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Orthopadie (Heidelberg, Germany) Dec 2023PMMA-based bone cements are used for anchoring artificial joints. The cements are offered as two-component systems. During mixing, a liquid paste is formed by... (Review)
Review
PMMA-based bone cements are used for anchoring artificial joints. The cements are offered as two-component systems. During mixing, a liquid paste is formed by free-radical polymerization, which completely hardens into a solid cement matrix as polymerization progresses with an increase in viscosity. Polymerization from MMA to PMMA is an exothermic process, energy is released in the form of heat. After fixation of the prosthesis and curing of the cement, the cement fills the space between the prosthesis and the bone. With the filler PMMA, a strong force-locking and interlocking mechanical bond is created. The essential properties of PMMA cements are dictated by the powder component. In vivo, the hard and brittle bone cements absorb body fluids and become more elastic and softer. The properties of various PMMA bone cements differ significantly, although the chemical acrylate base is identical.
Topics: Bone Cements; Polymethyl Methacrylate; Materials Testing; Hot Temperature; Prosthesis Implantation
PubMed: 37831091
DOI: 10.1007/s00132-023-04445-8 -
International Journal of Nanomedicine 2023The main objective of this systematic review was to evaluate the effect of coating with titanium dioxide nanoparticles (TiO nanoparticle) on the surface condition of... (Review)
Review
BACKGROUND
The main objective of this systematic review was to evaluate the effect of coating with titanium dioxide nanoparticles (TiO nanoparticle) on the surface condition of removable acrylic resin prosthetic base materials.
METHODS
Our review is registered in the PROSPERO database under the identification code CRD42023397170. Electronic database searches of PubMed, Scopus and Science Direct including studies from January 2009 to January 2023 were conducted and supplemented with manual searches. Research questions were generated in accordance with the PICO strategy. The modified Consolidated Standards of Reporting Trials (CONSORT) checklist was used to evaluate the quality of the selected studies.
RESULTS
Since the included studies were variable in design, a meta-analysis was not performed. The electronic searches retrieved 29 references that met the eligibility criteria, among which 5 studies matched the inclusion criteria for this review. Significant differences were detected between the TiO NP-coated and uncoated groups. The available data indicate that TiO NP coating elicits antimicrobial activity and improves the wear resistance of polymethylmethacrylate (PMMA) surfaces. Moreover, the nanoparticles provide high levels of glossiness and decelerate the process of color change of heat-cured acrylic resin, thus increasing the lifespan of dentures.
CONCLUSION
The collective results clearly indicate that TiO nanoparticle coating induces alterations in the surface properties of pure PMMA, enhancing the mechanical, physical and biological characteristics of the denture base material. Further studies are essential to identify the optimal thickness of coating and concentrations of nanoparticles for clinical applications.
Topics: Polymethyl Methacrylate; Denture Bases; Surface Properties; Acrylic Resins; Titanium; Materials Testing
PubMed: 38026530
DOI: 10.2147/IJN.S425702 -
Aesthetic Plastic Surgery Dec 2023Nowadays, aesthetic concerns have gained attention, especially by patients looking for a less invasive alternative to minor facial corrections. Polymethylmethacrylate...
Nowadays, aesthetic concerns have gained attention, especially by patients looking for a less invasive alternative to minor facial corrections. Polymethylmethacrylate (PMMA) is widely used as a soft tissue filler; the demand for this polymer has increased, and along with it, there are some reports of adverse reactions. Such adverse reactions stem from consequences of immune and inflammatory reactions to PMMA. Some animal models have been used to unravel the causes of these reactions, among other factors involving the management of PMMA. The aim of this study was to determine the immunogenic profile of PMMA implantation in different anatomical planes of mice, over up to 360 experimental days. In this study, BALB/c mice were divided into 30 groups for immune evaluation of the interaction between the organism and the polymer; 2% PMMA was implanted subcutaneously, 10% intramuscularly and 30% in periosteal juxtaposition and followed during five experimental days (7, 30, 90, 180 and 360 days after implantation-DAI). Pro- and anti-inflammatory cytokines (IL-2, IL-4, IL-6, IFN-gamma, TNF, IL-17A, IL-10 and TGF-beta) were quantified in all experimental days. There was no statistical difference between the groups analyzed considering the evaluated parameters. Therefore, at all implanted depths, PMMA behaved inertly in a murine model.No Level Assigned This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .
Topics: Humans; Mice; Animals; Polymethyl Methacrylate; Microspheres; Face; Inflammation
PubMed: 36607354
DOI: 10.1007/s00266-022-03243-5 -
European Urology Feb 2024Magnetic resonance imaging (MRI) has been suggested as a tool for guiding biopsy recommendations in prostate cancer (PC) screening.
BACKGROUND
Magnetic resonance imaging (MRI) has been suggested as a tool for guiding biopsy recommendations in prostate cancer (PC) screening.
OBJECTIVE
To determine the performance of multiparametric MRI (mpMRI) in young men at age 45 yr who participated in a PC screening trial (PROBASE) on the basis of baseline prostate-specific antigen (PSA).
DESIGN, SETTING, AND PARTICIPANTS
Participants with confirmed PSA ≥3 ng/ml were offered mpMRI followed by MRI/transrectal ultrasound fusion biopsy (FBx) with targeted and systematic cores. mpMRI scans from the first screening round for men randomised to an immediate PSA test in PROBASE were evaluated by local readers and then by two reference radiologists (experience >10 000 prostate MRI examinations) blinded to the histopathology. The PROBASE trial is registered as ISRCTN37591328 OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The local and reference Prostate Imaging-Data and Reporting System (PI-RADS) scores were compared, and the sensitivity, negative predictive value (NPV), and accuracy were calculated for both readings for different cutoffs (PI-RADS 3 vs 4).
RESULTS AND LIMITATIONS
Of 186 participants, 114 underwent mpMRI and FBx. PC was detected in 47 (41%), of whom 33 (29%) had clinically significant PC (csPC; International Society of Urological Pathology grade group ≥2). Interobserver reliability between local and reference PI-RADS scores was moderate (k = 0.41). At a cutoff of PI-RADS 4, reference reading showed better performance for csPC detection (sensitivity 79%, NPV 91%, accuracy of 85%) than local reading (sensitivity 55%, NPV 80%, accuracy 68%). Reference reading did not miss any PC cases for a cutoff of PI-RADS <3. If PI-RADS ≥4 were to be used as a biopsy cutoff, mpMRI would reduce negative biopsies by 68% and avoid detection of nonsignificant PC in 71% of cases.
CONCLUSIONS
Prostate MRI in a young screening population is difficult to read. The MRI accuracy of for csPC detection is highly dependent on reader experience, and double reading might be advisable. More data are needed before MRI is included in PC screening for men at age 45 yr.
PATIENT SUMMARY
Measurement of prostate specific antigen (PSA) is an effective screening test for early detection of prostate cancer (PC) and can reduce PC-specific deaths, but it can also lead to unnecessary biopsies and treatment. Magnetic resonance imaging (MRI) after a positive PSA test has been proposed as a way to reduce the number of biopsies, with biopsy only recommended for men with suspicious MRI findings. Our results indicate that MRI accuracy is moderate for men aged 45 years but can be increased by a second reading of the images by expert radiologists. For broad application of MRI in routine screening, double reading may be advisable.
Topics: Male; Humans; Middle Aged; Prostatic Neoplasms; Multiparametric Magnetic Resonance Imaging; Prostate-Specific Antigen; Magnetic Resonance Imaging; Early Detection of Cancer; Reproducibility of Results; Image-Guided Biopsy; Polymethyl Methacrylate
PubMed: 37863727
DOI: 10.1016/j.eururo.2023.09.027 -
International Journal of Pharmaceutics Dec 2023The treatment of bone infections still involves systemic or local antibiotic therapy in high doses for prolonged periods. Current research focuses on the application of... (Review)
Review
The treatment of bone infections still involves systemic or local antibiotic therapy in high doses for prolonged periods. Current research focuses on the application of different drug delivery systems to the bone, aiming at a targeted local administration that will decrease the number of drugs used and their toxicity, compared to the systemic route. The gold standard in clinical practice is currently poly(methyl methacrylate) (PMMA) cement. The main drawback of PMMA, however, is that it is non-biodegradable, requiring a second follow-up surgery to remove the implant. Biodegradable delivery systems, on the other hand, are easily resorbable within the organism, and less invasive alternative with better patient compliance. Among biodegradable materials, natural and synthetic polymers are being studied as local drug delivery systems due to their excellent biocompatibility, sustained effect, and antibiotic release with high penetrability to infected bone and soft tissue. In this review, we focus on biodegradable polymeric platforms, such as micro- and nanoparticles, scaffolds, and hydrogels, as well as multi-delivery systems for targeting antibiotics to the bone. Additionally, we discuss the reported drug release profiles that provide important information about the systems' functionality.
Topics: Humans; Anti-Bacterial Agents; Polymethyl Methacrylate; Drug Delivery Systems; Polymers; Osteomyelitis
PubMed: 37940080
DOI: 10.1016/j.ijpharm.2023.123584 -
Nanomedicine (London, England) May 2024To investigate whether medical devices coated with a synthesized nanocomposite of poly(methylmethacrylate-co-dimethyl acrylamide) (PMMDMA) and silver nanoparticles...
To investigate whether medical devices coated with a synthesized nanocomposite of poly(methylmethacrylate-co-dimethyl acrylamide) (PMMDMA) and silver nanoparticles (AgNPs) could improve their antibiofilm and antimicrobial activities. We also investigated the nanocomposite's safety. The nanocomposite was synthesized and characterized using analytical techniques. Medical devices coated with the nanocomposite were evaluated for bacterial adhesion and hemolytic activity . The nanocomposite formation was demonstrated with the incorporation of AgNPs into the polymer matrix. The nanocomposite proved to be nonhemolytic and significantly inhibited bacterial biofilm formation. The PMMDMA-AgNPs nanocomposite was more effective in preventing biofilm formation than PMMDMA alone and is a promising strategy for coating medical devices and reducing mortality due to hospital-acquired infections.
PubMed: 38722243
DOI: 10.1080/17435889.2024.2345044 -
Macromolecular Bioscience Apr 2024The occurrence of periprosthetic joint infections (PJI) after total joint replacement constitutes a great burden for the patients and the healthcare system....
The occurrence of periprosthetic joint infections (PJI) after total joint replacement constitutes a great burden for the patients and the healthcare system. Antibiotic-loaded polymethylmethacrylate (PMMA) bone cement is often used in temporary spacers during antibiotic treatment. PMMA is not a load-bearing solution and needs to be replaced by a functional implant. Elution from the ultrahigh molecular weight polyethylene (UHMWPE) bearing surface for drug delivery can combine functionality with the release of clinically relevant doses of antibiotics. In this study, the feasibility of incorporating a range of antibiotics into UHMWPE is investigated. Drug stability is assessed by thermo-gravimetric analysis and nuclear magnetic resonance spectroscopy. Drug-loaded UHMWPEs are prepared by compression molding, using eight antibiotics at different loading. The predicted intra-articular concentrations of drugs eluted from UHMWPE are above minimum inhibitory concentration for at least 3 weeks against Staphylococci, which are the major causative bacteria for PJI. The antibacterial efficacy is confirmed for samples covering 2% of a representative knee implant in vitro over 72 h, showing that a small fraction of the implant surface loaded with antibiotics may be sufficient against Staphylococci.
Topics: Humans; Anti-Bacterial Agents; Polymethyl Methacrylate; Molecular Weight; Prosthesis-Related Infections; Polyethylenes; Bone Cements
PubMed: 38095273
DOI: 10.1002/mabi.202300389 -
American Journal of Veterinary Research Dec 2023To determine setting and temperature properties of diluted polymethyl methacrylate (PMMA) bone cement in vitro to assess utility for vocal fold augmentation in horses.
OBJECTIVE
To determine setting and temperature properties of diluted polymethyl methacrylate (PMMA) bone cement in vitro to assess utility for vocal fold augmentation in horses.
SAMPLES
4 dilutions of PMMA equivalent to volumes of 15 mL, 20 mL, 25 mL, and 30 mL PMMA powder (PMMAp) in 10 mL solvent.
METHODS
For each volume PMMAp, setting times (tset), peak temperatures (Tmax), and times to peak temperature (tmax) were determined using a temperature data logger in a 4-mL volume of PMMA. Injectability was assessed in vitro by documenting the force required to inject 0.2 mL PMMA through an 18-gauge 3.5-inch spinal needle attached to a 6-mL syringe at 1-minute intervals. Working time (twork) was calculated from a linear regression of injectability.
RESULTS
Peak temperatures increased with increasing volume of PMMAp: 56 °C, 86 °C, 99 °C, and 101 °C. Times for tset, twork, and tmax were inversely proportional to PMMA concentrations, resulting in tset of 23, 21, 17, and 14 minutes; twork of 22.75, 12.25, 7, and 4 minutes; and tmax of 28, 24, 19, and 16 minutes, respectively, for 15, 20, 25, and 30 mL PMMAp. Pairwise comparisons for all analyses were significant apart from Tmax for 25 and 30 mL PMMAp (P = .96) and twork for 20 and 25 mL PMMAp (P = .06).
CLINICAL RELEVANCE
Decreasing the concentration of PMMA bone cement resulted in longer working times and setting times; however, peak temperatures did not differ between the 2 strongest concentrations. Further research is warranted to quantify diluted PMMA properties for in vivo use for vocal fold augmentation in horses.
Topics: Animals; Horses; Polymethyl Methacrylate; Bone Cements; Temperature; Injections
PubMed: 37739393
DOI: 10.2460/ajvr.23.05.0110 -
World Neurosurgery Aug 2023The purpose of this study was to determine whether percutaneous vertebroplasty (PVP) and balloon kyphoplasty (BK) have any mid-term to long-term effects on the...
The Influence of Percutaneous Vertebral Augmentation Techniques on Recompression in Patients with Osteoporotic Vertebral Compression Fractures. Percutaneous Vertebroplasty versus Balloon Kyphoplasty.
OBJECTIVE
The purpose of this study was to determine whether percutaneous vertebroplasty (PVP) and balloon kyphoplasty (BK) have any mid-term to long-term effects on the structural integrity of augmented vertebrae.
METHODS
According to our hospital records, 351 patients underwent BK and PVP as a result of osteoporotic vertebral compression fractures between 2010 and 2020. The demographic, surgical, and radiologic characteristics of the patients were analyzed retrospectively using the electronic hospital records and PACS (picture archiving and communication system). In our study, 55 patients who had a single level of PVP or BK filled with at least 6 mL og polymethylmethacrylate (PMMA) for T11-L5 levels and 3 mL of PMMA for T6-T10 levels via a bipedicular approach and who had only 1 vertebral fracture in a 10-year follow-up period were included in our study. The patients were divided into 2 groups: BK (n = 40) and PVP (n = 15). All measurements were performed on standing lateral radiographs from the postoperative first day and the last radiographs that were obtained during the follow-up. The anterior and posterior heights of the fractured vertebral body and local kyphosis angles were measured.
RESULTS
The mean follow-up time was 2.53 ± 1.78 years in the BK group and 3.07 ± 2.02 years in the PVP group. The decrease in the vertebral height and increasing kyphosis that develop from the early to late postoperative periods were found to be statistically significant in the BK group (P < 0.05). In the PVP group, vertebral height and kyphosis angle measurements did not differ significantly between the early and late postoperative periods. In addition, in terms of the percentage change, anterior parts of the vertebral bodies are more affected. However, the absolute difference for the measurement of the vertebral heights did not confirm this finding.
CONCLUSIONS
To our knowledge, our study is unique because it has the longest follow-up in the literature comparing BK and PVP in terms of recollapse of the augmented vertebrae. Our study shows that BK does not prevent height loss of the augmented vertebral bodies in the mid- to long term.
Topics: Humans; Kyphoplasty; Spinal Fractures; Fractures, Compression; Polymethyl Methacrylate; Retrospective Studies; Vertebroplasty; Kyphosis; Osteoporotic Fractures; Treatment Outcome; Bone Cements
PubMed: 37257650
DOI: 10.1016/j.wneu.2023.05.081 -
The Journal of Prosthetic Dentistry Nov 2023Custom-made angled LOCATOR abutments have been used to compensate for the angulation of implants placed to support removable prostheses; however, their retention forces...
STATEMENT OF PROBLEM
Custom-made angled LOCATOR abutments have been used to compensate for the angulation of implants placed to support removable prostheses; however, their retention forces and the impact of mastication loading on retention have yet to be well addressed.
PURPOSE
The purpose of this in vitro study was to evaluate the retention force of custom-made LOCATOR abutments for implants placed at 0-, 15-, and 30-degree angulations with prefabricated abutments and to investigate the effect of mastication load on retention.
MATERIAL AND METHODS
Implant analogs were placed at the first molars of 40 maxillary typodonts, and 40 LOCATOR abutments were fabricated. Twenty implant analogs were placed at 0 degrees, 10 of which received prefabricated LOCATOR abutments and 10 of which received custom abutments. The remaining 20 implant analogs were placed at 15- and 30-degree angulations (n=10), and custom LOCATOR abutments were fabricated on them. A denture analog was digitally designed and manufactured from polymethyl methacrylate (PMMA) billets. Metal housings were then picked up using PMMA. The specimens were subjected to 2 rounds of 120 000 cycles of mastication loading. Retention force was assessed before and after each round of mastication loading using a universal testing machine. The wear of nylon inserts before and after mastication loading was accessed with a digital stereomicroscope. A 2-way ANOVA followed by the Tukey HSD test was used to determine the impacts of LOCATOR abutment type and times of mastication loading on the retention forces of the denture base (α=.05).
RESULTS
No significant difference in retention forces was found between prefabricated LOCATOR and custom abutments (placed at 0-, 15-, and 30-degree angulations) regardless of mastication loading (P>.05). The retentive force values of all groups increased significantly after the first round of mastication loading and decreased significantly to the initial level after the second round of mastication loading (P<.05).
CONCLUSIONS
Mastication loading impacted the retention force of both prefabricated and custom LOCATOR abutments; however, no significant difference in retention forces was found among various types of abutments.
Topics: Dental Implants; Denture Retention; Mastication; Polymethyl Methacrylate; Dental Prosthesis, Implant-Supported; Denture, Overlay; Dental Stress Analysis; Dental Abutments
PubMed: 37953027
DOI: 10.1016/j.prosdent.2023.07.033