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Purpose: The objective of this work is to study galvanic corrosion of different couples of prosthetic and implant alloys through the realization of a systematic review. Materials and Methods: An electronic search was performed on Pubmed, Google Scholar, Scopus, ScienceDirect, EbscoHost, and Web of Science for published studies related to electrogalvanism in oral implantology. The keywords used were "dental implants" and "galvanic corrosion." Two independent readers read the scientific articles. Results: From 65 articles initially identified, only 19 articles met the eligibility criteria. The evaluation of the selected articles allowed us to determine the parameters compared, such as the resistance to galvanic corrosion, the influence of fluorine and pH on the electrochemical behavior, and the release of metal ions and their cytotoxicity. Indeed, Ti6Al4V and precious alloys coupled to titanium were found to be the most resistant to galvanic corrosion, followed by cobalt-chromium alloys and nickel-chromium alloys which were least resistant. This resistance decreases with increasing fluorine concentration and with decreasing pH of the environment. Discussion. The implant-prosthetic system's galvanic resistance is influenced by many intrinsic factors: alloy composition and surface condition, as well as extrinsic factors such as pH variations and amount of fluorine. The effects of oral electrogalvanism are essentially the result of two main criteria: effects due to electric currents generated by corrosion and effects due to the release of metal ions by corrosion. Conclusion: To avoid this phenomenon, it is wise to follow the proposed recommendations such as the use of the minimum of distinct metals as much as possible, favoring the commercially pure titanium implant of Ti6Al4V, opting for the choice of couples, titanium/titanium, favoring daily mouthwashes of 227 ppm of fluoride, and avoiding fluorinated acid solutions.
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Introduction: The technology-enhanced learning and simulation-based learning are critically important pedagogic tools. They allow students to perfect their preclinical training by improving their skills and their manual dexterity while facilitating the acquisition of the know-how necessary for reproduction more realistically and faithfully of the behaviors required for a better dental practice. Retention is one of the mechanical fundamental principles of preparation of cemented fixed prostheses. It depends on several factors including the convergence of the axial walls. The undercut must be sparing in the reduction of tissue volume to obtain a low degree of convergence and a sufficient height of the preparation to comply with the retention and stabilization requirements of the prosthetic element. A draft value of 6° was recommended initially, but a range extending up to 16° has been accepted according to Weed et al. and Dodge et al., as being clinically achievable while providing good retention. Are students able to reproduce, in preclinical, total occlusal convergence (TOC) angles recommended on typodont and simulator? Objective: The evaluation of the TOC of the preparations made on typodont and simulator by the students in the 3rd year of the Faculty of Dental Medicine of Casablanca (FDMC). Material and Methods. A total of 140 dental preparations for cast crowns and metal-ceramics made by thirty-five 3rd year FDMC students were scanned by using the IDENTICA HYBRID optical scanner. The STL files were read by the 3D-TOOL-FREE software, two images were extracted for each preparation using the screen capture tool, and the two mediodistal (MD) and buccolingual angles (BL) were measured by the MB-RULER software. The statistical data were analyzed using the SPSS, software and comparisons were made by Student's t-test. Results: An overall average of 11.99° ± 4.48 was recorded for the preparations on the typodont with 11.40° ± 5.09 in the MD direction and 12.58° ± 4.74 in the BL direction. Concerning the simulator preparations, we recorded an overall average of 11.31° ± 4.16 with 10.81° ± 4.29 in the MD direction and 11.80° ± 5.44 in the BL direction. No significant difference was observed when comparing the preparations made on the typodont and the simulator. A percentage of 68.6% and 74.3% of the preparations made on the typodont and the simulators respectively fall within an acceptable range of 6 to 16°. Discussion. The TOC values achieved by the majority of students correspond to the recommended values which are 6 to 16° on average. The results of the simulator preparations are similar to the results of Marghalani for dental students at King Abdulaziz University, and Tiu et al., at the University of Otago in New Zealand. Conclusion: This study highlighted the difference between what is taught in dental schools, which is theoretically possible, and the academic results of actual practice. The generally recommended 6° tapers have proven difficult to achieve for many dental students. A margin of 6° to 16° of TOC angle is clinically achievable and allows sufficient retention. We can retain that most of the sample of our study had values that fall within the recommended range.
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INTRODUCTION: Practical activities in dentistry are characterized by a high noise level that can have adverse effects on the hearing health of professors, students, and teaching staff. The objective of our study was to make an assessment of the noise level during the practical fixed prosthodontics activities in the Faculty of Dentistry of Casablanca. MATERIALS AND METHODS: We conducted a descriptive cross-sectional study to measure the noise level in the practical room of fixed prosthodontics. The measurements were obtained during 4 sessions over a duration of 2 hours and 30 minutes, each with the use of a SdB + sound level meter at 4 different locations. RESULTS: The results showed the following: an average value of 69.35 dB (A) for the first practical session (south), an average value of 71.07 dB (A) for the 2nd practical session (east), an average value of 70.36 dB (A) for the 3rd practical session (west), and an average value of 72.06 dB (A) for the 4th practical session (center of the room). Discussion and Conclusion. The results obtained are similar to the results found in previous studies in other countries. These results are below the thresholds of the legislation and international standards. However, we have recorded punctual peaks that exceed the recommended level, requiring the introduction of the means of prevention and the measures of safety against the noise as well at the level of the practical activity classroom and the realization of more in-depth studies concerning the evaluation of the daily exposure of the professors, students, and teaching staff to noise.