In-vitro evaluation of fracture resistance of teeth restored with different high-viscosity glass ionomer restorative materials and bulk-fill composite resins.

OBJECTIVES: This study aimed to evaluate the effect of restorations made with a glass-hybrid restorative system (GHRS), a high-viscosity glass ionomer restorative material (HVGIC), a high-viscosity bulk-fill composite resin (HVB), a flowable bulk-fill composite resin (FB), and a nanohybrid composite resin (NH), which are commonly preferred in clinical applications on the fracture resistance of teeth in-vitro. MATERIALS AND METHODS: One hundred intact human premolar teeth were included in the study. The teeth were randomly divided into ten groups (n = 10). No treatment was applied to the teeth in Control group. Class II cavities were prepared on the mesial surfaces of the remaining ninety teeth in other groups. For restoration of the teeth, a GHRS, a HVGIC, a HVB, a FB, and a NH were used. Additionally, in four groups, teeth were restored using NH, GHRS, and HVGIC with open and closed-sandwich techniques. After 24 h, fracture resistance testing was performed. One-way ANOVA and Tukey HDS tests were used for statistical analysis of the data. RESULTS: The fracture resistance values of Control group were statistically significantly higher than those of GHRS, HVGIC, FB, NH, HVGIC-CS, GHRS-OS, and HVGIC-OS groups(p < 0.05). There was no statistically significant difference observed between the fracture resistance values of Control, HVB, and GHRS-CS groups (p > 0.05). CONCLUSION: It can be concluded that the use of HVB and the application of GHRS with a closed-sandwich technique may have a positive effect on the fracture resistance of teeth in the restoration of wide Class II cavities. CLINICAL RELEVANCE: The use of high-viscosity bulk-fill composite resin and the application of glass-hybrid restorative system with the closed-sandwich technique in the restoration of teeth with wide Class II cavities could increase the fracture resistance of the teeth.

The effect of detox solution on color stability, roughness, and microhardness of monochromatic universal composite resins.

BACKGROUND: Currently, the advantages of monochromatic universal composite resin restorative materials have increased their use in dentistry. Accordingly, the optical, surface and mechanical properties of these materials have become more important. This study aimed to evaluate the effect of detox solution on discoloration, surface roughness (SR), and microhardness of different monochromatic universal composite resins (Omnichroma [O], Zenchroma [Z], Vittra [V], and Charisma Diamond One [CDO]). Another aim of this study was to evaluate the monomer conversion degree (DC) of the materials. METHODS: A total of 80 specimens were prepared to evaluate the materials (n = 10). After the initial measurements, the specimens were immersed in a red detox solution for 21 days. Statistical data analysis was performed using one-way ANOVA and Tukey's multiple comparisons. RESULTS: The ∆E values of Z were highest on the 21st day. There was an increase in the SR values of the materials immersed in the detox solution. On the 21st day, top surface microhardness of O was lower than the other materials. There was no statistically significant difference at DC values among material groups. CONCLUSIONS: The use of detox solutions for a commercially recommended period of 21 days is suggested. However, this usage period can cause discoloration in restorative materials. Furthermore, especially in the initial one-week period, detox solution may have a negative impact on the microhardness of the materials. In light of all these data, we recommend the cautious use of detox solutions to prevent adverse effects on restorative materials.

In Vitro Evaluation of Mechanical, Surface, and Optical Properties of Restorative Materials Applied with Different Techniques.

(1) Background: currently, the advantages of bulk-fill resin composite and high-viscosity glass ionomer materials have increased their use in dentistry; accordingly, their mechanical, surface, and optical properties have become more important. This study aimed to evaluate the mechanical, surface, and optical properties of three different restorative materials (a high-viscosity bulk-fill resin composite (TNC), a flowable bulk-fill resin composite (EBF), and a high-viscosity glass ionomer (FIX)) after application using different techniques (control, heat application, and ultrasonic activation). (2) Methods: specimens were prepared to assess the color stability and surface roughness (n = 12). The specimens were immersed in two different solutions for 14 days. For the compressive strength test, specimens were prepared using a Teflon mold (n = 12). (3) Results: among the specimens applied according to the manufacturer's instructions and immersed in distilled water, it was observed that the surface roughness values of FIX on the 7th day were statistically significantly higher than the other materials (p < 0.05). The compressive strength values of EBF applied using ultrasonic activation were significantly lower than those of EBF applied using the other techniques (p < 0.05). (4) Conclusions: coffee can negatively affect the color stability of restorative materials, but discoloration may vary depending on differences in the content of the material. All materials evaluated in this study exhibited clinically acceptable surface roughness values. It can be concluded that flowable bulk-fill resin composite is the most durable material in terms of compressive strength, so it can be used in the restoration of posterior teeth, especially those exposed to intensive stress.