The surface measures of machined titanium alloys as dental materials can be enhanced by adopting a decision-making algorithm in the machining process. The surface quality is normally characterized by more than one quality parameter. Hence, it is very important to establish multi-criteria decision making to compute the optimal process factors. In the present study, Taguchi–Grey analysis-based criteria decision making has been applied to the input process factors in the wire EDM (electric discharge machining) process. The recast layer thickness, wire wear ratio and micro hardness have been chosen to evaluate the quality measures. It was found that the wire electrode selection was the most influential factor on the quality measures in the WEDM process, due to its significance in creating spark energy. The optimal arrangement of the input process parameters has been found using the proposed approach as gap voltage (70 V), discharge current (15 A) and duty factor (0.6). It was proved that the proposed method can enhance the efficacy of the process. Utilizing the computed combination of optimal process parameters in surface quality analysis has significantly contributed to improving the quality of machining surface.
Regeneration and reconstruction of segmental bone defects (SBD) is a clinical challenge in maxillofacial surgery and orthopedics. The present study evaluated efficacy of guided bone-regeneration (GBR) of rat femoral SBD using osteoconductive equine-bone (EB) and beta-tricalcium phosphate (beta-TCP) grafts, either with or without platelet-derived growth-factor (PDGF). Following ethical-approval, 50 male Wistar-Albino rats (aged ~12–15 months and weighing ~450–500 g) were included. A 5 mm femoral critical-size SBD was created and animals were divided into five groups depending on the graft material used for GBR (EB, EB + PDGF, Autograft, beta-TCP, beta-TCP + PDGF; n = 10/group). Following 12-weeks of healing, animals were sacrificed and femur specimens were analyzed through qualitative histology and quantitative histomorphometry. There was new bone bridging femoral SBD in all groups and qualitatively, better bone formation was seen in autograft and EB + PDGF groups. Histomorphometric bone-area (BA %) was significantly high in autograft group, followed by EB + PDGF, beta-TCP + PDGF, EB, and beta-TCP groups. Addition of PDGF to EB and beta-TCP during GBR resulted in significantly higher BA%. After 12-weeks of healing, EB + PDGF for GBR of rat femoral segmental defects resulted in new bone formation similar to that of autograft. Based on this study, GBR with EB and adjunct PDGF could be a potential clinical alternative for reconstruction and regeneration of segmental bone defects.
Purpose: Considering the important role of oral and maxillofacial surgeons in healthcare services and the stressful nature of their job, this study aimed to assess the occupational stress among oral and maxillofacial surgeons and residents in Saudi Arabia. Materials and Methods: Cross-sectional questionnaires were developed, and they included the perceived stress scale and questions about potential sources of stress. A sample size of 180 was determined using a 0.05 level of significance and a precision of ±8%. The survey was distributed using a consecutive non-random sampling method to all oral and maxillofacial surgeons and residents in all regions in Saudi Arabia from May to December 2019. Results: One hundred and seventy-two responses were received. Males were the predominant gender. The perceived stress scale revealed a moderate stress level among surgeons and residents. However, residents had a significantly higher score (P = 0.005). Increased working days were significantly associated with higher stress levels (P = 0.006). Long on-call periods were significantly and positively correlated with increased stress levels among residents since their work schedule was not flexible (P = 0.000). The majority of surgeons and residents believe that they have unconducive and stressful work environments and that working as a maxillofacial surgeon is stressful. Conclusion: The study results suggest that there is increased occupational stress among oral and maxillofacial surgeons and residents in Saudi Arabia. This study highlights the need for stress management programs to minimize stress factors at the workplace and to ensure a healthy working environment for the practitioners.
The current work reports the biosynthesis of silver nanoparticles (AgNPs) using the antimicrobial activities of ethyl acetate extract of Urtica diocia (UD) leaves as a reducing and capping agent. The synthesized UD-AgNPs were characterized using UV–visible spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray analysis (EDAX), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and dynamic light scattering (DLS). The UD-AgNPs were evaluated against Gram-positive and Gram-negative bacteria, and their size, shape, and distribution were recorded. The average size of an NP was 19.401 nm. The zone of inhibition (ZOI) for 75 µL of UD-AgNPs against Pseudomonas aeruginosa (P. aeruginosa) was 21 ± 0.4 mm more than that of the control drug Ciprofloxacin (16 ± 10 mm). The minimum inhibitory concentration (MIC) was the lowest against Escherichia coli (E. coli) (36 ± 3 µg/mL) and Staphylococcusepidermidis (S. epidermidis) (38 ± 3 µg/mL). Moreover, the minimum bactericidal concentration (MBC) was the lowest against E.coli (75 ± 00 µg/mL) and Enterococcus faecalis (E. faecalis (83 ± 16 µg/mL). Thus, the UD-AgNPs synthesized using the ethyl acetate extract of UD can be used as a new antimicrobial drug.
The development of alternatives to vascular bone grafts, the current clinical standard for the surgical repair of large segmental bone defects still today represents an unmet medical need. The subcutaneous formation of transplantable bone has been successfully achieved in scaffolds axially perfused by an arteriovenous loop (AVL) and seeded with bone marrow stromal cells or loaded with inductive proteins. Although demonstrating clinical potential, AVL‐based approaches involve complex microsurgical techniques and thus are not in widespread use. In this study, 3D‐printed microporous bioceramics, loaded with autologous total bone marrow obtained by needle aspiration, are placed around and next to an unoperated femoral vein for 8 weeks to assess the effect of a central flow‐through vein on bone formation from marrow in a subcutaneous site. A greater volume of new bone tissue is observed in scaffolds perfused by a central vein compared with the nonperfused negative control. These analyses are confirmed and supplemented by calcified and decalcified histology. This is highly significant as it indicates that transplantable vascularized bone can be grown using dispensable vein and marrow tissue only. This is the first report illustrating the capacity of an intrinsic vascularization by a single vein to support ectopic bone formation from untreated marrow.
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