Cemental tear is a rare and indetectable condition unless obvious clinical signs present with the involvement of surrounding periodontal and periapical tissues. Due to its clinical manifestations similar to common dental issues, such as vertical root fracture, primary endodontic diseases, and periodontal diseases, as well as the low awareness of cemental tear for clinicians, misdiagnosis often occurs. The critical principle for cemental tear treatment is to remove torn fragments, and overlooking fragments leads to futile therapy, which could deteriorate the conditions of the affected teeth. Therefore, accurate diagnosis and subsequent appropriate interventions are vital for managing cemental tear. Novel diagnostic tools, including cone-beam computed tomography (CBCT), microscopes, and enamel matrix derivatives, have improved early detection and management, enhancing tooth retention. The implementation of standardized diagnostic criteria and treatment protocols, combined with improved clinical awareness among dental professionals, serves to mitigate risks of diagnostic errors and suboptimal therapeutic interventions. This expert consensus reviewed the epidemiology, pathogenesis, potential predisposing factors, clinical manifestations, diagnosis, differential diagnosis, treatment, and prognosis of cemental tear, aiming to provide a clinical guideline and facilitate clinicians to have a better understanding of cemental tear.
Humans ; Dental Cementum/injuries* ; Consensus ; Diagnosis, Differential ; Cone-Beam Computed Tomography ; Tooth Fractures/therapy*

Objective:To explore the clinical efficacy of the splenic vessel-oriented anatomical plane priority strategy in Da Vinci robotic Kimura distal pancreatectomy.Methods:A retrospective analysis was conducted on 26 patients who underwent robotic-assisted distal pancreatectomy at Zhejiang Provincial People’s Hospital from January 2019 to September 2024. The cohort included 7 male and 19 female patients, aged (49.3±16.7) years. Surgical outcomes, including operative time, intraoperative blood loss, postoperative complications, and hospital stay, were analyzed, and surgical techniques were summarized.Results:All 26 patients successfully completed the surgery. Pathological diagnoses included 5 cases of intraductal papillary mucinous neoplasm, 5 serous cystadenomas, 1 pancreatic neuroendocrine tumor, 6 solid pseudopapillary neoplasms, 4 mucinous cystic neoplasms, and 5 neuroendocrine tumors. The maximum tumor diameter was (2.3±1.1) cm, and the operative time was (183.2±77.4) min. The spleen preservation rate was 100% (26/26). Intraoperative blood loss was 50.0 (17.5, 125) ml, and postoperative hospital stay was (10.1±3.7) d. No Clavien-Dindo grade III or higher complications occurred. The post-operative pancreatic fistula (POPF) rate was 53.8% (14/26), including 38.5% (10/26) biochemical leak and 15.3% (4/26) grade B POPF, with no grade C POPF.Conclusion:The splenic vessel-oriented anatomical plane priority strategy in robotic-assisted spleen-preserving distal pancreatectomy (Kimura technique) is safe and feasible, significantly improving the spleen preservation rate.

Objective To investigate the effect of orthosis design parameters on correction of scoliosis and orthosis-trunk interface pressure.Methods A finite element model of scoliosis was constructed to simulate the assembly effect of the orthosis.The orthosis was divided into four loading areas(left rib,right rib,anterior-left and posterior-right area)to simulate six modification conditions.In Models 1,2 and 3,a fixed modification of 20 mm was applied on the anterior left and posterior right areas,while the displacement loads of 20,25 and 30 mm were applied on both the left rib and right rib areas.In Models 4,5 and 6,a fixed modification of 25 mm was applied on left rib and right rib areas,with the displacement loads of 15,20 and 25 mm applied on both anterior left and posterior right areas.The Cobb angle,apical vertebral rotation(AVR)and interface pressure were calculated.Results The correction of Cobb angle in Models 1,2 and 3 was 8.94°,15.62° and 17.91°,respectively,with AVR correction of 7.53°,6.69° and 5.87°,respectively.In Models 4,5 and 6,the correction of Cobb angle was 14.55°,15.62° and 16.09°,with AVR correction of 5.25°,6.69° and 8.63°,respectively.In Model 6,the correction rate of Cobb angle and AVR was 45.48%and 41.22%,respectively,with a maximum pressure of 26.51 kPa on orthosis-trunk interface,achieving the most significant outcome.Conclusions The modification of orthosis has a significant effect on the correction of Cobb and AVR angles.The loading on the left rib and right rib areas mainly affect the Cobb angle,while the loading on the anterior left and posterior right areas mainly affect the spinal axial-rotation.A modification of 25 mm on all loading areas achieves the optimal spinal correction.This study provides the quantitative data for orthosis design.

Objective To investigate the effect of orthosis design parameters on correction of scoliosis and orthosis-trunk interface pressure.Methods A finite element model of scoliosis was constructed to simulate the assembly effect of the orthosis.The orthosis was divided into four loading areas(left rib,right rib,anterior-left and posterior-right area)to simulate six modification conditions.In Models 1,2 and 3,a fixed modification of 20 mm was applied on the anterior left and posterior right areas,while the displacement loads of 20,25 and 30 mm were applied on both the left rib and right rib areas.In Models 4,5 and 6,a fixed modification of 25 mm was applied on left rib and right rib areas,with the displacement loads of 15,20 and 25 mm applied on both anterior left and posterior right areas.The Cobb angle,apical vertebral rotation(AVR)and interface pressure were calculated.Results The correction of Cobb angle in Models 1,2 and 3 was 8.94°,15.62° and 17.91°,respectively,with AVR correction of 7.53°,6.69° and 5.87°,respectively.In Models 4,5 and 6,the correction of Cobb angle was 14.55°,15.62° and 16.09°,with AVR correction of 5.25°,6.69° and 8.63°,respectively.In Model 6,the correction rate of Cobb angle and AVR was 45.48%and 41.22%,respectively,with a maximum pressure of 26.51 kPa on orthosis-trunk interface,achieving the most significant outcome.Conclusions The modification of orthosis has a significant effect on the correction of Cobb and AVR angles.The loading on the left rib and right rib areas mainly affect the Cobb angle,while the loading on the anterior left and posterior right areas mainly affect the spinal axial-rotation.A modification of 25 mm on all loading areas achieves the optimal spinal correction.This study provides the quantitative data for orthosis design.

Objective:To explore the clinical efficacy of the splenic vessel-oriented anatomical plane priority strategy in Da Vinci robotic Kimura distal pancreatectomy.Methods:A retrospective analysis was conducted on 26 patients who underwent robotic-assisted distal pancreatectomy at Zhejiang Provincial People’s Hospital from January 2019 to September 2024. The cohort included 7 male and 19 female patients, aged (49.3±16.7) years. Surgical outcomes, including operative time, intraoperative blood loss, postoperative complications, and hospital stay, were analyzed, and surgical techniques were summarized.Results:All 26 patients successfully completed the surgery. Pathological diagnoses included 5 cases of intraductal papillary mucinous neoplasm, 5 serous cystadenomas, 1 pancreatic neuroendocrine tumor, 6 solid pseudopapillary neoplasms, 4 mucinous cystic neoplasms, and 5 neuroendocrine tumors. The maximum tumor diameter was (2.3±1.1) cm, and the operative time was (183.2±77.4) min. The spleen preservation rate was 100% (26/26). Intraoperative blood loss was 50.0 (17.5, 125) ml, and postoperative hospital stay was (10.1±3.7) d. No Clavien-Dindo grade III or higher complications occurred. The post-operative pancreatic fistula (POPF) rate was 53.8% (14/26), including 38.5% (10/26) biochemical leak and 15.3% (4/26) grade B POPF, with no grade C POPF.Conclusion:The splenic vessel-oriented anatomical plane priority strategy in robotic-assisted spleen-preserving distal pancreatectomy (Kimura technique) is safe and feasible, significantly improving the spleen preservation rate.

Objective:Based on " the surveillance, epidemiology, and end results" (SEER) database, we constructed a nomogram model for predicting cancer-specific survival time (CSST) in patients with T2 stage gallbladder cancer.Methods:Clinical data on 486 patients with T2 stage gallbladder cancer between 2018 and 2020 were retrospectively collected from the SEER database. The cohort comprised 147 male and 339 female patients with the age at diagnosis of (70±13) years. Clinical information including age, gender, tumor size, tumor stage, surgical type, number of lymph node dissection, postoperative treatment, and patients prognosis were extracted from the SEER database. We analyzed the factors influencing CSST in patients with T2 stage gallbladder cancer using Cox risk-proportional regression. The nomogram model was constructed based on independent risk factors obtained from multivariate Cox regression analysis, and the area under curve (AUC) of receiver operating characteristic curves (ROC) were used to evaluate the predictive accuracy of the nomogram model, while calibration plots, decision curve analysis, and clinical impact curves were used to evaluate the model's practicality and effectiveness.Results:The results of multivariate Cox regression analysis showed that patients with tumor size ≥30 mm ( HR=1.775, 95% CI: 1.123-2.806), AJCC stage ⅢB ( HR=6.083, 95% CI: 2.961-12.495), 1-3 lymph node dissection ( HR=6.139, 95% CI: 2.876-13.106), no postoperative chemotherapy ( HR=1.743, 95% CI: 1.096-2.771) had a higher risk of short CSST (all P<0.05). A nomogram model for predicting CSST was constructed based on the above risk factors, and the AUC of the ROC of which for predicting 1-year and 2-year CSST in patients with T2 stage gallbladder cancer was 0.778 and 0.696, respectively. Calibration plots demonstrated excellent collinearity between predicted and actual probabilities. Decision curve analysis and clinical impact curves confirmed high net benefit and clinical validity of the nomogram model. Conclusions:The tumor size ≥30 mm, AJCC stage ⅢB, 1-3 lymph node dissection and no postoperative chemotherapy are risk factors for short CSST in patients with T2 gallbladder cancer. The nomogram model based on the above risk factors have excellent performance in predicting CSST in patients with T2 stage gallbladder cancer.

Objective:Based on " the surveillance, epidemiology, and end results" (SEER) database, we constructed a nomogram model for predicting cancer-specific survival time (CSST) in patients with T2 stage gallbladder cancer.Methods:Clinical data on 486 patients with T2 stage gallbladder cancer between 2018 and 2020 were retrospectively collected from the SEER database. The cohort comprised 147 male and 339 female patients with the age at diagnosis of (70±13) years. Clinical information including age, gender, tumor size, tumor stage, surgical type, number of lymph node dissection, postoperative treatment, and patients prognosis were extracted from the SEER database. We analyzed the factors influencing CSST in patients with T2 stage gallbladder cancer using Cox risk-proportional regression. The nomogram model was constructed based on independent risk factors obtained from multivariate Cox regression analysis, and the area under curve (AUC) of receiver operating characteristic curves (ROC) were used to evaluate the predictive accuracy of the nomogram model, while calibration plots, decision curve analysis, and clinical impact curves were used to evaluate the model's practicality and effectiveness.Results:The results of multivariate Cox regression analysis showed that patients with tumor size ≥30 mm ( HR=1.775, 95% CI: 1.123-2.806), AJCC stage ⅢB ( HR=6.083, 95% CI: 2.961-12.495), 1-3 lymph node dissection ( HR=6.139, 95% CI: 2.876-13.106), no postoperative chemotherapy ( HR=1.743, 95% CI: 1.096-2.771) had a higher risk of short CSST (all P<0.05). A nomogram model for predicting CSST was constructed based on the above risk factors, and the AUC of the ROC of which for predicting 1-year and 2-year CSST in patients with T2 stage gallbladder cancer was 0.778 and 0.696, respectively. Calibration plots demonstrated excellent collinearity between predicted and actual probabilities. Decision curve analysis and clinical impact curves confirmed high net benefit and clinical validity of the nomogram model. Conclusions:The tumor size ≥30 mm, AJCC stage ⅢB, 1-3 lymph node dissection and no postoperative chemotherapy are risk factors for short CSST in patients with T2 gallbladder cancer. The nomogram model based on the above risk factors have excellent performance in predicting CSST in patients with T2 stage gallbladder cancer.

Finite element method (FEM) was used to investigate the biomechanical properties of three types of surgical fixations of U-shaped sacral fractures. Based on a previously established and validated complete lumbar-pelvic model, three models of surgical fixations of U-shaped sacral fractures were established: ① S1S2 passed through screw (S1S2), ② L4-L5 pedicle screw + screw for wing of ilium (L4L5 + IS), and ③ L4-L5 pedicle screw + S1 passed through screw + screw for wing of ilium (L4L5 + S1 + IS). A 400 N force acting vertically downward, along with torque of 7.5 N·m in different directions (anterior flexion, posterior extension, axial rotation, and axial lateral bending), was exerted on the upper surface of L4. Comparisons were made on differences in separation of the fracture gap and maximum stress in sitting and standing positions among three fixation methods. This study showed that: for values of separation of the fracture gap produced by different operation groups in different positions, L4L5 + S1 + IS was far less than L4L5 + IS and S1S2. For internal fixators, the maximum stress value produced was: L4L5 + IS > L4L5 + S1 + IS > S1S2. For the intervertebral disc, the maximum stress value produced by S1S2 is much larger than that of L4L5 + S1 + IS and L4L5 + IS. In a comprehensive consideration, L4L5 + S1 + IS could be prioritized for fixation of U-shaped sacral fractures. The objective of this research is to compare the biomechanical differences of three different internal fixation methods for U-shaped sacral fractures, for the reference of clinical operation.
Biomechanical Phenomena ; Finite Element Analysis ; Fracture Fixation ; methods ; Humans ; Lumbar Vertebrae ; Pedicle Screws ; Sacrum ; injuries ; Spinal Fractures ; surgery ; Spinal Fusion

Objective To study the biomechanical influence of posterior laminectomy with varying extent on adjacent segment after lumbar interbody fusion. Methods Three finite element models of lumbar posterior fusion were developed based on the validated intact lumbar model. These models were: posterior fusion with bi-lateral incision of facet joint (Bi-TLIF），inferior partly incision of laminar (PLIF)，total laminectomy (LAM-PLIF). The range of motion (ROM), intradiscal pressure (IDP), facet joint contact force (FJF) of adjacent segment of fusion models under various loading were compared with the intact model. The follower load of 400 N under 7.5 N·m torque was exerted on superior endplate of L1 segment. The 6-DOF (degree of freedom) of sacroiliac joint surface was constrained during loading. ResultsDuring flexion, obvious biomechanical changes of superior adjacent segment (L3-4) were found in Bi-TLIF, PLIF, LAM-PLIF surgery groups. Compared with the intact model, the ROM in Bi-TLIF, PLIF, LAM-PLIF group increased by 1.0%, 9.3%, 24.5%, respectively, while IDP in the above fusion groups increased by 1.4%, 4.3%, 10.0%，respectively. These changes were not obvious in other postures. For FJF, the Bi-TLIF and PLIF group showed obvious increasing effect on L3-4 segment, while almost had no effect on L5-S1 segment. Conclusions Laminectomy increased ROM, IDP and FJF of adjacent segment (especially superior adjacent segment) after posterior lumbar fusion, which might increase the risk of adjacent segment degeneration. This biomechanical effect was more obvious with the increase in incision range of laminar. Therefore, preserving more posterior complex during decompression has a positive effect on preventing adjacent segment degeneration (ASD) following lumbar fusion surgeries.

We observed the effect of vibration parameters on lumbar spine under different vibration conditions using finite element analysis method in our laboratory. In this study, the CT-images of L1-L5 segments were obtained. All images were used to develop 3D geometrical model using the Mimics10. 01 (Materialise, Belgium). Then it was modified using Geomagic Studio12. 0 (Raindrop Geomagic Inc. USA). Finite element (FE) mesh model was generated by Hypermesh11. 0 (Altair Engineering, Inc. USA) and Abaqus. Abaqus was used to calculate the stress distribution of L1-L5 under different vibration conditions. It was found that in a vibration cycle, tensile stress was occurred on lumbar vertebra mainly. Stress distributed evenly and stress concentration occurred on the left rear side of the upper endplate. The stress had no obvious changes under different frequencies, but the stress was higher when amplitude was greater. In conclusion, frequency and amplitude parameters have little effect on the stress distribution in vertebra. The stress magnitude is positively correlated with the amplitude.
Biomechanical Phenomena ; Finite Element Analysis ; Humans ; Lumbar Vertebrae ; physiology ; Vibration