A microscopia eletrônica de varredura pode ser usada para medir quantitativamente a rugosidade da dentina? / Can Scanning Electron Microscopy be used to quantitatively measure dentine roughness?

Objective: The aim of this study was to determine if SEM used with imaging software could be used to quantitatively determine the extent of dentine roughness due to tooth-brushing. Material and methods: Flat, polished dentine surfaces were subjected to 25,000 cycles of simulated tooth-brushing at 2 strokes per second with a load of 200 g. At the end of the brushing cycle, dentine surfaces were first assessed using profilometry and then subjected to SEM analysis. Ra (average roughness) readings were obtained for profilometric assessment. Using imaging software, the horizontal distance between adjacent characteristic grooves noted on micrographs was measured, ensuring that the middle of each crest of the associated groove was used as the reference point, the Crest-to-Crest distance (C-C distance). These two parameters were examined statistically for correlation. Results: When Spearman Rank tests were utilized the correlation between average Ra and crest to crest measurements was 0.709 (p <0.01). The Bland Altman plot, however, showed poor agreement between the two test parameters. Conclusion: Further work is needed to validate the use of this methodology in the quantitative assessment of tooth surface loss due to abrasion (AU)

Objetivo: O objetivo deste estudo foi determinar se o MEV usado com software de imagem poderia ser usado para determinar quantitativamente a extensão da rugosidade da dentina devido à escovação dentária. Material e Métodos: Superfícies dentinárias planas e polidas foram submetidas a 25.000 ciclos de escovação dentária simulada a 2 movimentos por segundo com uma carga de 200g. No final do ciclo de escovação, as superfícies dentinárias foram primeiro avaliadas por perfilometria e depois submetidas à análise MEV. Leituras de Ra (rugosidade média) foram obtidas para avaliação perfilométrica. Utilizando um software de imagem, foi medida a distância horizontal entre sulcos característicos adjacentes observados nas micrografias, garantindo que o meio de cada crista do sulco associado fosse usado como ponto de referência, a distância crista a crista (distância CC). Esses dois parâmetros foram examinados estatisticamente para correlação. Resultados: Quando foram utilizados os testes de Spearman Rank, a correlação entre a média de Ra e as medidas de crista a crista foi de 0,709 (p<0,01). O gráfico de Bland Altman, no entanto, mostrou fraca concordância entre os dois parâmetros de teste. Conclusão: Mais trabalhos são necessários para validar o uso desta metodologia na avaliação quantitativa da perda da superfície dentária devido à abrasão(AU)

Color and surface roughness alterations of bulk-fill resin composites submitted to simulated toothbrushing with whitening dentifrices

Aim: To evaluate the surface roughness and color stability of bulk-fill resin composites after simulated toothbrushing with whitening dentifrices. The radioactive/relative dentin abrasion (RDA) and radioactive/relative enamel abrasion (REA) of dentifrices were also assessed. Methods: Specimens (n=10) of Tetric N Ceram Bulk Fill (TNCB), Filtek One Bulk Fill (FOB) resin composites, and Z100(Control) were prepared using a cylindrical Teflon matrix. Surface roughness (Ra, µm) was assessed by a roughness meter and the color evaluations (ΔEab , ΔE00 , WID ) were performed using a digital spectrophotometer based on the CIELAB system. Three measurements were performed per sample, before and after simulated toothbrushing with 3D Oral-B White Perfection (3DW) and Black is White (BW) dentifrices. The abrasivity (REA and RDA values) of the used dentifrices was also determined by the Hefferren abrasivity test. Results: The Ra values increased significantly in all resin composites after 3DW and BW toothbrushing. The acceptable threshold color varied among resin composites, and TNCB and Z100 presented the highest ΔEab and ΔE00 for BW dentifrice. The 3DW dentifrice was significantly more abrasive than BW dentifrice on enamel and dentin. Conclusions: simulated toothbrushing with tested whitening dentifrices increased the surface roughness at acceptable levels. The Tetric N Ceram Bulk-fill and Z100 composite showed the highest color alteration in BW. 3D White Perfection dentifrice was more abrasive on dentin and enamel than Black is White.

Qualitative Characterization of the Abrasive Component of Charcoal-Containing Toothpastes and the Effect on Dentin Roughness / Caracterización Cualitativa del Componente Abrasivo de las Pastas Dentales que Contienen Carbón Vegetal y la Rugosidad de la Dentina

This study investigated the effect of commercially available whitening toothpastes containing charcoal on dentin. Nine charcoal-containing toothpastes were compared with 3 whitening toothpastes (positive control) and distilled water (negative control). Periodontally hopeless molars were cleaned and washed and the occlusal table removed to expose dentin. The teeth were mounted in auto-polymerizing resin and exposed dentine surfaces polished with water-cooled decreasing grits of silica carbide paper up to 1500 grit. Baseline average roughness (Ra) measurements were taken. Specimens were then mounted in an automatic tooth-brushing machine and brushed for 5000 cycles. Repeat Ra measurements were taken. Specimens were brushed in 5000-cycle increments up to 25,000 cycles with Ra measurements being taken at each time point. Between abrasive challenges specimens were stored in distilled water. All toothpaste samples were sputter coated and examined under a scanning electron microscope to qualify the shape and size of the abrasive components of the formulations. Data were analyzed using a two-way analysis of variance with post hoc Bonferroni. The results demonstrated that the abrasive effect, in terms of increasing Ra, on dentin was noted as early as 5000 cycles for all the tested toothpastes (p<0.05). The effect of continued brushing showed an overall cumulative effect on dentine roughness up to 25000 cycles. When toothpastes were compared between groups at each time-point, dentin specimens brushed with Pursito were statistically similar to the control group. At 25,000 cycles all dentin samples were significantly rougher compared to Pursito and the control groups. It may be concluded that all the tested toothpastes have an abrasive effect on dentin surfaces.

Este estudio investigó el efecto sobre la dentina de las pastas dentales blanqueadoras disponibles en el mercado que contienen carbón vegetal. Se compararon nueve dentífricos que contenían carbón vegetal con 3 dentífricos blanqueadores (control positivo) y agua destilada (control negativo). Los molares sin material periodontal se limpiaron y lavaron y se retiró la tabla oclusal para exponer la dentina. Los dientes se montaron en resina autopolimerizable y las superficies expuestas de la dentina se pulieron con papel de carburo de sílice de grano decreciente enfriado con agua hasta grano 1500. Se tomaron medidas de rugosidad promedio (Ra) de referencia. Luego, las muestras se montaron en una máquina automática de cepillado de dientes y se cepillaron durante 5000 ciclos. Se tomaron medidas repetidas de Ra. Las muestras se cepillaron en incrementos de 5000 ciclos hasta 25 000 ciclos y se tomaron medidas de Ra en cada punto de tiempo. Entre periodos abrasivos, las muestras se almacenaron en agua destilada. Todas las muestras de pasta de dientes se recubrieron por pulverización catódica y se examinaron bajo un microscopio electrónico de barrido para calificar la forma y el tamaño de los componentes abrasivos de las formulaciones. Los datos se analizaron utilizando un análisis de varianza de dos vías de Bonferroni post hoc. Los resultados demostraron que el efecto abrasivo, en términos de aumento de Ra, sobre la dentina se notó ya en 5000 ciclos para todas las pastas dentales probadas (p<0,05). El efecto del cepillado continuo mostró un efecto acumulativo general sobre la rugosidad de la dentina hasta 25.000 ciclos. Cuando se compararon las pastas dentales entre los grupos en cada momento, las muestras de dentina cepilladas con Pursito fueron estadísticamente similares al grupo de control. A los 25.000 ciclos, todas las muestras de dentina eran significativamente más ásperas en comparación con Pursito y los grupos controles. Se puede concluir que todas las pastas dentales probadas tienen un efecto abrasivo sobre las superficies dentinarias.

Bond strength of composite resin/universal adhesive to dentin submitted to radiotherapy / Fuerza de unión de resina compuesta/adhesivo universal a dentina sometida a radioterapia

Aim: To evaluate the bond strength of a universal adhesive system to dentin submitted to radiotherapy. Materials and Methods: Sixty extracted human teeth were divided into two groups (n = 30): without radiotherapy (control); with radiotherapy, according to the adhesive protocol (n=15): ER-etch-and-rinse (acid + Single Bond Uni-versal); SE-self-etch (Single Bond Universal). The analyzes were shear bond strength (SBS) (n=10), failure pattern (n=10) and scanning electron microscopy (n=5). Data was analyzed by a two-way ANOVA (α =0.05). Results: The radiotherapy decreased SBS of the restorative material to dentin (p<0.0001). The ER protocol provided lower bond strength values (p<0.001). The predominant type of fracture without radiotherapy was mixed (SE), cohesive to the material (ER). Both protocols presented adhesive failures with radiotherapy. Teeth had a hybrid layer and long resin tags (without radiotherapy) and few tags (with radiotherapy). Conclusions: The SE adhesive mode favors the shear bond strength of resin to dentin in teeth submitted to radiotherapy.

Objetivo: Evaluar la fuerza de adhesión de un sistema adhesivo universal a la dentina sometida a radioterapia. Materiales y Métodos: Sesenta dientes humanos extraídos se dividieron en dos grupos (n = 30): sin radioterapia (control); con radioterapia, según protocolo adhesivo (n=15): ER-grabado y enjuague (ácido + Single Bond Universal); autograbado SE (Single Bond Universal). Los análisis ejecutados fueron resistencia al cizallamiento (SBS) (n=10), patrón de falla (n=10) y microscopía electrónica de barrido (n=5). Los datos se sometieron al test de ANOVA de dos vías (α =0,05). Resultados: La radioterapia disminuyó la SBS del material restaurador a la dentina (p<0,0001). El protocolo ER proporcionó valores de fuerza de unión más bajos (p<0,001). El tipo de fractura predominante sin radioterapia fue mixta (SE), cohesiva al material (ER). Ambos protocolos presentaron fallas adhesivas con radioterapia. Los dientes tenían una capa híbrida y colas de resina largas (sin radioterapia) o pocas colas de resina (con radioterapia). Conclusión: El modo adhesivo SE favorece la resistencia al corte de la resina a la dentina en dientes sometidos a radioterapia.

Clinical implementation of comprehending dentin on a microscopic level

SUMMARY: The aim of the present in vitro study is to visualize dentin to get an in-depth knowledge of the nature of dentin that could provide useful information regarding conditioning dentinal substrate when treating dentinal lesions. Forty-nine extracted human third molars were obtained and prepared to produce artificial dentinal lesions through demineralizing with acetic acid for 7 and 14 days, or lactic acid for 7 days. The teeth were divided into groups and treated with either NaOCl, pepsin, trypsin, or phosphoric acid. To obtain information on the morphology of the treated dentinal surfaces, all samples were visualized under high resolution field emission scanning electron microscope. With high magnification reaching x50000 dentin was clearly visualized together with its constitutes. The effect of various demineralization approaches and various treatment protocols were demonstrated clearly. The relationship between the conditioning procedure steps and the subsequent bond strength was discussed. To our best knowledge, there is no previous clear highly magnified scanning electron microscope images for dentin, and dentinal components and constitutes with and without various treatments. The current in vitro study suggests the complexity nature of dentin as a substrate that should be treated carefully especially with technique sensitive procedures such as adhesive restorations.

El objetivo del presente estudio in vitro fue visualizar la dentina para obtener un conocimiento completo de la naturaleza de ella lo que podría proporcionar información útil sobre el acondicionamiento del sustrato dentinario en el tratamiento de lesiones dentinarias. Se obtuvieron 49 terceros molares humanos extraídos y se prepararon para producir lesiones dentinales artificiales mediante desmineralización con ácido acético por 7 y 14 días, o ácido láctico por 7 días. Los dientes se dividieron en grupos y se trataron con NaOCl, pepsina, tripsina o ácido fosfórico. Para obtener información sobre la morfología de las superficies dentinarias tratadas, todas las muestras se visualizaron bajo un microscopio electrónico de barrido de emisión de campo de alta resolución. Con un gran aumento que alcanzó x50000, la dentina se visualizó claramente junto con sus componentes. Se demostró el efecto de varios enfoques de desmineralización y varios protocolos de tratamiento. Se discutió la relación entre los pasos del procedimiento de acondicionamiento y la subsiguiente fuerza de unión. Hasta donde sabemos, no hay imágenes claras previas de microscopio electrónico de barrido altamente ampliadas para la dentina y los componentes y constituyentes de la dentina con y sin diferentes tratamientos. El estudio in vitro actual sugiere la naturaleza compleja de la dentina como sustrato que debe tratarse con cuidado, especialmente en los procedimientos sensibles a la técnica, tal como las restauraciones adhesivas.

Efecto de diferentes condiciones y modos de aplicación sobre la fuerza de unión de los adhesivos a la dentinaEffect of different conditions and modes of application on bond strength of adhesives to dentine / Effect of different conditions and modes of application on bond strength of adhesives to dentine

Objective: To evaluate the microtensile bond strength in different dentine conditions (etched-E, non-etched-N, dry-D and wet-W) of a multimode adhesive (Scotchbond Universal-SU, 3M/ESPE) and a total etching adhesive (Ambar-AB, FGM) using a sonic device (Smart Sonic Device-SD, FGM). Material and methods: In this in vitro study, ninety six sound extracted human molars were divided into 12 groups (n=8) according to different dentine conditions and adhesive systems. Enamel was removed and the middle dentine surfaces were polished. Each adhesive system was applied according to the different dentine conditions, and composite resin blocks were incrementally built up and stored for 24 hours. Specimens were sectioned into sticks and bond strength data were analyzed with the Kruskal-Wallis test and Mann-Whitney U tests. Results: No effects of sonic application and were observed. In general, AB showed lower results compared to the SU. E and N conditions did not statistically affect the bond strength of SU groups. Dry dentine presented statistically superior bond strength values when compared to wet dentine for SU/E/SD group. Conclusion: Adhesion of dry dentine with multimode adhesive system may be superior to wet dentine with sonic application. The modes of application had no influence in bond strength of studied adhesives.

Objetivo: Evaluar la resistencia de la unión microtensil en diferentes condiciones de dentina (grabado-E, sin grabado-N, seco-D y húmedo-W) de un adhesivo multimodo (Scotchbond Universal-SU, 3M/ESPE) y un adhesivo de grabado total (Ambar-AB, FGM) utilizando un dispositivo sónico (Smart Sonic Device-SD, FGM). Material y Métodos: En este estudio in vitro, noventa y seis molares humanos extraídos sanos se dividieron en 12 grupos (n=8) de acuerdo con diferentes condiciones de dentina y sistemas adhesivos. Se eliminó el esmalte y se pulieron las superficies centrales de la dentina. Cada sistema adhesivo se aplicó de acuerdo con las diferentes condiciones de dentina, y los bloques de resina compuesta se acumularon de forma incremental y se almacenaron durante 24h. Las muestras se seccionaron en barras y los datos de resistencia de la unión se analizaron con la prueba de Kruskal-Wallis y la prueba de U de Mann-Whitney. Resultado: No se observaron efectos de la aplicación sónica. En general, AB mostró resultados más bajos en comparación con el SU. Las condiciones E y N no afectaron estadísticamente la fuerza de unión de los grupos SU. La dentina seca presentó valores de fuerza de adhesión estadísticamente superiores en comparación con la dentina húmeda para el grupo SU/E/SD. Conclusión: La adhesión de la dentina seca con un sistema adhesivo multimodo puede ser superior a la dentina húmeda con aplicación sónica. Los modos de aplicación no tuvieron influencia en la resistencia de la unión de los adhesivos estudiados.

Oral Healthcare Services Delivered During COVID-19 Lockdown: A Report from Eastern Mediterranean Region

ABSTRACT Objective: To describe oral healthcare services administered during the lockdown in the Eastern Mediterranean region and to investigate the role of socio-professional characteristics of dental practitioners or their self-reported COVID-19 infection. Material and Methods: A questionnaire was distributed to dental practitioners in all healthcare sectors in Jordan, Egypt, and Saudi Arabia. Results: There was a total of 335 participants, with the majority being females (N=225, 67.2%) and general practitioners (N=202, 60.3%). Cellulitis was the most common emergency encountered (N=108). The most common urgent procedures were for pulpitis, abscesses, and pericoronitis (N=191, 130, and 95, respectively). Country-specific significant associations were pulpitis in Egypt and Jordan, broken symptomatic teeth in Jordan, and biopsy in Egypt (p<0.05). The Ministry of Health was significantly associated with the management of dental infections, avulsion, and orthodontic emergencies, while university hospitals were significantly associated with advanced restorative procedures (p<0.05). Male practitioners performed significantly more procedures, particularly surgical emergencies (p<0.05). Conclusion: Dental infections were the most common complaints among dental patients during lockdown. Countryand sector-specific dental procedures are detected. Male gender seems to play a determinant role in performing a higher number of procedures, particularly for surgical emergencies (AU).

Do irrigation solutions used during root canal instrumentation influence the adhesion of glass fiber posts? A systematic review / As soluções de irrigação usadas durante a instrumentação do canal radicular influenciam a adesão de pinos de fibra de vidro? Uma revisão sistemática

Statement of problem: the bond strength between adhesive cement and root dentin can be affected by irrigation protocols. Purpose: therefore, the objective of this systematic review was to answer the following question: Do irrigation solutions used during root canal instrumentation influence the adhesion of glass fiber posts to root dentin? Material and Methods: this study followed the recommendations of PRISMA 2020 for writing. PubMed, Scopus, Web of Science, and LILACS databases were searched for articles published until 26 January, 2022. Grey literature and a manual search were also performed. The inclusion criteria were based on the PICO strategy: permanent human or animal teeth (P), which were irrigated during root canal instrumentation with endodontic substances (I) and compared to irrigation with sodium hypochlorite at various concentrations (C) to analyze the bond strength of glass fiber posts (O). Two authors independently performed data extraction and the risk of bias. Results: eight articles were included. Four articles were classified as having a high risk of bias, where the others as medium risk. Studies have reported conflicting results regarding the influence of irrigating solutions and the different concentrations of sodium hypochlorite on the adhesion of glass fiber posts to root dentin. Conclusion: the heterogeneity between studies did not allow the conclusion of a true estimate regarding this topic, and further well-designed studies are needed to clarify this issue. Register: CRD42020221835. (AU)

Definição do problema: a resistência de união entre o cimento adesivo e a dentina radicular pode ser afetada pelos protocolos de irrigação. Objetivo: portanto, o objetivo desta revisão sistemática foi responder à seguinte questão: As soluções de irrigação usadas durante a instrumentação do canal radicular influenciam a adesão de pinos de fibra de vidro à dentina radicular? Material e Métodos: este estudo seguiu as recomendações do PRISMA 2020 para sua redação. As bases de dados PubMed, Scopus, Web of Science e LILACS foram pesquisadas para artigos publicados até 26 de janeiro de 2022. A literatura cinza e uma pesquisa manual também foram realizadas. Os critérios de inclusão foram baseados na estratégia PICO: dentes humanos ou animais permanentes (P), que foram irrigados durante a instrumentação do canal radicular com substâncias endodônticas (I) e comparados à irrigação com hipoclorito de sódio em várias concentrações (C) para analisar a resistência de união de pinos de fibra de vidro (O). Dois autores realizaram independentemente a extração de dados e o risco de viés. Resultados:oito artigos foram incluídos. Quatro artigos foram classificados como de alto riscode viés, enquanto os demais como de médio risco. Estudos relataram resultados conflitantes sobre a influência de soluções irrigadoras e as diferentes concentrações de hipoclorito de sódio na adesão de pinos de fibra de vidro à dentina radicular. Conclusão: a heterogeneidade entre os estudos não permitiu a conclusão de uma estimativa verdadeira sobre este tópico, sendo necessários mais estudos bem delineados para esclarecer esta questão. Registo: CRD42020221835 (AU)

Análise de metodologias para avaliação da solubilidade do cimento à base de silicato de cálcio Bio-C Sealer / Analysis of methodologies for evaluating the solubility of calcium silicate-based sealer Bio-C Sealer

Introdução: Cimentos endodônticos à base de silicato de cálcio demonstram maior solubilidade em água destilada. Emprego de metodologias alternativas pode auxiliar em melhor compreensão sobre a solubilidade desses materiais. Objetivo: Avaliar o efeito da solução de imersão e do tipo de modelo experimental na solubilidade de cimento pronto para uso Bio-C Sealer. Material e método: Modelos circulares de polietileno ou dentina bovina (n = 16) foram confeccionados. Após inserção do cimento, os espécimes foram mantidos em estufa a 37 °C por 48 horas. Posteriormente, as amostras foram pesadas em balança de precisão para determinação da massa inicial. Na sequência, os espécimes foram imersos em 7,5 mL de água destilada (pH 6,5) ou PBS (pH 7,0) (n = 8) por 28 dias. Após isso, as amostras foram removidas das soluções e pesadas a cada 24 horas até a estabilização da massa final (0,001g). Corpos de prova confeccionados com Bio-C Sealer foram empregados como controle. A solubilidade foi avaliada de acordo com a diferença entre a massa inicial e final em porcentagem. Teste ANOVA Two-Way e teste post-hoc de Tukey foram realizados (α = 0,05). Resultado: Imersão em água destilada proporcionou maior solubilidade em comparação com PBS, independentemente do modelo experimental (p < 0,05). Corpos de prova apresentaram maior solubilidade, seguidos dos modelos de polietileno e dentina imersos em água destilada (p < 0,05). Não houve diferença entre os modelos experimentais imersos em PBS (p > 0,05). Conclusão: Bio-C Sealer apresenta solubilidade significativamente maior em água destilada do que em PBS em todas condições. Modelo experimental empregando dentina bovina e PBS como solução de imersão demonstra diminuir a perda de massa de Bio-C Sealer e pode ser uma alternativa valiosa para avaliar a solubilidade de cimentos biocerâmicos

Introduction: Calcium silicate-based sealers demonstrate greater solubility in distilled water. The use of alternative methodologies can help at better understanding the solubility of these materials. Objective: To evaluate the effect of the immersion solution and the type of experimental model on the solubility of readyto-use Bio-C Sealer. Material and method: Circular models of polyethylene or bovine dentin (n = 16) were made. After insertion of the sealer, the specimens were kept in an oven at 37°C and 95% humidity for 48h. Subsequently, the samples were weighed on a precision balance to determine the initial mass. Next, the specimens were immersed in 7.5 mL of distilled water (pH 6.5) or PBS (pH 7.0) (n = 8) for 28 days. After that, the samples were removed from the solutions and weighed every 24 hours until the final mass stabilized (0.001g). Test specimens made with Bio-C Sealer were used as a control. Solubility was evaluated according to the difference between the initial and final mass in percentage. Two-Way ANOVA test and Tukey post-hoc tests were performed (α=0.05). Result: Immersion in distilled water provided greater solubility compared to PBS regardless of the experimental model (p<0.05). The test specimens showed greater solubility, followed by polyethylene and dentin models immersed in distilled water (p<0.05). There was no difference between the experimental models immersed in PBS (p>0.05). Conclusion: Bio-C Sealer presents significantly greater solubility in distilled water than in PBS under all conditions. Experimental model using bovine dentin and PBS as an immersion solution demonstrates reduction in the mass loss of Bio-C Sealer and can be a valuable alternative for evaluating the solubility of bioceramic sealers

A new proposal for evaluating of the solubility of bioceramic materials in dentin tubes after immersion in PBS: a laboratory investigation / Nova proposta para avaliação da solubilidade de materiais biocerâmicos em tubos de dentina após imersão em PBS: um estudo laboratorial

Introdução: Materiais reparadores devem apresentar baixa solubilidade. Solução salina tamponada com fosfato (PBS) permite simular condição clínica e interação com dentina pode ser importante para correta avaliação da perda de massa de cimentos biocerâmicos. Objetivo: Avaliou o efeito da imersão em água destilada (AD) ou PBS na solubilidade de Bio-C Repair (BCR, Angelus) ou MTA Repair HP (MTAHP, Angelus) usando modelo de tubo de dentina. Material e método: Tubos de dentina bovina foram confeccionados com 4 mm de comprimento, 1,5 mm de diâmetro interno e 1 mm aproximadamente de espessura de parede. Os espécimes foram imersos em AD por 24h, posteriormente preenchidos com BCR ou MTAHP (n = 14) e armazenados em estufa a 37°C e umidade 95% por 24h. Após serem pesados em balança de precisão para determinação da massa inicial, os corpos de prova foram imersos em AD (pH 6,5) ou PBS (pH 7,0) (n = 7) por 28 dias. Tubos vazios também foram utilizados para o cálculo de perda de massa da dentina (n=4). Após esse período, os espécimes foram pesados até a estabilização da massa final (0,001g). A solubilidade de cada material foi avaliada. Testes estatísticos ANOVA e Tukey foram realizados (α=0,05). Resultado: BCR e MTAHP apresentaram ganho de massa em AD e perda de massa em PBS (p<0,05). Conclusão: A solução de imersão influencia a solubilidade de BCR e MTAHP usando modelo de tubo de dentina. Nova proposta metodológica poderá ser uma alternativa às normas ISO para testar a solubilidade de cimentos biocerâmicos

Introduction: Repair materials must have low solubility. Phosphate buffered saline (PBS) allows simulating clinical condition and interaction with dentin may be important for the correct evaluate of mass loss of bioceramic cements. Objective: To evaluate the effect of distilled water (DW), or PBS immersion on the solubility of Bio-C Repair (BCR, Angelus) or MTA Repair HP (MTAHP, Angelus) using a dentin tube model. Material and method: Bovine dentin tubes with a length of 4 mm, an internal diameter of 1.5 mm and walls thickness of approximately 1 mm were made. The specimens were immersed in DW for 24h, then filled with BCR or MTAHP (n = 14) and stored in an oven at 37°C and 95% humidity for 24h. After being weighed on a precision balance to determine the initial mass, the specimens were immersed in DW (pH 6.5) or PBS (pH 7.0) (n = 7) for 28 days. Empty tubes also were used for calculating the mass loss of the dentin (n=4). After this period, the specimens were weighed until stabilization of the final mass occurred (0.001g). The solubility of each material was evaluated. ANOVA and Tukey statistical tests were performed (α=0.05). Result: BCR and MTAHP showing gain of mass in DW and mass loss in PBS (p<0.05). Conclusion: The immersion solution influenced the solubility of BCR and MTAHP using dentin tube model. The new methodological proposal could be an alternative to ISO standards for testing the solubility of bioceramic cement

Effect of adhesive primer application on shear bond strength of self-adhesive cement to tooth structure and two different CAD/CAM milled blocks / Efeito da aplicação do primer adesivo na resistência ao cisalhamento do cimento autoadesivo à estrutura dentária e a dois diferentes blocos fresados CAD/CAM

Objective: This study was conducted to evaluate the influence of the G-CEM ONE adhesive enhancing primer on the shear bond strength of self-adhesive resin cement (G-CEM ONE) to both tooth structure and two different CAD/CAM blocks (GC Initial LiSi and Cerasmart 270). Material and Methods: Forty specimens (cylindrical-shaped, 5 mm in diameter and height) were milled from both CAD/CAM blocks (20 specimens from each block type). Forty sound upper premolars were sectioned to the level of peripheral dentin, then randomly divided into four groups (n = 10): A1: GC Initial LiSi without adhesive enhancing primer; B1: Cerasmart 270 without adhesive enhancing primer; A2: GC Initial LiSi with adhesive enhancing primer; B2: Cerasmart 270 group with adhesive enhancing primer application. The CAD/CAM blocks were cemented on teeth using a self-adhesive resin cement (G-cem one). The shear bond strength was assessed using a computerized universal testing machine. A digital microscope was used to study the mode of failure. The shear bond strength values data were analyzed statistically using paired t-test and independent t-test at the significance level of (0.05). Results: A significant difference was shown in the shear bond strength values among groups (P =0.000). The highest shear bond strength value was revealed in group A2, while group B1 exhibited the lowest shear bond strength value. Conclusion: Using the adhesive enhancing primer on the tooth's surface improved the resin cement's bond strength to CAD/CAM blocks. Additionally, GC Initial LiSi exhibited higher bond strength than Cerasmart 270, with or without the primer (AU)

Objetivo: Este estudo foi conduzido para avaliar a influência do primer adesivo G-CEM ONE na resistência ao cisalhamento do cimento resinoso autoadesivo (G-CEM ONE) tanto na estrutura dentária quanto em dois diferentes blocos CAD/CAM (GC Initial LiSi e Cerasmart 270). Material e Métodos: Quarenta corpos de prova (formato cilíndrico, 5 mm de diâmetro e altura) foram fresados em blocos CAD/CAM (20 corpos de prova de cada tipo de bloco). Quarenta pré-molares superiores sadios foram seccionados até o nível da dentina mais externa e, em seguida, divididos aleatoriamente em quatro grupos (n = 10): A1: GC Initial LiSi sem primer adesivo; B1: Cerasmart 270 sem primer adesivo; A2: GC Initial LiSi com primer adesivo; B2: Grupo Cerasmart 270 com aplicação de primer adesivo. Os blocos CAD/CAM foram cimentados nos dentes com cimento resinoso autoadesivo (G-CEM ONE). A resistência ao cisalhamento foi avaliada utilizando uma máquina de ensaios universal computadorizada. Um microscópio digital foi utilizado para estudar o modo de falha. Os dados dos valores de resistência ao cisalhamento foram analisados estatisticamente por meio do teste t pareado e teste t independente ao nível de significância de (0,05). Resultados: Foi demonstrada diferença significativa nos valores de resistência ao cisalhamento entre os grupos (P =0,000). O maior valor de resistência ao cisalhamento foi revelado no grupo A2, enquanto o grupo B1 exibiu o menor valor de resistência ao cisalhamento. Conclusão:A utilização do primer adesivo na superfície dentária melhorou a resistência de união do cimento resinoso aos blocos CAD/CAM. Além disso, o GC Initial LiSi apresentou maior resistência de união que o Cerasmart 270, com ou sem primer.(AU)

Effect of 10% Proanthocyanidin gel on demineralized organic matrix degradation: ELISA method / Efeito do gel de Proantocianidina a 10% na degradação da matriz orgânica desmineralizada: método ELISA

Objective: This study evaluated Proanthocyanidin protective effect on dentin subjected to erosion and its inhibition on degradation of the demineralized organic matrix (DOM). Material and Methods: The tested groups were: G1 - 10% Proanthocyanidin gel (test group), G2 - 1.23% NaF (positive control 1), G3 - 0.012% Chlorhexidine (positive control 2) and G4 ­ Placebo (negative control with no active compound) and two methodologies were performed: contact profilometry and ICTP ELISA method. To quantify dentin wear, profilometry was performed. Data were submitted to Analysis of Variance followed by Fisher's LSD Test. To assess the collagen degradation, ICTP ELISA method was performed. Data were submitted to the Kruskal-Wallis followed by the Dunn ́s test. Simple linear regression and Pearson Correlation test were also performed (p<0.05). Results: The profilometry showed significantly lower wear of G1 when compared to other groups and G2, G3 and G4, which did not present significant difference among them. In the ICTP ELISA analysis, G1 and G4 did not show significant differences and the same happened between G2 and G3. However, G1 and G4 had lower values of collagen degradation compared to groups G2 and G3. Data showed that degraded DOM is a significant predictor to explain the values obtained through the ICTP ELISA. Conclusions: The results allow to verify that 10% proanthocyanidin provided less tooth wear and decreased degradation of the DOM, suggesting a good ability to prevent dentin erosion. The regression analysis also suggests that contact profilometry is a good strategy to quantify dentin wear (AU)

Objetivo: Este estudo avaliou o efeito protetor da proantocianidina na dentina submetida à erosão e sua inibição na degradação da matriz orgânica desmineralizada (MOD). Material e Métodos: Os grupos testados foram: G1 - gel de Proantocianidina 10% (grupo teste), G2 - NaF 1,23% (controle positivo 1), G3 - Clorexidina 0,012% (controle positivo 2) e G4 - Placebo (controle negativo sem princípio ativo) e duas metodologias foram realizadas: perfilometria de contato e método ICTP ELISA. Para quantificar o desgaste da dentina, a perfilometria foi realizada. Os dados foram submetidos à Análise de Variância seguida do Teste LSD de Fisher. Para avaliar a degradação do colágeno, foi realizado o método ICTP ELISA. Resultados: Os dados foram submetidos ao teste de Kruskal-Wallis seguido do teste de Dunn. Regressão linear simples e teste de correlação de Pearson também foram realizados (p<0,05). A perfilometria mostrou desgaste significativamente menor do G1 quando comparado aos outros grupos e G2, G3 e G4, que não apresentaram diferença significativa entre si. Na análise ICTP ELISA, G1 e G4 não apresentaram diferenças significativas e o mesmo ocorreu entre G2 e G3. No entanto, G1 e G4 apresentaram valores menores de degradação do colágeno em relação aos grupos G2 e G3. Os dados mostraram que a MOD degradada é um preditor significativo para explicar os valores obtidos pelo ICTP ELISA. Conclusão: Os resultados permitem verificar que a proantocianidina a 10% proporcionou menor desgaste dentário e diminuição da degradação da MOD, sugerindo uma boa capacidade de prevenir a erosão dentinária. Também sugere que a perfilometria de contato é uma boa estratégia para quantificar o desgaste da dentina (AU)

Effects of thermal cycling on bonding properties of novel low-shrinkage resin adhesive / 华西口腔医学杂志

OBJECTIVES@#The current study aimed to investigate the bonding properties of a novel low-shrinkage resin adhesive containing expanding monomer and epoxy resin monomer after thermal cycling aging treatment.@*METHODS@#Expanding monomer of 3,9-diethyl-3,9-dimethylol-1,5,7,11-tetraoxaspiro-[5,5] undecane (DDTU) as an anti-shrinkage additive and unsaturated epoxy monomer of diallyl bisphenol A diglycidyl ether (DBDE) as a coupling agent were synthesized. A blend of DDTU and DBDE at a mass ratio of 1∶1, referred to as "UE", was added into the resin matrix at the mass fraction of 20% to prepare a novel low-shrinkage resin adhesive.Then, the methacrylate resin adhesive without UE was used as the blank control group, and a commercial resin adhesive system was selected as the commercial control group. Moreover, the resin-dentin bonding and micro-leakage testing specimens were prepared for the thermal cycling aging treatment. The bonding strength was tested, the fracture modes were calculated, the bonding fracture surface was observed by scanning electron microscope (SEM), and the dye penetration was used to evaluate the tooth-restoration marginal interface micro-leakage. All the data were analyzed statistically.@*RESULTS@#After aging, the dentin bonding strength of the experimental group was (19.20±1.03) MPa without a significant decrease (P>0.05), that of the blank control group was (11.22±1.48) MPa with a significant decrease (P<0.05) and that of the commercial control group was (19.16±1.68) MPa without a significant decrease (P>0.05). The interface fracture was observed as the main fracture mode in each group after thermal cycling by SEM. The fractured bonding surfaces of the experimental group often occurred on the top of the hybrid layer, whereas those of the blank and commercial control groups mostly occurred on the bottom of the hybrid layer. Micro-leakage rating counts of specimens before and after thermal cycling were as follows: the experimental group was primarily 0 grade, thereby indicating that a relatively ideal marginal sealing effect could be achieved (P>0.05); meanwhile, the blank control group was primarily 1 grade, and the penetration depth of dye significantly increased after thermal cycling (P<0.05); the commercial control group was primarily 0 grade without statistical difference before and after thermal cycling (P>0.05), while a significant difference was observed between the commercial control group and experimental group after thermal cycling (P<0.05).@*CONCLUSIONS@#The novel low-shrinkage resin adhesive containing 20%UE exhibited excellent bonding properties even after thermal cycling aging treatment, thereby showing a promising prospect for dental application.

Effects of novel bioactive glasses on promoting remineralization of artificial dentin caries / 北京大学学报(医学版)

OBJECTIVE@#To investigate the effects of novel bioactive glasses (BG) including PSC with high phosphorus component and FBG with fluorine-doped element on promoting remineralization of artificial dentin caries.@*METHODS@#(1) BGs were used in this study as follows: PSC (10.8%P2O5-54.2%SiO2-35.0%CaO, mol.%) were synthesized using phytic acid as the phosphorus precursor through sol-gel method. FBG (6.1%P2O5-37.0%SiO2-53.9%CaO-3.0%CaF2, mol.%) and 45S5(6.0%P2O5-45.0%SiO2-24.5%CaO-24.5%Na2O, mol.%) were synthesized by traditional melt method. (2) The above BGs were soaked in simulated body fluid (SBF) for 24 hours. Then X-ray diffraction (XRD) was used to analyze the formation of hydroxyapatite (HA) crystals. (3) Prepared 1 mm thick dentin slices were soaked in 17% ethylene diamine tetraacetic acid (EDTA) for 1 week to demineralize the dentin. Then the dentin slices treated by BG were soaked in SBF for 1 week. Field emission scanning electron micro-scopy (FE-SEM) was used to observe the surface morphology of the dentin slices. (4) Four cavities were prepared to 1 mm depth in each 2 mm thick dentin slice, then were treated with lactic acid for 2 weeks to form the artificial dentin caries. Wax, mineral trioxide aggregate (MTA), PSC and FBG were used to fill four cavities as blank control group, MTA group, PSC group and FBG group respectively. Then the spe-cimens were soaked in SBF for 4 weeks. The changes of depth and density of demineralized dentin were analyzed using Micro-CT before filling and after 2 and 4 weeks filling.@*RESULTS@#(1) PSC and FBG promoted mineral formation on the surfaces of the demineralized dentin. And the speed was faster and crystallinity was higher in PSC group than the FBG and 45S5 groups. (2) The increased mineral density of artificial dentin caries in PSC group were (185.98 ± 55.66) mg/cm3 and (213.64 ± 36.01) mg/cm3 2 and 4 weeks after filling respectively, which were significantly higher than the control group [(20.38 ± 7.55) mg/cm3, P=0.006; (36.46 ± 10.79) mg/cm3, P=0.001]. At meanwhile, PSC group was also higher than MTA group [(57.29 ± 10.09) mg/cm3; (111.02 ± 22.06) mg/cm3], and it had statistical difference (P=0.015; P=0.006). The depth of remineralized dentin in PSC group were (40.0 ± 16.9) μm and (54.5 ± 17.8) μm 2 and 4 weeks respectively, which were also statistically different from the control group (P =0.010;P=0.001). There were no statistical differences between the control group and MTA group. The above effects of FBG group were between PSC and MTA.@*CONCLUSION@#PSC has advantages in the speed, quality and depth of mineral deposition in the demineralized layer of artificial dentin caries. It would be expected to be an ideal material to promote the remineralization of dentin caries.

Antibacterial effect of low-temperature plasma on Enterococcus faecalis in dentinal tubules in vitro / 北京大学学报(医学版)

OBJECTIVE@#To construct a model of Enterococcus faecalis (E. faecalis) infection in dentinal tubules by gradient centrifugation and to evaluate the antibacterial effect of low-temperature plasma on E. faecalis in dentinal tubules.@*METHODS@#Standard dentin blocks of 4 mm×4 mm×2 mm size were prepared from single root canal isolated teeth without caries, placed in the E. faecalis bacterial solution, centrifuged in gradient and incubated for 24 h to establish the model of dentinal tubule infection with E. faecalis. The twenty dentin blocks of were divided into five groups, low-temperature plasma jet treatment for 0, 5 and 10 min, calcium hydroxide paste sealing for 7 d and 2% chlorhexidine gel sealing for 7 d. Scanning electron microscopy and confocal laser scanning microscope were used to assess the infection in the dentinal tubules and the antibacterial effect of low-temperature plasma.@*RESULTS@#The results of scanning electron microscopy and confocal laser scanning microscopy showed that after 24 h of incubation by gradient centrifugation, E. faecalis could fully enter the dentinal tubules to a depth of more than 600μm indicating that this method was time-saving and efficient and could successfully construct a model of E. faecalis infection in dentinal tubules. Low-temperature plasma could enter the dentinal tubules and play a role, the structure of E. faecalis was still intact after 5 min of low-temperature plasma treatment, with no obvious damage, and after 10 min of low-temperature plasma treatment, the surface morphology of E. faecalis was crumpled and deformed, the cell wall was seriously collapsed, and the normal physiological morphology was damaged indicating that the majority of E. faecalis was killed in the dentinal tubules. The antibacterial effect of low-temperature plasma treatment for 10 min exceeded that of the calcium hydroxide paste sealing for 7 d and the 2% chlorhexidine gel sealing for 7 d. These two chemicals had difficulty entering deep into the dentinal tubules, and therefore only had a few of antibacterial effect on the bacterial biofilm on the root canal wall, and there was also no significant damage to the E. faecalis bacterial structure.@*CONCLUSION@#Gradient centrifugation could establish the model of E. faecalis dentin infection successfully. Low-temperature plasma treatment for 10 min could kill E. faecalis in dentinal tubules effectively, which is superior to the calcium hydroxide paste sealing for 7 d and the 2% chlorhexidine gel sealing for 7 d.

Applications of collagen extrafibrillar demineralization in dentin bonding / 中华口腔医学杂志

The existing dentin bonding systems based on acid-etching technique lead to the loss of both extrafibrillar and intrafibrillar minerals from dentin collagen, causing excessive demineralization. Because resin monomers can not infiltrate the intrafibrillar spaces of demineralized collagen matrix, degradation of exposed collagen and resin hydrolysis subsequently occur within the hybrid layer, which seriously jeopardizing the longevity of resin-dentin bonding. Collagen extrafibrillar demineralization can effectively avoid the structural defects within the resin-dentin interface caused by acid-etching technique and improve the durability of resin-dentin bonding, by preserving intrafibrillar minerals and selectively demineralizing extrafibrillar dentin. The mechanism and research progress of collagen extrafibrillar demineralization in dentin bonding are reviewed in the paper.

Mutation of dentin sialophosphoprotein and hereditary malformations of dentin / 中华口腔医学杂志

The classification as well as the clinical manifestations of hereditary malformations of dentin are of great concern and have been deeply elucidated. The understanding of its genetic basis also increases progressively. Dentin sialophosphoprotein (DSPP) is the pathogenic gene of dentinogenesis imperfecta type Ⅱ, dentinogenesis imperfecta type Ⅲ and dentin dysplasia type Ⅱ. In this article, the classification of DSPP mutations as well as the resultant dysfunction of the mutant DSPP are summarized respectively and the corresponding clinical manifestations are analyzed. This work will provide a reference for the diagnosis and treatment of hereditary malformations of dentin.

Efeito de doses terapêuticas de radioterapia sobre a morfologia, composição química e microdureza do esmalte e da dentina de dentes permanentes / Effect of therapeutic doses of radiotherapy on the morphology, chemical composition, and microhardness of enamel and dentin of permanent teeth

Introdução: Padrões atípicos de cárie dentária em pacientes submetidos a radioterapia para o tratamento do câncer de cabeça e pescoço podem estar associados aos efeitos da radiação sobre as glândulas salivares e tecidos dentários duros. Somados, podem contribuir para a cárie relacionada a radiação. Embora haja evidências sobre alterações sofridas pelos tecidos dentários duros após radioterapia, não há consenso na literatura sobre a gravidade destas alterações. Objetivo: avaliar a microestrutura, composição química e microdureza do esmalte e da dentina de dentes permanentes submetidos a doses terapêuticas de radioterapia in vitro. Material e métodos: estudo experimental, qualitativo, quantitativo e semiquantitativo. Foram obtidos fragmentos coronários de 24 terceiros molares. Constituiuse 2 grupos: NIR (controle): formado por fragmentos de dentes não irradiados e IVT (irradiado): formado por fragmentos de dentes irradiados in vitro (2 Gy/dia 5 vezes por semana, totalizando 70 Gy). Os fragmentos foram submetidos a análise da microdureza (n=24), Espectroscopia de Infravermelho com Transformada de Fourier (FTIR) (n=24), análise morfológica através de Microscopia Eletrônica de Varredura (MEV) (n=19) e análise de elementos químicos por Espectroscopia de Dispersão de Energia de Raio X (EDX) (n=19). As análises foram feitas antes e após a irradiação. Os dados foram testados para distribuição normal (teste de Shapiro-Wilk, α = 0,05) e igualdade de variâncias (teste de Levene, α = 0,05), seguido de testes estatísticos paramétricos. Para a comparação das variáveis quantitativas foi aplicado o teste T de Student. Um valor de p <0,05 (5%) foi considerado estatisticamente significativo. Resultados: em relação as propriedades mecânicas observamos redução significativa da microdureza do esmalte e dentina após irradiação (p<0,001). A análise da composição química por FTIR mostrou que no esmalte não houve alteração da razão matriz/mineral (M:M) no grupo irradiado (p<0,821), mas houve redução significativa do teor relativo de carbonato (RCC) após irradiação (p<0,039). Na dentina observamos redução significativa da razão matriz/mineral (M:M) e carbonato/mineral (C:M) no grupo irradiado (p<0,001), enquanto a razão amida I/amida III, não sofreu alteração significativa após irradiação (p<0,536). Na análise de EDX realizadas no esmalte, não observamos variação no conteúdo de cálcio e fósforo após radiação, mas a razão Ca/P mostrou-se significantemente mais elevada no grupo irradiado (p<0,001). Na dentina, não houve alteração do teor de cálcio e fósforo, assim como da razão Ca/P após irradiação (p<0,267). A análise morfológica através de MEV pós irradiação, mostrou que no esmalte a maioria das amostras apresentaram uma alteração das características microestruturais com a presença de microporosidades, perda de padrões regulares das áreas prismáticas e interprismáticas e presença de áreas amorfas. Na dentina observamos manutenção do padrão de dentina peritubular e intertubular, com a presença de túbulos dentinários desobliterados e com a rede de fibras colágenas mais evidente grupo irradiado. Conclusão: as doses terapêuticas de radioterapia provocaram redução da microdureza, alterações na microestrutura e composição química do esmalte e da dentina. Assim, inferimos que doses terapêuticas de radiação exercem um impacto negativo sobre as propriedades mecânicas, químicas e micro-morfológicas dos tecidos dentários duros aumentando a vulnerabilidade destes tecidos à cárie relacionada a radiação.

INTRODUCTION: Atypical patterns of dental caries in patients undergoing radiotherapy to treat head and neck cancer may be associated with the effects of radiation on salivary glands and dental hard tissues. Together, they can contribute to radiation-related caries. Although there is evidence of changes in hard dental tissues after radiotherapy, there is no agreement in the literature on the severity of these changes. PURPOSE: This study aims to evaluate the microstructure, chemical composition, and microhardness of enamel and dentin in permanent teeth subject to therapeutic doses of in vitro radiotherapy. MATERIAL AND METHODS: This is an experimental, qualitative, quantitative, and semi-quantitative study. Coronary fragments were obtained from 24 third molars. Two groups were created: NIR (control), including fragments of non-irradiated teeth, and IVT (irradiated), including fragments of in vitro irradiated teeth (2Gy/day five times a week, totaling 70Gy). The fragments underwent microhardness analysis (n =24), Fourier-transform Infrared Spectroscopy (FTIR) (n=24), morphological analysis by Scanning Electron Microscope (SEM) (n=19), and analysis of chemical elements by Energy-dispersive X-Ray Spectroscopy (EDX) (n=19). The analyses were performed before and after irradiation. Data were tested for normal distribution (ShapiroWilk test, α = 0.05) and equality of variances (Levene test, α = 0.05), followed by parametric statistical tests. The Student's T test was applied to compare the quantitative variables. A pvalue < 0.05 (5%) was considered statistically significant. RESULTS: Concerning the mechanical properties, we observed a significant reduction in enamel and dentin microhardness after irradiation (p<0.001). The analysis of the chemical composition by FTIR showed no change in the mineral/matrix ratio (M:M) in enamel in the irradiated group (p<0.821), but there was a significant reduction in the relative carbonate content (RCC) after irradiation (p<0.039). In dentin, we observed a significant reduction in the mineral/matrix ratio (M:M) and carbonate/mineral ratio (C:M) in the irradiated group (p<0.001). In contrast, the amide I/amide III ratio showed no significant change after irradiation (p<0.536). In the EDX analysis performed on enamel, we did not observe any calcium and phosphorus content variation after radiation. However, the Ca/P ratio was significantly higher in the irradiated group (p<0.001). In dentin, there was no change either in calcium and phosphorus contents or in the Ca/P ratio after irradiation (p<0.267). The morphological analysis through SEM after irradiation showed that there is a loss in the characteristics of the enamel surface of most fragments, with the presence of microporosities, loss of regular patterns of the prismatic and interprismatic areas, and the presence of amorphous areas. In dentin, we observed maintenance of the peritubular and intertubular dentin patterns, with the presence of unobliterated dentinal tubules and with the most evident network of collagen fibers in the irradiated group. CONCLUSION: Therapeutic doses of radiotherapy caused a reduction in microhardness and changes in the microstructure and chemical composition of enamel and dentin. Thus, we conclude that therapeutic doses of radiation have a negative impact on the mechanical, chemical, and micromorphological properties of hard dental tissues, increasing the vulnerability of these tissues to radiation-related caries

Dimensions of Occlusoproximal Cavitated Carious Lesions as a Cut-Off Point for Restorative Decision in Primary Teeth

ABSTRACT Objective: To investigate whether the dimensions of cavitated dentin carious lesions on the occlusoproximal surfaces of primary teeth could predict the location of cement-enamel junction (CEJ). Material and Methods: Two hundred extracted primary molars were selected and digital images were obtained. The teeth were set in arch models for clinical measurement. The cervical-occlusal (CO) and buccal-lingual/palatal (BL/P) cavities' dimensions were obtained by digital (Image J) and clinical (periodontal millimeter probe) assessments. The cervical margin location was also determined. The thresholds (cut-off points) were determined by sensitivity, specificity and the areas under the receiver operating characteristics curves (Az) for the two methods. Pearson's correlation coefficient was used to investigate the correlation between clinical and digital measurements. Logistic regression analysis was performed to evaluate the association between the dimensions and cervical margin location. Results: There was a strong correlation between methods for all measurements (CO: r=0.90, VL/P: r=0.95). Cavities with BL/P distance higher than 4.5 mm and CO dimension higher than 3.5 mm had a lower chance of presenting the cervical limit above the CEJ, irrespective of the measurement method. Conclusion: CO and VL/P dimensions could be used to predict the CEJ location and, ultimately, as a clinical parameter for restorative decision-making.

Effects of using different root canal sealers and protocols for cleaning intraradicular dentin on the bond strength of a composite resin used to reinforce weakened roots / Efectos del uso de diferentes selladores de conductos radiculares y protocolos para limpiar la dentina intrarradicular sobre la fuerza de unión de una resina compuesta utilizada para reforzar raíces debilitadas

Background: This study evaluated the effects of using different root canal sealers and protocols for cleaning intraradicular dentin on the bond strength of a composite resin used to reinforce weakened roots. Material and Methods: Sixty-four roots of extracted human maxillary canines were weakened, prepared and filled with two different endodontic sealers (Endofill and AH Plus). In half of the sample, set aside for each respective sealer, excess filling material was cleaned. In the other half, the weakened areas were not cleaned, and the excess of sealer was spread on the intraradicular dentin. Intentionally worn areas inside each root were restored with a microhybrid light-cure composite resin (Z100) to reinforce them, with and without acid etching. Prefabricated metal posts were fixed with a dual resin cement (RelyX ARC), and the specimens were submitted to a pull-out test. Statistical analysis was performed by means of Shapiro-Wilk, analysis of variance (one-way ANOVA) and Tukey-Kramer tests (p<0.05). Results: The groups filled with Endofill (GI, GII, GIII, GIV) had the lowest bond strength values, which were similar among each other (p>0.05).The greatest bond strength values were observed in roots filled with AH Plus (GV, GVI, GVII, GVIII), mainly without cleaning of the weakened areas, and followed by acid etching (GVII), and also with cleaning of the weakened areas, however, with no acid etching (GVI) (p<0.05). Conclusion: The greatest bond strength values were observed in roots filled with AH Plus; (1) without cleaning of the weakened areas and with acid etching, and; (2) with cleaning of the weakened areas, but without acid etching.

Antecedentes: este estudio evaluó los efectos del uso de diferentes selladores de conductos radiculares y protocolos para limpiar la dentina intrarradicular sobre la fuerza de unión de una resina compuesta utilizada para reforzar las raíces debilitadas. Material y Métodos: Sesenta y cuatro raíces de caninos maxilares humanos extraídos fueron debilitadas, preparadas y rellenadas con dos selladores endodónticos diferentes (Endofill y AH Plus). En la mitad de la muestra, reservada para cada sellador respectivo, se limpió el exceso de material de relleno. En la otra mitad, las áreas debilitadas no se limpiaron y el exceso de sellador se esparció sobre la dentina intrarradicular. Las áreas desgastadas intencionalmente dentro de cada raíz se restauraron con una resina compuesta fotopolimerizable microhíbrida (Z100) para reforzarlas, con y sin grabado ácido. Los postes metálicos prefabricados se fijaron con un cemento de resina dual (RelyX ARC) y los especímenes se sometieron a una prueba de extracción. El análisis estadístico se realizó mediante Shapiro-Wilk, análisis de varianza (ANOVA de una vía) y pruebas de Tukey-Kramer (p<0,05). Resultados: Los grupos rellenos con Endofill (GI, GII, GIII, GIV) presentaron los valores más bajos de fuerza de unión, los cuales fueron similares entre sí (p>0,05). Los mayores valores de fuerza de unión se observaron en raíces rellenas con AH Plus (GV, GVI, GVII, GVIII), principalmente sin limpieza de las áreas debilitadas, seguido de grabado ácido (GVII), y también con limpieza de las áreas debilitadas aunque sin grabado ácido (GVI) (p<0.05). Conclusión: Los mayores valores de fuerza de unión se observaron en las raíces rellenas con AH Plus; (1) sin limpieza de las áreas debilitadas y con grabado ácido, y; (2) con limpieza de las áreas debilitadas, pero sin grabado ácido.