Mechanism of action of Bioactive Endodontic Materials

Abstract A continuous search for bioactive materials capable of supporting the replacement of damaged pulp tissue, with effective sealing potential and biocompatibility, has represented the attention of studies over the last decades. This study involves a narrative review of the literature developed by searching representative research in PUBMED/MEDLINE and searches in textbooks associated with the mechanism of action of bioactive materials (calcium hydroxide, mineral trioxide aggregate (MTA), and calcium silicate cements). The reflective analysis of the particularities of the chemical elements of these materials, considering the tissue and antibacterial mechanism of action, allows a better understanding of the characteristics and similarities in their tissue responses. Calcium hydroxide paste remains the antibacterial substance of choice as intracanal dressing for the treatment of root canal system infections. Calcium silicate cements, including MTA, show a favorable biological response with the stimulation of mineralized tissue deposition in sealed areas when in contact with connective tissue. This is due to the similarity between the chemical elements, especially ionic dissociation, the potential stimulation of enzymes in tissues, and the contribution towards an alkaline environment due to the pH of these materials. The behavior of bioactive materials, especially MTA and the new calcium silicate cements in the biological sealing activity, has been shown to be effective. Contemporary endodontics has access to bioactive materials with similar properties, which can stimulate a biological seal in lateral and furcation root perforations, root-end fillings and root fillings, pulp capping, pulpotomy, apexification, and regenerative endodontic procedures, in addition to other clinical conditions.

Resumo Uma busca contínua de materiais bioativos com capacidade de substituir o tecido pulpar danificado, com efetiva capacidade de selamento e biocompatibilidade, tem representado a atenção e foco de muitos estudos ao longo das últimas décadas. Este estudo envolve uma revisão narrativa da literatura desenvolvida por meio de pesquisas representativas encontradas no PUBMED/MEDLINE e pesquisas em livros didáticos associadas ao mecanismo de ação de materiais bioativos (hidróxido de cálcio, agregado de trióxido mineral (MTA) e cimentos de silicato de cálcio). A presente análise reflexiva das particularidades dos elementos químicos destes materiais bioativos, considerando o mecanismo de ação tecidual e antibacteriano, possibilita um melhor entendimento das características e similaridades no comportamento tecidual. A pasta de hidróxido de cálcio continua sendo a substância antibacteriana de escolha como medicação intracanal para o tratamento das infecções do sistema de canais radiculares. Este fato se deve a disponibilidade química de íons cálcio e hidroxila do hidróxido de cálcio aos tecidos, e a inibição enzimática bacteriana. Os cimentos de silicato de cálcio, dentre os quais inclui o MTA, apresentam uma resposta biológica favorável ao estímulo à deposição de tecido mineralizado nas áreas seladas e em contato com tecido conjuntivo. Este fato é decorrente da similaridade entre os elementos químicos, em especial devido a dissociação iônica, ao potencial estímulo de enzimas teciduais, e a contribuição com um meio alcalino decorrente do pH destes materiais. O comportamento dos materiais bioativos, em especial o MTA e os novos cimentos de silicato de cálcio na atividade de selamento biológico mostraram efetivos. A endodontia contemporânea atualmente conta com o potencial de materiais bioativos com propriedades análogas capaz de estimular o selamento biológico em perfurações radiculares laterais e de furca, em obturações radiculares, capeamento pulpar, pulpotomia, apicificação e procedimentos endodônticos regenerativos, além de outras condições clínicas.

Method to determine the root canal spatial geometry using an algorithm of the e-Vol DX CBCT software

Abstract This study evaluated a method to determine the spatial geometry of root canal preparation (RCP) using navigation dynamics and a specific algorithm from a new CBCT software (e-Vol DX). CBCT scans of 168 root canals of mandibular molars were acquired before and after RCP, using nickel-titanium (NiTi) instruments (ProTaper Next, BioRace, Reciproc Blue, and WaveOne Gold). The spatial geometry of the root canals and the operative risk of disproportional wear of dentinal walls after RCP were evaluated using a new CBCT software. A 3-point scoring system was used after the measuring of cementum/dentin thickness before and after RCP in all root thirds. The root thirds were distributed into three parts of similar sizes, and the scores were categorized at three levels: 1. mild risk (1/3), 2. moderate risk (2/3), 3. severe risk (3/3). These levels were proposed according to the risk of creating disproportionate shapes, thin walls, or perforations. The data were analyzed statistically by Fischer's exact test (α = 5%). There were no significant differences in operative risk among the NiTi engine-driven systems, for the distal or mesial walls of all the root canal thirds (p>0.05). The spatial geometry method to assess operative risk allows clinical planning for a predictable enlargement of the root canal in all root thirds. Based on using a map-reading strategy on root canals in CBCT scans, NiTi engine-driven instruments did not present an increased operative risk during RCPs.

Resumo Este estudo avaliou um método para determinar a geometria espacial do preparo do canal radicular (PCR) usando uma dinâmica de navegação e um algoritmo específico do software e-Vol DX. Imagens de tomografia computadorizada de feixe cônico (TCFC) de 168 molares inferiores foram adquiridas antes e depois do PCR, usando instrumentos de níquel-titânio (NiTi) (ProTaper Next, BioRace, Reciproc Blue e WaveOne Gold). A geometria espacial dos canais radiculares e o risco operatório de desgaste desproporcional das paredes dentinárias após o preparo foram avaliados usando o software de TCFC e-Vol DX. Um sistema de Score de 3 pontos foi usado após a mensuração da espessura cemento/dentina antes e depois do PCR, em toda extensão dos canais radiculares. Os terços radiculares foram distribuídos em três partes de tamanhos semelhantes, e os Scores foram categorizados em três níveis: 1. risco leve (1/3), 2. risco moderado (2/3), 3. risco severo (3/3). Esses níveis foram propostos de acordo com o risco de criar formas desproporcionais, paredes finas ou perfurações radiculares. Os dados foram analisados estatisticamente pelo teste exato de Fischer ((=5%). Não houve diferenças significativas no risco operatório entre os sistemas de NiTi acionados a motor, para as paredes distal ou mesial em todos os terços do canal radicular (p>0,05). O método de geometria espacial para avaliar o risco operatório permite o planejamento clínico para um alargamento previsível do canal radicular em todos os terços radiculares. Com base no uso de uma estratégia de navegação dinâmica de canais radiculares de molares inferiores analisados em imagens de TCFC, os instrumentos de NiTi acionados estudados não apresentaram um aumento do risco operatório durante o preparo dos canais radiculares.

Evaluation of the expression of nerve fiber markers in healthy and inflamed dental pulp

Abstract The diagnosis of irreversible pulpitis (IP) depends on clinical data, especially the chief complaint of the patient, visual inspection, response to the application of stimuli, and radiographic examination. The characterization of nerve fibers (NF) in IP may contribute to better interpret painful symptoms, but has been barely explored. This study sought to characterize the density and integrity of NF in 16 samples of IP and in five healthy pulps (HP) using S-100 and PGP 9.5 markers. Immunohistochemistry was performed to determine the density/mm2 of S-100+ and PGP 9.5+ in NF. The amount of degenerated NF was obtained by subtracting the total NF density from the amount of intact NF. Associations between NF density and integrity and symptomatology were calculated. All samples were positive for S-100 and PGP 9.5. Compared to HP samples (38.20/mm2), IP samples had a lower density of intact NF (6.24/mm2). A significantly higher density of degenerated NF was found in IP samples with spontaneous pain (39.59/mm2) compared to those with provoked pain (23.96/mm2) (p = 0.02). No association was observed between intensity of the inflammatory infiltrate and NF density and integrity (p > 0.05). The findings of this study suggest that pulpitis may involve different stages of degeneration and may be more advanced in cases with spontaneous pain. The symptoms reported by affected individuals do not appear to depend on the intensity of the inflammatory infiltrate, but rather on the integrity of NF.

Does radiotherapy treatment alter the pulp condition in patients with head and neck cancer? A systematic review

Abstract The main purpose of this study was to answer the question: "Can radiotherapy cause changes in the dental pulp condition of patients treated with irradiation in the head and neck region?" Clinical observational studies in adults with head and neck cancer undergoing treatment with ionizing radiation, longitudinal or cross-sectional follow-up to measure oxygen saturation (SpO2), and/or pulp sensitivity test to cold stimulation, were considered eligible. A systematic literature search was performed in six different databases, including the gray literature, and in article references. Two independent evaluators selected the studies, extracted the data, recorded the data on electronic spreadsheets, and then evaluated the methodological quality using the Checklist for Quasi-Experimental Studies tool devised by JBI. The data were assessed qualitatively using the Synthesis Without Metanalysis (SWiM) guidelines. After removing the duplicate articles, carefully analyzing the titles and abstracts, and reading the papers in full, seven studies were included. Four of the studies evaluated applied the cold sensitivity test, two associated pulse oximetry and cold sensitivity, and only one used just pulse oximetry. Evaluation using the cold sensitivity test and pulse oximetry in the initial periods before radiotherapy showed a decrease in the sensitive response and in SpO2 levels during a maximum period of 1 year. However, analyses thereafter indicated a normal response in both tests from 5 to 6 years after the end of radiotherapy treatment. Radiotherapy causes changes in pulp behavior patterns in the short term; however, recovery and return to average values occurs after long periods.

Effect of low-power diode laser on infected root canals

Abstract This study evaluated the effect of photodynamic therapy (PDT) on infected root canals. Twenty-one human teeth were selected, and 18 were infected by E. faecalis for 60 days. The antimicrobial strategies tested were: G1. Root canal preparation (RCP) using Niquel-Titanium (NiTi) rotary instruments, 2.5% NaOCl, and final irrigation with 17% EDTA, followed by PDT with methylene blue photosensitizer and laser diode low power; G2. RCP using stainless steel files and the same irrigation and PDT protocols as G1; G3. Same RCP protocol as G1 without PDT; G4. Only irrigation with 2.5% NaOCl; G5. Same PDT protocol as G1 without RCP; G6. Negative control; G7. Positive control. Samples for microbiological tests were collected initially (S1), after RCP (S2), and after PDT (S3). Subsequently, the roots were sectioned and prepared for Scanning Electron Microscopy (SEM) analysis. Bacterial growth was analyzed according to the turbidity of the culture medium, followed by spectrophotometric optical density (nm). The effect of PDT on the dentinal structure was evaluated at magnifications 1,600X and 5,000X and described qualitatively. The Wilcoxon test was used for the comparisons from the same specimens, and the Mann-Whitney test was used to compare groups ((=5%). Bacteria were found in all experimental groups' microbiological samples (S1, S2 and S3). The optical density of culture media was lower in S2 than in S1 of G1, 2, 3, and 4 (p> 0.05). After PDT (S3) in G1 and 2, there was an additional reduction in optical density of the culture medium, respectively (p>0.05). In Group 5, the analysis of culture media at S2 revealed an increase in optical density compared to S1(p>0.05). In SEM images of G1, 2, and 5, dentin with melting and recrystallization areas were evidenced. After preparation of the root canal with the rotary system or manually associated with 2.5% NaOCl, PDT was not able to completely eliminate E. faecalis present in the root canal.

Resumo Este estudo avaliou o efeito da terapia fotodinâmica (PDT) em canais radiculares infectados com E. faecalis. Vinte e um dentes humanos extraídos foram selecionados, e 18 foram infectados por E. faecalis por 60 dias. As estratégias antimicrobianas testadas foram: G1. Preparo do canal radicular (PCR) com instrumentos rotatórios de NiTi, NaOCl 2,5% e irrigação final com EDTA 17%, seguido de PDT com fotossensibilizador azul de metileno e laser diodo de baixa potência; G2. PCR usando limas de aço inoxidável e os mesmos protocolos de irrigação e PDT do G1; G3. Protocolo de PCR similar que G1 sem PDT; G4. Somente irrigação com NaOCl 2,5%; G5. Protocolo similar ao G1, sem PCR; G6. Controle negativo; G7. Controle positivo. Amostras para exames microbiológicos foram coletadas inicialmente (S1), após PCR (S2) e após PDT (S3). Na sequência, as raízes foram seccionadas e preparadas para análise em microscopia eletrônica de varredura (MEV). O crescimento bacteriano foi analisado de acordo com a turbidez do meio de cultura seguida pela densidade óptica espectrofotométrica (nm). O efeito da PDT na estrutura dentinária foi avaliado em aumentos de 1.600X e 5.000X, e descrito qualitativamente. O teste de Wilcoxon foi utilizado para as comparações dos mesmos espécimes e o teste de Mann-Whitney para as comparações entre os grupos ((=5%). Bactérias foram encontradas em todos os grupos experimentais, e em todas as coletas microbiológicas (S1, S2 e S3). A densidade óptica dos meios de cultura foi menor em S2 do que em S1 de G1, 2, 3 e 4 (p>0,05). Após a PDT (S3) em G1 e 2, houve redução adicional na densidade óptica do meio de cultura de 90,0% e 92,0%, respectivamente (p>0,05). No Grupo 5, a análise dos meios de cultura em S2 revelou um aumento de 3,2% na densidade óptica em comparação com S1(p>0,05). Nas imagens de MEV do G1, 2 e 5 foram evidenciadas dentina com áreas de fusão e recristalização. O PDT utilizado após preparo do canal radicular com sistema rotatório ou manual, associado ao NaOCl 2,5%, não foi capaz de eliminar completamente o E. faecalis em biofilme maduro presente no canal radicular.

A computational modeling method for root canal endoscopy using a specific CBCT filter: A new era in the metaverse of endodontics begins

Abstract A contemporary technological revolution has started a new era in the metaverse of Endodontics, a world of virtual operational possibilities that use an exact replica of the natural structures of the maxillofacial complex. This study describes a modeling method for root canal endoscopy using modern cone-beam CT (CBCT) software in a series of clinical cases. The method consists in acquiring thin CBCT slices (0.10mm) in the coronal, sagittal, and axial planes. A specific 3D volume filter, the pulp cavity filter of the e-Vol DX CBCT software, was used to navigate anatomical root canal microstructures, and to scan them using root canal endoscopy. The pulp cavity filter should be set to synchronize CBCT scans from 2D mode - multiplanar reformations (MPR) - to 3D mode - volumetric reconstruction. This filter, when adopting the option of volumetric reconstruction, the developed algorithm leaves the dentin density in transparent mode so that the pulp cavity may be visualized. The algorithm applied performs the suppression (visual) of areas with dentin density. This ensures 3D visualization of the slices and the microanatomy of the root canal, as well as a dynamic navigation throughout the pulp cavity. This computational modeling method adds new resources to Endodontics, which may impact the predictability of root canal treatments positively. The virtual visualization of the internal anatomy of an exact replica of the canal ensures better communications, reliability, and clinical operationalization. Root canal endoscopy using this novel CBCT filter may be used for clinical applications together with innovative digital and virtual-reality resources that will be naturally incorporated into the principles of Endodontics.

Resumo Uma revolução tecnológica contemporânea deu início a uma nova era no metaverso da Endodontia, um mundo de possibilidades operacionais virtuais que utilizam uma réplica exata das estruturas naturais do complexo dentomaxilofacial. Este estudo descreve um método de modelagem computacional para a endoscopia do canal radicular, usando um moderno software de tomografia computadorizada de feixe cônico (TCFC), em uma série de casos clínicos. O método consiste na aquisição de finos slices de TCFC (0,10mm) nos planos coronal, sagital e axial. Um filtro específico de TCFC (filtro cavidade pulpar do software e-Vol DX) foi usado para navegar nas microestruturas anatômicas do canal radicular, e escanear para a aplicação da endoscopia do canal radicular. Este filtro foi configurado para sincronizar as imagens de TCFC em modo 2D - reformações multiplanares (MPR) para o modo 3D - reconstrução volumétrica. O filtro Pulp Cavity ao adotar a opção de reconstrução volumétrica, um algoritmo desenvolvido deixa a densidade dentinária em modo transparente, para que a cavidade pulpar possa ser melhor visualizada. O algoritmo aplicado realiza a supressão (visual) das áreas com densidade dentinária. Este modo de aplicação garante a visualização 3D da microanatomia do canal radicular, bem como permite uma navegação dinâmica por toda a cavidade pulpar. O método de modelagem computacional agrega novos recursos à Endodontia, o que pode impactar positivamente na previsibilidade dos tratamentos endodônticos. A visualização virtual da anatomia interna de uma réplica exata do canal radicular garante melhor comunicação, confiabilidade e operacionalização clínica. O exame de endoscopia do canal radicular com este novo filtro (Pulp cavity) pode ser usada para aplicações clínicas juntamente com recursos digitais e de realidade virtual inovadores que serão naturalmente incorporados aos princípios da Endodontia.

Evaluation in the danger zone of mandibular molars after root canal preparation using novel CBCT software

Abstract: This study measured the thickness of cementum/dentin in the danger zone of the mandibular molars after root canal preparation using novel cone-beam computed tomography (CBCT) software. Eighty-four teeth were distributed into four groups: ProTaper Next, BioRace, Reciproc Blue, and WaveOne Gold. E-Vol DX® CBCT software was used to measure initial and final remaining cementum-dentin thicknesses after root canal preparation of the mesial root of mandibular molars at 1 and 3 mm from the furcation. The Kolmogorov-Smirnov test was used to test variable symmetry. The variables were described as mean and standard deviations, compared among the groups using analysis of variance (ANOVA), and within the groups using the Student t test. A generalized estimating equation model was used to compare the variation before and after root canal preparation. The level of significance was set at 5%. Differences between mean initial and final thicknesses of the mesiobuccal (MB) and mesiolingual (ML) canals were not statistically significant. The mean initial thickness was 3 mm (0.900 mm ± 0.191), considering that a mean lower than 1 mm (1.035 mm ± 0.184) indicates the danger zone. Although cementum/dentin is thinner at 3 mm from the furcation (0.715±0.186) after root canal preparation, the greatest amount of dentin removed was found at 1 mm (0.734 ± 0.191). The cementum-dentin remaining after preparation was thicker than 0.715 mm in root canals prepared using #35 (WaveOne Gold®) and #40 (ProTaper Next®, BioRace® and Reciproc Blue®) instruments. This confirms the safety of canal preparation in the danger zone using these systems.

Selamento de perfuração radicular associado a enxerto de tecido conjuntivo em área estética: relato de caso / Sealing of root perforation associated with connective tissue graft in aesthetic area: Case report

Introdução: Perfuração radicular é a comunicação entre as paredes do canal radicular e o espaço periodontal. O tempo, a localização e a dimensão da perfuração são fatores que afetam no prognóstico do dente. Objetivo: Relatar um caso clínico de tratamento de perfuração radicular supraóssea associado a enxertia de tecido conjuntivo em área estética. Relato do caso: Paciente relatou ter sido submetido, há 3 meses, ao tratamento endodôntico do dente #22; porém, esse não foi finalizado. Ao exame clínico, o dente apresentava ausência de dor e presença de fístula na região da gengiva inserida. As imagens radiográficas e tomográficas revelaram imagem sugestiva de perfuração radicular na região vestibular do dente #22, além de área hipodensa/radiolúcida circunscrita ao ápice radicular, conduzindo ao diagnóstico de periodontite apical assintomática associada a perfuração radicular supraóssea. Inicialmente, foi realizado preparo do canal radicular e utilizada medicação intracanal por 21 dias. Posteriormente, foi realizada a obturação do canal radicular e restauração definitiva em resina composta na face palatal. Na mesma sessão, foi realizado o acesso cirúrgico para selamento da perfuração com resina composta, associado a enxertia de tecido conjuntivo no dente #22, para evitar recessão tecidual marginal. Foi observada, após 12 meses, neoformação óssea na região periapical do dente #22, com ausência de dor e preservação da estética na região periodontal. Conclusão: O diagnóstico e o planejamento multidisciplinar são fatores importantes no tratamento de perfurações radiculares, assim como a correta escolha do material selador (AU).

Introduction: Root perforation is the communication between the walls of the root canal and the periodontal space. The time, location and size of the perforation are factors that affect the prognosis of the tooth. Objective: To report a clinical case of treatment of supraosseous root perforation associated with grafting of connective tissue in aesthetic area. Case report: Patient reported that 3 months had started root canal treatment of tooth 22, but was not finalized. At the clinical examination, the tooth presented absence of pain and presence of sinus tract in the region of attached gingiva. Radiographic and tomographic images revealed an image suggestive of root perforation in the buccal region of tooth 22, as well as a hypodense / radiolucent area circumscribed to the root apex, leading to the diagnosis of asymptomatic apical periodontitis associated with supraosseous root perforation. Initially, it were performed root canal preparation and intracanal medication. After 21 days, root canal obturation and composite restoration were performed on the palatal face. In the same session, the surgical access was made to sealing the perforation with composite resin, associated to the grafting of connective tissue in tooth 22, to avoid marginal tissue recession. It was observed after 12 months new bone formation in the periapical region of tooth 22, with absence of pain and preservation of aesthetics in the periodontal region. Conclusion: Multidisciplinary diagnosis and planning are important factors in the treatment of root perforations, as well as the correct selection of materials used to seal root perforations (AU).

Method to Identify Accessory Root Canals using a New CBCT Software

Abstract This study describes a methodology to identify accessory root canals using the e-Vol DX software in CBCT scans. Accessory root canals are strategic shelters for microorganisms present in root canal infections. The identification of these small canals in periapical radiographic exams has limitations, besides being markedly limited accessibility to the action of endodontic instruments and to the antimicrobial agents. A significant number of accessory canals have sufficient diameters to be visible on cone-beam computed tomography (CBCT) images of high spatial resolution. Therefore, it may go unnoticed or even confused when there is no specific training for this type of diagnosis. The methodology consists in establishing thin slices (0.1mm or smaller) obtained from coronal, sagittal and axial slices. The method consists of the following steps: during navigation along the long axis of a root canal when finding a possible hypodense line of main root canal in a tomographic section (axial, sagittal or coronal), the navigation software lines of the multiplanar reconstruction (MPR) must be adjusted so that they are parallel and perpendicular to the hypodense line (parallax correction). Then, after judiciously adjusted, the accessory canal image will invariably appear as a line on one of the MPR tomographic slices, another line on another slice, and a dot on the third slice. The three sections of the MPR present images with the "line-line-dot" sequence. In this way, it is possible to identify an accessory root canal and also visualize it in volumetric reconstruction in a specific filter. The application of this method is easy to employed and may benefit the diagnosis when you want to visualize accessory root canals and distinguish it from root fracture line.

Resumo Este estudo descreve um método para identificar canais radiculares acessórios usando o software e-Vol DX em imagens de TCFC. Os canais radiculares acessórios constituem abrigos estratégicos aos micro-organismos presentes nas infecções endodônticas. A identificação destes pequenos canais em exames radiográficos periapicais apresenta limitações, além de apresentar baixa acessibilidade natural a ação dos instrumentos endodônticos e dos agentes antimicrobianos. Os canais acessórios apresentam diâmetros suficientes para ficarem visíveis em imagens de tomografia computadorizada de feixe cônico (TCFC) de alta resolução espacial. Porém, podem passar despercebidos ou até confundidos quando não ocorrer treinamento específico para este tipo de diagnóstico. A metodologia consiste em estabelecer finos slices (0,1 mm ou menor) obtidos a partir de cortes coronal, sagital e axial. O método consiste nos seguintes passos: ao encontrar uma linha hipodensa de um canal radicular principal em um corte tomográfico (axial, sagital ou coronal) deve-se ajustar as linhas de navegação da reconstrução multiplanar (MPR) para que fiquem paralelas ao canal principal e perpendiculares a esta linha hipodensa (correção de paralaxe). A seguir, depois de criterioso ajuste da imagem em busca do canal acessório, aparece invariavelmente como uma linha em um dos cortes tomográficos da MPR, outra linha em outro corte e um ponto no terceiro corte. Os três cortes da MPR apresentam imagens com a sequência linha-linha-ponto. Desta maneira, pode-se identificar um canal acessório e visualizá-lo em reconstrução volumétrica em filtro específico. Esta metodologia é fácil de ser aplicada e pode beneficiar o diagnóstico quando se deseja identificar canais radiculares acessórios e distingui-lo de linha de fratura radicular.

Digital Planning on Guided Endodontics Technology

Abstract The aim of this review is to discuss the digital planning and the use of guided technology in Endodontics. The complexity of the root canals anatomy and the challenges in the microorganism's control represent risk factors for failure after the infected root canal's treatment. Scientific improvements associated with technological advances have enabled better predictability of therapeutic procedures results. The development of efficient and modern devices provided safer root canal treatments, with shorter clinical visits and greater patient comfort. Digital endodontics incorporated different tools and developed its own, advancing even further in resolving complex cases. The faithful copy of the internal anatomy provided by the advancement of CBCT devices and software's, associated with the digital resources of 3D planning and printing, enabled the advent of guided endodontics. This technique is used at different stages of endodontic treatment, with specific indications and greater result predictability. Therefore, this study critically reviewed the potential clinical application of this guided access technique, and the operative steps for its safe performance in managing complex endodontic cases. The main indications are accessing calcified root canals, performing endodontic surgeries in difficult access areas, removing fiberglass posts, and accessing teeth with developmental anomalies. In summary, guided endodontics has been a precise strategy, effective, safe, and clinically applicable. This procedure represents incorporating technological resources and digital planning in the Endodontist clinical practice, increasing predictability to complex cases.

Resumo O objetivo desta revisão é discutir o planejamento digital e o uso da tecnologia guiada em Endodontia. A complexidade e variabilidade da anatomia dos canais radiculares, em conjunto com o desafio no processo de sanificação e controle de micro-organismos representam fatores de risco ao fracasso após o tratamento dos canais radiculares infectados. O aprimoramento técnico-científico e os avanços tecnológicos tem possibilitado uma melhor previsibilidade de resultados nos procedimentos terapêuticos. O desenvolvimento de ferramentas de trabalho eficientes e modernas proporcionou tratamentos endodônticos seguros, com menor tempo clínico operacional e maior conforto ao paciente. A endodontia digital incorporou diferentes ferramentas e desenvolveu suas próprias, avançando ainda mais na resolução de casos complexos. A cópia fiel da anatomia interna proporcionada pelo avanço dos aparelhos e softwares de TCFC, associada aos recursos digitais de planejamento e impressão 3D possibilitaram o surgimento da endodontia guiada. Esta técnica é utilizada em diferentes etapas do tratamento endodôntico, com indicações específicas e maior previsibilidade de resultados. Este estudo revisou criticamente o potencial de aplicação clínica da técnica de acesso guiado, e os passos operatórios para sua realização de forma segura no manejo de casos endodônticos complexos. As principais indicações da Endodontia Guiada incluem o acesso a canais radiculares calcificados; as cirurgias parendodônticas em áreas de difícil acesso; a remoção de pinos de fibra de vidro; e o acesso a dentes com anomalias de desenvolvimento. Em síntese, a endodontia guiada é uma técnica precisa, eficaz e de fácil aplicação clínica. Esta técnica representa a incorporação dos recursos tecnológicos e planejamentos digitais do Endodontista, dando maior previsibilidade aos casos em que é aplicada na prática clínica.

A Critical Review of the Differential Diagnosis of Root Fracture Line in CBCT scans

Abstract The objective of this critical review of literature is to discuss relevant clinical factors associated with root fractures (RF) visualized by using a new CBCT software. RF constitutes a common occurrence and a challenge in clinical practice, in which the diagnosis becomes essential for the definition of rapid and precise decision-making. The characterization of RF may involve different aspects, such as orientation of the fracture line (horizontal, vertical, oblique), root position of the fracture (cervical, middle, apical third), fracture's coronal-radicular position (coronary, coronal-radicular, radicular), continuity of the fracture (crack, incomplete fracture, complete), bone extension of the fracture (supraosseous, bone level, infraosseous fracture). Imaging examinations have been routinely used to aid in the RF diagnosis. Even with high-resolution cone-beam computed tomography (CBCT) scans, many doubts often remain about the diagnostic outcome. Many interferences in the analysis of image quality to determine the diagnosis are identified, such as the sharpness, the noise, light and dark artifacts, among others. The professional's knowledge is essential for identifying the different patterns of fracture lines and their repercussions on adjacent bone tissues, as well as for the analysis of artifacts that may hide or show similarities to fracture lines. Fractures lines and root fractures that may be associated with phantom conditions that mimic fractures should be carefully analyzed. CBCT is the exam indicated to identify a root fracture. It is also added to the success of the diagnosis that the professional has scientific knowledge, training and mastery of advanced CBCT software.

Resumo O objetivo desta revisão crítica da literatura é discutir os fatores clínicos relevantes associados às fraturas radiculares FR visualizados por meio de um novo software de CBCT. As fraturas radiculares constituem uma ocorrência comum e um desafio na prática clínica, em que o diagnóstico torna-se essencial para a definição de uma tomada de decisão rápida e precisa. A caracterização da FR pode envolver diversos aspectos, como orientação da linha de fratura (horizontal, vertical, oblíqua), posição radicular da fratura (cervical, médio, apical), posição coronoradicular da fratura (coronária, coronorradicular, radicular), continuidade da fratura (trinca, fratura incompleta, completa), extensão óssea da fratura (supraóssea, nível ósseo, fratura infraóssea). Os exames de imagens têm sido usados ​​rotineiramente para auxiliar no diagnóstico de RF. Mesmo com a tomografia computadorizada de feixe cônico (TCFC) de alta resolução, muitas vezes permanecem muitas dúvidas sobre o resultado do diagnóstico. São identificadas muitas interferências na análise da qualidade da imagem para determinar o diagnóstico, como a nitidez, o ruído, artefatos claros e escuros, dentre outros. O conhecimento do profissional é fundamental para identificar os diferentes padrões de linhas de fraturas e suas repercussões nos tecidos ósseos adjacentes, bem como para a análise de artefatos que podem ocultar ou apresentar semelhanças com as linhas de fraturas. As linhas de fraturas e fraturas radiculares que podem estar associadas às condições fantasmas que mimetizam fraturas devem ser analisadas cuidadosamente. A TCFC constitui o exame por imagem indicado para identificar uma fratura radicular. Acrescenta-se ao sucesso do diagnóstico o fato do profissional apresentar conhecimento científico, treinamento e domínio de softwares avançados de TCFC.

Accuracy of periapical and panoramic radiography for detection of root morphologies: a comparative study

Abstract: Maxillary and mandibular incisors have increased risk for severe orthodontically induced inflammatory root resorption. A patient-related risk factor is aberrant root morphology. This study aimed to assess the frequency of detection of different root morphologies in anterior teeth using dental panoramic tomography (DPT) and long cone periapical radiographs (LCPAs). A retrospective cross-sectional design was used to assess a sample of 50 consecutive pre-treatment radiographic records of patients from a specialist orthodontic practice in Adelaide, Australia. A reference guide was developed that included three previously unreported morphologies: pipette and bent, bent and pointed, bent and blunt. Two trained and calibrated assessors examined each record against the inclusion criteria, then independently assessed each anterior tooth from DPTs and LCPAs to detect the type of root morphology present. Data were analysed using the chi-square statistical test. Radiographic records for 48 patients (48 DPTs and 161 LCPAs) were eligible, with 355 and 426 teeth on DPTs and LCPAs, respectively, included for assessment. Normal root morphology (119 teeth) was commonly observed in DPTs, while bent (154 teeth) was frequently observed using LCPAs. Mandibular incisors often had normal morphology in DPTs but bent in LCPAs. Bent was the most common morphology in maxillary lateral incisors using DPT and LCPAs, although maxillary centrals were mostly normal in DPTs but pointed in LCPAs. Differences using the two image acquisition methods were highly significant (p < 0.01). Aberrant root morphologies are more easily detected in anterior teeth using LCPAs compared to DPTs.

Cone-beam computed tomography cinematic rendering: clinical, teaching and research applications

Abstract Cone-beam computed tomography (CBCT) is an essential imaging method that increases the accuracy of diagnoses, planning and follow-up of endodontic complex cases. Image postprocessing and subsequent visualization relies on software for three-dimensional navigation, and application of indexation tools to provide clinically useful information according to a set of volumetric data. Image postprocessing has a crucial impact on diagnostic quality and various techniques have been employed on computed tomography (CT) and magnetic resonance imaging (MRI) data sets. These include: multiplanar reformations (MPR), maximum intensity projection (MIP) and volume rendering (VR). A recent advance in 3D data visualization is the new cinematic rendering reconstruction method, a technique that generates photorealistic 3D images from conventional CT and MRI data. This review discusses the importance of CBCT cinematic rendering for clinical decision-making, teaching, and research in Endodontics, and a presents series of cases that illustrate the diagnostic value of 3D cinematic rendering in clinical care.

Aplicação de um novo software de TCFC com filtros específicos para redução de artefatos: série de casos / Application of a new CBCT software with specific filters for blooming artifact reduction: case series

Introdução: As obturações dos canais radiculares e os pinos intrarradiculares geralmente produzem artefatos de contraste branco e possíveis alterações volumétricas nas imagens de tomografia computadorizada de feixe cônico (TCFC). Esses artefatos, induzidos pela maior densidade dos materiais obturadores de canais radiculares, cimentos para colocação de coroa e pinos intracanais, podem potencialmente levar a interpretações incorretas, interferindo no diagnóstico de um volume adquirido de TCFC, principalmente na avaliação de potenciais fraturas e perfurações radiculares. Objetivos: Avaliar em seis casos clínicos os efeitos positivos e negativos dos artefatos de contraste branco no diagnóstico de fraturas radiculares, perfurações radiculares e cimentação de restaurações de porcelana. Métodos: O software e-Vol DX, que possui filtros específicos para redução de artefato de contraste (BAR, Blooming Artifact Reduction), foi usado para melhorar o valor diagnóstico dos volumes adquiridos de TCFC. Conclusões: O em- prego do software e-Vol DX para a reconstrução de imagens de TCFC melhorou a visualização das estruturas anatômicas e reduziu os artefatos. A visualização aprimorada de da- dos nas imagens pode auxiliar na identificação de detalhes essenciais que, em conjunto com os achados clínicos, são úteis para uma correta estruturação do diagnóstico (AU).

Introduction: Root canal fillings and intraradicular posts often create white contrast artifacts and possible volumetric changes on CBCT scans known as blooming artifacts. These alterations could lead to the incorrect interpretations reducing the diagnostic of an acquired CBCT volume, particularly when evaluating potential root fractures and root perforations. Methods and Results: In six clinical cases, the positive and negative effects of beam hardening artifacts on the diagnosis of root fractures, root perforations and porcelain restoration cementation were evaluated. These artifacts, induced by the higher density of root canal filling materials, cements for crown placement and intracanal posts, may potentially lead to inaccurate or false interpretations. A novel software, e-Vol DX, which has specific filters for blooming artifact reduction (BAR), was used to improve the diagnostic value of acquired CBCT volumes. Conclusions: The use of the e-Vol DX software package for the reconstruction of CBCT scans improved visualization of anatomical structures and reduced blooming artifacts. Improved data visualization may help reveal essential details that, in conjunction with clinical findings, are useful to achieve a correct diagnosis (AU).

Potential of a new cone-beam ct software for blooming artifact reduction

Abstract This study evaluated the dimensions of intraradicular posts using a new cone beam CT (CBCT) software, and verified the potential of blooming artifact reduction. Sixty-three single-rooted human teeth were shaped, obturated, prepared for intracanal post placement and distributed into three groups: G1: anatomically customized prefabricated glass fiber posts; G2: low-fusion alloy posts; G3: gold alloy posts. After post fabrication and luting with RelyX U200®, specimens were sectioned axially at 9 mm from the root apex, and markings were made on the root surfaces (X-, Y- and Z-axes). The dimensions of the original posts (control group) were measured using a digital micrometer. CBCT scans of the teeth were obtained using a PreXion 3D Elite® scanner. Posts were measured on CBCT scans using DICOM files and the e-Vol DX software. A specific filter, Blooming Artefact Reduction (BAR), was developed to analyze intracanal posts. Statistical data were evaluated using the Van de Waerden nonparametric analysis of variance and, after that, normalized data were analyzed using the Tukey test. The level of significance was set at α = 5%. The measures of the anatomical prefabricated, low-fusion alloy and gold alloy intracanal posts obtained using the e-Vol DX CBCT software and a micrometer were not significantly different (p>0.05). The use of the BAR filter of the e-Vol DX software application did not induce any dimensional differences on CBCT scans of intracanal posts when compared with measurements made with a micrometer on original posts. The use of the BAR filter eliminated blooming artifacts.

Resumo Este estudo avaliou as dimensões de pinos intrarradiculares usando um novo software de tomografia computadorizada de feixe cônico (TCFC) e um micrômetro digital, e verificou o potencial da redução do artefato de contraste do branco. Sessenta e três dentes humanos unirradiculares foram modelados, obturados, preparados para colocação de pinos e distribuídos em três grupos: G1: pino de fibra de vidro pré-fabricado anatômico; G2: pino metálico de liga de baixa fusão; G3: pino metálico de liga de ouro. Após a confecção e cimentação dos pinos com RelyX U200®, os espécimes foram cortados no sentido axial a 9 mm do ápice radicular, sendo efetuadas marcações em suas superfícies radiculares (eixos X, Y e Z) para orientação das medidas e sincronizações das imagens. Foi utilizado um micrômetro digital para a mensuração das dimensões dos pinos originais (grupo controle) associado ao microscópio operatório. Posteriormente, as imagens em TCFC foram obtidas usando o PreXion 3D Elite®. Para a mensuração dos pinos nas imagens de TCFC utilizou-se o arquivo DICOM e a ferramenta de medida do software e-Vol DX, configurada para medidas milesimais, com o filtro BAR (Blooming Artifact Reduction). Os dados estatísticos foram avaliados com a análise de variância não-paramétrica de Van der Waerden, seguida pelo Teste de Tukey aplicado aos dados normalizados. O nível de significância foi de α = 5%. Os resultados mostraram que as medidas dos diâmetros dos pinos intrarradiculares (fibra de vidro anatômico, metálico liga de baixa fusão, e em liga de ouro) usando o software e-Vol DX e o micrômetro não mostram diferenças significativas entre si. O uso do filtro BAR do software e-Vol DX não induziu diferenças dimensionais nas imagens de TCFC dos pinos quando comparadas às medidas realizadas com o micrômetro sobre os pinos originais. O uso do filtro BAR eliminou artefatos de contraste do branco.

Lateral luxation of incisor - a case report of using a new cone-beam computed tomography software and reposition guideline

Abstract Lateral luxation injuries are one of the most severe periodontal injuries in dental trauma. The correct diagnosis followed by repositioning of the tooth on the right position is fundamental for the periodontal ligament healing. This study reported a clinical case of lateral luxation of maxillary central incisor involving a new cone beam computed tomography (CBCT) software for reconstruction (e-Vol DX) to confirm the lateral luxation after no conclusive dental trauma injury definition by using conventional exam. The lateral luxation injury was digitally reduced by insertion of tooth back to its alveolus, and at the same session, the tooth was stabilized with a rigid splint and further changed to a semi-rigid nylon splint. During the pulpal status monitoring, the pulp was diagnosed necrotic, then the root canal was treated to prevent root resorption. External office-bleaching and restorative procedure was performed. The 4-years follow up and new imaging exam and digital reconstruction confirmed bone healing and no complication. CBCT images analyzed by eVol DX can be used to determine and to guide lateral luxation treatment.

Resumo Lesões de luxação lateral são uma das lesões periodontais mais graves no traumatismo dental. O diagnóstico seguido do reposicionamento do dente na posição correta é fundamental para o reparo do ligamento periodontal. Este estudo relata um caso clínico de luxação lateral do incisivo central superior envolvendo um novo software de reconstrução (e-Vol DX) por tomografia computadorizada de feixe cônico (TCFC) para confirmar a luxação lateral após nenhuma definição de lesão por trauma dental conclusivo pelo exame convencional. A lesão de luxação lateral foi reduzida digitalmente pela inserção do dente de volta ao seu alvéolo e, na mesma sessão, o dente foi estabilizado com uma contenção rígida e posteriormente trocada para uma contenção de nylon semirrígida. Durante o monitoramento da condição pulpar, foi diagnosticada necrose da polpa e, em seguida, o canal radicular foi tratado para evitar a reabsorção radicular. Procedimento externo de clareamento e restauração foi realizado. O acompanhamento de 4 anos e o novo exame de imagem e reconstrução digital não confirmaram reparo ósseo e nenhuma complicação. Imagens de TCFC analisadas pelo e-Vol DX podem ser utilizadas para determinar e orientar lesão de luxação lateral.

CBCT assessment of bone thickness in maxillary and mandibular teeth: an anatomic study

Abstract The site of the sinus tract depends on the rate of resistance against abscess exudate drainage, bone morphology, and distance from the root apex to the outer cortical bone. Objective To assess apical bone thickness in buccal and palatal/lingual aspects of maxillary and mandibular teeth, using a high-resolution cone-beam computed tomography (CBCT) system. Methodology In total, 422 CBCT examinations were included in the study, resulting in a sample of 1400 teeth. The scans were acquired by PreXion 3D, with a high-resolution protocol. The bone thickness was taken as the distance between the center of the apical foramen and the buccal and lingual/palatal cortical bone. The quantitative variables were expressed as mean values±standard deviation. The independent samples were analyzed using the t-test or the Mann-Whitney test (p<0.05). Results The lowest mean value of bone thickness was observed in the buccal cortical bone of the upper canines (1.49 mm±0.86) and in the upper central incisors (1.59 mm±0.67). In premolar teeth, the lowest values were found in the buccal cortical bone of upper first premolars (1.13 mm±0.68). In the posterior teeth, the lowest values were found in the buccal cortical bone of upper first molars (1.98 mm±1.33). In the lower second molar region, the buccal cortical bone (8.36 mm±1.84) was thicker than the lingual cortical bone (2.95 mm±1.16) (p<0.05). Conclusions The lowest mean values of bone thickness are in the buccal cortical bone of the maxillary teeth. In the mandible, bone thickness is thinner in the buccal bone around the anterior and premolar teeth, and in the lingual aspect of mandibular molars. All these anatomic characteristics could make the occurrence of the sinus tract more susceptible in these specific regions of the maxillary and mandibular alveolar bone.

Micro-computed tomographic assessment of the variability and morphological features of root canal system and their ramifications

Abstract Objectives This study assessed the incidence and variability features of root canals system (RCS) and their ramifications according to Pucci & Reig (PR) (1944) and the American Association of Endodontists (AAE) (2017) by micro-computed tomography (μCT). Methodology 500 representative extracted human teeth of each tooth group (n=50) (maxillary/mandibular central and lateral incisors, canines, first and second premolars and molars) were scanned by μCT with a resolution of 26.70 μm. The reconstructed cross-sections images and the visualization of the continuous slices in the transversal axis were performed using DataViewer software. RCS were classified according to Pucci & Reig (main canal, collateral canal, lateral canal, secondary canal, accessory canal, intercanal, recurrent canal) and AAE (main canal, accessory canal, lateral canal). The apical deltas were assessed for both classifications. The prevalence of apical deltas was evaluated using the Chi-squared test (p<0.05). Results According to PR, a higher incidence of lateral canals was observed in maxillary canines (10%), central incisors (8%) and first premolars (6%). Using AAE, the highest incidence of lateral canals was observed in the mandibular first premolars (85%), first and second molars (84%), lateral incisors (67%), canines (59%), and in maxillary first premolars (52%). Regarding accessory canals, the PR showed a frequency in 2% of the maxillary lateral incisors and maxillary and mandibular first premolars and 3% of mandibular first and second molars. On the other hand, the AAE showed the highest incidence of accessory canals in 86% of the maxillary first premolars, 71% in mandibular lateral incisors, 69% in mandibular first premolars, 65% in mandibular canines, and 56% in maxillary canines. The PR showed the lowest incidence of apical deltas for all dental groups when compared with AAE (p=0.004). Interestingly, distal canals in maxillary molars showed a significant discrepancy between classifications (p=0.027). Conclusions μCT enabled accurately describing the RC system and related ramifications, adding to the PR and AAE classifications, with some discrepancies reported for maxillary molars. Clinical Relevance This μCT study enabled a thorough description of the variability among root canals and their ramifications, including clinically relevant details on the presence and location of lateral canals and accessories in all human tooth groups, beyond the currently existing classification systems.

Interference of coronal enamel and dentin thickness and ambient light on pulse oximetry interpretation

Abstract This study evaluated the interference of enamel and coronal dentin thickness and ambient light in pulse oximetry interpretation, using SaO2the human finger as a reference. Forty-two intact human permanent mandibular molars were sectioned mesiodistally in the central portion. Buccal and lingual dentin surfaces were drilled, and 4 mm, 3 mm and 2 mm enamel/dentin thicknesses were interposed between finger and device, after which SaO2 levels were measured by finger pulse oximetry. A reference device was designed to align pulse oximeter light-emitting diode, buccal surface of tooth, little finger, lingual surface of tooth and photodiode. Variables were described as means and standard deviation, and the confidence interval was reported. Repeated measures analysis of variance (ANOVA) was used to compare the groups, followed by Bonferroni correction. Student t test for paired samples was used to determine presence of ambient light (α = 0.05). Mean SaO2 level was lower at 4.0 ± 0.2 mm thickness, regardless of presence or absence of ambient light (92.7% and 89.3%). The other thicknesses yielded values of 95.5% and 94.5% at 3.0 ± 0.2 mm, and 96.4% and 96.0% at 2.0 ± 0.2 mm (p < 0.001). There were significant differences between SaO2 values at 4.0 ± 0.2 mm, 3.0 ± 0.2 mm and 2.0 ± 0.2 mm thicknesses, in the presence of ambient light. Mean SaO2 level in positive control was 96.3%, and mean pulse rate was 69.5 bpm in presence of ambient light; in the absence of light, these values were 96% and 70.5 bpm. Enamel and dentin thickness interfere with SaO2, regardless of presence or absence of ambient light. The lowest SaO2 levels were found for the thickest tooth samples.

Cone-beam and micro-computed tomography for the assessment of root canal morphology: a systematic review

Abstract This study presents an overview of the accuracy of cone beam computed tomography (CBCT) compared with micro-computed tomography (μCT) in the assessment of root canal morphology of extracted human permanent teeth. A database search in PubMed, PubMed Central, Embase, Scopus, Opengrey, Scielo and Virtual Health Library was conducted which compared root canal morphology of extracted human permanent teeth on the accuracy of CBCT with μCT. In accordance with PRISMA statement guidelines, data were extracted on study characteristics, target mediators, sampling and assay techniques and the parameters associated with obtaining the image and ability to identify the root canal morphology. Amongst 2734 records, ten fulfilled the inclusion criteria. Four studies compared the accuracy of CBCT and μCT in the assessment of root canal morphology using Vertucci's classification, with at least one CBCT group or subgroup of each study presented high agreement compared to the μCT. Six studies assessed more detailed root canal morphology, including two articles that found a lack of agreement between these imaging systems. Risk of bias was deemed low in three studies, moderate in four and high in three. CBCT can be as accurate as μCT in the assessment of several morphological features of extracted human permanent teeth; however there are some exceptions related to the more detailed morphological aspects. Voxel size likely influences the ability to detect these features, though the different aspects of exposure setting used in studies components may be confounding factors. CBCT may be considered for the assessment of root canal morphology ex-vivo.