Nanoparticles (NPs) have become a very exciting research avenue, with multitudinous applications in various fields, including the biomedical one, whereby they have been gaining considerable interest as drug carriers able to increase bioavailability, therapeutic efficiency and specificity of drugs. Epigenetics, a complex network of molecular mechanisms involved in gene expression regulation, play a key role in mediating the effect of environmental factors on organisms and in the etiology of several diseases (e.g., cancers, neurological disorders and cardiovascular diseases). For many of these diseases, epigenetic therapies have been proposed, whose application is however limited by the toxicity of epigenetic drugs. In this review, we will analyze two aspects of epigenetics in the field of NPs: the first is the role that epigenetics play in mediating nanotoxicity, and the second is the possibility of using NPs for delivery of “epi-drugs” to overcome their limitations. We aim to stimulate discussion among specialists, specifically on the potential contribution of epigenetics to the field of NPs, and to inspire newcomers to this exciting technology.

This scientific article investigates the mechanical properties of a novel three-dimensional-printing resin specifically designed for orthodontic aligners and compares it to other commonly used resins. The resin was made by blending two commercially available and certified resins to produce aligners with improved mechanical properties compared to each separate resin. The study examined the effect of the addition of NextDent Ortho Rigid resin on the mechanical properties of the specimens, more specifically analyzing the relationship between the amount of the added rigid resin and the mechanical properties of the specimens. The mechanical properties of the specimens and the nickel-titanium wires were analyzed using a three-point bending test setup. The results showed no statistically significant differences within the different groups of specimens. The study provides valuable insights into the potential of the resin to meet the mechanical demands of orthodontic treatments. It will contribute to the advancement of personalized orthodontic care through three-dimensional-printing technology. Blending commercially available and certified resins enables orthodontic practitioners to select the most suitable resin for each case, providing better outcomes for patients and increasing the efficiency of the treatment process. Further research and evaluation would be required to determine the suitability of the blended resin for orthodontic treatments.

The purpose of this systematic review is to analyze the dentoalveolar changes resulting from the use of clear aligners in the treatment of transverse maxillary deficiency among growing children in the mixed dentition stage. An electronic literature search was carried out using the following databases: PubMed, Scopus, Cochrane Library, Embase, and Web of Science. The review protocol was prospectively registered in the PROSPERO database. Eligible studies included children aged 6 to 12 years in the mixed dentition period, presenting with erupted maxillary first molars and a transverse deficiency of the maxilla, and undergoing treatment with Invisalign^® First aligners. The review encompassed various study types including retrospective and prospective designs, randomized controlled trials, preliminary studies, and case series. Two independent reviewers conducted the data extraction process. The quality of evidence was assessed using the GRADE approach. Except for studies by Bruni et al., the risk of bias in selected articles was visually summarized in a traffic light plot using the robvis tool, following the ROBINS-I methodology. For the studies by Bruni et al., a separate visual representation was created using robvis with the RoB2 evaluation framework, prepared by the authors S.E.I. and C.A. In total, 14 studies were included in the final synthesis, selected from 265 records retrieved through electronic searches and an additional 36 identified via manual screening. Several parameters were considered in order to assess dentoalveolar expansion: intercanine width, intercanine transpalatal width, intercanine dentoalveolar width, first and second interdeciduous molar width, first and second interpremolar width, first and second interdeciduous molar transpalatal width, first intermolar width, first intermolar mesial, distal, and transpalatal width, molar inclination, arch depth, and arch perimeter, and intermolar dentoalveolar width. An improvement was recorded in all parameters. The studies comparing treatment with Invisalign^® First clear aligners and rapid maxillary expander highlighted that these both determined statistically significant differences compared to the natural growth group. Treatment with Invisalign^® First in mixed dentition proved to be very effective for dentoalveolar expansion of the maxillary arch, with good control of the crown angulation of the upper first molar and an increase in the palatal area similar to RME, compared to pre-treatment or to the natural growth group. It could represent an effective and comfortable alternative to the traditional rapid maxillary expander treatment. However, further high-quality studies are required to support our current observations and verifying the stability of treatment outcomes on a long-term basis.

This study presents a scanning electron microscopy analysis of a failed PEEK retainer in an orthodontic patient. After 15 months of use, the patient reported a gap opening between teeth 41 and 42. The PEEK retainer was removed and sent for electron microscope analysis. To investigate the failure, scanning electron microscopy was employed to assess the microstructure and composition of the retainer at various magnifications. These findings suggest that the failure of the PEEK retainer was multifaceted, implicating factors such as material defects, manufacturing flaws, inadequate design, environmental factors, and patient-related factors. In conclusion, this scanning electron microscopy analysis offers valuable insights into the failure mechanisms of PEEK retainers in orthodontic applications. Further research is necessary to explore preventive strategies and optimize the design and fabrication of PEEK retainers, minimizing the occurrence of failures in orthodontic practice.

Directly 3D-printed aligners (DPAs) have recently emerged as a promising development in orthodontics, offering greater design flexibility and in-office manufacturing. However, their biological safety remains incompletely characterised, particularly regarding the release of micro- and nanoplastics (MNPs) during clinical use. This study evaluated the in vitro cytocompatibility of eight orthodontic aligner materials, including thermoformed systems, directly 3D-printed resins, and a polyamide-12 (PA-12) device, using MTT cell-viability assays on human dental pulp stem cells (hDPSCs). Standardised specimens were prepared according to manufacturer-recommended protocols, while MNP suspensions were generated by controlled abrasion and sonication. Cells were exposed to material eluates at concentrations of 500, 1000, and 5000 ng/100 µL for 24 to 96 hours. Cell viability and morphological analyses revealed marked material-, dose-, and time-dependent differences. Thermoformed materials and the polyamide-12 system generally exhibited more stable profiles, with viability frequently above 70% and preserved cell morphology. A subset of materials showed non-linear responses suggestive of a hormetic-like effect. By contrast, several directly 3D-printed resins showed greater reductions in viability, approaching moderate cytotoxicity at higher concentrations and longer exposure. Within the limitations of this in vitro study, thermoformed materials and polyamide-12 showed more consistent cytocompatibility than some directly printed materials. These findings highlight the need for systematic biocompatibility evaluation of orthodontic aligner materials and indicate that adherence to standardised post-curing protocols and rigorous material qualification workflows is essential to minimise potential biological risks during clear aligner therapy.

The calcified tissues of vertebrates are essentially represented by bone, cartilage, dentin and calcified tendons. In all these tissues a major hallmark of mineralization is the deposition of the inorganic phase on a pre-existing collagen template, but evident differences exist among these materials and the molecular details of the process are still incompletely understood. In this study, the ultrastructural aspects of the mineral phase of these tissues were investigated by means of high-resolution scanning electron microscopy (HR-SEM) after low-temperature thermal deproteination, a technique allowing a direct, unrestricted visualization of the mineral component. Each tissue showed distinctive features. In most cases, calcification proceeds in a discontinuous way through the formation of clumps or clusters of mineralized tissue; in all cases, except cartilage, the mineral phase shows an evident relationship with the layout and/or the D-period of the collagen fibrils. Our results highlight the peculiar aspect of the mineralization process in the cartilage with respect to the other tissues, all of them containing collagen type I instead of type II, and suggest that a different molecular mechanism may be at work. It is still unclear whether and how this may be related to the content, exclusive of cartilage, of collagen type II. The identification of the tissue-specific features exhibited by cartilage versus those shared by all the other three tissues, although from different species, requires further research on physiological calcification.