ENDO, 03/2011

The ultimate goal of endodontic microsurgery is the predictable regeneration of periapical tissues and osseous defects. Although every step of endodontic microsurgery has dramatically improved over the past years, little attention has been paid to the bone defect topography underlying the soft tissue. This paper presents a classification of bony defects as faced during endodontic microsurgery, discusses current techniques and materials for the management of such lesions and describes the clinical procedures for the management of bony defects. Keywords: endodontic microsurgery, guided bone regeneration, guided tissue regeneration, osteogenesis

Chelators were first introduced into endodontics by Nygaard-Ostby in 1957, who recommended the use of a 15% EDTA solution. A few years later, a detergent was added in order to increase the cleaning and bactericidal potential of the EDTA solution. Since then, the search for ideal chelating agents has continued and led to many new chelator preparations in endodontics. This paper reviews the relevant literature on chelating agents, presents an overview of their chemical and pharmacological properties and makes recommendations for their clinical use. Keywords: chelators, dentine hardness, EDTA (ethylenediamine tetra-acetic acid), smear layer

Sodium hypochlorite (NaOCl) in various concentrations is the most widely used root canal irrigant, but it can be an irritant to vital tissue. There are several reports about complications of root canal irrigation with NaOCl. Most of them are the result of accidental extrusion beyond the apex. The inadvertent injection of NaOCl instead of local anaesthetic solution is an extremely rare misuse and results in severe problems. The consequences of the inadvertent injection of sodium hypochlorite, precautions to avoid such accidents and also treatment options are discussed. Sodium hypochlorite is highly irritating when introduced into oral tissues. To avoid inadvertent injection of sodium hypochlorite during root canal treatment, NaOCl solutions should be prepared in special syringes, which are clearly distinguishable from syringes used for other solutions or anaesthetics. Lower concentration NaOCl solutions should be preferred to higher or full-strength solutions. Keywords: ecchymosis, haematoma, oedema, paraesthesia, tissue necrosis

This study used multislice computed tomography to evaluate the amount of the remaining cervical dentine thickness in human mandibular first molars after coronal flaring with six different orifice shapers. Sixty mesial roots were divided into six equal groups. Coronal flaring was performed by using X-Gates, Endoflare, Pre-RaCe, Protaper SX, SafeSider Pleezer or NRT instruments. Changes in the cervical dentine thickness of the mesiobuccal and the mesiolingual canals were measured before and after coronal flaring by using multislice computed tomography and image analysis software. Statistical analysis of the mean change percent in the cervical dentine thickness showed that for the mesiobuccal canals, there were no statistically significant differences between the experimental groups and also between the mesial and distal cervical wall thicknesses within the same group (P > 0.05). The same result was obtained after coronal flaring of the mesiolingual canals except in the group prepared with the SafeSider Pleezer instruments, where the change in percent of the distal cervical wall thickness was significantly more than the mesial one (P = 0.05). Keywords: computed tomography, coronal flaring, remaining dentine thickness

Aim: The objective of the present study was to compare the radiopacity of endodontic sealers based on three different chemical compositions: epoxy resin and calcium hydroxide (Acroseal and Sealer 26), zinc oxide eugenol (Endofill, Endométhasone N, N-Rickert), and methacrylate resin (RealSeal). Materials and methods: Three specimens measuring 10 mm in diameter and 2 mm in thickness were prepared from each test material and radiographed next to a 1- to 8-mm-thick aluminium stepwedge using occlusal films. The radiographs were digitised, and optical density was used to determine the radiopacity of the materials according to a greyscale with levels ranging from 0 to 255. The data was submitted to the variance test (ANOVA, P 0.05) as well as to the Ryan-Einot-Gabriel-Welch and Quiot test (REGWQ) for multiple comparisons of the means. Results: The greyscale level means for the materials, in increasing order, were: Acroseal - 125.3; Sealer 26 - 144.3; Endométhasone N - 155; Endofill - 175.3; RealSeal - 183; N-Rickert - 188.3. None of the materials presented a radiopacity mean level significantly lower than that obtained with 4 mm of aluminium (111.3), which was used as a reference to compare the sealers following ANSI/ ADA specification 57 (2 mm thicker than the test specimen). Conclusions: All of the endodontic sealers evaluated presented a radiopacity level above the minimum required. Keywords: dental materials, dental radiography, endodontics, root canal obturation, sealer

Introduction: A case of unusual root morphology is presented to demonstrate anatomic variations in mandibular second molars. The most common configuration of mandibular second molars is to have two roots with three root canals; however mandibular molars may have many different combinations. Methods: Root canal endodontic treatment was performed in a mandibular second molar with three separate roots, two located distally and one mesially. Radiographically, all four root canals terminated with individual foramen. Results: Four orifices or four independent canals were found in three separate roots, indicating a rare anatomic configuration, and confirmed with the help of spiral computed tomography (SCT). Conclusion: Looking for additional roots, root canals and unusual morphology is an important part of successful root canal treatment, as the knowledge of their existence occasionally enables clinicians to treat a case that otherwise might have ended in endodontic failure. The use of SCT imaging in this case greatly contributed to a confirmed diagnosis and successful root canal treatment thereafter. Keywords: radix entomolaris, spiral computed tomography scan, three-rooted mandibular second molar