In vitro and in situ caries-preventive effect of a new combined fluoride and calcium experimental nanocomposite solution

Abstract To assess the in vitro and in situ effect of experimental combined fluoride and calcium nanocomposite solutions on dental caries prevention. Nanocompound mesoporous silica (MS) with calcium (Ca) and sodium fluoride (NaF) - (MSCaNaF); MS with NaF (MSNaF), NaF solution (positive control), and deionized water (negative control - CG) were studied. The specimens (n=130) were submitted in vitro to a multispecies biofilm in the presence of 2% sucrose. After 24 h and 48 h, the culture medium pH, the percent of surface mineral loss (%SML), and lesion depth (ΔZ) were analyzed. In the in situ study, 10 volunteers participated in four phases of 7-days each. The products were applied on the specimens (n=240) before 20% sucrose solution drips. The polysaccharides (SEPS and IEPS), %SML and roughness (Sa) were evaluated. There was an in vitro decrease in pH values in 24h and 48h, compared to baseline. The MSCaNaF and MSNaF groups obtained lower values of %SML and ΔZ (p < 0.05) than CG and NaF after 24h and were similar to NaF after 48h (p<0.05). In situ results showed similar SEPS and IEPS among all groups after 48h. An after 7-days, the nanocomposites had similar values (p>0.05), while NaF was similar to CG (p>0.05). After 48h, the MSCaNaF and MSNaF reduced the %SML (p<0.05). After 7-days, both experimental nanocomposites were similar to NaF (p>0.05). Regarding Sa, MSCaNaF was better than NaF for both periods (p<0.05). The nanocomposites controlled the in vitro and in situ enamel demineralization, mainly in the initial periods.

Comparison Between Radiographs, White and Fluorescent Images in the Diagnosis and Treatment Decisions for Occlusal Caries: An Ex Vivo Study

ABSTRACT Objective: To compare the agreement of images in white light (WL), fluorescence (FL), and digital radiographs (DR), on the diagnosis and treatment decisions for occlusal caries lesions against a micro-CT gold standard. Material and Methods: Ten extracted third molars, with enamel and/or dentin caries (ICDAS 2-4), were included. Occlusal surface images were acquired with an intraoral camera (SoproLife®) in WL and FL modes. DR was obtained using an intraoral X-ray and a semi-direct digital system. A total of 780 images were needed, organized in a template, to be later examined by twenty-six dentists invited to compose the study. The Generalized Estimation Equations model was used to compare the proportions of the correct answers between the three methods and the gold standard. When significant, Bonferroni post-hoc test was used to identify differences (α=5%). Results: Most of the examiners were specialists (76.9%) with 14.5 years of experience. All diagnostic methods were similar and showed low agreement (DR 12.7%, WL 16.5%, and FL 16.5%) compared with gold standard caries diagnostic scores. Regarding treatment decisions, mean agreement for all diagnostic methods was higher (43.2%; p<0.001), and among all methods, WL (48.1%) and FL (51.2%) modes performed better than DR (30.4%, p<0.001). Conclusion: SoproLife® images could help clinicians to propose rational, minimally invasive treatments for occlusal caries lesions.

Caregivers' Sense of Coherence and Untreated Dental Caries in Children and Adolescents: A Cross-Sectional Study

ABSTRACT Objective: To associate caregivers' sense of coherence (SOC) and untreated caries with oral health status in children covered by a dental public health system. Material and Methods: A convenience sample of caregivers/children in Angra dos Reis, Brazil, was surveyed. Caregivers' SOC was evaluated using the 13-question version questionnaire. For both caregivers/children, sociodemographic information was acquired and caries experience was evaluated by DMFT/dmft and PUFA/pufa index. Statistical associations between children's untreated carious teeth and interest variables from the caregivers were evaluated by binary logistic regression assessed by generalized linear modeling. Results: A total of 233 pairs of caregivers-children were included. Children's untreated permanent and primary carious teeth represented 34.8% and 62.2% of the caries experience, respectively and at least one PUFA/pufa scored tooth was detected in 22.7% of them. Caregivers' DMFT was 13.5±7.0, while 33.6% scored on PUFA. A total of 62.1% of them presented untreated carious lesions. Results from the univariate model, correlating children's untreated caries and caregivers' attributes showed a statistical significance for SOC values (p<0.015), untreated decayed teeth (p<0.035), self-perception of oral health (p<0.022) and oral impact on daily performance (p<0.010). The multivariate logistic first model kept the statistical significance only for the caregiver's untreated decayed teeth. Conclusion: Caregivers' SOC and untreated carious teeth could be used as indicators of dental treatment needs in their offspring.

Efficacy of 30% and 38% Silver Diamine Fluoride in Arresting Caries Lesions After Different Application Times: An in Vitro Study

Abstract Objective: To evaluate the efficacy of silver diamine fluoride (SDF) in arresting dentin caries lesions when applied under different concentrations and times. Material and Methods: Forty-two bovine blocks were selected and fixed in 24-well plates. Each well received a mixed bacterial inoculum added to the culture medium with 5% sucrose. The plates were incubated in microaerophilia (7 days) for caries formation, confirmed by micro-CT (M1). SDF was applied over the carious lesions for different times and concentrations (n=6): SDF 30% - immediate removal, 1 minute and 3 minutes; SDF 38%, - immediate removal, 1 minute and 3 minutes. The group without treatment was the control. Then, the samples were again scanned by micro-CT (M2) and submitted to a second cariogenic challenge for 21 days. Then, a final scan was performed (M3). Results: Mean pH at the culture medium and lesion depth were compared using Kruskal-Wallis and Wilcoxon tests. 38% SDF showed the lowest metabolic activity of the biofilm. All 38% groups and 30% 1 and 3 minutes did not show an increase in mean lesion depth comparing M3 with M1. However, only 30% 3 minutes and 38% 1 and 3 minutes showed a significant reduction of lesion depth. Conclusion: The minimum application time of 30% SDF to arrest dentin caries lesion was 1 minute, while 38% SDF arrested with application and immediate removal.

Association Between Caries Experience and School Performance in an Island Community: Full-Time versus Part-Time Public Schools

Abstract Objective: To investigate the association between caries experience and school performance among children and adolescents living in an island community without fluoridated water supply and to compare data according to the type of attended school (full-time or part-time). Material and Methods: A cross-sectional oral health survey in a convenience sample of students (n=147) attending four public schools was performed. Students were examined by one calibrated dentist in the school environment to the obtain prevalence of dental caries (DMFT/dmft) and its consequences using the PUFA/pufa index. Self-reported oral health behavior was also accessed. Data from each student's school performance and absenteeism were extracted from official sources and the school performance was classified into "good" and "fair". The final sample consisted of 120 students. Descriptive statistics, Mann-Whitney, Kruskal-Wallis, chi-square tests and binary logistic regression were performed to evaluate collected data. Results: Students´ age ranged between 5 to 19 years (10±4.3). DMFT/dmft mean were 1.3 (±2.3) and 3.05 (±3.4), respectively. Conclusion: Participants from the full-time school presented better oral health status than their peers in the part-time schools (p<0.05). A significant association was found between the prevalence of caries-free participants and good school performance when the factor age range was controlled (OR=2.87). Moreover, attendance to full-time schools appeared to be a protective factor for good oral health conditions (AU).

In vitro effect of experimental nanocomposites solutions on the prevention of dental caries around orthodontic brackets

Abstract This study aimed to evaluate the in vitro effect of a single application of experimental nanocomposite solutions on the prevention of dental caries around orthodontic brackets. The specimens were exposed to mesoporous silica (MS) nanocomposites containing fluoride by association with titanium tetrafluoride (TiF4) or sodium fluoride (NaF). Nanocomposites also could contain calcium and groups were described as MSCaTiF4, MSTiF4, MSCaNaF, MSNaF, and controls (TiF4, and NaF). Specimens were subjected to the formation of a multispecies biofilm to generate a cariogenic challenge. After 24h, both pH and total soluble fluoride concentration of the culture medium were assessed. Mineral loss was evaluated by percentage of surface mineral loss (%SML), mineral volume variation (ΔZ) of inner enamel and polarized light microscopy (PL). Linear (Ra) and volumetric (Sa) surface roughness and scanning electronic microscopy (SEM) were used to assess enamel topography. Statistical analyses were conducted considering p<0.05. MSNaF had the highest value of culture medium pH after cariogenic challenge, similarly to MSTiF4. All nanocomposite solutions released less fluoride than their controls NaF and TiF4 (p<0.05). All nanocomposite solutions presented lower %SML compared to their respective control groups (p<0.05). Lower Ra, Sa and ΔZ were observed for experimental groups compared to TiF4 (p<0.05). The results were confirmed by PL and SEM analysis. The experimental nanocomposite solutions contributed for lower enamel demineralization around orthodontic brackets.

RESUMO Este estudo teve como objetivo avaliar o efeito in vitro de uma única aplicação de soluções experimentais de nanocompósitos na prevenção de cárie dentária em braquetes ortodônticos. Os espécimes foram expostos a nanocompósitos de sílica mesoporosa (MS) contendo fluoreto por associação com tetrafluoreto de titânio (TiF4) ou fluoreto de sódio (NaF). Os nanocompósitos também podem conter cálcio e os grupos foram descritos como MSCaTiF4, MSTiF4, MSCaNaF, MSNaF e controles (TiF4 e NaF). Os espécimes foram submetidos à formação de um biofilme multiespécie para gerar um desafio cariogênico. Após 24h, o pH e a concentração de flúor solúvel total do meio de cultura foram avaliados. A perda mineral foi avaliada pela porcentagem de perda mineral superficial (% SML), variação do volume mineral (ΔZ) do esmalte interno e microscopia de luz polarizada (PL). A rugosidade superficial linear (Ra) e volumétrica (Sa) e a microscopia eletrônica de varredura (MEV) foram utilizadas para avaliar a topografia do esmalte. As análises estatísticas foram realizadas considerando p <0,05. MSNaF apresentou o maior valor de pH do meio de cultura após o desafio cariogênico, semelhante ao MSTiF4. Todas as soluções de nanocompósitos liberaram menos flúor do que seus controles NaF e TiF4 (p <0,05). Todas as soluções de nanocompósitos apresentaram% SML menor em comparação com seus respectivos grupos de controle (p <0,05). Ra, Sa e ΔZ menores foram observados para os grupos experimentais em comparação ao TiF4 (p <0,05). Os resultados foram confirmados por análises PL e SEM. As soluções experimentais de nanocompósitos contribuíram para a menor desmineralização do esmalte ao redor dos braquetes ortodônticos.

Protocolo de pulpectomia para dentes decíduos: um guia clínico e prático baseado em evidências científicas / Pulpectomy protocol for primary teeth: a clinical and practical guide based on scientific evidence

O procedimento de pulpectomia em dentes decíduos consiste na remoção total do tecido pulpar com inflamação irreversível ou com necrose, preparo químicomecânico e obturação com material reabsorvível, com o intuito de manter o dente o maior tempo possível na cavidade bucal, devolvendo função e saúde para o paciente infantil. Existem vários protocolos descritos na literatura, no entanto, não há consenso entre eles e poucos possuem acesso livre. Sendo assim, observa-se carência de um guia clínico e prático para nortear o cirurgião-dentista na realização desse procedimento durante o atendimento odontopediátrico. Portanto, o intuito deste trabalho é apresentar aos clínicos um protocolo de pulpectomia com altas frequências de sucesso clínico e radiográfico, baseado em evidências científicas, desenvolvido e aplicado pelo Grupo de Pesquisa de Endodontia em Odontopediatria da Universidade Federal do Rio de Janeiro (GEDOPED-UFRJ). O presente protocolo contempla indicações, contraindicações, tática operatória, materiais necessários e orientações para acompanhamento. Com esta publicação de maneira gratuita, de acesso livre e no idioma dominante do país, espera-se ampliar o alcance de odontopediatras e clínicos gerais que atendem crianças a um tratamento eficaz.

Pulpectomy in primary teeth consists of the complete removal of the irreversibly affected pulp or necrotic pulp tissue, chemical-mechanical preparation of the root dentin and filling root canals with a resorbable material, to keep the tooth as long as possible in the oral cavity, restoring function and health. There are several pulpectomy protocols described in the literature, however, there is no consensus among them and only few of them are open access. Therefore, there is a lack of clinical and practical guides to the practitioner in performing this procedure during pediatric dental care. The aim of this article is to present a clinically and radiographically successful pulpectomy protocol, based on scientific evidence, developed, and applied by the Research Group on Endodontics in Pediatric Dentistry at the Universidade Federal do Rio de Janeiro. This protocol includes indications, contraindications, operative techniques, materials, and guidelines for follow-up appointments. With this open access publication in Portuguese, we hope to disseminate an effective treatment and expand the outreach of a pulpectomy technique protocol to pediatric dentists and clinicians who treat children.

Resin infiltration for approximal caries lesions in primary and permanent teeth: case reports

Introduction: Minimally invasive dentistry aims to preserve the tooth structure and to achieve this, improved dental materials can be used. Among these, Icon®was developed for infiltration of non-cavitated enamel carious lesions or those located in the external third of dentin. Objective: To report two clinical cases in which Icon® was used to treat interproximal caries lesions in primary and permanent teeth. Case report: Two patients (10 and 13 years) attended the Pediatric Dental Clinic and the clinical and radiographic examination revealed non-cavitated enamel carious lesions and outer third of dentin on teeth 54 distal (D) and 55 mesial (M) (Patient 1), and teeth 24D and 25M (Patient 2), respectively. To restore the lesions, a resin infiltrant (Icon®) was used under rubber dam isolationand according to the manufacturer's recommendations. Results: The patients were assessed immediately after restoration, when complete sealing of the lesion was observed. Patient 1 returned for clinical and radiographic evaluation after 3 months and patient 2 returned after one month, where arrest of the carious lesions was detected. Conclusion: It is concluded that Icon® can be a good option of minimally invasive restorative material, with good applicability in Pediatric Dentistry.

Introdução: A odontologia minimamente invasiva visa maior preservação da estrutura dentária e novos materiais odontológicos vêm sendo utilizados para este fim. Dentre esses, o Icon® foi desenvolvido para infiltração de lesões de cárie não cavitadas localizadas em esmalte e/ou no terço externo de dentina. Objetivo: Relatar dois casos clínicos em que se utilizou o Icon® para tratamento de lesões de cárie interproximais em dentes decíduos e permanentes. Relato do caso: Dois pacientes (10 e 13 anos) compareceram à clínica de Odontopediatriada FO-UFRJ e ao exame clínico e radiográfico foram diagnosticadas lesões cariosas não cavitadas no terço externo de dentina e no esmalte dentário, nos dentes 54 distal (D) e 55 mesial (M) (Paciente 1) e dentes 24D e 25M (Paciente 2), respectivamente. Para restauração das lesões, foi utilizado o infiltrante de resina Icon® sob isolamento absoluto e de acordo com as recomendações do fabricante. Resultados: Os pacientes foram avaliados imediatamente após a restauração e observou-se um completo selamento da lesão. O paciente 1 retornou para avaliação clínica e radiográfica após 3 meses e o paciente 2 após 1 mês. Em ambos foi detectada paralisação da lesão cariosa. Conclusão: Conclui-se que o Icon® representa uma boa opção de material restaurador minimamente invasivo e com boa aplicabilidade em Odontopediatria.

Reliability of Two Methods of Evaluation of the Apical Limit of Obturation of Root Canals of Primary Teeth: A Pilot Study

Abstract Objective: To verify the concordance in the evaluation of the apical limit of obturation (ALO) in filled root canals of primary teeth between digital and visual methods. Material and Methods: Twenty periapical radiographs of endodontically treated primary teeth were digitalized and evaluated by an endodontics specialist (E1), a PhD pediatric dentist (E2), and a MSc general dentist (E3). Calibrated evaluators (Kappa = 1.00) analysed the images in a light-isolated environment two times (D1 and D2) with a one-week interval between evaluations. ALO scores were categorized as overfilled, flush-filled and underfilled. Results: The intra-rater reliability between methods was 0.82 (D1) and 0.75 (D2) for E1, 0.93 (D1 and D2) for E2, and 0.94 (D1 and D2) for E3. Inter-rater reliability ranged from 0.71 (E1 × E3) and 1.00 (E1 × E2) for the visual method to 0.76 (E1 × E3) and 0.88 (E1 × E2) for the digital method. Spearman correlation coefficients showed a similar ranking among the evaluators. There was greater disagreement among the underfilled and ideal scores. For all evaluators, the digital method favoured the identification of the ideal score. Conclusion: Both methods are suitable for the determination of the ALO of filled primary teeth and can be used in clinical practice.

Sealing Carious Fissures with Resin Infiltrant in Association with a Flowable Composite Reduces Immediate Microleakage?

Abstract Objective: To compare the immediate microleakage of carious fissures sealed with a caries infiltrant covered by a flowable composite or solely with a flowable composite. Material and Methods: Extracted carious molars (n=20) were selected and paired among the experimental groups according to caries progression scores. Experimental groups (n=10) were divided according to the following sealing techniques: 1) caries infiltrant (Icon) + flowable composite (Z350 flow); 2) flowable composite (Z350 flow). Specimens were immersed in 3% methylene blue and evaluated in a stereomicroscope. Microleakage scores were attributed independently by two calibrated evaluators and the mode value was considered as the mean for the specimen. Binomial tests were used to test differences between two independent sample proportions at 5% significance level. Results: In the flowable composite group, a higher prevalence of dye penetration along the full depth of the fissure was observed, compared with caries infiltrant + flowable composite (p<0.05). For specimens showing dye penetration up to half of the fissure, in caries infiltrant + flowable composite group, all specimens showed dye penetration into the sealant, but not over the infiltrant. Conclusion: Using caries infiltrant as sealing material under a flowable composite cover is effective to improve the immediate sealing ability in carious fissures compared to sealing with flowable composite.

Root canal segmentation in cone-beam computed tomography: comparison with a micro-CT gold standard

Aim: The purpose of this study was to compare root canal volumes (RCVs) obtained by means of cone beam computed tomography (CBCT) to those obtained by micro-computed tomography (micro-CT) after applying different segmentation algorithms. Methods: Eighteen extracted human teeth with sound root canals were individually scanned in CBCT and micro-CT using specific acquisition parameters. Two different images segmentation strategies were applied to both acquisition methods (a visual and an automatic threshold). From each segmented tooth, the root canal volume was obtained. A paired t-test was used to identify differences between mean values resulted from the experimental groups and the gold standard. In addition, Pearson correlation coefficients and the agreement among the experimental groups with the gold standard were also calculated. The significance level adopted was 5%. Results: No statistical differences between the segmentation methods (visual and automatic) were observed for micro-CT acquired images. However, significant differences for the two segmentation methods tested were seen when CBCT acquired images were compared with the micro-CT automatic segmentation methods used. In general, an overestimation of the values in the visual method were observed while an underestimation was observed with the automatic segmentation algorithm. Conclusion: Cone beam computed tomography images acquired with parameters used in the present study resulted in low agreement with root canal volumes obtained with a micro-CT tomography gold standard method of RCV calculation

Bulk-fill resins in pediatric dentistry: case reports with six-month follow-up

Introduction: Minimally invasive dental procedures are aimed at recovering function and aesthetics in a practical manner, providing excellent treatment options. Bulk-fill composites offer some benefits, such as placement in single increments up to 4-mm thickness, decreased polymerization shrinkage, and general reduction in clinical time, while keeping aesthetic properties similar to those of conventional composite resins. Objective: To report two clinical cases of class I restorations in permanent molars with dentin carious lesions (ICDAS 4) treated with bulk-fill composites using the occlusal stamp technique. Cases were followed up for 6 months and the restorations were evaluated according to the World Dental Federation (FDI) and Public Health Service (USPHS) criteria. Case report: Restorations were performed using the following materials: Case 1 ­ Filtek ™ bulk-fill flowable resin (3M ESPE) associated with Filtek Z350 XT resin (3M ESPE); Case 2 - Filtek bulk- ill packable resin (3M ESPE). Three blinded evaluators assessed the materials and techniques in the follow-up period. Results: Case 1 achieved the lowest scores by the FDI and USPHS criteria, presenting better aesthetic, functional, and biological properties. Conclusion: Both treatments were clinically satisfactory after 6 months. Bulk-fill composites are good materials, allowing for a fast, effective, and quality treatment for the pediatric patient.

Introdução: A evolução dos procedimentos operatórios minimamente invasivos possibilitou a recuperação da função e estética com praticidade, proporcionando tratamentos de excelência. Resinas bulk-fill apresentam vantagens: inserção em incrementos únicos de até quatro milímetros, menor contração de polimerização e redução do tempo clínico, mantendo propriedades estéticas semelhantes às resinas compostas convencionais. Objetivo : Relatar dois casos clínicos de restaurações classe I em lesão cariosa em dentina não cavitada (ICDAS 4), em molares permanentes, com resina bulk-fill utilizando a técnica da réplica oclusal. Adicionalmente, foi realizado o acompanhamento dos casos após seis meses, avaliando-se de acordo com os critérios World Dental Federation (FDI) e Public Health Service (USPHS). Relato : As restaurações foram realizadas utilizando-se os materiais: Caso 1: resina Filtek bulk-fill flow (3M ESPE) associada à resina de cobertura Filtek Z350 XT (3M ESPE); Caso 2: resina Filtek bulk-fill condensável (3M ESPE). Avaliações foram conduzidas por três avaliadores cegos em relação aos materiais e técnicas. Resultados : Caso 1 apresentou menores pontuações nos critérios FDI e USPHS, com melhores propriedades estéticas, funcionais e biológicas, comparado ao Caso 2. Conclusão : Ambos os tratamentos apresentaram resultados clínicos satisfatórios após 6 meses de avaliação. Resinas bulk- ill possibilitam um tratamento rápido, eficaz e de qualidade.

Accuracy of visual and image-based ICDAS criteria compared with a micro-CT gold standard for caries detection on occlusal surfaces

Abstract The aim of this study was to check the in vitro accuracy of ICDAS criteria on digital images compared to visual examination for the diagnosis of occlusal caries against a micro-CT gold standard. ICDAS was scored in 40 extracted permanent molars by means of visual inspection and stereomicroscopic images. Visual examinations were performed in duplicate and at a one-week interval by three different calibrated examiners. The analysis of digital images by ICDAS criteria was also performed in duplicate, 1 month after visual examinations. The detection methods were compared by means of sensitivity, specificity, area under the curve, predictive positive and negative values, and accuracy for two different thresholds (1- sound vs. carious teeth; 2- tooth requiring operative vs. non-operative treatment). Sensitivity and accuracy values for threshold 1 in the visual ICDAS and image-based ICDAS methods were high for sensitivity (0.93 and 0.97) and for accuracy (0.83 and 0.85), but low for specificity (0.55 for both methods). Specificity values for threshold 2 were 0.77 and 0.82, while sensitivity was 0.33 and 0.28 for each method. Spearman's rank correlation coefficient was 0.53 and 0.43 (p<0.05) for visual and image-based ICDAS compared to the gold standard scores. Both visual and image-based ICDAS scores were similar to each other in terms of diagnostic accuracy when compared to the micro-CT gold standard. Low specificity for the presence of caries and sensitivity for the detection of caries requiring operative treatment were found.

On the Causality Between Dentinal Defects and Root Canal Preparation: A Micro-CT Assessment

Abstract This study aimed to evaluate the cause-effect relationship between canal preparation with ProTaper Universal (PTU) system and dentinal defects formation using micro-computed tomography (micro-CT) analysis. Forty mesial canals of mandibular molars with a type II Vertucci's canal configuration were scanned at an isotropic resolution of 14.16 µm. The sample was assigned to an experimental (n = 30) and a control (n = 10) groups, and the mesial canals were prepared with PTU system up to F2 instrument. The specimens from the experimental group were scanned and the cross-section images of the mesial roots, before and after preparation, were screened to identify the presence of dentinal defects. In the control group, the specimens were sectioned perpendicularly to the long axis of the root into 1-mm-thick slices (n = 80) and examined under optical microscope. Once a dentinal defect was detected, the slice was scanned through micro-CT. In the experimental group, dentinal micro-cracks were observed in 4,828 slices (24.04%). In all cross-section images, dentinal defects identified in the postoperative images were already present in the corresponding preoperative image. In the control group, 13 out of 80 slices (16.25%) had at least one dentinal defect visualized under stereomicroscopy, which was identified after a further micro-CT scanning. Micro-CT showed reliability as similar as optical microscopy in detecting dentinal defects, adding the possibility of tracking the dentinal tissue, before and after canal preparation, and providing a clear visualization of micro-cracks. Root canal preparation with PTU system did not induce the formation of new dentinal defects.

Resumo O objetivo deste estudo foi avaliar a relação de causa-efeito entre o preparo do canal radicular com o sistema ProTaper Universal (PTU) e a formação de defeitos dentinários usando a análise por micro-tomografia computadorizada (micro-CT). Quarenta raízes mesiais de molares inferiores com a configuração tipo II de Vertucci foram escaneadas com resolução isotrópica de 14.16 μm. A amostra foi distribuída em um grupo experimental (n = 30) e um grupo controle (n = 10), e os canais mesiais foram preparados com o sistema PTU até a lima F2. As amostras do grupo experimental foram escaneadas e as imagens de secção transversal das raízes mesiais, antes e após o preparo, foram analisadas ​​para identificar a presença de defeitos dentinários. No grupo controle, os dentes foram seccionados perpendicularmente em relação ao longo eixo da raiz em fatias de 1 mm de espessura (n = 80) e examinados ao microscópio óptico. Uma vez detectado um defeito dentinário, a fatia foi escaneada através da micro-CT. No grupo experimental, defeitos dentinários foram observados em 4.828 secções transversais (24,04%). Em todas as imagens de secção transversal, os defeitos dentinários após os procedimentos experimentais já estavam presentes na secção pré-operatória correspondente. No grupo controle, 13 das 80 fatias (16,25%) apresentaram pelo menos um defeito dentinário visualizado através do microscópio, o qual foi identificado em um escaneamento posterior. A micro-CT mostrou confiabilidade com a microscopia óptica para detecção e visualização dos defeitos dentinários, permitindo acompanhar o tecido dentinário antes e depois do preparo do canal. O preparo do canal radicular com o sistema PTU não induziu a formação de novos defeitos dentinários.

Quantitative transportation assessment in simulated curved canals after large apical preparations

Aim: To evaluate the ability of rotary (ProTaper Universal [PTU] and ProTaper Next [PTN]), reciprocating (Reciproc [R] and WaveOne [WO]) and adaptive (Twisted File Adaptive [TFA]) systems in maintaining the original canal profile in straight and curved parts after apical preparations up to size 40. Methods: Resin blocks with simulated curved canals were randomly assigned to five groups: PTU, PTN, R, WO and TFA. Images were captured from each block before and after canal preparation (n=10). Assessment of canal transportation was obtained for the straight and curved parts of the canal. ANOVA followed by Tukey's test was used (α = 5%). Results: Transportation values were increased at the curved part (P = .00). For both canal levels, TFA system induced the lowest mean of canal transportation followed by PTN, R, WO and PTU systems. At the straight portion, transportation for R and TFA systems were similar (P > .05), and these values were significantly lower than for WO, PTN and PTU (P = .00). At the curved portion, TFA resulted in less canal transportation, followed by PTN, R, WO and PTU systems (P = .00). Conclusions: TFA system produced less canal transportation than other systems tested during large apical preparations. (AU)

Quantitative transportation assessment in curved canals prepared with an off-centered rectangular design system

Abstract The purpose of this study was to assess the ability of an off-centered rectangular design system [ProTaper Next (PTN)] to maintain the original profile of the root canal anatomy. To this end, ProTaper Universal (PTU), Reciproc (R) and WaveOne (WO) systems were used as reference techniques for comparison. Forty clear resin blocks with simulated curved root canals were randomly assigned to 4 groups (n = 10) according to the instrumentation system used: PTN, PTU, R and WO. Color stereomicroscopic images of each block were taken before and after instrumentation. All image processing and data analysis were performed with an open source program (Fiji v.1.47n). Evaluation of canal transportation was obtained for two independent regions: straight and curved portions. Univariate analysis of variance and Tukey's Honestly Significant Difference test were performed, and a cut-off for significance was set at α = 5%. Instrumentation systems significantly influenced canal transportation (p = 0.000). Overall, R induced significantly lower canal transportation compared with WO, PTN and PTU (p = 0.000). The curved portion displayed superior canal transportation compared to the straight one (p = 0.000). The significance of the difference among instrumentation systems varied according to the canal level evaluated (p = 0.000). In its straight portion, R and WO exhibited significantly lower transportation than PTN; whereas in the curved portion, R produced the lowest deviation. PTU exhibited the highest canal transportation at both levels. It can be concluded that PTN produced less canal transportation than PTU and WO; however, R exhibited better centering ability than PTN.

Three-dimensional Quantitative Porosity Characterization of Syringe- versus Hand-mixed Set Epoxy Resin Root Canal Sealer

The aim of the present study was to compare the porosity characteristics of AH Plus Jet(tm) syringe-mix and the conventional hand-mixed AH Plus root canal sealers by three-dimensional quantitative high-resolution micro-computed tomography (micro-CT). Seven test specimens were prepared from each tested sealer by a single operator following the manufacturer's instructions and poured into pre-lubricated plastic split-ring moulds. Set sealer test specimens were scanned using a micro-CT device and the shadow images were reconstructed into cross-sectional slices. The evaluated parameters were (i) total pore count, (ii) total pore volume and mean pore volume, (iii) total porosity (% of pore volume in relation to total sealer volume) and (iv) mean pore distance to the sealer lateral external surface. In both groups, most pores were localized within the external sealer perimeter (0.05 mm from the external surface). Hand-mixed AH Plus specimens showed statistically significant higher mean total pore count, total pore volume and total porosity (p=0.001) than the syringe-mixed specimens. However, mean pore sizes in AH Plus syringe-mixed specimens were significantly higher (p=0.046) than the AH Plus hand-mixed counterparts. Hand-mixed AH Plus was associated with higher total mean pore count, volume and total porosity compared to syringe mixed AH Plus.

Resumo O objetivo do presente estudo foi comparar a porosidade do AH Plus Jet(tm) dotado de misturador automático com o AH Plus convencional manipulado a mão a partir de um método quantitativo de microtomografia computadorizada (micro-CT). Para cada cimento, sete espécimes foram preparados por um único operador, seguindo as instruções do fabricante, e inseridas em anéis de plástico. Após o tempo de presa, os cimentos foram escaneados utilizando o micro-CT e as imagens foram reconstruídas. Os parâmetros avaliados foram (i) contagem total de poros, (ii) volume total de poros e média dos volumes dos poros, (iii) porosidade total (% de volume de poros em relação ao volume total do cimento) e (iv) distância média dos poros em relação ao perímetro externo (0,05 mm da superfície externa). O AH Plus manipulado a mão apresentou maior número de poros, maior volume total de poros e porosidade total (p=0,001) comparado com o AH Plus com misturador. No entanto, a média de tamanho dos poros foi estatisticamente superior no AH Plus com misturador quando comparado com o AH Plus manipulado a mão (p=0,046). O AH Plus manipulado a mão foi associado com uma maior média de poros, volume e porosidade quando comparado com o AH Plus com misturador.

Micro-CT Evaluation of Non-instrumented Canal Areas with Different Enlargements Performed by NiTi Systems

The aim of this study was to compare the percentage of non-instrumented area of root canals prepared with different enlargements using single-file reciprocating systems (Reciproc and WaveOne) and a conventional multi-file rotary (BioRaCe) system by micro-computed tomographic analysis. Thirty mesial roots of mandibular molars with moderate curvature (10° to 20°) presenting a type II Vertucci canal configuration and similar internal volume were chosen and scanned at an isotropic resolution of 14.16 µm. The sample was assigned to 3 groups (n=10) according to the system used for root canal preparation: Reciproc, WaveOne, and BioRaCe groups. Second and third scans were taken after the canals were prepared with instruments sizes 25 and 40, respectively. The recorded images of the surface area voxels of the canals, before and after preparation were examined from the furcation level to the apex to quantify the non-instrumented surface. Statistical data were compared using GLM for repeated-measures with a significance level set at 5%. Instrumentation systems did not influence the percentage of untouched root canal surfaces (p=0.690) whilst a significant reduction in the percentage of static voxels was observed after the enlargement of the root canal (p=0.010) in all groups (p=0.507). None of the systems was able to prepare the entire surface area of the mesial root canal of mandibular molars. The increased final apical size resulted in a significant positive effect on the shaping ability of the tested systems.

Resumo O objetivo deste estudo foi comparar a porcentagem de área não-instrumentada de canais radiculares preparados com diferentes ampliações utilizando sistemas reciprocantes de lima única (Reciproc e WaveOne) e um sistema rotatório convencional de múltiplas limas (BioRaCe) usando a análise da micro tomografia computadorizada. Trinta raízes mesiais de molares inferiores com curvatura moderada (10º a 20º) apresentando a configuração classe II de Vertucci e semelhança de volume do canal foram selecionadas e escaneadas em uma resolução isotrópica de 14,16 µm. A amostra foi dividida em 3 grupos (n=10) de acordo com o sistema utilizado para a preparação do canal radicular: grupo Reciproc, grupo WaveOne e grupo BioRaCe. Segundo e terceiro escaneamentos foram realizados após os canais serem preparados com instrumentos tamanhos 25 e 40, respectivamente. As imagens registradas de voxels da área de superfície dos canais, antes e após o preparo, foram examinadas desde o nível da furca até o ápice para quantificar a superfície não instrumentada. Os dados foram comparados estatisticamente através de GLM para medidas repetidas com um nível de significância de 5%. Os sistemas de instrumentação não influenciaram o percentual de superfícies não tocadas dos canais radiculares (p=0,690), enquanto que uma redução significativa no percentual de voxels estáticos foi observada após o alargamento do canal radicular (p=0,010) em todos os grupos (p=0,507). Nenhum dos sistemas foi capaz de preparar toda a área de superfície do canal mesial dos molares inferiores. O aumento do tamanho final apical resultou num efeito positivo significativo sobre a capacidade de modelar dos sistemas testados.

Postoperative Pain after Foraminal Instrumentation with a Reciprocating System and Different Irrigating Solutions

The aim of the present study was to evaluate and compare postoperative pain after foraminal instrumentation using 5.25% sodium hypochlorite (NaOCl) or 2% chlorhexidine (CHX) gel irrigation protocol in nonvital single-rooted teeth after reciprocating instrumentation. Sixty-two volunteers presenting a single root canal diagnosed with asymptomatic necrosis and apical periodontitis were randomized into 2 experimental groups regarding the irrigation protocol (ie, 5.25% NaOCl and 2% CHX gel groups). Endodontic treatment was performed in a single session under reciprocating instrumentation with foraminal instrumentation. Volunteers were instructed to record pain intensity. Scores from 1 to 4 were attributed to each kind of pain after 24, 48, and 72 h. Kolmogorov-Smirnov and Student´s t tests were used to determine significant differences at p<0.05. On average, the percentage of patients that had no or mild pain after 24, 48 or 72 h was 77.4%, 88.7% and 95.1%, respectively. No statistically significant age difference was found between the groups (p>0.05, Student´s t test). Postoperative pain showed no statistically significant difference at any observation period when using 5.25% NaOCl or 2% CHX gel (p>0.05). Moreover, no significant difference was observed in the mean number of analgesic tablets used between the groups (p>0.05). In conclusion, the use of 5.25% NaOCl or 2% CHX gel resulted in the same postoperative pain. Therefore, it can be inferred that irrigant choice has no relation with short-term follow up regarding postoperative pain.

O objetivo do presente estudo foi avaliar e comparar a dor pós-operatória após a instrumentação foraminal usando NaOCl 5,25% ou gel de CHX 2% em dentes não vitais unirradiculares após instrumentação reciprocante. Sessenta e dois voluntários, apresentando um único canal radicular diagnosticado com necrose assintomática e periodontite apical, foram randomizados em dois grupos experimentais de acordo com o protocolo de irrigação (ou seja, grupos de NaOCl 5,25% e CHX gel 2%). O tratamento endodôntico foi realizado em uma única visita sob instrumentação reciprocante com instrumentação foraminal. Os voluntários foram instruídos a registrar a intensidade da dor. Escores de 1-4 foram atribuídos a cada tipo de dor após 24, 48 e 72 h. Testes de Kolmogorov-Smirnov e t de Student foram utilizados para determinar diferenças significativas em p<0,05. Em média, o percentual de pacientes que teve nenhumaou leve dor após 24, 48 ou 72 h foi de 77.4%, 88.7% e 95.1%, respectivamente. Não foi encontrada diferença de idade estatisticamente significante entre os grupos (p>0,05, teste t de Student). A dor pós-operatória não apresentou diferença estatisticamente significativa em qualquer período de observação ao usar NaOCl 5,25% ou CHX gel 2% (p>0,05). Além disso, não foi observada diferença significativa no número médio de comprimidos analgésicos utilizados entre os grupos (p>0,05). O uso de NaOCl 5,25% ou CHX gel 2% resultou na mesma dor pós-operatória. Portanto, pode-se inferir que a escolha do irrigante não tem relação com um acompanhamento a curto prazo em relação a dor pós-operatória.

Evaluation of foraminal transportation during foraminal enlargement with different instrumentation systems

Aim: To evaluate the foraminal transportation during foraminal enlargement after manual instrumentation with stainless steel files, preparation with the Mtwo system and Reciproc R25 file. Methods: Thirty roots were selected, divided in three groups and prepared in accordance with the different instrumentation systems: Hand Files (HF); Mtwo system (MS); and Reciproc system (RS). All groups were prepared with the instrumentation level 1 mm beyond the apex. Photomicrographs were performed using scanning electron microscopy, to record the foraminal anatomy before and after instrumentation. Data were analyzed using ANOVA followed by Tukey's test with a significance level of 5%. Results: The group instrumented with hand files showed higher foraminal transportation when compared to the Mtwo and Reciproc groups (p<0.05). Reciproc group showed lower transportation when compared to the Mtwo group (p<0.05). Conclusions: The stainless steel files caused significant foraminal transportation, while Reciproc system showed safe apical preparation, with little transportation.