is an emerging and rapidly-evolving situation. This study aimed to measure the level of knowledge and attitude of the Iranian dental students towards COVID-19 and its infection control strategies. This cross-sectional study was designed using a web-based method. The questionnaire associated with COVID-19 was sent to all Iranian students in the clinical course. The extracted data regarding the knowledge and attitude of the students were statistically analyzed. In this study, 531 dental students of the clinical course in 32 Iranian universities were included. The mean age of the participants was 23.13 ± 2.29 years. The average percentage of knowledge and attitude scores were 59.7% (moderate) and 66.0% (neutral), respectively. The association between the attitude of the students and their semesters was statistically significant (r = 0.183, p < 0.001). The age of the students was also significantly associated with their attitudes (r = 0.150, p = 0.001). The outbreak of COVID-19 might resurge due to re-opening of the dental faculties. Training courses on COVID-19 infection prevention strategies should be held for dental students, especially the junior ones, and the guidelines should be sent to all of them.

Background: Complications following impacted third molar surgery significantly affect patients' quality of life during the immediate postoperative period. This study aimed to achieve the proper anesthesia method by comparing the effect of the application of lidocaine alone with the application of lidocaine and articaine simultaneously in reducing the complications during and following impacted mandibular third molar surgery. Methods: The study design was a split-mouth double-blind randomized clinical trial. The study was conducted on 13 patients (26 samples) referred for elective surgical removal of bilateral impacted mandibular third molar with similar difficulty on both sides. Each patient underwent similar surgical procedures on two separate appointments. Each patient randomly received 2% lidocaine for conventional inferior alveolar nerve block and 4% articaine for local infiltration before the surgery on one side (group A) and 2% lidocaine alone (for both block anesthesia and infiltration) before the surgery on the other side (group B). Intraoperative and postoperative variables for both groups were established and statistically analyzed. Results: The findings showed that pain on the first day after surgery in group A was significantly lower than that in group B. The patients in group A mentioned experiencing less discomfort following the surgery. The increased horizontal swelling on the first and third days following surgery and oblique swelling on the seventh day in patients in group B were statistically significant. Conclusion: Choosing an appropriate anesthetic drug for oral surgery, specifically impacted third molar surgery, is dependent on the clinician's opinion, however; it seems that the combination of lidocaine and articaine may control the patient's pain significantly better than lidocaine alone.

Mandatory perquisites of successful root canal therapy are comprehensive knowledge about anatomy and morphology of teeth, cleaning and shaping of all canal system and sealing it off. This paper reports retreatment of three mandibular anterior teeth having two separate canals and two foramina with a six-month follow up.