Effects of different polishing procedures on the surface roughness and hardness of polyether ether ketone (PEEK) / Efecto de diferentes procedimientos de pulido en la rugosidad y dureza de superficie de un material a base de poliéter éter acetona (PEEK)

ABSTRACT: There is insufficient information about the chairside polishing methods of polyether ether ketone material. Therefore, it is aimed in this study to investigate the effects of different polishing processes on polyether ether ketone surface roughness and hardness. A total of 66 disc-shaped specimens made of polyether ether ketone were used in this study. The specimens were polished conventionally and randomly divided into three groups (n=22). One group was designated as the control group, and no further treatment was applied. In the other two groups, the specimens' surfaces were abraded with diamond burs and polished using two different polishing kits. Their surface roughness and Vickers hardness were measured, and environmental scanning electron microscopy and atomic force microscopy examinations were performed. The data were statistically analysed using analysis of variance and Tukey's honest significant difference test (α=0.05). There were no statistically significant differences between the control and polishing kit groups in terms of either surface roughness or Vickers hardness (p>0.05). The polishing kits can be used reliably and effectively for polishing polyether ether ketone materials.

RESUMEN: No existe información suficiente sobre los métodos de pulido del material poliéter éter cetona. Por tanto, este estudio tiene como objetivo evaluar el efecto de diferentes procedimientos de pulido sobre la rugosidad y dureza de superficie de un material a base de poliéter éter acetona. Un total de 66 muestras en forma de disco fueron realizadas. Los especímenes fueron divididos en tres grupos (n=22). Un grupo fue designado como grupo de control, siendo que no se aplicó ningún tratamiento. En los otros dos grupos, las superficies de las muestras se lijaron con fresas de diamante y se pulieron con dos kits de pulido diferentes. Se investigó la rugosidad de superficie y la dureza Vickers en los diferentes grupos. También fueron evaluadas muestras representativas en microscopía electrónica de barrido y microscopía de fuerza atómica. Los datos se analizaron estadísticamente mediante el análisis de varianza (ANOVA) y el método de Tukey (α=0.05). No hubo diferencias estadísticamente significativas entre los grupos en términos de rugosidad de superficie o Dureza Vickers (p>0,05). Los kits de pulido se pueden utilizar de forma eficaz para el pulido de materiales a base de poliéter éter acetona.

Evaluation of the effects auricular reconstruction with Medpor combined with hearing rehabilitation / 中华耳鼻咽喉头颈外科杂志

Objective: To investigate the clinical effects of single-stage auricular reconstruction and hearing rehabilitation in children with microtia and external auditory canal atresia. Methods: Sixty eight cases of microtia with external auditory canal atresia (53 males and 15 females, age from 7 to 12 years, with a median age of 8.8 years), who received operations in Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine from July 2017 to December 2019 were collected.A total of 28 cases received auricle reconstruction with high-density polyethylene (Medpor) framework and hearing reconstructions, among which 20 patients received the traditional external auditory canal and middle ear repair (EACR), and eight patients were implanted bone conduction device bone bridge(BB) simultaneously.In the control group, 40 patients only received Medpor frame implantation for auricle plasty. Postoperative changes in auricle morphology and auditory function and postoperative complications were evaluated. Results: After three to thirty months follow-ups, the auricles shape recovered well in all three groups. The average scores of 14 fine structures in the auricles were 9.43(EACR) and 10.67(BB) points. The average score of auricle symmetry were 6.83(EACR) and 6.00(BB) points. There was no significant difference compared to the auricle reconstruction group (8.23/6.20 points). P>0.05. After surgery, the average hearing improvement in the BB group was 43.33 dB HL and the average speech recognition threshold declined 42.28 dB HL. In the EACR group, the average hearing improvement was 4.13 dB HL and the average speech recognition threshold declined 11.36 dB HL. No vertigo, tinnitus, cerebrospinal fluid leakage and other complications occurred in all the patients. In the EACR group, sensorial hearing loss, auricle stent fracture, ear canal restenosis and ear canal atresia occurred in one patient respectively. In the auricle group, one auricle stent exposure and one facial branch nerve injury occurred. Nearly ten patients had difficulty in hair growth at scalp incisions. Conclusions: The operation of single-stage auricular reconstruction and hearing rehabilitation for microtia is feasible. The methods of hearing reconstruction should be determined by evaluating the development of the inner and middle ear of the patients. For those with poor mastoid development, bone bridge implantation is recommended to achieve a stable and significant hearing effect.

Does the addition of vitamin E to conventional UHMWPE improve the wear performance of hip acetabular cups? Micro-Raman characterization of differently processed polyethylene acetabular cups worn on a hip joint simulator

In knee replacements, vitamin E-doped ultra-high molecular weight polyethylene (UHMWPE) shows a better wear behavior than standard UHMWPE. Therefore, different sets of polyethylene (PE) acetabular cups, i.e. standard UHMWPE and cross-linked polyethylene irradiated with 50 kGy and 75 kGy, were compared, at a molecular level, with vitamin E-doped UHMWPE to evaluate their wear performance after being tested on a hip joint simulator for five million cycles. Unworn control and worn acetabular cups were analyzed by micro-Raman spectroscopy to gain insight into the effects of wear on the microstructure and phase composition of PE. Macroscopic wear was evaluated through mass loss measurements. The data showed that the samples could be divided into two groups: 1) standard and vitamin E-doped cups (mass loss of about 100 mg) and 2) the cross-linked cups (mass loss of about 30-40 mg). Micro-Raman spectroscopy disclosed different wear mechanisms in the four sets of acetabular cups, which were related to surface topography data. The vitamin E-doped samples did not show a better wear behavior than the cross-linked ones in terms of either mass loss or morphology changes. However, they showed lower variation at the morphological level (lower changes in phase composition) than the UHMWPE cups, thus confirming a certain protecting role of vitamin E against microstructural changes induced by wear testing.

Preparation and evaluation of schisandrin B-loaded F127 modified lipid-polymer nanoparticles for inhibition of breast cancer lung metastasis / 中国中药杂志

In the current study, schisandrin B(SchB)-loaded F127 modified lipid-polymer hybrid nanoparticles(SchB-F-LPNs) were developed to improve the inhibition of breast cancer lung metastasis. Modified nanoprecipitation method was used to prepare SchB-F-LPNs. The nanoparticles were spherical in shape with shell-core structure by TEM observation. SchB-F-LPNs showed a mean particle size of(234.60±6.11) nm with zeta potential of(-5.88±0.49) mV. XRD results indicated that SchB existed in the nanoparticles in an amorphous state. The apparent permeability coefficient through porcine mucus of F-LPNs was 1.43-fold of that of LPNs as shown in the in vitro mucus penetration study. The pharmacokinetics study showed that the C_(max) of SchB was(369.06±146.94) μg·L~(-1),(1 121.34±91.65) μg·L~(-1) and(2 951.91±360.53) μg·L~(-1) respectively in SchB suspensions group, SchB-LPNs group and SchB-F-LPNs group after oral administration in rats. With SchB suspensions as the reference formulation, the relative bioavailability of SchB-F-LPNs was 568.60%. SchB-F-LPNs inhibited the morphological change during transforming growth factor-β1(TGF-β1)-induced epithelial-mesenchymal transition. In addition, SchB-F-LPNs significantly decreased the number of metastatic pulmonary nodules in 4 T1 tumor-bearing mice, suggesting that SchB-F-LPNs may inhibit the metastasis of breast cancer. These results reveal the promising potential of SchB-F-LPNs in treatment of breast cancer lung metastasis.

Comparison of Wear Rate between Ceramic-on- Ceramic, Metal on Highly Cross-linked Polyethylene, and Metal-on-Metal Bearings / Comparação da taxa de desgaste entre componentes de cerâmica sobre cerâmica, de metal sobre polietileno de alta ligação cruzada e de metal sobre metal

Abstract Objective Currently, there is a lack of evidence on the medium-term follow-up of cementless total hip arthroplasty (THA) using metal on highly cross-linked polyethylene (MoP), ceramic-on-ceramic (CoC), and metal-on-metal (MoM) bearings. Our aim was to calculate the 5- to 10-year wear rate and the incidence rate of osteolysis for 3 types of bearings. Methods A total of 77 patients underwent MoP, 105 underwent ceramic CoC, and 55 underwent MoM THAs. The average patient age at the time of surgery was 64.7, 55.9, and 59.9 years old in the MoP, CoC, and MoM bearings, respectively. Clinical and radiologic measurements at a mean follow-up of 7.6 years were analyzed. Results The mean postoperative Harris hip scores showed no difference among the groups. The mean annual liner wear rates were 0.0160, 0.0040 and 0.0054 mm/year in MoP, CoC bearings, and MoM bearings, with that of CoC bearings being significantly lower than the others. Osteolysis (14.5%) among MoM bearings was significantly more frequently observed compared with the others. Kaplan-Meier survival at 10 years with implant loosening, or revisionTHA as the endpoint, was 96.1% (95% confidence interval [CI]: 88.4-98.7) forMoP, 98.6% (95% CI: 90.3-98.6) for CoC bearing, and 98.2% (95% CI: 88.0-99.7) for MoM bearings (p = 0.360). Conclusion Excellent clinical and radiological outcomes were obtained for MoP and CoC bearings.

Resumo Objetivo Hoje, não há evidências sobre o acompanhamento em médio prazo da artroplastia total do quadril (ATQ) não cimentada com componentes de polietileno de alta ligação cruzada (highly cross-linked) sobre metal (MoP, na sigla em inglês), de cerâmica sobre cerâmica (CoC, na sigla em inglês), e de metal sobre metal (MoM, na sigla eminglês). Nosso objetivo foi calcular a taxa de desgaste entre 5 a 10 anos e a taxa de incidência de osteólise nos 3 tipos de componentes. Métodos Um total de 77 pacientes foram submetidos a ATQ com componentes de MoP; 105 foram submetidos ao mesmo procedimento com componentes de CoC, e 55 foram submetidos à ATQ com componentes de MoM. A média de idade dos pacientes no momento da cirurgia foi de 64,7, 55,9 e 59,9 anos nos grupos de componentes MoP, de CoC, e de MoM, respectivamente. Asmedidas clínicas e radiológicas emumperíodo médio de acompanhamento de 7,6 anos foram analisadas. Resultados As pontuações médias de Harris no período pós-operatório não mostraram diferença entre os grupos. As taxas médias anuais de desgaste do revestimento foram de 0,0160, 0,0040 e 0,0054 mm/ano em componentes de MoP, de CoC, e de MoP, respectivamente; a taxa de desgaste dos componentes de CoC foi significativamente menor do que as dos demais. A osteólise (14,5%) nos componentes de MoM foi significativamente mais frequente em comparação aos demais. A sobrevida de Kaplan- Meier aos 10 anos comafrouxamento do implante ou revisão da ATQ como desfecho foi de 96,1% (intervalo de confiança [IC] de 95%: 88,4-98,7) nos componentes de MoP, de 98,6% (IC95%: 90,3-98,6) nos componentes de CoC, e de 98,2% (IC95%: 88,0-99,7) nos componentes de MoM (p = 0,360). Conclusão Os resultados clínicos e radiológicos de componentes de MoP e de CoC foram excelentes.

Antifungal efficiency of chemically and thermally-activated acrylic resins after surface treatment using poly (diallyldimethylammonium chloride)

Abstract INTRODUCTION: Acrylic resins are used in the preparation of facial prostheses and may be colonized by fungi. Here, we verified the antifungal efficacy of this material after surface treatment using poly (diallyldimethylammonium chloride). METHODS: Acrylic resin specimens with and without surface treatment were subjected to tests for fungistatic and fungicidal activities. Standard strains of Candida albicans and Aspergillus niger were used. RESULTS: After surface treatment, the fungistatic and fungicidal efficacies of the resins against C. albicans and fungistatic action against A. niger were verified. CONCLUSIONS: The surface treatment was a determinant of the antifungal activity of the material.

Comparación del confort de dos protectores bucales en jugadores de fútbol americano / Comparing the comfort of two mouth protectors in football players

Los deportes de contacto aumentan el riesgo de traumatismo causando alteraciones funcionales, estéticas y psicológicas. Los protectores bucales son parte del equipo de seguridad que protegen al deportista de estos accidentes, es importante que brinde confort para lograr el mejor rendimiento físico. Objetivo: Comparar el confort de los jugadores de fútbol americano con el uso de protectores prefabricados y protectores personalizados. Metodología: Se realizó un estudio cuasiexperimental, analítico y prospectivo donde se incluyeron 15 jugadores de futbol americano de la Facultad de Estudios Superiores Acatlán, UNAM, que firmaron consentimiento informado. La autora principal de este proyecto fabricó los protectores bucales superiores con hoja de copolímero de etilvinilacetato (EVA) #35. El protector prefabricado fue de silicón. Los jugadores realizaron dos prácticas de entrenamientos donde hicieron 30 minutos de carrera, 15 de estiramiento, 60 de fuerza y destreza en donde requerían de estar en constante comunicación verbal y 30 de cardiovascular en gimnasio (usaron un protector en cada entrenamiento). Se aplicó un cuestionario ­previamente validado por consenso de expertos­ para evaluar el confort en la respiración, lenguaje, náuseas, adaptación, comodidad e hidratación bucal con cada tipo de protector. La información se analizó en el programa SPSS v19.0; se usaron proporciones para las variables cualitativas y medidas de tendencia central y dispersión para las cuantitativas. Para comparar el confort con el uso de ambos protectores se empleó la prueba χ2, con un nivel de significancia p < 0.05. Resultados: La media de edad fue de 20 ± 2 años. Con el protector personalizado 11 jugadores (0.73) refirieron que respiraron y hablaron mejor, sintieron menos náusea 12 (0.80), mejor adaptación 11 (0.73) y mayor comodidad 12 (0.80) que, con el uso de protector bucal prefabricado, encontrando diferencias estadísticamente significativas (p < 0.05) y ocho (0.53) refirió menos hidratación bucal (p > 0.05). Doce (0.80) de los jugadores mencionaron tener mayor confort con el protector personalizado. Conclusiones: Con la metodología empleada y en la muestra estudiada, el uso de un protector bucal personalizado fabricado con hoja de copolímero de etilvinilacetato (EVA) #35 ofrece una mejor adaptación y comodidad, después de dos prácticas de entrenamiento (AU)

The contact sports, increase the risk of trauma causing functional, aesthetic and psychological alterations, mouth guards are part of the safety equipment that protects the athlete from this kind of accidents, it is also important that the mouth guard had to provides comfort, for achieve a best physical performance. Objective: Make the comparison with the comfort of American football players with the use of prefabricated protectors and customized protectors. Method: A quasi-experimental, analytical and prospective study was carried out, including 15 American football players from the Facultad de Estudios Superiores Acatlán, UNAM, who signed an informed consent. The lead author of this project manufactured the upper mouth guards with ethylvinylacetate (EVA) #35 copolymer foil. The prefabricated protector was made of silicone. The players performed two practice sessions where they did 30 minutes of running, 15 of stretching, 60 of strength and skill where they required being in constant verbal communication and 30 of cardiovascular in a gymnasium (they used a protector in each training). A questionnaire ­previously validated by expert consensus­ was applied to evaluate comfort in breathing, language, nausea, adaptation, comfort and oral hydration with each type of protector. The information was analyzed in the program SPSS v19.0; proportions were used for the qualitative variables and measures of central tendency and dispersion for the quantitative ones. To compare the comfort with the use of both protectors the test χ2 was used, with a level of signifi cance p < 0.05. Results: The mean age was 20 ± 2 years. With the personalized protector, 11 players (0.73) reported that they breathed and spoke better, feeling less nausea 12 (0.80), better adaptation 11 (0.73) and greater comfort 12 (0.80) than with the use of prefabricated mouth guards, fi nding statistically signifi cant diff erences (p < 0.05) and 8 (0.53) reported less oral hydration (p > 0.05). 12 (0.80) of players mentioned having more comfort with the custom protector. Conclusions: The use of a personalized mouth guard off ers better fi t and comfort made with sheet copolymer of ethylvinylacetate, after two training practices (AU)

Reconstruction of the orbital fracture with enophthalmos using customized titanium mesh combined with Medpor / 华西口腔医学杂志

<p><b>OBJECTIVE</b>This study aims to evaluate the effect of customized titanium mesh, which was designed by mirror imaging and rapid prototyping technique, with Medpor applied for orbital fracture with enophthalmos.</p><p><b>METHODS</b>Orbital axial, coronal, and sagittal CT scan, and three-dimension CT examination were performed routinely in. 18 cases of orbital fracture with enophthalmos preoperatively. Based on the CT data, prosthesis model was designed by reverse engineering and rapid prototyping technique. The customized titanium mesh and Medpor were applied for orbital reconstruction and enophthalmos correction. Orbital reduction and globe projection were evaluated by postoperative CT scan and clinical follow-up visits.</p><p><b>RESULTS</b>CT scans revealed that the customized titanium mesh with Medpor had great accuracy to reconstruct the orbital fracture and correct the enophthalmos in all patients without serious complications. The eye and facial appearance and function recovered significantly. No serious complication occurred in the operation and after operation.</p><p><b>CONCLUSION</b>The customized titanium mesh, based on mirror imaging and rapid prototyping technique, can accurately reconstruct the orbital fractures with enophthalmos. The application of Medpor can effectively correct enophthalmos and eyeball mobility malformation.</p>

Tribología moderna en artroplastía total de cadera: pros y contras / Modern tribology in total hip arthroplasty: pros and cons

Los productos de desgaste y las reacciones adversas que se generan en las superficies de rodamiento constituyen uno de los mayores desafíos en las sustituciones protéticas, ya que cada día se someten a mayores demandas por un cada vez mayor número de pacientes jóvenes y adultos mayores con expectativas de vida prolongadas y notable actividad. El objetivo de esta revisión es analizar los pros y contras en cuanto a los avances de los componentes de rodamiento de las superficies articulares de las artroplastias totales de cadera contemporáneas. También se discutirán las estrategias que se han seguido a lo largo del tiempo, sus problemas, resultados y el papel que desempeña el cirujano en la prescripción del par tribológico que mejor se adapte a las necesidades de cada paciente. Al final se hacen recomendaciones prácticas para prescripción y manejo de los pares articulares contemporáneos en artroplastia total de cadera.

The wear products and adverse reactions that occur on bearing surfaces represent one of the greatest challenges in prosthetic replacements, as the latter experience increasing demands due to the large number of young and older adult patients that have a long life expectancy and remarkable activity. The purpose of this review is to analyze the pros and cons of the new advances in the bearing components of the articular surfaces of current total hip arthroplasties. We also discuss the strategies used historically, their problems, results and the surgeon's role in prescribing the tribologic couple that best fits each patient's needs. We conclude with practical recommendations for the prescription and management of the latest articular couples for total hip arthroplasty.

A novel approach in treating horizontally fractured canine using RIBBOND splint and MTA as an obturating material and intra-radicular splint: A case report.

Radicular fractures in permanent teeth are uncommon injuries among dental traumas, being only 0.5-7% of the cases. Management of horizontal root fractures presents a formidable challenge for clinicians because of the difficulty of achieving a stable reunion of fracture fragments. This case report presents the management of horizontally fractured canine by approximation of fracture fragments, fiber splinting, and use of MTA - both as an obturating material and intra-radicular splint. Short-term follow-up of the case showed promising results both clinically and radiographically.

The application of medpor and split-thickness skin graft in formation of cranioauricular sulcus during auricular reconstruction with Nagata method / 中华整形外科杂志

<p><b>OBJECTIVE</b>To investigate the application of medpor and split-thickness skin graft in formation of cranioauricular sulcus during auricular reconstruction with Nagata method.</p><p><b>METHODS</b>The first stage operation was fulfilled according to the Nagata two-stage method which involves fabrication and grafting of the costal cartilage framework. The second-stage ear elevation operation was undertaken 6 months later to form the cranioauricular sulcus. Split-thickness skin was taken from temporal and accipital area. After releasing the auricular framework and transplanting C shaped medpor at the rear side of framework, the temporaparietal fascia flap was transferred to cover postauricular medpor and framework. Then the split-thickness skin graft was implant on the fascia surface.</p><p><b>RESULTS</b>From July 2010 to August 2012, 20 cases (22 ears) were treated. Partial necrosis of temporaparietal fascia flap and framework exposure happened in 1 case. Successful ear reconstruction was achieved in other cases with satisfactory cranioauricular sulcus during the follow-up period of 6-18 months (average, 13 months).</p><p><b>CONCLUSIONS</b>The application of medpor and split-thickness skin graft in the ear elevation of Nagata method for auricular reconstruction for microtia can achieve satisfactory results. It not only avoids the obvious scar in the donor site due to harvesting full-thickness and intermediate-thickness skin, but also reduces chest trauma due to harvesting costal cartilage.</p>

Problems Associated with Alloplastic Materials in Rhinoplasty

PURPOSE: Augmentation rhinoplasty using alloplastic materials is a relatively common procedure among Asians. Silicon, expanded polytetrafluoroethylene (Gore-tex(R)), and porous high density polyethylene (Medpor(R)) are most frequently used materials. This study was conducted to analyze revisional rhinoplasty cases with alloplastic materials, and to investigate the usage of alloplastic materials and their complications. We also reviewed complications caused by various materials used in plastic surgery while operating rhinoplasty. MATERIALS AND METHODS: We report 581 cases of complications rhinoplasty with alloplastic implants and review of the literature available to offer plastic surgeons an overview on alloplastic implant-related complications. RESULTS: Among a total 581 revisional rhinoplasty cases reviewed, the alloplastic materials used were silicone implants in 376, Gore-tex(R) in 183, and Medpor(R) in 22 cases. Revision cases and complications differed according to each alloplastic implant. CONCLUSION: Optimal alloplastic implants should be used in nasal structure by taking into account the properties of the materials for the goal of minimizing their complications and revision rates. A thorough understanding of the mechanism involved in alloplastic material interaction and wound healing is the top priority in successfully overcoming alloplastic-related complications.

Puente adhesivo en paciente con labio leporino y fisura velopalatina: una solución temporal con compromiso estético / Adhesive bridge in a patient with cleft lip and palate: a temporary solution with esthetic commitment

En la actualidad el aumento de la demanda estética y la necesidad de procedimientos mínimamente invasivos ha llevado a un aumento de la técnica adhesiva. Ribbond® es una marca de fibra de polietileno que permite un eficiente traspaso de fuerzas, es virtualmente plegable y se adapta fácilmente a la morfología dentaria y al contorno del arco dentario. Dentro de sus principales características podemos encontrar: Biocompatibilidad, inerte, translúcido y durable. Dentro de la odontología se le han dado distintos usos para esta fibra, ya sea como mantenedor de espacio, puente adhesivo, poste y núcleo endodóntico, ferulización, restauraciones tipo inlay y estabilización postortodóncica. En el caso de los pacientes fisurados se ha hecho relevante el uso de Ribbond® como puente adhesivo ya que permite mejorar la estética y rehabilitar temporalmente los espacios desdentados causados por la ausencia de un incisivo, principalmente una vez terminado el tratamiento de ortodoncia y en espera de una rehabilitación definitiva, aún más cuando el paciente no ha terminado su crecimiento y desarrollo. En este artículo se presenta un caso clínico de un paciente con labio leporino y fisura velopalatina operado demostrativo de la técnica de rehabilitación con Ribbond®.

Today the increasing demand of aesthetic and minimally invasive procedures has led to a boom of the adhesive technique. Ribbond® is a polyethylene fiber that allows an efficient transfer of forces, is virtually foldable and is easily adapted to tooth morphology and dental arch contour. Among its main features we can find: Biocompatibility, inert, translucent and durable. In dentistry, different uses have been given to this fiber, whether as space maintainer, adhesive bridge, endodontic post and core, splinting, inlay type restorations and postorthodontic stabilization. In the case of cleft lip and palate patients the use of Ribbond® as an adhesive bridge has become relevant, as it improves aesthetics and temporarily rehabilitates the edentulous spaces caused by the absence of an incisor. It is used especially after completion of the orthodontic treatment and waiting for a final rehabilitation, even when the patient has not completed their growth and development. This article presents a clinical case of a patient with lip and cleft palate operated with the rehabilitation technique using Ribbond®.

Fatigue resistance, debonding force, and failure type of fiber-reinforced composite, polyethylene ribbon-reinforced, and braided stainless steel wire lingual retainers in vitro / 대한치과교정학회지

OBJECTIVE: To analyze the fatigue resistance, debonding force, and failure type of fiber-reinforced composite, polyethylene ribbon-reinforced, and braided stainless steel wire lingual retainers in vitro. METHODS: Roots of human mandibular central incisors were covered with silicone, mimicking the periodontal ligament, and embedded in polymethylmethacrylate. The specimens (N = 50), with two teeth each, were randomly divided into five groups (n = 10/group) according to the retainer materials: (1) Interlig (E-glass), (2) everStick Ortho (E-glass), (3) DentaPreg Splint (S2-glass), (4) Ribbond (polyethylene), and (5) Quad Cat wire (stainless steel). After the recommended adhesive procedures, the retainers were bonded to the teeth by using flowable composite resin (Tetric Flow). The teeth were subjected to 10,00,000 cyclic loads (8 Hz, 3 - 100 N, 45degrees angle, under 37 +/- 3degrees C water) at their incisoproximal contact, and debonding forces were measured with a universal testing machine (1 mm/min crosshead speed). Failure sites were examined under a stereomicroscope (x40 magnification). Data were analyzed by one-way analysis of variance. RESULTS: All the specimens survived the cyclic loading. Their mean debonding forces were not significantly different (p > 0.05). The DentaPreg Splint group (80%) showed the highest incidence of complete adhesive debonding, followed by the Interlig group (60%). The everStick Ortho group (80%) presented predominantly partial adhesive debonding. The Quad Cat wire group (50%) presented overlying composite detachment. CONCLUSIONS: Cyclic loading did not cause debonding. The retainers presented similar debonding forces but different failure types. Braided stainless steel wire retainers presented the most repairable failure type.

O uso de implantes orbitários de polietileno granulado de ultra-alto peso molecular no reparo de cavidades anoftálmicas / The use of orbital ultra-high molecular weight granulated polyethylene implants in the anophthalmic socket repair

OBJETIVO: Alterações oculares, em especial a perda de volume nas cavidades evisceradas, promovem uma série de modificações ao paciente tanto funcional do órgão quanto psicológica e estética. Para tanto a procura de um material de baixo custo e com biocompatibilidade tem sido uma constante na literatura. Portanto, esse trabalho teve como objetivo testar experimentalmente implante de polietileno granulado de ultra-alto peso molecular, material de baixo custo, em órbitas de coelhos submetidos à evisceração cirúrgica em vários tempos experimentais, onde foram avaliados aspectos macroscópicos e microscópicose de toxicidade sistêmica do material. MÉTODOS: Para esse estudo foram utilizados coelhos Oryctolaguscuniculus submetidos à evisceração do globo ocular direito e posteriormente implantados com esfera de polietileno granulado de ultra-alto peso molecular e analisados por 15, 30, 90 e 180 dias pós-implante, com parâmetros macro, microscópios e bioquímicos. Os animais controles foram submetidos ao mesmo procedimento sem, entretanto a colocação do implante. RESULTADOS: Os resultados desse trabalho mostram que o material utilizado no implante de cavidade não apresenta alteração significativa nos parâmetros de peso e bioquímicos quando comparados ao grupo controle. O material implantado apresentou uma grande interação com o tecido do hospedeiro. CONCLUSÃO: Os resultados indicam que implante de polietileno granulado de alto peso molecular desenvolvido por uma indústria nacional tem alto potencial para se realizar testes em humanos.

OBJECTIVE: Ocular changes in special due to volume loss in eviscerated cavities promote several psychological aesthetic and functional alterations to patients. For this reason, searches aiming at finding a material of low cost and biocompatibility have been constantly carried out. Test experimentally the implants constituted of ultra-high molecular weight granular polyethylene oflow cost, in orbits of rabbits subjected to surgical evisceration in several experimental times, evaluating the macro and microscope aspects besides the systemic toxicity of the material. METHODS: In this study we eviscerated the right ocular globe of rabbits of the species Oryctolaguscuniculus, implanted posteriorly a sphere of granular polyethylene of ultrahigh molecular weight and analysed the effects through macro, micro and biochemical parameters during 15, 30, 90 and 180 days after implantation.The control group were submitted the same procedure without the implants. RESULTS: This paper shows that the material used in the cavity does not present significant alteration in the weight and in the biochemistry of the animal; a good assimilation (integration) of the material implanted by the tissue formed was observed inside the implant. CONCLUSION: The results indicate that ultra-high molecular weight granular polyethylene implant developed by a national industry presents excellent integration in the model used supporting further use in tests with humans.

Luxação traumática do bulbo ocular causada por acidente automobilístico / Traumatic eye luxation caused by automobilistic accident

Descreve-se um paciente com trauma ocular grave causada por acidente automobilístico que acarretou luxação total de bulbo ocular.

Description of a patient with grave ocular trauma caused by a traffic accident that it followed by total luxation of the eye.

Research on surface modification and bio-tribological properties of artificial joint / 中南大学学报(医学版)

The bio-tribological properties of an artificial joint can be obviously improved by surface modification technologies. In this paper, the benefits and disadvantages of various surface modification methods-such as surface coating, plasma treatment, surface texture and surface grafting modification-are discussed. The aim of surface coating and/or plasma treatment is to improve the surface hardness of the materials, thus enhancing the wear resistance of artificial joints. However, these technologies do not effectively alleviate stress concentration of material in the short times in which artificial joints bear physiological impact load, resulting in easy fracture. Surface texture serves mainly to improve the lubrication properties through micro-concavities on the material surface for storage lubricant. Surface texturing can realize improvements in bio-tribological properties, but it does not enhance the impact resistance of the joint. Surface grafting modification is implemented mainly by grafting hydrophilic or other specific functional groups to improve the surface hydrophilicity and wetability, thus enhancing lubricating performance and reducing the coefficient of friction.

Auricular reconstruction by soft tissue expansion techniques without skin grafting / 中华整形外科杂志

<p><b>OBJECTIVE</b>To investigate a method of auricular reconstruction by soft tissue expansion techniques without skin grafting.</p><p><b>METHODS</b>Two tissue expanders (50 ml and 70 ml) were implanted under the skin of mastoid in 15 patients with grade II or III microtia. One big expander (100 ml) were implanted under the skin of mastoid in 13 patients with grade I microtia and 3 patients with grade II or III microtia. After skin expansion, the expanders were taken out. The autologous rib cartilage or Medpor scaffolds were implanted. The superior expanded skin flap was used to cover the frontal surface and the upper part of the back surface of the framework. The inferior expanded skin flap was transplanted to cover the lower part of the back surface of the framework. The remained expanded skin flap was transplanted to cover the wound in the lateral of head.</p><p><b>RESULTS</b>No skin graft was needed in all the patients. Epidermis blister occurred at the distal part of flap in one case. No other complication was happened. A follow-up of 6 to 12 months (mean 10.9 months) was carried out in all patients with good cosmetic result when the reconstructed ear underwent second-stage operation. The scar size on the dornor site was (5.2 +/- 0.6) cm2 The satisfactory rate was 90% (28/31).</p><p><b>CONCLUSIONS</b>The expanded skin with this new method is enough for auricular reconstruction without skin grafting, leaving less complication and less scar at donor site.</p>

In vivo Osteogenesis of Cultured Human Periosteal-derived Cells and Polydioxanone/Pluronic F127 Scaffold

The Effect of Tibial Posterior Slope on Contact Force and Ligaments Stresses in Posterior-Stabilized Total Knee Arthroplasty-Explicit Finite Element Analysis

PURPOSE: The purpose of this study is to evaluate the effect of change in tibial posterior slope on contact force and ligament stress using finite element analysis. MATERIALS AND METHODS: A 3-dimensional finite element model for total knee arthroplasty was developed by using a computed tomography scan. For validation, the tibial translations were compared with previous studies. The finite element analysis was conducted under the standard gait cycle, and contact force on ultra-high molecular weight polyethylene (UHMWPE) and stresses on lateral and medial collateral ligaments were evaluated. RESULTS: The tibial translations showed similarity with previous studies. As the tibial posterior slope angle increases, the contact stress area increased and was well distributed, and the contact force on UHMWPE decreased overall. However, the maximum contact force in the case for 10degrees case was greater than those for others. The stresses on ligaments were the greatest and smallest in 0degrees and 10degrees cases, respectively. CONCLUSIONS: The higher tibial posterior slope angle leads to the lower contact stress and more extensive stress distribution overall in posterior-stabilized total knee arthroscopy. However, it does not absolutely mean the smallest contact force. The stresses on ligaments increased with respect to the smaller tibial posterior slope angle.