Biomaterials Evaluation: Conceptual Refinements and Practical Reforms

Regarding the widespread and ever-increasing applications of biomaterials in different medical fields, their accurate assessment is of great importance. Hence the safety and efficacy of biomaterials is confirmed only through the evaluation process, the way it is done has direct effects on public health. Although every biomaterial undergoes rigorous premarket evaluation, the regulatory agencies receive a considerable number of complications and adverse event reports annually. The main factors that challenge the process of biomaterials evaluation are dissimilar regulations, asynchrony of biomaterials evaluation and biomaterials development, inherent biases of postmarketing data, and cost and timing issues. Several pieces of evidence indicate that current medical device regulations need to be improved so that they can be used more effectively in the evaluation of biomaterials. This article provides suggested conceptual refinements and practical reforms to increase the efficiency and effectiveness of the existing regulations. The main focus of the article is on strategies for evaluating biomaterials in US, and then in EU

A social work study on different factors influencing youth on hope for the future

In this paper, we present an empirical study to study the effects of religious duties, communicating with parents; leisure, media planning, city planning, socio-economic and education on different factors influencing the future of youth. The proposed study of this paper designs a questionnaire and distributes it among 400 people aged 18 to 29 and the results are investigated using Pearson correlation ratios. The results of our investigation indicate that there are some positive and meaningful relationship between religious duties and their hope for future (r=44%), a positive and meaningful relationship between leisure and hope for future (31%). In addition, there is a relatively positive and somewhat meaningful relationship between city planning and hope for future (15%) and finally, a small but positive relationship between media planning and hope for the future (6%). However, there is no evidence belief that there is any meaningful relationship between education and hope for the future

A social work study on relationship between transactional and laissez-fair leadership style and personality traits: A case study of educational system

Leadership style plays an essential role on personality trait in educational systems. In this paper, we present a study among 180 school principals in city of Khomeinishahr, located in province of Esfahan, Iran. The study selects a sample of 123 principals and examines ten hypotheses including the effects of personality trait neuroticism, extroversion, resilience, participative, conscientiousness on leadership style. The study examined the effects of two groups of leadership, namely transactional leadership and Laissez-fair leadership styles on five personality traits. The results have shown that there were some meaningful relationship between transactional leadership and personality trait extraversion, resilience, participative and consciousness but there was not meaningful relationship between transactional leadership and personality trait neuroticism. In addition, while there were meaningful and positive relationship between Laissez-fair leadership style and personality trait extraversion as well as being resilience, our survey did not find any meaningful relationship between Laissez-fair leadership style and personality trait neuroticism, extraversion and being consciousness

Efficacy of the Biomaterials 3 wt%-nanostrontium-hydroxyapatite-enhanced Calcium Phosphate Cement (nanoSr-CPC) and nanoSr-CPC-incorporated Simvastatin-loaded Poly(lactic-co-glycolic-acid) Microspheres in Osteogenesis Improvement

Aims The purpose of this multi-phase explorative in vivo animal/surgical and in vitro multi-test experimental study was to (1) create a 3 wt%-nanostrontium hydroxyapatite-enhanced calcium phosphate cement (Sr-HA/CPC) for increasing bone formation and (2) creating a simvastatin-loaded poly(lactic-co-glycolic acid) (SIM-loaded PLGA) microspheres plus CPC composite (SIM-loaded PLGA + nanostrontium-CPC). The third goal was the extensive assessment of multiple in vitro and in vivo characteristics of the above experimental explorative products in vitro and in vivo (animal and surgical studies). Methods and results pertaining to Sr-HA/CPC Physical and chemical properties of the prepared Sr-HA/CPC were evaluated. MTT assay and alkaline phosphatase activities, and radiological and histological examinations of Sr-HA/CPC, CPC and negative control were compared. X-ray diffraction (XRD) indicated that crystallinity of the prepared cement increased by increasing the powder-to-liquid ratio. Incorporation of Sr-HA into CPC increased MTT assay (biocompatibility) and ALP activity (P \u3c 0.05). Histomorphometry showed greater bone formation after 4 weeks, after implantation of Sr-HA/CPC in 10 rats compared to implantations of CPC or empty defects in the same rats (n = 30, ANOVA P \u3c 0.05). Methods and results pertaining to SIM-loaded PLGA microspheres + nanostrontium-CPC composite After SEM assessment, the produced composite of microspheres and enhanced CPC were implanted for 8 weeks in 10 rabbits, along with positive and negative controls, enhanced CPC, and enhanced CPC plus SIM (n = 50). In the control group, only a small amount of bone had been regenerated (localized at the boundary of the defect); whereas, other groups showed new bone formation within and around the materials. A significant difference was found in the osteogenesis induced by the groups sham control (16.96 ± 1.01), bone materials (32.28 ± 4.03), nanostrontium-CPC (24.84 ± 2.6), nanostrontium-CPC-simvastatin (40.12 ± 3.29), and SIM-loaded PLGA + nanostrontium-CPC (44.8 ± 6.45) (ANOVA P \u3c 0.001). All the pairwise comparisons were significant (Tukey P \u3c 0.01), except that of nanostrontium-CPC-simvastatin and SIM-loaded PLGA + nanostrontium-CPC. This confirmed the efficacy of the SIM-loaded PLGA + nanostrontium-CPC composite, and its superiority over all materials except SIM-containing nanostrontium-CPC

Preparation, Characterization and Evaluation of Drug Release Properties of Simvastatin-loaded PLGA Microspheres

Abstract Microspheres formulated from poly (D, L-lactic-co-glycolide) (PLGA), a biodegradable polymer, have been extensively evaluated as a drug delivery system. In this study, the preparation, characterization and drug release properties of the PLGA microspheres were evaluated. Simvastatin (SIM)-loaded PLGA microspheres were prepared by oil-in-water emulsion/solvent evaporation method. The microspheres were then frozen to −80 °C, they were freeze dried for 24 h. Characterization of SIM-loaded PLGA microspheres was evaluated by X-ray diffraction analysis, Fourier transform infrared spectroscopy analysis, and scanning electron microscopy (SEM). Drug release potential was evaluated by UV-spectrophotometry. The experimental results revealed that SIM-loaded PLGA microspheres can be successfully obtained through solvent evaporation method with appropriate morphologic characteristics and high encapsulation efficiency. The drug release pattern from polymeric microspheres in the phosphate buffered saline medium was measured during a 21-day period using UV-spectrophotometry. The correlation coefficient value (r 2 = 0.9878) of the trend lines of the graph showed that the SIM-loaded PLGA microspheres best fit with zero order release pattern. No burst release was observed with polymeric matrix. The drug release characteristic of the microspheres ascertained that the release was about 27% for SIM-loaded microspheres, which occurred within the first 6 days after maintaining the microspheres in phosphate buffer saline. Also, the microspheres successfully presented a slow release and the duration of the release lasted for more than 21 days. It can be concluded that SIM-loaded PLGA microspheres hold great promise for using as a drug-delivery system in biomedical applications, especially in drug delivery systems and tissue engineering

Psychometric Properties and Diagnostic Accuracy of the Edinburgh Postnatal Depression Scale in a Sample of Iranian Women

Background: Edinburgh Postnatal Depression Scale (EPDS) has been used as a reliable screening tool for postpartum depression in many countries. This study aimed to assess the psychometric properties and diagnostic accuracy of the EPDS in a sample of Iranian women.Methods: Using stratified sampling 262 postpartum women (2 weeks-3 months after delivery) were selected from urban and rural health center in the city of Isfahan. They were interviewed using EPDS and Hamilton depression rating scale (HDRS). Data were assessed using factor analysis, diagnosis analysis of receiver operating characteristic (ROC) curve, Cronbach's alpha and Pearson correlation coefficient.Results: The age of then participants ranged 18-45 years (26.6±5.1). Based on a cut-off point of >13 for HDRS, 18.3% of the participants. The overall reliability (Cronbach's alpha) of EPDS was 0.79. There was a significant correlation (r2=0.60, P value<0.01) between EPDS and HDRS. Two factor analysis showed that anhedonia and depression were two explanatory factors. At a cut-off point12 the sensitivity of the questionnaire was 78% (95% CI: 73%-83%) and its specificity was 75% (95% CI: 72%-78%). Conclusion: The Persian version of the EPDS showed appropriate psychometric properties diagnostic accuracy index. It can be used by health system professionals for detection, assessment and treatment for mothers with post partum depression

Challenges in Three-Dimensional Printing of Bone Substitutes

Hope is that tissue engineering will provide a solution to meet the growing needs for bone substitutes. Among the potential solutions, three-dimensional (3D) printing is a promising method to fabricate functional bone substitutes especially for treatment of complex and critical-sized bone defects. Despite its encouraging achievements, 3D printing of bone substitutes still faces serious challenges including mechanical strength, shape complexity, optimization of pore parameters, and vascularization. The newer approach, that is, 3D bioprinting, is also confronted with challenges, which have prevented the realization of the dream of fabricating functional patient-specific bone substitutes. This article reviews the major challenges toward 3D printing and bioprinting of bone substitutes and recent studies addressing them. Potential solutions for each challenge and future directions are also provided

The Response of the Pulp-Dentine Complex, PDL, and Bone to Three Calcium Silicate-Based Cements: A Histological Study in an Animal Rat Model

Objective. The aim of this study was to histologically examine the tissue reaction of three different calcium silicate cements in the closure of perforations in rat incisor teeth. Material and Methods. An experimental lateral root perforation with pulp exposure was performed in 32 lower incisors of 16 male Wistar albino rats. They were randomly assigned into three test groups (each including eight teeth) that were filled either by Biodentine (BD) or MicroMega mineral trioxide aggregate (MM-MTA) or EndoSequence root repair material putty (ESRRM putty), besides eight unperforated incisors from the other four rats (control group). The inflammatory response and healing process were evaluated histologically and scored after one and four weeks. Differences among groups were tested by Kruskal–Wallis tests at P≤0.05. Results. In the first week, BD produced more inflammatory response in the pulpal (score 3) than other materials (score 2). Only ESRRM putty showed odontoblast-like cells in 50%, 25% dentine-like deposit, 25% evidence of bone deposition in the drilling site (score 2), and minimum periodontal ligament (PDL) necrosis and disorganization (25%, score 2). After one month, all groups had healthy pulpal tissue, but 25% of ESRRM putty retained score 1 inflammatory response, and 50% of the BD case had an incomplete palisading odontoblast layer (score 3). A thick and regular dentine bridge deposition was seen in the ESRRM putty group in comparison with MM-MTA and BD cases. The cortical plate healing in all ESRRM putty samples was complete (score 3), while an incomplete closure was seen in MM-MTA and BD groups (score 2). Both the MM-MTA and ESRRM putty groups had fully organized PDL (score 2), while in 50% of BD cases, a necrotizing area and disorganized PDL with inflammatory cells infiltration were still present. Statistically significant differences in the scores of any histologic parameters among the three tested materials were observed neither in the 1st nor in the 4th weeks of the experimental period. Conclusion. Better tissue compatibility and repair of pulpal and periodontal tissue have been detected after lateral perforation in the root of rat incisors when treated with ESRRM putty than MM-MTA and BD. However, the difference was not significant

Bioactivity and Physicochemical Properties of Three Calcium Silicate-Based Cements: An In Vitro Study

Objective. This study evaluated the bioactivity and physicochemical properties of three commercial calcium silicate-based endodontic materials (MTA, EndoSequence Root Repair Material putty, and Biodentine™). Material and Methods. Horizontal sections of 3 mm thickness from 18 root canals of human teeth were subjected to biomechanical preparation with WaveOne Gold large rotary instruments. The twelve specimens were filled with three tested materials (MM-MTA, EndoSequence Root Repair Material putty, and Biodentine™) and immersed in phosphate-buffered saline for 7 and 30 days. After this period of time, each specimen of each material was processed for morphological observation, surface precipitates, and interfacial dentin using SEM. In addition, the surface morphology of the set materials, without soaking in phosphate-buffered solution after one day and after 28 days stored in phosphate-buffered saline, was evaluated using SEM; also, the pH of the soaking water and the amount of calcium ions released from the test materials were measured by using an inductively coupled plasma-optical emission spectroscopy test. Data obtained were analyzed using one-way analysis of variance and Tukey’s honest significant difference test with a significance level of 5%. Result. The formation of precipitates was observed on the surfaces of all materials at 1 week and increased substantially over time. Interfacial layers in some areas of the dentin-cement interface were found from one week of immersion. All the analyzed materials showed alkaline pH and capacity to release calcium ions; however, the concentrations of released calcium ions were significantly more in Biodentine and ESRRM putty than MM-MTA (P<0.05). ESRRM putty maintained a pH of around 11 after 28 days. Conclusion. Compared with MM-MTA, Biodentine and ESRRM putty showed significantly more calcium ion release. However, exposure of three tested cements to phosphate-buffered solution resulted in precipitation of apatite crystalline structures over both cement and dentin that increased over time. This suggests that the tested materials are bioactive

Psychometric Properties of the Cornell Scale for Depression in Dementia in Elderly Individuals with Dementia in Isfahan, Iran

Introduction: Depression is the second most prevalent psychological disorder in the elderly. This study was designed to evaluate the psychometric properties of the Cornell Scale for Depression in Dementia (CSDD) in the elderly population afflicted with dementia in Isfahan, Iran. Materials and Methods: This psychometric study was performed on 110 elderly individuals who were selected randomly from among individuals who were referred to the elderly clinic of Isfahan and were diagnosed as a case of dementia based on the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) criteria. All participants completed the CSDD, Mini-Mental State Examination (MMSE), and Geriatric Depression Scale (GDS). The collected data were analyzed descriptive statistics, Cronbach’s alpha, factor analysis, and the Pearson correlation coefficient in SPSS software. Results: Total scale reliability coefficient was 0.85 and the reliability of the factors of depression, psychotic depressive symptoms, sleep disorders, somatic symptoms, and anxiety was 0.77, 0.63, 0.79, 0.62, and 0.47, respectively. The correlation coefficient of GDS and MMSE with total scale of CSDD was obtained as 0.47 (P < 0.01) and 0.35 (P < 0.10), respectively, using the Pearson coefficient. Exploratory factor analysis showed that the 5 abovementioned extracted factors had common variance of 58.72%. Conclusion: The Persian version of CSDD contained acceptable psychometric properties in this sample of Iranian elderly individuals with dementia