OBJECTIVES: The objective of this study is to measuring the morphology and position of bilateral temporomandibular joints in patients with unilateral and bilateral molar scissor bite and simulating the deformation of the mandible during occlusion, in order to provide thesis for the diagnosis of temporomandibular joint disease in patients with unilateral and bilateral molar scissor bite. METHODS: This study was a retrospective study. A total of 10 patients with unilateral molar scissor bite (the unilateral molar scissor bite group) and 10 patients with bilateral molar scissor bite (the bilateral molar scissor bite group) were selected as the experimental group, and 20 adult patients with classⅠ of angle classification of similar ages were selected as the control group. All patients underwent cone beam computed tomography scans, by measuring the width of the fossa, height of the fossa, articular eminence inclination, long axis of the condyle, minor axis of the condyle, horizontal angle of the condyle and the space of the temporomandibular joint, compare temporomandibular joint morphology and position. The three-dimensional finite element analysis of the mandible morphology was carried out to evaluate the force and deformation of the mandible by using software to simulate the occlusion of the patients. It was further explored the relationship between the force of the mandible morphology and the possible temporomandibular joint disorder symptoms of the patients. RESULTS: Intergroup comparisons for the unilateral molar scissor bite group and left sides of the other groups revealed that the superior articular space in the group with unilateral molar scissor bite was shorter than that in the control group (P<0.05); the long axis of the condyle in the unilateral and bilateral molar scissor bite group were both shorter than that of the control group (P<0.05); among which the unilateral group was larger than the bilateral group, and the minor axis of the condyle in bilateral molar scissor bite group was smaller than in the control group (P<0.05), and the unilateral and bilateral condylar groups were larger than the control group (P<0.05); and the condylar horizontal angle in the unilateral and bilateral groups were larger than that in the control group (P<0.05). The normal sides of the unilateral molar scissor bite group and right sides of the other groups had smaller superior articular space than the control group (P<0.05); and the condylar long-axis in bilateral group was smaller than the control group (P<0.05); and the normal side of the condylar short-axis unilateral group was larger than that of the bilateral condylar group. Three-dimensional finite element analysis: the condyle of patients with molar scissor bite was a concentrated area of deformation during the bite of the mandible, when the first molar occlusion of the scissors bite side was simulated, the maximum deformation was located in the condyle in the X-axis and Z-axis directions. The amount of deformation was greater than that of the scissor bite side in the X-axis direction, while in the Z-axis direction, the normal side was greater than the scissor bite side. The maximum sites of local deformation in the X-axis direction were located in anterior and posterior the transverse crest of scissor bite side, and the minimum sites of local deformation was at 1/3 of the anterior slope of the inner pole of the normal side, the maximum local deformation sites in the Z-axis direction were located in the outer pole and below the outer pole of the normal side. The X-axis deformation value was the largest in the molars occlusion on the normal side, the Y-axis deformation value was in the premolars occlusion on the normal side, and the Z-axis deformation value was the largest in the centric occlusion, the deformation value of the condyle was not most significant in molar scissor bite. CONCLUSIONS Unilateral and bilateral molar scissor bite resulting in a short condyle morphology, and the bilateral group had a shorter condylar morphology than the unilateral group. The condyle of the patient with molar scissor bite is a concentrated area of poor occlusal deformation, and the largest sites of deformation are distributed near the transverse ridge of the inner and outer poles of the condyle. Different occlusion conditions have an effect on condylar deformation values, but do not indicate whether there is a clear association between them.
Humans ; Finite Element Analysis ; Retrospective Studies ; Temporomandibular Joint/pathology* ; Cone-Beam Computed Tomography ; Mandible/pathology* ; Imaging, Three-Dimensional ; Adult ; Temporomandibular Joint Disorders/diagnostic imaging* ; Mandibular Condyle/diagnostic imaging* ; Female ; Male ; Molar

OBJECTIVES: This retrospective study aimed to investigate factors influencing positional changes of the condyle and temporomandibular joint (TMJ) following mandibular defect reconstruction with bone flaps, and to evaluate the biomechanical impacts of flap reconstruction on condylar positioning, thereby providing evidence for optimizing surgical protocols and TMJ functional rehabilitation. METHODS: A retrospective study was conducted on 90 patients undergoing mandibular segmental resection with immediate bone flap reconstruction at Guizhou Medical University Affiliated Stomatological Hospital (June 2019 to May 2024). After strict screening, 50 cases with complete data were analyzed. Clinical parameters (defect size, location, reconstruction method) and craniofacial CT scans at four timepoints [preoperative (T0), 7-10 days (T1), 3 months (T2), and 6 months (T3) postoperatively] were collected. Mimics 20 software facilitated 3D reconstruction for measuring TMJ anterior/posterior/superior joint spaces (Kamelchuk method) and calculating condylar position via the Pullinger index [Ln (posterior/anterior space)]. Vitral and Krisjane methods quantified mandibular linear parameters (ramus length, condylar pole distances to the sagittal plane, angulation) and glenoid fossa morphology. Statistical analyses were performed using SPSS 21.0. RESULTS: Mandibular defect size and location were significant factors influencing postoperative condylar position changes (P<0.05). Compared to preoperative measurements, postoperative condylar anterior, posterior, and superior joint spaces were significantly increased (P<0.001). The most pronounced anterior condylar displacement occurred within 7-10 days postoperatively (P<0.05). In patients with condyle resection, postoperative joint space and angle changes were significant; in patients with condyle preservation, only superior and anterior joint space changes were statistically significant (P<0.05). Additionally, from T1 to T2, the changes in condylar medial-lateral distance, superior joint space, and anterior joint space were negatively correlated with the preoperative condylar position. Compared with preoperative,in the T0-T1 period, condylar medial-lateral distance, posterior joint space, and articular tubercle angle changes were significantly negatively correlated with time (P<0.05). Notably, the angle between the condylar long axis and the coronal axis showed a sustained negative trend from T1 to T3 (P<0.05). CONCLUSIONS Condylar position changes after mandibular defect repair with bone flap reconstruction are associated with the size and location of the defect. Additionally, adaptive remodeling of the temporomandibular joint (TMJ) joint space occurs postoperatively. The phenomenon of anterior displacement of the condyle in the early postoperative period (7-10 days) shows a trend of reduction with prolonged follow-up time, and further sample size research is needed.
Humans ; Retrospective Studies ; Temporomandibular Joint/surgery* ; Mandibular Condyle/surgery* ; Male ; Female ; Adult ; Middle Aged ; Mandibular Reconstruction/methods* ; Mandible/surgery* ; Surgical Flaps ; Tomography, X-Ray Computed ; Young Adult ; Biomechanical Phenomena ; Aged ; Adolescent ; Imaging, Three-Dimensional

This study explored a novel digital design and fabrication method for a double constrained split orthodontic miniscrew guide to improve the accuracy and safety of clinical miniscrew implantation and reduce related complications. A patient requiring miniscrew implantation was selected, and data were acquired using cone beam computed tomography (CBCT) and intraoral optical scanning. For the construction of a double constrained split guide including a screw-hole guide and an insertion rod guide, different types of software such as Mimics 24.0, Geomagic wrap 2021, and Materialise magics 21.0 were utilized for 3D reconstruction, model integration, and guide design. The guide was then fabricated via laser metal 3D printing. Model and intraoral try-in results demonstrated that the guide fitted well and was stable. Postoperative CBCT verified that the final miniscrew implantation site was consistent with the preoperative design, and no related complications occurred. This double constrained split orthodontic miniscrew guide provides a precise and safe digital solution for clinical miniscrew implantation.
Humans ; Bone Screws ; Cone-Beam Computed Tomography ; Printing, Three-Dimensional ; Orthodontic Anchorage Procedures/instrumentation* ; Imaging, Three-Dimensional ; Computer-Aided Design

OBJECTIVES: To evaluate the accuracy of a self-developed extraoral scanning system based on four-camera stereophotogrammetric technology in the acquisition of three-dimensional positional information on dental implants and conduct a comparative study involving an intraoral scanning system. METHODS: With the use of an in vitro edentulous jaw model with implants, extraoral (experimental group) and intraoral (control group) scanning systems were employed to obtain STL (Standard Tessellation Language) datasets containing three-dimensional morphological and positional information on scan bodies. In addition, a dental model scanner was used to obtain reference data. The three-dimensional morphological, linear, and angular deviations between groups and reference data were analyzed using Geomagic Wrap 2021 software to compare trueness and precision. RESULTS: The extraoral scanning system demonstrated superior trueness in three-dimensional morphological, linear, and angular deviations compared with the intraoral scanning system, with statistically significant differences (P<0.001). The extraoral scanning system also showed a higher precision in three-dimensional morphological deviation (P<0.001). As the number of implants increased, the extraoral scanning system exhibited increased three-dimensional morphological and linear deviations (P<0.001) but maintained a stable angular deviation. The intraoral scanning system displayed significant increases in three-dimensional morphological, linear, and angular deviations with the increase in the number of implants (P<0.05). CONCLUSIONS The stereophotogrammetry-based extraoral scanning system outperforms intraoral scanning system in terms of the accuracy for multi-unit implant positioning and provides a novel approach for attaining a fully digital workflow for implant rehabilitation in edentulous jaws.
Jaw, Edentulous ; Humans ; Dental Impression Technique ; Dental Implants ; Imaging, Three-Dimensional/methods* ; Photogrammetry/methods* ; Models, Dental

A complete plant body consists of elements on different scales, including microscopic molecules, mesoscopic multicellular structures, and macroscopic tissues and organs, which are interconnected to form complex biological networks. The growth and development of plants involve the regulation of elements on different scales and their biological networks, which requires the coordinated operation of multiple molecules, cells, tissues, and organs. It is difficult to reveal the essence of multi-level life activities by a single method or technology. In recent years, the development of various novel imaging technologies has provided new approaches for revealing the complex life activities in plants. Using multi-modal imaging technologies to study the cross-scale network connections of plants from the microscopic, mesoscopic, and macroscopic levels is crucial for understanding the complex internal connections behind biological functions. This paper first summarizes multi-modal cross-scale imaging technologies, three-dimensional reconstruction, and image processing methods, outlines the basic framework of cross-scale network connection properties, and then summarizes the applications of multi-modal imaging technologies in elucidating plant multi-scale networks. Finally, this review systematically integrates the combined analysis of cross-scale 3D spatial structural data and single-cell omics, laying a theoretical foundation for the innovation of novel plant imaging technologies. Furthermore, it provides a new research paradigm for in-depth exploration of the interaction mechanisms among cross-scale elements and the principles of biological network connectivity in plant life activities.
Plants/metabolism* ; Imaging, Three-Dimensional/methods* ; Image Processing, Computer-Assisted/methods* ; Multimodal Imaging/methods* ; Plant Physiological Phenomena

A nodule in the right middle lobe of the lung was treated by a combination of cone-beam CT,three-dimensional registration for fusion imaging,and electromagnetic navigation bronchoscopy-guided thermal ablation.The procedure lasted for 90 min,with no significant bleeding observed under the bronchoscope.The total radiation dose during the operation was 384 mGy.The patient recovered well postoperatively,with only a small amount of blood in the sputum and no pneumothorax or other complications.A follow-up chest CT on the first day post operation showed that the ablation area completely covered the lesion,and the patient was discharged successfully.
Humans ; Bronchoscopy/methods* ; Catheter Ablation/methods* ; Cone-Beam Computed Tomography ; Electromagnetic Phenomena ; Imaging, Three-Dimensional ; Lung Neoplasms/diagnostic imaging* ; Tomography, X-Ray Computed

Objective To evaluate the application value of four-dimensional CT(4D-CT)in the preoperative localization of primary hyperparathyroidism(PHPT). Methods A retrospective analysis was conducted on the clinical data and parathyroid 4D-CT images of 63 patients who underwent PHPT surgery at Peking Union Medical College Hospital between April 2020 and April 2023.Based on the clinical experience of the hospital's surgeons,parathyroid lesions were categorized into six anatomical regions:around the upper pole of the thyroid,posterior to the mid-thyroid,posterior to the lower pole of the thyroid and the tracheoesophageal groove,below the lower pole of the thyroid and the suprasternal fossa,retrosternal anterior mediastinum,and other rare locations.All images were independently analyzed by two experienced radiologists,with discrepancies resolved through discussion led by a senior radiologist.Using pathological results as the gold standard,the accuracy,sensitivity,specificity,positive predictive value(PPV),negative predictive value(NPV),Youden index,positive likelihood ratio(PLR),and negative likelihood ratio(NLR)of preoperative 4D-CT in diagnosing PHPT were calculated. Results There were no statistically significant differences between preoperative 4D-CT and surgical localization in the following regions:around the upper pole of the thyroid(χ²=0.500,P=0.480),posterior to the mid-thyroid(χ²<0.001,P>0.999),posterior to the lower pole of the thyroid and the tracheoesophageal groove(χ²=0.571,P=0.450),below the lower pole of the thyroid and the suprasternal fossa(χ²<0.001,P>0.999),retrosternal anterior mediastinum(χ²<0.001,P>0.999),and other rare locations(χ²<0.001,P>0.999).The preoperative 4D-CT diagnosis of PHPT lesions demonstrated a sensitivity of 82.09%,specificity of 97.43%,PPV of 87.30%,NPV of 96.19%,accuracy of 94.71%,Youden index of 79.52%,PLR of 31.94,and NLR of 0.18. Conclusion Parathyroid 4D-CT demonstrates good diagnostic efficacy in the preoperative localization of PHPT.
Humans ; Hyperparathyroidism, Primary/surgery* ; Retrospective Studies ; Four-Dimensional Computed Tomography ; Male ; Female ; Middle Aged ; Adult ; Aged ; Parathyroid Glands/diagnostic imaging* ; Preoperative Period

During transfer tasks, the dual-arm nursing-care robot require a human-robot mechanics model to determine the balance region to support the patient safely and stably. Previous studies utilized human-robot two-dimensional static equilibrium models, ignoring the human body volume and muscle torques, which decreased model accuracy and confined the robot ability to adjust the patient's posture in three-dimensional spatial. Therefore, this study proposes a three-dimensional spatial mechanics modeling method based on individualized human musculoskeletal multibody dynamics. Firstly, based on the mechanical features of dual-arm support, this study constructed a foundational three-dimensional human-robot mechanics model including body posture, contact position and body force. With the computed tomography data from subjects, a three-dimensional femur-pelvis-sacrum model was reconstructed, and the individualized musculoskeletal dynamics was analyzed using the ergonomics software, which derived the human joint forces and completed the mechanic model. Then, this study established a dual-arm robot transfer platform to conduct subject transfer experiments, showing that the constructed mechanics model possessed higher accuracy than previous methods. In summary, this study provides a three-dimensional human-robot mechanics model adapting to individual transfers, which has potential application in various scenarios such as nursing-care and rehabilitating robots.
Humans ; Robotics ; Biomechanical Phenomena ; Posture ; Imaging, Three-Dimensional ; Nursing Care

OBJECTIVE: To precise classify sacral meningeal cysts, effective guide minimally invasive neurosurgery and postoperative personalized rehabilitation by multiple dimensions radiographic reconstruction MRI. METHODS: From March to December 2021, based on the original 3D-fast imaging employing steadystate acquisition (FIESTA) scanning sequence, 92 patients with sacral meningeal cysts were pre-operatively evaluated by multiple dimensional reconstruction MRI. The shape of nerve root and the leakage of cyst were reconstructed according to the direction of nerve root or leakage track showed on original MRI scans. Sacral canal cysts were accurately classified as including nerve root and without nerve root, so as to accurately design the incision of skin and formulate corresponding open range of the posterior wall of the sacral canal. Under the microscope intraoperation, the shape of the nerve roots inside cysts or leakage track of the cysts without nerve roots were verified and explored. After the reinforcement and shaping operation, several reexaminations of multiple dimensional reconstruction MRI were performed to understand the deformation of the nerve root and hydrops in the operation cavity, so as to formulate a persona-lized rehabilitation plan for the patients. RESULTS: Among the 92 patients with sacral mengingeal cyst, 58 (63.0%) cysts with nerve root cyst, 29 (31.5%) cysts without nerve root cyst, and 5 (5.4%) cysts with mixed sacral canal cyst. In 58 patients with nerve root cysts, the accuracy of preoperative clinical classification on MRI image reached 96.6% (56/58) through confirmation by operating microscope. Only 2 cases of large single cyst with nerve root on the head of cyst were mistaken for without nerve root type. In 29 patients with sacral cyst without nerve root, the accuracy of preoperative image reached 100% through confirmation by operating microscope. The accuracy of judging the internal nerve root and leakage of 12 cases with recurrent sacral cyst was also 100%. Two cases of delayed postoperative hydrops were found one month after operation. After rehabilitation treatment by moxibustion and bathing, the hydrops disappeared 4-6 months after operation. CONCLUSION Multiple dimensional reconstruction MRI can precisely make clinical classification of sacral meningeal cysts before operation, guide minimally invasive neurosurgery effectively, and improve the rehabilitation effect.
Humans ; Magnetic Resonance Imaging/methods* ; Male ; Female ; Sacrum/surgery* ; Adult ; Middle Aged ; Imaging, Three-Dimensional/methods* ; Cysts/rehabilitation* ; Aged ; Adolescent ; Young Adult ; Spinal Nerve Roots/diagnostic imaging* ; Minimally Invasive Surgical Procedures ; Neurosurgical Procedures/methods*

OBJECTIVE: To compare the registration accuracy of cone beam computed tomography (CBCT) images while registering to virtual craniodentofacial patients based on soft tissue and the dentition registration method. METHODS: Virtual dentofacial patients out of 13 selected participants who needed CBCT scanning were established by impression with a registered-block impression (RBI) based on digital dental images, three-dimensional (3D) facial images and maxillofacial CBCT images. CBCT images were processed in the Mimics software program, establishing the craniofacial virtual patients based on CBCT images (CCTs). Registration between virtual patients from RBI and CCT, using the soft tissue in lower half face (STE) and dentition (DTN) as the reference area, respectively, forming two kinds of virtual craniofacial patients based on digital dental images, 3D facial images and skeletal images of CBCT (hiding the soft tissue and dental casts from CBCT). Three-dimensional deviation analysis was performed in the upper half face and lower half face of facial images from CBCT between two kinds of virtual craniodentofacial patients and compared with 3D facial images from RBI and recorded as root mean square error (RMSE). Paired-t test was used to compare the deviations of RMSEs between the upper and lower half of the face and the upper half of the face of facial images from CCT, respectively, between the two kinds of virtual craniodentofacial patients based on STE and DTN methods. RESULTS: Paired-t tests showed that there was no statistically significant difference between the upper and lower half faces of facial images from CCT between STE and DTN (P>0.05), but the deviation of RMSEs of the upper half face of facial images from CCT in STE was smaller than those in DTN [(1.696±0.420) mm vs. (1.752±0.424) mm, P < 0.01]. CONCLUSION The registration accuracy of CBCT registered in virtual craniodentofacial patients using soft tissue as the reference area was higher.
Humans ; Cone-Beam Computed Tomography/methods* ; Imaging, Three-Dimensional/methods* ; Male ; Face/anatomy & histology* ; Female ; Adult ; Image Processing, Computer-Assisted/methods* ; Young Adult ; User-Computer Interface