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Dental Materials Journal 2016Direct pulp-capping is a method for treating exposed vital pulp with dental material to facilitate the formation of reparative dentin and to maintain vital pulp. Two... (Review)
Review
Direct pulp-capping is a method for treating exposed vital pulp with dental material to facilitate the formation of reparative dentin and to maintain vital pulp. Two types of pulp-capping materials, calcium hydroxide and mineral trioxide aggregate, have been most commonly used in clinics, and an adhesive resin has been considered a promising capping material. However, until now, there has been no comprehensive review of these materials. Therefore, in this paper, the composition, working mechanisms and clinical outcome of these types of pulp-capping materials are reviewed.
Topics: Aluminum Compounds; Boron Compounds; Calcium Compounds; Calcium Hydroxide; Dental Cements; Dental Pulp Capping; Dental Pulp Exposure; Dentition, Permanent; Drug Combinations; Humans; Methylmethacrylates; Oxides; Resin Cements; Silicates
PubMed: 26830819
DOI: 10.4012/dmj.2015-013 -
IARC Monographs on the Evaluation of... 1994
Review
Topics: Animals; Carcinogenicity Tests; Carcinogens; Colorectal Neoplasms; Humans; Methylmethacrylate; Methylmethacrylates; Occupational Exposure
PubMed: 7869579
DOI: No ID Found -
Clinical and Applied... 2023Since Charnley introduced acrylic cement to seal metallic hip prostheses in the 1950s, reports of perioperative fatal cardiorespiratory and vascular dysfunctions have... (Review)
Review
Since Charnley introduced acrylic cement to seal metallic hip prostheses in the 1950s, reports of perioperative fatal cardiorespiratory and vascular dysfunctions have been published. Studies on humans and animals have shown neurogenic stimulation and substantial local and systemic activation of coagulation are caused by surgical bone marrow damage and chemical cell destruction by toxic monomeric methyl methacrylate from the implanted cement and other tissue-released substances. Venous blood-borne cell fragments and conjugates of activated cells from the surgical site are sequestered and trapped in the pulmonary microcirculation. A substantial hypercoagulation occurs in the lung circulation. Hypercoagulable blood is passed over to the arterial side and may cause vessel obliteration and organ damage. This process may affect the brain, heart, and kidneys and, through the release of vasoactive substances, introduce hemodynamic imbalances that can lead to fatal outcomes in susceptible populations such as elderly patients with hip fractures. The main underlying pathophysiologic processes leading to these occasionally devastating outcomes are a substantial activation of coagulation and cell destruction caused by the toxic substance released by curing bone cement and several vasoactive substances.
Topics: Animals; Humans; Aged; Bone Cements; Blood Coagulation; Hip Prosthesis; Methylmethacrylate
PubMed: 37792504
DOI: 10.1177/10760296231198036 -
Advances in Clinical and Experimental... Jul 2017Tissue conditioners (TCs) are short-term soft liners, formed in situ from a mixture of a polymer powder and a liquid plasticizer. This article reviews the recent... (Review)
Review
Tissue conditioners (TCs) are short-term soft liners, formed in situ from a mixture of a polymer powder and a liquid plasticizer. This article reviews the recent advances in the composition, functions, clinical use, gelation process, and physical properties of TCs and their effects on denture bases and oral mucosa. TCs are used to improve the fit and function of an ill-fitting denture. They can also be used to treat abused mucosal tissues underlying ill-fitting acrylic dentures as temporary expedients. TCs are recommended as provisional liners to maintain the fit of removable dentures and to prevent mechanical irritation from the denture. TCs may also be used to rehabilitate cancer patients. The polymer powder, used in the formulation of TCs generally consists of polyethyl methacrylate (PEMA) and the liquid plasticizer is ester-based in ethyl alcohol solution without an acrylic monomer. The plasticizers are low molecular weight aromatic esters. Mixing of the powder and liquid results in polymer chain entanglement and the formation of a coherent gel characterized by viscoelastic behavior appropriate to its intended clinical use. The loss of surface integrity and surface roughness of TCs are regarded as the main problems in the denture bearing oral mucosa conditions resulting in inflammation of oral mucosa of the denture-bearing area - denture stomatitis. TCs provide an even distribution of masticatory force, accurately modeling itself to the changes which occur during the healing of lesion of substrate and can act therapeutically by incorporating antifungal or antibacterial agents.
Topics: Denture Bases; Denture Liners; Humans; Methylmethacrylates; Plasticizers
PubMed: 28691420
DOI: 10.17219/acem/62634 -
BMC Musculoskeletal Disorders Oct 2022Antibiotic-loaded bone cement beads and spacers have been widely used for orthopaedic infection. Poor antibiotic elution is not capable of eradicating microbial...
OBJECTIVE
Antibiotic-loaded bone cement beads and spacers have been widely used for orthopaedic infection. Poor antibiotic elution is not capable of eradicating microbial pathogens and could lead to treatment failure. The elution profiles differ among different cement formulations. Although Simplex P cement has the least release amount, it is widely used due to its ready availability. Previous methods aiming to improve the elution profiles were not translated well to clinical practice. We sought to address this by using easily available materials to improve the elution profile of antibiotics from PMMA, which allows clinicians to implement the method intraoperatively.
METHODS
Vancomycin was mixed with Simplex P cement. We used Vicryl Rapide sutures to fabricate sustained-release cement beads by repetitively passing the sutures through the beads and/or mixing suture segments into the cement formulation. Vancomycin elution was measured for 49 days. The mechanism of antibiotic release was observed with gross appearance and scanning electron microscopic images. The antimicrobial activities against MRSA were tested using an agar disk diffusion bioassay.
RESULTS
Passing Vicryl Rapide sutures through cement beads significantly improved the elution profiles in the 7-week period. The increased ratios were 9.0% on the first day and 118.0% from the 2nd day to the 49th day. Addition of suture segments did not increase release amount. The Vicryl Rapide sutures completely degraded at the periphery and partially degraded at the center. The antibiotic particles were released around the suture, while antibiotic particles kept densely entrapped in the control group. The antimicrobial activities were stronger in passing suture groups.
CONCLUSION
Passing fast absorbable sutures through PMMA cement is a feasible method to fabricate sustained-release antibiotic bone cement. Intra-cement tunnels can be formed, and the effect can last for at least 7 weeks. It is suitable for a temporary spacer between two stages of a revision surgery.
Topics: Agar; Anti-Bacterial Agents; Bone Cements; Delayed-Action Preparations; Humans; Methylmethacrylate; Polyglactin 910; Polymethyl Methacrylate; Sutures; Vancomycin
PubMed: 36242041
DOI: 10.1186/s12891-022-05870-0 -
Journal of Oral Science 2022This study compared the bond strengths of four adhesive systems and four different resin composite block materials: Gradia Block (GR), Shofu Block HC (SH), Estelite...
PURPOSE
This study compared the bond strengths of four adhesive systems and four different resin composite block materials: Gradia Block (GR), Shofu Block HC (SH), Estelite Block (ES), and KZR-CAD HR2 (KZ).
METHODS
A primer (PZ-AB) containing a silane (γ-MPTS) with 10-methacryloyloxydecyl dihydrogen phosphate (MDP) was applied to ground surfaces of the resin composite block specimens, and the specimens were then bonded to stainless-steel rods using two methyl methacrylate-tributylborane (MMA-TBB)-based luting agents (SB and MT), designated as the PZ-AB/SB and PZ-AB/MT adhesive systems, respectively. The SB resin contained 4-methacryloyloxyethyl trimellitate anhydride (4-META), whereas the MT resin did not. The SB resin without primer (No primer/SB) and a dual-curing composite-type adhesive system (UPA/RelyX) were used as controls. The 24-h tensile bond strengths were determined and analyzed using the Tukey-Kramer HSD test (α = 0.05, n = 8).
RESULTS
The highest bond strengths were obtained for the GR/PZ-AB/MT, GR/PZ-AB/SB, KZ/PZ-AB/MT, ES/PZ-AB/SB, and KZ/No primer/SB groups, whereas the KZ/UPA/RelyX, ES/UPA/RelyX, SH/UPA/RelyX, and SH/No primer/SB groups exhibited the lowest bond strengths.
CONCLUSION
For each resin composite block material primed with γ-MPTS and MDP, the MMA-TBB-based luting agents, irrespective of the presence of 4-META, provided higher bond strengths than the dual-curing composite-type adhesive system.
Topics: Boron Compounds; Dental Bonding; Dental Cements; Materials Testing; Methacrylates; Methylmethacrylate; Phosphates; Silanes
PubMed: 35370182
DOI: 10.2334/josnusd.21-0513 -
Critical Reviews in Toxicology Mar 2011Methyl methacrylate (MMA) is a respiratory irritant and dermal sensitizer that has been associated with occupational asthma in a small number of case reports. Those... (Review)
Review
Methyl methacrylate (MMA) is a respiratory irritant and dermal sensitizer that has been associated with occupational asthma in a small number of case reports. Those reports have raised concern that it might be a respiratory sensitizer. To better understand that possibility, we reviewed the in silico, in chemico, in vitro, and in vivo toxicology literature, and also epidemiologic and occupational medicine reports related to the respiratory effects of MMA. Numerous in silico and in chemico studies indicate that MMA is unlikely to be a respiratory sensitizer. The few in vitro studies suggest that MMA has generally weak effects. In vivo studies have documented contact skin sensitization, nonspecific cytotoxicity, and weakly positive responses on local lymph node assay; guinea pig and mouse inhalation sensitization tests have not been performed. Cohort and cross-sectional worker studies reported irritation of eyes, nose, and upper respiratory tract associated with short-term peaks exposures, but little evidence for respiratory sensitization or asthma. Nineteen case reports described asthma, laryngitis, or hypersensitivity pneumonitis in MMA-exposed workers; however, exposures were either not well described or involved mixtures containing more reactive respiratory sensitizers and irritants. The weight of evidence, both experimental and observational, argues that MMA is not a respiratory sensitizer.
Topics: Air Pollutants, Occupational; Animals; Asthma; Computer Simulation; Disease Models, Animal; Humans; Hypersensitivity; Inhalation Exposure; Irritants; Laryngitis; Methylmethacrylates; Occupational Diseases; Occupational Exposure; Respiratory Mucosa; Structure-Activity Relationship
PubMed: 21401327
DOI: 10.3109/10408444.2010.532768 -
International Journal of Molecular... Mar 2020Poly(methyl methacrylate) (PMMA)-based bone cement, which is widely used to affix orthopedic metallic implants, is considered bio-tolerant but lacks osteoconductivity...
Poly(methyl methacrylate) (PMMA)-based bone cement, which is widely used to affix orthopedic metallic implants, is considered bio-tolerant but lacks osteoconductivity and is cytotoxic. Implant loosening and toxic complications are significant and recognized problems. Here we devised two strategies to improve PMMA-based bone cement: (1) adding 4-methacryloyloxylethyl trimellitate anhydride (4-META) to MMA monomer to render it hydrophilic; and (2) using tri-n-butyl borane (TBB) as a polymerization initiator instead of benzoyl peroxide (BPO) to reduce free radical production. Rat bone marrow-derived osteoblasts were cultured on PMMA-BPO, common bone cement ingredients, and 4-META/MMA-TBB, newly formulated ingredients. After 24 h of incubation, more cells survived on 4-META/MMA-TBB than on PMMA-BPO. The mineralized area was 20-times greater on 4-META/MMA-TBB than PMMA-BPO at the later culture stage and was accompanied by upregulated osteogenic gene expression. The strength of bone-to-cement integration in rat femurs was 4- and 7-times greater for 4-META/MMA-TBB than PMMA-BPO during early- and late-stage healing, respectively. MicroCT and histomorphometric analyses revealed contact osteogenesis exclusively around 4-META/MMA-TBB, with minimal soft tissue interposition. Hydrophilicity of 4-META/MMA-TBB was sustained for 24 h, particularly under wet conditions, whereas PMMA-BPO was hydrophobic immediately after mixing and was unaffected by time or condition. Electron spin resonance (ESR) spectroscopy revealed that the free radical production for 4-META/MMA-TBB was 1/10 to 1/20 that of PMMA-BPO within 24 h, and the substantial difference persisted for at least 10 days. The compromised ability of PMMA-BPO in recruiting cells was substantially alleviated by adding free radical-scavenging amino-acid N-acetyl cysteine (NAC) into the material, whereas adding NAC did not affect the ability of 4-META/MMA-TBB. These results suggest that 4-META/MMA-TBB shows significantly reduced cytotoxicity compared to PMMA-BPO and induces osteoconductivity due to uniquely created hydrophilic and radical-free interface. Further pre-clinical and clinical validations are warranted.
Topics: Animals; Arthroplasty, Replacement, Hip; Biocompatible Materials; Bone Cements; Bone Marrow Cells; Bone Regeneration; Bone and Bones; Boranes; Boron Compounds; Calcification, Physiologic; Cell Line; Cell Survival; Free Radicals; Hydrophobic and Hydrophilic Interactions; Male; Materials Testing; Methacrylates; Methylmethacrylate; Methylmethacrylates; Osteoblasts; Osteogenesis; Phenotype; Polymerization; Polymethyl Methacrylate; Prostheses and Implants; Rats; Rats, Sprague-Dawley
PubMed: 32244335
DOI: 10.3390/ijms21072405 -
Molecules (Basel, Switzerland) May 2020In nanoimprint lithography (NIL), a pattern is created by mechanical deformation of an imprint resist via embossing with a stamp, where the adhesion behavior during the...
In nanoimprint lithography (NIL), a pattern is created by mechanical deformation of an imprint resist via embossing with a stamp, where the adhesion behavior during the filling of the imprint stamp and its subsequent detachment may impose some practical challenges. Here we explored thermal and reverse NIL patterning of polyvinylferrocene and vinylferrocene-methyl methacrylate copolymers to prepare complex non-spherical objects and patterns. While neat polyvinylferrocene was found to be unsuitable for NIL, freshly-prepared vinylferrocene-methyl methacrylate copolymers, for which identity and purity were established, have been structured into 3D-micro/nano-patterns using NIL. The cross-, square-, and circle-shaped columnar structures form a 3 × 3 mm arrangement with periodicity of 3 µm, 1 µm, 542 nm, and 506 nm. According to our findings, vinylferrocene-methyl methacrylate copolymers can be imprinted without further additives in NIL processes, which opens the way for redox-responsive 3D-nano/micro-objects and patterns via NIL to be explored in the future.
Topics: Ferrous Compounds; Methylmethacrylate; Molecular Imprinting; Nanocomposites; Polymers; Polyvinyls; Surface Properties; Vinyl Compounds
PubMed: 32456151
DOI: 10.3390/molecules25102438 -
Journal of Oral Science Sep 2012This study examines the cytotoxicity of Super-Bond C&B (SB-C&B), Super-Bond RC Sealer (SB-RC), MetaSEAL (Meta), and AH Plus Sealer (AH+). Freshly mixed and set materials...
This study examines the cytotoxicity of Super-Bond C&B (SB-C&B), Super-Bond RC Sealer (SB-RC), MetaSEAL (Meta), and AH Plus Sealer (AH+). Freshly mixed and set materials (100 mg) were prepared in vitro and placed in cell culture medium (1 mL) for the working time and for 6 h, respectively. L929 cells seeded into 96-well plates at 5,000 cells/well were incubated with the eluted medium (200 µL) for 24 h. Cells cultured with medium alone served as the control. Cytotoxicity was evaluated by MTS assay and analyzed with ANOVA. In the freshly mixed group, the average ± SD (%) for cell viability were 66.0 ± 13.6, 55.5 ± 15.6, 10.6 ± 0.7, and 8.9 ± 2.2 for SB-C&B, SB-RC, Meta, and AH+, respectively. In the set group, the average ± SD (%) for cell viability were 100 ± 21.9, 81.8 ± 38.5, 24.9 ± 7.9, and 23.6 ± 10.0 for SB-C&B, SB-RC, Meta, and AH+, respectively. SB-C&B and SB-RC are less cytotoxic than are Meta and AH+.
Topics: Analysis of Variance; Animals; Boron Compounds; Cell Survival; Cells, Cultured; Epoxy Resins; L Cells; Materials Testing; Methacrylates; Methylmethacrylates; Mice; Resin Cements; Root Canal Filling Materials
PubMed: 23047031
DOI: 10.2334/josnusd.54.213