OBJECTIVE: To investigate the clinical efficacy of acrylic cement (PMMA) mixed with calcium sulfate combined with percutaneous kyphoplasty (PKP) in the treatment of osteoporotic fracture (OVCF). METHODS: The clinical data of 191 patients with OVCF treated with PKP from January 2020 to March 2021 were retrospectively analyzed. Among them, 82 patients with 94 vertebral bodies were treated with PMMA mixed with calcium sulfate as the observation group, and 109 patients with 125 vertebral bodies were treated with pure PMMA as the control group. Among the 82 patients in the observation group, there were 16 males and 66 females, with a mean age of (75.35±11.22) years old, including 36 thoracic vertebrae and 58 lumbar vertebrae. In the control group, there were 109 patients, 22 males and 87 females, with an average age of (74.51±9.21) years old, including 63 thoracic vertebrae and 62 lumbar vertebrae. The visual analog scale (VAS) before operation and 1 day, 3 months and 1 year after operation were calculated. The Oswestry disability index (ODI), Cobb's angle, vertebral body height and the probability of postoperative bone cement leakage were used to analyze the efficacy of the two groups. RESULTS: All the patients were followed up for more than one year. Compared with the control group, there was no significant difference in operation time, bleeding volume and bone cement injection volume between the two groups(P>0.05), while the leakage rate of bone cement was significantly lower in the observation group (P<0.05). In addition, there was no significant difference in VAS, ODI, Cobb angle, and vertebral body height between the two groups before operation, and 1 day, 3 months, and 1 year after operation (P>0.05), but each index was improved compared with that before operation (P<0.05). CONCLUSION PMMA mixed with calcium sulfate has equivalent efficacy in treating OVCF than PMMA alone, but can effectively reduce the probability of cement leakage.
Female ; Male ; Humans ; Aged ; Aged, 80 and over ; Middle Aged ; Polymethyl Methacrylate ; Calcium Sulfate/therapeutic use* ; Osteoporotic Fractures/surgery* ; Bone Cements/therapeutic use* ; Kyphoplasty ; Retrospective Studies ; Lumbar Vertebrae/surgery*

OBJECTIVE: With the help of finite element analysis, to explore the effect of proximal humeral bone cement enhanced screw plate fixation on the stability of internal fixation of osteoporotic proximal humeral fracture. METHODS: The digital model of unstable proximal humeral fracture with metaphyseal bone defect was made, and the finite element models of proximal humeral fracture bone cement enhanced screw plate fixation and common screw plate fixation were established respectively. The stress of cancellous bone around the screw, the overall stiffness, the maximum stress of the plate and the maximum stress of the screw were analyzed. RESULTS: The maximum stresses of cancellous bone around 6 screws at the head of proximal humeral with bone cement enhanced screw plate fixation were 1.07 MPa for No.1 nail, 0.43 MPa for No.2 nail, 1.16 MPa for No.3 nail, 0.34 MPa for No.4 nail, 1.99 MPa for No.5 nail and 1.57 MPa for No.6 nail. These with common screw plate fixation were:2.68 MPa for No.1 nail, 0.67 MPa for No.2 nail, 4.37 MPa for No.3 nail, 0.75 MPa for No.4 nail, 3.30 MPa for No.5 nail and 2.47 MPa for No.6 nail. Overall stiffness of the two models is 448 N/mm for bone cement structure and 434 N/mm for common structure. The maximum stress of plate appears in the joint hole:701MPa for bone cement structure and 42 0MPa for common structure. The maximum stress of screws appeared at the tail end of No.4 nail:284 MPa for bone cement structure and 240.8 MPa for common structure. CONCLUSION Through finite element analysis, it is proved that the proximal humerus bone cement enhanced screw plate fixation of osteoporotic proximal humeral fracture can effectively reduce the stress of cancellous bone around the screw and enhance the initial stability after fracture operation, thus preventing from penetrating out and humeral head collapsing.
Humans ; Finite Element Analysis ; Bone Cements ; Polymethyl Methacrylate ; Biomechanical Phenomena ; Shoulder Fractures/surgery* ; Fracture Fixation, Internal ; Humeral Head ; Bone Screws ; Bone Plates

There are many occupational risk factors in operating room work. Polymethyl methacrylate (PMMA) , as a kind of common bone filling and repairing material, is widely used in the fixation of artificial joints, oral braces and orthopedic prosthesis. However, PMMA will release methyl methacrylate (MMA) monomer when it is implanted into human tissues and polymerized to harden, which is toxic to the body. This paper analyzes harmful factors in using PMMA bone cement, and then explores corresponding occupational protection knowledge, in order to reduce the occurrence of occupational hazards related to PMMA bone cement and enhance the self-protection ability of the operation room medical staff.
Bone Cements/adverse effects* ; Humans ; Operating Rooms ; Polymethyl Methacrylate/adverse effects*

OBJECTIVE: From the perspective of clinical application to analyze the effectiveness and reliability of CPC/PMMA bone cement in percutaneous kyphoplasty (PKP) for the treatment of elderly patients with osteoporotic thoracolumbar fractures. METHODS: A retrospective analysis was performed on 62 patients with osteoporotic compression fracture of single-vertebral thoracic or lumbar segment who underwent PKP surgery and had a bone density less than or equal to -3.0 SD from February 2016 to December 2016. Among them, 23 patients were in CPC/PMMA group, with an average age of (77.6±2.2) years old, 39 patients in PMMA group, with an average age of (77.1±1.1) years old. The indexes between two groups were compared, including the visual analogue scale (VAS), height ratio of anterior vertebra (AVHR), local Cobb angle, cement leakage, new adjacent vertebral fracture(NAVF). RESULTS: There were no significant difference in gender, age, follow-up time and preoperative VAS, AVHR, local Cobb angle between two groups (>0.05), at the 1 day after operation, VAS, AVHR, local Cobb angle in all patients got obvious improvement (<0.05), which was no significant difference at 1 day after operation and final follow-up (>0.05). At the same time, there was no statistically significant difference in the incidence of new adjacent vertebral fracture and cement leakage (>0.05). The pain in both groups continued to improve at follow up after operation (<0.05), the local Cobb angle increased (<0.05) and AVHR decreased slightly (<0.05). However, the images of conventional methods (X-ray or CT) could not find signs about CPC degeneration and new bone ingrowth. CONCLUSION CPC/PMMA composite bone cement is safe and reliablein PKP for treatment of elderly patients with osteoporotic thoracolumbar fractures, which can effectively relieve pain and maintain vertebral body stability. It has the same curative effect as PMMA bone cement. It was worthy to research more in future, although no direct evidences support the CPC/PMMA composite bone cement can reduce the incidence of adjacent vertebral fracture, CPC degeneration or new bone ingrowth.
Aged ; Bone Cements ; Dinucleoside Phosphates ; Fractures, Compression ; Humans ; Kyphoplasty ; Osteoporotic Fractures ; Polymethyl Methacrylate ; Reproducibility of Results ; Retrospective Studies ; Spinal Fractures ; Treatment Outcome ; Vertebroplasty

Bone cement, consisting of polymethyl methacrylate, is a bioinert material used for prothesis fixation in joint arthroplasty. To treat orthopedic infections, such as periprosthetic joint infection, antibiotic-loaded bone cement (ALBC) was introduced into clinical practice. Recent studies have revealed the limitations of the antibacterial effect of ALBC. Moreover, with the increase in high infection risk patients and highly resistant microbes, more researches and modification of ALBC are required. This paper reviewed latest findings about ALBC for most popular and destructive pathogens, summarized the influence of antibiotic kind, drug dosage, application method, and environment towards characteristic of ALBC. Subsequently, new cement additives and clinical applications of ALBC in joint arthroplasty were also discussed.
Anti-Bacterial Agents/therapeutic use* ; Arthroplasty, Replacement, Knee ; Bone Cements ; Humans ; Polymethyl Methacrylate ; Prosthesis-Related Infections/drug therapy*

BACKGROUND: Recently, three-dimensional (3D) printing has been hailed as a disruptive technology in dentistry. Among 3D printers, a digital light processing (DLP) 3D printer has certain advantages, such as high precision and relatively low cost. Therefore, the latest trend in resin crown manufacturing is the use of DLP 3D printers. However, studies on the internal fitness of such resin crowns are insufficient. The recently introduced 3D evaluation method makes it possible to visually evaluate the error of the desired area. The purpose of this study is to evaluate the internal fitness of resin crowns fabricated a by DLP 3D printer using the 3D evaluation method.METHODS: The working model was chosen as the maxillary molar implant model. A total of 20 resin crowns were manufactured by dividing these into two groups. One group was manufactured by subtractive manufacturing system (PMMA), while the other group was manufactured by additive manufacturing system, which uses a DLP 3D printer. Resin crowns data were measured using a 3D evaluation program. Internal fitness was calculated by root mean square (RMS). The RMS was calculated using the Geomagic Verify software, and the mean and standard deviation (SD) were measured. For statistical analysis, IBM SPSS Statistics for Windows ver. 22.0 (IBM Corp., USA) was used. Then, independent t-test was performed between the two groups.RESULTS: The mean±SD of the RMS were 41.51±1.51 and 43.09±2.32 for PMMA and DLP, respectively. There was no statistically significant difference between PMMA and DLP.CONCLUSION: Evaluation of internal fitness of the resin crown made using a DLP 3D printer and subtractive manufacturing system showed no statistically significant differences, and clinically acceptable results were obtained.
Crowns ; Dentistry ; Imaging, Three-Dimensional ; Methods ; Molar ; Polymethyl Methacrylate ; Printing, Three-Dimensional

PURPOSE: The aim of this study was to investigate simulated localized and generalized wear of indirect composite resins used for implant supported provisional restorations. MATERIALS AND METHODS: The study investigated ten indirect composite resins. Two kinds of wear were simulated by 400,000 cycles in a Leinfelder-Suzuki (Alabama) machine. Localized wear was simulated with a stainless-steel ball bearing antagonist and generalized with a flat-ended stainless-steel cylinder antagonist. The tests were carried out in water slurry of polymethyl methacrylate beads. Wear was measured using a Proscan 2100 noncontact profilometer in conjunction with Proscan and AnSur 3D software. RESULTS: Both localized and generalized wear were significantly different (P<.05) among the indirect composite resins. SR Nexco and Gradia Plus showed significantly less wear than the other indirect composite resins. The rank order of wear was same in both types of wear simulation. CONCLUSION: Indirect composite resins are recommended when a provisional implant-supported restoration is required to function in place over a long period. Although only some indirect composite resins showed similar wear resistance to CAD/CAM composite resins, the wear resistance of all the indirect composite resins was higher than that of bis-acryl base provisional and polymethyl methacrylate resins.
Composite Resins ; Dental Prosthesis ; Dental Restoration Wear ; Polymethyl Methacrylate ; Water

PURPOSE: The aim of the present study was to evaluate the color changes of an autopolymerizing PMMA resin used for interim fixed restorations, reinforced with SiO2 nanoparticles. MATERIALS AND METHODS: Silica nanoparticles were blended with the PMMA resin powder through high-energy ball milling. Four shades of PMMA resin were used (A3, B3, C3, D3) and total color differences were calculated through the equations ΔEab= [(ΔL*)2 + (Δa*)2 + (Δb*)2]½ and Δ E 00 = [ Δ L ′ K L S L 2 + Δ C ′ K C S C 2 + Δ H ′ K H S H 2 + R T Δ C ′ K C S C Δ H ′ K H S H ] 1 / 2 . Statistically significant differences between ΔEab and the clinically acceptable values of 3.3 and 2.7 and those between ΔE00 and the clinically acceptable value of 1.8 were evaluated with one sample t-test (P<.05). Differences among the different shades were assessed through One-Way ANOVA and Bonferroni multiple comparison tests. RESULTS: Significantly lower values were detected for all groups concerning ΔEab compared to the intraorally clinical acceptable values of 3.3 and 2.7. Significantly lower mean values were detected for groups B3, C3, and D3, concerning ΔE00 compared to the intraorally clinical acceptant value of 1.8. Color pigments in red-brown (A3) and red-grey (D3) shades affect the total color change to a greater extent after the reinforcement with SiO2 nanoparticles compared to the red-yellow (B3) shade. CONCLUSION: Within the limitations of this in vitro study, it can be suggested that reinforcing PMMA with SiO2 nanoparticles at 0.25 wt% slightly affects the optical properties of the PMMA resin without being clinically perceivable.
In Vitro Techniques ; Nanoparticles ; Polymethyl Methacrylate ; Prostheses and Implants ; Silicon Dioxide

Bone and soft tissue conditions are important for successful implant treatment. But, the placement itself is also very important. Implants which is installed in the wrong position result in the biological, esthetical and mechanical problems. In order to place an implant in the correct position, the final restoration and diagnostic wax-up should be considered prior to the surgery. If the artificial teeth for the interim denture are directly transferred from the diagnostic wax-up, the operator can try the form of diagnostic wax-up in the mouth. If the surgical template is produced by duplicating the interim denture, the implant can be placed in the planned position. In this case, the polymethyl methacrylate (PMMA) artificial tooth was precisely milled by the digital duplication of diagnostic wax-up. And interim denture was fabricated by using these milled teeth. After the patient adapted for a sufficient period, the implant was placed at the planned position with surgical template produced by duplicating the interim denture. After confirming sufficient osseointegration, the final prostheses were made to reflect the shape of diagnostic wax-up. Through this procedure, the satisfactory functional and esthetic outcome could be acquired.
Dental Implants ; Dental Prosthesis ; Dentures ; Humans ; Mouth ; Osseointegration ; Polymethyl Methacrylate ; Prostheses and Implants ; Rehabilitation ; Tooth ; Tooth, Artificial

PURPOSE: To investigate the radiological efficacy of polymethylmethacrylate (PMMA) augmentation of pedicle screw operation in osteoporotic vertebral compression fractures (OVCF) patients. MATERIALS AND METHODS: Twenty OVCF patients, who underwent only posterior fusion using pedicle screws with PMMA augmentation, were included in the study. The mean follow-up period was 15.6 months. The demographic data, bone mineral density (BMD), fusion segments, number of pedicle screws, and amount of PMMA were reviewed as medical records. To analyze the radiological outcomes, the radiologic parameters were measured as the time serial follow-up (preoperation, immediately postoperation, postoperation 6 weeks, 3, 6 months, and 1 year follow-up). RESULTS: A total of 20 patients were examined (16 females [80.0%]; mean age, 69.1±8.9 years). The average BMD was −2.5±0.9 g/cm2. The average cement volume per vertebral body was 6.3 ml. The mean preoperative Cobb angle of focal kyphosis was 32.7°±7.0° and was improved significantly to 8.7°±6.9° postoperatively (p<0.001), with maintenance of the correction at the serial follow-up, postoperatively. The Cobb angle of instrumented kyphosis, wedge angle, and sagittal index showed similar patterns. In addition, the anterior part of fractured vertebral body height averaged 11.0±5.0 mm and was improved to 18.5±5.7 mm postoperatively (p=0.006), with maintenance of the improvement at the 3-month, 6-month, and 1-year follow-up. CONCLUSION: The reinforcement of pedicle screws using PMMA augmentation may be a feasible surgical technique for OVCF. Moreover, it appears to be appropriate for improving the focal thoracolumbar/lumbar kyphosis and is maintained well after surgery.
Body Height ; Bone Density ; Female ; Follow-Up Studies ; Fractures, Compression ; Humans ; Kyphosis ; Medical Records ; Osteoporosis ; Pedicle Screws ; Polymethyl Methacrylate