To improve the accuracy of bracket placement in vivo, a protocol and device were introduced, which consisted of operative procedures for accurate control, a computer-aided design, and an augmented reality–assisted bracket navigation system. The present study evaluated the accuracy of this protocol. Methods: Thirty-one incisor teeth were tested from four participators. The teeth were bonded by novice and expert orthodontists. Compared with the control group by Boone gauge and the experiment group by augmented reality-assisted bracket navigation system, our study used for brackets measurement. To evaluate the accuracy, deviations of positions for bracket placement were measured. Results: The augmented reality-assisted bracket navigation system and control group were used in the same 31 cases. The priority of bonding brackets between control group or experiment group was decided by tossing coins, and then the teeth were debonded and the other technique was used. The medium vertical (incisogingival) position deviation in the control and AR groups by the novice orthodontist was 0.90 ± 0.06 mm and 0.51 ± 0.24 mm, respectively (p < 0.05), and by the expert orthodontist was 0.40 ± 0.29 mm and 0.29 ± 0.08 mm, respectively (p < 0.05). No significant changes in the horizontal position deviation were noted regardless of the orthodontist experience or use of the augmented reality–assisted bracket navigation system. Conclusion: The augmented reality–assisted bracket navigation system increased the accuracy rate by the expert orthodontist in the incisogingival direction and helped the novice orthodontist guide the bracket position within an acceptable clinical error of approximately 0.5 mm.

Osteoclast differentiation is crucial for orchestrating both tooth movement and the maintenance of bone density. Therefore, the current study sought to explore the impact of low-level laser therapy (LLLT) on osteoclast differentiation, functional gene expression, molecular signaling pathways, and orthodontic tooth movement in clinical settings. The RAW 264.7 cell line served as the precursor for osteoclasts, and these cells underwent irradiation using a 808-nm LLLT. Osteoclast differentiation was assessed through tartrate-resistant acid phosphatase (TRAP) staining. Functional gene expression levels were evaluated using real-time quantitative polymerase chain reaction (RT-qPCR) while signaling molecules were examined through Western blot analysis. In the clinical study, 12 participants were enrolled. Their tooth movement was monitored using a TRIOS desktop scanner. Bone density measurements were conducted using Mimics software, which processed cone-beam computed tomography (CBCT) images exported in Digital Imaging and Communications in Medicine (DICOM) format. We found that LLLT effectively promoted receptor activator of nuclear factor-κB ligand (RANKL)-dependent osteoclast differentiation and the expression of osteoclast functional genes, including matrix metallopeptidase 9 (MMP9), nuclear factor of activated T-cells cytoplasmic 1(NFATc1), tartrate-resistant acid phosphatase (TRAP) and cathepsin K (CTSK) in RAW264.7 cells. Clinically, the cumulative tooth movement over 90 days was significantly higher in the laser group than in the control group. Our research demonstrates that LLLT not only significantly promotes osteoclast differentiation but is also a valuable adjunct in orthodontic therapy.

Absolute anchorages proved to be very effective for orthodontic tooth movements. We used a 3D digitizer to record each tooth on pre-treatment diagnostic and post-treatment predictive setup models and then 3D coordinate system conversion was performed to make the coordinate values comparable. An arithmetic calculation of vector and moment based on the orthodontic forces and the tooth displacement under preliminary premises undertaken to decide the most favorable pOsition and number for absolute anchorages. Position-For two-dimensional and three-dimensional calculations, the most appropriate positions for absolute anchorages should theoretically be on the line of resultant force (2D) and the plane (3D) where the total moment effect tends to be zero. Number-As for the number of the absolute anchorages needed, it depends on the number of target teeth. Different combinations of target teeth provide different sets of results.

An adult female (35 years old) came for orthodontic consultation with a chief complaint of poor dental alignment with protruded mandible. Clinical findings revealed that Class III malocclusion with functional anterior crossbite. Low Hysteresis Improved Super-elastic TieNi alloy wire (ISW), developed by Tokyo Medical and Dental University with ISW curve applied over upper arch for flaring out the upper anterior tooth. MEAW technique applied on lower arch to correct a negative overjet. Treatment was completed within 41 months and patient was pleased with the improvement of appearance and dental alignment.

A 20-year-old male adult came to the clinic with a chief complaint of poor dental alignment. Clinical examination had revealed Skeletal Class III with an upper right buccally positioned high canine, anterior crowding, midline deviation and both maxillary lateral incisors crossbite. Four bimaxillary premolars were extracted. Improved super-elastic Ti-Ni alloy wire (ISW, developed by Tokyo Medical and Dental University) leveling was performed to relieve the crowding and to correct the high canine and midline deviation. Intermaxillary elastics (IME) was applied for a better interdigitation. Treatment was completed within 29 months and a desirable occlusion was achieved.

Mandibular canine distalization plays a key role in orthodontic treatment planning, particularly in cases involving premolar extraction. A three-dimensional symmetric finite element analysis (FEA) model with bilinear periodontal ligament (PDL) properties to evaluate the combined effects of five occlusal conditions—intercuspal position (ICP), incisal clench (INC), right unilateral molar clench (RMOL), right group function (RGF), and no occlusion—and three orthodontic force levels (0.98, 1.47, and 1.96 N) on PDL biomechanics. The effects were assessed by measuring hydrostatic stress as an indicator of capillary perfusion and maximum principal strain as a mechanical signal for tissue deformation and bone remodeling stimulus. According to the FEA results, a moderate force of 1.47 N produced a relatively favorable biomechanical response under nonocclusal conditions. Intercuspal position and incisal clench conditions were associated with elevated stress and strain concentrations in the PDL. The right unilateral molar clench condition preserved load-induced bilateral symmetry, whereas the right group function condition resulted in differential left–right biomechanical responses in the PDL under asymmetric occlusal loading conditions. These findings indicate that occlusal loading is a key mechanical factor influencing the biomechanical environment during orthodontic tooth movement. FEA simulations that consider occlusal loading can provide comparative biomechanical insights that can guide the selection of orthodontic forces and identification of mechanical risks.