Journal of Applied Biomaterials & Functional Materials

Microwave and water bath postpolymerization have been suggested as methods to improve the mechanical properties of heat and autopolymerizing acrylic resins. However, the effects of autoclave heating on the fracture properties of autopolymerizing acrylic resins have not been investigated.

The aim of this study was to assess the effectiveness of various autoclave postpolymerization methods on the fracture properties of 3 different autopolymerizing acrylic resins.

Forty-two specimens of 3 different autopolymerizing acrylic resins (Orthocryl, Paladent RR and Futurajet) were fabricated (40x8x4mm), and each group was further divided into 6 subgroups (n=7). Control group specimens remained as processed (Group 1). The first test group was postpolymerized in a cassette autoclave at 135°C for 6 minutes and the other groups were postpolymerized in a conventional autoclave at 130°C using different time settings (5, 10, 20 or 30 minutes). Fracture toughness was then measured with a three-point bending test. Data were analyzed by ANOVA followed by the Duncan test (α=0.05).

The fracture toughness of Orthocryl and Paladent-RR acrylic resins significantly increased following conventional autoclave postpolymerization at 130°C for 10 minutes (P<.05). However, the fracture toughness of autoclave postpolymerized Futurajet was not significantly different than its control specimens (P<.05). The fracture toughness of Futurajet was significantly less than Paladent RR and Orthocryl specimens when autoclaved at 130°C for 10 minutes.

Within the limitations of this study, it can be suggested that autoclave postpolymerization is an effective method for increasing the fracture toughness of tested autoploymerized acrylic resins.

The effective results shown in the porous systems of tantalum employed for the use of osseointegrates has been demonstrated by means of animal experimentation. However, there is a total lack of any research studies on the osseointegration of tantalum implants from retrieval of the same after a period of time whereby the material had been implanted within the human body.

For this study, five rod implants used for the treatment of avascular necrosis of the femoral head were retrieved following collapse of the femoral head and conversion to total hip arthroplasty. The time of implantation ranged between six weeks and twenty months.

Observation during this study has confirmed the effectiveness of osseointegration within this period of time. New bone was observed around and within the porous system of the on rod devices at retrieval date. The bone ingrowth, however, proved to be slower and less intense than that resulting within animal species during the first few months after implantation.

Nevertheless, the results obtained in the quantitative assessment of this process proved to be similar to those results achieved by other authors in previous experimental work studies.

This paper compares the interaction between the nanomaterial containing calcium phosphate/poly-dl-lactide-co-glycolide (N-CP/PLGA) and SBF, in order to investigate whether and to what extent inorganic ionic composition of human blood plasma leads to the aforementioned changes in the material.

N-CP/PLGA was incubated for 1, 2, 3, and 5 weeks in SBF. The surface of the material was analyzed on SEM-EDS and FTIR spectrometer, while SBF was subjected to pH and electrical conductivity measurement.

Our results indicate that dissolution of the polymer component of the material N-CP/PLGA and precipitation of the material similar to hydroxyapatite on its surface are based on the morphologic changes seen in this material.

The mechanism of the apatite formation on the bioceramic surface was intensively studied and was considered crucial in designing the new biomaterials. The results obtained in this work indicate that N-CP/PLGA may be a good candidate for application to bone regeneration.

To develop a marker set for simultaneously assessing upper and lower limb biomechanics during gait.

24 healthy young subjects (mean age: 23.80 years) were assessed quantitatively using an optoelectronic system, two force platform and a video system. Passive markers were positioned according to the proposed marker set which enables acquiring the upper and lower limb movement simultaneously during Gait Analysis. In addition to the traditional parameters obtained from Gait Analysis, the shoulder and elbow angles were computed from markers coordinates of upper limbs; then, some significant parameters were identified and calculated. From shoulder and elbow position, angles, angular velocities, angular acceleration, moments, and powers were calculated for shoulder and elbow joints.

Kinematic and kinetic data were obtained in the three planes (sagittal, frontal, and transversal) for the shoulder and in the sagittal plane for the elbow. Normative ranges were obtained for these parameters from data of healthy participants.

The proposed experimental set-up enables simultaneous assessment of upper and lower limb movement during gait. Thus, no further trials are required in addition to those acquired during standard gait analysis in order to assess upper limb motion, which also makes the experimental set-up feasible for clinical applications.

Coupling the potential for bone regeneration and the ability for in situ controlled drug release in a single device is a challenging field of research in bone tissue engineering; in an attempt to pursue this aim, mesoporous bioactive glass (MBG) membranes belonging to the SiO₂-P₂O₅-CaO ternary system were produced and characterized.

The glass was synthesized via a sol-gel route coupled with an evaporation-induced self-assembly process by using a non-ionic block co-polymer as a mesostructure former. MBG structure and morphology, as well as mesopores size and shape, were investigated by x-ray diffraction, transmission electron microscopy, and N₂ adsorption-desorption measurements. In vitro bioactivity was investigated by soaking MBG membranes in simulated body fluid (SBF) for different time frames. Ibuprofen was encapsulated into MBG pores and drug release kinetics in SBF were assessed. Biological tests by using SAOS-2 cells were performed to assess the material cytocompatibility.

The material revealed significant ability to induce hydroxyapatite formation on its surface (bioactivity). Drug release kinetics in SBF are very similar to those obtained for mesoporous silica having mesopore size comparable to that of the prepared MBG (~5 nm). No evidence of cell viability depression was detected during in vitro culture, which demonstrates the good biological compatibility of the material.

The easiness of tailoring and shaping, the highly bioactive and biocompatible behavior, and the drug uptake/release ability of the prepared materials may suggest their use as “smart” multifunctional grafts for bone reconstructive surgery.

The effective results shown in the porous systems of tantalum employed for the use of osseointegrates has been demonstrated by means of animal experimentation. However, there is a total lack of any research studies on the osseointegration of tantalum implants from retrieval of the same after a period of time whereby the material had been implanted within the human body.

For this study, five rod implants used for the treatment of avascular necrosis of the femoral head were retrieved following collapse of the femoral head and conversion to total hip arthroplasty. The time of implantation ranged between six weeks and twenty months.

Observation during this study has confirmed the effectiveness of osseointegration within this period of time. New bone was observed around and within the porous system of the on rod devices at retrieval date. The bone ingrowth, however, proved to be slower and less intense than that resulting within animal species during the first few months after implantation.

The results obtained in the quantitative assessment of this process proved to be similar to those results achieved by other authors in previous experimental work studies.

Microwave and water bath postpolymerization have been suggested as methods to improve the mechanical properties of heat and autopolymerizing acrylic resins. However, the effects of autoclave heating on the fracture properties of autopolymerizing acrylic resins have not been investigated.

The aim of this study was to assess the effectiveness of various autoclave postpolymerization methods on the fracture properties of 3 different autopolymerizing acrylic resins.

Forty-two specimens of 3 different autopolymerizing acrylic resins (Orthocryl, Paladent RR and Futurajet) were fabricated (40×8×4mm), and each group was further divided into 6 subgroups (n=7). Control group specimens remained as processed (Group 1). The first test group was postpolymerized in a cassette autoclave at 135°C for 6 minutes and the other groups were postpolymerized in a conventional autoclave at 130°C using different time settings (5, 10, 20 or 30 minutes). Fracture toughness was then measured with a three-point bending test. Data were analyzed by ANOVA followed by the Duncan test (α=0.05).

The fracture toughness of Orthocryl and Paladent-RR acrylic resins significantly increased following conventional autoclave postpolymerization at 130°C for 10 minutes (P<.05). However, the fracture toughness of autoclave postpolymerized Futurajet was not significantly different than its control specimens (P<.05). The fracture toughness of Futurajet was significantly less than Paladent RR and Orthocryl specimens when autoclaved at 130°C for 10 minutes.

Within the limitations of this study, it can be suggested that autoclave postpolymerization is an effective method for increasing the fracture toughness of tested autoploymerized acrylic resins.

This paper compares the interaction between the nanomaterial containing calcium phosphate/poly-DL-lactide-co-glycolide (N-CP/PLGA) and SBF, in order to investigate whether and to what extent inorganic ionic composition of human blood plasma leads to the aforementioned changes in the material.

N-CP/PLGA was incubated for 1, 2, 3, and 5 weeks in SBF. The surface of the material was analyzed on SEM-EDS and FTIR spectrometer, while SBF was subjected to pH and electrical conductivity measurement.

Our results indicate that dissolution of the polymer component of the material N-CP/PLGA and precipitation of the material similar to hydroxyapatite on its surface are based on the morphologic changes seen in this material.

The mechanism of the apatite formation on the bioceramic surface was intensively studied and was considered crucial in designing the new biomaterials. The results obtained in this work indicate that N-CP/PLGA may be a good candidate for application to bone regeneration.

The main aim of the present study is to develop a marker set for simultaneously assessing upper and lower limb biomechanics during gait.

24 healthy young subjects (mean age: 23.80 years) were assessed quantitatively using an optoelectronic system, two force platform and a video system. Passive markers were positioned according to the proposed marker set which enables acquiring the upper and lower limb movement simultaneously during Gait Analysis. In addition to the traditional parameters obtained from Gait Analysis, the shoulder and elbow angles were computed from markers coordinates of upper limbs; then, some significant parameters were identified and calculated. From shoulder and elbow position, angles, angular velocities, angular acceleration, moments, and powers were calculated for shoulder and elbow joints.

Kinematic and kinetic data were obtained in the three planes (sagittal, frontal, and transversal) for the shoulder and in the sagittal plane for the elbow. Normative ranges were obtained for these parameters from data of healthy participants.

The proposed experimental set-up enables simultaneous assessment of upper and lower limb movement during gait. Thus, no further trials are required in addition to those acquired during standard gait analysis in order to assess upper limb motion, which also makes the experimental set-up feasible for clinical applications.