Access to original canal trajectory after deviation and perforation with guided endodontic assistance.

Procedural accidents are eventualities that may occur during endodontic treatment because of lack of attention to detail or even unforeseeable situations. Knowledge of the root canal anatomy and its variations is a prerequisite for successful endodontic treatment. This case report describes an endodontic treatment where there was an intercurrence, generating deviation and perforation, which was solved with the aid of guided endodontics. A 37 years old, ASA1, was referred to the clinic for localisation and treatment of a calcified canal of the second right upper premolar. The tomographic images revealed the presence of only one canal and deviation with apical perforation. With the help of CBCT and CAD/CAM, it was possible to perform the guided access technique even after deviation and root perforation. Once again, this technique proved to be safe and predictable, allowing for a favourable prognosis in the long term.

Endodontia guiada como alternativa para o tratamento de canais severamente calcificados / Guided endodontics as an alternative for the treatment of severely calcified canals

ntrodução: a calcificação pulpar é um dos fatores que tornam o tratamento endodôntico desafiador e capaz de comprometer o acesso dos instrumentos e soluções irrigadoras por toda extensão do canal radicular, impossibilitando sua adequada desinfecção. A Endodontia Guiada traz mais previsibilidade e segurança ao tratamento endodôntico nessa situação complexa. Métodos: uma vez constatada calcificação severa com necessidade de intervenção endodôntica, o paciente é encaminhado ao centro radiológico para o planejamento da Endodontia Guiada. Um modelo 3D da arcada a ser tratada é obtido por meio de um scanner de bancada e, posteriormente, transferido para um software de planejamento virtual de implante. A TCFC é adicionada a esse software e ambas são sobrepostas, com base em estruturas visíveis radiograficamente. O software Simplant é programado para projetar uma broca física, utilizada para o acesso endodôntico guiado, sobreposta virtualmente à calcificação do canal radicular. De posse da guia impressa, essa é posicionada na arcada do paciente e o procedimento clínico, executado. Conclusão: a técnica de Endodontia Guiada é rápida, previsível e clinicamente viável. Além disso, pode ser executada por profissionais menos experientes, não necessitando da utilização de microscópio operatório (AU).

Introduction: Pulp calcification is one of the factors that make endodontic treatment challenging and capable of compromising access of instruments and irrigant solutions to the entire extension of the root canal, making it impossible to disinfect it adequately. Guided endodontics makes the endodontic treatment more predictable and safer in this complex situation. Materials and Methods: Once severe calcification requiring endodontic intervention has been found, the patient is referred to the radiology center for the planning of guided endodontics. A 3D model of the arch to be treated is obtained by means of a bench scanner, afterwards transferred to a virtual implant planning software program. The CBCT is added to this software and both are superimposed on the basis of radiographically visible structures. The Simplant software is programmed to project a physical bur used for guided endodontic access, virtually superimposed on the root canal calcification. Once the printed guide has been obtained, it is positioned in the patient's arch and the clinical procedure is performed. Conclusion: The guided endodontic technique is easy, predictable and clinically feasible to perform. Moreover, it may be performed by less experienced professionals, and does not require the use of an operating microscope (AU).

A New Approach for Minimally Invasive Access to Severely Calcified Anterior Teeth Using the Guided Endodontics Technique.

This article describes an endodontic treatment technique performed through a new minimally invasive approach that leads to no tooth damage at the incisal edge and uses cone-beam computed tomographic (CBCT) imaging and 3-dimensional guides. A 26-year-old patient presented with pain in the anterior region of the maxilla and reported having suffered dental trauma 13 years prior. Radiographic examination exhibited no visible root canal on tooth # 9 with a slight thickening in the apical periodontal ligament space. Pulp sensitivity tests produced no response, whereas the percussion test responded positively. CBCT imaging revealed a visible canal space limited to the apical 2-mm section of the root. Guided endodontic access was planned after intraoral scanning of the tooth surface to be used with the CBCT scan. A virtual model was created with the aid of virtual implant software for the surgical access planning in such a way as not to damage the incisal edge of the tooth. The resulting guides were printed. With guides in position over the rubber dam, a mechanical-chemical preparation was performed in the root as soon as the canal was located. Intracanal medication was left for 14 days, after which the root canal was filled gutta-percha and the access cavity sealed. Follow-up was performed 1 year after completion of the treatment. The patient was asymptomatic with periapical tissue within normal limits. The guided endodontic therapy optimized the treatment, having provided a conservative access with no tooth damage at the incisal edge in a safe and predictable way despite the presence of a severely calcified root canal.

Guided Endodontic Access in Maxillary Molars Using Cone-beam Computed Tomography and Computer-aided Design/Computer-aided Manufacturing System: A Case Report.

The aim of this study was to describe a guided endodontic technique that facilitates access to root canals of molars presenting with pulp calcifications. A 61-year-old woman presented to our service with pain in the upper left molar region. The second and third left molars showed signs of apical periodontitis confirmed by the cone-beam computed tomographic (CBCT) scans brought to us by the patient at the initial appointment. Conventional endodontic treatment was discontinued given the difficulty in locating the root canals. Intraoral scanning and the CBCT scans were used to plan the access to the calcified canals by means of implant planning software. Guides were fabricated through rapid prototyping and allowed for the correct orientation of a cylindrical drill used to provide access through the calcifications. Second to that, the root canals were prepared with reciprocating endodontic instruments and rested for 2 weeks with intracanal medication. Subsequently, canals were packed with gutta-percha cones using the hydraulic compression technique. Permanent restorations of the access cavities were performed. By comparing the tomographic images, the authors observed a drastic reduction of the periapical lesions as well as the absence of pain symptoms after 3 months. This condition was maintained at the 1-year follow-up. The guided endodontic technique in maxillary molars was shown to be a fast, safe, and predictable therapy and can be regarded as an excellent option for the location of calcified root canals, avoiding failures in complex cases.

Long-term ammonia removal in a coconut fiber-packed biofilter: analysis of N fractionation and reactor performance under steady-state and transient conditions.

A comprehensive study of long-term ammonia removal in a biofilter packed with coconut fiber is presented under both steady-state and transient conditions. Low and high ammonia loads were applied to the reactor by varying the inlet ammonia concentration from 90 to 260 ppm(v) and gas contact times ranging from 20 to 36 s. Gas samples and leachate measurements were periodically analyzed and used for characterizing biofilter performance in terms of removal efficiency (RE) and elimination capacity (EC). Also, N fractions in the leachate were quantified to both identify the experimental rates of nitritation and nitratation and to determine the N leachate distribution. Results showed stratification in the biofilter activity and, thus, most of the NH(3) removal was performed in the lower part of the reactor. An average EC of 0.5 kg N-NH(3)m(-3)d(-1) was obtained for the whole reactor with a maximum local average EC of 1.7 kg N-NH(3)m(-3)d(-1). Leachate analyses showed that a ratio of 1:1 of ammonium and nitrate ions in the leachate was obtained throughout steady-state operation at low ammonia loads with similar values for nitritation and nitratation rates. Low nitratation rates during high ammonia load periods occurred because large amounts of ammonium and nitrite accumulated in the packed bed, thus causing inhibition episodes on nitrite-oxidizing bacteria due to free ammonia accumulation. Mass balances showed that 50% of the ammonia fed to the reactor was oxidized to either nitrite or nitrate and the rest was recovered as ammonium indicating that sorption processes play a fundamental role in the treatment of ammonia by biofiltration.

Demographic profile of odontogenic and selected nonodontogenic cysts in a Brazilian population.

OBJECTIVE: To determine the demographic profile of all histologically diagnosed odontogenic cysts (OC) and nonodontogenic cysts (nOC) over a 51-year period in the Brazilian population. STUDY DESIGN: Case records of patients with OC and nOC from the files of the Oral Pathology Service, School of Dentistry, Federal University of Minas Gerais, Belo Horizonte, Brazil, during the period of 1953-2003 were evaluated. RESULTS: Among 19,064 oral biopsies, 2,905 (15.2%) presented criteria of OC and nOC. Of these, 2,812 specimens (14.7%) were diagnosed as OC and 93 (0.5%) represented nOC. The 3 most frequent OC diagnosed were radicular cyst (61.0%), dentigerous cyst (25.3%), and odontogenic keratocyst (7.2%). The most frequent nOC was the nasopalatine duct cyst (2.2%). CONCLUSION: Our results demonstrate that there is a wide range of OC and nOC, with some cysts having a predilection for age, gender, and localization. We also showed demographic aspects and clinical characteristics of these cysts. These could be used as baseline data to obtain more epidemiologic information about the OC and the nOC especially in the Brazilian population.