Alveolar bone reconstruction simulation is an effective means for quantifying orthodontics, but currently, it is not possible to directly obtain human alveolar bone material models for simulation. This study introduces a prediction method for the equivalent shear modulus of three-dimensional random porous materials, integrating the first-order Ogden hyperelastic model to construct a computed tomography (CT) based porous hyperelastic Ogden model (CT-PHO) for human alveolar bone. Model parameters are derived by combining results from micro-CT, nanoindentation experiments, and uniaxial compression tests. Compared to previous predictive models, the CT-PHO model shows a lower root mean square error (RMSE) under all bone density conditions. Simulation results using the CT-PHO model parameters in uniaxial compression experiments demonstrate more accurate prediction of the mechanical behavior of alveolar bone under compression. Further prediction and validation with different individual human alveolar bone samples yield accurate results, confirming the generality of the CT-PHO model. The study suggests that the CT-PHO model proposed in this paper can estimate the material properties of human alveolar bone and may eventually be used for bone reconstruction simulations to guide clinical treatment.
Humans ; Tomography, X-Ray Computed/methods* ; Porosity ; Alveolar Process/physiology* ; Bone Density ; Computer Simulation ; Elasticity ; X-Ray Microtomography ; Stress, Mechanical ; Finite Element Analysis ; Models, Biological

OBJECTIVE: To explore effectiveness of TiRobot-assisted screw implantation in the treatment of coracoid process fractures of the scapula. METHODS: A retrospective analysis was conducted on the clinical data from 24 patients with coracoid process fractures of the scapula admitted between September 2019 and January 2024 and met selection criteria. Among them, 12 patients underwent TiRobot-assisted screw implantation (robot group) and 12 underwent manual screw implantation (control group) during internal fixation. There was no significant difference ( P>0.05) in baseline data such as gender, age, body mass index, disease duration, cause of injury, coracoid process fracture classification, and proportion of patients with associated injuries between the two groups. The incision length, operation time, intraoperative blood loss, hospital stay, accuracy of screw placement, coracoid process fracture healing time, and complications were recorded and compared, as well as pain visual analogue scale (VAS) score, and Constant-Murley score at last follow-up. RESULTS: The intraoperative blood loss and incision length in the robot group were significantly lower than those in the control group ( P<0.05); however, there was no significant difference in operation time and hospital stay between the two groups ( P>0.05). All patients were followed up 8-27 months (mean, 17.5 months), and the difference in follow-up time between the two groups was not significant ( P>0.05). At last follow-up, the VAS score for shoulder pain in the robot group was signifncatly lower compared to the control group, and the Constant-Murley score was significantly higher ( P<0.05). In the robot group, 16 screws were implanted intraoperatively, while 13 screws were implanted in the control group. Radiographic re-evaluation showed that the excellent and good rate of screw implantation was higher in the robot group (93.8%, 15/16) than in the control group (61.5%, 8/13), but the difference in the precision of screw implantation between the two groups was not significant ( P>0.05). Four patients in the robot group and 1 in the control group achieved double screws fixation; however, the difference in achieving double screws fixation between the two groups was not significant ( P>0.05). All fractures healed in both groups with 1 case of malunion in the control group. There was no significant difference in healing time between the two groups ( P>0.05). During follow-up, 1 patient in the control group experienced screw loosening and displacement. There was no significant difference in the incidence of screw loosening and fracture malunion between the two groups ( P>0.05). CONCLUSION Compared with manual screw implantation, TiRobot-assisted minimally invasive treatment of coracoid process fractures of the scapula can reduce intraoperative blood loss, shorten incision length, alleviate pain, and obtain better promote shoulder joint functional recovery.
Humans ; Male ; Female ; Retrospective Studies ; Fracture Fixation, Internal/instrumentation* ; Minimally Invasive Surgical Procedures/instrumentation* ; Adult ; Middle Aged ; Fractures, Bone/surgery* ; Bone Screws ; Coracoid Process/surgery* ; Robotic Surgical Procedures/methods* ; Scapula/surgery* ; Treatment Outcome ; Operative Time ; Young Adult ; Length of Stay ; Blood Loss, Surgical

OBJECTIVE: To investigate the possible mechanism and fracture stability of subtypes of type B Hangman's fracture by using imaging observation. METHODS: Patients with type B Hangman's fractures admitted to multiple centers between January 2008 and October 2023 were selected as the research objects. The clinical data and imaging data of patients who met the selection criteria were extracted. The patients' age, gender, cause of fracture, disease duration, visual analogue scale (VAS) score of neck pain, neck disability index (NDI), and American Spinal Injury Association (ASIA) classification of spinal cord function were collected. Based on the imaging data, the anatomical structure of the contralateral superior articular process fracture, the relationship between the superior articular process fracture line and the position of the odontoid process, the associated posterior vertebral wall fracture and its classification, the incidence of vertebral arch floating and C _{2, 3} instability were observed. The superior articular fracture angle (SAFA), superior articular fracture displacement distance (SAFD), and C ₂ vertebral body rotation (VBRA) were measured. According to the anatomical structure of the contralateral superior articular process fracture, the patients were divided into a pedicle fracture group (POA group), a inferior articular process fracture group (IAP group), and a laminar fracture group (CSL group). The baseline data and imaging indexes were analyzed between groups, and the imaging anatomical characteristics of each subtype of fracture were observed to explore its possible mechanism and fracture stability. RESULTS: A total of 86 cases of type B Hangman's fractures were collected. There were 67 males and 19 females. The mean age was 51.0 years (range, 21-78 years). There were 48 cases of pedicle fracture (POA group), 25 cases of inferior articular process fracture (IAP group), and 13 cases of laminar fracture (CSL group). There was no significant difference in age, gender, cause of fracture, disease duration, VAS score of neck pain, and NDI between groups ( P>0.05). However, the incidence of spinal cord injury in POA group was the highest ( P<0.05). The incidences of superior articular process fracture line posterior to the odontoid process and posterior vertebral wall fracture in POA group were the highest ( P<0.05). The incidences of vertebral arch floating and C _{2, 3} instability in IAP group were the highest ( P<0.05). There were significant differences in SAFA and VBRA between groups ( P<0.05). There was no significant difference in SAFD between groups ( P>0.05). The differences in the incidences of fracture displacement>3 mm and VBRA>5° between groups were significant ( P<0.05). There were 78 cases of unstable Hangman's fracture, including 2 cases of simple C _2、3 instability, 22 cases of simple axis rotation and displacement instability, 8 cases of simple vertebral arch floating instability, and the rest of the patients had two or more types of instability. CONCLUSION The mechanism of different subtypes of type B Hangman's fracture may be that the lateral mass of the rotation of the atlas applied the overextension compression force to the unilateral superior articular process of the axis vertebra, and the contralateral pedicle, inferior articular process and lamina fractures were caused by direct violence or/and rotational violence to different degrees. The decomposition of this type of fracture into C _{2, 3} intervertebral, axis vertebra body displacement and rotation and vertebral arch floating instability is beneficial to the treatment and surgical approach selection.
Humans ; Spinal Fractures/surgery* ; Male ; Female ; Cervical Vertebrae/diagnostic imaging* ; Middle Aged ; Adult ; Tomography, X-Ray Computed ; Aged ; Odontoid Process/injuries* ; Fracture Fixation, Internal/methods* ; Young Adult

OBJECTIVE: To compare the effectiveness of using a composite loop plate to reconstruct the coracoclavicular ligament around the coracoid process and using a clavicular hook plate for fixation in treatment of Rockwood type Ⅲ acute acromioclavicular joint dislocation. METHODS: A retrospective analysis was conducted on the clinical data of 60 patients with Rockwood type Ⅲ acute acromioclavicular joint dislocation who were admitted between June 2022 and September 2023 and met the selection criteria. Among them, 30 patients were treated with the composite loop plate to reconstruct the coracoclavicular ligament around the coracoid process (loop plate group) and 30 with clavicular hook plate fixation (hook plate group). There was no significant difference in baseline data between the two groups ( P>0.05), including gender, age, injured side, cause of injury, disease duration, preoperative visual analogue scale (VAS) score for pain, and Constant-Murley score. The incision length, operation time, length of hospital stay, and the occurrence of complications during follow-up were recorded. The Constant-Murley score and VAS score were used to evaluate shoulder joint function and pain, and the differences (change values) of the indicators between before operation and at 6 months after operation were calculated for inter-group comparison. In the loop plate group, the coracoclavicular distance (CCD) on the anteroposterior X-ray films of the acromioclavicular joint was measured at 1 day and 6 months after operation to assess the loss of acromioclavicular joint reduction. RESULTS: The incision length of the loop plate group was significantly shorter than that of the hook plate group ( P<0.05). There was no significant difference in the operation time and the length of hospital stay between the two groups ( P>0.05). All incisions healed by first intention after operation. All patients were followed up 12-18 months (mean, 16.3 months). There was no significant difference in the follow-up time between groups ( P>0.05). The Constant-Murley scores and VAS scores of both groups significantly improved at 6 months after operation when compared with those before operation ( P<0.05); the differences in the change values of the two indicators between groups were significant ( P<0.05). The CCD of the loop plate group were (10.40±0.83) mm at 1 day and (10.70±0.68) mm at 6 months and no repositioning loss was observed. Three cases in the hook plate group had residual shoulder joint pain after operation. The difference in the accidence of complications between groups was not significant ( P>0.05). CONCLUSION For Rockwood type Ⅲ acute acromioclavicular joint dislocation, compared with the clavicular hook plate fixation, the composite loop plate for reconstructing the coracoclavicular ligament around the coracoid process has the advantages of simple operation, safety, minimally invasive, good functional recovery, and fewer complications. Moreover, it avoids the need for a second surgery to remove the internal fixation device, and the patient acceptance and satisfaction are higher.
Humans ; Acromioclavicular Joint/surgery* ; Bone Plates ; Male ; Retrospective Studies ; Female ; Adult ; Ligaments, Articular/injuries* ; Joint Dislocations/surgery* ; Coracoid Process/injuries* ; Treatment Outcome ; Middle Aged ; Plastic Surgery Procedures/instrumentation* ; Fracture Fixation, Internal/instrumentation* ; Young Adult ; Clavicle/surgery*

OBJECTIVE: To investigate the clinical efficacy and safety of ultrasound-guided closed reduction and internal fixation using Kirschner wire for the treatment of olecranon fractures of the ulna in children. METHODS: Between January 2019 and January 2021, 13 children with olecranon fracture were treated with ultrasound-guided closed reduction and percutaneous Kirschner wire internal fixation, including 10 males and 3 females. The age ranged from 3 to 14 years old. Children with ulnar olecranon fractures were evaluated using the Gicquel scoring system. The clinical evaluation encompassed postoperative pain, functional status, and range of motion, with a maximum score of 15 points. The radiological assessment contributed an additional 4 points. A cumulative score of more than 18 scores was classified as excellent, more than 17 scores as good, more than16 scores as fair, and less than 16 scores as poor. Clinical assessment:A score of 14 indicates excellent performance, a score of 13 reflects good performance, a score of 12 denotes fair performance, and a score of less than 11 signifies poor performance. RESULTS: A total of 13 patients were followed up, with a duration ranging from 6 to 12 months. According to the Gicquel scoring criteria, the comprehensive evaluation of clinical and radiographic findings yielded 10 excellent and 3 good outcomes. Evaluation based solely on clinical findings resulted in 13 excellent outcomes. CONCLUSION Ultrasound-guided percutaneous cross Kirschner wire fixation for children's olecranon fracture has the advantages of less trauma, rapid recovery, less fluoroscopy, and good recovery of elbow function. The clinical effect is satisfactory.
Humans ; Child ; Male ; Female ; Fracture Fixation, Internal/instrumentation* ; Ulna Fractures/physiopathology* ; Bone Wires ; Child, Preschool ; Adolescent ; Olecranon Process/surgery* ; Ultrasonography ; Closed Fracture Reduction/methods* ; Olecranon Fracture

OBJECTIVE: To evaluate the clinical and radiographic efficacy of micro crestal flap-alveolar ridge preservation following extraction of mandibular molars with severe periodontitis compared with natural healing, and to preliminarily propose the surgical indication. METHODS: A retrospective analysis was conducted on clinical data from patients with mandibular molars with severe periodontitis either receiving micro crestal flap-alveolar ridge preservation (MCF-ARP group) or undergoing natural healing in department of periodontology, Peking University School and Hospital of Stomatology from September 2013 to June 2021. Cone-beam computed tomography scannings performed before/immediately after extraction (as baseline) and repeated before implantation (after the extraction socket healing) were used to measure the ridge width, height and volumetric changes of the sockets, and the proportion of guided bone regeneration (GBR) during implant therapy were compared between the two groups. RESULTS: Between baseline and healing, significant differences in changes of MCF-ARP group [(8.34±2.81) mm] and natural healing group [(3.82±3.58) mm] in the distances from mandibular canal to center of the tooth socket were recorded (P < 0.001). The ridge width at 1 mm below the most coronal aspect of the crest increased by (3.50±4.88) mm in the MCF-ARP group but decreased by (0.16±5.70) mm in the natural healing group, respectively (P=0.019). After healing, the MCF-ARP group showed the distances from mandibular canal to center of the tooth socket >8 mm in all the cases, with 97.1% exceeding 10 mm. Natural healing group displayed 23.1% of the cases with center bone height < 8 mm and 61.5% exceeding 10 mm. Volume changes at the buccal and lingual aspect as well as the total socket were significantly greater in the MCF-ARP group compared with natural healing group (P < 0.001).At the time of implantation, GBR was performed in 5 out of 68 subjects (8.3%) in the MCF-ARP group, whereas 8 out of 26 subjects (30.8%) in the natural healing group required GBR, reflecting significant difference (P=0.003). CONCLUSION In the sites of mandibular molars with severe periodontitis, when the distances from mandibular canal to center of the tooth socket was not enough (less than 7 mm), clinicians could consider performing the micro crestal flap-alveolar ridge preservation to achieve augmentation for alveolar ridge and reduce the proportion of guided bone regeneration during implant therapy to reduce the difficulty and risk of injuries during implant therapy.
Humans ; Tooth Extraction ; Retrospective Studies ; Surgical Flaps ; Molar/surgery* ; Mandible/surgery* ; Female ; Periodontitis/surgery* ; Male ; Adult ; Middle Aged ; Cone-Beam Computed Tomography ; Alveolar Ridge Augmentation/methods* ; Alveolar Process/surgery* ; Tooth Socket/diagnostic imaging* ; Dental Implantation, Endosseous/methods*

Insufficient alveolar bone thickness increases the risk of periodontal dehiscence and fenestration, especially in orthodontic tooth movement. Abaloparatide (ABL), a synthetic analog of human PTHrP (1-34) and a clinical medication for treating osteoporosis, has recently demonstrated its potential in enhancing craniofacial bone formation. Herein, we show that intraoral submucosal injection of ABL, when combined with mechanical force, promotes in situ alveolar bone thickening. The newly formed bone is primarily located outside the original compact bone, implying its origin from the periosteum. RNA sequencing of the alveolar bone tissue revealed that the focal adhesion (FA) pathway potentially mediates this bioprocess. Local injection of ABL alone enhances cell proliferation, collagen synthesis, and phosphorylation of focal adhesion kinase (FAK) in the alveolar periosteum; when ABL is combined with mechanical force, the FAK expression is upregulated, in line with the accomplishment of the ossification. In vitro, ABL enhances proliferation, migration, and FAK phosphorylation in periosteal stem cells. Furthermore, the pro-osteogenic effects of ABL on alveolar bone are entirely blocked when FAK activity is inhibited by a specific inhibitor. In summary, abaloparatide combined with mechanical force promotes alveolar bone formation via FAK-mediated periosteal osteogenesis. Thus, we have introduced a promising therapeutic approach for drug-induced in situ alveolar bone augmentation, which may prevent or repair the detrimental periodontal dehiscence, holding significant potential in dentistry.
Osteogenesis/drug effects* ; Periosteum/cytology* ; Parathyroid Hormone-Related Protein/administration & dosage* ; Animals ; Focal Adhesion Protein-Tyrosine Kinases/metabolism* ; Alveolar Process/drug effects* ; Cell Proliferation/drug effects* ; Phosphorylation ; Rats ; Male ; Humans ; Focal Adhesion Kinase 1/metabolism* ; Cell Movement/drug effects*

OBJECTIVES: This study explores the differences in fluid flow within alveolar cancellous bone at various sites under orthodontic forces and elucidates the relationship between fluid shear stress and bone remodeling. These fin-dings lay the groundwork for understanding the biomechanical mechanisms of orthodontic tooth movement. METHODS: Stress relaxation tests were performed on human alveolar bone samples to determine material parameters by using the Prony series. An inverse model of alveolar bone was then developed for numerical simulations of fluid-structure interactions to calculate fluid flow within cancellous bone. Meanwhile, a rat model of tooth movement was established to investigate variations in bone remodeling speeds across different regions. RESULTS: The microstructural distribution of cancellous alveolar bone was similar in humans and rats. The bone volume fraction and trabecular thickness gradually decreased from root cervical region to root apical region, while the trabecular space gradually increased. Under the influence of orthodontic forces, fluid shear stress within cancellous bone showed spatial variability across different levels, with the highest shear stress occurring at the root apical region, ranging from 0 to 0.936 6 Pa. Additionally, the rat model of tooth movement indicated that bone remodeling occurred more rapidly at the root apical region. CONCLUSIONS Fluid stimulation has a remarkable effect on al-veolar bone remodeling, causing changes in the structure of alveolar bone and ultimately regulating the speed of structu-ral remodeling.
Bone Remodeling ; Animals ; Tooth Movement Techniques ; Rats ; Alveolar Process/physiology* ; Stress, Mechanical ; Humans ; Biomechanical Phenomena ; Cancellous Bone/physiology* ; Shear Strength

OBJECTIVES: To evaluate the osteogenic efficacy of three-dimensional printing individualized titanium mesh (3D-PITM) as a scaffold material in guided bone regeneration (GBR). METHODS: 1) Patients undergoing GBR for alveolar bone defects were enrolled as study subjects, and postoperative healing complications were recorded. 2) Postoperative cone beam computed tomography (CBCT) scans acquired at least 6 months post-surgery were used to calculate the percentage of actual bone formation volume. 3) Alveolar bone specimens were collected during the first-stage implant surgery for histomorphometric analysis. This analysis quantitatively measured the proportions of newly formed bone and newly formed unmineralized bone within the specimens. Specimens were categorized into three groups based on healing complications (good healing group, wound dehiscence group, 3D-PITM exposure group) to compare differences in the proportions of newly formed bone and newly formed unmineralized bone. RESULTS: 1) Twelve patients were included. Guided bone regeneration failed in one patient, and 3D-PITM exposure occurred in three patients (exposure rate: 25%). 2) The mean percentage of actual bone formation volume in the 11 successful guided bone regeneration cases was 95.23%±28.85%. 3) Histomorphometric analysis revealed that newly formed bone constituted 40.35% of the alveolar bone specimens, with newly formed unmineralized bone accounting for 13.84% of the newly formed bone. Intergroup comparisons showed no statistically significant differences (P>0.05) in the proportions of newly formed bone or newly formed unmineralized bone between the good healing group and the wound dehiscence group or the 3D-PITM exposure group. CONCLUSIONS 3D-PITM enables effective bone augmentation. Radiographic assessment demonstrated favorable bone formation volume, while histological analysis confirmed substantial formation of newly formed mineralized bone within the surgical site.
Humans ; Printing, Three-Dimensional ; Titanium ; Cone-Beam Computed Tomography ; Bone Regeneration ; Osteogenesis ; Surgical Mesh ; Tissue Scaffolds ; Alveolar Process/surgery* ; Adult ; Male ; Middle Aged ; Female ; Wound Healing ; Guided Tissue Regeneration, Periodontal/methods* ; Alveolar Bone Loss/surgery*

OBJECTIVES: To compare the clinical effects of concentrated growth factor (CGF) membrane and Bio-Gide ^® collagen membrane, combined with Bio-Oss ^® sticky bone respectively in alveolar ridge preservation (ARP) of maxillary anterior teeth. METHODS: Thirty patients who needed alveolar ridge preservation after maxillary anterior tooth extraction were selected and randomly assigned to the Bio-Gide group and the CGF group. In both groups, the extraction sockets were tightly filled with the Bio-Oss^® sticky bone. In the Bio-Gide group used Bio-Gide^® collagen membrane to cover the upper edge of the Bio-Oss^® sticky bone and closed the wound. The CGF group, the CGF membrane was covered on the upper edge of the Bio-Oss^® sticky bone and the wound was closed. The soft tissue wound healing status at 10 days after ARP, the changes in alveolar ridge height and width immediately after ARP and at 6 months after ARP, and the doctor-patient satisfaction at 6 months after ARP were compared and evaluated between the two groups. RESULTS: At 6 months after ARP, there was no statistically significant difference in the changes of alveolar bone width and height between the two groups (P>0.05). However, the CGF group showed better performance in soft tissue healing after ARP and doctor-patient satisfaction, and the differences were statistically significant (P<0.05). CONCLUSIONS Compared with the Bio-Gide^® collagen membrane, the combined application of CGF membrane and Bio-Oss^® sticky bone can lead to better soft tissue healing after ARP of maxillary anterior teeth and higher doctor-patient satisfaction, showing obvious advantages in ARP of maxillary anterior teeth.
Humans ; Maxilla/surgery* ; Tooth Extraction ; Alveolar Process/surgery* ; Membranes, Artificial ; Alveolar Ridge Augmentation/methods* ; Intercellular Signaling Peptides and Proteins/therapeutic use* ; Minerals/therapeutic use* ; Collagen ; Wound Healing ; Tooth Socket/surgery* ; Bone Substitutes/therapeutic use* ; Male ; Female ; Middle Aged ; Alveolar Bone Loss/prevention & control* ; Adult