Injectable bone cement cannulated pedicle screw for lumbar degenerative disease in osteoporosis - clinical follow-up of over 5 years.

OBJECTIVE: The aim of this study is to evaluate the clinical efficacy of injectable cemented hollow pedicle screw (CICPS) in the treatment of osteoporotic lumbar degenerative diseases through a large sample long-term follow-up study. Additionally, we aim to explore the risk factors affecting interbody fusion. METHODS: A total of 98 patients who underwent CICPS for transforaminal lumbar interbody fusion (TLIF) for osteoporotic lumbar degenerative disease from March 2011 to September 2017 were analyzed. X-ray and electronic computed tomography (CT) imaging data were collected during preoperative, postoperative, and follow-up periods. The data included changes in intervertebral space height (ΔH), screw failure, cement leakage (CL), and intervertebral fusion. The patients were divided into two groups based on their fusion status one year after surgery: satisfied group A and dissatisfied group B. Surgical data such as operation time, intraoperative bleeding volume and surgical complications were recorded, and visual analog scale (VAS) and Oswestry disability index (ODI) were used to evaluate the improvement of lumbar and leg pain. RESULTS: The mean follow-up time was 101.29 months (ranging from 70 to 128 months). A total of 320 CICPS were used, with 26 screws (8.13%) leaking, 3 screws (0.94%) experiencing cement augmentation failure, and 1 screw (0.31%) becoming loose and breaking. The remaining screws were not loose or pulled out. Female gender, decreased bone density, and CL were identified as risk factors affecting interbody fusion (P < 0.05). Early realization of interbody fusion can effectively prevent the loss of intervertebral space height (P < 0.05) and maintain the surgical treatment effect. Both VAS and ODI scores showed significant improvement during the follow-up period (P < 0.05). Binary logistic regression analysis revealed that decreased bone density and cement leakage were risk factors for prolonged interbody fusion. CONCLUSIONS: The results of long-term follow-up indicate that PMMA enhanced CICPS has unique advantages in achieving good clinical efficacy in the treatment of osteoporosis lumbar degenerative diseases. Attention should be paid to identify female gender, severe osteoporosis, and CL as risk factors affecting interbody fusion.

Second-generation bone cement-injectable cannulated pedicle screws for osteoporosis: biomechanical and finite element analyses.

BACKGROUND: Biomechanical and finite element analyses were performed to investigate the efficacy of second-generation bone cement-injectable cannulated pedicle screws (CICPS) in osteoporosis. METHODS: This study used the biomechanical test module of polyurethane to simulate osteoporotic cancellous bone. Polymethylmethacrylate (PMMA) bone cement was used to anchor the pedicle screws in the module. The specimens were divided into two groups for the mechanical tests: the experimental group (second-generation CICPS) and control group (first-generation CICPS). Safety was evaluated using maximum shear force, static bending, and dynamic bending tests. Biomechanical stability evaluations included the maximum axial pullout force and rotary torque tests. X-ray imaging and computed tomography were used to evaluate the distribution of bone cement 24 h after PMMA injection, and stress distribution at the screw fracture and screw-cement-bone interface was assessed using finite element analysis. RESULTS: Mechanical testing revealed that the experimental group (349.8 ± 28.6 N) had a higher maximum axial pullout force than the control group (277.3 ± 8.6 N; P < 0.05). The bending moments of the experimental group (128.5 ± 9.08 N) were comparable to those of the control group (113.4 ± 20.9 N; P > 0.05). The screw-in and spin-out torques of the experimental group were higher than those of the control group (spin-in, 0.793 ± 0.015 vs. 0.577 ± 0.062 N, P < 0.01; spin-out, 0.764 ± 0.027 vs. 0.612 ± 0.049 N, P < 0.01). Bone cement was mainly distributed at the front three-fifths of the screw in both groups, but the distribution was more uniform in the experimental group than in the control group. After pullout, the bone cement was closely connected to the screw, without loosening or fragmentation. In the finite element analysis, stress on the second-generation CICPS was concentrated at the proximal screw outlet, whereas stress on the first-generation CICPS was concentrated at the screw neck, and the screw-bone cement-bone interface stress of the experimental group was smaller than that of the control group. CONCLUSION: These findings suggest that second-generation CICPS have higher safety and stability than first-generation CICPS and may be a superior choice for the treatment of osteoporosis.

The Mediating Effects of Nutritional Status on the Relationship between Number of Residual Teeth and Cognitive Function among Older Adults: A Cross-Sectional Multicenter Study.

The underlying mechanisms of the relationship between the number of teeth and cognition is still unclear. We aimed to construct a mediation model between the number of residual teeth and cognitive function, using nutritional status as a mediating factor. This study was completed using the West China Health and Aging Trend cohort. A total of 6634 multi-ethnic older adults, aged 50 years or older, were included. This study measured cognitive function using the Short-Portable Mental Status Questionnaire, and nutritional status was assessed using the Mini Nutritional Assessment-Short Form. The mediation analysis examined the potential mediating role of nutritional status. The pathway analysis was supplemented and validated using the structural equation modelling framework. Multiple linear regression demonstrated that a higher number of residual teeth was correlated with enhanced cognitive function (ß = -0.15; 95% CI: -0.19 to -0.111). The mediation model, from the number of residual teeth to cognitive impairment, was partially mediated by nutritional status (ß = -0.0608; 95% CI: -0.0762 to -0.0461). The proportion of the mediating effect, expressed as a percentage, was 40.66%. Furthermore, the estimated coefficients for the number of residual teeth and nutritional status varied across ethnic groups. This study indicated that enhancing the nutrition of older adults could reduce the adverse effects of the number of residual teeth on cognitive function among older adults.

Orthodontic Treatment Based on Wearable Mirror-Type Oral Prosthetic Tongue Flap without Bracket Correction.

White teeth can make people full of confidence and satisfy the concept of modern life from the love of beauty. Due to the fusion of computer-aided design and teeth, invisible orthodontics has become the focus of research. Invisible orthodontic treatment technology can predict the results of orthodontics. How to automatically calculate the position and posture of the teeth in the middle stage of orthodontics is the key point of the treatment technology. In order to solve this problem, this article is divided into two parts to start research. Aiming at the problem of tooth orthodontic path planning, quaternion is used to define the tooth posture, combined with the initial posture and target posture of the tooth. A two-stage method is given to plan a collision-free path for the orthodontic tooth. In the first stage, the quaternion spherical linear interpolation and position linear interpolation are used to obtain the intermediate posture of the tooth during orthodontics, and the initial value of the orthodontic stage is obtained, and the obtained intermediate posture is used as a sampling node to apply to the next stage. In the second phase, considering the problem of orthodontic collision and interference, a scheme for calculating the priority of orthodontics is proposed, and the random node expansion part in the RRT (Rapid-exploration Random Tree) algorithm is improved. The initial value of the orthodontic phase is used to calculate the initial value of the iteration. Finally, a path with no collision and the least number of orthodontic stages is searched from the random tree of each tooth node. The experimental results and analysis show that this method can quickly and effectively solve the orthodontic path of teeth, and it is used clinically. The clasp-free invisible correction technology pushes the molars far away to leave gaps for treating patients with mild to moderate overcrowding. The treatment time should be reduced by at least 30%; the stability of the gaps and the long-term healing effect of the treatment provide a reference.

Mechanical strong stretchable conductive multi-stimuli-responsive nanocomposite double network hydrogel as biosensor and actuator.

Multi-stimuli- responsive mechanical strong stretchable hydrogel has grabbed extensive attention in recent years. Here, a novel stretchable conductive biocompatible near-infrared light(NIR)-/thermal-/pH-/ionic concentration- responsive carboxymethyl chitosan (CMCTs)/graphene oxide (GO)/poly(N-isopropylacrylamide)(PNIPAm) nanocomposite double network hydrogel was fabricated through a simple one-pot in situ free radical polymerization, which is initiated by ultraviolet (UV) light and using N-(3-dimethylaminopropyl)-N-ethylcarbodiimidehydrochloride (EDC) and N,N'-bis(acryloyl)cystamine (BAC) as cross-linkers respectively, instead of toxic organic molecules. When the concentration of CMCTs, GO, EDC and BAC is 22.50, 0.103, 7.50 and 0.467 mg/mL respectively, the obtained hydrogel sample owns the highest tensile strength of 1046 kPa at failure strain of 1286% and a corresponding compressive stress of 2.37 MPa at deformation of 90%. Besides, these hydrogels have an obvious pH-/thermal-/ionic concentration-responsive properties depending on the concentration of the above mentioned factors, and their good conductive property makes them as candidate material for healthcare biosensors. Finally, we attempt to design a novel thermal-/NIR-responsive double network structure bilayer hydrogel, which has the potential use as remote actuator in dangerous places in the future.

Association between the number of teeth and frailty among Chinese older adults: a nationwide cross-sectional study.

OBJECTIVES: To explore the association between the number of teeth and frailty among older Chinese adults using a nationally representative sample. DESIGN: Cross-sectional analysis was carried out using the 2014 wave data from the Chinese Longitudinal Healthy Longevity Survey, which used a targeted random-sampling design. SETTING: This research was conducted in communities from nearly half of the counties and cities in 22 out of 31 provinces throughout China. PARTICIPANTS: Of the 6934 interviewees aged ≥65 years, the final analysis included 3635 older adults who had completed the 2014 wave survey on the variables included in the study. PRIMARY AND SECONDARY OUTCOME MEASURES: Outcome variables included frailty, measured by the Frailty Index, and number of teeth. Covariates included demographic characteristics (ie, age, sex, co-residence, marital status, years of education and financial support), body mass index (BMI) and health behaviours (ie, smoking, drinking and exercise). A univariate logistic regression was used to test the factors associated with frailty. A multiple logistic regression model was used, using the frailty score as the dependent variable and the number of teeth together with significant covariates as the independent variables. RESULTS: The prevalence of frailty was 27.68%. The mean number of teeth present was 9.23 (SD=10.03). The multiple logistic regression showed that older adults' demographic variables, health behaviours, BMI, tooth number and chewing pain were significantly associated with frailty. After adjusting for the covariates, older adults with fewer teeth had significantly higher odds of frailty than those with 20 or more teeth (no teeth: OR=2.07, 95% CI 1.53 to 2.80; 1 to 10 teeth: OR=1.77, 95% CI 1.31 to 2.38), except for older adults with 11 to 20 teeth (OR=1.30, 95% CI 0.93 to 1.82). CONCLUSIONS: The presence of fewer teeth is significantly associated with frailty status among older Chinese adults. Future studies are needed to explain the specific mechanisms underlying how oral health status is associated with frailty.