Introduction: We aimed to evaluate the immediate and long-term micro-tensile bond strength (μTBS) of three adhesive systems under simulated pulpal pressure (PP). Methods: Flat dentin surfaces were prepared from 72 extracted human third molars and assigned to three adhesive systems ( n = 24): a 2-step etch-and-rinse, a 2-step self-etch, and a 1-step self-etch adhesive. Bonding and storage performed under 0 or 15 mmH₂O PP. Resin composite build-ups were placed, and μTBS was measured immediately, after 24 h, and after 3 months of water storage. Results: μTBS values at immediate and 3-month evaluations were lower than those at 24 h. Positive PP significantly reduced the immediate μTBS of the 1-step self-etch adhesive. Prolonged water storage decreased μTBS for all adhesives, whereas reduced dentinal fluid flow improved 3-month μTBS. Conclusion: Simulated PP and long-term water storage adversely affect dentin bonding. Reducing dentinal fluid flow during bonding enhances long-term bond durability.
Introduction: We aimed to develop and validate a nonradiographic deep learning model to assess skeletal maturity among Iraqi children using smartphones. Methods: We followed 499 Iraqi children (ages 8–15), collecting five smartphone images of their hands and teeth alongside tabular data points. Our “Stacking_v4” model (a hybrid of convolutional neural networks and XGBoost) was trained to sort participants into three growth spurt stages, using the middle phalanx of the third finger method as our ground truth for comparison. Results: The model achieved 96.00% accuracy (95% confidence interval: 90.1%–98.9%) on the test set. F1 scores for the various growth stages (ranging from 0.949 to 0.968) suggest the model is quite steady across the board. Interestingly, the data showed a consistent 96.00% accuracy for both boys and girls, which may indicate gender fairness. Conclusion: While more testing is likely needed, this approach appears to offer a safe, low-cost alternative for Iraqi orthodontists. Using accessible technology like smartphones might bridge the gap in clinical decision-making without traditional radiation risks.
Introduction: Occupational exposure from preapical X‑rays may elevate thyroid radiation dose in dentists. This study compared thyroid gland exposure resulting from portable vs. fixed intra‑oral X‑ray devices. Methods: A cross‑sectional field study measured thyroid dose by thermoluminescent dosimeters placed on the anterior neck (thyroid level) using portable and fixed oral X‑ray units during routine preapical imaging. Results: We found a statistically significant difference regarding mean thyroid dose (mGy) between the fixed devices group (n=30, mean = 0.00219 ± 3.84e − 4) and portable devices group ( n = 30, mean = 0.00536 ± 9.58e − 4) ( P < 0.001). Linear regression model (overall model test: P < 0.001) showed the device type and radiographic technique were significant predictors for thyroid dose ( P < 0.05), while collimation technique and usage of thyroid collar were not significant predictors ( P > 0.05). Conclusions: Portable units pose a higher thyroid exposure risk to dentists.
Introduction: Conventional orthodontic brackets are limited by slot dimensional inaccuracies, dependence on wire bending, and a lack of individualization. Fully customized CAD/CAM systems overcome these challenges but remain costly, complex, and inaccessible in many clinical settings. The Hypothesis: The hybrid bracket system (HBS) is proposed as a modular, two-piece semicustomized orthodontic bracket. The bonded base remains fixed on the tooth, while detachable faceplates carrying the slot can be interchanged to introduce torque, tip, in–out, or vertical corrections. This design integrates the affordability of conventional appliances with the adaptability of customized systems, aiming to reduce wire bending, minimize rebonding, and preserve enamel integrity. Evaluation of the Hypothesis: The modular configuration of HBS allows orthodontists to implement biomechanical corrections directly through faceplate replacement, enabling mesial or distal tipping, extrusion or intrusion, positive or negative torque, and in–out adjustments. This approach reduces chairside time, enhances treatment standardization, and minimizes enamel damage from rebonding. Advances in 3D printing and CNC milling make high-precision modular components feasible at scale while maintaining cost efficiency. Nevertheless, HBS remains a conceptual framework. Its clinical value requires validation through laboratory mechanical testing, finite element modeling, and randomized controlled trials to assess mechanical durability, wear resistance, bracket profile, and patient comfort.
Introduction: We aimed to assess the correlation between vertical dimension of occlusion measured by mandibular rest position (two-dots facial measurement) and ANS-Xi-Pm cephalometric angle. Methods: Patients classified as Class I or II Kennedy were selected, aged between 30 and 50 years, and without signs or symptoms related to joint or muscular dysfunction. The vertical dimension was measured by two methods as follows: first, the two-dots facial measurement technique. The second method was by taking lateral cephalometric X-rays with measurement of ANS-Xi-Pm angle. Results: Data analysis with Pearson’s correlation coefficient showed a weak non-significant correlation between vertical dimension of occlusion measured by mandibular rest position (two-dots facial measurement) and ANS-Xi-Pm cephalometric angle ( r : 0.193, P -value: 0.415). Conclusion: More studies with larger sample sizes are required to reach a conclusion regarding the clinical effectiveness of the ANS-Xi-Pm cephalometric angle in determining the occlusal vertical dimension.
