without FGO (P<0.001).
Conclusion: Addition of FGO to the fluorinated fissure sealant caused the release of fluoride and the possibility of recharging it. The power of releasing fluoride and its recharging in fissure sealant with FGO was higher than the fluorinated fissure sealant, but its fluoride was discharged at a faster rate.

Background and Aims: Repairing existing composite restorations, rather than replacing them entirely, is regarded as a conservative and tissue-preserving approach in restorative dentistry. However, achieving a durable bond between the aged and newly applied composite resin remains a significant clinical challenge. This study aimed to compare the shear bond strength of repaired composite restorations using three different adhesive systems.
Materials and Methods: In this in vitro study, which conducted at the Faculty of Dentistry, Urmia University of Medical Sciences, 60 disk-shaped composite specimens were fabricated with standard dimensions. After undergoing artificial aging (storage in distilled water for 6 months), their surfaces were roughened mechanically using a diamond bur. The specimens were randomly divided into three groups (n=20) and repaired using fifth-generation (Adper Single Bond), seventh-generation (OptiBond All-In-One), and universal (Single Bond Universal) adhesives, followed by the application of new composite. All  specimens were subjected to thermocycling, and the shear bond strength was measured using a universal testing machine. Fracture patterns of the samples were also examined using a stereomicroscope to determine the modes of failure. Data were analyzed using one-way ANOVA and Chi-square tests in SPSS at a significance level of 0.05.
Results: The mean shear bond strengths were 15.22 ± 4.47 MPa for Adper Single Bond, 14.05 ± 4.66 MPa for OptiBond All-In-One, and 13.44 ± 4.68 MPa for Single Bond Universal. No statistically significant differences were found among the groups (P=0.468). Fracture pattern distribution was also not significantly different (P=0.453), with predominantly cohesive or mixed failures observed across all groups. No adhesive failures were observed.
Conclusion: Under standardized surface preparation, none of the tested adhesive systems demonstrated a statistically significant advantage in the shear bond strength between the aged and new composite. Therefore, the choice of adhesive in composite repair procedures can be guided by practical considerations such as product availability, ease of application, and dentist preference.