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Two fractured maxillary central incisors were restored via the crown fragment reattachment technique with adhesive systems and composite resin material. A long-term successful outcome was achieved after 4 years of follow-up. The patient presented with fractured maxillary central incisors, and a comprehensive intraoral and radiographic examination revealed that both teeth had extended crown fractures with no pulpal exposure (Class II, Ellis and Davey). The tooth fragments were thoroughly cleaned and inspected before being repositioned. Both fragments were in excellent condition with almost no pieces missing. Therefore, the proposed treatment was fragment reattachment. After verifying the repositioning and adaptation of the fractured fragments, a flowable composite was used to perform the reattachment procedure under rubber dam isolation. With modern dental adhesives, the reattachment of tooth fragments in good condition is considered a more conservative option for restoring tooth morphology, esthetics, and function. Although one tooth showed signs of irreversible pulpitis and required root canal treatment 2 weeks after the restoration, the clinical and radiographic evaluations at the 4-year follow-up visits confirmed the success of the restorative treatment. The restorations showed good functional and esthetic outcomes after 4 years of follow-up. [ABSTRACT FROM AUTHOR]

Objective: The aim of this in vitro investigation is to study the effect of endodontic cavity design on interfacial voids, class II resin composite sealing ability, and fracture resistance in mandibular premolars. Methods: A total of 48 single-rooted mandibular premolars received compound class II preparations with either traditional flare access cavities (group A) or contracted endodontic cavity preparations (group B). Each study group was subdivided according to the coronal restoration into two sub-groups as α and β. In the α group, a microhybrid composite was used after etch-and-rinse bonding technique using an MDP-containing universal adhesive. In the β group, a self-adhesive composite was used as coronal restoration after endodontic treatment (n = 12) for each subgroup. A micro-CT analysis was performed to assess the obturation interfacial voids and tracing of class II cervical interfacial adaptation. The tooth fracture resistance testing was then performed adding an extra group of 12 sound non-prepared teeth, which were tested as the control for fracture strength testing. A one-way ANOVA and post-hoc testing were used together with descriptive statistics for an analysis of the mean values of obturation interfacial voids. A two-way ANOVA was used to assess the fracture resistance test results, and to find the influence of endodontic access design and the type of composite material on the fracture resistance testing. Chi-square testing was employed to analyze the cervical interfacial seal of the class II restorations. Results: A one-way ANOVA revealed that there were no statistically significant differences between test groups in the amount of obturation interfacial voids (p > 0.05). There were no statistically significant differences between test groups in terms of cervical interfacial sealing ability (p > 0.05). A two-way ANOVA revealed that no statistically significant differences between test groups including the control group existed in terms of the fracture resistance testing (p > 0.05). Conclusions: Although it does not improve tooth fracture resistance, the contracted endodontic access cavity does not deteriorate the quality of obturation in terms of the interfacial porosity. The self-adhesive composite does not improve the efficiency of cervical interfacial adaptation or tooth fracture resistance regardless of the endodontic access cavity shape, yet it revealed a substantial load-bearing capacity. [ABSTRACT FROM AUTHOR]

Purpose: This in vitro study investigated the effects of dietary solvents on the microhardness and color stability of CAD/CAM provisional restorations compared to conventional materials. Methods: Disc-shaped specimens (n=200) were fabricated from self-cured acrylic resin, two 3D-printing resins (FormLabs, NextDent), and a milled material (TelioCAD). Randomization assigned specimens (n=10/group) to immersion solutions: artificial saliva, citric acid, heptane, coffee, and tea. Microhardness and color stability were evaluated. One-way and three-way ANOVA with Tukey's post hoc test analyzed the data. Results: Dietary solvents significantly reduced the surface microhardness of all tested materials (p< 0.05). Unpolished surfaces exhibited greater color changes compared to polished ones (p< 0.05) across all materials. Coffee and tea induced the most substantial reductions in hardness and the most significant color alterations (p< 0.05), whereas saliva and citric acid had minimal effects. Conclusion: Milled provisional restorations exhibited superior hardness and color stability. Dietary solvents significantly affected material properties over time, highlighting the importance of material selection for clinical applications. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the incorporation of zirconia/silver phosphate nanoparticles to develop experimental dental adhesives and to measure their physical and mechanical properties. The nanoparticles were synthesized by the sonication method, and the phase purity, morphological pattern, and antibacterial properties with Staphylococcus aureus and Pseudomonas aeruginosa were assessed. The silanized nanoparticles were incorporated (0, 0.15, 0.25, and 0.5 wt.%) into the photoactivated dimethacrylate resins. The degree of conversion (DC) was assessed, followed by the micro-hardness and flexural strength/modulus test. Long-term color stability was investigated. The bond strength with the dentin surface was conducted on days 1 and 30. The transmission electron microscopy and X-ray diffractogram confirmed the nano-structure and phase purity of the particles. The nanoparticles showed antibacterial activities against both strains and inhibited biofilm formation. The DC range of the experimental groups was 55–66%. The micro-hardness and flexural strength increased with the concentration of nanoparticles in the resin. The 0.5 wt.% group showed significantly high micro-hardness values, whereas a non-significant difference was observed between the experimental groups for flexural strength. The bond strength was higher on day 1 than on day 30, and a significant difference was observed between the two periods. At day 30, the 0.5 wt.% showed significantly higher values compared to other groups. Long-term color stability was observed for all the samples. The experimental adhesives showed promising results and potential to be used for clinical applications. However, further investigations such as antibacterial, penetration depth, and cytocompatibility are required. [ABSTRACT FROM AUTHOR]

Purpose: To compare the push-out bond strength (POBS) of two resin cement systems (total-etch versus self-etch) for cementing FRC (fiber-reinforced composite) posts in three different thermocycling aging periods (40,000; 20,000; and none) using thermocycling and three root levels (apical, middle, and coronal). Methods: 60 bicuspid single rooted natural teeth were endodontically treated and post spaces were prepared to receive a fiber-post (RelyX FiberPost) cemented with either total-etch (RelyX Ultimate) or self-etch (RelyX Unicem) cement. Teeth were randomly allocated into six groups (n= 10): Gl: Control (Ultimate without thermocycling); G2: Ultimate (20,000 cycles); G3: Ultimate (40,000 cycles); G4: Unicem without thermocycling; G5: Unicem (20,000 cycles); and G6: Unicem (40,000 cycles). POBS was determined by using a push-out test on a universal testing machine. Additionally, failure mode of each specimen was observed under a stereomicroscope at x40 magnification and scanning electron microscope (SEM) examination of selected samples. A nested general linear model was created for statistical significance P< 0.05. Post-hoc tests were carried out using pair-wise comparisons with a Bonferroni adjustment. Results: No significant differences were found on the bond strengths between the resin cements (P= 0.856). Regarding aging effect, bond strengths of the 40,000 cycle groups (G3/G6) were significantly lower than 20,000 cycle groups (G2/G5). In addition, the POBS of the specimens collected from the coronal third of the roots were significantly lower than specimens from the apical third regardless of the type of cement used. Regarding types of failures, adhesive failure (post/cement) was significantly higher in total-etch groups (G1-G3) than the self-etch groups (G4-G6). Adhesive failure (dentin/cement) was significantly higher in self-etch groups than the total-etch groups. [ABSTRACT FROM AUTHOR]