The effect of a manual instrumentation technique on five types of premolar root canal geometry assessed by microcomputed tomography and three-dimensional reconstruction

<p>Abstract</p> <p>Background</p> <p>Together with diagnosis and treatment planning, a good knowledge of the root canal system and its frequent variations is a necessity for successful root canal therapy. The selection of instrumentation techniques for variants in internal anatomy of teeth has significant effects on the shaping ability and cleaning effectiveness. The aim of this study was to reveal the differences made by including variations in the internal anatomy of premolars into the study protocol for investigation of a single instrumentation technique (hand ProTaper instruments) assessed by microcomputed tomography and three-dimensional reconstruction.</p> <p>Methods</p> <p>Five single-root premolars, whose root canal systems were classified into one of five types, were scanned with micro-CT before and after preparation with a hand ProTaper instrument. Instrumentation characteristics were measured quantitatively in 3-D using a customized application framework based on MeVisLab. Numeric values were obtained for canal surface area, volume, volume changes, percentage of untouched surface, dentin wall thickness, and the thickness of dentin removed. Preparation errors were also evaluated using a color-coded reconstruction.</p> <p>Results</p> <p>Canal volumes and surface areas were increased after instrumentation. Prepared canals of all five types were straightened, with transportation toward the inner aspects of S-shaped or multiple curves. However, a ledge was formed at the apical third curve of the type II canal system and a wide range in the percentage of unchanged canal surfaces (27.4-83.0%) was recorded. The dentin walls were more than 0.3 mm thick except in a 1 mm zone from the apical surface and the hazardous area of the type II canal system after preparation with an F3 instrument.</p> <p>Conclusions</p> <p>The 3-D color-coded images showed different morphological changes in the five types of root canal systems shaped with the same hand instrumentation technique. Premolars are among the most complex teeth for root canal treatment and instrumentation techniques for the root canal systems of premolars should be selected individually depending on the 3-D canal configuration of each tooth. Further study is needed to demonstrate the differences made by including variations in the internal anatomy of teeth into the study protocol of clinical RCT for identifying the best preparation technique.</p

Methods used to evaluate shaping ability of rotary endodontic files : state of the art

Dissertação para obtenção do grau de Mestre no Instituto Universitário Egas MonizThe aim of this project is to review and analyze the literature that studied the shaping ability of endodontic rotary files to answer the question: What is the most accurate method used to assess the shaping ability of rotary endodontic files based on the canal transportation and centering ability parameters? Search was performed using PubMed, MEDLINE, Embase, ScienceDirect, Scopus, e B-on databases. Studies published in English from January 2010 to February 2021, that specified centering ability and shaping ability of the rotary files, were included. 65 studies were included in the review from a cumulative sample of 615 studies. 48 studies used extracted teeth, while 17 studies used simulated root canals in resin blocks. 38 studies used Micro-Computed Tomography and Cone-Beam Computed Tomography (MCT+CBCT) while 26 studies used Double Digital Images Radiographs / Photographs (DDIR+DDIP) and software analysis, and only one used both DDIR and MCT. Shaping ability of the root canal instrumentation becomes essential with the introduction of new instruments to the market. MCT method and its breakthrough types become superior in evaluating the quality of root canal instrumentation since they can provide 3-dimentional picture.O objetivo deste projeto é efetuar uma revisão da literatura científica acerca da capacidade de preparação das limas rotatórias, para responder à seguinte questão: Qual a melhor técnica, com base nos parâmetros de capacidade de transporte e centralização, para avaliar a capacidade de preparação de limas rotatórias? A pesquisa foi realizada nas bases de dados PubMed, MEDLINE, Embase, ScienceDirect, Scopus e B-on. Estudos publicados em inglês de janeiro de 2010 a fevereiro de 2021, que especificavam a capacidade de centralização e a capacidade de modelagem das limas rotativas, foram incluídos. 65 estudos foram incluídos na revisão de uma amostra cumulativa de 615 estudos. 48 estudos usaram dentes extraídos, enquanto 17 estudos usaram canais radiculares simulados em blocos de resina. 38 estudos usaram tomografia micro-computadorizada e tomografia computadorizada de feixe cónico (MCT+CBCT), enquanto 26 estudos usaram imagens digitais duplas (DDIR+DDIP) e análise de software, e apenas um usou radiografia e MCT. A capacidade de conformação da instrumentação do canal radicular torna-se essencial com a introdução de novos instrumentos no mercado. O método MCT e os seus tipos inovadores tornam-se superiores na avaliação da qualidade da instrumentação do canal radicular, uma vez que podem fornecer imagens tridimensionais

An in-vitro comparative micro-computed tomographic evaluation of three obturation systems

Magister Chirurgiae Dentium - MChD (Prosthodontics)Gaps or voids between walls of root canal and obturation material may lead to re-infection of the obturated root canal. Therefore, adaptation of the obturation material to dentine walls is essential for the success of root canal treatment

The State of the Art in Endodontics

Nowadays, we use the term “modern endodontics” thanks to new technologies, novel materials, and revolutionary techniques. Various equipment is available to facilitate and improve our endodontic treatments, such as operating microscopes, ultrasounds, lasers, modern alloys for rotary files, powerful irrigation systems, new materials for filling root canals, 3D radiology, and several more. With the aid of the previously mentioned advances, complex endodontic treatments can be carried out safely, hence guaranteeing patients a high level of care and, above all, saving teeth that would otherwise be doomed for extraction. General practitioners and, even more importantly, specialists in endodontics should implement these modern technologies in their practice. This Special Issue will focus on modern endodontics regarding all the recent updates. Full papers of original articles, short communications, and review articles are all invited

Human Teeth

This book provides information on nomenclature, tooth numbering systems, tooth morphology, and anatomy and stages of tooth formation. It continues with root canal morphology and anatomy of incisors, canines, premolars, and molars. External and internal anatomies of mandibular permanent incisors and maxillary permanent first molars are presented according to a literature review. Orofacial structures affecting tooth morphology are discussed in detail. The book ends with the evolution of dental implant shapes and today�s custom root analog implants

Human fetal whole-body postmortem microfocus computed tomographic imaging

Perinatal autopsy is the standard method for investigating fetal death; however, it requires dissection of the fetus. Human fetal microfocus computed tomography (micro-CT) provides a generally more acceptable and less invasive imaging alternative for bereaved parents to determine the cause of early pregnancy loss compared with conventional autopsy techniques. In this protocol, we describe the four main stages required to image fetuses using micro-CT. Preparation of the fetus includes staining with the contrast agent potassium triiodide and takes 3–19 d, depending on the size of the fetus and the time taken to obtain consent for the procedure. Setup for imaging requires appropriate positioning of the fetus and takes 1 h. The actual imaging takes, on average, 2 h 40 min and involves initial test scans followed by high-definition diagnostic scans. Postimaging, 3 d are required to postprocess the fetus, including removal of the stain, and also to undertake artifact recognition and data transfer. This procedure produces high-resolution isotropic datasets, allowing for radio-pathological interpretations to be made and long-term digital archiving for re-review and data sharing, where required. The protocol can be undertaken following appropriate training, which includes both the use of micro-CT techniques and handling of postmortem tissue

The influence of different irrigation regimes on the cleanliness and physical properties of the root canal walls

PhD ThesisThis thesis describes a series of investigations into the effects of root canal irrigants on dental root dentine. Imaging of human, ovine and bovine root dentine revealed no significant differences in tubule density or diameter. Canal volumes were estimated to be significantly different between human and bovine, but not between human and ovine teeth. EDAX identified significant differences in Ca/P ratios between ovine and bovine, and between ovine and human dentine at points up to 300μm from the root canal lumen. The Ca/P ratio of bovine dentine was significantly lower than human at the canal lumen only. Atomic Force Microscopy (AFM) revealed human and bovine root dentine to be significantly stiffer than ovine dentine at all depths from the canal lumen; human root dentine was stiffer than bovine dentine up to 300μm from the lumen. Animal teeth were concluded to be imperfect replacements for human teeth in endodontic research. Serial polishing down to 0.05μm aluminium oxide was refined for the gentle removal of laboratory-generated smear layers from sectioned dentine specimens, allowing analysis of subtle surface and sub-surface changes following exposure to root canal irrigants, and AFM analysis of smooth, flat dentine surfaces. A new 5-point scale was developed for scoring root canal cleanliness. NaOCl (5% & 10%) removed pulpal debris and predentine from canal walls after 5 minutes exposure at room temperature, with no evidence of chemical etching (score 4). NaOCl (2.5%) also resulted in a score of 4 in the coronal third, although in middle and apical thirds it was less effective (score 3). AFM analysis revealed no change in surface or sub-surface dentine stiffness after exposure to NaOCl, (5% & 10%, 5 minutes). Significant changes in dentine stiffness after exposure to 17% EDTA and 6% citric acid for 1 minute, were not increased after 2 minutes exposure.Iraqi Embassy, Ministry of Higher Education, the Post Graduate Office and the ICM uni

Development of a model to assess cleaning and disinfection of complex root canal systems

The remaining debris and biofilm in the anatomical complexities of root canal systems can affect treatment outcomes. Files with asymmetric cross-section design may improve debris and biofilm removal from these difficult spaces during canal preparation. Tooth opacity and different densities of the remaining materials prevent the direct systematic assessment of the preparation process. The present study assessed remaining debris and biofilm using a novel transparent root canal model with novel approaches. Natural and simulated root canal samples with isthmus space were evaluated. Canal preparation by ProTaper Next and Revo-S asymmetric systems was evaluated in comparison to the standard ProTaper Universal symmetric system. The root canals were investigated by microcomputed tomography (micro-CTL confocal laser scanning microscopy (CLSML and optical coherence tomography (OCT) imaging tools. Data analysis was undertaken with SPSS (V. 24). Files with asymmetric cross-section and constant taper removed more debris and biofilm from the complex root canal system. The model allowed direct assessment of remaining materials and confirmed the novel imaging approach with the OCT. In conclusion, the asymmetric design improves debris and biofilm removal especially when used with a constant taper. The model was verified as an ideal system for assessing root canal treatment in vitro

Stationary intraoral tomosynthesis imaging for vertical root fracture detection

University of Minnesota M.S. thesis. August 2017. Major: Dentistry. Advisor: Scott McClanahan. 1 computer file (PDF); viii, 168 pages.The purpose of this study was to compare the radiographic detection of induced vertical root fractures among periapical, limited-FOV CBCT, and stationary intraoral tomosythesis imaging, as well as the relationship between these variables and their impact on evaluator confidence in diagnosis of vertical root fractures. Tomosynthesis imaging uses a multi-source X-ray carbon nanotube array that allows for a acquisition of multiple basis images and subsequent reconstruction of a 3D volume. Sixty fully developed extracted human premolar root samples were assigned two one of four groups based on being either obturated or unobturated and fractured or unfractured. Samples were mounted in artificial alveolar bone then imaged with two-dimensional periapical imaging, limited-FOV CBCT, and stationary intraoral tomosynthesis. Three blinded evaluators assessed for the presence of fractures (yes or no) as well as reported a level of confidence (1 through 5). Generalized estimated equations was used to analyze the data. Within the limitations of this study, it can be concluded that stationary intraoral tomosynthesis improves the sensitivity of detection of induced root fractures compared to a single radiograph. Limited-FOV CBCT is the most sensitive imaging modality for detection of fractures among obturated and unobturated root samples. There is no significant difference in specificity or overall accuracy in fracture detection among periapical, CBCT, and tomosynthesis imaging. The presence of obturation material has a statistically significant reduction in sensitivity of fracture detection and accuracy for periapical radiographs. Obturation status did not have a significant impact on sensitivity for tomosynthesis imaging. . Furthermore, tomosynthesis imaging is superior to periapical imaging in root fracture detection insofar as the presence of obturation material does not significantly reduce fracture detection