ENDO, 02/2009

The main objective of endodontic treatment is to eliminate microorganisms and prevent re-infection within the root canal. However, root canal infections are polymicrobial and difficult to eliminate due to anatomical complexity. Besides the instrumentation, irrigation is an important step for disinfection. However, because the traditional irrigants can be ineffective in some cases, there is increasing interest in alternative irrigation solutions such as chlorhexidine (CHX). CHX is a widely used medical antiseptic and disinfectant. It is a broad-spectrum antimicrobial agent and has a comparable antimicrobial efficiency as both a root canal irrigant and intracanal medicament. It also has unique properties such as residual antimicrobial effects. This paper presents the chemical, pharmacological and antimicrobial properties of CHX. In addition, an overview of the clinical applications and the pros and cons of the use of chlorhexidine in endodontics is presented. Keywords: antimicrobial, chlorhexidine, disinfection, irrigation, substantivity

Radiographic examination aids in the many steps of endodontic treatment, from diagnosis and treatment planning to assessment of outcome. The amount of information gained from conventional film and digitally captured intraoral radiographs is invaluable, but also limited. To some extent, particular clinical and biological features may not be reflected in radiographic images, because the three-dimensional anatomy is compressed into a two-dimensional image. This results in the superimposition of anatomical structures onto the features of diagnostic interest, sometimes to the extent that the latter become concealed. Therefore, the presence of a lesion may not be directly evident, and its real extent and the spatial relationships to important anatomical landmarks are not always easily visualised. There may also be geometric distortion of the anatomical structures being imaged. Also, exposure parameters, image processing, viewing conditions, and the training and experience of the human observer all affect the quality of radiographic examination. This paper reviews some aspects of the usefulness and limitations of the radiographic examination in periapical diagnosis. Keywords: apical periodontitis, radiographic techniques

This article considers the evidence underpinning the UK Health Department's guidance that root canal instruments must be treated as single use as a precaution to reduce any risk of variant Creutzfeldt- Jakob disease (vCJD) transmission. Although there have been fewer than 170 clinical cases of vCJD in the UK to date, there is concern that an unknown number of the population may carry vCJD infection without showing symptoms. This creates the potential for secondary (person-to-person) transmission, as has happened via blood transfusion. There is currently no evidence of vCJD having been spread by dentistry, but animal models suggest that this may be possible. In particular, evidence presented by the Health Protection Agency (HPA) from a bioassay study has indicated that murine oral tissues, for example dental pulp, can harbour prion infectivity. It is possible that dental/oral tissues of humans infected with vCJD could also carry infection. If so, residual protein adhering to dental instruments may transmit vCJD infection to other patients. Decontamination would reduce this risk, but a number of clinical studies have shown that the decontamination methods used in dentistry would not eliminate the risk entirely. Furthermore the large number of dental procedures carried out each year means that even small transmission risks per procedure could create an appreciable risk to public health. Given that there are many uncertainties, including the infectivity of relevant tissues in those incubating the disease, the typical effectiveness of instrument decontamination, and the current prevalence of subclinical infection, a precautionary approach is warranted. Specifically, this article supports the decision that root canal instruments must be treated as single use, as well as promoting further initiatives to improve the effectiveness of decontamination for the generality of dental instruments. Keywords: Creutzfeldt-Jakob disease, cross-infection, endodontic files, prions, residual protein

Aim: To present a case report of root canal therapy on a mandibular first molar with a supernumerary distolingual root (radix entomolaris). Summary: An additional distolingual root, the radix entomolaris is a major anatomical variant of the tworooted mandibular first molar. Awareness and understanding of this unusual root morphology contributes to the success of root canal therapy. This report discusses endodontic retreatment of a mandibular molar with a radix entomolaris, which is a rare macrostructure predominantly found in Caucasian populations.

The inter-relationship between periodontal and endodontic disease has aroused much speculation, confusion and controversy. Pulpal and periodontal problems are responsible for more than 50% of tooth loss today. The prognosis of a true combined lesion is often poor or even hopeless, especially when there is extensive periodontal destruction. The present report describes the use of platelet-rich fibrin (PRF) gel and membrane in combination with a bone graft for treating a tooth with a combined periodonticendodontic lesion. The tooth was endodontically and periodontally treated. Clinical and radiographic follow-up was performed after 6 and 12 months. After 1 year, the absence of a interradicular lesion, pain and swelling along with tooth stability and adequate radiographic bone fill indicated a successful outcome. The success of treating a combined periodontic-endodontic lesion depends on patient cooperation, restorability and economics, which help in acting on treatment decisions. Keywords: furcation, Periobone-G, periodontal abscess, periodontic-endodontic lesion, plateletrich fibrin (PRF), regeneration

Pulpal necrosis after dento-alveolar trauma of immature permanent teeth can cause a substantial problem for both patient and practitioner. Traditional therapy includes apexification with calcium hydroxide or the one-step apical plug procedure with mineral trioxide aggregate. The case presented here illustrates how an immature central incisor in a young individual, in which treatment was planned for a one-step apical plug technique after trauma and subsequent pulp necrosis, displayed root maturation due to the longterm course of the treatment. Keywords: apexification, apexogenesis, crown fracture, immature root, MTA, pulpotomy

A case of dens invaginatus in a maxillary lateral incisor with a periapical lesion (that was discovered by chance after a panoramic radiographic examination despite the abnormal anatomy) responded successfully to non-surgical treatment involving chemomechanical root canal preparation associated with longterm treatment with calcium hydroxide. Keywords: apexification, apexogenesis, crown fracture, dens invaginatus, immature root, MTA, pulpotomy, intracanal medication, peri-radicular lesion, root canal treatment