Influência de primers dentinários modificados por digluconato de clorexidina na resistência de união de pinos de fibra de vidro em dentina radicular / Influence of modified dentin primers containing chlorexidine digluconate on bond strenght of glass-fiber posts to radicular dentin

O estudo avaliou in vitro o efeito da modificação de primers dentinários com digluconato de clorexidina na resistência de união de pinos de fibra de vidro em dentina radicular. A hipótese testada considerou que a incorporação de clorexidina em primers dentinários não interferiria na resistência de união de pinos de fibra de vidro independentemente da profundidade da dentina radicular testada imediatamente e após envelhecimento. Sessenta raízes retilíneas bovinas foram selecionadas e divididas aleatoriamente em 6 grupos (n=10). As raízes foram obturadas e os condutos preparados de modo sequencial e padronizado para receber os pinos de fibra de vidro que foram silanizados previamente. A dentina radicular foi condicionada com ácido fosfórico 37% por 15s, seguido da aplicação do primer do sistema adesivo convencional ou primer modificado, seguido da aplicação do adesivo dentinário. Os primers experimentais foram preparados, incorporando solução aquosa ou alcóolica de clorexidina com concentração de 0,12%. O cimento resinoso dual foi inserido no interior das raízes e os pinos posicionados para fotoativação durante 40s. Para determinar a resistência de união, metade das amostras foram cortadas transversalmente em 3 secções em diferentes profundidades da dentina radicular, e testadas imediatamente por push-out, em uma máquina de ensaios universal (EMIC), com célula de carga de 100Kgf e velocidade de 1mm/min. A outra metade das amostras receberam reconstrução coronária com resina com...

Abstract: The present in vitro study evaluated the influence of modified dentin primers containing chlorhexidine digluconate on bond strength of glass fiber posts to radicular dentin. The hypothesis to be tested considers that the incorporation of chlorexidine in dentin primers does not interfere on the bond strength of glass fiber posts independently of the analyzed radicular dentin depth tested immediately or after thermocycling aging. Sixty rectilinear bovine roots were selected and randomly distributed into 6 groups (n=10). The endodontically treated root canals were sequentially and standardized prepared for glass-fiber posts insertion, which were previously silanized. The radicular dentin was etched with 37% phosphoric acid for 15s and conditioned using the conventional primer or the modified primer followed by the corresponding adhesive. Experimental primers were prepared by adding aqueous or alcoholic solutions of chlorexidine to obtain a 0.12% concentration. A dual- cured resin cement was inserted into the root canals and the posts were positioned for light polymerization for 40s.To measure the bond strength, half of the samples were transversally sectioned into 3 slices from different radicular regions, and immediately processed for push-out test into an universal test machine (EMIC), with a load-cell of 100Kgf, and at a speed of 1mm/min. The other half a coronary reconstruction was conducted with composite resin, based on a standardized silicon matrix. The periodontal ligame...

A root canal filling per se does not have a significant negative effect on the marginal periodontium.

AIM: To evaluate the periodontal status of single-rooted endodontically treated teeth (ET), correcting for patient- and tooth-related factors. METHODS: Clinical parameters (BoP,PD,CAL) of 240 ET and 240 contralateral vital teeth (VT), before and after non-surgical periodontal treatment, were extracted retrospectively from the journals of 175 patients. Possible patient-related (age, gender, smoking status) and tooth-related (interproximal restoration, root canal filling's extent, post, tooth type) confounders were tested. RESULTS: At baseline, frequency of BoP at an interproximal site at ET versus VT was 70.4% versus 65.0%, respectively. The frequency of teeth with interproximal PD ≥ 5 mm and CAL ≥ 5 mm was 47.9% versus 42.9% and 54.6% versus 49.6% at ET and VT, respectively. Interproximal PD and CAL at ET versus VT were 3.86 versus 3.61 mm and 4.11 versus 3.95 mm. After correcting for tooth-related factors, no significant differences were observed between ET and VT. An improper restoration had a significant (p < 0.001) negative effect on BoP [OR 3.49 (95%CI: 1.95-6.27)], PD [36.81% (95%CI: 18.52-57.92)] and CAL [27.01% (95%CI: 12.67-43.18)]. No significant differences between ET and VT were observed regarding clinical outcome of non-surgical periodontal therapy. CONCLUSIONS: Presence of a root canal filling per se does not have a significant negative influence on the marginal periodontium, when correcting for the quality of the interproximal restoration.

Posts--when it all goes wrong! Part 1: case assessment and management options.

UNLABELLED: Posts have been used for many years to retain restorations or cores for extra-coronal restorations in endodontically treated teeth.This article discusses the variety of post systems that are available and the incidence and reasons for failure of teeth that have been restored with posts. The treatment options available for the management of such failures are considered, in addition to the indications for both non-surgical and surgical management of endodontic failures. The attitudes of dentists and the perceived complications of attempting post removal are reviewed, along with the evidence to support the prevalence of complications. CLINICAL RELEVANCE: Failure of post-retained restorations is a relatively frequent finding due to failure of the restoration itself or the endodontic treatment. It is therefore important to understand and be aware of the various treatment options available, their indications and associated risks.

Criterios para la selección de postes de base orgánica reforzados con fibras (PBORF) / Criteria for the selection of fiber-reinforced posts (PBORF)

Los postes de base orgánica reforzados con fibras son protagonistas en la rehabilitación posendodóntica contemporánea. Sin embargo, en la actualidad, coexisten en el mercado postes que ofrecen características físicas y ópticas muy diferentes y que pueden generar distintos pronósticos en la rehabilitación. Este artículo presenta los criterios más importantes para seleccionar PBORF que ofrezcan adecuados rendimientos físicos, estéticos y que impliquen una técnica clínica con mayor seguridad para el proceso de rehabilitación.

Esthetic and functional consideration in restoring endodontically treated teeth.

The selection of the best restoration for an endodontically treated tooth in the aesthetic zone depends on strength and the ability to recreate the form, function, and aesthetics of the natural tooth. The increased use of all-ceramic materials is a result of improved ceramic materials and adhesive systems. However, the advent of the current variety of translucent ceramic systems makes the shade of the abutment important in achieving the desired aesthetic outcome. This article discusses the different types of posts used in the restoration.

Avaliação do desempenho de retentores intra-radiculares pré-fabricados em dentes tratados endodonticamente

Sempre que o dente é submetido a um tratamento endodôntico, ocorre a diminuição da sua resistência, em razão do desgaste excessivo do remanescente coronário e radicular. Muitas vezes, estes dentes requerem, em muitos casos, restaurações diretas ou indiretas associadas a pinos intra-radiculares pré-fabricados com o intuito de restabelecer forma e função do elemento propriamente dito...

Static and fatigue fracture resistances of pulpless teeth restored with post-cores.

OBJECTIVES: Superior restorative methods for effectively strengthening pulpless teeth need to be identified, since vertical root fractures of pulpless teeth are still a major problem in everyday clinical practice. The present study tested the null hypothesis that there were no differences in static and fatigue fracture resistances of pulpless teeth restored with different types of post-core systems. METHODS: Extracted human premolars were restored with a combination of either a fiber post or metallic post and a composite resin core. Teeth with full crown preparations without post-core restorations served as a control. A 90 degrees vertical or 45 degrees oblique static compressive load was applied to restored teeth, and fracture loads and modes of fracture were recorded. Fatigue fracture tests were conducted by applying sinusoidal cyclic loads to restored teeth from vertical or oblique directions. Fatigue limits for each restoration were calculated using the staircase approach. RESULTS: In both static and fatigue fracture testing under vertical or oblique loadings, the fracture loads of teeth restored with fiber posts were significantly greater than those of teeth restored with metallic posts. The fatigue limits of teeth restored with fiber and metallic posts were 112 kgf and 82 kgf respectively under vertical loadings and 26 kgf and 20 kgf under oblique loadings. SIGNIFICANCE: The combination of a fiber post and a composite resin core showed superior fracture resistance against both static and fatigue loadings compared to restorations using a metallic post, and is therefore recommended in restoring pulpless teeth.

Analysis of dentinal stress distribution of maxillary central incisors subjected to various post-and-core applications.

This study evaluated the stress distribution on an endodontically treated maxillary central incisor restored with different post-and-core systems by using a three-dimensional finite element analysis model. Seven three-dimensional finite element models were created. Each model contained cortical bone, cancelous bone, periodontal ligament, 3 mm apical root canal filling, post-and-core and all-ceramic crowns. Two different pre-fabricated zirconia ceramic post systems, a glass fiber-reinforced post system and a titanium post system were modeled. As a control, an all-ceramic crown on an endodontically treated maxillary central incisor without a post-and-core was modeled. Each model received a 45 degrees oblique occlusal load at a constant intensity of 100 N. In each model, the ratio of Von Mises stress distribution was compared. The greatest stresses were observed in the coronal third of the roots on facial surfaces. The ratio of Von Mises stress distribution in dentin for the zirconia ceramic post (CosmoPost) and ceramic core (Cosmo Ingot), zirconia ceramic post (CosmoPost) and composite core (Tetric Ceram), glass fiber-reinforced post (FRC Postec) and composite core (Tetric Ceram), titanium post (Er post) and composite core (Tetric Ceram), zirconia ceramic post (Cerapost) and ceramic core (Cosmo Ingot), zirconia ceramic post (Cerapost) and composite core (Tetric Ceram) and the control group were 0.886, 0.889, 0.988, 0.924, 0.889, 0.893 and 1, respectively. The stress concentrations in dentin created by two different zirconia ceramic post systems were nearly the same. The zirconia ceramic post systems created slightly less stress concentration in dentin than the glass fiber-reinforced and titanium posts.

Pinos de fibra: escolha corretamente / Fiber post: choose correctly

Existem situações clínicas em que um elemento dental tratado endodonticamente requer o uso de um retentor intracanal. A evolução científica trouxe, além dos núcleos metálicos, os pinos de fibra como uma alternativa promissora e a última evolução nesse campo. A necessidade de acompanhar conceitos de estética, a possibilidade de reconstrução do elemento dental de forma mais natural, o baixo custo, a facilidade da técnica e a fácil obtenção comercial são alguns dos fatores que fazem a escolha recair sobre os pinos de fibra, os quais oferecem também resiliência e são altamente retentivos, apresentando adesão ininterrupta entre dente e sistema pino e núcleo. Porém, a rápida evolução desses sistemas dificulta muitas vezes a escolha correta do sistema de pinos. Este trabalho se propões a fazer uma revisão da literatura sobre os pinos de fibra, suas indicações, vantagens e desvantagens

Direct core materials.

There are many materials that can be used for direct-placement cores. Although the scientific evidence is incomplete, some materials are better suited to this task than others. This article provides an overview of direct-placement core materials and highlights what clinicians should consider when assessing a new product.

Nuevos enfoques en la reconstrucción coronaria del diente endodónticamente tratado (DET) / New approaches in the coronal reconstruction of the endodontically treated tooth (ETT)

Los conceptos referidos a la rehabilitación del diente endodónticamente tratado han cambiado sustancialmente. Se acepta como verdadero refuerzo a la misma estructura dentaria, por lo tanto, los procedimientos que la conserven son de elección. Asimismo, se deben diferenciar las situaciones en el sector anterior y posterior de la arcada dentaria, siendo necesaria en el sector anterior una estabilización mecánica con pernos o potes. Será en cambio, más habitual no utilizar dipositivos intrarradiculares en el sector posterior. La integración de superficies que se consigue con los mecanismos adhesivos, permite más ahorro de tejidos. En tanto que las restauraciones (inlays, onlays, coronas y postes no metálicos) elaboradas con materiales más fácilmente integrables (cerámicos y compuestos) cobran mayor importancia en relación con esta filosofía

Survival rate and fracture strength of incisors restored with different post and core systems and endodontically treated incisors without coronoradicular reinforcement.

This in vitro study evaluated the survival rate and fracture resistance of maxillary central incisors restored with different post and core systems. The post and core systems investigated were a prefabricated high precious metal post with cast core (group A), zirconia post with a prefabricated bonded ceramic core (group B), and a resin-ceramic interpenetrating phase composite post (experimental) with a prefabricated bonded ceramic core (group C). The all-ceramic copings were cemented using Panavia 21 TC. In the group without coronoradicular reinforcement, the access cavity was closed with a light-cured composite in combination with a dentine-bonding agent (group D). Each specimen was intermittently loaded and thermocycled before final stress tests in a Zwick machine. The survival rates after 1,200,000 cycles in the artificial mouth were 90% (group A), 80% (group B), 60% (group C), and 100% (group D). Statistically significant differences were found between all groups with the exception of A and B, when failure during cyclic loading was included (Kruskal-Wallis multiple comparisons test). Samples restored with a cast post and core demonstrated more vertical root fractures. It was concluded that the preservation of both internal and external tooth structure is of utmost importance when restoring endodontically treated teeth.

Pernos preformados ¿por qué resistirse? / Prefabricated posts, why to resist?

Los sistemas de pernos preformados para la reconstrucción de elementos tratados endodónticamente son variados y pueden aplicarse a distintas situaciones clínicas. Estos pernos preformados pueden ser de estructura metálica o libres de metal. Estos últimos pueden ser utilizados en restauraciones que tienen alto requerimiento estético como las cerámicas puras. Para lograr el éxito clínico utilizando algunos de estos sistemas es necesario seguir las indicaciones precisas que cada sistema propone

Uso y abuso de los postes: una revisión de la literatura / Use and abuse of posts: a review of the literature

El poste debe emplearse solamente cuando no haya estructura dental remanente suficiente para darle retencion a la restauración, ya que el único propósito de restaurar una pieza con un poste es el de crear una subestructura en la que se pueda detener una restauración final. La idea de que un poste refuerza la estructura remanente de un órgano dentario debe desecharse, ya que en la mayoría de los casos, la colocación de un poste favorece la debilitación del órgano dentario. Es importante revisar los parámetros para la preparación y colocación de postes, para que tanto el tratamiento endodóntico como la restauración final sean exitosos

Direct cores for vital teeth--materials and methods used to retain cores in vital teeth.

A core, or foundation restoration, is used to restore extensively damaged teeth to a form suitable for crown preparation. This literature review considers the range of materials which can be used for cores and the evidence for their suitability. The methods for their retention in vital teeth will be presented and appraised.

In vitro comparison of the fracture resistance and failure mode of fiber, ceramic, and conventional post systems at various stages of restoration.

PURPOSE: This in vitro study evaluated 6 post systems over 4 simulated clinical stages of tooth restoration to (1) determine quantitatively the fracture resistance strength at each stage when a static loading force is applied to cause failure; (2) determine the failure mode for each post system at each simulated clinical stage; and (3) determine the feasibility of removing failed post systems. MATERIALS AND METHODS: Ten post systems made with various materials and designs were tested at the following 4 stages of simulated clinical treatment: stage #1: posts only, loaded using a 3-point loading model to failure, to determine transverse strengths and failure modes for each post system; stage #2: posts alone, bonded into teeth; stage #3: posts bonded into teeth with core build up; stage #4: post and core build up and full veneer restoration. For stages #2 through #4, the coronal portion of 60 mandibular premolars was amputated at the cemento-enamel junction, the canals were treated endodontically, and the specimens were mounted in acrylic blocks. A testing force was applied to the posts at 90 degrees to the long axis of the tooth, 4 mm from the cemento-enamel junction. The O'Brien test for constant variance was performed over the treatment groups. For nonconstant variance, the Welsh analysis of variance was used to test for equalities of treatment means. The Tukey Kramer procedure determined which treatment procedures differed. RESULTS: The failure thresholds for each post system were significantly different at each stage of testing, but the order of test results by post type remained generally consistent from one stage to the next. ParaPosts (Coltene, Whaledent Int, New York, NY) and core build up resulted in significantly higher failure thresholds through all 4 stages of testing. This post system also consistently displayed a high number of nonfavorable tooth fractures. FibreKor post and cores (Jeneric Pentron Inc, Wallingford, CT) resulted in significantly lower failure threshold values in stages #2 through #4. This post system displayed no tooth fractures in stages #2 and #3 and a similar number of nonfavorable tooth fractures in stage #4 when compared with the other systems. C-Post (Bisco Dental Products, Schaumburg, IL), CosmoPost (Ivoclar Vivadent North America Inc, Amherst, NY), and AesthetiPost (Bisco Dental Products) grouped in descending order through stages #2 to #4. These systems displayed intermediate fracture resistance strengths, as well as a moderate number of nonfavorable tooth fractures. CosmoPost exhibited a significant number of brittle post fractures with fragments left in the root canal at all stages. The fracture resistance of the cast metal post varied from stage to stage. No teeth fractured at stage #2. At stage #3, 9 of 10 teeth fractured nonfavorably, and all teeth fractured nonfavorably in stage #4. CONCLUSIONS: The fiber posts evaluated provided an advantage over a conventional post that showed a higher number of irretrievable post and unrestorable root fractures. At the stage of final restoration insertion, there was no difference in force to failure for all but the FibreKor material, which continued to be weaker than all other tested materials. The fiber posts were readily retrievable after failure, whereas the remaining post systems tested were nonretrievable. J Prosthodont 2001;10:26-36.

Postes flexibles de fibra de vidrio (técnica directa) para restauración de dientes tratados endodónticamente / Glass fiber flexible posts (direct technique) for restoration of endodontically treated teeth

Se presentan los principios en la restauración de dientes tratados endodónticamente con el uso de postes flexibles de fibra de vidrio. Características de los postes y su racionalización de uso. Se presenta una descripción detallada de la secuencia clínica con el uso de diversos materiales

Posts and cores: when to use them.

The two overriding factors for successful post restoration are: 1. Retention, i.e., resistance to torsional forces. Published research is clear that threaded posts are the method of choice for the restoration of endodontically treated teeth in order to achieve optimal success. Prethreaded and self-threaded are the two systems from which to choose. The words active and passive should be applied to the method of producing threads, not the posts. The most gentle way to produce a thread is with a thread cutter. 2. Stress distribution of some cylindrical threaded posts has been shown to be far superior to nonthreaded cylindrical and nonthreaded tapered posts. With the acceptance of threaded, cylindrical prefabricated posts, new terminology has evolved, and the use and meaning of these words has been made more precise.

Pernos de última generacióm para coronas cerámicas libres de metal / Post-system of last generation for ceramic crowns free-metal

Different systems are used too rebuilt teeth on ceramics crowns, and tjhey are available to differents clinical and professional situations. All of them provide the necessary principles to obtain acceptable clinical results. These "post-systems" may recreate the integrity of a teeth, withouht representing a problem of translucency to all ceramics crowns. The future dentistry concept, reffering to free-metal prosthodontics restaurations, find many types of validations in these "post-systems". It is very important for the clinician to know the existence of such possibilities of different variances with a certain clinic validation, in order to incorporate them to daily practice. The purpose of this work is to present general concepts about the different postrestauration systems for use on all ceramics crowns