Effect of sodium/calcium hypochlorite on adhesion and adaptation of fiber posts luted with a dual resin cement

Abstract This study aimed to evaluate the effect of different concentrations of sodium hypochlorite (NaOCl) and calcium hypochlorite [Ca(OCl)2] on the bond strength and adaptation of glass fiber posts luted with a dual-curing resin cement. Fifty decoronated premolars were sectioned 14 mm from the apex and endodontically treated. The root canal filling was partially removed. The specimens were divided into 5 groups (n=10) according to the irrigant for post space irrigation: 0.9% sodium chloride (NaCl), (control); 2.5% NaOCl; 5.25% NaOCl; 2.5% Ca(OCl)2; and 5.25% Ca(OCl)2. For each group, irrigation was performed with 5 ml of solution. Afterward, the posts were luted with a dual-curing resin cement. One slice from each third was obtained and submitted to the push-out test and failure modes analysis. An additional slice from the middle third was submitted to confocal images for analysis of adaptation failures (gaps). Two-way ANOVA, Tukey's post-hoc, Kruskal-Wallis with Bonferroni adjusted, and chi-square tests, analyzed data. The group treated with 5.25% NaOCl showed lower bond strength values and generated more cohesive failures compared to the control (p < 0.05). Bond strength decreased from coronal to apical in the post space (p < 0.001). The groups treated with NaOCl had the highest percentages of gaps compared to the control (p < 0.05). Regardless of concentration, Ca(OCl)2 did not influence the bond strength and the occurrence of gaps (P > 0.05). Ca(OCl)2 is a good option for irrigating the post space before luting a fiber post with a dual-curing resin cement.

Resumo Este estudo teve como objetivo avaliar o efeito de diferentes concentrações de hipoclorito de sódio (NaOCl) e hipoclorito de cálcio [Ca(OCl)2] na resistência de união e adaptação de pinos de fibra de vidro cimentados com um cimento resinoso dual. Cinquenta pré-molares tiveram suas coroas removidas, foram seccionados a 14 mm do ápice e tratados endodonticamente. A obturação do canal radicular foi parcialmente removida. Os espécimes foram divididos em 5 grupos (n=10) de acordo com o irrigante para irrigação do espaço do pino: cloreto de sódio 0.9% (NaCl), (controle); NaOCl 2.5%; NaOCl 5.25%; Ca(OCl)2 2.5%; e Ca(OCl)2 5.25%. Para cada grupo, a irrigação foi realizada com 5 ml da solução. Posteriormente, os pinos foram cimentados com um cimento resinoso dual. Uma fatia de cada terço foi obtida e submetida ao teste push-out e análise dos modos de falha. Um corte adicional do terço médio foi submetido a imagens confocais para análise de falhas de adaptação (gaps). Os dados foram analisados pelos testes ANOVA de duas vias, post-hoc de Tukey, Kruskal-Wallis com ajuste de Bonferroni e qui-quadrado. O grupo tratado com NaOCl 5.25% apresentou menores valores de resistência de união e gerou mais falhas coesivas em relação ao controle (p < 0.05). A resistência de união diminuiu de coronal para apical no espaço do pino (p < 0.001). Os grupos tratados com NaOCl apresentaram os maiores percentuais de gaps em relação ao controle (p < 0.05). Independentemente da concentração, o Ca(OCl)2 não influenciou a resistência de união e a ocorrência de gaps (P > 0.05). O Ca(OCl)2 é uma boa opção para irrigar o espaço do pino antes de cimentar um pino de fibra com um cimento resinoso dual.

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)

Application prospect of polyetheretherketone in postcore crown restorations / 口腔疾病防治

@#Polyetheretherketone (PEEK) is known as a high-grade engineering plastic with good mechanical properties, chemical stability and biocompatibility. Currently, PEEK materials have been widely used in prosthodontics, such as complete dentures and removable partial dentures. The relevant research shows that PEEK posts are superior to glass fiber posts, which have high tensile bond strength and bending strength. At present, few case reports of PEEK postcores have been published, and clinical case reports suggest that PEEK postcores have good oral prosthetic aesthetics and are ideal and reliable postcore crown materials. However, the preparation and surface treatment methods of PEEK require further refinement. A review of the related properties of PEEK and the prospects of its application in the field of postcore crown restoration will be presented in this paper.

Evaluation of The Cleaning Protocol of Post Space on Bond Strength of Glass Fiber Posts

ABSTRACT: This study aimed to compare the effect of four irrigation solutions for post space cleaning on the bond strength between glass fiber post and root dentine. Forty bovine roots were root-filled and randomly divided into four groups (n=10), according to the irrigation solution: CG (Control Group): saline solution; SH (Sodium Hypochlorite Group); CLX (Chlorhexidine group) and EDTA (ethylenediaminetetraacetic acid group). Specimens were submitted to mechanical aging and push-out test. Statistical analysis (ANOVA two-way and Tukey test; p<0.05) was performed. A stereomicroscope was used for failure mode classification. EDTA showed higher bond strength values, differing statistically from SH and CG (p<0.05). Adhesive failure between dentin and resinous cement was predominant, followed by mixed failures. SEM images showed pronounced smear layer removal in the EDTA group. 17 % EDTA was better than other solutions for cleaning of post space when using glass fiber posts.

RESUMEN: Este estudio tuvo como objetivo comparar el efecto de cuatro soluciones de irrigación para la limpieza del espacio del poste sobre la fuerza de unión entre el poste de fibra de vidrio y la dentina radicular. Se rellenaron cuarenta raíces bovinas y se dividieron aleatoriamente en cuatro grupos (n = 10), según la solu- ción de riego: CG (Grupo Control): solución salina; SH (Gru- po de hipoclorito de sodio); CLX (grupo clorhexidina) y EDTA (grupo ácido etilendiaminotetraacético). Las muestras se sometieron a una prueba de envejecimiento mecánico y de expulsión. Se realizó análisis estadístico (ANOVA bidireccional y prueba de Tukey; p <0,05). Se utilizó un microscopio estereoscópico para la clasificación del modo de falla. EDTA mostró valores de fuerza de unión más altos, difiriendo estadísticamente de SH y CG (p <0,05). Pre-dominó la falla adhesiva entre dentina y cemento resinoso, seguida de fallas mixtas. Las imágenes SEM mostraron una eliminación pronunciada de la capa de frotis en el grupo de EDTA. El EDTA al 17 % fue mejor que otras soluciones para la limpieza del espacio de los postes cuando se utilizan postes de fibra de vidrio.

Evaluation of stress in three different fiber posts with two-dimensional finite element analysis

Introduction: The primary function of corono-radicular post is to provide retention for the core and to reinforce and to replace the remaining coronal tooth structure. There is considerable controversy regarding optimal choice of the material. An ideal post system should exhibit fracture resistance higher than the average masticatory forces. Finite elemental analysis (FEA) method facilitates precise analysis of the distribution and magnitude of stresses at any point of complex and irregular structures. Thus, this FEA study has been undertaken to evaluate the fracture stress distribution patterns in three fiber posts, viz., carbon, glass fiber, and everStick with an FEA. Materials and Methods: The FE stress analysis was performed with the FE software program (CATIA). Three two-dimensional FEA models of central incisor were simulated, and elastic moduli and Poisson's ratio of all the materials were fed to the software. For all the models, a 200 N vertical force was applied on the lingual surface of the tooth at an angle of 45°. Stress concentration and distribution were evaluated and noted down for all the models. To evaluate the stresses within the restored tooth, the modified von Mises failure criterion was used. The equivalent stresses found in the tested models were compared with the tensile strength of the respective materials. Contact stresses in the luting cement–dentin interface were calculated. Results: Finite element method revealed that maximum stress concentration was at the point of stress application. The stress value was highest in carbon fiber post followed by glass fiber post and least stresses found in everStick post. Maximum stress was observed at the labial surfaces of crown. However, the stress values and distribution were more homogenous in everStick post. Conclusion: The present findings suggest that everStick post has uniform stress distribution within tooth structure.

Resistência de união de pinos de fibra de vidro utilizando diferentes tratamentos radiculares / Resistencia a la unión de postes de fibra de vidrio utilizando diferentes tratamientos endodónticos / Bond strength of glass fiber posts using different endodontic treatments

Resumo Introdução: Os pinos de fibra de vidro têm sido amplamente utilizados na reconstrução de elementos com perda excessiva de estrutura dentária. Objetivo: Avaliar a força de adesão de pinos de fibra de vidro após diferentes tratamentos radiculares em diferentes regiões (terço cervical, médio e apical) da dentina radicular. Métodos: Este é um estudo experimental in vitro. Quarenta dentes bovinos foram selecionados, preparados e distribuídos em quatro grupos de acordo com o tratamento de superfície utilizado: adesivo (1), agente quelante (2), ácido poliacrílico (3), não tratado (4). A cimentação dos pinos de fibra de vidro foi realizada com cimento resinosante autocondicionante. Após vinte dias, cada raiz foi cortada em três fatias (um milímetro de espessura) obtidas de três regiões. A resistência de união de cada seção foi determinada usando um teste de resistência da junta de encaixe. Os dados de resistência à flexão (MPa) foram analisados pelos testes ANOVA e Tukey (α = 0,05). Resultados: Na porção cervical, o grupo com tratamento prévio com ácido poliacrílico apresentou menor resistência ao cisalhamento por extrusão (push-out) do que o grupo sem tratamento prévio. O grupo com aplicação do sistema adesivo (28,89 ± 6,64 MPa) e o grupo com tratamento prévio com EDTA (21,58 ± 6,39 MPa) não apresentaram diferenças estatisticamente significantes em relação ao grupo sem tratamento prévio (grupo controle) no terço cervical. Nas porções média e apical, o grupo tratado com adesivo FGM Ambar apresentou maiores valores de ligação em comparação com os outros grupos. Conclusão: A aplicação prévia do adesivo aumentou a resistência de união nos terços médio e apical, em comparação aos outros grupos, podendo ter um efeito benéfico no sucesso clínico do tratamento restaurador(AU)

Resumen Introducción: Los postes de fibra de vidrio se han utilizado ampliamente en la reconstrucción de elementos con pérdida excesiva de estructura dental. Objetivo: Evaluar la fuerza de adhesión de postes de fibra de vidrio después de distintos tratamientos de raíz en diferentes regiones (tercios cervical, medio y apical) de dentina de raíz. Métodos: Estudio experimental in vitro. Se seleccionaron cuarenta dientes bovinos, se prepararon y se distribuyeron en cuatro grupos de acuerdo con el tratamiento de superficie utilizado: (1) adhesivo, (2) agente quelante, (3) ácido poliacrílico, (4) sin tratar. La cementación de los postes de fibra de vidrio se realizó con cemento de resina autograbante. Después de 20 días, cada raíz se seccionó transversalmente en tres rodajas (1 mm de espesor) obtenidas de tres regiones. La resistencia a la unión de cada sección se determinó usando una prueba de resistencia al corte por extrusión (push-out). Los datos de resistencia a la flexión (MPa) se analizaron mediante pruebas ANOVA y Tukey (α = 0,05). Resultados: En la porción cervical, el grupo con tratamiento previo de ácido poliacrílico mostró menor resistencia que el grupo sin tratamiento previo. El grupo con aplicación del sistema adhesivo (28,89 ± 6,64 MPa) y el grupo con tratamiento previo de EDTA (21,58 ± 6,39 MPa) no presentaron diferencias estadísticamente significativas en comparación con el grupo sin tratamiento previo (grupo control) en el tercio cervical. En las porciones media y apical, el grupo tratado con adhesivo Ambar® de FGM Dental Group mostró valores más altos de unión en comparación con los otros grupos. Conclusión: La aplicación previa del adhesivo aumentó la fuerza de unión en los tercios medio y apical, en comparación con los otros grupos, puede tener un efecto beneficioso sobre el éxito clínico del tratamiento restaurador(AU)

ABSTRACT Introduction: Glass fiber posts have been widely used for the reconstruction of elements with excessive dental structure loss. Objective: Evaluate the bond strength of glass fiber posts after various root dentin treatments in different regions (cervical, middle and apical thirds). Methods: An experimental in vitro study was conducted. Forty bovine teeth were selected, prepared and distributed into four groups according to the surface treatment used: (1) adhesive, (2) chelating agent, (3) polyacrylic acid, (4) not treated. The glass fiber posts were cemented with self-etch resin cement. After 20 days, each root was sectioned crosswise into three slices (1 mm in thickness) obtained from three regions. Bond strength was determined in each section with a push-out bond strength test. Flexural strength data (MPa) were analyzed with ANOVA and Tukey's tests. Results: In the cervical portion, the group with previous polyacrylic acid treatment displayed lower push-out strength than the group without previous treatment. The group with application of the adhesive system (28.89 ± 6.64 MPa) and the group with previous EDTA treatment (21.58 ± 6.39 MPa) did not exhibit any statistically significant differences in comparison with the group without previous treatment (control group) in the cervical third. In the middle and apical portions, the group treated with the adhesive Ambar® of FGM Dental Group showed higher bond values in comparison with the other groups. Conclusion: Previous adhesive application increased bond strength in the middle and apical thirds in comparison with the other groups, and may thus have a beneficial effect on the clinical success of the restorative treatment(AU)

Oval versus circular-shaped root canals: bond strength reached with varying post techniques

Abstract The aim of this study was to compare the bond strength (BS) of glass fiber posts (GFP) luted to oval and circular-shaped root canals rehabilitated using varying post techniques, at different intraradicular levels. Ninety 16-mm-long roots of human mandibular premolars, classified either as having oval or circular-shaped canals, were endodontically treated and prepared for restoration using one of three different post techniques (n=15): 1) single GFP; 2) resin-relined GFP; 3) main GFP associated with accessory posts. GFPs were luted with a dual polymerizing resin cement (RelyX ARC) after the canal had been treated with a 3-step etch-and-rinse adhesive system (Adper Scothbond Multipurpose). The samples were sectioned into three 1-mm-thick sections, which were differentiated by the root level (cervical, middle and apical) and tested for push-out BS. Assessment of failure mode was made under a stereomicroscope. Data were analyzed using repeated measures three-way ANOVA and Tukey's test. The root canal cross-section had a significant influence on BS (p<0.001), with the lowest values being observed in oval-shaped canals. The post technique also significantly affected the BS (p=0.018), with the resin-relined GFPs providing the highest BS values in both oval and circular-shaped canals. Irrespective of the cross-section of the root canal and post technique, there was no significant difference in BS in the cervical, middle and apical third of the root canal (p=0.084). In oval-shaped canals, the BS to intraradicular dentin at cervical, middle or apical level could be increased when the GFPs posts were relined.

Resumo O objetivo deste estudo foi comparar a resistência de união (RU) de pinos de fibra de vidro (PFV), cimentados a condutos com secção transversal ovalada ou circular reabilitados com diferentes técnicas de restauração com PFVs, em função do nível intrarradicular. Noventa raízes de pré-molares inferiores humanos, com 16 mm de altura, classificadas como possuindo canais ovais ou circulares, foram tratadas endodonticamente e preparadas para serem reabilitadas com uma das três técnicas de restauração com PFVs (n=15): 1) PFV único, 2) PFV reembasado com resina composta, e 3) PFV principal associado a pinos acessórios. Os PFVs foram cimentados com um agente resinoso de polimerização dupla (RelyX ARC), após o canal ter sido tratado com um sistema adesivo de condicionamento total de três passos (Adper Scothbond Multiuso). As amostras foram seccionadas em três fatias de 1 mm de espessura, de acordo com o nível da raiz (cervical, médio e apical)e foram submetidas ao teste de RU por push-out. A análise do modo de falha foi realizada com auxílio de um estereomicroscópio. Os dados foram analisados utilizando-se a ANOVA a três critérios para medidas repetidas e o teste de Tukey. A secção do conduto apresentou influência na RU (p<0,001), com os menores valores sendo observados nos condutos ovalados. A técnica de restauração com PFVs afetou significativamente a RU (p=0,018), tendo o PFV reembasado proporcionado os maiores valores de RU, tanto em condutos ovais quanto circulares. Independentemente da secção transversal do conduto radicular e da técnica de restauração com PFV, não houve diferença significativa na RU nos terços cervical, médio e apical (p=0,084). Nos canais de secção transversal ovalada, a RU à dentina intrarradicular nos níveis cervical, médio ou apical aumentou com o emprego de PFVs reembasados.

Evaluación de la resistencia adhesiva entre el poste de fibra de vidrio y el muñón de resina utilizando diferentes tratamientos de superficie / Tensile Bond strength evaluation between glass fiber post and resin core using different surface treatments

La calidad de unión entre la superficie del poste de fibra de vidrio y el muñón es esencial para formar un solo núcleo. Si esta unión es afectada, ocasionaría una mala distribución de las fuerzas oclusales. Objetivos: Comparar la resistencia adhesiva entre el poste de fibra de vidrio y muñón de resina utilizando diferentes tratamientos de superficie. Material y métodos: La resistencia adhesiva se evaluó mediante el método de tracción. El diseño del estudio fue analítico, corte transversal y experimental in vitro.La población estuvo conformada por postes de fibra de vidrio estériles. El tamaño muestral fue de 24 postes; fueron divididos en cuatro grupos según el tratamiento de superficie: Grupo I, control negativo, con silano (60s); grupo II, control positivo, con peróxido de hidrógeno al 9%(30 volúmenes, 10min) seguido de lavado y silano (60s); grupo III y IV, grupos experimentales, con ácido fosfórico al 37%(15s) lavado y silano(60s) y con clorhexidina al 2%(60s) lavado y silano (60s).Luego, se elaboró un muñón para cada poste, la muestra fue colocada en la máquina de ensayo universal. La fuerza de tracción fue recopilada en Mpa. Resultados: Se determinó que el grupo silano obtuvo una media de 15,38; peróxido de hidrógeno al 9%+silano 20,28; ácido fosfórico al 37%+silano17,08; y clorhexidina al 2%+silano 13,44 Según la prueba de Shapiro Wilk, los cuatro grupos presentan distribución normal (p>0,05) y siguiendo la prueba de Barlett, se aprobó el supuesto de homogeneidad (p>0,05). Mediante la prueba multivariada de ANOVA; se determinó que existe diferencia estadística (p=0,0194), al menos, en un par de los cuatro grupos. Conclusiones: Existe diferencia estadísticamente significativa entre el grupo de peróxido de hidrógeno al 9%(30 volúmenes, 10 min)+silano(60s) y clorhexidina al 2%(60s)+silano(60s) (p=0,025), siendo el primero, la sustancia con mayor resistencia adhesiva.

The interface quality between the glass fiber post surface and core is essential to form a monoblock. If this interface is affected, a wrong distribution of occlusal forces could be caused. Objectives: To determine the bond strength between the glass fiber post and the resin core using different post surface treatments. Material and methods: The bond strength was evaluated by the traccional method. The study design was analytical, cross-sectional and experimental in vitro. The population were sterilized glass fiber posts. The sample size were 24 posts which were divided into four groups following the post surface treatment: Group I, negative control, with silane (60s); group II, positive control, with 9% hydrogen peroxide (30 volumes, 10min) followed by cleansing and silane (60s); groups III and IV, experimental groups, with phosphoric acid 37%(15s) followed by cleansing and silane(60s) and with clorhexidine 2%(60s) followed by cleansing and silane(60s). Therefore, a resin core was devised for each post, the sample was placed in the universal traction machine. The tensile force was collected in Mpa. Results: It was determined that the silane group obtained a mean of 15.38, 9% hydrogen peroxide+silane group 20.28, phosphoric acid 37%+silane group 17.08, and Clorhexidine 2% + silane group 13.44. According to the Shapiro-Wilk test, all four groups presented normal distribution (p>0.05) and following Barlett's test, the homogeneity of variances assumption was approved (p>0.05). Through the multifactor ANOVA test, it was determined that there is statistically significant difference (p=0.0194), at least in a couple of four groups. Conclusions: There is statistically significant difference between 9% hydrogen peroxide(30 volumes, 10min)+silane(60s) group and the Clorhexidine 2% (60s)+ silane(60s) group (p=0,025). Being the former glass surface treatment, the highest bond strength.

Observation of 120 cases of teeth with severe wedge-shaped defect treated with glass fiber post combined ;with gingival retraction / 中国基层医药

Objective To observe the effect of glass fiber post combined with gingival retraction in the treat-ment of teeth with severe wedge -shaped defect.Methods 53 patients with 120 teeth treated for severe wedge -shaped defect were selected.All the teeth were given root canal treatment,glass fiber post was applied after root canal prepared and resin was applied to fill wedge-shaped defect after gingival retraction.All the teeth were followed up for 2-3 years.Results In 2-3 years follow-up after treatment,there was no adverse outcome such as crown fracture or root fracture,neither filling material falling off in all the 53 patients with 120 teeth.The effect was good and satis-fied.Conclusion The indication should be strictly grasped and then it is convenient to apply glass fiber post com-bined with gingival retraction to treat premolar with severe wedge -shaped defect,and complete coronal restoration should be avoided to reduce the cost of health care.

Resistencia a la fractura de postes de fibra de vidrio vs postes colados en dientes anteriores. Revisión sistemática / Fracture Resistance of fiberglass post vs cast post in anterior teeth. Systematic review

Los dientes anteriores con tratamiento endodóntico y con pérdida de estructura dental usualmente son restaurados con postes de fibra de vidrio o con postes colados, y son susceptibles a presentar fallas que pueden llegar a ocasionar la pérdida dental por no ser rehabilitables. Se propone aquí, identificar cuál entre los dos tipos de postes: prefabricados de fibra de vidrio o postes colados, es más resistente a la fractura debido a las fuerzas biomecánicas compresivas o tensionales que se suceden en los dientes anteriores rehabilitados con coronas respecto a la fractura del poste, de la raíz o el desalojo de este. Se realizó una revisión sistemática de la literatura, con información recolectada desde las bases de datos de los buscadores: PubMed, Scielo, Lilacs y Science Direct. Noventa y tres artículos sobre el tema fueron tamizados según los criterios de selección. Cuatro cumplieron con este procedimiento y se encontró que la resistencia a la fractura tiende a ser mayor en dientes restaurados con postes colados, pero cuando se presenta una fractura es desfavorable para el retratamiento restaurativo. En el caso de los postes de fibra de vidrio se presenta mejor resistencia a la fractura y presentan un patrón por lo general más favorable para un retratamiento en caso de éste fracaso.

Anterior teeth with endodontic treatment and loss of tooth structure are usually restored with glass fiber posts or cast cores, which are susceptible to present failures that may potentially cause tooth loss because they are not able to be restored again. It is proposed here to identify which of the two types of posts: prefabricated fiberglass or cast posts, is more resistant to fracture due to biomechanical forces of compression that occur in the anterior teeth restored with crowns respect to fracture post , root or eviction of this. A systematic review of the literature was conducted with information gathered from the databases of search engines: PubMed, Scielo, Lilacs and Science Direct. Ninety three articles on the topic were screened according to the selection criteria. Four cumplied with this procedure and found that fracture resistance tends to be grater in teeth restored with cast posts, but when a tracture accors is untaorubale for a restorative retreat. In the case of fiberglass posts and greater remaining height structure better fracture resistance is presented, and they present a pattern usually more favorable for retreatment in case of fracture.

Acid Etching and Surface Coating of Glass-Fiber Posts: Bond Strength and Interface Analysis

Abstract The aim of this study was to evaluate the bond strength of a composite resin to glass-fiber post (GFP) treated or not with phosphoric acid, silane coupling agent, and unfilled resin. GFPs were etched or not with 37% phosphoric acid and different surface coating applied: silane coupling agent, unfilled resin, or both. Composite resin blocks were built around a 4-mm height on the GFP. Unfilled resin (20 s) and composite resin (40 s) were light activated by a light-emitting diode unit. The specimens were stored in distilled water at 37 °C for 24 h. Microtensile bond test was performed using a mechanical testing machine until failure (n=10). The data were analyzed using two-way ANOVA followed by Student-Newman-Keuls' test (p<0.05). Failure modes were classified as adhesive, mixed, or cohesive failures. Additional specimens (n=3) were made to analyze the bonded interfaces by scanning electron microscopy. The statistical analysis showed the factor 'surface coating' was significant (p<0.05), whereas the factor 'HP etching' (p=0.131) and interaction between the factors (p=0.171) were not significant. The highest bond strength was found for the silane and unfilled resin group (p<0.05). A predominance of adhesive and cohesive failures was found. Differences regarding the homogeneity and thickness of the unfilled resin layer formed by different GFP surface treatments were observed. The application of silane and unfilled resin can improve the bond strength between GFP and resin composite.

Resumo O objetivo deste estudo foi avaliar o efeito resistência de união de uma resina composta para pinos de fibra de vidro (PFV) tratados ou não com ácido fosfórico, agente de união (silano) e adesivo. PFVs foram condicionados ou não com ácido fosfórico 37% e receberam aplicação de diferentes materiais: um agente de união, um adesivo, ou ambos. Blocos em resina composta foram construídos a 4 mm de altura no PFV. O adesivo (20 s) e a resina composta (40 s) foram fotoativado por um diodo emissor de luz. As amostras foram armazenadas em água destilada a 37 C por 24 h. O teste de microtração foi realizado em uma máquina de ensaio universal (n=10). Os dados foram analisados usando ANOVA dois fatores e teste de Student-Newman-Keuls (p<0,05). Os padrões de fratura foram classificados em falhas adesivas, mistas ou coesivas. Amostras adicionais (n=3) foram feitas para análise da interface de união em microscopia eletrônica de varredura. A análise estatística mostrou que o fator 'recobrimento da superfície' foi significante (p<0,05), enquanto que o fator 'ácido fosfórico' (p=0,131) e a interação entre os fatores (p=0.171) não foram significantes. A maior resistência da união foi encontrada para os grupos silano e adesivo (p<0,05). Uma predominância de falhas adesivas e coesivas foi encontrada. Foram observadas diferenças em relação à homogeneidade e espessura da camada adesiva formada sobre os PFV com os diferentes tratamentos de superfície. Aplicação de silano e adesivo pode melhorar a resistência de união entre PFV e resina composta.

Fracture Resistance of Simulated Immature Teeth after Different Intra-radicular Treatments

The aim of this study was to evaluate the fracture resistance of simulated immature teeth after different intra-radicular treatments. Crowns and roots of bovine incisors were cut transversally and removed to simulate immature teeth. Root canal preparation and flaring were performed using a bur in crown-apex and apex-crown direction. The samples were distributed into 5 groups (n=10): Positive control (PoC) - no root canal flaring or filling; Negative control (NeC) - teeth were sectioned and their root canals were flared; Direct anatomical glass fiber post (RaP) - #2 Reforpost main glass fiber post relined with composite resin; Double tapered conical glass fiber posts (ExP) - #3 Exacto glass fiber post; and #2 Reforpost main glass fiber + Reforpin accessory glass fiber posts (RrP). In RaP, ExP and RrP, 4.0-mm apical plugs were done with MTA Angelus. The specimens were embedded in polystyrene resin inside cylinders and the periodontal ligament was simulated with a polyether-based impression material. The specimens were submitted to compressive fracture strength test (0.5 mm/min at 135° relative to the long axis of the tooth) in a servo-hydraulic mechanical testing machine MTS 810. Data were subjected to one-way ANOVA and Dunnett's C or Tukey's tests (α=0.05). The control groups (PoC and NeC) showed lower fracture strength than the experimental groups. NeC presented the lowest resistance and ExP presented the highest resistance among the experimental groups. The flaring procedures produced a detrimental effect on the fracture resistance of the bovine teeth. Glass fiber intra-radicular posts increased significantly the fracture resistance of simulated immature teeth.

O objetivo deste estudo foi avaliar a resistência à fratura de dentes com rizogênese incompleta simulada após diferentes tratamentos intra-radiculares. A rizogênese incompleta foi simulada pelo seccionamento das coroas e raízes de incisivos bovinos. O preparo e alargamento do canal radicular foram realizados utilizando uma broca no sentido coroa-ápice e ápice-coroa. As amostras foram distribuídas (n=10) em cinco grupos: controle positivo (PoC) - sem preparo do canal radicular e sem obturação; controle negativo (NeC) - os dentes foram seccionados e os canais radiculares foram preparados; pino anatômico direto Reforpost #2 (RaP) - pino de fibra de vidro principal + resina composta; pino de fibra de vidro com dupla conicidade (ExP) - pino de fibra de vidro Exacto #3; e pino de fibra de vidro Reforpost #2 + pinos de fibra de vidro acessórios Reforpin (RrP). Nos grupos RaP, ExP e RrP foram realizados plugs apicais de MTA Angelus com 4,0 mm. As amostras foram incluídas em cilindros com resina de poliestireno e o ligamento periodontal foi simulado com material de moldagem à base de poliéter. As amostras foram submetidas ao teste de resistência à fratura, por meio de força compressiva (0,5 mm/min a 135º em relação ao longo eixo do dente) em uma máquina de ensaios mecânicos MTS 810. Os dados foram submetidos à ANOVA a um critério e aos testes para comparações múltiplas Dunnett C ou Tukey HSD (α=0,05). Os grupos controle (PoC e NeC) apresentaram resistência à fratura inferior aos grupos experimentais, sendo o menor valor médio produzido por NeC. ExP produziu os maiores valores de resistência à fratura entre os grupos experimentais. Os procedimentos de preparo e alargamento produziram efeitos prejudiciais na resistência à fratura de dentes bovinos. A utilização de pinos de fibra de vidro intra-radiculares aumentou significativamente a resistência à fratura de dentes com rizogênese incompleta simulada.

Stress Generated by Customized Glass Fiber Posts and Other Types by Photoelastic Analysis

Endodontic posts are necessary to provide adequate retention and support when no sufficient remaining structure is available to retain the core. There are different materials and techniques to construct post-and-core, but there is no consensus about which one promotes better stress distribution on the remaining tooth structure. This study aimed to quantify and evaluate the distribution of stress in the root produced by customized glass fiber posts compared to different endodontic posts. Twenty-five simulated roots from photoelastic resin were made and divided into 5 groups: CPC, cast post-and-core; SP, screw post; CF, carbon fiber post; GF, glass fiber post; and CGF, customized glass fiber post. After cementing CPC and SP posts with zinc phosphate cement, and CF, GF and CGF posts with resin cement, resin cores were made for groups 2-5. Specimens were evaluated with vertical or 45° oblique loading. To analyze the fringes, the root was divided into 6 parts: palatal cervical, palatal middle, palatal apical, vestibular cervical, vestibular middle, and vestibular apical. The formed fringes were photographed and quantified. Data were recorded and subjected to two-way ANOVA and Tukey's test (5%). SP (1.95±0.60) showed higher stress (p<0.05) compared to the others (CPC-0.52±0.74; CF-0.50±0.75, GF-0.23±0.48 and CGF-0.45±0.83). All posts showed high stress in apical third (CPC-1.40±0.65; SP-2.30±0.44, CF-1.80±0.45, GF-1.20±0.45, CGF-1.70±1.03) Low stress was found in cervical third (CPC-0.20±0.45; CF-0.00±0.00, GF-0.00±0.00, CGF-0.00±0.00), except by SP (1.90±0.65), which showed statistical difference (p<0.05). Customized post showed high stress concentration at the root and conventional glass fiber posts showed more favorable biomechanical behavior.

Pinos endodônticos são necessários para promover retenção e suporte adequados quando a estrutura dental remanescente não é suficiente para reter o núcleo. Há diferentes materiais e técnicas para construir o núcleo, mas não há consenso sobre o qual promove a melhor distribuição de tensão na estrutura dental remanescente. O objetivo deste trabalho foi quantificar e avaliar a distribuição de tensões produzidas nas raízes por pinos de fibra de vidro customizados quando comparados a diferentes pinos endodônticos. Vinte e cinco raízes simuladas em resina fotoelástica foram confeccionadas e divididas em 5 grupos: CPC, núcleo metálico fundido, SP, pino rosqueável; CF, pino de fibra de carbono; GF, pino de fibra de vidro; CGF, pino de fibra de vidro customizado. Depois da cimentação dos pinos de CPC e SP com cimento de fosfato de zinco e dos pinos de CF, GF e CGF com cimento resinoso, núcleos em resina foram feitos para os grupos 2-5. Os espécimes foram avaliados com carga vertical ou oblíqua a 45o. Para analisar as franjas, a área da raiz foi dividida em 6 partes: palatina cervical, palatina média, palatina apical, vestibular cervical, vestibular média e vestibular apical. As franjas formadas foram fotografadas e quantificadas. Os dados foram gravados e submetidos à ANOVA de dois fatores e ao teste de Tukey (5%). SP (1,95±0,60) mostrou maior tensão (p<0,05) quando comparado com os demais (CPC - 0,52±0,74; CF - 0,50±0,75, GF - 0,23±0,48, CGF - 0,45±0,83). Todos os pinos mostraram maior tensão no terço apical (CPC - 1,40±0,65; SP - 2,30±0,44, CF - 1,80±0,45, GF - 1,20±0,45, CGF - 1,70±1,03) Menor tensão foi encontrado no terço cervical (CPC - 0,20±0.45; CF - 0,00±0 00, GF - 0 ,0±0,00, CGF - 0,00±0,00), exceto pelo SP (1,90±0,65), que não apresentou diferença estatística (p<0,05). Pinos customizados de fibra de vidro mostraram maior concentração de estresse na raiz quando comparados com pinos convencionais de fibra de vidro, que se mostraram com comportamento biomecânico mais favorável.

Dental root canal nail light cure resin and fiber post and resin core Comparison of clinical application of residual root and crown restoration / 安徽医科大学学报

From January,2011 to December,2013,103 cases were selected from patients whose residual roots and crowns were restored by porcelain fusedto metal crowns after post core crown restorations.Patients were fully in-formed and randomly divided into two groups,including 51 cases receiving the post core restoration with dental root canal nail,52 cases being repaired with glass fiber post core restoration.After 6 ~12 months of follow-up observa-tion,in the group having received post core restoration with the dental root canal nail,there were 2 cases of crown root fracture,4 cases of falling off,the success rate was 88.24% (45 /51).In the group of fiber post and core res-toration,there was 1 case of crown root fracture,1 case of falling off;the success rate was 96.15% (50 /52).The restoration of fiber post core and porcelain fused to metal crown is the best choice of restoration of residual crown and root,but the root canal nail of teeth with light cured resin core is more economical,simple,easy to operate, and suitable for basic use.

Clinical assessment of repair of free second molar residual crowns by glass fiber post and resin core / 实用口腔医学杂志

37 free second molar residual crowns were repaired by glass fiber post and resin core(GF group),and another 37 by cobalt chromium alloy casting post and core(CCA group).The success rate of 1 ~5 years of GF group was 1 00%,1 00%,91 .9%,86.5% and 81 .1 %;that of CCA group 97.3%,91 .9%,83.8%,81 .1 % and 73.0%,respectively(P >0.05).

Canal Preparation and Filling Techniques do not Influence the Fracture Resistance of Extensively Damaged Teeth

The purpose of this study was to assess the fracture resistance of extensively damaged teeth after two root canal preparation techniques (hand and rotary files) and after two filling techniques (active and passive compaction). Sixty-eight maxillary canines roots with an apical diameter equal to that of a #25 K-file were embedded in acrylic resin and the periodontal ligament was simulated by using a polyether impression material. The roots were randomly distributed into four groups (n=17): hand preparation and active compaction (HA), hand preparation and passive compaction (HP), rotary preparation and active compaction (RA), and rotary preparation and passive compaction (RP). All roots were restored with glass fiber post and metallic crown. The specimens were mechanically cycled (500,000 cycles, 45°, 37°C, 133 N, 2 Hz) and then subjected to a fracture resistance test. A single blinded examiner analyzed the external root surface and classified the failure pattern as favorable or unfavorable. The fracture resistance values ranged between 621.15 N (HP) and 785.71 N (HA). However, the Kruskal-Wallis test did not reveal differences in the fracture resistance values among the four groups (p =0.247). Under the tested conditions, root canal preparation and filling techniques had no influence on the fracture resistance of extensively damaged teeth restored with fiber post and metallic crown.

O objetivo deste estudo foi avaliar a resistência à fratura de dentes amplamente destruídos após duas técnicas de preparo (limas manual e rotatória) e após duas técnicas obturadoras (compactação ativa e passiva). Sessenta e oito raízes de caninos superiores com diâmetro apical igual a uma lima K #25 foram embutidas em resina acrílica e o ligamento periodontal foi simulado utilizando um material de moldagem à base de poliéter. As raízes foram distribuídas aleatoriamente em quatro grupos (n=17): preparo manual e compactação ativa (MA), preparo manual e compactação passiva (MP), preparo rotatório e compactação ativa (RA) e preparo rotatório e compactação passiva (RP). Todas as raízes foram restauradas com pino de fibra de vidro e coroa metálica. Os espécimes foram ciclados mecanicamente (500.000 ciclos, 45°, 37°C, 133 N, 2 Hz) e depois submetidos ao teste de resistência à fratura. Um único examinador cego analisou a superfície externa das raízes e classificou o padrão de falha em favorável ou desfavorável. Os valores de resistência à fratura variaram entre 621,15 N (MP) e 785,71 N (MA). Entretanto, o teste de Kruskal-Wallis não revelou diferença nos valores de resistência à fratura entre os quatro grupos (p=0,247). Diante das condições testadas, as técnicas de preparo e de obturação do canal radicular não influenciam na resistência à fratura de dentes amplamente destruídos restaurados com pino de fibra de vidro e coroa metálica.

Effects of Fiber Length and Content of Glass Fiber Posts on the Fracture Resistance of Teeth / 天津医药

Objective To explore the influence of different lengths and contents of glass-fiber post on the fracture resistance of teeth, and to investigate the optimal length and content of glass-fiber post used for restorative treatment. Meth-ods Forty-two intact single canal mandibular premolars were collected from orthodontic patients and were divided into three experimental groups (A, B and C). All the teeth were endodontically treated after cut off the crowns from the 2 mm above cemento-enamel junction. The post lengths were10 mm in A group, 8 mm in B group, and 6 mm in C group.There were two subgroups for each experimental group (A1, A2, B1, B2, C1, C2 ), 7 teeth for each subgroup.The 42%glass fiber post was used in A1, B1 and C1 groups. The 75%glass fiber post was used in A2, B2 and C2 groups. All of groups were restored with resin cores and metal crowns. The fracture resistance was measured with universal testing machine and recorded the root frac-ture pressure data and the mode of all the teeth. Results The fracture resistance was significantly higher in group A than that of group B and group C (P<0.05), and the fracture resistance was significantly higher in group B than that of group C (P<0.05). The fracture resistance was significantly higher for 75%glass fiber post than that of 42%glass fiber post (P<0.05). Conclusion Within a certain range, the longer the length of glass fiber post, the greater the tooth fracture resistance. The fracture resistance of fiber content is better for 75%glass fiber post than that of 42%glass fiber post.

Glass fiber post versus metal post in the restoration of endodontically treated teeth / 中国组织工程研究

BACKGROUND:The post and core system for residual roots and crowns can achieve satisfactory effects, when fil ing restoration, ful crowns or inlay has poor effects. OBJECTIVE:To evaluate the clinical use of glass fiber post and metal post in the restoration of endodontical y treated teeth. METHODS:A total of 106 patients with 160 endodontical y treated teeth were selected and restored with glass fiber post (n=80 teeth) and metal post (n=80 teeth) fol owed by porcelain-fused-mental crown. The restorations were evaluated clinical y for 9 to 33 months. RESULTS AND CONCLUSION:Glass fiber post treatment for 78 teeth was effective and that for two teeth were failed, with a successful rate of 98%. Metal post restoration was effective in 71 teeth and failed in nine teeth including one tooth of crown fracture, four of root fracture and four of post loss, with a successful rate of 89%. There was statistical y significant difference between two groups (P<0.05). Glass fiber post is better in convenient handling and good color and reduced probability leading to root broken for dental restoration compared with metal post.

Evaluation of push-out bond strength of surface treatments of two esthetic posts.

Objectives: To evaluate the push-out bond strength of two surface treatments of a glass fiber and zirconia ceramic post. Materials and Methods: Sixty samples were fabricated and divided into two main groups according to the type of esthetic post indicated for maxillary central incisor: glass fiber post and zirconia ceramic post. Each group was subdivided to two subgroups according to the type of bond strength test either between post and root or between post and core. Each subgroup was further subdivided into three classes according to surface treatment: no treatment (control), sandblasting in conjunction with silica particles then silane coating (SB+SIC+SC), etching using hydrofluoric acid then silane coating (E+SC). For the subgroups of the bond strength between post and root, each class was subdivided into two subclasses according to the location of the sample (cervical or apical). Results: Bond strength to root canal or resin core were affected by the type of post, glass fiber post recorded significant higher bond strength than zirconia ceramic. Surface treatment recorded higher values for bond strength, SB+SIC+SC gave higher bond strength than E+SC. Cervical section recorded significant higher bond strength than apical section. Conclusions: Glass fiber posts recorded higher bond strength than glass ceramic post to both root canal and resin core. Surface treatments increase bond strength for glass fiber and zirconia ceramic posts to both root canal and resin core. SB+SIC+SC gave higher bond strength than E+SC. Bond strength at the cervical section is higher than at the apical section.

Influence of modification in core building procedure on fracture strength and failure patterns of premolars restored with fiber post and composite core

PURPOSE: The influence of the modified process in the fiber-reinforced post and resin core foundation treatment on the fracture resistance and failure pattern of premolar was tested in this study. MATERIALS AND METHODS: Thirty-six human mandibular premolars were divided into 4 groups (n = 9). In group DCT, the quartz fibre post (D.T. Light-post) was cemented with resin cement (DUO-LINK) and a core foundation was formed with composite resin (LIGHT-CORE). In group DMO and DMT, resin cement (DUO-LINK) was used for post (D.T. Light-post) cementation and core foundation; in group DMO, these procedures were performed simultaneously in one step, while DMT group was accomplished in separated two steps. In group LCT, the glass fiber post (LuxaPost) cementation and core foundation was accomplished with composite resin (LuxaCore-Dual) in separated procedures. Tooth were prepared with 2 mm ferrule and restored with nickel-chromium crowns. A static loading test was carried out and loads were applied to the buccal surface of the buccal cusp at a 45 degree inclination to the long axis of the tooth until failure occurred. The data were analyzed with MANOVA (alpha = .05). The failure pattern was observed and classified as either favorable (allowing repair) or unfavorable (not allowing repair). RESULTS: The mean fracture strength was highest in group DCT followed in descending order by groups DMO, DMT, and LCT. However, there were no significant differences in fracture strength between the groups. A higher prevalence of favorable fractures was detected in group DMT but there were no significant differences between the groups. CONCLUSION: The change of post or core foundation method does not appear to influence the fracture strength and failure patterns.