Natural canal deviation and dentin thickness of mesial root canals of mandibular first molars assessed by microcomputed tomography.

The aim of this study was to assess the centralization and dentin thickness of mesial root canals of the first mandibular molars by microcomputed tomography (micro-CT). Material and methods: Ninety-nine mandibular molars of Vertucci's type IV canals were scanned by micro-CT. The mesiodistal deviation and centroid were assessed, in both mesiobuccal (MB) and mesiolingual (ML) canals, for the apical 4mm and the full canal length. Results: The dentin thickness was similar for both MB and ML canals. The narrowest thickness was in the distal wall of an MB canal (0.07mm), while the widest was found in the mesial wall of an MB canal (2.46mm). In centroid analysis, both the MB and ML canals exhibited deviations when compared to the root centroid, along the full canal length and the apical 4mm. For the MB canal, the mean deviation was 0.83mm (0.02 mm-2.30 mm) for the full canal and 0.18mm (0.01 mm-1.01 mm) for apical 4mm. Similarly, for the ML canal, the mean deviation measured 0.83 mm (0.05mm-3.99mm) for the full canal and 0.21 mm (0.01mm-1.01mm) for the apical 4 mm. Overall, deviations were observed towards the mesial of the roots, with 69% for MB and 57% for ML canals for the full canal, and 51% for MB canals within the 4 mm. The exception was the ML canal, which exhibited a higher deviation towards distal in the apical 4mm, accounting for 52% of cases. The dentin thickness was consistent between the mesial canals of mandibular molars. However, there is no centrality of mesial canals in their roots, with frequent deviation to mesial.

Correlation Between Proinflammatory Cytokine Expression and Clinical Data in Apical Granuloma.

INTRODUCTION: This study was intended to evaluate the expression of inflammatory cytokines commonly secreted by CD4+ T cells (IL-2, IL-5, IL-17, TGF-ß, TNF-α, and IFN-γ) in apical granulomas and correlate with the clinical conditions and time elapsed since root canal treatment. METHODS: Eighteen biopsy specimens obtained by periradicular surgery of teeth with post-treatment apical periodontitis and diagnosed as apical granuloma were available from the oral pathology laboratory. Silanized slides containing paraffin sections were used for immunohistochemical reactions. Images were analyzed by using an optical microscopy and each slide was subdivided into 5 fields at high magnification. RESULTS: IFN-γ and TGF-ß were the cytokines with the highest expression levels. There were statistically significant differences when comparing IL-2 and IFN-γ (P < .05), and IL-2 and TGF-ß (P < .05). Comparison between the detected cytokines and clinical data and time of treatment demonstrated significant correlation (P < .05) between lower expression of IL-2 and the presence of painful symptoms, absence of sinus tract, and treatments performed more than 4 years before. It was also possible to observe a significant correlation between lower expression of IL-5 and treatments performed less than 4 years before (P < .05). CONCLUSION: IFN-γ and TGF-ß were highly expressed in apical granulomas. However, only IL-2 and IL-5 levels were associated with clinical data and time since previous root canal treatment.

Bacteriologic Conditions of the Apical Root Canal System of Teeth with and without Posttreatment Apical Periodontitis: A Correlative Multianalytical Approach.

INTRODUCTION: This study used a correlative multianalytical approach to investigate the bacteriologic conditions in the apical root canal system of treated teeth with or without apical periodontitis and their correlation with the technical quality of the previous root canal obturation and the presence and volume of apical periodontitis lesions. METHODS: Root apexes were obtained from recently extracted root canal-treated teeth with (n = 23) and without (n = 22) apical periodontitis lesions as demonstrated by cone-beam computed tomographic examination. The root apexes were sectioned and subjected to micro-computed tomographic (micro-CT) scanning. The specimens were cryopulverized, and DNA extracted from the powder was used as a template in real-time polymerase chain reaction assays to quantify total bacteria and members of the Streptococcus genus and Actinobacteria phylum. The bacteriologic findings were compared between the 2 groups and also evaluated for associations with cone-beam computed tomographic and micro-computed tomographic data. RESULTS: Bacteria were detected in all apical canal samples except 1. The mean counts of total bacteria, streptococci, and actinobacteria did not differ significantly between teeth with or without apical periodontitis (P > .05). Streptococcus levels were significantly lower by 80% in the apical canals of teeth with small lesions compared with those without lesions (P < .05). The limit of filling >2 mm short was significantly associated with more total bacterial counts compared with canals filled 0-2 mm short (P < .05). An adequate coronal restoration was significantly associated with lesser counts of Streptococcus (P < .05). CONCLUSIONS: Comparable bacterial loads were observed in the apical canal system of treated teeth with and without apical periodontitis, suggesting that factors other than only the total bacterial levels may also influence the development and progression of apical periodontitis. Bacteria were found in the apical canal in virtually all cases with a high prevalence of streptococci and actinobacteria. Streptococci counts were significantly higher in the apical canal of teeth with inadequate restorations and teeth with no lesions. Underfilled canals showed higher bacterial counts.

Natural canal deviation and dentin thickness of mesial root canals of mandibular first molars assessed by microcomputed tomography

Abstract The aim of this study was to assess the centralization and dentin thickness of mesial root canals of the first mandibular molars by microcomputed tomography (micro-CT). Material and methods: Ninety-nine mandibular molars of Vertucci's type IV canals were scanned by micro-CT. The mesiodistal deviation and centroid were assessed, in both mesiobuccal (MB) and mesiolingual (ML) canals, for the apical 4mm and the full canal length. Results: The dentin thickness was similar for both MB and ML canals. The narrowest thickness was in the distal wall of an MB canal (0.07mm), while the widest was found in the mesial wall of an MB canal (2.46mm). In centroid analysis, both the MB and ML canals exhibited deviations when compared to the root centroid, along the full canal length and the apical 4mm. For the MB canal, the mean deviation was 0.83mm (0.02 mm-2.30 mm) for the full canal and 0.18mm (0.01 mm-1.01 mm) for apical 4mm. Similarly, for the ML canal, the mean deviation measured 0.83 mm (0.05mm-3.99mm) for the full canal and 0.21 mm (0.01mm-1.01mm) for the apical 4 mm. Overall, deviations were observed towards the mesial of the roots, with 69% for MB and 57% for ML canals for the full canal, and 51% for MB canals within the 4 mm. The exception was the ML canal, which exhibited a higher deviation towards distal in the apical 4mm, accounting for 52% of cases. The dentin thickness was consistent between the mesial canals of mandibular molars. However, there is no centrality of mesial canals in their roots, with frequent deviation to mesial.

Resumo O objetivo deste trabalho foi avaliar a centralização e a espessura da dentina dos canais radiculares mesiais de primeiros molares inferiores por meio de microtomografia computadorizada (micro-CT). Material e métodos: Noventa e nove molares inferiores com canais tipo IV de Vertucci foram escaneados por micro-TC. O desvio mesiodistal e o centroide foram avaliados para os canais mesiovestibular (MB) e mesiolingual (ML), nos 4mm apicais e em todo o comprimento do canal. Resultados: A espessura da dentina foi semelhante para os canais MB e ML. A espessura mais estreita foi encontrada na parede distal de um canal MB (0,07mm), enquanto a mais larga foi encontrada na parede mesial de um canal MB (2,46mm). Na análise centroide, tanto o canal MB quanto o ML exibiram desvios quando comparados ao centroide da raiz, ao longo de todo o comprimento do canal e nos 4 mm apicais. Para o canal MB, o desvio médio foi de 0,83mm (0,02mm-2,30mm) para canal inteiro e 0,18mm (0,01mm-1,01mm) para o apical de 4mm. Da mesma forma, para o canal ML, o desvio médio mediu 0,83 mm (0,05 mm-3,99 mm) para o canal inteiro e 0,21 mm (0,01 mm-1,01 mm) para os 4 mm apicais. No geral, foram observados desvios em direção mesial das raízes, sendo 69% para canais MB e 57% para canais ML para canal inteiro, e 51% para canais MB dentro dos 4 mm. A exceção foi o canal ML, que apresentou maior desvio para distal nos 4mm apicais, representando 52% dos casos. A espessura da dentina foi consistente entre os canais mesiais dos molares inferiores. Entretanto, não há centralidade dos canais mesiais em suas raízes, com frequente desvio para mesial.

Morphological assessment of the isthmus in mesial root canals of first mandibular molars / Avaliação morfológica do istmo nos canais radiculares mesiais dos primeiros molares inferiores

ABSTRACT Root canal morphology and its anatomical variations pose a great challenge to endodontists Aim The aim of this in silico study was to perform a qualitative and quantitative analysis of the threedimensional morphological characteristics of the isthmus in the mesial root canals of mandibular molars using microcomputed tomography (micro-CT) Material and Method Six hundred first mandibular molars were selected, including 317 with two mesial canals with isthmuses between the canals, and fully formed root. Isthmus morphology was determined in 3D longitudinal sections using Fan et al. (2010) classification. Root length, and the volume and area of apical and coronal level were measured. Additionally, the structural model index (SMI) of the canals were also assessed Results The prevalence of isthmuses in the mesial root canals was 32% type II, 29% type III, 22% type IV, and 17% type I. The root length was found to be 9.1±0.5 mm, the volume and area, of all root canal system, were 41.8±40.1 mm3 and 63.6±24.2 mm2 respectively. The isthmi volume and area alone were 11.06±9.03 mm3 and 30.02±11.02 mm2. The study confirmed that isthmuses are present in mesial canals of mandibular first molars, being more frequent in the apical third Conclusion The high prevalence of isthmuses with complex morphological features underscores the importance of using intracanal medications to disinfect areas unprepared by instruments.

RESUMO A morfologia do canal radicular e suas variações anatômicas representam um grande desafio para os endodontistas. O objetivo deste estudo ex vivo foi realizar uma análise qualitativa e quantitativa das características morfológicas tridimensionais do istmo nos canais mesiais de molares inferiores por meio de microtomografia computadorizada (micro-CT) Material e Método Foram selecionados 600 primeiros molares inferiores, incluindo 317 com dois canais mesiais com istmos e raiz totalmente formada. A morfologia do istmo foi determinada em cortes longitudinais 3D usando a classificação Fan et al. (2010). Foram mensurados o comprimento da raiz, o volume e a área apical e coronal e da cavidade pulpar. Adicionalmente, também foram avaliados o structure model index (SMI) dos canais Resultados A prevalência de istmos nos canais mesiais foi de 32% tipo II, 29% tipo III, 22% tipo IV e 17% tipo I. O comprimento da raiz foi de 9,1±0,5 mm, o volume e a área de todo o sistema de canais radiculares foram de 41.8±40.1 mm3 e 63.6±24.2 mm2, respectivamente. O volume e área do istmo isoladamente foram 11.06±9,03 mm3 e 30.02±11.02 mm2. O estudo confirmou que os istmos estão presentes em canais mesiais dos primeiros molares inferiores, sendo mais frequentes no terço apical Conclusão A alta prevalência de istmos com características morfológicas complexas ressalta a importância do uso de medicação intracanal para desinfecção de áreas não tocadas por instrumentos.

Multipopulation evaluation of the internal morphology of mandibular first premolars from different South American countries. A micro-computed tomography study.

OBJECTIVE: To evaluate and compare several anatomical parameters of mandibular first premolars from individuals from different Latin American countries using micro-computed tomography. DESIGN: Five hundred extracted mandibular first premolars from Brazilian, Argentinian, Chilean, Colombian, and Ecuadorian individuals were scanned using micro-computed tomography (n = 100 teeth/country). Root canal configurations were classified according to established parameters. Analyses also included: canal volume and surface area, structure model index, distances from the apical foramen to the root apex or the cementoenamel junction, major/minor apical canal diameters, canal orifice shape, and prevalence of ramifications. RESULTS: A single root was the most common anatomy in all countries (range, 97%-100%). Vertucci's type-I canal was the most frequent configuration (range, 36%-66%), followed by C-shaped and type-V canals. The oval-shaped canal orifice was the most predominant in all countries (range, 34%-58%), followed by the circular shape (range, 16%-47%). C-shaped canals occurred in all subpopulations (range, 14%-26%), always associated with radicular grooves. Ranges for canal ramifications were as follows: accessory canals, 36%-73%; lateral canals, 4%-12%; and apical delta, 4%-14% of the teeth. Many anatomic parameters differed significantly between countries (P < .05). CONCLUSIONS: Vertucci's types-I and -V, and C-shaped canals were the most prevalent configurations in the subpopulations investigated. Accessory canals and several complex anatomies were found, with some significantly different frequencies between countries.

Effects of Calcium Hydroxide Paste in Different Vehicles on Bacterial Reduction during Treatment of Teeth with Apical Periodontitis.

INTRODUCTION: This clinical study evaluated the antibacterial effects of calcium hydroxide associated with different vehicles during the treatment of infected teeth with apical periodontitis. METHODS: Bacteriologic samples were taken from 90 necrotic root canals of teeth with apical periodontitis before (S1) and after preparation with a rotary nickel-titanium instrument system and 2.5% sodium hypochlorite irrigation (S2). The teeth were distributed in 3 groups according to the intracanal medication used, which consisted of a calcium hydroxide paste in glycerin, camphorated paramonochlorophenol/glycerin (CHPG), or 2% chlorhexidine for 1 week, and then another sample was taken (S3). The frequency of bacteria-positive cases and the reduction of bacterial counts were evaluated by quantitative real-time polymerase chain reaction. RESULTS: Substantial intracanal bacterial reduction was observed after preparation in the 3 groups (P < .001). After calcium hydroxide paste in glycerin medication, the number of bacteria-positive cases decreased from 20/29 (69%) to 17/29 (59%); however, the mean bacterial counts increased 8.4% from S2 to S3. Medication with CHPG reduced the number of bacteria-positive cases from 17/29 (59%) to 15/29 (52%), with a significant mean S2-S3 reduction of 71% (P < .05). In the chlorhexidine group, the number of bacteria-positive cases decreased from 21/30 (70%) to 17/30 (57%) after medication, with a mean S2-S3 reduction of 55%, which, however, was not statistically significant (P > .05). Intergroup comparisons showed no significant differences (P > .05). CONCLUSION: Comparison between the 3 calcium hydroxide pastes showed no significant differences in antibacterial effectiveness in the main root canal. However, only the CHPG paste showed a significant reduction in bacterial counts when postpreparation and postmedication samples were compared.

Morphological assessment of the isthmus in mesial root canals of first mandibular molars.

Root canal morphology and its anatomical variations pose a great challenge to endodontists. Aim: The aim of this in silico study was to perform a qualitative and quantitative analysis of the threedimensional morphological characteristics of the isthmus in the mesial root canals of mandibular molars using microcomputed tomography (micro-CT). Material and Method: Six hundred first mandibular molars were selected, including 317 with two mesial canals with isthmuses between the canals, and fully formed root. Isthmus morphology was determined in 3D longitudinal sections using Fan et al. (2010) classification. Root length, and the volume and area of apical and coronal level were measured. Additionally, the structural model index (SMI) of the canals were also assessed. Results: The prevalence of isthmuses in the mesial root canals was 32% type II, 29% type III, 22% type IV, and 17% type I. The root length was found to be 9.1±0.5 mm, the volume and area, of all root canal system, were 41.8±40.1 mm3 and 63.6±24.2 mm2 respectively. The isthmi volume and area alone were 11.06±9.03 mm3 and 30.02±11.02 mm2. The study confirmed that isthmuses are present in mesial canals of mandibular first molars, being more frequent in the apical third. Conclusion: The high prevalence of isthmuses with complex morphological features underscores the importance of using intracanal medications to disinfect areas unprepared by instruments.

A morfologia do canal radicular e suas variações anatômicas representam um grande desafio para os endodontistas. O objetivo deste estudo ex vivo foi realizar uma análise qualitativa e quantitativa das características morfológicas tridimensionais do istmo nos canais mesiais de molares inferiores por meio de microtomografia computadorizada (micro-CT). Material e Método: Foram selecionados 600 primeiros molares inferiores, incluindo 317 com dois canais mesiais com istmos e raiz totalmente formada. A morfologia do istmo foi determinada em cortes longitudinais 3D usando a classificação Fan et al. (2010). Foram mensurados o comprimento da raiz, o volume e a área apical e coronal e da cavidade pulpar. Adicionalmente, também foram avaliados o structure model index (SMI) dos canais. Resultados: A prevalência de istmos nos canais mesiais foi de 32% tipo II, 29% tipo III, 22% tipo IV e 17% tipo I. O comprimento da raiz foi de 9,1±0,5 mm, o volume e a área de todo o sistema de canais radiculares foram de 41.8±40.1 mm3 e 63.6±24.2 mm2, respectivamente. O volume e área do istmo isoladamente foram 11.06±9,03 mm3 e 30.02±11.02 mm2. O estudo confirmou que os istmos estão presentes em canais mesiais dos primeiros molares inferiores, sendo mais frequentes no terço apical. Conclusão: A alta prevalência de istmos com características morfológicas complexas ressalta a importância do uso de medicação intracanal para desinfecção de áreas não tocadas por instrumentos.

Antibiotic indication in endodontics by Colombian dentists with different levels of training: a survey / Indicação dos antibióticos em Endodontia por dentistas colombianos com diferentes níveis de formação: uma pesquisa por questionário

ABSTRACT Aim: This study investigated how Colombian dentists with different academic levels indicate antibiotics with therapeutic purposes in endodontics. Materials and method: A cross-sectional survey was conducted among 559 dentists in the form of an online questionnaire. Results: Three hundred and twenty questionnaires were answered (57.2%). There were significant differences among respondents. For irreversible pulpitis, 140 dentists (43.7%) said they prescribe antibiotics (57.5% of general practitioners, 20.1% of specialists and 38.9% of those with Master's and/or PhD degrees), while for symptomatic apical periodontitis, 183 (57.2%) did so (74.1% of general practitioners, 28.4% of specialists and 50.0% of those with Master's and/or PhD degrees) (p < 0.05). Amoxicillin was the most frequently prescribed antibiotic, and its association with clavulanic acid was the most often cited for acute periradicular abscess with systemic involvement. Conclusions: The greatest misunderstandings in prescribing antibiotics occurred among general practitioners. Considering all clinical conditions that do not require antibiotics, 60% of general practitioners and 34% of specialists, on average, indicated antibiotics.

RESUMO Objetivo: Este estudo investigou como dentistas colombianos com diferentes níveis acadêmicos indicaram antibióticos com fins terapêuticos em Endodontia. Materiais e método: Realizou-se um levantamento transversal com 559 dentistas. Foi enviado um questionário online. Resultados: Foram respondidos 320 questionários (57,2%). Houve diferenças significativas entre os profissionais com diferentes níveis de formação. Para pulpite irreversível, 140 (43,7%) dentistas afirmaram indicar antibióticos (57,5% clínicos gerais, 20,1% especialistas e 38,9% com mestrado e/ou doutorado), enquanto para periodontite apical sintomática, 183 (57,2%) prescrevem estes medicamentos (74,1% clínicos, 28,4% especialistas e 50,0% com mestrado e doutorado) (p < 0,05). A amoxicilina foi a mais indicada entre os profissionais, e sua associação com ácido clavulânico foi a mais referida para abscesso perirradicular agudo com acometimento sistêmico. Conclusões: Os maiores equívocos na prescrição de antibióticos ocorreram com os clínicos gerais. Considerando todas as condições clínicas que não requerem antibióticos, 60% dos clínicos gerais e 34% dos especialistas, em média, indicaram estes medicamentos.

Antibiotic indication in endodontics by Colombian dentists with different levels of training: a survey.

AIM: This study investigated how Colombian dentists with different academic levels indicate antibiotics with therapeutic purposes in endodontics. MATERIALS AND METHOD: A cross-sectional survey was conducted among 559 dentists in the form of an online questionnaire. RESULTS: Three hundred and twenty questionnaires were answered (57.2%). There were significant differences among respondents. For irreversible pulpitis, 140 dentists (43.7%) said they prescribe antibiotics (57.5% of general practitioners, 20.1% of specialists and 38.9% of those with Master's and/or PhD degrees), while for symptomatic apical periodontitis, 183 (57.2%) did so (74.1% of general practitioners, 28.4% of specialists and 50.0% of those with Master's and/or PhD degrees) (p<0.05). Amoxicillin was the most frequently prescribed antibiotic, and its association with clavulanic acid was the most often cited for acute periradicular abscess with systemic involvement. CONCLUSIONS: The greatest misunderstandings in prescribing antibiotics occurred among general practitioners. Considering all clinical conditions that do not require antibiotics, 60% of general practitioners and 34% of specialists, on average, indicated antibiotics.

OBJETIVO: Este estudo investigou como dentistas colombianos com diferentes níveis acadêmicos indicaram antibióticos com fins terapêuticos em Endodontia. Materiais e método: Realizou-se um levantamento transversal com 559 dentistas. Foi enviado um questionário online. RESULTADOS: Foram respondidos 320 questionários (57,2%). Houve diferenças significativas entre os profissionais com diferentes níveis de formação. Para pulpite irreversível, 140 (43,7%) dentistas afirmaram indicar antibióticos (57,5% clínicos gerais, 20,1% especialistas e 38,9% com mestrado e/ou doutorado), enquanto para periodontite apical sintomática, 183 (57,2%) prescrevem estes medicamentos (74,1% clínicos, 28,4% especialistas e 50,0% com mestrado e doutorado) (p < 0,05). A amoxicilina foi a mais indicada entre os profissionais, e sua associação com ácido clavulânico foi a mais referida para abscesso perirradicular agudo com acometimento sistêmico. Conclusões: Os maiores equívocos na prescrição de antibióticos ocorreram com os clínicos gerais. Considerando todas as condições clínicas que não requerem antibióticos, 60% dos clínicos gerais e 34% dos especialistas, em média, indicaram estes medicamentos.

Micro-computed tomographic evaluation of root canal morphology in mandibular first premolars from a Colombian population.

Dental anatomy can vary significantly between different populations from different countries. Dental anatomical variations are of great interest to the dental professional, especially to endodontists, since they can influence the outcome of endodontic treatment. The purpose of the present study was to describe the anatomical variations of the root canal in mandibular first premolars in a population from Colombia, using micro-computed tomography. Fifty mandibular first premolars were scanned on a SkyScan 1174 and the microcomputed tomographic images were reconstructed. Anatomy was assessed using three-dimensional models. The parameters used were: Vertucci's classification, area and volume, perimeter, circularity, and major and minor diameter at 1, 2 and 3 mm from the apical foramen. According to the Vertucci's classification, teeth were classified as: types I (40%), V (24%), VII (4%) and III (4%), with 28% not classifiable. C-shaped canals were found in 1.8% of the sample. Mean evaluations at 1, 2, 3 mm of the foramen were as follows, respectively: perimeter 1.07 ± 0.57, 1.27 ± 0.78 and 1.57 ± 0.84 mm; circularity 0.59 ± 0.19, 0.57 ± 0.20 and 0.56 ± 0.22; maximum diameter 0.41 ± 0.23, 0.48 ± 0.33 and 0.60 ± 0.37 mm; minimum diameter 0.24 ± 0.10, 0.26 0.11 and 0.21 ± 0.13 mm. Mean total area and volume were 61.27 ± 16.47 mm2 and 12.47 ± 4.95 mm3, respectively. There was wide anatomical variation in mandibular first premolars from Colombian individuals, reinforcing the need for proper anatomical knowledge to establish more effective strategies for endodontic treatment.

A anatomia dentária pode variar significativamente entre diferentes populações, de diferentes países. As variações anatômicas dentais são de grande interesse para o profissional da odontologia, principalmente para os endodontistas, pois podem influenciar no resultado do tratamento endodôntico. Descrever as variações anatômicas do canal radicular dos primeiros prémolares inferiores em uma população da Colômbia, usando a micro tomografia computadorizada. Cinquenta primeiros prémolares inferiores foram digitalizados em um SkyScan 1174 e as imagens tomográficas foram reconstruídas e a anatomia foi avaliada por meio de modelos tridimensionais. Os parâmetros utilizados foram: classificação de Vertucci, área e volume, perímetro, circularidade e diâmetros maior e menor a 1, 2 e 3 mm do forame apical. De acordo com a classificação de Vertucci, os dentes foram classificados em: tipos I (40%), V (24%), VII (4%) e III (4%), sendo 28% não classificáveis. Canais em forma de C foram encontrados em 1,8% da amostra. As avaliações médias em 1, 2, 3 mm do forame foram as seguintes, respectivamente: perímetro 1,07 ± 0,57, 1,27 ± 0,78 e 1,57 ± 0,84 mm; circularidade 0,59 ± 0,19, 0,57 ± 0,20 e 0,56 ± 0,22; diâmetro maior 0,41 ± 0,23, 0,48 ± 0,33 e 0,60 ± 0,37 mm; diâmetro menor 0,24 ± 0,10, 0,26 ± 0,11 e 0,21 ± 0,13 mm. A média da área total e do volume foram 61,27 ± 16,47 mm2 e 12,47 ± 4,95 mm3, respectivamente. Houve uma grande variação anatômica nos primeiros pré-molares inferiores de colombianos, reforçando a necessidade de conhecimento anatômico adequado para estabelecer estratégias mais eficazes para o tratamento endodôntico.

Accuracy of Microcomputed Tomography in Detecting Dentinal Cracks: A Correlative Study with Scanning Electron and Operative Microscopy.

The aim of the study was to evaluate the accuracy of microcomputed tomography (mCT) to detect dentinal cracks when compared with scanning electron microscopy (SEM) and operating microscopy (OM). Different conditions of pixel size (10 or 17 µm), sample moisture (dry/moist), and transillumination (with/without) were evaluated. Additionally, the influence of the dentinal defect width on its detection was analyzed. The root canals of human mandibular incisors were prepared with the Reciproc R40 instrument (VDW, Munich, Germany). The roots were sectioned 5 and 10 mm from the apex, and mCT scans of middle and apical segments were performed at two pixel sizes: 10 µm and 17 µm, under dry and moist conditions (groups: 10dry, 10moist, 17dry, and 17moist). The operating microscope was used with and without transillumination (groups: OMTrans and OM). Findings showed that accuracy was moderate for the 10dry, 10moist, and OMTrans groups, poor for OM and very poor for 17dry and 17moist. The thickness of the dentin crack significantly influenced its detection by mCT using the resolution of 10 µm in both dry and wet conditions (P = .002), 17 µm in the dry condition (P = .002), and by the operating microscope using transillumination (P = .009). Some cracks visualized in SEM were not detected by mCT and an operating microscope. Not only the mCT resolution but also the sample moisture condition and the dentinal crack width can significantly influence its detection.

Micro-computed tomographic evaluation of root canal morphology in mandibular first premolars from a Colombian population / Avaliaçao microromográfica da morfologia interna de canais de primeiros pré-molares de uma populaçao colombiana

ABSTRACT Dental anatomy can vary significantly between different populations from different countries. Dental anatomical variations are of great interest to the dental professional, especially to endodontists, since they can influence the outcome of endodontic treatment. The purpose of the present study was to describe the anatomical variations of the root canal in mandibular first premolars in a populationfrom Colombia, using micro-computed tomography. Fifty mandibular first premolars were scanned on a SkyScan 1174 and the microcomputed tomographic images were reconstructed. Anatomy was assessed using three-dimensional models. The parameters used were: Vertucci's classification, area and volume, perimeter, circularity, and major and minor diameter at 1, 2 and 3 mm from the apical foramen. According to the Vertucci's classification, teeth were classified as: types I (40%), V (24%), VII (4%) and III (4%), with 28% not classifiable. C-shaped canals were found in 1.8% of the sample. Mean evaluations at 1, 2, 3 mm of the foramen were as follows, respectively: perimeter 1.07 ± 0.57, 1.27 ± 0.78 and 1.57 ± 0.84 mm; circularity 0.59 ± 0.19, 0.57 ± 0.20 and 0.56 ± 0.22; maximum diameter 0.41 ± 0.23, 0.48 ± 0.33 and 0.60 ± 0.37 mm; minimum diameter 0.24 ± 0.10, 0.26 ± 0.11 and 0.21 ± 0.13 mm. Mean total area and volume were 61.27 ± 16.47 mm2 and 12.47 ± 4.95 mm3, respectively. There was wide anatomical variation in mandibular first premolars from Colombian individuals, reinforcing the need for proper anatomical knowledge to establish more effective strategies for endodontic treatment.

RESUMO A anatomia dentària pode variar significativamente entre diferentes populagoes, de diferentes países. As variagoes anatómicas dentais sao de grande interesse para o profissionai da odontologia, principalmente para os endodontistas, pois podem influenciar no resultado do tratamento endodóntico. Descrever as variagoes anatómicas do canal radicular dos primeiros pré-molares inferiores em uma populagao da Colómbia, usando a micro tomografia computadorizada. Cinquenta primeiros pré-molares inferiores foram digitalizados em um SkyScan 1174 e as imagens tomográficas foram reconstruidas e a anatomia foi avaliada por meio de modelos tridimensionais. Os parámetros utilizados foram: classificagao de Vertucci, área e volume, perímetro, circularidade e diámetros maior e menor a 1, 2 e 3 mm do forame apical. De acordo com a classificagao de Vertucci, os dentes foram classificados em: tipos I (40%), V (24%), VII (4%) e III (4%), sendo 28% nao classificáveis. Canais em forma de C foram encontrados em 1,8% da amostra. As avaliaçoes médias em 1, 2, 3 mm do forame foram as seguintes, respectivamente: perímetro 1,07 ± 0,57, 1,27 ± 0,78 e 1,57 ± 0,84 mm; circularidade 0,59 ± 0,19, 0,57 ± 0,20 e 0,56 ± 0,22; diámetro maior 0,41 ± 0,23, 0,48 ± 0,33 e 0,60 ± 0,37 mm; diámetro menor 0,24 ± 0,10, 0,26 ± 0,11 e 0,21 ± 0,13 mm. A média da área total e do volume foram 61,27 ± 16,47 mm2 e 12,47 ± 4,95 mm3, respectivamente. Houve uma grande variaçâo anatómica nos primeiros pré-molares inferiores de colombianos, reforçando a necessidade de conhecimento anatómico adequado para estabelecer estratégias mais eficazes para o tratamento endodóntico.

Quality of Root Canal Filling Using a Bioceramic Sealer in Oval Canals: A Three-Dimensional Analysis.

OBJECTIVES: The oval canals may be associated with inadequate debridement, which can affect the quality of the root canal filling, thus the treatment outcome. The aim of the present work was to compare the quality of oval canals fillings using EndoSequence BC sealer with the single-cone technique or cold lateral compaction. MATERIALS AND METHODS: Thirty-eight human single-rooted premolars with oval canals were instrumented to 1 mm from the apical foramen with hand nickel-titanium files, followed by circumferential filing with Hedstrom files. Teeth were paired into two groups based on their micro-computed tomography (CT) morphological parameters. Both groups were filled using EndoSequence BC sealer. The first used a single cone and the other with the cold lateral compaction technique. The voids volume was evaluated by micro-CT and the percentage was calculated for the total length and for the apical 5 mm of each canal. The Mann-Whitney U test was used to assess whether the surface area and obturation length differed significantly between the groups and to compare the percentage of voids for each technique. RESULTS: Both techniques resulted in less than 16% voids, with no statistically significant difference between them for the total canal length and for the apical 5 mm (p > 0.05). CONCLUSIONS: The quality of the obturation performed with the single-cone technique was similar to that achieved with lateral compaction using EndoSequence BC sealer in oval canals.

Supplementing filling material removal with XP-Endo Finisher R or R1-Clearsonic ultrasonic insert during retreatment of oval canals from contralateral teeth.

This study compared the efficacy of XP-Endo Finisher R and R1-Clearsonic insert in removing filling material remnants from oval canals. Twelve pairs of contralateral premolars were treated and subsequently retreated with Reciproc 50. A supplementary procedure with XP-Endo Finisher R or R1-Clearsonic was performed. Micro-computed tomography was used to quantify the filling material volume in the full canal and apical segment lengths. Intragroup analyses revealed significant reduction of filling material after both procedures, not only in the full canal but also in the apical segment (P < 0.05). The amount of filling material removed with XP-Endo Finisher R and R1-Clearsonic was 47.9% and 52.2% in the apical segment (P > 0.05), and 82.1% and 64.6% in the full canal (P < 0.05). None of the instruments was effective in completely removing the filling material from the apical canal, but better results were obtained with XP-Endo Finisher R in the total canal length.

Disinfection and outcome of root canal treatment using single-file or multifile systems and Ca(OH)2 medication.

This clinical study reports on the antibacterial effects and outcome of endodontic treatment using either a single-file or a multifile system, associated with calcium hydroxide interappointment medication. The root canals of single-rooted teeth with apical periodontitis were treated by using either Reciproc or BioRaCe instrument systems, 2.5% NaOCl irrigation, and calcium hydroxide medication. Bacteriological samples taken before preparation and immediately before obturation were evaluated for total bacterial counts by quantitative real-time polymerase chain reaction (qPCR). Patients were followed up and the treatment outcome was assessed by clinical and radiographic criteria. Decreasing lesions were classified as success in a lenient criterion or failure in a rigid one. Bacteria were detected in all initial samples (47 cases) and were significantly reduced after treatment in both groups (p<0.001). In the Reciproc and BioRaCe groups, 7/25 (28%) and 11/22 (50%) root canals yielded negative qPCR results before obturation, respectively (p>0.05). Quantitative bacterial reduction was similar between groups (p>0.05). The success rate in the BioRaCe group was 95.5% and 77% in the loose and rigid criterion, respectively. In the Reciproc group, corresponding figures were 88% and 76%. Differences in outcome were not significant (p>0.05). No diseased case showed negative qPCR results for bacteria. A difference of >1 Log10 counts was observed between healed and diseased cases. Root canal treatments of teeth with apical periodontitis using a single-file or a multifile system for preparation, associated with NaOCl irrigation and calcium hydroxide interappointment medication, showed similar antibacterial effectiveness and success rate.

Disinfection and outcome of root canal treatment using single-file or multifile systems and Ca(OH)2 medication

Abstract This clinical study reports on the antibacterial effects and outcome of endodontic treatment using either a single-file or a multifile system, associated with calcium hydroxide interappointment medication. The root canals of single-rooted teeth with apical periodontitis were treated by using either Reciproc or BioRaCe instrument systems, 2.5% NaOCl irrigation, and calcium hydroxide medication. Bacteriological samples taken before preparation and immediately before obturation were evaluated for total bacterial counts by quantitative real-time polymerase chain reaction (qPCR). Patients were followed up and the treatment outcome was assessed by clinical and radiographic criteria. Decreasing lesions were classified as success in a lenient criterion or failure in a rigid one. Bacteria were detected in all initial samples (47 cases) and were significantly reduced after treatment in both groups (p<0.001). In the Reciproc and BioRaCe groups, 7/25 (28%) and 11/22 (50%) root canals yielded negative qPCR results before obturation, respectively (p>0.05). Quantitative bacterial reduction was similar between groups (p>0.05). The success rate in the BioRaCe group was 95.5% and 77% in the loose and rigid criterion, respectively. In the Reciproc group, corresponding figures were 88% and 76%. Differences in outcome were not significant (p>0.05). No diseased case showed negative qPCR results for bacteria. A difference of >1 Log10 counts was observed between healed and diseased cases. Root canal treatments of teeth with apical periodontitis using a single-file or a multifile system for preparation, associated with NaOCl irrigation and calcium hydroxide interappointment medication, showed similar antibacterial effectiveness and success rate.

Resumo Este estudo clínico relata os efeitos antibacterianos e o resultado de tratamentos endodônticos usando um sistema de instrumentação de instrumento único ou de múltiplos instrumentos, associado à medicação intracanal com hidróxido de cálcio. Os canais radiculares de 80 dentes unirradiculares com lesão perirradicular foram tratados com os sistemas Reciproc ou BioRaCe, irrigação com NaOCl a 2,5% e medicação com pasta de hidróxido de cálcio por 7 a 10 dias. Amostras bacteriológicas foram colhidas antes do preparo e imediatamente antes da obturação e examinadas quanto à contagem total de bactérias pela reação em cadeia da polimerase em tempo real quantitativa (qPCR). Os pacientes foram acompanhados e o resultado do tratamento foi avaliado por critérios clínicos e radiográficos (índice periapical). Os casos com lesões que diminuíram mas não desapareceram foram classificados como sucesso em um critério leniente ou fracasso em um critério rígido. Quarenta e sete pacientes estavam disponíveis para avaliação bacteriológica e de resultados. Bactérias foram detectadas em todas as amostras iniciais desses casos e foram significativamente reduzidas após o tratamento nos dois grupos (p<0,001). Nos grupos Reciproc e BioRaCe, os canais radiculares apresentaram resultados negativos na qPCR em 7/25 (28%) e 11/22 (50%) casos antes da obturação, respectivamente (p>0,05). A redução bacteriana foi semelhante entre os grupos (p>0,05). O período médio (mediana) de acompanhamento foi de 20,5 (18,5) meses para BioRaCe e 17,4 (18) meses para Reciproc (p>0,05). No grupo BioRaCe, a taxa de sucesso foi de 95,5% e 77% nos critérios leniente e rígido, respectivamente. No grupo Reciproc, os valores correspondentes foram 88% e 76%. As diferenças no resultado não foram estatisticamente significativas (p>0,05). Nenhum caso de doença pós-tratamento mostrou resultados negativos de qPCR para bactérias. Foi observada uma diferença >1 Log10 nas contagens bacterianas entre os casos curados e doentes. O tratamento do canal radicular de dentes com lesão perirradicular utilizando um sistema de instrumento único ou múltiplos no preparo, associado à irrigação com NaOCl e medicação entre consultas com hidróxido de cálcio, mostrou eficácia antibacteriana e taxa de sucesso semelhantes.

Cone-beam Computed Tomographic and Micro-computed Tomographic Evaluations of the Root Apexes of Teeth with Posttreatment Apical Periodontitis.

INTRODUCTION: This study evaluated the association of different variables that may influence the outcome of root canal treatment through cone-beam computed tomographic (CBCT) and micro-computed tomography (micro-CT) assessments of root apexes obtained by endodontic microsurgery of teeth with posttreatment apical periodontitis (AP), the agreement between CBCT and micro-CT findings, and the association of these variables with symptoms or lesion size. METHODS: Clinical and CBCT records and root apexes obtained by endodontic microsurgery from 11 cases of symptomatic AP and 22 cases of asymptomatic AP were available. Apical root specimens were further scanned using micro-CT imaging. CBCT parameters included periapical radiolucency size, apical extent/density of root canal filling, and occurrence of procedural errors. Micro-CT images evaluated the same parameters plus the presence of filling material in lateral canals and ramifications, the volume of the filled/nonfilled apical root canal, and the percentage of the nonfilled canal space. The agreement between CBCT/micro-CT observations was evaluated. RESULTS: Mandibular teeth, a lesion size <5 mm, a nonfilled volume <0.04 mm3, and the decreased percentage of the nonfilled canal volume were significantly associated with symptomatic AP. Maxillary teeth and inadequate apical filling density were significantly associated with larger lesions. Agreement between CBCT/micro-CT scores varied from fair (procedural errors) to satisfactory (extent/density of filling). CONCLUSIONS: Tooth location, lesion size, the nonfilled apical canal volume, and the percentage of the nonfilled apical canal volume were associated with symptomatic AP. In addition, lesion size was significantly associated with tooth location and apical root canal filling density. CBCT imaging may not provide a reliable evaluation of procedural errors associated with posttreatment disease.

Cleaning, Shaping, and Disinfecting Abilities of 2 Instrument Systems as Evaluated by a Correlative Micro-computed Tomographic and Histobacteriologic Approach.

INTRODUCTION: This study assessed the cleaning, shaping, and disinfection abilities of 2 instrumentation systems in molar root canals using a novel correlative analytical approach. METHODS: The root canals from extracted mandibular and maxillary molars with apical periodontitis were pair matched according to anatomic similarities as determined by micro-computed tomographic analysis and prepared with either XP-endo Shaper (FKG Dentaire, La Chaux-de-Fonds, Switzerland) (n = 16) or Reciproc Blue (VDW, Munich, Germany) (n = 16) instruments and 2.5% sodium hypochlorite irrigation. Pre- and postpreparation micro-computed tomographic scans were used to identify and calculate the unprepared surface areas (shaping), which were histobacteriologically evaluated for the presence of residual bacteria (disinfection) and pulp tissue remnants (cleaning) in each canal third. RESULTS: Unprepared canal surface areas for XP-endo Shaper and Reciproc Blue in the full canal length were approximately 26% and 19% (P < .05), respectively (30% and 23% in the apical part of the canal, P > .05). Preparation with Reciproc Blue resulted in 37.5% canals free of bacteria in all sections examined and 56% in the apical sections only. XP-endo Shaper resulted in 44% canals free of bacteria in all sections, and 56% in the apical part of the canal only. Pulp tissue remnants were not observed in 31% (all canal sections) and 50% (apical canal sections) of specimens from both instrument systems. No significant differences were observed between instruments when comparing the amount of pulp tissue remnants and the number of cases negative for bacteria and tissue remnants (P > .05). CONCLUSIONS: Although the Reciproc Blue instrument had superior shaping ability in comparison with XP-endo Shaper, both systems performed similarly in cleaning and disinfecting root canals. Irregular canals and difficult-to-reach areas were not thoroughly cleaned and disinfected by any of the tested systems.

Impact of Contracted Endodontic Cavities on Root Canal Disinfection and Shaping.

INTRODUCTION: The impact of minimally invasive endodontic procedures on root canal disinfection has not been determined. This ex vivo study compared root canal disinfection and shaping in teeth with contracted or conventional endodontic cavities. METHODS: Mandibular incisors with oval-shaped canals were selected and anatomically matched based on micro-computed tomographic (micro-CT) analysis and distributed into 2 groups. Conservative and conventional access cavities were prepared, and the canals were contaminated with a pure culture of Enterococcus faecalis for 30 days. Root canal preparation in both groups was performed using the XP-endo Shaper instrument (FKG Dentaire, La Chaux-de-Fonds, Switzerland) and 2.5% sodium hypochlorite irrigation. Intracanal bacteriologic samples were taken before and after preparation, and DNA was extracted and subjected to quantitative polymerase chain reaction. Micro-CT scans taken before and after preparation were used for shaping evaluation. Bacteriologic data were analyzed by the Poisson regression model and the chi-square test with Yates correction. Micro-CT data were analyzed by the Wilcoxon, Mann-Whitney, and Student t tests with the significance level set at 5%. RESULTS: All initial samples were positive for E. faecalis. After preparation, the number of bacteria-positive samples was significantly higher in the contracted cavity group (25/29, 86%) than in the conventional cavity group (14/28, 50%) (P < .01). Intergroup quantitative comparison showed that the reduction in bacterial counts was also significantly higher in the group of conventional cavities (P < .01). Micro-CT data revealed no significant difference in the amount of unprepared areas between groups. CONCLUSIONS: Our findings showed that although shaping using an adjustable instrument was similar between groups, disinfection was significantly compromised after root canal preparation of teeth with contracted endodontic cavities.