Dentofacial deformities accompanied by dental defects significantly impair the fundamental physiological functions of affected individuals，including chewing，articulation，and respiration.Additionally，these conditions detrimentally affect facial aesthetics，leading to diminished self-esteem and profound implications for psychological well-being and overall quality of life.The primary etiological factors contributing to dentofacial malformations associated with dental defects include congenital tooth agenesis， severe maxillofacial trauma，periodontitis， and dental caries.Given that dentofacial anomalies involve intricate anatomical structures such as the jaws，teeth，soft tissues，and nervous system，the existence of dental defects further complicates the clinical scenario.Conventional treatment strategies，which are often limited to single-specialty or simplistic combined orthodontic-orthognathic approaches，frequently fail to adequately restore the functional and aesthetic aspects of the affected patients.The diagnosis and management of dentofacial anomalies with dental defects typically necessitate a comprehensive and systematic multidisciplinary approach，incorporating expertise from oral and maxillofacial surgery， prosthodontics， orthodontics，implantology，periodontics，endodontics，and other relevant disciplines.By leveraging multidisciplinary collaboration，treatment duration can be significantly reduced， while enhancing the aesthetic outcomes and masticatory function of patients in a timely manner，thus achieving optimal treatment results.

Distraction osteogenesis （DO） was accidentally discovered by the Soviet orthopedic surgeon，Ilizarov，during World War Ⅱ.In the decades following its discovery，DO was not effectively applied in maxillofacial surgery until 1992，when Dr.McCarthy from the United States firstly used DO to treat hemifacial microsomia，setting a precedent for the application of DO in maxillofacial surgery.Since then，DO has been further developed and widely applied in the field of maxillofacial surgery.DO is an autologous bone augmentation technique that is mainly used in maxillofacial surgery to treat jaw defects and insufficient jaw development.It can be seen from the history of its development that DO was not originally part of orthognathic surgery.However，due to its close relationship with dentofacial deformities，orthognathic surgeons were the first to learn and master DO.As a complement to conventional orthognathic surgery， DO has become an important tool for orthognathic surgeons，such that its teaching is also mostly undertaken by orthognathic surgeons.Based on the authors' clinical experience and cases，and in combination with the latest domestic and international literature，this article focuses on the application of DO in the treatment of dentofacial deformities.

Objective

Exploring the effect of class Ⅲlever biomechanical principles on the construction of a condylar resorption model in young rabbits.

Methods

A total of sixteen 6-month-old female rabbits were randomizedly divided into four groups，i.e.，2-week experimental group，4-week experimental group，2-week control group，and 4-week control group，with 4 rabbits in each group.The experimental groups were treated with condylar resorption modeling，and the control groups were left untreated.The condylar resorption modeling method was as follows.The mandibular anterior teeth of rabbits were stacked with high-strength resin protrusions，which prevented the normal occlusion of the maxillary and mandibular teeth during mastication，so that the rabbits could passively perform mandibular backward movements to chew and grind food，and condylar resorption of bilateral temporomandibular joints occurred under the long-term pressure of the classⅢlever biological force.The 2-week experimental group and the 2-week control group were necropsied after 2 weeks of modeling，whereas the 4-week experimental group and the 4-week control group were necropsied after 4 weeks of modeling.Bone metabolism was measured by CT scanning and 3D reconstruction of the temporomandibular joints of rabbits.Specifically，condylar surface area and volume changes，hematoxylin-eosin staining of condylar tissues，and Elisa assay of peripheral blood were evaluated.Independent samples t-test was used for statistical analysis of the data with software（SPSS 19.0）.

Results

（1）CT 3D reconstruction：The volume of the condyle［（196±8）mm³］and the surface area［（280±12）mm²］in the 2-week experimental group significantly decreased compared to those of the control group［（204±9）mm³，（292±13）mm²；t_volume=4.409，P_volume=0.022；t_surfacearea=3.660，P_surfacearea=0.035］.The volume of the condyle［（192±18）mm³］and the surface area［（280± 10）mm²］in the 4-week experimental group significantly decreased compared to those of the control group［（211±11）mm³，（309±10）mm²；t_volume=4.081，P_volume=0.027；t_surfacearea=3.738，P_surfacearea = 0.033］.There was no significant difference in the degree of change in the surface area and volume of the right and left lateral condyles during the same modeling cycle.（2）Hematoxylin-eosin stain：In the 2-week experimental group，increase in the number of cells was observed in the proliferative layer of the condyle，with clustered aggregation of cells and the appearance of homogeneous cell-free areas.In the 4-week experimental group，there was no obvious stratification of the condylar cartilage，and the hypertrophic layer of cells and nuclei were markedly enlarged，with the interstitial space of the trabeculae filled with a large number of erythrocytes.（3）Articular disc in the naked-eye view：The degree of light transmission increased in the middle band of the articular disc in the 2-week experimental group and the 4-week experimental group compared to the control group.（4）Bone metabolism index：Serum osteocalcin concentration：The 2-week experimental group［（35.8±1.4）ng/mL］was higher than the 2-week control group［（18.1±8.1）ng/mL］，and the difference was statistically significant（t=7.814，P=0.004）；The 4-week experimental group［（37.6±1.7）ng/mL］also showed an increase compared with the 4-week control group［（19.3±6.4）ng/mL］，and the difference was statistically significant（t=4.752，P=0.018）.The 25 hydroxyvitamin D concentration：The 2-week experimental group［（126.5±16.8）nmol/mL］decreased compared with the 2-week control group［（176.0±8.9）nmol/mL］，and the difference was statistically significant（t=5.937，P=0.010）.There was no significant difference between the 4-week experimental group and the 4-week control group.Compared with the 2-week experimental group，the 4-week experimental group showed an increase in the concentration of 25 hydroxyvitamin D，while the serum osteocalcin concentration did not change significantly.

Conclusions

The young rabbit condylar resorption model established in this study could better simulate the histopathological changes of condylar resorption disease under mechanical effects and had the advantages of stable and reproducible results，which could provide references for the later experimental and clinical studies.

Objective

The purpose of this study was to analyze the association between the Kihon checklist（KCL）score and the risk factors of oral frailty among elderly individuals in Hanzhong community，and to construct a nomogram model to study the accuracy of oral frailty risk assessment for elderly individuals in Hanzhong community.

Methods

A cross-sectional survey was conducted among 385 elderly individuals in three communities of Hanzhong City from May to July 2024，with 179 eligible elderly individuals finally included.The study used convenience sampling and collected data through questionnaires，including general information，KCL scores，and related lifestyle and health status information.Multivariate logistic regression analysis was used to determine the influencing factors of oral frailty，and a nomogram model was constructed based on these factors.The "rms" package in R software was used for model construction and visualization.The performance of the model was evaluated using the receiver operating characteristic（ROC）curve，and the accuracy of the model was verified using a calibration curve.

Results

The study found that age，living alone，nutritional status，and diabetes were independent influencing factors of oral frailty（P＜0.05）.The constructed nomogram model showed good performance in the ROC curve analysis，with an AUC of 0.757，indicating that the model was useful to assess the risk of oral frailty of the elderly in Hanzhong community.The calibration curve showed that the model's assessment of risk was in good agreement with the actual observed results.

Conclusions

The nomogram model constructed in this study，based on the KCL score，provided an effective tool for assessing the risk of oral frailty among the elderly individuals in Hanzhong community.The model intuitively demonstrated the impact of different factor combinations on the risk of oral frailty among the elderly individuals in Hanzhong community，helping healthcare providers to allocate resources more effectively and intervene on these risk factors.

Objective

The factors influencing the success rate of mature permanent tooth autotransplantation combined with external apical surgery were analyzed to provide reference for clinical judgment of success rate.

Methods

Patients who received autologous tooth transplantation of mature permanent teeth and combined external apical surgery in the Department of Oral Surgery of Stomatology，Hospital of the Fourth Military Medical University from June 2014 to May 2023 were included.The reasons for the external apical surgery were as follows.Firstly，the root apex of the donor tooth was broken passively during extraction.Secondly，the root apex of the donor tooth was too crooked to implant into the recipient area.The possible factors affecting the success rate were summarized and evaluated.Surgical records and photography data from patients' previous medical records，including 12 factors such as gender，age，root shape and donor location，were analyzed.Survival analysis was used for statistical analysis to screen out the factors affecting the cumulative success rate of transplanted teeth after external apical surgery.

Results

The cumulative five-year success rate of 84 transplanted teeth was 77.2%.Single factor Log-Rank analysis showed that the location of the receiving area（P=0.004），the alveolar bone height of the receiving area（P=0.002），the donor time（P=0.005）and the initial stability（P=0.001）were significantly correlated with the cumulative success rate of tooth transplantation after external apical surgery.Multivariate Cox proportional hazard regression analysis showed that the location of the receiving area（P=0.039）and the height of the alveolar bone in the receiving area（P=0.036）were significantly correlated with the success rate of transplantation after external apical surgery.

Conclusions

By reducing the intraoperative time，restoring the alveolar bone height，and ensuring good initial stability，high success rate can be achieved for mature permanent tooth autotransplantation after external apical surgery.

Objective

To investigate the three - dimensional morphological changes of the temporomandibular joint（TMJ）condyle in adult females with high-angle skeletal maxillary protrusion before and after orthodontic treatment using cone-beam computed tomography（CBCT），and to assess the structural adaptation of TMJ induced by orthodontic treatment.

Methods

This controlled study enrolled 27 classⅠand 28 classⅡhigh-angle skeletal maxillary protrusion patients treated between January 2018 and December 2023 in the Sixth Affiliated Hospital of South China University of Technology and the Second People's Hospital of Foshan.Pre- and post-treatment CBCT scans were analyzed for joint spaces，condylar/articular fossa morphology（height/volume/surface area），and skeletal parameters（MP-SN angle，S-Go/N-Me ratio，Y-axis angle）.Paired and independent t-tests were applied for within-and between-group comparisons（α=0.05）.

Results

In classⅠhigh-angle patients，no significant post-treatment changes were observed in TMJ parameters：Superior joint space［（3.19±0.62）mm vs.（3.02±0.67）mm，t=0.998，P=0.328］，anterior joint space［（2.44±0.32）mm vs.（2.52±0.48）mm，t=-0.859，P=0.398］，posterior joint space［（2.48±0.34）mm vs.（2.43±0.28）mm，t=0.603，P=0.552］，condylar apex height［（6.54±0.74）mm vs.（6.69±0.74）mm，t=-0.801，P=0.431］，condylar apex volume［（452.91±35.90）mm³ vs.（472.18±57.97）mm³，t=-1.407，P=0.171］，condylar height［（18.18±2.44）mm vs.（18.92±4.30）mm，t=-0.819，P=0.420］，and condylar volume［（1 690.07±214.94）mm³ vs.（1 754.38±348.92）mm³，t=-0.869，P=0.393）］.Articular fossa morphology and skeletal parameters also remained stable.In classⅡhigh-angle patients，significant post-treatment reductions were observed：Condylar height［（16.28±2.57）mm vs.（14.00±2.56）mm，t=3.168，P=0.004］，condylar volume［（1 512.46±223.50）mm³ vs.（1 360.96±230.94）mm³，t=2.377，P=0.025］，MP-SN angle［（40.99±3.97）° vs.（36.96±4.05）°，t=3.580，P = 0.001］，Y-axis angle［（69.72 ± 3.38）° vs.（62.82 ± 3.36）°，t = 7.145，P＜0.001］，with concurrent adjustments in joint spaces［posterior：（2.23±0.40）mm vs.（2.50±0.36）mm，t=-2.476，P=0.020；anterior：（2.83±0.36）mm vs.（2.55±0.34）mm，t=2.843，P=0.008］.Intergroup comparisons revealed greater post-treatment changes in classⅡfor condylar height（P=0.011），condylar volume（P=0.031），and Y-axis angle（P＜0.001）.

Conclusions

Orthodontic vertical control effectively improved occlusion in high-angle malocclusion patients.In class Ⅰcases，TMJ structures remained stable after treatment，with no significant changes in joint space，condylar morphology，and articular fossa.In contrast，class Ⅱ patients exhibited biomechanical adaptation through anterior - inferior condylar repositioning，accompanied by significant reductions in condylar volume and Y-axis angle.These findings underscored the necessity of individualized treatment strategies to harmonize occlusal function with condylar remodeling，particularly in classⅡhigh-angle maxillary protrusion cases.

Objective

To compare the clinical outcomes of immediate and conventional loaded blade-threaded implants placed in premolar sites.

Methods

This study was designed as a prospective randomized clinical trial.A total of 30 patients with premolars missing and treated with 30 blade-threaded implants from March to August in 2023 were divided into immediate or conventional loading group randomizedly.The immediate loading group was restored provisionally within five days after implant placement with an insertion torque more than 50 N·cm，and the conventional loading group was restored three months later.The implant success rate，implant stability quotien，marginal bone loss，peri-implant soft tissue and complications were recorded and evaluated at three different timepoints，i.e.，implant placement，three months later and one year later.Two-sample t-test was used to analyze the inter-group data.

Results

During the one-year follow up period，no patient dropped out and no implant failed.The mean implant stability quotien（ISQ）values were（83.4±1.6）and（82.7±2.1）for immediate and conventional loading group，repectively，and there was no significant difference（t = 1.551，P = 0.143）.The mean marginal bone loss was（0.67±0.39）mm in the immediate loading group，which was slightly higher than that of the conventional loading group（0.42±0.38）mm without statistical difference（t=1.760，P=0.089）.Peri-implant soft tissue and complications were similar except for the proximal contact loss between the two groups.Gigival index of the immediate and conventional group was（0.35 ± 0.32）and（0.33 ± 0.49），respectively，without significant difference（t=1.228，P=0.268）.Plaque index of the two groups was（0.42±0.30）and（0.33±0.35），without significant difference（t=1.463，P=0.154）.Probing depth of the two groups was（2.49±0.64）and（2.43±0.53）mm，without significant difference（t=1.362，P=0.183）.Proximal contact loss was observed in four patients in the conventional loading group.

Conclusions

Within the limitations of this study，the present data seemed to support the hypothesis that the clinical outcomes of the immediate and conventional loaded blade-threaded implants in the premolar sites were comparable.Digital technique and blade-threaded implants could facilitate the immediate loading protocol.

Skeletal class Ⅲmalocclusion，manifested by excessive mandibular growth and/or hypoplasia of the maxilla，is typified by molar mesial occlusion，anterior crossbite，pronounced classⅢskeletal morphology，and mandibular prognathism，either with or without functional crossbite.This condition exerts a profound impact on oral functionality，facial esthetics，and psychological health，posing a significant therapeutic challenge that frequently necessitates orthognathic surgery.This case report presents an adult patient with skeletal class Ⅲmalocclusion who was treated with non-surgical，nonmicroimplant orthodontic camouflage therapy.The etiology is scrutinized，and the diagnostic process，differential diagnoses，and preventive strategies are deliberated to provide clinical practitioners with insights into effective management strategies.

Oxidative stress is a state in which there is an imbalance between oxidative and antioxidant effects in the body.Excessive production of reactive oxygen species（ROS）can damage deoxyribonucleic acid（DNA），proteins，etc，thereby impairing the function of many organs.It is now believed that oxidative stress，as a risk factor，is closely related to the development of a variety of oral diseases，and can cause bone homeostasis dysfunction，inhibit osteoblasts from forming bone and promote osteoclast activity，thus preventing oral bone healing and even exacerbating bone defects，and affecting the normal structure and function of oral cavity.Cerium oxide nanoparticles（CNPs），as a kind of metal oxide-based nanoparticles（NPs），have the ability to scavenge ROS due to the presence of two interchangeable oxidation states，Ce³⁺ and Ce⁴⁺，and the mimetic activity of various antioxidant enzymes.It is currently believed that CNPs have a promotive effect on the treatment of the diseases related to oxidative stress，such as cancer and diabetes mellitus，etc.Therefore，the aim of this article was to provide a review of the anti-oxidative stress effect of CNPs and its impact on the oral osteogenic microenvironment under oxidative stress，with a view to providing references to the research and clinical application of CNPs in the treatment of inflammatory bone defects in the oral cavity.

Cephalometric analysis technology based on two-dimensional images has always been the‘golden standard’.Still，there are the problems of‘anatomical errors’caused by the distortion of two-dimensional images and overlapping of anatomical landmarks，and‘artificial errors’caused by manual punctuation.Three-dimensional（3D）cephalometric analysis，which has been widely used in clinical diagnosis，and playing a more and more important role for resolving the‘anatomical error’problem.Automatic cephalometric analysis，which uses image processing and deep learning for identifying and punctuating cephalometric landmarks automatically，could be used for resolving the‘manual error’problem.Convolutional neural network（CNN）based on deep learning is currently the most effective technology of image processing and target detection，which has shown its great potential for automatic target detection of 3D cephalometric landmarks.Based on literature review，we summarized the current status of 3D cephalometric analysis and the research progress of CNN for automatic target detection of 3D cephalometric landmarks.