Background: This study aimed to assess the impact of methacrylate-functionalized polyhedral oligomeric silsesquioxanes dispersed in nanosilica (MA/Ns-POSS) on the mechanical properties of light-curable dental resins and composites. The primary goal was to evaluate how different concentrations of MA/Ns-POSS (0.5–20 wt.%) affect the hardness, flexural strength, modulus, diametral tensile strength, polymerization shrinkage stress, and degree of conversion of these materials. Methods: A mixture of Bis-GMA, UDMA, TEGDMA, HEMA, and camphorquinone, with a tertiary amine as the photoinitiator, was used to create resin and composite samples, incorporating 45 wt.% silanized silica for the composites. Hardness (Vickers method, HV), flexural strength (FS), and flexural modulus (E_f) were assessed using three-point bending tests, while diametral tensile strength (DTS) polymerization shrinkage stresses (PSS), and degree of conversion (DC) analysis were analyzed for the composites. Results: The results showed that resins with 10 wt.% MA/Ns-POSS exhibited the highest E_f and FS values. Composite hardness peaked at 20 wt.% MA/Ns-POSS, while DTS increased up to 2.5 wt.% MA/Ns-POSS but declined at higher concentrations. PSS values decreased with increasing MA/Ns-POSS concentration, with the lowest values recorded at 15–20 wt.%. DC analysis also showed substantial improvement for 15–20 wt.% Conclusion: Incorporating MA/Ns-POSS improves the mechanical properties of both resins and composites, with 20 wt.% showing the best results. Further studies are needed to explore the influence of higher additive concentrations.

Methacrylate-POSS (M-POSS) is a novel organic–inorganic additive shown to reinforce dental composites and reduce polymerization shrinkage. This study aimed to evaluate the influence of M-POSS addition (0.5, 2, 10, or 15 wt.%) on the mechanical properties of an experimental polymer matrix (bis-GMA/UDMA/TEGDMA/HEMA = 35/35/20/10 wt.%) and a dental resin composite (45 wt.% silanized silica as filler). Vickers hardness (HV), three-point bending strength (FS), diametral tensile strength (DTS), and shrinkage stress generated during polymerization were studied. The results show HV values between 16 and 18 compared to 15 ± 1 in the control group. Hardness in the control composite was 34 ± 4, and after modification, it showed similar or slightly lower values between 32 and 35. FS increased from 90 ± 4 MPa before modification to 100 ± 5 MPa for 2 wt.% M-POSS, and then decreased to 78 ± 5 MPa for materials containing 15 wt.% M-POSS. FS of composites were within the range of 61–77 MPa, with a similar tendency in variation to that of matrices. DTS values decreased after M-POSS addition, from 37 ± 4 MPa before modification to 31–33 MPa after modification. Flexural modulus decreases after modification, both for matrices and composites. The morphology of composites with >10 wt. % M-POSS showed visible surface irregularities. In conclusion, M-POSS affects matrix hardness, resulting in an increase in HV. The addition of M-POSS also increases FS values of the matrix, but only up to a certain concentration. However, the introduction of M-POSS does not significantly affect the HV or bending strength of the composites. Although DTS values decreased, this change was not statistically significant. Finally, contraction stress was significantly reduced for groups containing 2 wt.% and 10 wt.% M-POSS, representing an anticipated and promising improvement.

Background/Objectives: The loss of orthodontic microimplants is a common clinical complication that significantly disrupts the continuity of malocclusion treatment. Despite increasing clinical use of microimplant reinsertion, the factors influencing its success remain unclear. The aim of this exploratory systematic review was to examine the available literature regarding clinical outcomes related to the retention of orthodontic microimplants following their reinsertion. Methods: Studies that assessed the success of orthodontic microimplant reinserted were included in the review. Searches were conducted on 27 September 2025, in the following databases: BASE (Bielefeld Academic Search Engine), PubMed, Scopus, and EMBASE. The ROBINS-I (Risk of Bias in Non-randomized Studies—of Interventions) tool was used to assess the risk of bias. Due to heterogeneity of included studies, a narrative synthesis was performed. Results: Four of the 577 studies were included in the review. A total of 305 microimplants were reinserted in 276 patients. The overall success rate ranged from 44.16% to 66%. Analysis indicated a significantly higher success rate in the maxilla (up to 68.60%) compared to the mandible (lowest 36.84%). Furthermore, a narrative synthesis suggests better clinical outcomes for 8 mm long microimplants compared to 6 mm ones, as well as reduced reinsertion success in areas with high cancellous bone density. Regarding the modification of the insertion site, the current data are contradictory; while some studies indicate significant benefits from changing the site (e.g., to the midpalatal suture), others show no statistical difference compared to reinsertion at the same site. Overall, the evidence remains limited and heterogeneous. Conclusions: The current review of the literature on the success of reinsertion of orthodontic microimplants is subject to a high risk of misinterpretation, due to the limited amount of data and the risk of unidentified confounding factors. Further standardized clinical trials are needed to develop unified protocols for these procedures. Other: The review was prospectively registered with the Open Science Framework (OSF); osf.io/tbj2s.

Multilayer zirconia ceramics with a high yttrium content represent an important step in the development of zirconia-based materials, improving the aesthetics of full-contour restorations while maintaining acceptable mechanical properties. The aim of this study was to review the literature on the...