Background and Aim: Oral lichen planus (OLP) is a chronic, inflammatory, T-cellmediated autoimmune oral mucosal disease. Oral lichenoid lesions develop as a type IV hypersensitivity reaction. Both of these entities are potential precancerous conditions; this adds to their clinical significance. The purpose of this literature review was to detect the similarities and the differences of these lesions to enhance the information of colleagues in managing these groups of patients. Materials and Methods: For this review, we searched Cochrane, Medline, and Embase databases from January 1990 to the end of October 2018. A total of 96 published papers, including review papers, case reports, cohort studies, case-control studies, and meta-analysis studies, were included and analyzed. Results: OLP and oral lichenoid reactions are two distinct diseases. They can be clinically similar but they have different etiologic factors. A histopathological study is necessary to differentiate them. Conclusion: The definitive diagnosis of these conditions is extremely important given their potentially premalignant nature. A timely diagnosis probably results in proper management. Based on the present research, the final differentiation between OLP and oral Lichenoid reactions relies on both clinical and histopathological manifestations according to the modified World Health Organization (WHO) criteria.

Background Oral lichen planus (OLP) is a common, chronic immunological and inflammatory condition. Many of the OLP patients complain of xerostomia. The M3 muscarinic cholinergic receptors (MR3) are the main receptors in the salivary glands responsible for water secretion into the saliva. This study aimed to assess the level of M3 muscarinic cholinergic receptors in minor salivary glands of OLP patients. Methods This case‐control cross‐sectional study evaluated 40 OLP patients and 22 controls. All participants completed two questionnaires (xerostomia and xerostomia inventory). Stimulated and unstimulated saliva samples were collected. The saliva flow rate was calculated by dividing the saliva volume (in milliliters) by time (in minutes). Six minor salivary glands were also surgically removed from the lower lip of patients and controls, and weighed using a digital scale with 10−4 g accuracy. They were then frozen at −80°C, and the level of M3 receptors of the glands was determined using the ELISA kit. Results The unstimulated and stimulated saliva flow rate was significantly lower in OLP patients. The xerostomia inventory score was significantly higher in the OLP group. The level of M3 muscarinic receptors in minor salivary glands of OLP patients was significantly higher than that in controls. Conclusions It may be concluded that the reduction in saliva flow significantly increases the number of M3 receptors in an attempt to compensate for this shortage and prevent xerostomia (compensatory upregulation).

Background: The emergence of coronavirus disease 2019 (COVID-19) pandemic had a significant impact on dental profession, and COVID-19 prevention and control have been the topic of numerous investigations. Objectives: This study aimed to review and present the most effective strategies for prevention and control of COVID-19 before, during, and after dental procedures in the pandemic and post-pandemic era. Materials and methods: This scoping review was conducted according to the five stages of conduct proposed by Arksey and O’Malley. The latest findings available in most accredited databases and scientific websites including Science Direct, Scopus, PubMed, and Google Scholar, and the guidelines recommended by the World Health Organization and Center for Disease Control and Prevention were searched using the following MeSH terms: “COVID-19”, “Dentistry”, “Infection Control”, and “SARS-CoV-2”. Irrelevant articles, duplicates, and those not meeting the eligibility criteria were excluded. The remaining 24 eligible articles were reviewed. Results: After data analysis, an efficient protocol for dental procedures during the COVID-19 pandemic was tabulated, which included emergency treatments only, preoperative rinsing of an effective mouthwash, patient triage, principles of personal protection for patients and the staff, aerosol elimination from the office, efficient disinfection of the environment, and specific measures for different dental procedures. Conclusion: Dental clinicians can play a pivotal role in prevention of COVID-19 transmission by precise adherence to the protocols, updating their knowledge, and educating patients prior to their visit. Accordingly, they can fulfill their professional responsibility in treatment of emergency cases and other patients. Despite the ongoing global vaccinations against the COVID-19, genetic mutations that occur in the viral genome over time can still challenge the future of dental profession.

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