One of the most commonly faced clinical problems is dentinal hypersensitivity (DH).It's a "enigma" that's "often met yet seldom comprehended." It is defined as a sensation of discomfort caused by exposed dentine in response to heat, chemical, tactile, or osmotic stimulation. It appears to be a common ailment, with estimates ranging from 4% to 74 percent of the population.The study aimed in evaluating the efficacy of sodium fluoride varnish, dentine bonding agent and diode laser in treating dentine hypersensitivity in vitro and in vivo.The research was split into two parts: in vitro and in vivo. In the in vitro study, 40 anterior teeth were extracted and separated into four groups: control, group A (fluoride varnish), group B (dentine bonding agent), and group C (laser), all of which were studied under a scanning electron microscope. For the in vivo part 30 patients aged 20-50 years with the chief complaint of sensitivity to hot and cold were selected from the outpatient department (OPD) of Seema Dental college and Hospital. The patients were divided into 3 groups, group A(fluoride varnish), group B (dentine bonding agent) group C (laser).At the end of 3 months, there was a statistically significant difference seen in mean VAS and VRS scores between Group A, Group B, and Group C; additionally, the mean of dentinal tubules in the SEM study (In vitro) was seen to be significantly higher in the Control group compared to Group A and Group B, and significantly higher than Group C.According to the findings of this study, all three treatment methods, sodium fluoride varnish, dentine bonding agent and laser are efficient in reducing dentine hypersensitivity in both in vivo and vitro studies, with laser showing better outcomes.

High generation of aerosols, and the presence of SARS-CoV-2 in saliva have suggested oral cavity as a reservoir for COVID-19 transmission. COVID-19 can penetrate the human body. The transmission can occur during coughing, sneezing, talking and even during dental care. SARS-CoV-2 is an enveloped virus, characterized by an outer lipid membrane. It has been seen that preprocedural rinses with mouthwash reduces the viral load. Chlorhexidine gluconate has been used in the clinical practice since ages. It is a broad spectrum antimicrobial agent, causing distruction of cellular membranes. It acts against gram positive and gram negative bacteria, aerobes, facultative anaerobes and fungus. It is also seen to be effective against viruses. Therefore, this review focuses on the role of chlorhexidine in COVID-19.