Potassium nitrate: An effective treatment for pulpitis

Abstract

T he pulpitis induced by deep caries and exposure of the pulpal tissue to the microorganisms of the oral environment is currently treated by endodontic means or by removal of carious dentin and capping or sealing of the pulp so that the inflammation may be resolved and the pulp return to normal.‘~* Endodontic therapy is effective in restoring the health of the tooth, but this entails total removal of pulp down to the apices of the root canals and subsequent sealing of the apical region and filling of the root canal and pulp chamber with inert material. The relative vitality of the tooth is maintained by the vasculature of the periodontal membrane, but occasional problems arise with tooth brittleness, discoloration, and recurrent periapical inflammatory disease. Endodontic procedures also tend to be time consuming and expensive. Simplified one-step endodontic procedures to facilitate endodontic procedures have been described,3 but the success of these methods has not been adequately defined and has been challenged. Pulp-capping techniques have been used, but their success has been significant only in children, where they constitute an acceptable procedure.4~s Pulp capping is a simple technique, and the material currently favored is calcium hydroxide, which has been shown to favor the development of a calcified layer over the exposed pulp. However, calcium hydroxide has been shown to be more highly irritating to the dental pulp than zinc oxide and eugeno1,6 and the calcific bridge may represent a pathologic calcification. A new approach to the treatment of carious exposures, deep carious involvement of teeth, and caries-stimulated pulpitis is presented; it is based on initial animal studies and use in human beings. This procedure involves the use of potassium nitrate (KNO,) as a pulp-capping material or as a liner for deep carious lesions that closely approach the pulp. Potassium nitrate, following its introduction by Hodosh7 as a superior desensitizing agent for hypersensitivity of exposed root surfaces, has been evaluated clinically in several studies and its effectiveness has been well documented.8~Q It was thought that potassium nitrate might also have some success in preventing the discomfort and restoring the health of pulpal tissues in deep carious lesions or actual pulpal exposures. Potassium nitrate was mixed with carboxylate cement and used to cover exposed vital pulp tissue, and the initial results were so promising that its use was continued and documented. Toxicity studies were carried out in animals prior to human use. Animals used were albino mice, Sprague-Dawley rats, and beagle dogs. Safety of the agent was documented.‘O Mechanical exposures were created in four molar teeth of a dog, and the pulpal openings were sealed with potassium nitrate and carboxylate cement. ‘* The pulps were free of histologic evidence of inflammatory disease in three of the four teeth after 2 weeks. The fourth tooth presented a chronic pulpitis. Daily brushing with a 5 percent potassium nitrate paste for 4 weeks was found to be safe for dental pulp, while still exerting a significant desensitizing effect in hypersensitive teeth. Sixty teeth scheduled for extraction were selected for study, and the pulps were observed microscopically for evidence of disease. Pulpal tissues of all teeth were found to be essentially norma1.12