Which of the following substances would be used for cauterizing small oral lesions?

Silver nitrate is commonly used for cauterizing small oral lesions due to its properties as a chemical cauterizer. It functions by causing coagulation of proteins in the tissue upon contact, which helps to stop bleeding and promote healing in small lesions. The application of silver nitrate can effectively reduce discomfort and expedite recovery in oral lesions, making it a preferred choice in clinical practice.

Sodium bicarbonate is primarily used as an antacid or to neutralize stomach acid, while hydrogen peroxide is more commonly used as a disinfectant or antiseptic rather than a cauterizing agent. Lidocaine, on the other hand, is a local anesthetic used to numb tissues but does not possess cauterizing properties. Thus, silver nitrate stands out as the most effective option for the specific purpose of cauterization in oral lesions.