The mechanical properties of 3D printed denture base resin incorporating essential oil microcapsules.

Purpose: The aim of this study was to investigate the mechanical properties of three-dimensional (3D) printed denture base resin incorporating microcapsules containing plant essential oils. Materials and Methods: Denture base specimens containing up to 3% w/v essential oil microcapsule powders (MCPs), i.e., eucalyptus, geranium, lavender, menthol, and tea tree, in two resins (Detax and NextDent 3D+) were 3D printed using two printers (Asiga and NextDent 5100). The dispersion and interaction of the MCPs in the resin were assessed by SEM while the mechanical properties of the incorporated denture base including flexural strength (MPa), flexural modulus (MPa), Vickers hardness (VHN), and surface roughness (Ra) were also subsequently evaluated. Statistical analysis of any differences in mean values was determined using a two-way ANOVA with Tukey's post hoc testing (α = .05). Results: The spherical shape of the MCPs was maintained during the mixing and polymerization/printing process. However, the Detax-Asiga group showed significant agglomeration of the MCPs even at the lowest MCP concentration levels (0.5% w/v). Overall, as the microcapsule concentration increased, the mean flexural strength decreased, though the menthol MCP groups remained compliant with the ISO standard. The flexural modulus and harness remained relatively unchanged, and the flexural modulus complied with the ISO standard regardless of the MCP concentration. Surface roughness increased with the addition of the MCPs but also remained below that required for clinical acceptance. Conclusion: Incorporation of microencapsulated plant essential oils into 3D printed denture base resin was successfully achieved. While incorporation negatively influenced flexural strength and surface roughness, little effect on flexural modulus and Vickers hardness was demonstrated.

Tracing the toxic ions of an endodontic tricalcium silicate-based sealer in local tissues and body organs.

BACKGROUND: This study aimed to track the toxic ions released by MTA Fillapex, BioRoot RCS, and an experimental tricalcium silicate-based sealer (CEO) into local and distant tissues as well as to investigate their potential adverse effects. In addition, the chemical constituents of the sealers were also evaluated. The main components of the dry powders, pastes, and mixed sealers were characterized. MATERIAL AND METHODS: Dry powder and sealer discs were each set for 72 h and their main components were characterized by energy dispersive X-ray spectroscopy. Polyethylene tubes filled with sealers were used to measure silicon and calcium ions. Polyethylene tubes filled with sealers or empty tubes were implanted into the dorsal connective tissue of Wistar rats. On days 7, 15, 30, and 45, the animals were euthanized and their brains, livers, kidneys, and subcutaneous tissues were removed and processed to determine the concentrations of chromium, cobalt, copper, lead, iron, magnesium and nickel using an inductively coupled plasma optical emission spectrometer. RESULTS: The main compounds in all sealers were carbon, oxygen, silicon, and calcium. MTA Fillapex release more Si while highest levels of Si were found in presence of BioRoot. The release of Si and Ca ions promoted by MTA Fillapex raise by time. No traces of cobalt, chromium, or magnesium were detected in any tissue. Irrespective of the sealer, no traces of copper and lead were found in the subcutaneous tissue; however, they were observed in the organs. The highest concentration of iron was identified in the liver. All sealers exhibited similar nickel traces in the brain, kidney, and liver except for MTA Fillapex, which demonstrated levels higher than CEO in the subcutaneous tissue on day 7. Tracing nickel ions over time revealed that lowest concentrations were found in subcutaneous tissue. CONCLUSION: Taken together, our data demonstrate that CEOs have chemical compositions similar to those of other commercial sealers. Furthermore, none of them exhibited a threat to systemic health. Moreover, the minimal amounts of iron and nickel detected were not related to the sealers.

The impact of the use of magnifying dental loupes on the performance of undergraduate dental students undertaking simulated dental procedures.

OBJECTIVES: This study aimed to evaluate the impact of the use of magnification (2.5x dental loupes) for third-year dental students in simulated endodontics and fixed prosthodontics assessments compared to those using no magnification. METHODS: Upon institutional review board exemption, third-year dental students were assessed during endodontics and fixed prosthodontics exams in the simulation laboratory. The endodontic group (n = 93) consisted of students who made an endodontic access preparation on a plastic lower left first molar (Nissan). The prosthodontic group (n = 86) consisted of students who made porcelain fused to metal preparation (PFM) on a plastic lower right first molar mounted on an acrylic lower jaw model (Columbia Dentoform). The impact of the use of dental loupes was evaluated. Assessment of the tasks was undertaken by experts-calibrated, blinded examiners-using a standardized marking rubric for each task. The statistical analysis included Chi-square test, one-way ANOVA, and Logistic regression. The level of significance adopted was 5%. RESULTS: Students' preparations using magnification were better compared with those without magnification. Students using magnification had a significantly higher pass rate than those not using magnification in both endodontic and prosthodontic groups (P < 0.05). CONCLUSIONS: In conclusion, third-year dental students who used loupes in the endodontics and prosthodontics simulation laboratory had significantly higher scores at the assessments.

Endodontic retreatment of an autotransplanted lower first premolar: a case report.

A 24-year-old female with no contributory medical history had been treated by orthodontic alignment and transplantation of the lower left first premolar to the upper left first premolar site to correct for congenitally missing upper premolars. Subsequently, the transplanted premolar was treated by conventional endodontics and apical surgery for persistent periapical periodontitis over a span of 12 years. A combination of conventional endodontic retreatment and periapical surgery resulted in periapical healing. This case outlines the need for careful preoperative case assessment.