Objective: Three-dimensional (3D) printing technology represents a novel method for manufacturing aligners. The aim of the present study was to assess the in-vitro cytotoxicity of 3D-printed aligners using different post-polymerisation conditions. Materials: Aligners were printed using the same 3D-print resin (TC-85DAC, Graphy, Seoul, Korea) and printer (AccuFab-L4D, Shining 3D Tech. Co., Hangzhou, China), followed by different post-curing procedures. Six aligners were post-polymerised for 14 min using the Tera Harz Cure and a nitrogen generator curing machine (THC2, Graphy, Seoul, Korea) (P1). A further six aligners were post-cured for 30 min on each side using the Form Cure machine (FormLabs Inc, Somerville, USA) (P2). The aligners were cut into smaller specimens (2 mm×2 mm) and sterilised at 121°C. The specimens were placed in 96-well plates containing Dulbecco’s Modified Eagle’s Medium (DMEM) at 37° for 7 or 14 days. The viability of MC3T3E-1 pre-osteoblasts cultured with DMEM was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The optical density of each cell culture was measured to assess cell viability, following which the data were statistically analysed using two-way and one-way ANOVA (α = 0.05). Results: The comparison of cytotoxicity revealed statistically significant differences between post-curing procedures and MTT timings ( P < 0.001). After 7 and 14 days, the cell viability of P2 was significantly reduced compared to P1 and the control groups ( P < 0.001), while P1 showed no significant differences compared to the controls. Overall, P2 post-curing exhibited moderate cytotoxicity, while P1 post-polymerisation was highly biocompatible. Conclusions: Different post-curing procedures may affect the in-vitro cytotoxicity of 3D-printed aligners. Clinicians should adhere to the manufacturer’s recommendations when using 3D-print resin.

Teeth include mesenchymal stem cells (MSCs), which are multipotent cells that promote tooth growth and repair. Dental tissues, specifically the dental pulp and the dental bud, constitute a relevant source of multipotent stem cells, known as dental-derived stem cells (d-DSCs): dental pulp stem cells (DPSCs) and dental bud stem cells (DBSCs). Cell treatment with bone-associated factors and stimulation with small molecule compounds are, among the available methods, the ones who show excellent advantages promoting stem cell differentiation and osteogenesis. Recently, attention has been paid to studies on natural and non-natural compounds. Many fruits, vegetables, and some drugs contain molecules that can enhance MSC osteogenic differentiation and therefore bone formation. The purpose of this review is to examine research work over the past 10 years that has investigated two different types of MSCs from dental tissues that are attractive targets for bone tissue engineering: DPSCs and DBSCs. The reconstruction of bone defects, in fact, is still a challenge and therefore more research is needed; the articles reviewed are meant to identify compounds useful to stimulate d-DSC proliferation and osteogenic differentiation. We only consider the results of the research which is encouraging, assuming that the mentioned compounds are of some importance for bone regeneration.

Irisin is a recently discovered cytokine, better known as an exercise-induced myokine, produced primarily in skeletal muscle tissue as a response to exercise. Although the skeleton was initially identified as the main target of Irisin, its action is also proving effective in many other tissues. Physical activity determines a series of beneficial effects on health, including the possibility of counteracting the damage that is caused by arthritis to the cartilage of people suffering from osteoarthritis. Nevertheless, up to now, the studies that have taken into consideration the possible involvement of Irisin on the well-being of cartilage tissue are particularly limited. In this study, we postulated that the protective effect of physical activity on cartilage tissue may depend on the paracrine action of Irisin secreted during exercise; therefore, we analyzed the effects of Irisin, in vitro, on chondrogenic differentiation. To achieve this goal, three-dimensional cultures of commercially available human articular chondrocytes (HACs) were treated with the molecule under study. Our results revealed new crosstalk mechanisms between muscle and cartilage tissue. Furthermore, the confirmation of Irisin ability to induce chondrogenic differentiation could favor the development of exercise-mimetic drugs, with application relevance for patients who cannot perform physical activity.

Teeth include mesenchymal stem cells (MSCs), which are multipotent cells that promote tooth growth and repair. Dental tissues, specifically the dental pulp and the dental bud, constitute a relevant source of multipotent stem cells, known as dental-derived stem cells (d-DSCs): dental pulp stem cells (DPSCs) and dental bud stem cells (DBSCs). Cell treatment with bone-associated factors and stimulation with small molecule compounds are, among the available methods, the ones who show excellent advantages promoting stem cell differentiation and osteogenesis. Recently, attention has been paid to studies on natural and non-natural compounds. Many fruits, vegetables and some drugs contain molecules that can enhance MSC osteogenic differentiation and therefore bone formation. The purpose of this review is to examine research work over the past 7 years that has investigated two different types of MSCs from dental tissues that are attractive targets for bone tissue engineering: DPSCs and DBSCs. We focused on articles hypothesizing the identification and study of compounds that induce proliferation and osteogenic differentiation of the two d-DSC populations, representing an interesting issue for regenerative medicine. The reconstruction of bone defects in fact is still a challenge for personalized medicine.

Introduction. Congenital platelet disorders constitute a heterogeneous group of primary hemostatic defects that are often difficult to diagnose without an integrated approach that includes functional testing. We report the case of a child with suspected Glanzmann thrombasthenia, in whom a novel variant of the RasGRP2 gene (NM_001098671.2) was identified that cosegregates with the clinical phenotype.Methods. An 8-year-old boy, presenting with recurrent epistaxis and bruising and without a significant family history, was evaluated at our center. Initial tests showed normal PT and aPTT and impaired platelet function (PFA-100), suggesting a platelet disorder such as Glanzmann’s thrombasthenia. However, the absence of aggregation tests and flow cytometric analysis prevented a definitive differential diagnosis. To identify the genetic cause and confirm the suspected diagnosis, clinical exome sequencing (6,600 genes) was performed using the NextSeq 550 platform (Illumina). Bioinformatic analysis included filtering based on allele frequency (