Effect of elastomeric urethane monomer on physicochemical properties and shrinkage stress of resin composites

Abstract This study aimed to evaluate the effect of an elastomeric urethane monomer (Exothane-24) in different concentrations on physicochemical properties, gap formation, and polymerization shrinkage stress of experimental resin composites. All experimental composites were prepared with 50 wt.% of Bis-GMA and 50 wt.% of TEGDMA, to which 0 wt.% (control), 10 wt.%, 20 wt.%, 30 wt.%, and 40 wt.% of Exothane-24 were added. Filler particles (65 wt.%) were then added to these resin matrixes. Ultimate tensile strength (UTS: n = 10), flexural strength (FS: n = 10), flexural modulus (FM: n = 10), hardness (H: n = 10), hardness reduction (HR: n = 10), degree of conversion (DC: n = 5), gap width (GW: n = 10), and polymerization shrinkage stress in Class I (SS-I: n = 10) and Class II (SS-II: n = 10) simulated configuration. All test data were analyzed using one-way ANOVA and Tukey's test (α = 0.05; β= 0.2). Exothane-24 in all concentrations decreased the H, HR, DC, GW, SS-I, and SS-II (p < 0.05) without affecting the UTS, and FS (p > 0.05). Reduction in FM was observed only in the Exothane 40% and 30% groups compared to the control (p < 0.05). Exothane-24 at concentrations 20% and 30% seems suitable since it reduced GW and polymerization SS without affecting the properties of the composite resins tested, except for H.

Resumo Este estudo teve como objetivo avaliar o efeito de um monômero elastomérico de uretano (Exothane-24) em diferentes concentrações em propriedades físico-químicas, formação de fenda e tensão de contração de polimerização de resinas compostas experimentais. Todos os compósitos experimentais foram preparados com 50% em peso de Bis-GMA e 50% em peso de TEGDMA, nos quais 0% (controle), 10%, 20%, 30% e 40% em peso de Exothane-24 foram adicionados. Partículas de carga (65% em peso) foram então adicionadas as matrizes resinosas. Resistência coesiva (RC: n = 10), resistência à flexão (RF: n = 10), módulo de flexão (MF: n = 10), dureza (D: n = 10), redução de dureza (RD: n = 10), grau de conversão (GC: n = 5), largura de fenda (LF: n = 10) e tensão de contração de polimerização em simulações de cavidades Classe I (TC-I: n = 10) e Classe II (TC-II: n = 10). Todos os dados do teste foram analisados usando one-way ANOVA e teste de Tukey (α = 0,05; β = 0,2). O Exothane-24 em todas as concentrações diminuiu a D, RD, GC, LF, TC-I e TC-II (p < 0,05) sem afetar o RC e RF (p > 0,05). A redução da MF foi observada apenas nos grupos Exothane 40% e 30% em relação ao controle (p < 0,05). O Exothane-24 nas concentrações de 20% e 30% pareceu ser adequado, pois reduziu LF e TC de polimerização sem afetar as propriedades das resinas compostas testadas, exceto para D.

4-Flanged intrascleral fixation of an intraocular lens through the dialing hole

The high prevalence of mature, hypermature, and traumatic cataracts in developing countries, combined with the limited availability of surgical resources and skill by anterior segment surgeons to manage the resultant aphakia, leaves the patient needlessly blind. Relying on posterior segment surgeons, expensive surgical setup, and appropriate lenses for aphakia management limits the number of patients receiving a secondary intraocular lens (IOL). Utilizing the well-acknowledged flanging technique and the readily available polymethyl methacrylate (PMMA) lenses with dialing holes in their optic, a hammock can be created through the dialing holes using a 7-0 polypropylene suture on a straight needle. This 4-flanged scleral fixation through the dialing hole of an IOL makes scleral fixation of PMMA lens possible by even anterior segment surgeons without requiring any specialized equipment or scleral fixated lens with eyelet. This technique was successfully performed in a series of 103 cases with no incidence of IOL decentration.

Invitro Comparative Analysis of the Flexural Strength of 4 Different Commercially Available Provisional Materials Used in Fixed Partial Dentures – An Original Research

Background: Provisional Prosthesis in fixed partial dentures are subjected to Flexure under stress. Selection of appropriate material for fabrication of Provisional is of utmost importance as the Provisional prosthesis has to remain in function till definitive prosthesis is delivered. Material & Methods: Bar type specimens of four different commercially available brands for provisional restorations fabricated according to ADA specification No. 27 and immersed in artificial saliva. The specimens were fractured under 3-point loading test. Results: The flexural strength ranged between 60 to 110 Mpa. BisGMA Auto polymerizing composite resin from Dentsply Caulk shows the highest flexural strength. Conclusion: Within the limitations of this study, the flexural strengths were material specific rather than category one. The BisGMA composite based resin shows significantly higher flexural strength over other materials

Percutaneous vertebroplasty by percutaneous bi-level bilateral puncture for treatment of type ⅡA acute symptomatic osteoporotic thoracolumbar fractures with dense bone bands / 中华创伤骨科杂志

Objective:To evaluate the efficacy of percutaneous vertebroplasty (PVP) by percutaneous bi-level bilateral puncture in the treatment of type ⅡA acute symptomatic osteoporotic thoracolumbar fracture (ASOTLF) with dense bone bands.Methods:From March 2017 to March 2018, 65 patients (65 vertebrae) with type ⅡA ASOTLF with dense bone bands were treated at Department of Orthopaedic Trauma, Qingdao Central Hospital. They were 25 males and 40 females, with an age of (71.6±8.4) years. The time from injury to operation was (3.5±0.7) d. They were divided into 2 groups according to different treatments. In the observation group of 31 cases (31 vertebrae), PVP was conducted by percutaneous bi-level bilateral puncture; in the control group of 34 cases (34 vertebrae), PVP was conducted by percutaneous single-level bilateral puncture. The 2 groups were compared in terms of operation time, volume of polymethyl methacrylate injected, incidence of bone cement leakage, incidence of vertebral refracture, diffusive distribution of bone cement in the vertebral body, and visual analogue scale (VAS) and Oswestry dysfunction index (ODI) at postoperative 1 day and 6 months.Results:There was no significant difference in the preoperative general data between the 2 groups, showing comparability ( P>0.05). Operations were completed uneventfully in all the 65 patients. All the 65 patients were followed up for (8.2±1.2) months. There was no significant difference between the 2 groups in operation time, incidence of bone cement leakage or incidence of vertebral refracture for each vertebral body injured ( P>0.05). The volume of polymethyl methacrylate injected [(6.64±0.93) mL] and the excellent and good rate of diffusive distribution of bone cement in the vertebral body [87.1% (27/31)] in the observation group were significantly larger than those in the control group [(4.36±0.79) mL and 64.7% (22/34)] ( P<0.05). The VAS scores at postoperative 1 day and 6 months [2 (1, 2) and 1 (1, 2)] and ODIs at postoperative 1 day and 6 months (23.7%±1.6% and 18.8%±1.4%) in the observation group were significantly lower than those in the control group [2 (2, 3) and 2 (2, 2); 26.9%±4.2% and 22.1%±3.3%] ( P<0.05). The VAS scores and ODIs at postoperative 1 day and 6 months in all patients were significantly lower than those before operation ( P<0.05). Compression symptoms of the spinal cord and nerve root were observed in none of the patients. Conclusion:In the treatment of type ⅡA ASOTLF with dense bone bands, PVP by percutaneous bi-level bilateral puncture is more effective than the traditional PVP by percutaneous single-level bilateral puncture, and will not increase bone cement leakage or vertebral refracture.

Evaluation of utilizing cement-in-cement technique for endoprosthetic revision surgeries around the knee / 中华骨科杂志

Objective:To investigate the clinical efficacy of cement-in-cement (CiC) technique for endoprosthetic revision surgeries of noninfectious causes around the knee.Methods:All of 128 patients who had received cement-in-cement technique for endoprosthetic revision from February 2002 to August 2020 including 71 males and 57 females, whose mean age was 33.5±15.4 years (range, 8-77 years). 128 patients included 73 cases of osteosarcoma, 38 cases of giant cell tumors, 8 cases of undifferentiated sarcoma, 4 cases of chondrosarcoma, 2 cases of Ewing sarcoma, 2 cases of fibrosarcoma and 1 case of synovial sarcoma, with 105 cases in distal femur and 23 cases in proximal tibia. The failure mode classification included 64 cases of aseptic loosening, 47 cases of structure failure and 17 cases of tumor progression. 16 out of the 19 endoprosthese failure after the first cement-in-cement procedure received a second cement-in-cement procedure. The survival of revised prostheses, duration of the operation, the amount of blood loss, epidemiological data, complications and limb function were enrolled and statistical analyzed.Results:The mean follow-up from CiC revision was 127±33 months (range, 6-326 months). There were 25 (19.5%) complications for the first CiC procedure and 19 (14.8%) of the 25 complications lead to the protheses failure including 5 (3.9%) structure failure, 6 (4.7%) aseptic loosening, 2 (1.6%) tumor recurrence and 6 (4.7%) infection. The other 6 cases included 5 poor superficial wound healing and 1 patellar ligament rupture. All were recovered after debridement and tendon repair. The cumulative survival rates of first CiC procedure were 85.0%, 76.6% and 70.7% at 5, 10 and 15 years, respectively. Limb salvage rate was 97.7%. Sixteen of the 19 cases received a second CiC revision. The mean operative time (206±51 min vs. 258±41 min, t=3.18, P=0.399), blood loss (596±217.99 ml vs. 621±245.84 ml, t=0.30, P=0.926) and the median MSTS 93 score (26.38±2.47 vs. 25.06±2.11, t=1.61, P=0.376) of the first and second CiC procedure for the 16 cases were similar. Conclusion:CiC technique is a repeatable, conservative and viable option for endoprosthetic revision surgeries of noninfectious causes around the knee, with acceptable prosthetic survival rate, complication rate and limb function.

Effect of different mechanical surface treatments on flexural strength of repaired denture base / Efecto de diferentes tratamientos superficiales mecánicos sobre la resistencia a la flexión de la base de la dentadura reparada

Aim: To assess the effect of different mechanical surface treatments on flexural strength of repaired denture base. Material and Methods: Sixty bar-shaped specimens of heat-polymerized acrylic resin were fabricated, and divided into six groups (n=10). All specimens, except the positive control group (group PC), were sectioned into halves to create a 1-mm clearance. A negative control group with no surface treatment (group NC) was also considered. Other groups underwent different surface treatments: group Laser; treated with erbium: yttrium-aluminum-garnet (Er:YAG) laser, group APA; airborne-particle abrasion (APA), group APA plus Laser; a combination of laser and APA, and group Bur; bur grinding. After measuring surface roughness (Ra) with a profilometer, all sectioned specimens were repaired by auto-polymerizing acrylic resin, and thermocycled afterward. Three-point bending test was performed by a universal testing machine. Data were statistically analyzed (α=0.05). Results: The mean surface roughness of all experimental groups were significantly higher than that of group NC (p<0.05). The mean flexural strength of all groups was significantly lower than that of group PC (p<0.05). Group B had significantly higher flexural strength than the other surface-treated groups (p<0.05). Group Laser had significantly higher flexural strength than groups APA (p=0.043) and APA plus Laser (p=0.023). No significant difference was found between groups APA and APA plus Laser (p=0.684). Conclusion: All surface treatments increased the surface roughness and flexural strength compared with the untreated group. The highest flexural strength was observed in specimens treated by bur grinding and then laser, however, it was still significantly lower than intact specimens.

Objetivo: Evaluar el efecto de diferentes tratamientos superficiales mecánicos sobre la resistencia a la flexión de la base de la prótesis reparada. Material y Métodos: Se fabricaron sesenta especímenes en forma de barra de resina acrílica termo-polimerizada y se dividieron en seis grupos (n=10). Todas las muestras, excepto el grupo de control positivo (grupo PC), se seccionaron en mitades para crear un espacio libre de 1 mm. También se consideró un grupo de control negativo sin tratamiento superficial (grupo NC). Otros grupos se sometieron a diferentes tratamientos superficiales: grupo Láser; tratados con láser de erbio: itrio-aluminio-granate (Er:YAG), grupo APA; abrasión por partículas en el aire (APA), grupo APA más láser; una combinación de láser y APA, y grupo Bur; molienda de fresas. Después de medir la rugosidad de la superficie (Ra) con un perfilómetro, todas las muestras seccionadas se repararon con resina acrílica de autopolimerización y se sometieron a termociclado. La prueba de flexión de tres puntos se realizó con una máquina de prueba universal. Los datos se analizaron estadísticamente (α=0,05). Resultados: La rugosidad superficial media de todos los grupos experimentales fue significativamente mayor que la del grupo NC (p<0,05). La resistencia media a la flexión de todos los grupos fue significativamente menor que la del grupo PC (p<0,05). El grupo B tenía una resistencia a la flexión significativamente mayor que los otros grupos tratados en la superficie (p<0,05). El grupo Láser tuvo una resistencia a la flexión significativamente mayor que los grupos APA (p=0,043) y APA más Láser (p=0,023). No se encontró diferencia significativa entre los grupos APA y APA más Láser (p=0,684). Conclusión: Todos los tratamientos superficiales aumentan la rugosidad de la superficie y la resistencia a la flexión en comparación con el grupo sin tratar. La resistencia a la flexión más alta se observó en las muestras tratadas con fresado y luego con láser; sin embargo, aún era significativamente más baja que las muestras intactas.

Craneoplastía con prótesis de polimetilmetacrilato y planificación en 3D. Presentación de caso clínico y revisión de la literatura / Cranioplasty with polymethylmethacrylate prosthesis and 3D planification, case report and literature review

En este artículo se muestra que es posible realizar una prótesis digital con polimetilmetacrilato (PMMA) de forma sencilla con programas gratuitos y una impresora 3D de bajo costo y de fácil manejo. El caso clínico corresponde a un masculino de 38 años de edad quien refiere haber sido operado de urgencia por un hematoma subdural de origen traumático, secundario a una caída desde un andamio de 5 metros de altura, por parte del Servicio de Neurocirugía con una craneotomía descompresiva 10 meses atrás, actualmente presentando un defecto en región supraorbitaria y frontal bilateral y refiriendo cefaleas y mareos constantes con diagnóstico de síndrome del trefinado. Se decide diseñar digitalmente una prótesis con PMMA colocándola bajo anestesia general balanceada en quirófano mediante un acceso coronal, fijándola con tornillos de titanio y reposicionando tejidos con suturas. Se logra eliminar de forma inmediata el defecto visual, la sintomatología desapareció por completo confirmándolo en los controles desde los 7 días. Se muestra que es posible realizar una prótesis craneal personalizada de bajo costo de forma sencilla, resolviendo las molestias y eliminando las secuelas y complicaciones que afectan a los pacientes tratados por craniectomías descompresivas con presencias de defectos.

In this aticle it is showns that it is possible to make a digital prosthesis with Polymethylmethacrylate (PMMA) with free programs and a low-cost and easy-to-use 3D printer. The clinical case corresponds to a 38-year-old male who reported having undergone emergency surgery for a subdural hematoma of traumatic origin, secondary to a fall from a 5-meter-high scaffolding, procedure done by the Neurosurgery Service with a decompressive craniotomy 10 months ago, nowadays he presents a bilateral defect at the supraorbital and frontal region, referring constant headaches and dizziness with a diagnosis of a trephination syndrome. We decided to digitally design a prosthesis with PMMA, placing it under balanced general anesthesia in the operating room through a coronal approach, fixing it with titanium screws and repositioning tissues with sutures. The visual defect was immediately eliminated, the symptoms disappeared completely, confirming it at the controls since day 7. It is shown that it is possible to perform a low-cost personalized cranial prosthesis in a simple way, solving the discomfort and eliminating the sequelae and complications that affect patients treated by decompressive craniectomies with the presence of defects.

Sarcoidose cutânea e preenchimento facial: um possível evento desencadeante? / Cutaneous sarcoidosis and facial filling: a possible triggering event?

A sarcoidose é uma doença granulomatosa sistêmica com envolvimento cutâneo em 10 a 25% dos casos. O quadro cutâneo tem sido frequentemente associado a traumas prévios, incluindo o uso de preenchedores cutâneos. Apresenta-se caso de paciente com placa eritematosa em dorso nasal com 12 meses de evolução e histórico de preenchimentos prévios com PMMA e ácido hialurônico. A biópsia cutânea evidenciou processo inflamatório granulomatoso de padrão epitelióide e células gigantes multinucleadas, características de sarcoidose cutânea. As reações granulomatosas tardias podem estar associadas ao uso de preenchedores, tanto pelo trauma provocado pelas cânulas quanto pelos antígenos dos preenchedores utilizados

Sarcoidosis is a systemic granulomatous disease with skin involvement in 10% to 25% of cases. This skin condition has been associated with previous trauma, including the use of skin fillers. We present the case of a patient with an erythematous plaque on the nasal dorsum with 12 months of evolution and a history of previous facial fillings with polymethylmethacrylate and hyaluronic acid. Skin biopsy showed a granulomatous inflammatory process with an epithelioid pattern and multinucleated giant cells, characteristic of cutaneous sarcoidosis. Sarcoidosis can occasionally manifest without systemic involvement and may be associated with the previous use of long-term tissue fillers

Comparison of curative effects between percutaneous curved vertebroplasty and unilateral percutaneous kyphoplasty in the treatment of osteoporotic thoracolumbar compression fracture / 中华创伤杂志

Objective:To compare the clinical effects of percutaneous curved vertebroplasty (PCVP) and unilateral percutaneous kyphoplasty (PKP) in the treatment of osteoporotic vertebral compression fracture (OVCF).Methods:A retrospective cohort study was used to analyze the clinical data of 104 patients with single vertebral OVCF treated in Tianjin Hospital from September 2019 to September 2020, including 21 males and 83 females; aged 50-91 years [(70.3±7.7)years]. AO classification of the fracture was type A1 in 65 patients and type A2 in 39. The patients received PCVP (PCVP group, n=51) or unilateral PKP surgery (unilateral PKP group, n=53). The operation time, bone cement injection volume, intraoperative fluoroscopy frequency, effective dispersion times of bone cement and excellent rate of bone cement distribution were compared between the two groups. In evaluation of the therapeutic effects of the two groups, visual analogue scale (VAS) and Oswestry dysfunction index (ODI) were measured preoperatively and at postoperative 24 hours, 3 months and 6 months; Beck index was measured preoperatively and at postoperative 24 hours and 3 months. The rate of bone cement leakage and rate of refracture of adjacent vertebral bodies were compared between the two groups. Results:All patients were followed up for 6-8 months [(6.4±0.7)months]. The operation time, bone cement injection volume and intraoperative fluoroscopy frequency in PCVP group was (12.15±1.63)minutes, (2.13±0.28)ml and (24.74±1.71)times, shorter or less than (22.09±1.62)minutes, (5.30±0.52)ml and (30.09±1.86)times in unilateral PKP group (all P<0.01). The effective dispersion times of bone cement in PCVP group was (1.42±0.04)times, higher than (1.18±0.02)times in unilateral PKP group ( P<0.01). The excellent rate of bone cement distribution in PCVP group was 94%, higher than 70% in unilateral PKP group ( P<0.01). There were no significant differences in VAS, ODI and Beck index between the two groups before operation and at 24 hours and 3 months after operation (all P>0.05). VAS and ODI in PCVP group were (1.20±0.49)points and 16.52±5.22 at 6 months after operation, lower than (1.49±0.58)points and 20.16±5.16 in unilateral PKP group (all P<0.01). VAS and ODI in the two groups were significantly improved at 24 hours, 3 months and 6 months after operation when compared with those before operation (all P<0.05). Beck index in the two groups detected at 24 hours and 3 months after operation was improved from that before operation (all P<0.05). Unilateral PKP group showed Beck index was 0.75±0.07 at 3 months after operation, significantly lower than 0.79±0.07 at 24 hours after operation ( P<0.05), but there was no significant change in PCVP group ( P>0.05). The leakage rate of bone cement in PCVP group was 16% (8/51), lower than 47% (25/53) in unilateral PKP group ( P<0.01). There was no significant difference in the incidence of refracture of adjacent vertebral bodies between the two groups during follow-up ( P>0.05). Conclusion:For OVCF, PCVP is superior to unilateral PKP in terms of operation time, amount of bone cement injection, intraoperative fluoroscopy frequency, dispersion effect of bone cement in vertebral body, pain, function improvement, maintenance of injured vertebral height and incidence of bone cement leakage.

Factors Affecting Sorption and Solubility of Denture Base Acrylic Materials: A Review

@#Heat-cured PMMA is one of the most frequently used materials in the manufacture of removable dentures. Heat-cured material used to fabricate dentures contain soluble elements, allowing the material to absorb and release substances. These factors all directly affect the longevity and performance of protheses fabricated from polymethyl methacrylate denture base material. Various procedures associated with fabrication of removable dentures from heat-cure denture base material are reported to significantly influence the sorption and solubility experienced by the prosthesis. A comprehensive search of peer-reviewed journals located within academic databases was conducted to identify relevant literature pertaining to sorption and solubility of denture base materials. Key aspects of each paper were captured in Microsoft® Excel® to record author/s, location, study design, sample size, methodology, results and conclusions. Mixing ratios and polymerisation cycles have been identified as variables that can negatively influence the rate of sorption and solubility of denture base materials during the fabrication process. Certain surface treatment procedures, as well as storing the denture in artificial saliva solution may reduce the levels of sorption and solubility experienced and optimise its lifespan. In this review we identify these factors and consider the detrimental effects of sorption and solubility on denture base acrylic materials.

Bone-filling mesh container plasty for spinal metastases with damaged posterior wall of vertebra / 中华骨科杂志

Objective:To study the efficacy and safety of bone-filling mesh container plasty in the treatment of posterior wall fracture of vertebra caused by spinal metastases.Methods:This study is a retrospective analysis of 65 patients with pathological fractures of the vertebra caused by vertebral metastases treated with bone-filling mesh container plasty from January 2015 to December 2019. There were 21 males and 44 females, 70.3±10.8 (46-90) (years). According to primary tumor, there were 25 cases of lung cancer, 14 cases of breast cancer, 11 cases of digestive system cancer, 13 cases of urinary system cancer, 1 case of lymphoma and 1 case of ovarian cancer. In the segment of vertebral metastases, there were 2 cases of T 2 vertebra, 1 case of T 5 vertebra, 1 case of T 6 vertebra, 2 cases of T 8 vertebra, 1 case of T 9 vertebra, 5 cases of T 10 vertebra, 4 cases of T 11 vertebra, 15 cases of T 12 vertebra, 12 cases of L 1 vertebra, 8 cases of L 2 vertebra, 8 cases of L 3 vertebra, 4 cases of L 4 vertebra, and 2 cases of L 5 vertebra. According to the CT images of the patient's vertebra before operation, the area of the damaged posterior wall of the vertebra is measured as s, and the area of the posterior wall of the intact vertebra is measured as S. The ratio of posterior wall damage is calculated as R= s/ S, and the value of R represents the degree of damage to the posterior wall of the vertebra. According to the size of the R value, the patients were divided into four groups, typeⅠ( R≤25%, 21 cases), typeⅡ(25%< R≤50%, 22 cases), typeⅢ (50%< R≤75%, 14 cases), typeⅣ( R>75%, 8 cases). The visual analog scale (VAS), Oswestry disability index (ODI) and activity of daily living (ADL) before and 1 day after surgery, 1 month after surgery, and 3 months after surgery were analyzed and compared to evaluate the efficacy of bone-filling mesh container plasty. Pairwise comparisons were performed to verify whether there is a difference in efficacy, bone cement leakage and postoperative complications. Results:All 65 patients were followed up for 3-6 months, with an average of 3.8 months. The VAS scores before surgery, postoperative day 1, postoperative 1, 3 months were 7.32±0.99, 4.14±1.06, 4.11±0.97, and 4.34±1.11, respectively, with a statistically significant difference ( F=149.20, P<0.001). ODI of preoperative, postoperative day 1, postoperative 1, and 3 months were 69.45%±4.15%, 36.65%±3.72%, 36.84%± 3.38%, 37.78%±3.45%, respectively, with a statistically significant difference ( F=840.88, P<0.001). ADL score of preoperative, postoperative day 1, postoperative 1, and 3 months were 71.31±12.81, 79.85±9.14, 78.92±8.95, and 78.31±8.67, respectively, with a statistically significant difference ( F=149.20, P<0.001). There was no significant difference in VAS, ODI and ADL scores between types I and IV (all P>0.05), but with the increase of R value, the leakage rate of intraspinal bone cement would increase correspondingly. Eleven cases occurred bone cement leakage with the rate of 17%. The leakage rate of type I and II was 0, type III was 7.1% (1/14), and type IV was 37.5% (3/8). All patients did not have systemic complications such as allergies, shock, decreased oxygen saturation, etc., and there were no bleeding, infection, nerve root symptoms or cement insertion syndrome after surgery. Conclusion:Bone-filling mesh container plasty can significantly improve the pain symptoms of patients with spinal metastases and recovery functions. The degree of damage to the posterior vertebra has no effect on the efficacy of the surgery. As the degree of damage to the posterior wall of the vertebra increases, the risk of complications of bone cement leakage in the spinal canal will increase.

Research progress on health hazards and occupational protection of prolymethylmethacrylate bone cement in the operating room / 中华劳动卫生职业病杂志

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.

Study on dynamic expression of IL-10 on scarring after implantation of glaucoma drainage material / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM:To investigate the dynamic expression characteristics of interleukin-10(IL-10)after implantation of glaucoma drainage material, and to reveal the role of IL-10 on scarring formation.METHODS:Totally 75 New Zealand white rabbits were randomly divided into three groups, which were implanted with different types of material-Polymethyl methacrylate coated Parylene C(PMMA group), silicone together with injection of Mitomycin C(MMC)(silicon-MMC group)and silicone(silicone group). Aqueous humor were collected at 1, 3d, 1, 2, 3, 4 and 8wk after operation and enzyme-linked immunosorbent assay(ELISA)were utilized to detect the expression of IL-10 in the aqueous humor. The connective tissue surrounding the material were collected at 1, 2, 3, 4 and 8wk postoperatively. Hematoxylin-eosin(HE)staining was applied to evaluate the proliferation of fibroblasts and the infiltration of inflammatory cells. The protein expression and mRNA of IL-10 in the connective tissue were detected by immunohistochemistry and real-time PCR.RESULTS:Compared with PMMA and silicon-MMC group, silicone group showed significantly increased proliferation of fibroblasts and infiltration of inflammatory cells according to the HE staining result. The result of ELISA showed the expression of IL-10 in the aqueous humor increased significantly at the early stage after surgery, and then decreased gradually,the highest appeared on the third day after operation,and in silicone group there was higher than the other two groups in the early stage postoperatively(1d-3wk)(all <i>P</i><0.05), and there was no significant difference in the late stages(4-8wk). The protein expression and mRNA of IL-10 in connective tissue were the highest in the first week after operation, decreased gradually at 2-3wk after operation, and increased again at 4-8wk after operation by immunohistochemistry and real-time PCR. And the expression was higher in silicone group than in the other two groups at each time point(all <i>P</i><0.05). Furthermore, there was a positive correlation between the expression of IL-10 protein and the proliferation of fibroblasts in the late stages(4-8wk).CONCLUSION: After implantation of glaucoma drainage material, the process of IL-10 increased first, then decreased gradually, and increased again 4wk later, thus IL-10 may be a potential target for inhibiting the scar formation.

Release of leachable products from resinous compounds in the saliva of children with anterior open bite treated with spur

Abstract To evaluate the release of bisphenol-A glycidyl methacrylate (BisGMA), triethylene glycol dimethacrylate (TEGDMA), bisphenol A (BPA), and phthalates of the composite resin used in the bonding of spurs applied in the treatment of children with anterior open bite and its effects on human keratinocytes. Methodology Saliva samples of 22 children were collected before spur attachment (baseline) and 30 minutes (min) and 24 hours (h) after spur bonding. Analysis was performed using high-performance liquid chromatography (HPLC) coupled to tandem mass spectrometry (HPLC-MS/MS) and gas chromatography coupled to mass spectrometry (GC-MS). Standardized resin increments were added to three different dilutions of the cell culture medium. Keratinocytes (HaCaT) were cultivated in the conditioned media and evaluated for cell viability (MTT) and cell scratch assay. Results The levels of BisGMA (1.74±0.27 μg/mL), TEGDMA (2.29±0.36 μg/mL), and BPA (3.264±0.88 μg/L) in the saliva after 30 min, in comparison to baseline (0±0 μg/mL, 0±0 μg/mL, and 1.15±0.21 μg/L, respectively), presented higher numbers. After 24 h, the levels of the monomers were similar to the baseline. Phthalates showed no significant difference among groups. HaCat cells showed increased viability and reduced cell migration over time after exposure to methacrylate-based resin composites. Conclusion Resin composites, used to attach spurs in children with anterior open bite during orthodontic treatment, release monomers after polymerization and can influence the behavior of human keratinocytes, even at very low concentrations. Orthodontists should be aware of the risks of the resinous compounds release and preventive procedures should be held to reduce patient exposure.

Antibiotic cement-coated plate is a viable and efficient technique for the definitive management of metaphyseal septic nonunions of the femur and tibia / O uso de placas revestidas de cimentado com antibiótico é uma técnica viável e eficiente para o tratamento da pseudoartrose infectada da metáfise do fêmur e da tíbia

ABSTRACT Objective: the management of septic metaphyseal nonunions is challenging, with inconsistent outcomes. Antibiotic cement-coated implants have been demonstrated good outcome for diaphyseal infected nonunions, however there is no data in metaphyseal infected nonunions. Methods: fifteen adult patients with septic metaphyseal nonunions of the femur or tibia were treated with antibiotic cement-coated plates. The antibiotic cement-coated plate was prepared with either gentamicin or vancomycin. Outcome measures were infection control, bone healing, return to pre-injury level on daily activities, and quality of life at the last follow-up visit. A p value of <5% was considered significant. Results: Methicillin-susceptible S. aureus was isolated in 53.3% cases. Average postoperative follow-up time was 18 months. Local infection control and radiographic bone healing were adequately achieved in 93.3% patients. No patient presented recurrent symptoms of surgical site infection. Fourteen patients reported to be either able, or on the same level as before injury, with 73.3% reporting no problems in all five dimensions of the EQ-5D-3L. Persistent infection was the only variable associated with a reduced long-term quality of life. Conclusion: antibiotic cement-coated plate is a viable and efficient surgical technique for the definitive management of juxta-articular metaphyseal septic nonunions of the femur and tibia.

RESUMO Introdução: implantes revestidos de cimento com antibiótico vêm demonstrando bons resultados no tratamento da pseudoartrose infectada da diáfise, no entanto seu uso na metáfise dos ossos longos ainda é pouco explorado. Neste estudo relatamos uma série de casos de pseudoartrose infectada da metáfise do fêmur e da tíbia tratados com o uso de placas revestidas de cimento com antibiótico. Métodos: Os antibióticos usados foram gentamicina e/ou vancomicina. Os desfechos analisados na última visita ambulatorial foram controle de infecção, consolidação óssea, retorno às atividades diárias e qualidade de vida. Regressão linear bivariada foi usada para avaliar fatores individuais que afetaram a qualidade de vida dos pacientes. Um valor p<5% foi considerado estatisticamente significativo. Resultados: quinze pacientes adultos foram incluídos no estudo. S. aureus suscetível à meticilina foi isolado em 53,3% dos casos. O tempo médio de acompanhamento pós-operatório foi de 18 meses. Controle local da infecção e consolidação óssea radiográfica foram alcançados em 93,3% dos pacientes. Nenhum paciente apresentou sintomas recorrentes de infecção de sítio cirúrgico. Quatorze pacientes relataram ser capazes, mas não no nível pré-lesional ou no mesmo nível de antes da lesão, com 73,3% relatando nenhum problema em todas as cinco dimensões do EQ-5D-3L. Infecção persistente foi a única variável associada à redução da qualidade de vida a longo prazo. Conclusão: A placa revestida de cimento com antibiótico mostrou-se uma técnica cirúrgica viável e eficiente para o tratamento da pseudoartrose infectada da metáfise do fêmur e da tíbia.

The effect of cooling procedures on monomer elution from heat-cured polymethyl methacrylate denture base materials

Abstract Objective To evaluate the amount of methyl methacrylate (MMA) released in water from heat-cured polymethyl methacrylate (PMMA) denture base materials subjected to different cooling procedures. Methodology Disk-shaped specimens (Ø:17 mm, h:2 mm) were fabricated from Paladon 65 (PA), ProBase Hot (PB), Stellon QC-20 (QC) and Vertex Rapid Simplified (VE) denture materials using five different cooling procedures (n=3/procedure): A) Bench-cooling for 10 min and then under running water for 15 min; B) Cooling in water-bath until room temperature; C) Cooling under running water for 15 min; D) Bench-cooling, and E) Bench-cooling for 30 min and under running water for 15 min. A, B, D, E procedures were proposed by the manufacturers, while the C was selected as the fastest one. Control specimens (n=3/material) were fabricated using a long polymerization cycle and bench-cooling. After deflasking, the specimens were ground, polished and stored in individual containers with 10 ml of distilled water for seven days (37oC). The amount of water-eluted MMA was measured per container using isocratic ultra-fast liquid chromatography (UFLC). Data were analyzed using Student's and Welch's t-test (α=0.05). Results MMA values below the lower quantification limit (LoQ=5.9 ppm) were registered in B, C, E (PA); E (PB) and B, D, E (QC) procedures, whereas values below the detection limit (LoD=1.96 ppm) were registered in A, D (PA); A, B, C, D (PB); C, D, E (VE) and in all specimens of the control group. A, B (VE) and A, C (QC) procedures yielded values ranging from 6.4 to 13.2 ppm with insignificant differences in material and procedure factors (p>0.05). Conclusions The cooling procedures may affect the monomer elution from denture base materials. The Ε procedure may be considered a universal cooling procedure compared to the ones proposed by the manufacturers, with the lowest residual monomer elution in water.

Polymeric Material With Controlled Release of Antimicrobial Agents for Medical Application

@#Introduction: Nowadays the use of synthetic polymers has become an integral part of modern medicine. Poly(2-hydroxyethyl methacrylate) has attracted special attention for therapeutic use. The objective of this study was to develop novel polymeric material based on poly(2-hydroxyethyl methacrylate) by addition of water as pore-forming agent and antimicrobial components, which would differ from similar materials by controlled release of active substances. Methods: The antimicrobial release kinetics study materials were immersed into distilled water followed by sampling and measuring their concentration. Concentration of chlorhexidine bigluconate and metronidazole was determined using spectrophotometric method and decamethoxine by photocolorimetric method based on reaction with eosin. The swelling rate was determined by gravimetric method. Results: Conventional dressing materials, after being soaked with antiseptic solutions, have demonstrated limited abilities in releasing active substances. Gauze pads were found to release antimicrobials during a short period of time reaching 50–80 % for decamethoxine containing samples and almost 100 % for those with metronidazole and chlorhexidine bigluconate at 2 h of observation. No study active substances were released from activated charcoal dressings. Similar results were obtained with porcine xenografts. Unlike the above mentioned dressing materials, modified polymer matrix based on poly(2-hydroxyethyl methacrylate) showed the controlled release of antimicrobial substances into water medium. Study material containing 3.0 % of decamethoxine and 76.3 % of water demonstrated optimal efficiency in the rate and duration of release, exerting high physical and mechanical properties. Conclusion: The synthesized polymers are similar to conventional dressings in antimicrobial release kinetics, but in some characteristics they are better for practical application.

Evaluation of Intramedullary Methods with Polymethylmethacrylate for Fixation of Bone Lesions of the Extremities / Avaliação de métodos intramedulares com polimetilmetacrilato para fixação em lesões ósseas de extremidades

Abstract Objective To evaluate the better potential and functional results in pain control in the treatment of pathological fractures and prophylactic fixation with an intramedullary nail associated with polymethylmethacrylate, compared with the utilization of an intramedullary nail in long bone tumor lesions. Methods From January 2012 to September 2017, 38 patients with 42 pathological lesions (fractures or impending fractures according to the Mirels criteria) were treated surgically. Sixteen patients allocated to the control group underwent a locked intramedullary nail fixation, and 22 patients with pathological lesions were allocated to treatment with an intramedullary nail associated with polymethylmethacrylate. Postoperatively, the patients were submitted to the Musculoskeletal Tumor Society (MSTS) rating scale, radiographic assessment, and to the assessment of events and complications related to the treatment. Results The evaluation using the MSTS questionnaire showed better functional results in the group associated with polymethylmethacrylate, in comparison with the control group, which obtained an average score of 16.375 out of a maximum of 30 points (54.6%). The group studied with association with polymethylmethacrylate obtained a mean of 22.36 points (74.5%). The procedure proved to be safe, with similar complication and severity rates, and with no statistical difference in comparison with the standard treatment. Conclusion Stabilization of tumor lesions with an internal fixation associated with the polymethylmethacrylate demonstrated early rehabilitation and improved the quality of life, allowing rapid functional recovery. The use of polymethylmethacrylate has advantages such as reduced bleeding, tumor necrosis and higher mechanical stability.

Resumo Objetivo Avaliar o potencial melhor resultado funcional e controle álgico no tratamento de fraturas patológicas e fixações profiláticas tratadas com haste intramedular associada ao polimetilmetacrilato (PMMA) em comparação com o uso de haste intramedular em lesões tumorais em ossos longos. Métodos De janeiro de 2012 a setembro de 2017, 38 pacientes com 42 lesões patológicas (fraturas ou iminência segundo os critérios de Mirels) foram tratados cirurgicamente. Dezesseis pacientes submetidos a fixação com haste intramedular bloqueada foram alocados ao grupo controle e 22 pacientes com lesões patológicas foram alocados para tratamento com haste intramedular associada ao PMMA. No pósoperatório, foi realizada a submissão dos pacientes ao escore da Musculoskeletal Tumor Society (MSTS, na sigla em inglês) e à avaliação radiográfica do tratamento realizado, assim como à avaliação de intercorrências e complicações relacionadas ao tratamento. Resultados A avaliação através do questionário MSTS demonstrou melhor resultado funcional do grupo associado com PMMA quando comparado com o grupo controle, o qual obteve uma pontuação média de 16,375 em um máximo de 30 pontos (54,6%), enquanto o grupo em estudo com associação do PMMA obteve uma média de 22,36 pontos (74,5%). O procedimento mostrou-se seguro, taxas de complicações e gravidade semelhantes e sem diferença estatística quando comparado com o tratamento padrão. Conclusão A estabilização de lesões tumorais com fixação associada ao PMMA demonstrou reabilitação precoce e melhora na qualidade de vida, permitindo rápida recuperação funcional. A utilização do PMMA apresenta vantagens como diminuição do sangramento e da necrose tumoral e maior estabilidade mecânica.

Reação de corpo estranho após reconstrução órbito-zigomático-maxilar com polimetilmetacrilato: relato de caso / Strange body reaction after orbit-zygomatic-maxillary reconstruction with polymethyl methacrylate: case report

Pacientes com históricos de defeitos ósseos provocados por infecções, malformação congênita, neoplasias, deformação por iatrogenia, radioterapia e trauma buscam contornos faciais mais harmônicos através da reabilitação cirúrgica. Para facilitar a reconstrução maxilofacial dois grupos de materiais podem ser utilizados, os enxertos ósseos e os materiais aloplásticos. O objetivo é relatar um caso incomum de infecção e exposição de material utilizado para enxertia a base de polimetilmetacrilato, bem como a sua posterior reabordagem cirúrgica. Embora o Polimetilmetacrilato aparente ser seguro, ele exibe complicações diversas em função da imunologia do hospedeiro, que poderá reagir de diferentes formas. Desse modo, faz-se necessário ressaltar a importância da prevenção e proservação de cada caso de forma individualizada(AU)

Patients with a history of bone defects caused by infections, congenital malformation, neoplasms, iatrogenic deformation, radiotherapy and trauma seek more harmonious facial contours through surgical rehabilitation. To facilitate maxillofacial reconstruction, two groups of materials can be used, bone grafts and alloplastic materials. The objective is to report an unusual case of infection and exposure of material used for grafting with polymethylmethacrylate, as well as its subsequent surgical approach. Although Polymethylmethacrylate appears to be safe, it exhibits different complications depending on the host's immunology, which may react in different ways. Thus, it is necessary to emphasize the importance of preventing and preserving each case individually(AU)

Case reports of hypercalcemia and chronic renal disease due to cosmetic injections of polymethylmethacrylate (PMMA) / Relatos de casos de hipercalcemia e doença renal crônica devidas a injeções de polimetilmetacrilato (PMMA) por razões estéticas

Abstract Cosmetic injections of fillers are common plastic surgery procedures worldwide. Polymethylmethacrylate (PMMA) is a filler approved only for minimally invasive procedures in facial tissue and is among the most frequently used injectable substances for cosmetic purposes. Injection of a large volume of PMMA may lead to the development of severe hypercalcemia and chronic kidney damage in a probably underestimated frequency. In such cases, hypercalcemia develops due to a granulomatous foreign body reaction with extrarenal production of calcitriol. In the present report, we describe the cases of two patients who received injections of large volumes of PMMA and developed severe hypercalcemia and advanced chronic kidney disease. These reports highlight the importance of adhering to regulations regarding the use of PMMA and properly informing patients of the possibility of complications before undertaking such procedures.

Resumo Injeções de preenchimento de caráter estético são procedimentos comuns em cirurgia plástica em todo o mundo. O polimetilmetacrilato (PMMA) é um material de preenchimento aprovado apenas para procedimentos minimamente invasivos no tecido facial, e está entre as substâncias injetáveis mais frequentemente usadas para fins estéticos. A injeção de um grande volume de PMMA pode levar ao desenvolvimento de hipercalcemia grave e lesão renal crônica em uma frequência provavelmente subestimada. Nesses casos, a hipercalcemia se desenvolve devido a uma reação granulomatosa de corpo estranho, secundária à produção extrarenal de calcitriol. No presente artigo, descrevemos os casos de dois pacientes que receberam injeções de grandes volumes de PMMA e desenvolveram hipercalcemia grave e doença renal crônica avançada. Esses relatos destacam a importância de seguir as regulamentações sobre o uso do PMMA e informar adequadamente os pacientes sobre a possibilidade de complicações antes de realizar tais procedimentos.