REVIEW ARTICLE: Calcium hydroxide has been used in endodontology for many years. The aim of this paper is to review the various formulations of calcium hydroxide that have been described, with specific reference to the vehicle used to carry the compound. The requirements for a vehicle are described, and ex vivo and in vivo studies reviewed. Vehicles can be classified into aqueous, viscous and oily, the clinical properties of calcium hydroxide changing depending on the vehicle. The review also describes the use of various active components that have been added to calcium hydroxide, including antimicrobial and anti-inflammatory agents. This review will help clinicians to make informed judgements about which formulations of calcium hydroxide should be used for specific endodontic procedures.

The objective of this article is to describe various radiographic projections which can be used during endodontic therapy. Changes to the angulation of the X-ray beam in relation to the teeth and film can help diagnosis and treatment by producing images which provide additional information not always visible on radiographs taken with standard angulations. For example, changes in angulation can be useful to determine the number and curvature of roots and canals, to identify superimposed roots and to distinguish between anatomical landmarks and apical pathology. Although use of such techniques increases the diagnostic yield of films, it must be appreciated that such views lead to images that are less distinct because of inherent image distortion. Nevertheless, use of the various techniques during endodontics can provide substantial benefit for clinicians in their daily practice.

Studies on canal configuration have demonstrated a substantial variation in the number of roots and root canals in different teeth. Maxillary and mandibular molars may have three and two roots, respectively, and generally present with three of four root canals. This case describes the presence of one single root and one root canal in all second molars of the same patient.

A clinical study using upper central incisors was carried out to evaluate the incidence of postoperative pain after root canal preparation by the double-flared technique. Sixty teeth with necrotic pulps from 48 patients whose ages ranged from 12 to 65 years were prepared and filled in either one or two appointments. No difference was observed in the incidence of postoperative pain between the two groups.

Success in root canal treatment is achieved after thorough cleaning and shaping followed by the complete obturation of the root canal system. Such treatment may be performed in root canal systems that do not comply with the normal anatomical features described in standard textbooks. The present case describes root canal treatment in a maxillary first molar with two roots and a type IV canal configuration in the buccal root. KEY LEARNING POINTS Careful examination of radiographs and the internal anatomy of teeth is essential. Root canal treatment is likely to fail if the entire system is not debrided and filled. Anatomic variations can occur in any tooth.