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Resumen Entre los diferentes materiales cerámicos, el dióxido de zirconio (ZrO2) se destaca, debido a sus aplicaciones en el área médica, química y farmacéutica. Esto es posible al ser un material de carácter anfótero, con tres fases cristalinas: monoclínica, tetragonal y cúbica, las cuales presentan distintas propiedades. El objetivo de este trabajo fue analizar los fundamentos de los diferentes métodos utilizados para la síntesis del ZrO2 y sus aplicaciones biomédicas. Las principales metodologías empleadas son los procesos hidrotérmico, precipitación, solvotérmica y sol-gel. La energía de ultrasonido y la radiación de microondas permiten reducir los tiempos de reacción y proporcionar mayor eficiencia energética a los procesos. El método de síntesis modifica las propiedades del ZrO2, lo cual es aprovechado para desarrollar diferentes aplicaciones, entre ellas destacan reemplazos óseos, prótesis dentales y liberación de fármacos.
Abstract Among the different ceramic materials, zirconium dioxide (ZrO2) stands out, due to its applications in the medical, chemical and pharmaceutical areas. This is possible, since it is an amphoteric material with three crystalline phases: monoclinic, tetragonal and cubic, which have different properties. The objective of this work was to analyze the fundamentals of the different methods used for the synthesis of ZrO2, and its main biomedical applications. The main methodologies used include the hydrothermal, precipitation, solvothermal and sol-gel processes. The use of ultrasound energy and microwave radiation allows the reduction in reaction times, and provides greater energy efficiency to the process and a lower environmental impact. The synthesis method modifies the properties of ZrO2, which is used to develop different applications, including bone replacements, dental prostheses and drug release.
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Objective: the purpose of this multicenter retrospective study was to report on survival, success, and complication rates in monolithic zirconia restorations on teeth and implants. Materials and Methods: data on 671 monolithic zirconia restorations was collected by five prosthodontists from three different specialty practice centers, including a dental school and two private practice centers. Restorations included single crowns and multiple-unit fixed dental prostheses on teeth and implants in the posterior area (premolar and molars). Follow-up time was up to 62 months. Results: mean follow-up time was 28.1±12.9 months. A total of 671 units, 534 single crowns, and 137 multi-unit restorations. Cumulative survival and success rates at 5 years were 97.4%, and 93.8% respectively. Complications presented in 11 restorations out of 671 and included: decementation, abutment screw loosening, restoration crack, restoration fracture, and tooth fracture. No significant differences were observed between tooth-supported and implant-supported restoration (p=0.42), single crowns and multiple-unit restorations (p=0.07), bruxers and non-bruxers (p=0.57). Patients with group function occlusal scheme had significantly less survival rates (p=0.001). Conclusion: the use of monolithic zirconia for restorations on the posterior teeth and implants seems to be promising as it provides a durable solution with a low rate of complications.
Objetivo: el propósito de este estudio retrospectivo multicéntrico fue informar sobre las tasas de supervivencia, éxito y complicaciones en restauraciones monolíticas de circonio en dientes e implantes. Materiales y Métodos: cinco prostodoncistas recolectaron datos de 671 restauraciones monolíticas de zirconia de tres centros de práctica especializados: una escuela de odontología y dos centros de práctica privados. Las restauraciones incluyeron coronas individuales y prótesis dentales fijas de unidades múltiples en dientes e implantes en el área posterior (premolares y molares). El tiempo de seguimiento fue de hasta 62 meses. Resultados: el tiempo medio de seguimiento fue de 28,1±12,9 meses. Un total de 671 unidades, 534 coronas individuales y 137 restauraciones de unidades múltiples. La supervivencia acumulada y las tasas de éxito a los 5 años fueron del 97,4% y del 93,8%, respectivamente. Las complicaciones se presentaron en 11 restauraciones de 671 e incluyeron: fracaso del cementado, aflojamiento del tornillo del pilar, grieta en la restauración, fractura de restauración y fractura de dientes. No se observaron diferencias significativas entre la restauración con soporte dental y con implante (p=0,42), coronas individuales y restauraciones de unidades múltiples (p=0,07), pacientes con bruxismo y sin bruxismo (p=0,57). Los pacientes con esquema oclusal de función grupal tuvieron tasas de supervivencia significativamente menores (p= 0,0 01). Conclusión: el uso de zirconia monolítica para restauraciones en los dientes posteriores y en implantes parece ser prometedor, ya que proporciona una solución duradera con una baja tasa de complicaciones.
Subject(s)
Humans , Zirconium/chemistry , Dental Implants, Single-Tooth , Dental Implantation, Endosseous , Tooth Fractures , Retrospective Studies , Treatment Outcome , Dental Prosthesis Retention/statistics & numerical data , Crowns , Dental CementsABSTRACT
Objective: To construct bone morphogenetic protein 2 (BMP-2) gelatin/chitosan hydrogel sustained-release system, co-implant with induced pluripotent stem cells (iPS) derived mesenchymal stem cells (MSCs) to hydroxyapatite (HA)/zirconium dioxide (ZrO 2) bio porous ceramic foam, co-culture in vitro, and to explore the effect of sustained-release system on osteogenic differentiation of iPS-MSCs. Methods: BMP-2 gelatin/chitosan hydrogel microspheres were prepared by water-in-oil solution. Drug encapsulation efficiency, drug loading, and in vitro sustained release rate of the microspheres were tested. HA/ZrO 2 bio porous ceramic foam composite iPS-MSCs and BMP-2 gelatin/chitosan hydrogel sustained release system co-culture system was established as experimental group, and cell scaffold complex without BMP-2 composite gelatin/chitosan hydrogel sustained release system as control group. After 3, 7, 10, and 14 days of co-culture in the two groups, ALP secretion of cells was detected; gene expression levels of core binding factor alpha 1 (Cbfa1), collagen type Ⅰ, and Osterix (OSX) were detected by RT-PCR; the expression of collagen type Ⅰ was observed by immunohistochemical staining at 14 days of culture; and cell creep and adhesion were observed by scanning electron microscopy. Results: BMP-2 gelatin/chitosan hydrogel sustained-release system had better drug encapsulation efficiency and drug loading, and could prolong the activity time of BMP-2. The secretion of ALP and the relative expression of Cbfa1, collagen type Ⅰ, and OSX genes in the experimental group were significantly higher than those in the control group at different time points in the in vitro co-culture system ( P<0.05). Immunohistochemical staining showed that the amount of fluorescence in the experimental group was significantly more than that in the control group, i.e. the expression level of collagen type Ⅰ was higher than that in the control group. The cells could be more evenly distributed on the materials, and the cell morphology was good. Scanning electron microscopy showed that the sustained-release system could adhere to cells well. Conclusion: iPS-MSCs have the ability of osteogenic differentiation, which is significantly enhanced by BMP-2 gelatin/chitosan hydrogel sustained-release system. The combination of iPS-MSCs and sustained-release system can adhere to the materials well, and the cell activity is better.
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Objective: To compare tumor growth and drug targeting of zirconium dioxide nanoparticles loaded doxorubicin (DOX@ZrO2) and free doxorubicin (DOX-Free) administered through different routes of hepatic VX2 transplanted tumor in rabbit models. Methods: A total of 25 rabbit models of hepatic VX2 transplanted tumor were established and randomly divided into 5 groups, including group A (DOX@ZrO2 via hepatic artery), group B (DOX@ZrO2 via peripheral vein), group C (DOX-free via hepatic artery), group D (DOX-free via peripheral vein) and group E (untreated group). Tumor volumes were measured with CT scanning 1 day, 3 days and 6 days after drug administration, and the ratio of tumor volume were compared between 3 days and 1 day, 6 days and 3 days, as well as 6 days and 1 day. One-way ANOVO analysis was used for multi-group comparison and LSD or SNK method was used for pairwise comparison. Histological observations of isolated heart specimen were performed to evaluate the cardiotoxicity of the drug in each group. Results: There was no statistic difference of tumor volume ratio between 3 days and 1 day, nor between 6 days and 3 days (F=2.056, 1.906, P=0.125, 0.149), while statistic difference of tumor volume ratio was found between 6 days and 1 day after drug administration (F=4.230, P=0.012). The tumor volume ratio in group A was significantly lower than that in the other groups (P0.05) except between group B and E. Histological observation showed that the myocardium of group A and group B was just a little or no damage, while of group C and group D were severe damaged. Conclusion: Combining traditional super selective hepatic arterial chemotherapy targeting surgical treatment method with nano drug carrier, tumor growth of hepatic VX2 transplanted tumor in rabbit model can be delayed, and the drug targeting can be improved. Moreover, the cardiotoxicity caused by doxorubicin can be effectively reduced.
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O uso de pilares e infraestruturas cerâmicas pelo método CAD/CAM tem se popularizado nas reabilitações, seja para implantes ou dentes naturais. O objetivo deste estudo foi avaliar a adaptação de um pilar de hexágono externo obtido em zircônia através do processo CAD/CAM. Para tanto, foram confeccionados dez pilares em zircônia (grupo teste) de um mesmo arquivo obtido através do escaneamento de um análogo de implante HE 4,1. Foram utilizados dez pilares em titânio da mesma empresa que produziu o análogo (grupo controle). Cada amostra foi instalada no análogo com torque de 32 Ncm, sendo levadas a microscopia óptica, onde foram medidos três pontos para cada amostra. Os resultados demonstraram média de desadaptação de 3,88 µm no grupo teste e 4,36 µm no grupo controle, ficando ambas abaixo do limite preconizado pela literatura. Este trabalho permitiu concluir que é possível conseguir adaptação satisfatória com pilares unitários em zircônia obtidos pelo método CAD/CAM.
The use of ceramic frameworks and abutments has become popular in tooth- or implant-supported oral rehabilitations. The aim of this study was to evaluate the margin fit of a CAD/CAM generated, external hex zirconia abutment. For this, ten zirconia abutments (test group) were obtained from scanning of a 4.1mm implant replica. Ten titanium abutments served as control. Each sample was tightened to 32 Ncm and three regions observed under light microscopy. The mean margin fit levels were 3,88 micrometers and 4.36 mm in the control group, being those values lower than that reported in the literature. It can be concluded that satisfactory fit can be found on CAD/CAM single, zirconia abutments