Search Results (149)

Background: Central giant cell granuloma of the jaw is a benign but potentially aggressive lesion that can cause pain, facial deformity, tooth loss, and jaw destruction. Many treatment methods are described in the literature, but the less invasive ones are associated with a higher recurrence rate. For several decades, extensive bone resection procedures have been the most effective treatment to date. This study aimed to evaluate a minimally invasive treatment protocol combining multiple weekly intralesional steroid injections with surgical removal of residual tumor tissue and chemical cauterization using Carnoy’s solution. Methods: Thirteen patients with histologically confirmed central giant cell granulomas of the jaws were treated according to the protocol, including weekly triamcinolone injections and, when necessary, fenestration of the cortical bone to access residual lesions. Patients were monitored clinically and radiologically over six years, with reconstruction of bone defects using autogenous grafts and platelet-rich fibrin. Results: The treatment effectively reduced tumor size, restored cortical bone, and allowed preservation of jaw structure. Only one recurrence was observed, and complications were minor and transient. The protocol was equally effective for both aggressive and non-aggressive lesions, regardless of patient age or comorbidities. Conclusions: These findings suggest that combining pharmacological and surgical approaches with chemical cauterization provides a safe, effective, and tissue-preserving strategy for managing central giant cell granulomas, minimizing recurrence while reducing surgical morbidity. Full article

Background: Autologous tooth-derived grafts have recently gained attention as an innovative alternative to conventional biomaterials for alveolar ridge preservation (ARP) and augmentation (ARA). Their structural similarity to bone and osteoinductive potential support clinical use. Methods: This systematic review was conducted according to PRISMA 2020 guidelines and registered in PROSPERO (CRD420251108128). A comprehensive search was performed in PubMed, Scopus, and Web of Science (2010–2025). Randomized controlled trials (RCTs), split-mouth, and prospective clinical studies evaluating autologous dentin-derived grafts were included. Two reviewers independently extracted data and assessed risk of bias using Cochrane RoB 2.0 (for RCTs) and ROBINS-I (for non-randomized studies). Results: Nine studies involving 321 patients were included. Autologous dentin grafts effectively preserved ridge dimensions, with horizontal and vertical bone loss significantly reduced compared to controls. Histomorphometric analyses reported 42–56% new bone formation within 4–6 months, with minimal residual graft particles and favorable vascularization. Implant survival ranged from 96–100%, with stable marginal bone levels and no major complications. Conclusions: Autologous tooth-derived biomaterials represent a safe, biologically active, and cost-effective option for alveolar bone regeneration, showing comparable or superior results to xenografts and autologous bone. Further standardized, long-term RCTs are warranted to confirm their role in clinical practice. Full article

Aim: This retrospective observational clinical cohort study evaluated 84-month clinical and radiographic outcomes of a regenerative protocol combining autologous dentin grafts processed with the Tooth Transformer^® device and Concentrated Growth Factors (CGFs) in patients with severe maxillary atrophy undergoing sinus augmentation with simultaneous implant placement. Materials and Methods: Thirty-one patients (30–75 years) with residual crestal bone height ≥ 5 mm and requiring extraction of ≥2 molars were included. Extracted teeth were processed with the Tooth Transformer^® to obtain demineralized dentin granules (500–1000 µm), which were combined with CGFs prepared using the Medifuge MF200^® to form “sticky bone.” All patients underwent sinus lift via a lateral window approach (Hilt Tatum technique) with simultaneous placement of 98 implants (12–14 mm), which were loaded after six months. Results: At the 84-month follow-up, no implant failures or peri-implantitis were recorded. CBCT and clinical evaluations showed stable regenerated bone volume and absence of peri-implant bone resorption. All patients received fixed prostheses within six months without complications. Conclusions: The combined use of processed autologous dentin and CGFs proved to be a safe, predictable, and effective regenerative technique in cases of severe maxillary atrophy, with a 100% implant survival rate at five years. Full article

Aiming at the problems of excessive soil disturbance caused by deep plowing and stripped straw backfilling in strip tillage machinery, which are induced by the large amount of residual straw before maize sowing in the Huang-Huai-Hai Region, an integrated tillage machine suitable for pre-sowing strip tillage of summer maize—integrating subsoiling, stubble-crushing, and soil-guiding functions—was designed. First, the physical properties of straw were analyzed to determine the tooth profile parameters of the stubble-crushing wheel. The unique convex structure of the tooth disc enables it to simultaneously perform depth-limiting and soil-pressing functions. By calculating the flow characteristics of soil during tillage, the angle and distance between the subsoiling shovel and the stubble-crushing wheel were designed. This not only enhances soil crushing and flow but also reduces the occurrence of blockages. A discrete element simulation test with quadratic orthogonal rotation combination was conducted. The machine’s forward speed, wheel position distance, and wheel deflection angle were selected as test factors to analyze their effects on the soil loss rate of the seedbed strip and straw backflow effect under different combinations. The optimal combination of parameters was determined as follows: forward speed of 7.383 km/h, front–rear position distance parameter of −10.131 cm, and deflection angle of 8.608°, with the soil loss rate of the seedling belt reaching 5.486% under this condition. Field experiments were conducted in combination with the strip tiller to verify the simulation-optimized parameters, and comparative experiments at different speeds were also carried out. The field experimental results showed that the deviation of the actual soil disturbance rate caused by the machine from the simulated value was −1.166%, and the soil disturbance rate within the seedling belt was even lower. The results indicated that after the operation of the improved machine, there were no obvious ruts on the soil surface, and the straw was evenly distributed at the edge of the seedling belt, which meets the agronomic requirements for maize planting. Full article

The 7075-T7451 aluminum alloy, widely used in aerospace, aviation, and automotive fields for critical load-bearing components due to its excellent mechanical properties, suffers from residual stresses induced by thermo-mechanical coupling during milling, which deteriorate workpiece performance. This study explores how key milling parameters—spindle speed *n_c*, feed per tooth *f_z*, cutting depth *a_p*, and cutting width *a_e*—affect surface residual stress and cutting force via orthogonal experiments and finite element analysis (FEA). Results show *a_e* is critical for X-direction residual stresses, while *f_z* dominates Y-direction ones. Cutting force increases with *f_z*, *a_p*, and *a_e* but decreases with higher *n_c*. Multivariate regression-based prediction models for residual stress and cutting force were established, which effectively characterize parameter–response relationships with maximum prediction errors of 18.69% (residual stress) and 12.27% (cutting force), showing good engineering applicability. The findings provide theoretical and experimental foundations for multi-parameter optimization in aluminum alloy milling and residual stress/cutting force control, with satisfactory practical effectiveness. Full article

Background: Attachments are essential components in clear aligner therapy, enhancing retention and improving the predictability of tooth movements. Mechanical and wear properties of the composite resins used for attachment reproduction are critical to maintaining their integrity and shape over time. This study aimed to evaluate and compare the mechanical properties, thermal behavior, and wear performance of the hybrid composite Aligner Connect (AC) and the flowable resin (Connect Flow, CF). Methods: Twenty samples (ten AC and ten CF) were reproduced. All specimens underwent differential scanning calorimetry (DSC), combustion analysis, flat instrumented indentation, compression stress relaxation tests, and tribological analysis. A 3D wear profile reconstruction was performed to assess wear surfaces. Results: DSC and combustion analyses revealed distinct thermal transitions, with CF showing significantly lower Tg values (103.8 °C/81.4 °C) than AC (110.8 °C/89.6 °C) and lower residual mass after combustion (23% vs. 61%), reflecting reduced filler content and greater polymer mobility. AC exhibited superior mechanical properties, with higher maximum load (585.9 ± 22.36 N) and elastic modulus (231.5 ± 9.1 MPa) than CF (290.2 ± 5.52 N; 156 ± 10.5 MPa). Stress relaxation decrease was less pronounced in AC (18 ± 4%) than in CF (20 ± 4%). AC also showed a significantly higher friction coefficient (0.62 ± 0.060) than CF (0.55 ± 0.095), along with greater wear volume (0.012 ± 0.0055 mm³ vs. 0.0070 ± 0.0083 mm³) and maximum depth (36.88 ± 3.642 µm vs. 17.91 ± 3.387 µm). Surface roughness before wear was higher for AC (Ra, 0.577 ± 0.035 µm; Rt, 4.369 ± 0.521 µm) than for CF (Ra, 0.337 ± 0.070 µm; Rt, 2.862 ± 0.549 µm). After wear tests, roughness values converged (Ra, 0.247 ± 0.036 µm for AC; Ra, 0.236 ± 0.019 µm for CF) indicating smoothened and similar surfaces for both composites. Conclusions: The hybrid nanocomposite demonstrated greater properties in terms of stiffness, load-bearing capacity, and structural integrity when compared with flowable resin. Its use may ensure more durable attachment integrity and improved aligner–tooth interface performance over time. Full article

Background: Charcot-Marie-Tooth (CMT) disease is a hereditary motor and sensory neuropathy that affects foot morphology and gait patterns, potentially leading to abnormal plantar pressure distribution. This systematic review synthesizes the existing literature examining plantar pressure characteristics in CMT patients. Methods: A comprehensive search was conducted across PubMed, Scopus, and Web of Science databases. Risk of bias was assessed using the Newcastle–Ottawa Scale. Results: Six studies comprising 146 patients were included. Four studies employed dynamic baropodometry, and two used in-shoe pressure sensors to evaluate the main plantar pressure parameters. The findings were consistent across different populations and devices, with a characteristic plantar-pressure profile of marked midfoot off-loading with peripheral overload at the forefoot and rearfoot, often accompanied by a lateralized center-of-pressure path and a prolonged pressure–time exposure. These alterations reflect both structural deformities and impaired neuromuscular control. Interventional studies demonstrated a load redistribution of pressure after corrective surgery, though residual lateral overload often persists. Conclusions: Plantar pressure mapping seems to be a valuable tool to identify high-pressure zones of the foot in order to personalize orthotic treatment planning, to objectively monitor disease progression, and to evaluate therapeutic efficacy. Further longitudinal studies with standardized protocols are needed to confirm these results. Full article

Caragana korshinskii Kom. (CKB), widely cultivated in Inner Mongolia, China, has potential for silage feed development due to its favorable nutritional characteristics, including a crude protein content of 14.2% and a neutral detergent fiber content below 55%. However, its vascular bundle fiber structure limits the efficiency of lactic acid conversion and negatively impacts silage quality, which can be improved through mechanical crushing. Currently, conventional crushing equipment generally suffers from uneven particle size distribution, high energy consumption, and low processing efficiency. In this study, a layered aggregate model was constructed using the discrete element method (DEM), and the Hertz–Mindlin with Bonding contact model was employed to characterize the heterogeneous mechanical properties between the epidermis and the core. Model accuracy was enhanced through reverse engineering and a multi-particle-size filling strategy. Key parameters were optimized via a Box–Behnken experimental design, with a core normal stiffness of 7.37 × 10¹¹ N·m⁻¹, a core shear stiffness of 9.46 × 10¹⁰ N·m⁻¹, a core shear stress of 2.52 × 10⁸ Pa, and a skin normal stiffness of 4.01 × 10⁹ N·m⁻¹. The simulated values for bending, tensile, and compressive failure forces had relative errors of less than 10% compared to experimental results. The results showed that rectangular hammers, due to their larger contact area and more uniform stress distribution, reduced the number of residual bonded contacts by 28.9% and 26.5% compared to stepped and blade-type hammers, respectively. Optimized rotational speed improved dynamic crushing efficiency by 41.3%. The material exhibited spatial heterogeneity, with the mass proportion in the tooth plate impact area reaching 43.91%, which was 23.01% higher than that in the primary hammer crushing area. The relative error between the simulation and bench test results for the crushing rate was 6.18%, and the spatial distribution consistency reached 93.6%, verifying the reliability of the DEM parameter calibration method. This study provides a theoretical basis for the structural optimization of crushing equipment, suppression of circulation layer effects, and the realization of low-energy, high-efficiency processing. Full article

Background: In modern dentistry, alveolar socket preservation after tooth extraction plays a critical role in maintaining the alveolar ridge for future dental implants. This retrospective clinical study evaluated bone-level changes 15 years after immediate implant placement, coupled with alveolar ridge preservation. Methods: Fifty non-smoking patients aged 25 to 75 (30 males and 20 females) who underwent single-implant rehabilitation in both anterior and posterior regions of the upper and lower jaws were included. The study examined bone levels and implant survival over time, using standardized intraoral radiographs at 1, 5, and 15 years post-loading. Implants were placed immediately after atraumatic extraction, and the residual gap was grafted with bovine hydroxyapatite and covered with a collagen membrane. The primary outcome was bone-level stability, while secondary outcomes included implant failure. No temporary crowns or removable dentures were provided during healing. Radiographs were digitized for detailed analysis. Results: The results for 50 patients with immediate implant placement showed that bone-resorption levels were significantly higher in the upper jaw than in the lower jaw. Conclusions: Posterior implants exhibited greater bone loss than anterior implants, particularly at 1 year and 15 years, while no implant failures occurred. Full article

To address poor film pickup, incomplete soil–film separation, and high soil content in conventional residual film recovery machines, this study designed a belt-tooth type residual film recovery machine. Its core component integrates flexible belts with nail-teeth, providing both overload protection and efficient conveying. EDEM simulations compared film pickup performance across tooth profiles, identifying an optimal structure. Based on the kinematics and mechanical properties of residual film, a film removal mechanism and packing device were designed, incorporating partitioned packing belts to reduce soil content rate in the collected film. Using Box–Behnken experimental design, response surface methodology analyzed the effects of machine forward speed, film-lifting tooth penetration depth, and pickup belt inclination angle. Key findings show: forward speed, belt angle, and tooth depth (descending order) primarily influence recovery rate; while tooth depth, belt angle, and forward speed primarily affect soil content rate. Multi-objective optimization in Design-Expert determined optimal parameters: 5.2 km/h speed, 44 mm tooth depth, and 75° belt angle. Field validation achieved a 90.15% recovery rate and 5.86% soil content rate. Relative errors below 2.73% confirmed the regression model’s reliability. Compared with common models, the recovery rate has increased slightly, while the soil content rate has decreased by more than 4%, meeting the technical requirements for resource recovery of residual plastic film. Full article

To address the limitations in time–frequency feature representation of shearer arm gear faults and the issues of parameter redundancy and low training efficiency in standard convolutional neural networks (CNNs), this study proposes a diagnostic method based on an improved S-transform and a Depthwise Separable Convolutional Neural Network (DSCNN). First, the improved S-transform is employed to perform time–frequency analysis on the vibration signals, converting the original one-dimensional signals into two-dimensional time–frequency images to fully preserve the fault characteristics of the gear. Then, a neural network model combining standard convolution and depthwise separable convolution is constructed for fault identification. The experimental dataset includes five gear conditions: tooth deficiency, tooth breakage, tooth wear, tooth crack, and normal. The performance of various frequency-domain and time-frequency methods—Wavelet Transform, Fourier Transform, S-transform, and Gramian Angular Field (GAF)—is compared using the same network model. Furthermore, Grad-CAM is applied to visualize the responses of key convolutional layers, highlighting the regions of interest related to gear fault features. Finally, four typical CNN architectures are analyzed and compared: Deep Convolutional Neural Network (DCNN), InceptionV3, Residual Network (ResNet), and Pyramid Convolutional Neural Network (PCNN). Experimental results demonstrate that frequency–domain representations consistently outperform raw time-domain signals in fault diagnosis tasks. Grad-CAM effectively verifies the model’s accurate focus on critical fault features. Moreover, the proposed method achieves high classification accuracy while reducing both training time and the number of model parameters. Full article

Introduction: Successful root canal therapy relies on thorough cleaning and disinfection to eliminate microorganisms and residual pulp tissue. Advanced irrigation activation techniques, including Sonic, Ultrasonic, and Diode Laser activation, have improved cleaning efficacy, bacterial reduction, smear layer removal, and irrigant hydrodynamics. On the other hand, these irrigation activation techniques may lead to a temperature rise that may risk the surrounding periodontal tissue. Thus, this study aimed to investigate the temperature rise during different irrigation activation techniques at various time intervals and evaluate the efficacy of these techniques in removing biofilm-mimicking hydrogel BMH of a simulated root canal system in 3D-printed tooth models. Methods: Ten extracted human mandibular premolars, prepared to size 40/0.04 taper, and a hundred 3D-printed resin premolars with simulated main (0.25 mm) and lateral canals (0.15 mm at 3, 7, 11 mm from apex) were used; 50 of them were filled with biofilm-mimicking hydrogel (BMH). Five irrigation activation techniques were evaluated: Diode Laser, Ultrasonic, Sonic, XP-Finisher, and Control (n = 10). Temperature rises were measured on the extracted premolars after 30 and 60 s of activation using a thermographic camera in a controlled environment (23 ± 2 °C). Irrigant penetration, with and without BMH, was assessed in 3D-printed premolars using a 2.5% sodium hypochlorite-contrast medium mixture, visualized with a CMOS radiographic sensor. Penetration was scored (main canal: 3 points; lateral canals: 0–2 points) and analyzed with non-parametric tests. Results: Diode Laser activation technique resulted in the highest temperature rise on the external root surface, followed by the Ultrasonic, with no statistically significant difference observed among the remaining groups. In terms of efficacy, Ultrasonic and Sonic activation achieved significantly greater irrigant penetration in samples without BMH, and greater BMH removal in samples with BMH, compared to Diode Laser, XP-Finisher, and Control groups. Conclusions: In this in vitro study, Diode Laser caused the highest temperature rise, followed by Ultrasonic, with significant increases from 30 to 60 s. Temperature rise did not significantly affect penetration or BMH removal. Ultrasonic and Sonic irrigation techniques achieved the highest depth of penetration (without BMH) and biofilm-mimicking Hydrogel removal (with BMH) compared to Diode Laser, XP-Finisher, and Control. Full article

Odontogenesis, the development of teeth, is a complex, multistage process that unfolds from early embryogenesis through tooth eruption and maturation. It serves as a classical model of organogenesis due to the intricate reciprocal interactions between cranial neural crest-derived mesenchyme and oral epithelium. This narrative review synthesizes current scientific knowledge on human tooth development, tracing the journey from the embryological origins in the first branchial arch to the formation of a fully functional tooth and its supporting structures. Key morphogenetic stages—bud, cap, bell, apposition, and root formation—are described in detail, highlighting the cellular events and histological features characterizing each stage. We discuss the molecular and cellular regulatory networks that orchestrate odontogenesis, including the conserved signaling pathways (Wnt, BMP, FGF, SHH, EDA) and transcription factors (e.g., PAX9, MSX1/2, PITX2) that drive tissue patterning and cell differentiation. The coordinated development of supporting periodontal tissues (cementum, periodontal ligament, alveolar bone, gingiva) is also examined as an integral part of tooth organogenesis. Finally, developmental anomalies (such as variations in tooth number, size, and form) and the fate of residual embryonic epithelial cells are reviewed to underscore the clinical significance of developmental processes. Understanding the normal course of odontogenesis provides crucial insight into congenital dental disorders and lays a foundation for advances in regenerative dental medicine. Full article

Background: Alveolar ridge preservation (ARP) following tooth extraction plays a vital role in maintaining ridge dimensions and supporting subsequent implant therapy. Objectives: This study histologically and radiographically evaluates the efficacy of techBiomat bone^®—a deproteinized bovine bone mineral (DBBM)—for alveolar ridge preservation (ARP), comparing the results of bone formation, residual graft particles, and nonmineralized tissue to those of spontaneous healing in human tooth sockets. Methods: A split-mouth study was conducted to evaluate the radiographic and histologic outcomes in human sockets with and without ARP. Results: A significant improvement in bone fill was observed compared to untreated sockets. Radiographically, 87% of the treated sockets demonstrated more than 75% bone fill, whereas only 7% of the untreated sockets did. Histologically, the percentage of new bone formation was greater in treated sockets (42%) than in untreated sockets (25%). The findings also highlighted a lower proportion of nonmineralized tissue in grafted sites, suggesting improved healing over spontaneous healing. The residual graft material in the treated sockets had a moderate resorption rate, with almost complete replacement by the host bone after six months. The use of techBiomat bone^® demonstrated promising results, with a resorption rate conducive to optimal bone regeneration, with less than 9% residual graft material remaining after six months. Conclusions: This study supports the efficacy of techBiomat bone^® graft material for ARP, highlighting its potential in maintaining ridge volume. Further studies with larger sample sizes are needed to confirm these findings. Full article

In the cotton fields in Xinjiang, residual film is present in the soil for a long period of time, leading to a decrease in the tensile strength of the residual film and increasing the difficulty of recycling. Existing technologies for residual film recovery focus on mechanical properties and ignore the dragging and tearing of residual film by cotton stubble. The effect of cotton straw–root stubble on residual film recovery can only be better determined by appropriate machine operating parameters, which are essential to improving residual film recovery. Through analyses of the pickup device, key parameters were identified, and a model was built by combining the FEM and SPH algorithms to simulate the interaction of nail teeth, residual film, soil and root stubble. The simulation revealed the force change law of residual film in root stubble-containing soil and the influence of root stubble. By simulating the changes in the characteristics of the residual film during the process, the optimum operating parameters for the nail teeth were determined: a forward speed of 1849.57 mm/s, a rotational speed of 5.5 r/s and a soil penetration angle of 30°. Under these optimized conditions, the maximum shear strain, pickup height (maximum deformation) and average peak stress of the residual film were 1293, 363.81 mm and 3.42 MPa, respectively. Subsequently, field trials were conducted to verify the change in the impact of the nail teeth at the optimized speed on the recovery of residual film in plots containing root stubble. The results demonstrated that when the root stubble height was 5–8 cm, the residual film averaged a recovery rate of 89.59%, with a dragging rate of only 4.10% at crossings. In contrast, 8–14 cm stubble plots showed an 82.86% average recovery and an 11.91% dragging rate. In plots with a root stubble height of 5–8 cm, compared with plots with a root stubble height of 8–14 cm, the recovery rate increased by 6.73%, and the dragging rate of residual film on root stubble decreased by 7.81%. The percentage of entangled residual film out of the total unrecovered film was 30.10% lower in the 5–8 cm stubble plots than in the 8–14 cm stubble plots. It was confirmed that the effect of cotton root stubble on residual film recovery could be reduced under appropriate machine operating parameters. This provides strong support and a theoretical and practical basis for future research on the correlation between root stubble and residual film and how to improve the residual film recovery rate. Full article