The effect of location/site on polished human enamel after mechanical and chemical wear.

OBJECTIVE: To compare profilometry and microhardness of polished occlusal and buccal human enamel following a mechanical and chemical wear regime. METHODS: Enamel from polished human molars were sectioned into buccal and occlusal surfaces and randomly allocated into two groups (n = 10) and then exposed to 0.3 % citric acid at pH 2.7 for 10, 20, 40 and 60 mins each followed by abrasion with non-fluoridated toothpaste for 240 strokes in a reciprocating brushing machine. A white light profilometer with a spot size of 12 um measured mean step-height following each cycle. Microhardness indentations were conducted following the final cycled 60 mins erosion/abrasion using 0.01, 0.02, 0.1, 0.5 and 2.5 kgf indentation load. Statistical disparity were evaluated using a two-way ANOVA and post-hoc Sidak's multiple comparisons tests at α = 0.05. RESULTS: After erosion/abrasion, the mean (SD) step-heights on occlusal and buccal surfaces were not significantly different until 60 mins, when occlusal surfaces exhibited greater step-heights, 32.9 µm (2.8) and 31.1 µm (1.8) and p = 0.02, respectively. Buccal and occlusal microhardness was statistically lower following erosion/abrasion at loads of 0.01 kgf (p = 0.0005) and 0.02 kgf (p = 0.0006) but no significant differences were observed in the microhardness between the surfaces at any loads. CONCLUSION: The occlusal and buccal surfaces were not statistically different for microhardness or step height suggesting the susceptibility to wear is not related to the anatomy and structure of the tooth and is more likely related to other factors such as the environment. CLINICAL SIGNIFICANCE: The study emphasizes that a notable difference in wear between occlusal and buccal enamel surfaces emerges only after prolonged exposure to simultaneous chemical and mechanical stress. This finding necessitates a preventive dental approach that accounts for both the duration of exposure and environmental factors.

The Knowledge, Attitude, and Perception of Needlestick Injuries Among Dental Students in Riyadh, Kingdom of Saudi Arabia: A Cross-Sectional Survey.

INTRODUCTION: Needlestick injuries (NSIs) represent a significant source of bloodborne viruses in the healthcare sector, particularly in dentistry. Developing effective infection control programs necessitates access to surveillance data. A comprehensive evaluation, encompassing human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV), and serological testing, is crucial due to the potential lack of immediate symptoms in infected patients. It is essential to verify hepatitis B and tetanus immunization statuses and seek guidance from infectious disease experts for post-exposure prophylaxis. Aim and objective: This study aims to assess the knowledge, attitudes, and perceptions of NSIs among dentistry students in Riyadh, Saudi Arabia. METHODS: Conducted during the 2023-2024 academic year in Riyadh, Saudi Arabia, this cross-sectional study evaluated the knowledge, attitudes, and perceptions of undergraduate dental medicine students regarding NSIs. Ethical approval was obtained, and informed consent was meticulously collected. Before participation, potential subjects were furnished with a comprehensive information sheet outlining the study's purpose, the survey's nature, expected duration, and potential risks or benefits. The document emphasized their unequivocal right to withdraw from the study at any point without any adverse consequences. Data collection relied on an online survey administered to third and final-year dental students selected from specific universities. This selection criterion ensured that participants were directly relevant to the dental education context under investigation. Careful exclusions were made to minimize potential bias, particularly by excluding students from academic years other than the third and final years, thus maintaining a specific focus on this subgroup. Data analysis primarily compared NSI occurrences and awareness based on dental college and academic year. Detailed findings are presented in the results section. RESULTS: The study unveiled high vaccination rates (95.23%) and significant levels of education regarding bloodborne infections (81.38%) among participants. However, it was noteworthy that 72.72% believed their vaccinations offered complete protection. Only 47.18% believed that wearing surgical gloves reduced the risk of NSIs, while a substantial majority (93.07%) opposed the practice of needle recapping. Moreover, 76.19% demonstrated knowledge of post-exposure prophylaxis, indicating room for improvement in healthcare safety practices. Statistical analysis identified significant associations between the Dental College attended and both NSI occurrence (χ²=12.164, p=0.058) and awareness (χ²=14.629, p=0.023). Conversely, the academic year exhibited no significant relationship with either NSI occurrence (χ²=1.2, p=0.55) or awareness (χ²=0.44, p=0.8). Additionally, the study revealed non-normal distributions for both NSI occurrence (p<0.001) and awareness (p<0.001) among participants. CONCLUSION: In conclusion, this study underscores the pivotal role of awareness in mitigating NSI occurrences among dental students. Irrespective of their academic year, heightened awareness significantly correlated with reduced NSI incidence. These findings bear significant implications for dental education and practice, emphasizing the imperative need for comprehensive education and awareness initiatives to bolster healthcare safety among dental professionals.