Search Results (4)

This study aimed to assess skeletal and upper airway modifications induced by the Twin Block appliance in patients with Class II malocclusion due to mandibular retrusion, using two-dimensional imaging techniques. A total of 11 patients (6 males, 5 females) were included and stratified into two groups (Pre-Peak and Peak) based on skeletal maturity evaluated through the cervical vertebral maturation (CVM) method. Lateral cephalometric radiographs were obtained at the beginning (T0) and end (T1) of treatment and analyzed using DeltaDent software. The appliance was worn full-time, except during meals and oral hygiene procedures, with monthly follow-ups. Significant changes were observed between T0 and T1 across the sample. Comparison between groups revealed statistically significant differences only in the H-C3a1 and vertical height (th) parameters (p < 0.05). In conclusion, the Twin Block appliance proved effective in enhancing mandibular and dental positioning, while also exerting a favorable influence on upper airway development. Full article

Aim: Polyurethane-based aligners, created through photoinitiated free-radical polymerization, have been the subject of numerous studies focusing solely on their mechanical properties. In contrast, we investigate their thermomechanical properties, which are crucial for their efficacy. This paper aims to investigate the effects of different UV light exposure durations on the complex modulus of elasticity, tan delta, glass transition temperature, and the degree of conversion (DC). Methods: Aligners were printed using Tera Harz TC-85 and NextDent Ortho Flex resin with specific exposure times (2, 2.4, 3, 4, and 4.5 s for Tera Harz; 5, 6, 7, and 8 s for NextDent) and processed per manufacturer guidelines. The degree of conversion was analyzed using Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy, while Dynamic Mechanical Analysis (DMA) characterized the mechanical properties (complex modulus and tan delta) and the glass transition. Results: Tera Harz TC-85 showed a higher degree of conversion (90.29–94.54%), suggesting fewer residual monomers, which is potentially healthier for patients. However, its lower glass transition temperature (35.60–38.74 °C) might cause it to become rubbery in the mouth. NextDent Orto Flex, with a higher storage modulus (641.85–794.55 MPa) and Tg (49.36–50.98 °C), offers greater rigidity and stability at higher temperatures (greater than temperature in the oral cavity), ideal for orthodontic forces, though its lower degree of conversion raises health concerns. Conclusions: Tera Harz TC 85 generally achieves higher DC and more stable polymerization across different UV exposure times than NextDent Orto Flex. Optimal polymerization times significantly impact both the mechanical and thermal properties of these dental resins, with NextDent showing optimal properties at 7 s and Tera Harz benefiting from both very short and extended exposure times. Full article

Achieving precise control over the motion position and attitude direction of magnetic microrobots remains a challenging task in the realm of microrobotics. To address this challenge, our research team has successfully implemented synchronized control of a microrobot’s motion position and attitude direction through the integration of electromagnetic coils and permanent magnets. The whole drive system consists of two components. Firstly, a stepper motor propels the delta structure, altering the position of the end-mounted permanent magnet to induce microrobot movement. Secondly, a programmable DC power supply regulates the current strength in the electromagnetic coil, thereby manipulating the magnetic field direction at the end and influencing the permanent magnet’s attitude, guiding the microrobot in attitude adjustments. The microrobot used for performance testing in this study was fabricated by blending E-dent400 photosensitive resin and NdFeB particles, employing a Single-Layer 4D Printing System Using Focused Light. To address the microrobot drive system’s capabilities, experiments were conducted in a two-dimensional and three-dimensional track, simulating the morphology of human liver veins. The microrobot exhibited an average speed of 1.3 mm/s (movement error ± 0.5 mm). Experimental results validated the drive system’s ability to achieve more precise control over the microrobot’s movement position and attitude rotation. The outcomes of this study offer valuable insights for future electromagnetic drive designs and the application of microrobots in the medical field. Full article

Cone-beam computed tomography (CBCT) allows for more accurate 3D study of the craniofacial region and the development of a very precise treatment plan. The present pilot study aims to evaluate the skeletal outcomes of the rapid maxillary expander (RME) on the sagittal, transverse and vertical planes in growing patients subjected to CBCT at T0 and T1, and to compare the results from two different programs. The effects of the RME are monitored in 11 patients who were subjected to CBCT at T0, before the expansion, and at T1, 6 months after the end of the RME therapy. The results obtained are evaluated using two programs: Simplant and Delta-Dent. All of the analyses were performed by the same operator. Both programs reported statistically significant differences between the pre- and post-expansion values of the parameters on the transverse plane. On the vertical plane, only posterior facial height showed a statistically relevant variation. Both programs underlined a discrepancy between the pre- and post-expansion infraorbital and mental foramina distance values; however, this difference was considered statistically significant by Delta-Dent, and not by Simplant. CBCT is a reliable and effective tool for orthodontic diagnosis and treatment planning. Both of the evaluated programs are efficient in tridimensional cephalometric analysis. Full article