Sealing ability of root-end filling materials.

BACKGROUND: The aim of this research was to compare the apical sealing ability of different root-end filling materials (SuperEBA(®), ProRoot MTA(®), thermoplasticized gutta-percha + AH-Plus(®), thermoplasticized RealSeal(®)), by means of microbial indicators. MATERIALS AND METHODS: Thus, 50 human single-rooted teeth were employed, which were shaped until size 5 0, retro - prepared with ultrasonic tips and assigned to 4 groups, retro-filled with each material or controls. A platform was employed, which was split in two halves: upper chamber-where the microbial suspension containing the biological indicators was introduced (E. faecalis + S. aureus + P. aeruginosa + B. subtilis + C. albicans); and a lower chamber containing the culture medium brain, heart influsion, where 3 mm of the apical region of teeth were kept immersed. Lectures were made daily for 60 days, using the turbidity of the culture medium as indicative of microbial contamination. Statistical analyses were carried out at 5% level of significance. RESULTS: The results showed microbial leakage at least in some specimens in all of the groups. RealSeal(®) has more microbial leakage, statistically significant, compared to ProRoot(®) MTA and SuperEBA(®). No significant differences were observed when compared ProRoot(®) MTA and SuperEBA(®). The gutta-percha + AH Plus results showed no statistically significant differences when compared with the other groups. CONCLUSIONS: All the tested materials showed microbial leakage. Root-end fillings with Super-EBA or MTA had the lowest bacterial filtration and RealSeal shows highest bacterial filtration.

Age Estimation in Brazilian Adults Using the Pulp/Tooth Ratio of the Maxillary Canine and Mandibular Second Premolar.

(1) Background/Objectives: Accurate determination of chronological age is crucial in legal dental identification. This study aimed to compare the effectiveness of different formulas in estimating the age of a Brazilian subpopulation by analyzing the pulp/tooth ratio of the maxillary canine and mandibular second premolar in panoramic and periapical radiographs. (2) Methods: The sample consisted of panoramic and periapical radiographs of 247 individuals. The file of each radiograph was opened in the Adobe Photoshop CS4® program to outline and obtain values in pixels for calculating the pulp/tooth ratio. Statistical analysis was conducted using the SPSS program, with a significance level set at 5%. (3) Results: The interclass correlation coefficient demonstrated excellent intra-observer agreement (0.990-0.999). The determination coefficients (R2) suggested that only 30-35% of the actual age results could be explained by the pulp/tooth ratio. The smallest differences were observed with Cameriere's formula for the mandibular second premolar on panoramic radiographs (+4.1 years). The greatest differences were found with the formulas for the mandibular second premolar in panoramic radiographs of the Korean (+12.5 years) and Portuguese (-12.1 years) populations. (4) Conclusions: The equations employed showed little agreement between the actual age and the estimated age.

Spatial Position and Anatomical Characteristics Associated with Impacted Third Molars Using a Map-Reading Strategy on Cone-Beam Computed Tomography Scans: A Retrospective Analysis.

(1) Background: This study assessed the spatial position and anatomical features associated with impacted third molars through a map-reading strategy employing cone-beam computed tomography (CBCT). (2) Methods: The positioning of impacted third molars on CBCT was assessed using Winter's and Pell and Gregory's classifications. External root resorption in mandibular second molars was categorized according to Herman's classification. Additionally, the relationship between the mandibular third molar root apex and the mandibular canal was examined. Comparative statistical analysis was conducted using Fisher's exact test, with a significance level considered as 5%. (3) Results: The results indicated that, based on Winter's classification, 48.06 % of impacted teeth were positioned mesioangularly. Employing Pell and Gregory's classification, 43.22% of the impacted molars fell into positions B and C, with 54.2% classified as Class II. A notable 69.7% of teeth exhibited no contact between the root apex and the mandibular canal, and external root resorption in the distal aspect of the second molar was absent in 88.7% of cases. (4) Conclusions: Utilizing the map-reading strategy with CBCT scans to assess the anatomical positions and characteristics of impacted third molars enhances professional confidence and sets a standard for quality and safety in the surgical procedure for patients.

Incidental Findings Following Dental Implant Procedures in the Mandible: A New Post-Processing CBCT Software Analysis.

Background/Objectives: The aim of this study was to evaluate incidental findings in the mandible after the placement of dental implants using a new cone-beam computed tomography (CBCT) software. Methods: The initial sample consisted of 2872 CBCT scans of patients of both sexes. The parameters evaluated in this study were the location of the implants in the mandible, implant length, anatomical relationship of the implant with the mandibular canal, presence or absence of damage to the adjacent teeth, presence or absence of implant fractures, and presence or absence of bone support. Fisher's exact test was performed to compare the variables. The significance level was set at p = 0.05. Results: Out of 2872 CBCT scans, 214 images of patients with an average age of 44.5 years were included. The most frequent location of the implants was the posterior region (93.5%), with 54% of the implants having a length between 9 and 14 mm. It was found that 92% of the implants were positioned above the mandibular canal. Damage to adjacent teeth was observed, with no correlation with the implant positioning (p = 1.000). In 100% of cases of implants in the anterior region, there was bone support. Fracture was observed in 1.7% of implants with a length between 9 and 14 mm. Conclusions: The installation of implants in the mandible occurs more frequently in the posterior region, with a high presence of bone support and a low incidence of damage to adjacent teeth, anatomical structures, and fractures.

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

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.

Effect of low-power diode laser on infected root canals.

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.

Method to Identify Accessory Root Canals using a New CBCT Software.

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.

Blooming artifact reduction using different cone-beam computed tomography software to analyze endodontically treated teeth with intracanal posts.

BACKGROUND: The appearance of high-density root obturating materials, such as gutta-percha and intracanal posts, on cone-beam computed tomography (CBCT) scans is substantially different from that seen in the specimen. This study evaluated the effectiveness of different CBCT software in the reduction of blooming artifacts when examining teeth with intracanal posts. METHOD: The sample included 42 human single-rooted teeth with two types of posts: G1 - low-fusion alloy posts; G2 - gold alloy posts. CBCT scans were obtained using two scanners, PreXion 3D Elite® and Carestream 9000C 3D®. First, the posts were measured using a digital micrometer (standard reference, control). Post diameters were determined using the Blooming Artifact Reduction (BAR) tool of the e-Vol DX software and of the PreXion3D Image Analysis System. Statistical data were evaluated using the van Der 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 %. RESULTS: There were no significant differences (p > 0.05) between the diameters of intracanal posts on the CT scans when the e-Vol DX was used, or when these results were compared with those obtained using a micrometer. There were significant differences in post diameters determined using the PreXion3D Image Analysis System when compared with the e-Vol DX and the micrometer values (p < 0.05). CONCLUSIONS: The use of the e-Vol DX BAR filter eliminated blooming artifacts. There were no dimensional changes in the CBCT images of the low-fusion and gold alloy intracanal posts using the e-Vol DX BAR filter.

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

OBJECTIVE: 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. 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.

Sealing ability of three commercial resin-based endodontic sealers.

This study sought to compare the leakage of micro-organisms through root canals that had been obturated using one of three commercial endodontic sealers. Forty maxillary anterior human teeth were randomly assigned to one of three groups, depending on the sealer used. This study utilized an in vitro microbial leakage test with a split chamber design. A mixture of bacterial markers was placed in the upper chamber and could reach the lower chamber (which contained brain heart infusion broth) only by leaking through the root canal filling. Microbial leakage was checked daily for 60 days and data were analyzed statistically by Kruskal-Wallis and Mann-Whitney tests. The materials were further evaluated for antimicrobial effect by an agar diffusion test. The results of the leakage test showed no statistically significant difference between Sealer 26 and AH Plus, although both materials differed significantly from Resilon/Epiphany, which took less time to display microbial leakage. All three sealers demonstrated microbial leakage in less than 60 days; however, the agar diffusion test showed that AH Plus and Resilon/Epiphany induced significantly larger microbial inhibition zones than those induced by Sealer 26.

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.

Dendritic cells and their relation to apical peridontitis.

The purpose of this manuscript was to re-discuss apical periodontitis, apical biofilm, and its possible relationship with dendritic cells (DC). DCs are potent regulators of the immune system and their function is divided into three categories that involve the presentation of antigens: the presentation of antigens and activation of T cells; a not well established category suggested that DCs induce and maintain immunological tolerance; and the maintenance of the immune memory in conjunction with B cells. DCs in periapical inflammatory lesions are composed of at least two subpopulations that can be distinguished on the basis of ultrastructure and phenotype. These populations might differ in lineage, state of maturation, differentiation, activation, and/or function. The authors hereby analyzed the root apexes of teeth under SEM, after performing apicoectomy due to the failure of conventional endodontic treatment. Microbial biofilm with multispecies and areas of resorption with the presence of Howship lacunae, and images suggestive of denditric cells could be observed. The presence of DCs in periapical lesion could be an indication of the severity of the lesion, with a constant presence of antigen in the periradicular region.

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.

Antimicrobial analysis of different root canal filling pastes used in pediatric dentistry by two experimental methods.

The objective of this study was to compare, by two experimental methods, the antimicrobial efficacy of different root canal filling pastes used in pediatric dentistry. The tested materials were: Guedes-Pinto paste (GPP), zinc oxide-eugenol paste (OZEP), calcium hydroxide paste (CHP), chloramphenicol + tetracycline + zinc oxide and eugenol paste (CTZP) and Vitapex. Fiven microbial strains (S. aureus, E. faecalis, P. aeruginosa, B. subtilis and C. albicans) obtained from the American Type Culture Collection were inoculated in Brain Heart Infusion (BHI) and incubated at 37 degrees C for 24 h. For the direct exposure test (DET), 72 paper points were contaminated with the standard microbial suspensions and exposed to the root canal filling pastes for 1, 24, 48 and 72 h. The points were immersed in Letheen Broth (LB), followed by incubation at 37 degrees C for 48 h. An inoculum of 0.1 mL obtained from LB was then transferred to 7 mL of BHI, under identical incubations conditions and the microbial growth was evaluated. The pastes showed activity between 1 and 24 h, depending on the material. For the agar diffusion test (ADT), 30 Petri plates with 20 mL of BHI agar were inoculated with 0.1 mL of the microbial suspension, using sterile swabs that were spread on the medium. Three cavities were made in each agar plate (total = 90) and completely filled with one of the filling root canal pastes. The plates were pre-incubated for 1 h at room temperature and then incubated at 37 degrees C for 24 to 48 h. The inhibition zone around each well was recorded in mm. The complete antimicrobial effect in the direct exposure test was observed after 24 h on all microbial indicators. All root canal filling materials induced the formation of inhibition zones, except for Vitapex (range, 6.0-39.0 mm).

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.

Working Length Determination Using Cone-Beam Computed Tomography, Periapical Radiography and Electronic Apex Locator in Teeth with Apical Periodontitis: A Clinical Study.

INTRODUCTION: The purpose of this clinical study was to compare the accuracy of working length (WL) determination using cone-beam computed tomography (CBCT), conventional periapical radiographies and electronic apex locator. METHODS AND MATERIALS: This study was conducted during root canal treatment of 19 patients with a total of 30 single-rooted teeth diagnosed with apical periodontitis. After taking the initial parallel periapical radiographies, the initial file was advanced into the canal until the WL was detected by the apex locator. Subsequently, the WL was measured and WL radiographies were taken with the file set in the canal. Afterwards, CBCT images were acquired. These three measurements were tabulated and compared and the data were analyzed using the Friedman test. The level of significance was set at 0.05. RESULTS: The mean values for WL determination by electronic apex locator, periapical radiograph and CBCT images were 22.25, 22.43 and 22.65, respectively which was not statistically significant (P>0.05). CONCLUSION: Working length determination using CBCT images was precise when compared to radiographic method and electronic apex locator.

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.

Characterization of successful root canal treatment.

Knowing the outcome of root canal treatment (RCT) is determinant to substantiate the clinical decision making process, especially when RCT is weighed against the extraction of natural teeth or replacement by prosthetic elements. The ideal scenario in all clinical situations should combine healing/prevention of disease (apical periodontitis) and the functional retention of the tooth. Understanding the risk factors associated with endodontic failure is a key factor to increase the chances of success. The logical action is to reverse the existing disease, which requires intervention to neutralize the bacterial invasion and disrupt the bacterial biofilm within the complex anatomy. Success is more predictable when the immune host defenses are favorable. However, success has different meanings to the dentist, to the patient and to the tooth itself. The life of an endodontically treated tooth depends on the accuracy of the diagnosis and planning, excellence of disinfection, instrumentation and filling procedures (antimicrobial strategies, root canal shaping and coronal and apical seal) and finally the rehabilitation management. The interpretation of constant or intermittent pain and/or discomfort associated with apical periodontitis (AP) in endodontically treated tooth may be suggestive of endodontic failure. The success features of RCT, namely absence of pain, regression of AP, tight seal of canal and coronal spaces, and recovery of tooth function, must be reevaluated over time. In case of doubt between success and failure, cone beam computed tomography (CBCT) could be indicated for detection and precise localization of AP. The possibility of map reading on CBCT images characterizes the real multidimensional structure, providing accurate information on the presence, absence or regression of AP. The survival of an endodontically treated tooth implies understanding the biological and mechanical outcomes as multifactorial events over the individual's life span. The objective of this review of literature is to discuss relevant factors associated with patient's health, tooth and dentist that could account for a successful RCT.

Effectiveness of different endodontic irrigants against Enterococcus faecalis: an ex vivo study

Aim: To evaluate the effectiveness of different endodontic irrigants against Enterococcus faecalis (ATCC 29212). Methods: Seventy bovine mandibular incisors were prepared, inoculated with a bacterial strain for 60 days and divided into the following groups: positive control; negative control; 2.5% NaOCl; 17% EDTA; 0.2% chitosan; 2.5% NaOCl + 0.2% chitosan; and 2.5% NaOCl + 17% EDTA. The irrigation protocol was performed using an experimental peristaltic pump device, with the irrigating solutions circulating within the apparatus at a constant flow for 10 min. Paper-point samples were then collected from the root canals and immersed in 7 mL of brain heart infusion broth, followed by incubation at 37°C for 48 h. Bacterial growth was assessed by turbidity of the culture medium. Results: E. faecalis was present in all samples after the use of different irrigants. Conclusion: The different irrigants tested were not effective in completely eliminating dentin bacterial contamination with E. faecalis.

Detection of root canal isthmuses in molars by map-reading dynamic using CBCT images.

The aim of this study was to detect root isthmuses in maxillary and mandibular molars and evaluate their frequencies using map-reading dynamics in CBCT images. Two hundred extracted human maxillary and mandibular molars were used in ex vivo assay. A consecutive sample of two hundred maxillary and mandibular molars (first and second) was selected from CBCT exams. The isthmuses were detected from the pulp orifice to the apex and were recorded according to their beginning and their end, into categories: 1. begin and end in cervical third; 2. beginning in cervical third and end in middle third; 3. beginning in cervical third and end in apical third; 4. beginning and end in middle third; 5. begin in middle third and end in apical third; 6. beginning and end in apical third; 7. no isthmus. The scans were obtained in different planes with map-reading in axial slices of 0.5 mm/0.5 mm involved the coronal to apical direction. The frequencies of isthmus were analyzed according to the level of root and evaluated by Chi-square test. The level of significance was set at α=0.05. The presence of isthmus detected in maxillary molars was 86% in ex vivo assay and 62% in vivo assay, whereas in mandibular molars was observed 70% in ex vivo assay and 72% in vivo assay. The frequency of isthmus was high in both study models. The map-reading dynamics in CBCT images was found to be precise to detect the localization of isthmus.