European Journal of Oral Sciences最新文献

This study examines how porcelain firing cycles and fabrication methods impact the microstructure and the marginal and internal fit of implant-cemented Co–Cr frameworks. Two fabrication processes for Co–Cr specimens were used: hard milling or soft milling. Each type of framework was then allocated to use either as-fabricated or as porcelain-fired. The microstructural analysis employed x-ray diffraction (XRD) and scanning electron microscopy with energy-dispersive x-ray spectroscopy (SEM/EDX). A total of ten Co–Cr frameworks were fabricated for each method, and discrepancies in margin and internal fit were evaluated using X-ray microtomography (micro-CT) before and after the porcelain firing. Statistical analysis was performed using two-way ANOVA and Tukey's multiple comparison tests (α = 0.05). The findings indicated a combination of γ-fcc and ε-hcp cobalt-based phases, with porcelain firing notably enhancing the ε-Co content, particularly among soft milled specimens. Soft milled specimens exhibited a diffuse presence of pores, while hard milled specimens revealed a random distribution of small pores. The soft milled specimens exhibited a significant reduction in discrepancies after the application of firing cycles. Although not statistically significant, the hard milled specimens also showed a trend toward reduced discrepancies post-firing. All subgroups maintained clinically acceptable marginal adaptation, with soft milled frameworks outperforming their hard milled counterparts in overall fit.

The mechanical properties and machinability of CAD/CAM materials are critical in determining their clinical applications. This study evaluated and compared the mechanical behavior and machinability of three composite-based blocks: Cerasmart (CS), Lava Ultimate (LU), and Grandio Blocs (GR), with a ceramic-based block, Initial LRF (IR). Flexural strength, flexural modulus, fracture toughness, and Vickers hardness were assessed following standardized ISO protocols. The machinability was tested using the Merlon fracture method (ISO 18675:2022), and machined margins were examined using scanning electron microscopy (SEM). One-way ANOVA was performed for statistical analysis (α = 0.05). GR exhibited the highest flexural strength among the tested materials, while IR showed significantly higher flexural modulus and Vickers hardness than the other materials. CS showed the lowest fracture toughness values. SEM observations revealed clear differences in surface quality after machining, with the ceramic block IR displaying inferior edge integrity compared with the composite-based blocks. All four materials demonstrated satisfactory machinability according to ISO standards. However, composite-based blocks exhibited better edge quality compared with the leucite-reinforced ceramic block. The findings indicate that composite-based restorative materials may result in better adaptation at the dental margins in posterior restorations, whereas ceramic materials present greater hardness, making them particularly suitable for enamel replacement.

This study investigates the effect of adding different amounts of n-ZnO to model resin-based composites on their hygroscopic characteristics. Six groups (n = 5) were formulated using Bis-GMA, TEGDMA, UDMA, inert barium glass powder, silica nanoparticles, and varying amounts of n-ZnO (0–5 wt.%). The photoinitiator system included camphorquinone, diphenyliodonium hexafluorophosphate, and ethyl 4-(dimethylamino) benzoate. Sorption, solubility, and hygroscopic expansion specimens were prepared following ISO 4049:2019 and immersed in water for 168 days. Sorption and solubility were assessed with an analytical balance, while hygroscopic expansion was measured using a laser scan micrometer. Zn²⁺ release was analyzed using ICP-MS (n = 3). Increasing n-ZnO concentrations significantly reduced sorption and solubility, with the control (0 wt.% n-ZnO) showing the highest values (28.7 and 2.1 µg/mm³) and the 2 wt.% n-ZnO group showing the lowest (27 µg/mm³, −0.4 µg/mm³). However, increasing the concentrations of n-ZnO significantly increased the hygroscopic expansion. The volumetric expansion for the lowest (control) and highest (n-ZnO at 3 wt.%) was 1.63% and 1.87%, respectively. ICP-MS revealed progressively higher Zn²⁺ release with increasing n-ZnO concentration, peaking at 675.1 ppb in the 5 wt.% group. Overall, n-ZnO reduced sorption and solubility while increasing expansion and Zn²⁺ release, with all formulations meeting ISO 4049 standards.

This study compared the bond strength of a bioceramic sealer and an epoxy resin-based sealer to root canals under different drying protocols. Seventy-two single-rooted teeth were allocated to one of three root canal drying protocols: dry; slightly moist; and wet. For each drying protocol two endodontic sealers were used: AH Plus Bioceramic Sealer (AHPB) or AH Plus (AHP) (n = 12 per combination of sealer and drying protocol). Slices of the root thirds were obtained and subjected to an immediate (1 week) and an after aging (10,000 thermal cycles) push-out test. Failure mode analysis and adhesive interface analysis were also carried out. Statistical analyses included two-way ANOVA, Tukey's post hoc test, t-test, and chi-square test. The immediate bond strength of AHP was higher than that of AHPB when the canal was slightly moist or wet. Also, a better marginal adaptation of the AHP to the root canal walls was found than that seen for AHPB. Comparing the different drying protocols within the same endodontic sealer, no differences were observed for AHP or AHPB. After aging, the bond strength decreased for AHP wet and for AHPB dry groups. Failure modes were similar among the groups. The AHP sealer demonstrated superior adhesive performance compared with AHPB, showing better results in dry root canals.

The rising use of 3D-printed temporary prostheses calls for a deeper understanding of microbial adhesion to these prostheses, a topic that remains insufficiently explored. This study evaluates the surface properties and microbial adhesion of four types of temporary materials manufactured by different methods: two conventionally produced materials—poly(ethyl methacrylate) (PEMA) and bis-acryl composite (BA)—and two digitally fabricated materials—poly(methyl methacrylate) (PMMA, CAD/CAM milled) and difunctional methacrylate resin (3Dresin, 3D printed). A total of 120 specimens (n = 30 per material) were prepared for surface roughness, contact angle, and microbial adhesion tests using Staphylococcus aureus, Streptococcus mutans, and Candida albicans. Additionally, 12 separate specimens (one per microorganism for each material) were prepared for scanning electron microscopy (SEM) analysis. The results revealed that BA and PEMA had higher contact angles than both PMMA and 3Dresin, with BA showing the highest surface roughness. S. aureus exhibited the highest adhesion across all materials. Surprisingly, 3Dresin, despite its low surface roughness, demonstrated the highest microbial adhesion. No statistically significant correlation was found between CFU counts and either surface roughness or contact angle. The study highlights that conventional materials are more hydrophobic than digitally produced ones, suggesting that 3Dresin materials may pose a higher risk of microbial colonization and biomaterial-associated infections.

Stem cells from the apical papilla (SCAP) are essential for regenerative endodontic treatment. Although mineral trioxide aggregate (MTA) and Biodentine are widely used in regenerative endodontic treatment procedures, their effects on SCAP remain unclear. This study investigated the impact of ProRoot MTA and Biodentine on SCAP viability and mineralization in the presence of Enterococcus faecalis under aerobic and anaerobic environments. Stem cells from the apical papilla were isolated from three healthy donors and exposed to three different surface area-to-volume (SA:V) ratio extracts of ProRoot MTA and Biodentine for 21 days in aerobic or anaerobic conditions. Cell viability was assessed using a neutral red cytotoxicity assay, and mineralization was evaluated by measuring alkaline phosphatase (ALP) activity. No significant differences between ProRoot MTA and Biodentine regarding SCAP viability were detected; however, increased cytotoxicity was found (for both ProRoot MTA and Biodentine) at the highest SA:V ratio of extract used. Oxygen availability, as well as variability in responses of SCAP from the different donors, resulted in greater variation of ALP levels than did type of material. Both ProRoot MTA and Biodentine showed comparable effects on SCAP viability and mineralization, with high SA:V ratios of extracts resulting in increased cytotoxicity. Mineralization in SCAP is influenced by oxygen conditions and the presence of E. faecalis, elucidating the need for further in vivo studies to optimize regenerative endodontic treatment outcomes.

The aim of this systematic review was to investigate the effects of silver diamine fluoride (SDF) on dentin in permanent teeth. Eight databases (PubMed, SciELO, Scopus, EMBASE, Web of Science, Science Direct, LILACS, and Livivo) and three “gray literature” sources (Open Access Theses and Dissertations [OATD], Open Grey, and ProQuest) were used. Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines were followed, and methodology quality was assessed using the QUIN tool. The review included in vitro studies investigating the effect of 38% SDF on demineralized permanent dentin. The primary outcomes were findings from energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) approaches, while secondary outcomes included findings from hardness testing, micro-computed tomography (micro-CT), and scanning electron microscopy. From 16,630 results, 17 studies met the eligibility criteria. After treatment with 38% SDF, significant increases were observed in the levels of calcium (Ca) and phosphorus (P) in dentin. Higher mineral/matrix ratios and a significantly lower amide I/HPO²⁻ ratio were identified, using FITR, in groups treated with SDF. Restoration of dentin crystallinity in groups treated with SDF, with sharp peaks for silver chloride and silver, were shown using XRD. Micro-computed tomography revealed reduced lesion depth, while scanning electron microscopy showed smoother surfaces and partial occlusion of tubules. Risk of bias was moderate in 13 studies and high in four. Overall, 38% SDF reduces demineralization, preserves mineral content, increases the levels of Ca and P, and enhances mineral/matrix ratios, demonstrating potential for managing demineralization.

The aim of the study was to assess the effect of bulk material on the reliability and failure modes of narrow-diameter implants. Narrow implants (Ø3.5 × 10 mm - 11° internal conical connection) were manufactured from three different bulk materials: commercially pure titanium grade-IV (CP4), cold-worked titanium (CW), and 4Titude (4Ti), and were evaluated under fatigue testing. Eighteen samples per group were tested under step-stress accelerated life testing through 30° off-axis load application in mild, moderate, and aggressive loading profiles. The number of cycles and load at failure were used to calculate use-level probability curves and reliability for missions of 100,000 cycles up to 200 N, followed by fractographic analyses. Beta values suggested that damage accumulation dictated failures. Reliability analyses at 80, 120, and 150 N evidenced high reliability for narrow implants independent of bulk material. At 200 N, a decrease in reliability was observed for all groups (∼46%). Failure mode analysis depicted similar failures for all groups and comprised implant fracture, abutment fracture, and implant + abutment fractures. Narrow implants presented high reliability for physiologic masticatory forces in the anterior region. Characteristic strength, reliability, and failure modes were similar regardless of bulk material, suggesting that fatigue damage accumulation at thin wall implants dictated failure over bulk material strength.

We aimed to characterize the salivary proteomic profile and the salivary protein expression in children with and without early childhood caries (ECC) in order to identify salivary protein biomarkers for ECC. We recruited 56 children into the ECC (n = 28) and caries-free (n = 28) groups. Stimulated whole saliva was collected on ice, followed by protein analysis using a label-free proteomic technique. Moreover, we performed a multidisciplinary bioinformatic analysis. Proteomic analysis revealed significant between-group differences in the salivary protein expression profiles. Based on the protein–protein interaction network analysis and protein function identification, we identified L-lactate dehydrogenase as a potential biomarker. Accordingly, in a validation study, we performed an enzyme-linked immunosorbent assay to detect the differential expression of salivary L-lactate dehydrogenase between 20 preschool children with ECC and 19 caries-free children. The ECC children had significantly higher levels of L-lactate dehydrogenase than the caries-free children, which suggests its predictive utility for ECC. Taken together, our findings suggest that L-lactate dehydrogenase, as well as peroxiredoxin-5, glucose-6-phosphate-1-dehydrogenase, glutathione reductase, malate dehydrogenase, and talin-1, may be potential biomarkers of ECC.

We aimed to identify factors predicting toothbrushing less than twice daily at the age of 2 years. The data from the FinnBrain Birth Cohort Study of 506 mother–father pairs (with 506 children) were used. Logistic regression analyses were conducted of the outcome (brushing less than twice daily) at the age of 24 months. Independent variables were parental age, parental education, siblings in the household, use of childcare service, and information about whether the parents are divorced, as well as brushing of the child's teeth and the parents’ own teeth at 12 months with their first order interactions. More than one quarter of the parents reported brushing their child's teeth less than twice daily at the age of 2 years. The strongest predictor for brushing the child's teeth less than twice daily at the age of 24 months was brushing child's teeth less than twice daily at the age of 12 months; the effect was significantly stronger for those children whose fathers had low education than for those whose fathers had medium/high education. Other predictors were mother's and father's own brushing at 12 months, childcare at home, and mother's low education. To improve toothbrushing in young children, early intervention is needed in families where parents brush their own teeth less than twice daily and in families with low education.