ENDO, 04/2010

The odontoblasts of dental pulp tissue form primary and secondary dentine. If the pulp tissue is exposed, the odontoblast layer will be destroyed. The aim of direct pulp capping is to induce new hard tissue formation in order to keep the pulp tissue vital. If direct pulp capping is successful, tertiary dentine is formed. This hard tissue is denoted as 'reparative dentine' and defined as a dentine matrix, which is formed by a new generation of odontoblast-like cells after an appropriate stimulus. Thus, reparative dentine is not formed by the original post-mitotic odontoblasts. Until recently it has been unclear which pulp cells differentiate into these odontoblast-like cells. Besides multipotent adult stem cells, fibroblasts and un-differentiated mesenchymal cells are mentioned in the literature as progenitor cells for odontoblast-like cells, because their cell-division rate increases significantly after direct pulp capping. The increase in the cell division rate of fibroblasts can be explained by the formation of granulation tissue, rather than the differentiation into secondary odontoblasts, as often described. A review of the relevant literature demonstrated that Höhl cells play a role in the formation of new odontoblast-like cells, and may well be activated after pulp tissue damage to form reparative dentine. Thus, for direct pulp capping, only wound dressings such as calcium hydroxide or mineral trioxide aggregate (MTA) should be used, as they are able to induce the proliferation of 'progenitor cells' (e.g. Höhl cells) in order to stimulate the formation of reparative dentine. Keywords: dentine formation, Höhl cell, odontoblast, pulp cells, reparative dentine

The aim of the present in vitro study was to determine the influence of different gutta-percha solvents used in endodontic retreatment cases on the accuracy of the Root ZX II electronic apex locator in locating the apical foramen. Thirty human, single-rooted permanent teeth were divided into three groups according to the solvent used: group OPO (orange peel oil, n = 10), group XYL (xylol, n = 10) and group CHL (chloroform, n = 10). Tooth length was established visually under 5× magnification with the aid of an optic microscope and then compared with the corresponding electronic measurement with a safety margin of ±0.5 mm. The results were analysed by the Biostat 4 program. The electronic and visual measurements coincided in 90% of the cases for xylol, in 100% of the cases for chloroform and in 100% of the cases for orange peel oil. No significant difference was observed among the three gutta-percha solvents in accurately locating the apical foramen (P = 0.607). Based on the results, it was possible to conclude that the accuracy of Root ZX II was not adversely affected by the presence of the gutta-percha solvents used in endodontic retreatment cases. Keywords: electronic apex locator, tooth length determination, working length

Treatment of combined endodontic-periodontal lesions is difficult to achieve successfully. It is still more complicated if accompanied by some developmental anomaly. The present article presents a case of a maxillary lateral incisor with a palatogingival groove and open apex, along with a draining sinus tract and severe bone loss. Teeth with such anomalies were often extracted in previous times. But now, due to development of newer materials such as MTA and bone graft materials along with better treatment techniques, these teeth can be preserved. In the present case, the groove was eliminated by saucerisation and using MTA to close an open apex for the creation of an apical plug. The patient was asymptomatic and radiographic healing was observed after a period of 1 year. Keywords: endodontic-periodontal lesions, MTA, open apex, palatogingival groove

Aim: To investigate the root canal morphology of mandibular incisors in a northeast Indian population, using a root canal staining and tooth-clearing technique. Methodology: A total of 480 extracted mandibular incisors, collected from dental clinics within northeast India, were selected for the present study. Following pulp tissue removal, the teeth were decalcified with 5% nitric acid, dehydrated with increasing concentrations of alcohol and rendered clear by immersion in methyl salicylate. After staining the root canal systems with Indian ink, the cleared teeth were examined under 5× magnification, and the following features were evaluated: (i) number and type of root canals; (ii) location of apical foramina; (iii) presence and location of lateral canals, anastomoses and ramifications; and (iv) bifurcation of root canals. Results: The majority of mandibular incisors had a single root canal (63.75% of teeth possessed a Type I canal system). Although 36.25% of the roots possessed two canals, only 6.25% had two separate apical foramina. Conclusions: The prevalence of two root canals in this group of mandibular incisors was 36.25%, within the range of results from previous studies performed on populations of different racial origins. Keywords: anastomoses, lateral canals, mandibular incisors, morphology, root canal types

Gemination is a rare occurrence and its definitive diagnosis is of prime importance for successful management. This case report discusses the endodontic and periodontal management of a geminated right maxillary lateral incisor of a 16-year-old male patient. Keywords: complex root canal morphology, endodontic-periodontal lesion, gemination, incompletely cleaved root

Aim: To present a case report describing the diagnosis and treatment of an extraoral cutaneous sinus tract of odontogenic origin in relation to a mandibular left central incisor. Summary: The extraoral cutaneous sinus tract of dental origin is an uncommon, but well-documented condition. However, several non-odontogenic disorders may also cause an extraoral sinus tract. The diagnosis is not always easy unless the treating clinician considers the odontogenic origin. The present case report discusses diagnosis and treatment of an extraoral cutaneous sinus tract of odontogenic origin in relation to a mandibular left central incisor (diagnosed as asymptomatic suppurative periradicular periodontitis with an extraoral cutaneous sinus tract opening in the mandibular mental region). Non-surgical endodontic therapy was performed under oral antibiotic therapy. During instrumentation, a nickel-titanium rotary file became separated in the middle and apical third of the canal, thus making the case more challenging. The instrument was retrieved with the use of an ultrasonic tip. The patient responded well, and the cutaneous lesions healed uneventfully. Keywords: extraoral cutaneous tract, non-surgical endodontic treatment, separated endodontic files, ultrasonic tips

Aim: Knowledge of root canal anatomy is crucial for successful root canal therapy. An in vitro study was performed to evaluate the number of roots, root canals and their types, level of division and fusion, curvature, location of apical foramina, transverse anastomosis and frequency of apical deltas in maxillary second premolars and to compare these findings with their radiographs. Materials and methods: A total of 90 extracted maxillary second premolars were collected and radiographed in a mesiodistal as well as buccolingual direction. The teeth were then decalcified, cleared and injected with haematoxylin dye. All of the specimens were examined under a stereomicroscope. The examination of the root canal system was based on Vertucci's classification. Results: In total, 94.4% of the teeth had one root and 5.6% had two roots. In cleared specimens, the percentage of Type I canals was 24.4%, Type II 34.4%, Type IV 27.8%, Type V 6.6% and Type VI 6.7%. The radiographic interpretation of the buccolingual view was found to be significantly different from the actual morphology (phi = 0.6, P < 0.001) and the mesiodistal view provided most of the information. Conclusions: A careful study of the radiographs is important. Cone angulation techniques should be used for determining root canal complexities, so as to treat a maximal number of canals. This paper was presented at the 23rd FODI (Federation of Operative Dentistry of India) and 16th IES (Indian Endodontic Society) National Conference held in Kochin, India on 15 November, 2009. Keywords: canal morphology, decalcification, maxillary, radiographs, second premolar

Taurodontism is an important abnormality in tooth morphology. Therefore, this anatomical disparity requires an understanding of the tooth morphology, which is essential for cavity preparation, root canal therapy and extraction. Metric analysis was carried out through categorisation, by means of intraoral periapical radiographs that were exposed using an extension cone paralleling (XCP) instrument (paralleling technique), and superimposed with a calibrated grid. This revealed hypertaurodont premolars in two patients and six hypertaurodont and two hypotaurodont molars in another patient. Keywords: bull-like teeth, endodontic therapy, XCP

A root anomaly in primary canines is a rare entity. Primary maxillary canines have a single conical root, but a few bi-rooted canines have been reported previously in the literature. This report presents a unique anomaly of a primary maxillary right canine (PMRC) with three roots and its endodontic treatment. Such an anatomic variation has not been reported previously. On radiographic examination the contralateral canine and the mandibular canines were single rooted. The purpose of the present case report is to increase awareness about this morphological aberration and its clinical significance. Keywords: endodontic treatment, primary maxillary right canine, root anomaly, three-rooted

Accidental swallowing of instruments during endodontic procedures is often unheard of, but when it does occur it causes much anxiety to the endodontist. When swallowing of an endodontic instrument occurs, the endodontist should have basic knowledge about the procedures, complications and methods of retrieving the swallowed instrument, as well as an ability to reassure the patient. The present study discusses a case report of successful retrieval of a swallowed endodontic instrument and also highlights the various complications that may arise due to accidental swallowing of instruments and their treatment modalities. Keywords: accidental swallowing, endodontic file, foreign body, iatrogenic error