Summary. Calcium hydroxide is a material which has been used for a variety of purposes since its introduction into dentistry in the early part of the twentieth century. In its pure form, the substance has a high pH, and its dental use relates chiefly to its ability to stimulate mineralization, and also to its antibacterial properties. A range of products has been formulated with different therapeutic actions, the effects of which are partially dependent upon the tissue to which they are applied. The material is reviewed under the following general headings: biochemical actions; dental formulation; uses.

A review of calcium hydroxide

‘Prognosis’ is the forecast of the course of a disease. In the context of apical periodontitis, therefore, this term applies to both the time course and chances of healing. Over the past 80 years, an extensive volume of studies has been amassed that focuses on the prognosis of apical periodontitis after endodontic therapy. Cumulatively, the authors of these studies have recorded, grouped, and analyzed data from thousands of treated cases. Two major reviews had summarized the state-of-the-art knowledge at different timesa Strindberg (1) reviewed studies reported in the first half of the 20th century, and Friedman (2) reviewed studies reported from 1956 up to 1997. From those comprehensive reviews it has become obvious that the data pertaining to the prognosis of apical periodontitis after endodontic therapy is inconsistent and largely variable (2). Apparently, the wealth of available information is somewhat confused by the lack of standardization among the studies, with respect to material composition, treatment procedures, and methodology (2). Furthermore, certain clinical procedures performed in specific studies may no longer be relevant to the current practice of endodontics. Clearly, therefore, undiscerning review of all the existing studies can be ineffective and even misleading. For a review to yield reliable and valid information, it must focus on studies selected according to well-defined criteria. The purpose of this article is to review and discuss selected articles on the prognosis of initial endodontic therapy of apical periodontitis.

Prognosis of initial endodontic therapy

Root perforations are common complications of endodontic treatment or post preparation and often lead to tooth extraction. Successful treatment depends mainly on immediate sealing of the perforation and prevention of infection. Several factors affect the achievement of these goals, most important of which are: time of occurrence, size, and location of the perforation. A classification of root perforations, based on the above factors, is presented to assist the clinician in the choice of the treatment protocol which will give the best possible results when a perforation is diagnosed.

Root perforations: classification and treatment choices based on prognostic factors.

Dear Colleagues

I feel honoured and excited to participate in Endodontic Topics, the new review journal focusing on all aspects of the science and art of endodontics, and I hope you will join me in celebrating this first issue, wherever you are! In contrast to future issues, which will focus on one area each, this issue covers different areas, all reviewed by my fellow Associate Editors. I selected the following review for this issue because it touches on several topics that have been assigned to me to cover in the future. In this review, you will find reference to endodontic treatment outcome criteria, concepts of endodontic health and disease, decision-making, treatment outcome of apical surgery and orthograde re-treatment, post-operative pain associated with the aforementioned procedures, removal of crowns and posts, as well as broken instruments, perforation repair, retrograde re-treatment and more. All of these topics are dealt with in this article in the context of case selection in the management of post-treatment disease. In the future, however, you will see the focus shifting to examining each of these topics on their own, with many of them being reviewed in greater detail by those researchers and clinicians quoted in this review. So, to my mind, this review is not just a review but a sign of things to come.

I look forward to working with many knowledgeable colleagues in the future to develop good quality, comprehensive and critical reviews for your benefit. I hope you find these reviews exciting and useful.

Considerations and concepts of case selection in the management of post-treatment endodontic disease (treatment failure)

Exposed dentinal tubules in areas of denuded cementum may serve as communication pathways between the pulp and periodontal ligament (Fig. 1). Exposure of dentinal tubules may occur due to developmental defects, disease, or periodontal procedures. In the root, dentinal tubules extend from the pulp to the dentinocemental junction (73). They run a relatively straight course and range in size from 1 to 3 mm in diameter (126). The diameter of the tubules decreases with age or as a response to a continuous low grade stimuli by the apposition of highly mineralized peritubular dentin. The number of dentinal tubules varies from approximately 8,000 at the dentinocemental junction to 57,000 per square millimeter at the pulpal end (126). In the cervical area of the root there are about 15,000 dentinal tubules per square millimeter (73). These tubules may be denuded of their cementum coverage as a result of periodontal disease, surgical procedures or developmentally when the cementum and enamel do not meet at the cemento-enamel junction (CEJ) thus leaving areas of exposed dentin. Patients experiencing cervical dentin hypersensitivity are an example of such a phenomena. Scanning electron microscopic studies have demonstrated that dentin exposure at the CEJ occurrs in 18% of teeth in general and in 25% of anterior teeth in particular (132). Furthermore, the same tooth may have different CEJ characteristics with dentin exposure on one side while the other sides are covered with cementum (162). This area becomes important in assessing the progression of endodontic pathogens (Fig. 2), as well as the effect of root scaling and planing on cementum integrity, and bleaching-induced root resorption following the use of 30% hydrogen peroxide (50, 78, 153, 154). Other areas of dentinal communication may be through developmental grooves, both palatogingival and apical (173).

Diagnosis, prognosis and decision-making in the treatment of combined periodontal-endodontic lesions.

The treatment outcome of 55 root perforations in man were related to pretreatment conditions and various treatment procedures used, with a mean recall period of 3 years 5 months. In this study maxillary teeth were perforated three times more often (74.5 per cent) than mandibular teeth (25.5 per cent); 47 per cent of the perforations were due to endodontic and 53 per cent due to prosthodontic treatment. The buccal and mesial root surfaces as well as the midroot areas were most often perforated. In 25 per cent, radiographic changes were directly related to the perforated areas. Twenty-eight perforations were repaired by orthograde fillings with gutta-percha and Kloro-percha N-phi; eight received a combined orthograde and surgical repair, and in only three cases a surgical approach was used. Four cases received no treatment but were recalled, and twelve perforations showed a size and location hopeless for repair; the teeth were therefore extracted. Five failures of the primary orthograde treatment group later underwent surgical treatment and were followed up for 3 years 3 months. The overall success rate in the primary treatment group of teeth was 56 per cent while 36 per cent became failures. Five failures were retreated, and four of these became successful. A combined orthograde and surgical repair of the perforations provided the most favourable outcome with 92 per cent successful. The study stresses the importance of preventing this type of treatment complication.

I. Kvinnsland

Papers

A clinical and roentgenological study of 55 cases of root perforation