Application of polymeric porcelain color-masking cast posts in the aesthetic repair of anterior teeth: a case report / 华西口腔医学杂志

Many patients with large-area tooth defect need cast post-core crown restoration. However, the color defect of the cast post-core will affect the final restorative result, especially that of the anterior teeth. A new technology of color masking by applying CERAMAGE polymeric porcelain to the cast metal post-core surface improves the color of a full-ceramic restoration of anterior teeth and may provide a new alternative for the aesthetic repair of anterior teeth with a large area of defective tooth.

Fracture resistance of upper central incisors restored with different posts and cores

OBJECTIVES: To determine and compare the fracture resistance of endodontically treated maxillary central incisors restored with different posts and cores. MATERIALS AND METHODS: Forty-eight upper central incisors were randomly divided into four groups: cast post and core (group 1), fiber-reinforced composite (FRC) post and composite core (group 2), composite post and core (group 3), and controls (group 4). Mesio-distal and bucco-lingual dimensions at 7 and 14 mm from the apex were compared to ensure standardization among the groups. Twelve teeth were prepared for crown restoration (group 4). Teeth in other groups were endodontically treated, decoronated at 14 mm from the apex, and prepared for posts and cores. Resin-based materials were used for cementation in groups 1 and 2. In group 3, composite was used directly to fill the post space and for core build-up. All samples were restored by standard metal crowns using glass ionomer cement, mounted at 135degrees vertical angle, subjected to thermomechanical aging, and then fractured using a universal testing machine. Kruskal-Wallis and Mann-Whitney U tests were used to analyze the data. RESULTS: Fracture resistance of the groups was as follows: Control (group 4) > cast post and core (group 1) > fiber post and composite core (group 2) > composite post and core (group 3). All samples in groups 2 and 3 fractured in restorable patterns, whereas most (58%) in group 1 were non-restorable. CONCLUSIONS: Within the limitations of this study, FRC posts showed acceptable fracture resistance with favorable fracture patterns for reconstruction of upper central incisors.

Root Dentin Strain and Temperature Rise During Endodontic Treatment and Post Rehabilitation

This study investigated the effects of endodontic treatment procedures and different post systems rehabilitation steps on the strain and temperature rise on apical and cervical root dentin regions. Twenty-one extracted human canine teeth had two strain gages attached to the distal root surface and two thermocouples attached to the mesial root surface (cervical and apical). The strain and temperature rise were recorded during the following procedures: root canal preparation, final rinse and drying, root canal filling and canal relief. Then the teeth were divided into three groups (n=7), according to the type of post system: CPC, cast post and core; FGP, fiberglass post; and PSP, prefabricated steel post. Data continued to be recorded during the post space preparation, post modeling (only for CPC), post trying and post cementation. Data were subjected to a two-way ANOVA followed by Tukey's test (α=0.05). The post-space preparation caused the highest temperature rise (4.0-14.9 °C) and the highest strain in the apical region during irrespective of post type. The resin cement light-activation resulted in significant temperature increases in the cervical region for all of the groups. The canal relief and the post-space preparation produced highest temperature rises. The CPC post modeling resulted in higher root strain level similarly the level of post preparation. The PSP resulted in highest strain during post trying and post cementation.

Este estudo investigou os efeitos de diferentes etapas do tratamento endodôntico e da inserção de diferentes tipos de retentores na deformação e aumento de temperatura na dentina radicular apical e cervical. Vinte e um dentes caninos humanos extraídos tiveram dois extensômetros colados à superfície da raiz distal e dois termopares ligados à superfície da raiz mesial (cervical e apical). A deformação e aumento de temperatura foram registrados durante os seguintes procedimentos: preparo do canal radicular, irrigação final e secagem, obturação do canal, alívio do canal; em seguida, os dentes foram divididos em três grupos (CPC, núcleo moldado e fundido; FGP, pino de fibra de vidro, e PSP pino pré-fabricado em aço-inoxidável, n=7). Os dados foram continuamente mensurados durante a modelagem do núcleo (somente para o CPC), inserção e cimentação dos retentores. Os dados foram submetidos a análise de variância fatorial, seguido pelo teste de Tukey (α=0,05). O preparo do canal para o retentor causou o maior aumento de temperatura (4,0-14,9 °C) e maior deformação na região apical independente do tipo de retentor. A ativação com luz resultou em significativo aumento de temperatura na região cervical, para todos os grupos. O alívio do canal e o preparo para o pino produziram maiores aumentos de temperatura. A modelagem do CPC resultou em maior nível de deformação da raiz em nível similar ao preparo para o retentor. O PSP resultou em maior deformação durante a inserção e ao final da cimentação.

Evaluación no lineal de dos postes diferentes / Nonlinear evaluation of two different posts

Introducción: los dientes tratados endodóncicamente que van a ser rehabilitados con coronas y que han perdido parte de su estructura dental, necesitan de un poste prefabricado o colado para que ayude a la retención de la restauración final y así el diente puedarecuperar la funcionalidad y la estética. La literatura reporta cuándo utilizar un poste colado o prefabricado, pero no es contundente cuál distribuye mejor los esfuerzos, cuál material o forma de poste es mejor y si el módulo de elasticidad tiene o no relación con la distribución de las cargas a lo largo del eje axial del diente. Métodos: se hicieron dos modelos en SolidWorks de un incisivo central superior con todassus estructuras de soporte, uno con un poste colado y otro con un poste prefabricado, además de una corona completamente cerámica. Mediante un análisis de elementos finitos se cargaron dichos dientes a 200, 400, 600 y 800 N para llevarlos hasta la plasticidad. Resultados: 200 y 400 N ambos postes mostraron diferente distribución de esfuerzos sin afectar la restauración o la raíz dental. Conclusiones: a cargas masticatorias normales, ambos postes son predecibles para rehabilitar un diente que necesita de la incorporación de un poste.

Introduction: endodontically treated teeth that will be restored with crowns and which have lost part of their dental structure need a cast post or a prefabricated post to improve final restoration retention and therefore to be able to regain their functionality andaesthetics. The literature suggests when to use a cast or prefabricated post, but it is not conclusive in terms of which one has a better stress distribution, which post material or shape is better, or whether their modulus of elasticity is related to load distribution along thetooth’s axis. Methods: by using Solid Works, two models of a maxillary central incisor with all its supporting structures were made, one with a cast post and another one with a prefabricated post plus an all-ceramic crown. By means of finite element analysis both teeth were subjected to loads of 200, 400, 600 and 800 N up to reaching their plasticity. Results: at 200 and 400 N, both posts showed different stress distribution patterns without altering the restoration or the tooth’s root. Conclusions: at normal masticatory loads, both posts are likely to restore a tooth that needs addition of a post.

Longitudinal clinical evaluation of post systems: a literature review

In this survey, retrospective and prospective clinical studies dealing with cast-post-and core and fiber posts were reviewed regarding the rate of survival of restorations and the most prevalent failures. Electronic searches of the literature were performed in MEDLINE by crossing the key words: "Fiber post and clinical study", "Fiber post and clinical evaluation", "Cast post-and-core and clinical study", and "Root post and retrospective survival study". The cut-off dates were December 1990 through the end of December 2010. Review of literature showed that several interrelated biological, mechanical, and aesthetic factors are involved in the survival rate of restorative procedures in endodontically treated teeth, and post selection should fulfill and optimize these factors. Data based on long-term clinical studies are essential for the general practitioner when making clinical decisions. An adequate selection of teeth and post system must be made, and a minimal amount of existing tooth substance should be removed. A ferrule must be present for safe indication of the fiber posts. Fiber glass posts have demonstrated good survival in clinical studies, with similar performance to cast-post-and cores. Metallic posts have good clinical survival, but the associated failures are mostly irreversible, unlike what happens with the glass fiber posts.

O objetivo foi realizar revisão de estudos clínicos retrospectivos e prospectivos de pinos e núcleos metálicos e pinos de fibra em relação à taxa de sobrevivência e tipo de falhas prevalentes. A revisão de literatura foi realizada utilizando a base de dados MEDLINE com os seguintes termos para pesquisa: “Pino de fibra e estudo clínico”, “Pino de fibra e avaliação clínica”, “Pinos e núcleos metálicos e estudo clínico”, “Pinos intra-radiculares e estudo clínicos retrospectivos”. O período avaliado foi de Dezembro de 1990 até o final de Dezembro de 2010. Vários fatores biológicos, mecânicos e estéticos estão envolvidos na taxa de sobrevivência do procedimento restaurador de dentes tratados endodonticamente. A seleção do pino deve satisfazer e otimizar esses fatores. Dados com base em estudos clínicos de longo prazo são essenciais para o clínico geral na tomada de decisões. Adequada indicação na seleção do sistema de pino devem ser feitas. Adicionalmente, desgaste mínimo da estrutura dentária existente deve ser priorizado. A presença de férula deve estar presente para garantir e melhorar a previsibilidade de pinos de fibra. Pinos de fibra de vidro têm demonstrado boa sobrevivência em estudos clínicos, com desempenho semelhante aos pinos metálicos e núcleos moldados e fundidos. Retentores metálicos apresentam boa sobrevivência clínica, no entanto as falhas envolvidas são em sua maioria irreversíveis, ao contrário do que acontece com os pinos de fibra de vidro.

Comparison of different ultrasonic vibration modes for post removal

This in vitro study compared different ultrasonic vibration modes for intraradicular cast post removal. The crowns of 24 maxillary canines were removed, the roots were embedded in acrylic resin blocks, and the canals were treated endodontically. The post holes were prepared and root canal impressions were taken with self-cured resin acrylic. After casting, the posts were cemented with zinc phosphate cement. The samples were randomly distributed into 3 groups (n=8): G1: no ultrasonic vibration (control); G2: tip of the ultrasonic device positioned perpendicularly to core surface and close to the incisal edge; and G3: tip of the ultrasonic device positioned perpendicularly to core surface at cervical region, close to the line of cementation. An Enac OE-5 ultrasound unit with an ST-09 tip was used. All samples were submitted to the tensile test using an universal testing machine at a crosshead speed of 1 mm/min. Data were subjected to one-way ANOVA and Tukey's post-hoc tests (α=0.05). Mean values of the load to dislodge the posts (MPa) were: G1 = 4.6 (± 1.4) A; G2 = 2.8 (± 0.9) B, and G3= 0.9 (± 0.3) C. Therefore, the ultrasonic vibration applied with the tip of device close to the core's cervical area showed higher ability to reduce the retention of cast post to root canal.

Este estudo in vitro comparou diferentes modos de vibração ultra-sônica na remoção de pinos intra-radiculares fundidos. As coroas de 24 caninos superiores foram removidas, as raízes foram incluídas em blocos de resina acrílica e tratadas endodonticamente. Os espaços para os pinos intra-radiculares foram preparados e depois moldados com resina acrílica autopolimerizável. Após a fundição, os pinos intra-radiculares foram cimentados com cimento de fosfato de zinco. As amostras foram distribuídas aleatoriamente em três grupos (n=8): G1: sem vibração ultra-sônica (controle), G2: ponta do aparelho ultra-sônico posicionada perpendicularmente à superfície do núcleo e perto da borda incisal e G3: ponta do aparelho ultra-sônico posicionada perpendicularmente à superfície do núcleo na região cervical, perto da linha de cimentação. Uma unidade de ultra-som Enac OE-5 com uma ponta ST-09 foi usada. Todas as amostras foram submetidas ao teste de tração utilizando máquina universal de ensaios a uma velocidade de 1 mm/min. Os dados foram submetidos aos testes ANOVA e Tukey post-hoc (α = 0,05). Os valores médios de carga para deslocar os pinos (MPa) foram: G1 = 4,6 (± 1,4) A; G2 = 2,8 (± 0,9), B e G3 = 0,9 (± 0,3) C. Portanto, a vibração ultra-sônica aplicada com a ponta do dispositivo perto da zona cervical do núcleo apresentou maior capacidade de reduzir a retenção de pinos metálicos fundidos no canal radicular.

A comparative evaluation of the fracture resistance of endodontically treated teeth with compromised intra radicular tooth structure using three different post system.

Intra-radicular loss of tooth structure in endodontically treated teeth poses a challenge. Available methods for treatment are cast post-core, intra-radicular resin reinforcement using composite resin followed by placement of prefabricated metal/fibre post (glass or carbon).This study is an attempt to investigate the validity of treatment of such teeth using above methods and evaluate which post system is best suited for rehabilitation. Thirtysix endodontically treated anterior teeth were prepared by uniformly removing intra-radicular tooth structure from buccal, lingual, mesial & distal surfaces such that only 0.75mm-1mm remained. Twelve teeth were subsequently restored with cast metal post & core, 12 with intra-radicular resin reinforcement followed by prefabricated titanium post (Luminex post system) & 12 with intra-radicular resin reinforcement followed by glass fibre post (Luscent Anchor post system). Statistical analysis used was t-test. There was no statistically significant difference between the 3 post systems, but it was observed that cast post & cores caused more apical & oblique fractures, rendering the teeth unrestorable. Teeth restored with intra-radicular resin reinforcement & placement of titanium or glass fibre post failed with root fractures limited to the coronal aspect along with dislodgement of post. Intra-radicular resin reinforcement offers advantages like preventing the metal display of the post through the thin dentinal wall, reinforcement of the thin walled teeth & comparable fracture resistance to cast post and core.

A comparative evaluation of fracture resistance of endodontically treated teeth restored with different post core systems: an in-vitro study

PURPOSE: To compare the fracture resistance and the mode of failure of endodontically treated teeth restored with different post-core systems. MATERIALS AND METHODS: Root canal treatment was performed on 40 maxillary incisors and the samples were divided into four groups of 10 each. For three experimental groups post space preparation was done and teeth were restored with cast post-core (Group B), stainless steel post with composite core (Group C) and glass fiber post with composite core using adhesive resin cement (Group D). Control group (A) samples were selected with intact coronal structure. All the samples were prepared for ideal abutment preparation. All the samples were subjected to a load of 0.5 mm/min at 130degrees until fracture occurred using the universal testing machine. The fracture resistance was measured and the data were analyzed statistically. The fracture above the embedded resin was considered to be favorable and the fracture below the level was considered as unfavorable. The statistical analysis of fracture resistance between different groups was carried out with t-test. For the mode of failure the statistical analysis was carried out by Kruskal-Wallis test and Chi-Square test. RESULTS: For experimental group Vs control group the fracture resistance values showed significant differences (P<.05). For the mode of failure the chi-square value is 16.1610, which means highly significant (P=.0009) statistically. CONCLUSION: Endodontically treated teeth without post core system showed the least fracture resistance demonstrating the need to reinforce the tooth. Stainless steel post with composite core showed the highest fracture resistance among all the experimental groups. Teeth restored with the Glass fiber post showed the most favorable fractures making them more amenable to the re-treatment.

Adaptación del sistema espiga muñón en relación a la preparación del conducto / Fit of the cast post and core system with different canal preparations

Se realizó un estudio in vitro que tuvo por objetivo medir el grado de adaptación del sistema espiga muñón, debido a que es uno de los factores fundamentales para lograr un buen anclaje de estos artificios, medido a nivel del núcleo de éste con respecto a los planos radiculares y de la espiga a las paredes del conducto, cuando es conformado con fresas Peeso y cuando es conformado usando fresas Peeso terminando con fresas del sistema Mooser. Seleccionamos 40 dientes que se dividieron al azar en dos grupos de 20, denominados P y M, respectivamente. Se confeccionó en cada muestra, previamente tratado su conducto mediante método indirecto, un perno muñón colado que fue probado en la preparación donde se midió el ajuste del muñón propiamente tal, después de logrado el asentamiento adecuado mediante desgastes en las interferencias de la espiga fueron cementados, posteriormente se realizaron dos cortes transversales a todo el espesor de la raíz a diferentes alturas, donde se midió la interfase entre la espiga y las paredes del conducto (adaptación). Los resultados fueron analizados utilizando los test de Mann-Whitney, Tukey y test T pareado, con software Systat versión 11, encontrándose que la mejor adaptación se observa en las muestras del grupo M en los dos sitios observados, comparadas con las del grupo P Estas diferencias son estadísticamente significativas.

We carried out a research aimed to determine the adaptation of the system called cast post and core, because it's one of the main factors to achieve a good adaptation of these devices measured from the core of this device to radicular plan, and from the post to the canal protesic's surface, when this one was prepared with Peeso's burs, and when was also prepared starting with Peeso's burs but finishing with Mooser system's burs. For that objective, we selected 40 teeth that were divided randomly into two groups of 20, called P and M respectively. A cast post and core was made in each sample through indirect method, previously treated the protesic canal. The cast post and core was tested in the preparation where the fit of the core was measured. Once achieved the proper settlement through the wearing out of the post's interferences and once the cast post and core was cemented, we made two cross cuttings to the thickness of the root at two differents levels, where the interface between the post and canal protesic's surface was measured (adaptation). The results were analyzed using the Mann-Whithny test, Tukey and paired T test, with Systast software version 11, having found that the best adaptation was observed in the samples of group M at the two points analyzed, compared to group P. These differences are statistically significant.

Resistencia a la fractura de premolares tratados endodónticamente, restaurados con dos sistemas de pernos y núcleo / Fracture resistance in endodontically treated premolars restored with two systems of posts

Objetivos: Medir la resistencia a la fractura en premolares tratados endodónticamente, restaurados con dos sistemas de pernos (Colados/ Prefabricados) y analizar el patrón de fractura que se produce en la raíces. Materiales y Métodos: a 60 premolares humanos monorradiculares se les realizó la terapia endodóntica. Se dividió la muestra aleatoriamente en dos grupos (30 c/u), el grupo 1 (G1FV) se restauró con pernos prefabricados de Fibra de Vidrio (Ángelus®) y el grupo 2 (G2C) con pernos colados de aleación base (Orca Plus /Ventura), utilizando cemento resinoso Nexus 2 (Kerr), los 2/3 coronales de ambos grupos fueron restaurados con resina compuesta híbrida (Glacier A1/ SDI). Las muestras fueron cargadas a una velocidad de 2mm/min y a una angulación de 30° con el eje longitudinal del diente en la máquina de prueba universal (Shimadzu AGS- J), la resistencia a la fractura fue medida en newtons y analizada con ANOVA de una vía; por medio de la observación directa y Rx se determinó el patrón de fractura que fue analizado con X² y Prueba Z. Resultados: En relación a resistencia a la fractura no hubo diferencia estadísticamente significativa entre los grupos (p=0,741). En cuanto al patrón de fractura se observó diferencia estadísticamente significativa entre los grupos estudiados (Zc=4,47). Conclusiones: En las condiciones en las que se realizó esta investigación se observó que los dos sistemas de perno y núcleo resisten de manera similar a las tensiones inducidas. En cuanto al patrón de fractura radicular en el G1FV se producen menor número de fracturas no reparables cuando se compararon con el G2C.

Objective: The purpose of this research was to compare the fracture resistance of human premolars restored with prefabricated fiber glass posts and custom cast post and to analyze the nature of the root fracture patterns. Methods: 60 human monoradicular premolars were prepared with endodontic therapy and randomly assigned to one of two groups: group 1 (G1FV) recovered with prefabricated fiber glass posts (Ángelus) or group 2 (G2C) with custom cast base alloy posts (Orca /Ventura Extra) using resinous luting cement (Nexus2/Kerr). 2/3 of the crowns were restored with hybrid composite (Glacier A1/SDI). The samples were loaded at a speed of 2mm/min and to a 30° angulation with the longitudinal axis of the tooth in the universal testing machine (Shimadzu AGS- J).The fracture resistance was recorded and analyzed with one way ANOVA. The nature of the root fracture patterns was determined through direct observation and Rx; these data were analyzed with X² and Z test.Results: After the ANOVA analysis no statistically significant differences were observed in relation to fracture resistance between groups (p = 0,741). However, significant differences were found for the nature of the root fracture between the groups (Zc=4, 47). Conclusions: Under the conditions of this study, both systems of posts have a similar fracture resistance. In relation to root fracture patterns, there are less catastrophic fractures in the G1FV when compared to G2C.

Distribución de los esfuerzos en tramos protésicos fijos de tres unidades con elementos intrarradiculares colados y prefabricados: análisis biomecánico utilizando un modelo de elementos finitos / Stress distribution in three unit fixed partial prosthesis with cast and prefabricated post and core: a biomechanical finite element analysis

Introducción: en esta investigación se analiza el comportamiento de la distribución de los esfuerzos en tramos de prótesis parcial fija (PPF) utilizando un modelo de elementos finitos. Métodos: se hicieron dos modelos de un incisivo central y un canino como pilares y de un incisivo lateral como póntico, los pilares fueron simulados con tratamiento endodóntico, con unrecorte de la gutapercha dejando 4 mm apicales y con elementos intrarradiculares prefabricados y colados para ambos pilaresen diferentes modelos, los cuales soportan una estructura en metal noble cubierta por cerámica. Para mayor fidelidad se hizo un modelo tridimensional de las estructuras de soporte periodontal (hueso cortical, esponjoso y ligamento periodontal), pormedio de un software que tiene la capacidad de mostrar el comportamiento de los cuerpos al introducirle algunas propiedades mecánicas de los elementos que componen el sistema. El modelo fue sometido a un esfuerzo de 1 N porque solo muestra el patrón de comportamiento de la distribución del esfuerzo sin llegar al límite de falla, con inclinación de 45º sobre los cíngulos del canino, central y póntico similar a la que se tienen en una oclusión normal. Resultados: se observó esfuerzo de von Mises en la dentina del canino: aleación de metal noble de 0.92 N/mm² y fibra de vidrio 1,17 N/mm². El esfuerzo de von Mises en la dentina del central:aleación de metal noble 1,11 N/mm² y fibra de vidrio 1,92 N/mm². Conclusiones: la distribución de los esfuerzos fue parecida a la obtenida en los dientes únicos, donde cuando se utilizan elementos intrarradiculares rígidos, este asume la mayor parte delesfuerzo por sus propiedades mecánicas. La decisión de cuál elemento intrarradicular elegir depende de muchas variables.

Introduction: this study analyzes the behavior of stress distribution in three-unit fixed partial dentures (FPD) usinga finite elements model (FEM). Methods: a canine and a central incisor were modeled; both of them were joined together by a FPD with a lateral incisor as pontic. Endodontic treatment with a 4 mm apical seal was simulated for abutment teeth; cast post and cores and prefabricated posts were modeled for abutments and a noble metal framework veneered with porcelain was used as thefinal restoration. For better precision, a three-dimensional model of supporting structures such as cortical bone, trabecular bone and periodontal ligament was designed. Software capable of showing the behavior of bodies when different mechanical properties are introduced to the system was used. Oblique loads of 1N in a 45° angle were applied on the cingulum area of both abutments and pontic which was intended to show the distribution of stress without failing. Results: the greatest strain was found on boththe canine and central incisor dentine where fiber posts were used (0.92 N/mm2 cast post and core, 1.17 N/mm2 fiber post on the canine; 1.11 N/mm2 cast post and core, 1.92 N/mm2 fiber post for the central incisor). Conclusions: distribution of von Missesstress was found to be similar to that of single tooth. When rigid intraradicular elements were used, this element absorbs most of the energy. The decision of which element is better depends on different variables.

Stress distribution of periodontally involved teeth restored with various posts: three-dimensional finite element study / 대한치과보철학회지

STATEMENT OF PROBLEM: The endodontically treated tooth is generally restored with post and core, owing to the brittle and the loss of large amount of tooth structure. As periodontal treatment was developed, there are many cases that periodontally involved teeth used in prosthetic treatment. PURPOSE: The purpose of this study was to analyze the stress distribution in the dentin and post structures by the various post materials and the amount of remaining alveolar bone height. MATERIAL AND METHOD: The 3-dimensional finite element models of mandible 1st premolars were divided into six types according to the various amount of remaining alveolar bone and post type. All types were modeled using equal length, diameter and shape of the post. Three types of post and core materials were used: prefabricated titaniumpost and amalgam core, prefabricated stainless steel post and amalgam core, and cast gold post and core. 300 Newton force was applied to functional cusp of mandible 1st premolar. RESULTS: The results were as follows: First, there was no apparent difference in the pattern of stress distribution according to the alveolar bone condition concentrate on the post middle area. Second, there was difference in pattern of stress distribution according to the core materials, gold post and core generated same than amalgam core. Third, there was no apparent difference in the pattern of stress distribution within the dentin according to the post and core materials. But a cast gold post and core generated the lowest maximum stress value, a stainless steel post generated the highest maximum stress value. Fourth, in the reduced alveolar bone model, maximum stress value is 1.5 times than that of the normal alveolar bone model. CONCLUSION: Within the limitations of this study, to provide minimal stress to the root with alveolar bone reduced, the post length may be as long as apical seal was not destroyed. To prevent fracture of tooth, it is rational to use gold alloy which material was good for stress distribution for post materials.

Comparison of fracture strength and pattern of endodontically treated teeth restored with fiber posts and metal cast post / 대한치과보철학회지

PURPOSE: The purpose of this study is to compare the effect of two fiber post systems and one metal cast post system on the fracture strength and fracture pattern of crowned, endodontically treated teeth with 2 mm-height of the reamining tooth structure. MATERIALS AND METHODS: A total of 36 recently extracted sound human mandibular premolars were selected. Each tooth structure of the crown portion except 2mm-height of the one above the cementoenamel junction was removed. After being endodontically treated, they were randomly distributed into 3 groups: group 1, restored with quarts fiber post(D.T. Light-Post), group 2, with glass fiber post(FRC Postec), and group 3, metal cast post and core. All teeth were fully covered with nonprecious metal crowns. Each specimen was embedded in an acrylic resin block and then secured in a universal load-testing machine. A compressive load was applied at a 130 degree angle to the long axis of the tooth until fractured, at a crosshead speed 20mm/min. The highest fracture loads were measured and recorded as the fracture strength of each specimen. Fracture areas were measured on the mid-buccal and mid-lingual point from the crown margins. One-way analysis of variance and Turkey test were used to determine the statistic significance of the different fracture loads and areas among the groups(p.05). The mean fracture area of the fiber post was closer to the crown margin than that of the metal cast post and core(p<.05). The metal cast post showed unrestorable and catastrophic fracture patterns. CONCLUSION: Within the limitations of this study, fracture loads with any statistically significant difference were not recorded for endodontically treated teeth restored with two fiber posts and the metal cast post. But teeth restored with the fiber posts typically showed the fracture pattern close to the crown margin, which was almost restorable.

A STUDY ON THE FRACTURE STRENGTH OF TEETH RESTORED WITH A CARBON FIBER POST UNDER CYCLIC LOADING / 대한치과보철학회지

In the restoration of endodontically treated teeth, carbon fiber post was recently introduced. The purpose of this in vitro study was to investigate the fracture strength of teeth restored with a preFabricated carbon fiber post in comparison with teeth restored with a prefabricated titanium post & custom cast gold post after cyclic loading in the different environment. A total of 30 recently extracted human central incisors of similar dimension with crowns removed were used. All teeth were placed into acrylic blocks and every steps for post and core fabrication were made according to manufacture s instruction. The post length and core dimensions were standardizd. All teeth were divided into 6 groups 1) carbon fiber post / atmosphere, 2) titanium post / atmosphere, 3) gold post / atmosphere, 4) carbon fiber post / wet, 5) titanium post / wet, 6) gold post / wet. Carbon fiber post and titanium post were cemented in place using resin cementt and cores were fabricated with Ti-Core. Custom cast gold post was made from Dur clay pattern resin and cemented using resin cement, too. All specimens were thermocycled 10,000 times. After 50,000 cyclic loading, failure strength was measured using Instron testing machine. KruskalWallis test followed by Mann-Whitney test was used to compare the mean fracture strength. Results were as follows 1. All specimens showed lower fracture strength in wet environment after cyclic loading than in atmosphere condition, but did not reveal a significant difference. 2. There was no significant difference between carbon fiber post specimen and titanium post spec imen in the same environment. 3. Gold cast post specimen showed significant different greater fracture strength than those of others in the same environment. 4. Carbon fiber post specimen showed no root fracture.