ENDO, 02/2008

Prior to root canal therapy, the pulp chamber needs to be accessed to allow mechanical preparation and chemical disinfection of the root canal system. An optimised access facilitates safe and effective endodontic therapy; however, errors during access, in particular over-preparation and under-preparation, may cause problems in subsequent procedures. Detailed understanding of normal anatomy and its variations is imperative and needs to be supplemented with a thorough analysis of the particular case being treated. Odontogenesis and the deposition of tertiary dentine play an important role in determining the location and extent of the penetration into the pulp chamber, as well as the location and trajectory of the coronal root canal portion. High- and slow-speed handpieces with a set of burs along with dedicated hand instruments have been used for endodontic access for decades. More recently, the increasingly widespread addition of the operating microscope and ultrasonically powered instruments has improved the chances of locating orifices, removing mineralisation and optimising access cavities. Locating all present orifices is crucial to the preparation of all canals, and straight-line access, including removal of restrictive coronal dentine and shaping of the coronal third of the root canal, is important for the successful use of nickeltitanium rotary instruments. This review presents the knowledge base and clinical guidelines for safe and efficient access cavity preparation. Keywords: anatomy, endodontic access, instruments, procedural errors

Aim: The aim of this study was to collect data on the prevalence of apical periodontitis in relation to the coronal status of teeth in xerostomic head and neck radiation patients and to compare these figures with data from a general population. Materials and methods: Panoramic radiographs of 43 patients lacking dental treatment during and after radiotherapy, taken on average 22.2 months after radiotherapy, were examined for periapical and coronal condition. The findings were compared with a matched control group (data in parentheses). Results: A total of 709 teeth were scored, and 5.6% (9.0%) were endodontically treated. Apical periodontitis was found in 7.8% (9.5%) of teeth and in 12.5% (43.1%) of the endodontically treated teeth. Of all teeth, 86.2% (17.5%) were decayed, with radiographic evidence of caries extending into the pulpal space in the majority of cases. Conclusions: No difference was found in the prevalence of apical periodontitis between the two populations in spite of a high incidence and severe degree of caries that could have lead to a higher incidence of apical periodontitis than in the general population. Bacterial shifts in the oral cavity and root canal, resulting in a less pathogenic flora and/or a change in cellularity and vascularisation of irradiated bone is a possible explanation. Keywords: apical periodontitis, coronal leakage, head and neck irradiation, radiotherapy, xerostomia

In this review article, different dental materials for the temporary restoration of the endodontic access cavity are presented and examined for sealing ability, antibacterial properties and the influence of intracanal medications. On the basis of the studies presented, recommendations for clinical procedures are made. Keywords: access cavity, root canal treatment, sealing ability, temporary restorative

Good practice guidelines recommend the use of rubber dam for all nonsurgical endodontic procedures; there are also safety and medico-legal implications. However, many unfounded reasons have been cited for not using rubber dam. By explaining why it is essential when performing endodontic treatment, and describing the various techniques of placement, the hope is that it will encourage the routine use of rubber dam in everyday clinical practice. Keywords: asepsis, medico-legal, rubber dam

A 21-year-old female patient was referred to the Department of Operative Dentistry of the University of Rostock because of complaints in the right maxilla indicating pulpitis in a maxillary molar. Tooth 17 had an extra cusp with an additional root on the buccal aspect. The point of fusion of the additional root with the regular tooth created an environment conducive to caries. The pulp chamber of the supernumerary root was opened during caries excavation and the clinical examination suggested a separate, supernumerary root canal. A standard radiograph showed no extraordinary root canal configuration, so during the first appointment only the supernumerary root canal was treated. Owing to continuing discomfort, a more precise radiological diagnosis was made using computed tomography (CT). The CT scan clearly showed that the separate root canal under the extra cusp communicated with the regular root canal system. Therefore, the diagnosis 'double teeth with incomplete gemination' was made and followed by root canal treatment for all the root canals. Keywords: dental anatomy, fusion, gemination, hyperdontia, supernumerary teeth