Efficacy of a thermally treated single file compared with rotary systems in endodontic retreatment of curved canals: a micro-CT study.

OBJECTIVES: This study aimed to compare WaveOne Gold with ProTaper and RaCe systems regarding remaining filling material, apical transportation (AT), and working time (WT) after (i) filling removal and (ii) shaping of curved canals. METHODS: Thirty mesiobuccal canals of maxillary molars were prepared and filled. After 30 days, they were randomly assigned into three groups (n = 10), according to the instruments used for filling removal and shaping, respectively: WOG-WaveOne Gold Primary and Medium; PTG-ProTaper Retreatment and ProTaper Next; RCG-D-RaCe and RaCe. Micro-CT analysis assessed the residual filling material and AT. WT was recorded. Data were statistically analyzed (α = .05). RESULTS: There was no significant difference between groups in the amount of filling material at any evaluated moment (P > .05). All groups presented low AT values. The WT was similar in all groups in filling removal (P > .05), and in shaping step WOG was faster than PTG and RCG (P < .05). CONCLUSIONS: Neither system could completely remove the filling material. The instruments evaluated were safe and the reciprocating system was faster than the rotary systems in shaping the canals. CLINICAL RELEVANCE: This study provided consistent information on filling material removal capacity of WaveOne Gold. Considering that all tested systems were safe, WaveOne Gold may be an alternative with cost-effectiveness and shorter learning curve for endodontic retreatment.

Radiolucent halos beneath composite restorations do not justify restoration replacement.

PURPOSE: To determine the correlation between the presence of radiolucent areas (RA) beneath composite restorations and gaps and remaining demineralized tissue (RDT). METHODS: 50 extracted teeth (sound and carious) were studied. After caries removal, cavities were filled. Artificial cavities were created and filled in the sound teeth. Samples were sectioned and analyzed with stereomicroscopy. RESULTS: Gap/RDT was observed in 38.9% [95% confidence interval (CI) =28.2-50.5] and 68.9% (95% CI = 57-78.6) of sound and carious teeth, respectively, (P = 0.001). Gap/RDT was associated with RA (P < 0.001). Sensitivity, specificity, predictive positive values (PPV), predictive negative value, and accuracy for carious teeth were 77.1% (95% CI = 63.7-87.3), 54.5% (95% CI = 33.8-74.1), 78.7% (95% CI = 65.3- 88.7), 52.2% (95% CI = 32.1-71.7), and 70% (95% CI = 58.5-79.8), and for sound teeth were 73.7% (95% CI = 62.9-82.6), 59.1% (95% CI = 47.0-70.4), 67.5% (95% CI = 56.9-76.9), 66.1% (95% CI = 53.4-77.3), and 66.9% (95% CI = 58.9-74.3). Only the PPV differed between the sound and carious teeth (P = 0.024).There was a correlation between radiolucency and gap/RDT, but a high number of false positives were found.

Bibliometric analysis and diagnostic efficacy of cone-beam computed tomography studies published in Imaging Science in Dentistry from 2011 to 2022.

Purpose: This bibliometric analysis aimed to provide a comprehensive overview of the characteristics, trends, and level of diagnostic efficacy of studies on cone-beam computed tomography (CBCT) published in Imaging Science in Dentistry (ISD) from 2011 to 2022. Materials and Methods: Publications related to CBCT identified in the electronic collection of ISD were selected according to eligibility criteria by 2 independent reviewers who collected data on the characteristics of the articles (year, authors, and country). The type and topic of studies were analyzed using VOSviewer v.1.6.18 (Centre for Science and Technology Studies, Leiden University, Leiden, Netherlands). The research articles were classified according to the hierarchical scale of diagnostic efficacy. Results: Of the 236 articles included, most were from South Korea and Brazil. Bong-Hae Cho and Yun-Hoa Jung were the most prolific authors on the topic of CBCT. The most frequently published types of studies were cross-sectional and laboratory-based. The most popular topics WERE related to the diagnosis of pathologies and/or alterations, as well as anatomical variations. On the diagnostic efficacy scale, most studies were rated level 1 (technical efficacy) or 2 (diagnostic accuracy efficacy). Conclusion: A steady increase was observed in publications related to CBCT, which are of both clinical and academic interest. The trends in these publications were analyzed, revealing that most are cross-sectional studies primarily exploring the capabilities of CBCT in diagnosing pathologies and/or changes in the oral and maxillofacial complex. These studies were typically classified as level 1 or 2 on the diagnostic efficacy scale.

Azithromycin as an adjunctive treatment of aggressive periodontitis: radiographic findings of a 12-month randomized clinical trial.

PURPOSE: To compare the 12-month radiographic outcomes following the use of azithromycin or placebo as adjuncts to non-surgical periodontal treatment of AgP. METHODS: 17 aggressive periodontitis (AgP) subjects 13-26 years old were randomly assigned to receive scaling and root planing (SRP) with systemic azithromycin or placebo. Standardized radiographs were taken at baseline and 12 months postoperatively. Recall visits consisting of oral prophylaxis and oral hygiene instructions were performed during the 12 months. Digital image subtraction analysis and linear bone measurements were conducted by a blinded and calibrated examiner. Student t-tests were used for within and between-groups comparisons. ANCOVA was applied for between-group comparisons of changes in linear bone level adjusting for baseline values. RESULTS: There were significant gains in linear bone levels in the azithromycin (0.55 +/- 0.10 mm) and placebo (0.42 +/- 0.07 mm) groups between the baseline and 12-month postoperative visits. There were also significant gains in bone density in the two treatment groups. No significant differences were observed between the two treatments in the amount of linear bone gain or bone density during the follow-up period. The use of azithromycin as an adjunct to SRP in the treatment of AgP did not result in significant radiographic bone level changes compared to placebo.

XP Endo Finisher-R and PUI as supplementary methods to remove root filling materials from curved canals.

This study assessed the ability of XP-endo Finisher R (FKG, La Chaux-de-Fonds, Switzerland) to remove filling remnants from curved mesiobuccal canals of maxillary molars, using the passive ultrasonic irrigation (PUI) technique as a comparison. Twenty-four curved main mesiobuccal canals (MB1) of maxillary molars were instrumented with Wave One (#25/07) and filled with gutta-percha points and AH Plus Sealer. Samples were then re-treated with a standardized protocol with Wave One (#35/06) as the master apical file. Micro-CT scans measured baseline volume of remaining filling material (in mm3). Samples were divided into two groups (n = 12) according to the supplementary cleaning approach: (PUI) or XP-endo Finisher R. Statistics compared baseline and final volume of filling material (within-group); and the percentage of filling material reduction (between-group). Mean baseline volumes, final volumes, and percentages of reduction (%) of filling material for XP-endo Finisher R and PUI were respectively: 0.060 mm3, 0.042 mm3, and 31.28%; and 0.064 mm3, 0.054 mm3, and 16.57%. Both tested protocols reduced the amount of filling material (p < 0.05). XP-endo Finisher R had higher percentage of reduction as compared to PUI (p < 0.05). XP-endo Finisher R and PUI used as supplementary cleaning protocols during re-treatment improved the removal of root filling material in curved canals; but XP-endo Finisher R was approximately twice more efficient. The complete filling material removal during re-treatment procedures is still a challenge. Supplementary cleaning protocols may help to remove the remaining material after the complete mechanical preparation of curved canals. XP-endo Finisher R was approximately twice more efficient than PUI.

Physicochemical properties of three bioceramic cements.

This study aimed to compare the physicochemical properties of MTA Angelus (MTA-A), MTA Repair HP (MTA-HP), and Biodentine (BD). Setting times (n = 7) were determined in accordance with ASTM C266-15. Solubility (n = 11), pH (n = 10), and calcium ion release (n = 10) were evaluated up to 28 days in accordance with ANSI/ADA specification no. 57. Radiopacity was assessed by ANSI/ADA (n = 10) and the tissue simulator method (n = 10). In both methods, the specimens were radiographed using an aluminum stepwedge and the digital radiographs were analyzed in Adobe Photoshop, determining the mean grayscale pixel values of the materials, of the 3-mm aluminum stepwedge, and of the dentin, the latter of which was analyzed on the tissue simulator. The data obtained from each test were statistically analyzed and compared (p < 0.05). MTA-A presented longer final setting time compared with the other materials. There were no significant differences in the mass values of materials during the experiment. All materials presented an alkaline pH. BD promoted greater calcium ion release in most of the experimental periods. All materials presented appropriate radiopacity. BD showed lower radiopacity than MTA-A in the tissue simulator method. All groups presented higher radiopacity in the tissue simulator when compared with the ANSI/ADA method. MTA-A, MTA-HP, and BD showed appropriate physicochemical properties and radiopacity, and were considered suitable to be used in clinical practice.

The unplanned and unequal expansion of Dentistry courses in Brazil from 1856 to 2020.

This study analyzed the consequences of the disordered expansion of Dentistry courses on the distribution of professionals, the job market, and limitations of the National System of Higher Education Assessment (SINAES) developed as a guarantee of education quality. This observational, descriptive, and analytical study used secondary data from several official databases. The number of courses was obtained from the e-MEC registry. From the Higher Education Census, the study collected historical series of courses offered, number of candidates per open seat, number of individuals who initiated and completed the course, and information about professors in the public and private schools. The reports related to Dentistry courses from the National Health Council were also analyzed. The performance of undergraduate students was assessed from synthesis reports of Enade from 2004 to 2016. The number of dentists and their regional distribution was based on the Federal Dental Council, and Brazilian population and gross domestic product were collected from the Brazilian Institute of Geography and Statistics. Dentistry courses in Brazil grew exponentially from 1856 to 2020; among the 544 authorized courses, 82 currently have not yet started their activities. The fast expansion of courses in Brazil has worsened the regional asymmetries in the supply of dentist, and the SINAES has not been able to fully assure the quality of Dentistry courses. Brazilian dentistry, which has increased its scientific and technological development since the 19th century, with outstanding intellectual production, is at risk of a collapse due to a plethora of dentists.

Retorno das atividades presenciais nos cursos de Odontologia brasileiros na pandemia de COVID-19: comparação entre instituições públicas e privadas / Retorno de las actividades presenciales en los cursos de Odontología brasileños durante la pandemia de COVID-19: comparación entre instituciones públicas y privadas / Return of on-site activities in Brazilian Dentistry courses during the COVID-19 pandemic: comparison between public and private institutions

Trata-se de estudo quanti-qualitativo que analisa o retorno das atividades presenciais nos cursos de Odontologia brasileiros, durante a pandemia de COVID-19, e as dificuldades enfrentadas, comparando instituições públicas e privadas. Um formulário on-line com questões abertas e fechadas foi encaminhado por e-mail aos representantes dos cursos de Odontologia, de março a junho de 2021. Foram incluídos os cursos cadastrados no sitee-MEC iniciados até 2017. A análise quantitativa utilizou os testes qui-quadrado, exato de Fisher e t de Student(p<0,05); uma questão aberta foi submetida à análise temática de conteúdo. Dos 329 cursos elegíveis, foram respondidos 83 formulários (21 públicos e 62 privados). Os cursos de instituições públicas apresentaram menor frequência de retorno das atividades presenciais até a data da coleta (p=0,038), inclusive com maior proporção de suspensão das atividades clínicas e laboratoriais (p≤0,001), mas sem diferença para aulas teóricas remotas (p>0,05). Os cursos privados demonstraram ter maior disponibilidade de recursos para o retorno presencial, tais como: estrutura, funcionários e docentes (p<0,001). Apesar das normas de biossegurança constituírem um desafio comum, as principais dificuldades relatadas nas instituições privadas diante do retorno das atividades presenciais foram a modulação ou escalonamento das turmas e ambientes de aula, controle do fluxo de pessoas e implantação de protocolos. Nas públicas, destacam-se dificuldades relacionadas à adequação da estrutura e aquisição de materiais. Conclui-se que a maioria dos cursos de Odontologia havia retomado às aulas no início de 2021, mas as instituições privadas apresentaram maior proporção de retorno às atividades laboratoriais e clínicas presenciais (AU).

Se trata de un estudio cuantitativo y cualitativo que analiza el retorno de las actividades presenciales en las carreras de Odontología brasileñas, durante la pandemia de COVID-19, y las dificultades enfrentadas, comparando instituciones públicas y privadas. Se envió por correo electrónico un formulario en línea con preguntas abiertas y cerradas a los representantes de los cursos de Odontología, de marzo a junio de 2021. Se incluyeron los cursos registrados en el sitio web de e-MEC que iniciaron hasta el año 2017. El análisis cuantitativo utilizó las pruebas chi-cuadrado, Fisher exacta y t de Student (p<0,05); se sometió una pregunta abierta al análisis de contenido temático. De los 329 cursos elegibles, se completaron 83 formularios (21 públicos y 62 privados). Los cursos de instituciones públicas mostraron una menor frecuencia de retorno a actividades presenciales hasta la fecha de cobro (p=0,038), incluyendo una mayor proporción de suspensión de actividades clínicas y de laboratorio (p≤0,001), pero sin diferencia para clases teóricas remotas (p >0.05). Los cursos privados demostraron mayor disponibilidad de recursos para el retorno presencial, tales como: estructura, personal y docentes (p<0,001). Si bien los estándares de bioseguridad constituyen un desafío común, las principales dificultades reportadas en las instituciones privadas ante el regreso de las actividades presenciales fueron modular o escalonar clases y ambientes de aula, controlar el flujo de personas e implementar protocolos. En las públicas destacan dificultades relacionadas con la adecuación de la estructura y adquisición de materiales. Se concluye que la mayoría de las carreras de Odontología habían retomado clases a inicios de 2021, pero las instituciones privadas tuvieron una mayor proporción de retorno a las actividades presenciales de laboratorio y clínicas (AU).

This is a quantitative-qualitative study analyzing the return of on-site activities in Brazilian dentistry undergraduate courses during the COVID-19 pandemic and the difficulties faced, comparing public and private institutions. An online form with open and multiple-choice questions was sent via e-mail to the representatives of dentistry courses from March to June 2021. The courses included were those registered on the e-MEC webpage that had started up to 2017. The quantitative analysis employed the chi-square, the Fisher exact, and the T student tests (p<0.05); the open question was subjected to thematic content analysis. Out of the 329 eligible courses, 83 forms were answered and returned (21 public and 62 private). Public institution courses showed lower frequency of return to on-site activities up tothe data collection (p=0.038), and presented higher proportion of suspension of clinical and laboratory activities (p≤0.001), but no difference regarding remote theoretical lessons (p>0.05). Private courses showed higher availability of resources supporting the return to on-site activities, namely, structure, workers, and professors (p<0.001). Although biosafety norms presented a common challenge, the main difficulties reported in private institutions related to the return to on-site activities were the modulation and schedule of the classes and lesson environments, controlling the flow of people, and the implementation of protocols. Public institutions highlighted difficulties related to adjustment of the structure and material acquisition. The results showed that most dentistry courses had returned to on-site lessons in the early 2021, but private institutions reported higher proportion of return to on-site laboratory and clinical activities (AU).

Canal transportation after root canal instrumentation: a comparative study with computed tomography.

This in vitro study used computed tomography (CT) to compare the occurrence of canal transportation in the apical third of mesiobuccal canals in maxillary molars instrumented with 3 techniques. Sixty teeth were assigned to 3 groups (n = 20), and the root canals were instrumented as follows: Group 1, hand instrumentation with K-files; Group 2, K-files coupled to an oscillatory system powered by an electric engine; Group 3, ProTaper NiTi rotary system powered by an electric engine. To compare the canal transportation produced by the different techniques, preinstrumentation and postinstrumentation 3-dimensional CT images were obtained from root cross-sections of the region located 3 mm short of the apical foramen of each root canal. The CT scans were exported to Adobe Photoshop software, and the initial and final images were superimposed to detect the root canal wall differences between them. Canal transportation was measured by the distance between the prepared canal center and the anatomic canal center. The manual technique produced lesser canal transportation (0.10 mm) than the oscillatory and rotary techniques (0.37 and 0.22 mm, respectively); this difference was statistically significant (P=.021). All studied techniques produced canal transportation.

The role of psychoneuroimmune interactions in the pathogenesis of ligature-induced periodontal disease in Wistar rats.

The aim of the present study was to determine the role of chronic stress in the pathogenesis of ligature-induced periodontal disease in rats. Fifty-three Wistar rats were randomly assigned to 4 experimental groups: 1--ligature; 2--ligature + stress; 3--stress only; 4--control. After 30 days the animals were sacrificed, blood samples were collected and histological sections were made for histometric analysis. The stress parameters evaluated were weight of thymus, spleen, adrenal glands and plasma glucocorticoid levels. Analysis of adrenal glands showed statistically significant differences between stressed and non-stressed groups (one-way ANOVA, p < 0.05). Plasma glucocorticoid levels were higher in Group 3 and lower in Group 2 (81.1 nmol/I versus 62.5 nmol/l, p < 0.05). Histometric measurements from the bone crest and from the first attached fiber were taken for all groups and for Groups 1 and 2 for the sites with and without ligatures. The ligature sites always displayed higher mean values than non-ligated sites (paired sample t test, p < 0.05). No statistically significant differences were observed between Groups 1 and 2 with regard to the ligated sites. However, differences were observed between Groups 1 and 2 in histometric bone levels in the non-ligated sites (mean values of 0.81 and 0.55 mm, respectively, p < 0.05). It may be concluded that stress can have a possible role in the activation of the hypothalamus-pituitary-adrenal (HPA) axis, with different levels of glucocorticoid release.

Apical Transportation, Centering Ratio, and Volume Increase after Manual, Rotary, and Reciprocating Instrumentation in Curved Root Canals: Analysis by Micro-computed Tomographic and Digital Subtraction Radiography.

INTRODUCTION: This study aimed to evaluate apical transportation (AT), centering ratio (CR), and volume increase (VI) produced after instrumentation of mesiobuccal canals of maxillary molars with hand files, rotary, and reciprocating instruments using micro-computed tomographic (micro-CT) imaging and to demonstrate the ability of digital subtraction radiography (DSR) to evaluate AT. METHODS: Forty-five canals were randomly assigned to either group K, manual K-files; PTN, ProTaper Next (Dentsply Maillefer, Ballaigues, Switzerland); or Rec, Reciproc (n = 15 for each group) for preparation. Master apical files were #25, X2 (#25/06), and R25 (#25/08), respectively. Micro-CT imaging was used to measure AT (mm) and CR (mm) at 3 different locations (1, 4, and 7 mm from the apex). VI (mm3) was measured for each root third and for the whole canal. DSR (mesiodistal and buccolingual projections) was used to measure AT at 1 mm from the apex. RESULTS: AT and CR values were statistically similar across the groups at 1, 4, and 7 mm. AT results obtained for the different locations were similar within each group; CR, in turn, showed statistically lower values at 1 mm. VI was statistically similar in all groups. Both DSR and micro-CT imaging showed that AT always occurred on the outside of canal curvature. The highest mean value obtained for AT was 0.215 mm. CONCLUSIONS: AT, CR, and VI were similar for the K, PTN, and Rec groups. AT results were clinically irrelevant. DSR was as effective as micro-CT imaging in AT analysis and could be considered as an alternative method for assessing this outcome.

Radiopacity Evaluation of Gutta-Percha Points in Thinner Samples than the ANSI/ADA Recommendation.

The aim of this study was to evaluate the radiopacity of different gutta-percha points (Endo Points®, Dentsply®, Tanari®, Meta®, Roeko® and Odous®) in samples of 1 mm thick as established by ANSI/ADA Specification #57 and ISO 6876/2001, in comparison with thinner samples. Twelve test specimens for each material, four for each thickness (0.3, 0.6, and 1 mm and diameter of 8 mm), were laminated and compressed between two polished glass plates until the desirable thickness. Digital radiographs were obtained along with a graduated aluminum stepwedge varying from 1 to 10 mm in thickness. The X-ray unit was set at 70 kVp, 10 mA and 0.4 s exposure time, at a focal distance of 36 cm. One calibrated observer quantified the average values of pixels with Adobe Photoshop® software. Data were analyzed using ANOVA and Tukey tests, at 5% significance level. At 0.6 and 1 mm thickness, all the tested materials showed radiopacity higher than 3 mm of aluminum (reference value). At 0.3 mm thickness, Odous and Tanari presented significantly less radiopacity than the reference, and the other materials showed similar radiopacity to the reference. The study concluded that the materials demonstrated different radiopacities and all had values above the minimum recommended by ANSI/ADA specification #57, being Odous and Tanari less radiopaque than the reference value in thinner samples (0.3mm).

Physicochemical properties of three bioceramic cements

Abstract: This study aimed to compare the physicochemical properties of MTA Angelus (MTA-A), MTA Repair HP (MTA-HP), and Biodentine (BD). Setting times (n = 7) were determined in accordance with ASTM C266-15. Solubility (n = 11), pH (n = 10), and calcium ion release (n = 10) were evaluated up to 28 days in accordance with ANSI/ADA specification no. 57. Radiopacity was assessed by ANSI/ADA (n = 10) and the tissue simulator method (n = 10). In both methods, the specimens were radiographed using an aluminum stepwedge and the digital radiographs were analyzed in Adobe Photoshop, determining the mean grayscale pixel values of the materials, of the 3-mm aluminum stepwedge, and of the dentin, the latter of which was analyzed on the tissue simulator. The data obtained from each test were statistically analyzed and compared (p < 0.05). MTA-A presented longer final setting time compared with the other materials. There were no significant differences in the mass values of materials during the experiment. All materials presented an alkaline pH. BD promoted greater calcium ion release in most of the experimental periods. All materials presented appropriate radiopacity. BD showed lower radiopacity than MTA-A in the tissue simulator method. All groups presented higher radiopacity in the tissue simulator when compared with the ANSI/ADA method. MTA-A, MTA-HP, and BD showed appropriate physicochemical properties and radiopacity, and were considered suitable to be used in clinical practice.

XP Endo Finisher-R and PUI as supplementary methods to remove root filling materials from curved canals

Abstract: This study assessed the ability of XP-endo Finisher R (FKG, La Chaux-de-Fonds, Switzerland) to remove filling remnants from curved mesiobuccal canals of maxillary molars, using the passive ultrasonic irrigation (PUI) technique as a comparison. Twenty-four curved main mesiobuccal canals (MB1) of maxillary molars were instrumented with Wave One (#25/07) and filled with gutta-percha points and AH Plus Sealer. Samples were then re-treated with a standardized protocol with Wave One (#35/06) as the master apical file. Micro-CT scans measured baseline volume of remaining filling material (in mm3). Samples were divided into two groups (n = 12) according to the supplementary cleaning approach: (PUI) or XP-endo Finisher R. Statistics compared baseline and final volume of filling material (within-group); and the percentage of filling material reduction (between-group). Mean baseline volumes, final volumes, and percentages of reduction (%) of filling material for XP-endo Finisher R and PUI were respectively: 0.060 mm3, 0.042 mm3, and 31.28%; and 0.064 mm3, 0.054 mm3, and 16.57%. Both tested protocols reduced the amount of filling material (p < 0.05). XP-endo Finisher R had higher percentage of reduction as compared to PUI (p < 0.05). XP-endo Finisher R and PUI used as supplementary cleaning protocols during re-treatment improved the removal of root filling material in curved canals; but XP-endo Finisher R was approximately twice more efficient. The complete filling material removal during re-treatment procedures is still a challenge. Supplementary cleaning protocols may help to remove the remaining material after the complete mechanical preparation of curved canals. XP-endo Finisher R was approximately twice more efficient than PUI.

The unplanned and unequal expansion of Dentistry courses in Brazil from 1856 to 2020

Abstract: This study analyzed the consequences of the disordered expansion of Dentistry courses on the distribution of professionals, the job market, and limitations of the National System of Higher Education Assessment (SINAES) developed as a guarantee of education quality. This observational, descriptive, and analytical study used secondary data from several official databases. The number of courses was obtained from the e-MEC registry. From the Higher Education Census, the study collected historical series of courses offered, number of candidates per open seat, number of individuals who initiated and completed the course, and information about professors in the public and private schools. The reports related to Dentistry courses from the National Health Council were also analyzed. The performance of undergraduate students was assessed from synthesis reports of Enade from 2004 to 2016. The number of dentists and their regional distribution was based on the Federal Dental Council, and Brazilian population and gross domestic product were collected from the Brazilian Institute of Geography and Statistics. Dentistry courses in Brazil grew exponentially from 1856 to 2020; among the 544 authorized courses, 82 currently have not yet started their activities. The fast expansion of courses in Brazil has worsened the regional asymmetries in the supply of dentist, and the SINAES has not been able to fully assure the quality of Dentistry courses. Brazilian dentistry, which has increased its scientific and technological development since the 19th century, with outstanding intellectual production, is at risk of a collapse due to a plethora of dentists.

The effectiveness of rotary and reciprocating techniques in curved root canals retreatment: a micro- CT analysis

Introduction: Different NiTi rotary systems have been developed to improve efficiency and retreatment success rates. Aim: To evaluate the Protaper Universal retreatment system and WaveOne instrument in removing the filling material from curved canals during retreatment. Materials and Methods: Thirty mesial root canals of extracted human mandibular molar teeth were randomly allocated into 2 groups (n=15). In the PT group, retreatment was performed with ProTaper Universal Retreatment according to the manufacturer's instructions. In the WO group, was used WaveOne Primary. ProTaper Universal F2 and F3 were used to achieve the apical diameter in both groups. The samples were scanned by micro-computed tomography pre and postoperatively to evaluate the filling material remaining. The percentage of material filling was compared between groups using Student's T test and in the same group among thirds was compared using Kruskal-Wallis followed by Dunn's post hoc test. Results: The filling material remaining was not statistically different between the groups (p≥0.05). The apical third presented a greater amount of remaining filling material when compared with the cervical third for both groups (p<0.05). Conclusion: Rotary and reciprocating techniques can effectively, but not completely, remove the filling materials from the root canal system. The apical third presented a more significant amount of remaining filling material.

Brazilian dentistry courses facing the COVID-19 pandemic / Cursos de Odontologia brasileiros frente à pandemia COVID-19

The study aimed to analyze the situation of Brazilian dental education considering the exceptionality of the COVID-19pandemic.An observational and analytical study was conducted with two cross-sections, using questionnaires sent to all course coordinators in Brazil, in the 1st semester of 2020 and in March 2021.At onset of the pandemic, the institutions interrupted on-site activities. There was significant association between private institutions and offering remote lectures and using these resources before the pandemic. The public sector was associated with not teaching remote lecturesand not using these resources previously. Public institutionshad a greater degree of difficulty in the use and access to technologies for online activitiesby professors and students, as well as a lower degree of preparation in relation to biosecurityprotocols to resume the clinical activities. Impacts were identified in different dimensions of dental education related to the development of practical activities and the establishment of new biosecurityprotocols. Nearly all private coursesdid not suspend activities or did it for less than one month and resumed clinical or laboratory activities at some point during the surveyed period, while public institutions required an average of 5 months for such reorganization.The COVID-19 pandemic substantially increased the use of digital media in Braziliandental education. From this assessment, there arefinancial limitations of the public sector to adapt the infrastructure to the requirements of the current biosecurityprotocols. In general, students are receiving support from the institutionand the coordinators identified negative impacts in different dimensions of dental education, notably in the establishment of new biosecurityprotocols, adequacy in the physical structure and teaching-learning process (AU).

O estudo teve como objetivo analisar a situação da educação odontológica brasileira considerando a excepcionalidade da pandemia COVID-19. Foi realizado um estudo observacional e analítico com dois cortes transversais, por meio de questionários enviados a todos os coordenadores de curso no Brasil, no 1º semestre de 2020 e em março de 2021. No início da pandemia, as instituições interromperam as atividades presenciais. Houve associação significativa entre as instituições privadas e a oferta de aulasremotas e o uso desses recursos antes da pandemia. O setor público foi associado a não ministrar aulasa distância e não utilizar esses recursos anteriormente. As instituições públicas apresentaram maior grau de dificuldade no uso e acesso às tecnologias para atividades on-line por professores e estudantes, bem como menor grau de preparo em relação aos protocolos de biossegurança para a retomada das atividades clínicas. Foram identificados impactos em diferentes dimensões da formação odontológica relacionadas ao desenvolvimento de atividades práticas e ao estabelecimento de novos protocolos de biossegurança. Quase todos os cursos privados não suspenderam as atividades ou o fizeram por menos de um mês e retomaram as atividades clínicas ou laboratoriais em algum momento do período pesquisado, enquanto as instituições públicas necessitaram em média de 5 meses para tal reorganização. A pandemia COVID-19 aumentou substancialmente o uso de recursosdigitaisna educação odontológica brasileira. Existem limitações financeiras do setor público para adaptar a infraestrutura aos requisitos dos atuais protocolos de biossegurança. Em geral, os estudantesestão recebendo apoio da instituição e os coordenadores identificaram impactos negativos em diferentes dimensões do ensino odontológico, notadamente no estabelecimento de novos protocolos de biossegurança, adequação da estrutura física e processo de ensino-aprendizagem (AU).

Association between dental caries and obesity evaluated by air displacement plethysmography in 18-year-old adolescents in Pelotas, Brazil.

OBJECTIVES: To investigate the association between dental caries and obesity, evaluated by air displacement plethysmography, among 18-year-old adolescents from a birth cohort in the city of Pelotas, Brazil. METHODS: A cross-sectional study nested in a birth cohort study was conducted in Pelotas, Brazil. A random sample of 986 18-year-old adolescents was selected. The outcome variable was the occurrence of dental caries (DMFT ≥ 1) according to clinical examination by a trained and calibrated dentist. For the exposure variable (obesity), body fat percentage was measured using air displacement plethysmography and classified as normal weight (P95). Sociodemographic and behavior variables were collected using a questionnaire. We performed multivariable Poisson regression analyses with robust variance to examine the association between dental caries and obesity. RESULTS: DMFT ranged from 0 to 19; mean (SD) was 2 (2.3), and median (P25-P75) was 1 (0-3). Body fat percentage ranged from 0.9 to 57.6%; mean (SD) percentage was 24.4% (11.6%), and median (P25-P75) was 25.1% (14.0-32.9%). The prevalence of dental caries was 66.5% (95% CI 63.6-69.5%), being significantly higher in female adolescents with lower maternal education, lower education, and sugar intake more than once a day. There were no differences in the probability of dental caries among individuals with normal weight, overweight, or obesity in the unadjusted model (P = 0.846) or after adjustment for sociodemographic (P = 0.864) variables. CONCLUSIONS: Overweight and obesity were not associated with the occurrence of dental caries in 18-year-old adolescents.

Apical root canal transportation and remaining dentin thickness associated with ProTaper Universal with and without PathFile.

INTRODUCTION: This study aimed to compare, using digital subtraction radiography, apical transportation in mesiobuccal root canals of extracted human maxillary molars instrumented with ProTaper Universal F3 and F4 files (Dentsply Maillefer, Ballaigues, Switzerland) with and without the prior creation of glide paths using the PathFile system and to compare, using cone-beam computed tomographic imaging, remaining dentin thickness (RDT) after complete preparation. METHODS: Forty mesiobuccal roots with curvatures of 20°-35° were used. In group A, glide paths were created with PathFile #1, #2, and #3 to the working length; in group B, no glide paths were used. All canals were instrumented up to F4 to the working length. Digital subtraction radiographic images were obtained in buccolingual and mesiodistal directions. Apical transportation associated with F3 or F4 was calculated based on the difference between the tip of the first and the last instrument analyzed in each group. RDT was calculated based on cone-beam computed tomographic images. RESULTS: Apical transportation was higher after F4 regardless of the use of the PathFile system. No statistically significant differences between groups A and B were observed in apical transportation after instrumentation with F3 or F4 (P > .05). Group A showed greater RDT values at 2 (buccal and mesial walls, P < .05) and 3 mm (buccal and distal walls, P < .05) from the apex but not at 1 mm. CONCLUSIONS: The use of the PathFile system before root canal preparation with ProTaper Universal F3 and F4 did not influence apical transportation but was associated with greater RDTs at 2 and 3 mm from the apex.

Second canal in mesiobuccal root of maxillary molars is correlated with root third and patient age: a cone-beam computed tomographic study.

INTRODUCTION: There is little evidence supporting the use of cone-beam computed tomographic (CBCT) scanning in root canal anatomy investigation. This study aimed to investigate the presence of second mesiobuccal canals (MB2) in different thirds of the mesiobuccal root of first and second maxillary molars using CBCT scanning and to correlate findings with patient sex and age. METHODS: A total of 100 male and female adult patients with healthy, untreated, well-developed maxillary molars were enrolled. A total of 343 teeth were analyzed in vivo using CBCT scanning: 79 right and 79 left maxillary first molars (1MR and 1ML) and 94 right and 91 left maxillary second molars (2MR and 2ML). Teeth with 3 roots were identified, and the presence of MB2 canals in different thirds was correlated with patient sex and age. RESULTS: Maxillary molars with 3 roots showed a high percentage of MB2 canals: 1MR, 86.1%; 1ML, 91.0%; 2MR, 87.5%; and 2ML, 79.3%. MB2 canals were less prevalent in the middle and apical thirds than in the coronal third. There were no significant associations between the overall presence of MB2 canals and patient sex. Older age (ie, 51-70 years) was associated with fewer canals in 1ML and 2ML. All age groups showed fewer MB2 canals in the apical versus the coronal third. CONCLUSIONS: The prevalence of MB2 canals decreases as the root canal approaches the apical third and as age increases. No association with sex was observed. CBCT scanning proved effective in mapping MB2 canals present in different thirds of the root.