Non-contact ultrasound shear wave generation and wave speed measurement in soft tissue

This study investigates the feasibility of non-contact ultrasound shear wave generation and detection using a line focused air-coupled transducer and miniaturized fiber optic-based Sagnac system for soft tissue mechanical characterization. This paper focused on the measuring ultrasound shear wave velocity on a phantom tissue surface. Different phantoms with different stiffness were used as samples. The group velocity and phase velocity of the generated ultrasound surface wave were measured. The results showed that the proposed system was efficient in ultrasound shear wave generation and detection. It has potential applications in non-contact and non-invasive soft tissue mechanical properties characterizations

Segmentation of the metallic implants and tooth landmarks.

Segmentation of the metallic implants from the maxilla and marking of tooth landmarks in the sagittal, coronal, and transverse planes. Separated masks of each tooth were created individually.</p

Analysis of 3D STL models performed using the Rapidform software.

A. Landmarks were defined as follows: U6C, mesiobuccal crown cusp of the maxillary first molar; U6R, mesiobuccal root tip of the maxillary first molar; U3C, crown cusp of the maxillary canine; U3R, root tip of the maxillary canine; U2C, midpoint of the lateral incisor edge; U2R, root tip of the maxillary lateral incisor; U1C, midpoint of the central incisor edge; U1R, root tip of the maxillary central incisor; ANS, anterior nasal spine on model T2; and PNS, posterior nasal spine on model T2. B. A fitting transverse plane (plane 1) was built with points U6C and U1C on two sides of the T2 model; ANS-PNS-PNS’-ANS’ was defined as the sagittal plane (plane 2). C. U3Rp was the projection of U3R on plane 1, and U3C’, U3R’, and U3Rp’ were projections of U3C, U3R, and U3Rp on plane 2. D. Angle U3C’ U3R’ U3Rp’ was the sagittal angle of the canine.</p

Displacement of the landmarks and root length changes for each tooth.

<p>Displacement of the landmarks and root length changes for each tooth.</p

Imidazolium Salt Incorporated Poly(<i>N</i>‑vinylimidazole-<i>co</i>-ethylene glycol dimethacrylate) for Efficient Adsorption of Congo Red and Hg²⁺ from Aqueous Solution

Herein, imidazolium salt incorporated poly­(N-vinylimidazole-co-ethylene glycol dimethacrylate) was developed for adsorption of Congo Red (CR) and Hg2+ from aqueous solution. By the introduction of N-vinylimidazole and p-dichloroxylene on the skeletons, this polymer contained not only ionized imidazole moieties but also plenty of mesopores, endowing the polymer with excellent adsorption of CR and Hg2+. The maximum capacity at 298 K reached 503.0 and 240.0 mg/g, respectively. The Langmuir model described the equilibrium data well, and a chemical interaction in forms of electrostatic interaction, hydrogen bonding, and chelating interaction was involved in the adsorption with adsorption enthalpies of 9.99 and 17.28 kJ/mol, respectively. The adsorption was a fast process, and less than 20 min was sufficient to attain the equilibrium with pseudo-second-order rate constants of 4.003 × 10–3 and 9.830 × 10–4 g/(mg·min), respectively

Comparison of sagittal angle changes.

<p>Comparison of sagittal angle changes.</p

Implant superimposition for the adult sample.

<p>It was performed with the Dolphin software using the registration of four points: both endpoints of the two unloaded implants on the same side.</p

Linear changes (T1—T2) in landmarks in the vertical (X) and mesiodistal (Y) directions.

<p>Linear changes (T1—T2) in landmarks in the vertical (X) and mesiodistal (Y) directions.</p

Implant stability, determined by measuring the distances between the endpoints of two implants.

Implant stability, determined by measuring the distances between the endpoints of two implants.</p

Comparison of orthodontic tooth movement between adolescents and adults based on implant superimposition

<div><p>Objective</p><p>We compared tooth movement under maximum anchorage control with mini-screw implants in growing and non-growing patients.</p><p>Methods</p><p>In total, 15 adolescent (G1) and 19 adult (G2) patients with prognathic profiles were selected. All patients underwent first premolar extraction treatment with mini-screw implants for maximum anchorage control. Cone-beam computed tomography (CBCT) data were obtained immediately after implant placement (T1) and at the end of anterior tooth retraction (T2). Tooth movement and root length changes of the maxillary first molar, canine, and incisors were evaluated with three-dimensional models constructed using CBCT data obtained before and after orthodontic retraction through the superimposition of stable implants.</p><p>Results</p><p>Distal movement of the molar crown was observed in G2, but mesial movement was observed in G1. Mesial tipping of the first molar (1.82 ± 6.76°) was seen in G1 and distal tipping (4.44 ± 3.77°) was observed in G2. For the canines, mesial crown tipping (0.33 ± 4.99°) was noted in G1 and distal crown tipping (8.00 ± 5.57°) was observed in G2. In adults, the lingual inclinations of the lateral and central incisors were 11.91 ± 7.01° and 11.47 ± 6.70°, with 0.99 ± 1.22 mm and 1.08 ± 1.20 mm root retraction, respectively. In adolescents, the torque changes were smaller (lateral incisors, 8.25 ± 10.15°; central incisors, 9.82 ± 8.97°) and the root retractions were 0.31 ± 1.81 mm and 0.77 ± 1.59 mm, respectively. Less shortening of the central incisor roots occurred in adolescents than in adults.</p><p>Conclusions</p><p>Tooth movements, such as anchor molar angular change, the canine tipping pattern, and the amount of incisor retraction, differed between adolescents and adults treated using the same anchorage with mini-screw implants, bracket prescription, and <i>en masse</i> retraction method. Anchorage strength of the first molars, canine movement patterns, and incisor retraction ranges are not determined by the anchorage device alone; growth and alveolar limitations also play roles.</p></div