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.
1 October 2020 in Advances in Medical Education and Practice
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.
Carob-mediated calcium hydroxide nanoparticles (C-CaOH2 NPs) are a type of NPs, newly developed via a green synthesis method, that have demonstrated good in vitro biocompatibility. However, their antibacterial potential has not yet been explored. Both calcium hydroxide and carob are known for their antibacterial potency as bulk materials; thus, we hypothesized that C-CaOH2 NPs may exhibit promising antibacterial efficacy. This study aimed to examine the antibacterial activity of C-CaOH2 NPs against aerobic and anaerobic strains using zone of inhibition (ZOI), minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) tests. The results showed that the Gram-negative aerobic strains are more susceptible than the Gram-positive stains. The most susceptible bacteria were P. aeruginosa, E. coli, and S. aureus, in that order. Conversely, P. micra and E. faecalis were the least susceptible strains. The best recorded ZOIs were at 100 and 150 mg/mL concentrations in all bacteria, with the greatest diameter (11.7 ± 0.6 mm) exhibited in P. aeruginosa. Moreover, the MICs for aerobes were 3.12 mg/mL, except for E. faecalis (0.78 mg/mL) and K. pneumoniae (1.56 mg/mL). MBCs were 12.5 mg/mL for all except P. aeruginosa (3.12 mg/mL) and K. pneumoniae (6.25 mg/mL). The anaerobic strain P. micra exhibited the highest values for both MIC (15.62 mg/mL) and MBC (31.25 mg/mL). The current investigation revealed that C-CaOH2 NPs have intermediate and dose-dependent antibacterial activity that may have variable biomedical applications.
Purpose: The purpose of this paper is to demonstrate the route to digitize the customized mandible implants consisting of image acquisition, processing, implant design, fitting rehearsal and fabrication using fused deposition modeling and electron beam melting methodologies. Design/methodology/approach: Recent advances in the field of rapid prototyping, reverse engineering, medical imaging and image processing have led to new heights in the medical applications of additive manufacturing (AM). AM has gained a lot of attention and interest during recent years because of its high potential in medical fields. Findings: Produced mandible implants using casting, milling and machining are of standard sizes and shapes. As each person’s physique and anatomical bone structure are unique, these commercially produced standard implants are manually bent before surgery using trial and error methodology to custom fit the patient’s jaw. Any mismatch between the actual bone and the implant results in implant failure and psychological stress and pain to the patient. Originality/value: The novelty in this paper is the construction of the customized mandibular implant from the computed tomography (CT) scan which includes surface reconstruction, implant design with validation and simulation of the mechanical behavior of the design implant using finite element analysis (FEA). There has been few research studies on the design and customization of the implants before surgery, but there had been hardly any study related to customized design implant and evaluating the biomechanical response on the newly designed implant using FEA. Though few studies are related to FEA on the reconstruction plates, but their paper lacks the implant design model and the reconstruction model. In this research study, an integrated framework is developed for the implant design, right from the CT scan of the patient including the softwares involved through out in the study and then performing the biomechanical study on the customized design implant to prove that the designed implant can withstand the biting and loading conditions. The proposed research methodology which includes the interactions between medical practitioners and the implant design engineers can be incorporated to any other reconstruction bone surgeries.
Due to the high prevalence of oral and maxillofacial (OMF) trauma in city of Riyadh, a special focus on pediatric trauma is needed. The purpose of this audit was to assess the protocol followed by the OMF unit at King Khalid University Hospital (KKUH) on pediatric trauma patients. The trauma incidence, mechanism of injury, volume, the type of pediatric trauma operated and dental management were analyzed. A quantitative retrospective review of 223 patients, at pediatric emergency unit of KKUH, Riyadh, KSA from January 2017 to July 2018, was done. The data retrieved included variables such as, age, gender, and cause of injury, site of injury, type of injury, and assessment of jaws, and teeth. Data regarding the type of investigations, treatment protocol, follow up visit, and dental management, were extracted from the medical records. Of the 223 pediatric patients presenting to the emergency unit, 116 (52%) were under the age of 5 years. A total of 64.4% of patients reported “self-fall” as the cause of injury. Soft-tissue injuries were common in 63 (56.8%) of patients in the form of lacerations 87 (41.2%). Involvement of the teeth in the injury was observed in 57 patients, in which 33 (57.9%) patients were reported to have tooth/teeth avulsions, 15 (26.3%) patients had luxation and 9 (15.8%) patients had crown fractures. 27 (47%) patients were referred to the pedodontist for a follow-up visit. It can concluded that clinicians facing maxillofacial trauma in an emergency department need to have access to useful and practice guidelines. The study also showed the need for more manpower-oriented training such as a pedodontist and a general dentist to join the OMFS team to manage pediatric patients. The regional referral hospitals should be equipped to decentralize the management of these patients to the Dental University Hospital.
15 November 2018 in Journal of Investigative Surgery
Background and Objectives: Beta-tricalcium phosphate (beta-TCP) has been used for bone regeneration. The objective of this study was to assess longitudinally, the regeneration of critical sized segmental defects (CSSD) in rat femur using beta-TCP with or without recombinant platelet-derived growth factor (PDGF) through in vivo micro-computed tomography (micro-CT). Materials and Methods: Following ethical approval unilateral femoral CSSD measuring 5 mm was surgically created, under general anesthesia, in 30 male Wistar-Albino rats (aged 12–18 months; weighing 450–500 g). CSSD was stabilized using titanium mini-plate (4 holes, 1.0 mm thick with 8 mm bar). Depending upon biomaterial used for regeneration, the animals were randomly divided into: Control group (N = 10): CSSD covered with resorbable collagen membrane (RCM) only; Beta-TCP group (N = 10): CSSD filled with beta-TCP and covered by RCM; Beta-TCP + PDGF group (N = 10): CSSD filled with beta-TCP soaked in recombinant PDGF and covered by RCM. Longitudinal in vivo micro-CT analysis of the CSSD was done postoperatively at baseline, 2nd, 4th, 6th, and 8th weeks to assess volume and mineral density of newly formed bone (NFB) and beta-TCP. Results: Significant increase in NFB volume (NFBV) and mineral density (NFBMD) were observed from baseline to 8-weeks in all groups. Based on longitudinal in vivo micro-CT at 8-weeks, beta-TCP + PDGF group had significantly higher (p < 0.01) NFBV (38.98 ± 7.36 mm3) and NFBMD (3.72 ± 0.32 g/mm3) than the beta-TCP (NFBV—31.15 ± 6.68 mm3; NFBMD—2.28 ± 0.86g/mm3) and control (NFBV: 5.60 ± 1.06 mm3; NFBMD: 0.27 ± 0.02 g/mm3) groups. Significantly, higher reduction in beta-TCP volume (TCPV) and mineral density (TCPMD) were 1 observed in the beta-TCP + PDGF group when compared to the beta-TCP group. Conclusion: Addition of recombinant PDGF to beta-TCP enhanced bone regeneration within rat femoral CSSD and increased resorption rates of beta-TCP particles.