Topographic analysis of fiber posts after surface disinfection with different methods

Aims: This study aims to comprehensively examine the surface morphology of fiber posts after undergoing various disinfection methods, utilizing scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Materials and Methods: Twenty-one fiber posts were randomly allocated into seven experimental groups, each consisting of three samples. The disinfection methods employed were as follows: GC - no disinfection treatment; GAL - immersion in 70% alcohol, following the manufacturer's recommended protocol; GHP - soaking in 2.5% sodium hypochlorite for a duration of 10 minutes; GCL - soaking in 2% chlorhexidine gluconate for a period of five minutes; GAC - 30-second etching with 35% phosphoric acid; GPH - soaking in 10% hydrogen peroxide for a duration of 20 minutes; and GSL - autoclave sterilization. Following the disinfection procedures, SEM was employed to scrutinize the surface topography of the posts, while EDX was utilized to identify the chemical elements present on the sample surfaces. Subsequently, a descriptive analysis was conducted on the SEM images and EDX data. Results: SEM analysis revealed that all groups exhibited regions with epoxy resin-coated fibers alongside sections with exposed glass fibers. Analysis of the EDX data indicated that there were no significant differences in the predominant chemical elements across the groups. Carbon (C) and oxygen (O) registered the highest peaks, followed by silicon (Si), zirconium (Zr), sodium (Na), aluminum (Al), and calcium (Ca). Conclusions: The disinfection methods under investigation did not induce substantial alterations in the surface morphology of the fiber posts.

Biomechanical performance of three fiberglass post cementation techniques: Imaging, in vitro, and in silico analysis.

PURPOSE: The structural integrity of the resin cement layer, the bond strength, and the biomechanical behavior of different fiberglass post cementation techniques were evaluated. METHODS: Thirty-three bovine incisors were divided into three groups (n = 11): conventional fiberglass post (CFP), conventional fiberglass post in flared root canals (CFL), and relined fiberglass post (RFP). Six specimens from each group were submitted for high-resolution microcomputed tomography (µCT) to evaluate the integrity and presence/volume of voids at the resin cement layer. Finite element analysis (FEA) of two three-dimensional (3D) models of each group were conducted, one considered ideal (without interface defects) and another containing the conditions identified in the µCT analysis. Push-out bond strength tests were conducted for all specimens. RESULTS: The CFL group had the greatest mean values of void (Thirds cervical: 73.67; middle: 95.67; apical: 47.33) and gap concentration (Thirds cervical: 14.67; middle: 15.83; apical: 8.33) compared with CFP and RFP. A significant difference in bond strength was observed between the cervical (1.33 MPa) and middle thirds (1.85 MPa) compared with the apical third (4.85 MPa) of the CFL. A significant difference was observed in the bond strength in the CFL (1.33 MPa) and RFP (3.29 MPa) in the cervical third, which were statistically similar to the bond strength of the CFP. The tensile stress distributions were similar in most structures, localized in the cervical region on the lingual surface. CONCLUSIONS: Structural defects in the interface layer might influence the bond strength and biomechanical behavior under the different fiberglass post cementations.

Post Placement and Restoration of Endodontically Treated Canines: A Finite Element Analysis Study.

The purpose of this study was to show the improved outcomes of restoring endodontically treated teeth with fiberglass posts compared to restorations using metal posts. In our study, we used the Finite Element Method (FEM), which is based on the principle that a physical model that supports a given load distributes the stress throughout its volume. We sought to assess what stress results in a tooth when it is restored using a fiberglass post compared to restoration using a metal post. The finite element analysis showed that a system consisting of a tooth with a fiberglass post is more stable in terms of the maximum stress than a system consisting of a tooth with a metal post. The maximum displacements and deformations were obtained in the case of a canine restored with a fiberglass post, which showed that this system had a high elasticity, therefore, higher strength than a canine restored with a metal post, which had high rigidity.

PEEK and fiberglass intra-radicular posts: influence of resin cement and mechanical cycling on push-out bond strength.

OBJECTIVES: To evaluate the bond strength of four types of posts (pre-fabricated fiberglass post, fiberglass post anatomized with composite resin, milled fiberglass post, and milled polyetheretherketone (PEEK) post), and two types of resin cements (conventional and self-adhesive) by assessing immediate bond strength and post-mechanical aging at each root third. MATERIALS AND METHODS: Bovine endodontically treated roots (16 groups, n = 8) were prepared and the posts were produced and luted; the specimens of aging groups were cycled (300,000 cycles under 50 N load at 1.2 Hz frequency); six slices of each root were obtained; push-out test was performed by using a universal testing machine (500 N load at 1 mm/min cross speed); fracture pattern was classified into five levels. The statistical analyses used were three-way ANOVA, Tukey's test (for bond strength), and Fisher's test (for fracture pattern) (α < 0.05). RESULTS: Differences were found between the cements for posts (conventional: p < 0.001; self-adhesive: p = 0.002), whereas no difference was found for root region (p = 0.941; p = 0.056, respectively); analysis of each root showed significant differences for cements (p < 0.001), posts (p < 0.001), and mechanical cycling (p = 0.001); in terms of double interaction, differences were found for posts and mechanical cycling (p = 0.005); no other interactions were observed (double or triple); the fracture pattern showed difference between the groups for both cements. CONCLUSIONS: Milled PEEK posts seem to be a good clinical option, but they require improvement of CAD-CAM technology and advances towards their adhesion. CLINICAL RELEVANCE: Milled posts are promising and can reduce clinical time for rehabilitation of extensively destroyed teeth.

Evaluation of pretreatments on intra-radicular dentin bond strength of self-adhesive resin cements.

OBJECTIVES: To evaluate the influence of dentin pretreatments on the push-out bond strength (POBS) of self-adhesive resin cements (SARCs) to radicular dentin. MATERIALS AND METHODS: Two experimental pretreatments (2.5% titanium tetrafluoride (TiF4 ) and 26% polyacrylic acid (PA)) and two SARCs: Maxcem Elite (MAX) and Calibra Universal (CAL) were used. For each cement, a control group was applied as indicated by the manufacturer. Sixty bovine incisors were restored (n = 10) and subjected to POBS evaluation. Failure mode, adhesive interface and surface morphology were analyzed by a Scanning Electron Microscopy (SEM) and resin infiltration was performed by confocal laser scanning microscopy (CLSM). Data for POBS and CLSM were analyzed by three-way ANOVA and Bonferroni post-hoc (α = 0.05). RESULTS: For MAX, both experimental pretreatments resulted in increased POBS in the cervical third, and for CAL, only the PA resulted in higher POBS in the cervical third. The most failures occurred between the dentin and the resin cement, except when TiF4 was applied. For PA, analysis of surface morphology showed open dentinal tubules, while TiF4 presented particle agglomerates. SEM and CLSM images confirmed presence of resin tags for both pretreatments. CONCLUSION: Pretreating radicular dentin with PA and TiF4 solutions improves the bond strength of SARCs.

Long-Term Outcome of Nonvital Immature Permanent Teeth Treated With Apexification and Corono-Radicular Adhesive Restoration: A Case Series.

INTRODUCTION: This study aimed to evaluate the long-term outcome of 16 permanent maxillary central incisors with nonvital pulps and open apices treated with apexification and corono-radicular adhesive restorations, within a follow-up span of 5 to 22 years. METHODS: Fourteen patients providing a total of 16 teeth treated with mineral trioxide aggregate (n = 12), Biodentine (n = 3), or ß-tricalcium phosphate (n = 1) apical barrier and corono-radicular restoration, with or without fiberglass post, were included. Clinical and radiographic criteria were defined for assessment at recall. Restoration and periapical tissue status evaluation were performed according to FDI World Dental Federation's esthetic, functional, and biological criteria and Ørstavik Periapical Index (PAI). Outcome was dichotomized as "healed" (PAI ≤ 2, asymptomatic with absence of signs of infection) or "not healed" (PAI ≥ 3, presence of clinical signs and/or symptoms). RESULTS: Fourteen of 24 patients were available for the present study (recall rate = 58%). Within a follow-up of 5 to 22 years, 10 (62.5%) teeth were considered "healed," fulfilling both strict clinical and radiographic success criteria. Only 1 tooth was missing due to root resorption and 1 patient was presenting with clinical signs and symptoms at recall, resulting in a survival rate of 93.8%. CONCLUSIONS: Adhesive corono-radicular restoration in nonvital permanent immature teeth treated with apexification allows for favorable long-term outcomes, by ensuring structural reinforcement and coronal microleakage prevention. Teeth sustaining a substantial loss of coronal structure may require post/core placement. In the case of failure, this endodontic-restorative combination ensured teeth survival until growth phase conclusion, thus allowing for proper prosthetic rehabilitation approaches.

Resistencia a la fuerza de tracción de espigos de fibra de vidrio y anatomizados / Tensile bond strength of fiberglass and anatomized posts

Introducción: Es frecuente el desprendimiento de los espigos de fibra de vidrio por pérdida de adhesión cuando son sometidos a las fuerzas masticatorias. Objetivo: Comparar in vitro la resistencia a las fuerzas de tracción de espigos de fibra de vidrio y anatomizado con un mismo cemento. Métodos: Estudio in vitro, de tipo experimental. Se seleccionaron 20 premolares extraídos por motivos ortodónticos que fueron distribuidos aleatoriamente en dos grupos. Se les realizó el tratamiento de conductos por un especialista, la preparación fue manual y la técnica de obturación por condensación lateral. Los dientes fueron preparados para, en forma estándar, recibir el espigo de fibra de vidrio y anatomizados con resina. Para ambos grupos la cementación siguió el protocolo sugerido por el fabricante de Allcem Core® (cemento dual). Los especímenes fueron troquelados en acrílico de autocurado. Para luego ser sometido a fuerza de tracción vertical en la máquina de pruebas de materiales (Instrom©). Resultados: En el grupo de dientes con espigos anatomizados se obtuvo una media de 31 Kg/F, postes de fibra de vidrio 12,47 Kg/F. Según las pruebas de Shapiro-Wilk, las muestras presentaron distribución normal (p > 0,05). Se contrastó la hipótesis con la prueba de t de Student y se encontró diferencia estadística altamente significativas entre los grupos (p = 0,001) Conclusiones: Existe una mayor resistencia a la tracción vertical en los espigos anatomizados(AU)

Introduction: Fiberglass posts often fall off their position due to loss of adhesive capacity when they are subjected to masticatory force. Objective: Compare in vitro the tensile bond strength of fiberglass and anatomized posts cemented with the same adhesive material. Methods: An in vitro experimental study was conducted. A selection was made of 20 premolars extracted by orthodontic indication which were then randomly distributed into two groups. The premolars underwent root canal treatment by a specialist. The preparation was manual and sealing was performed by lateral condensation. The teeth were prepared in the standard manner to receive the fiberglass and resin-anatomized posts. In both groups' cementation followed the protocol suggested by the manufacturer of Allcem Core® (dual cement). The specimens were stamped in self-curing acrylic. Next, they were subjected to vertical tensile strength in an materials testing machine (Instrom©). Results: The mean values obtained were 31 kg/F for teeth with anatomized posts and 12.47 kg/F for fiberglass posts. According to Shapiro-Wilk tests, the samples exhibited a normal distribution (p > 0.05). The hypothesis was contrasted with Student's t test, obtaining a highly significant statistical difference between the groups (p = 0.001). Conclusions: Vertical tensile bond strength is greater in anatomized posts(AU)

Guided Endodontics in Root Canals with Complex Access: Two Case Reports

Abstract This article reported two clinical cases in which the guided endodontics was used to perform the access to the root canals. The first case presents a 40-year-old female with a history of pain related to the left maxillary canine. After radiographic examination, the presence of severe calcification up to the apical third of the root canal, associated with a periapical radiolucency, was noted. In the second case, an 85-year-old male was referred to our service with pain upon palpation, at the right mandibular first molar. The radiographic images revealed the presence of endodontic treatment and a fiberglass post in the distal root canal, which was associated with extrusion of the filling material and a periapical lesion. The 3D-guides were planned based on cone beam computed tomography and intraoral digital scanning, which were aligned using a specific software. Therefore, implant drills could be guided up to the root canal length required for each case. In the first case, a surgical root canal was created and the patient was free of signs and symptoms after the treatment was completed. In the second case, it was observed that the fiber post was worn by the drill, allowing free access to the filling material. It was possible to perform the endodontic reintervention in a more predictable way and in less time. In both cases, the use of the guided endodontics allowed the preservation of a large part of the dental structure. The procedures were performed faster, without the occurrence of fractures and perforations.

Resumo Este artigo relatou dois casos clínicos em que a endodontia guiada foi utilizada para realizar o acesso aos canais radiculares. O primeiro caso apresenta uma mulher de 40 anos com história de dor relacionada ao canino superior esquerdo. Após exame radiográfico, notou-se a presença de calcificação acentuada até o terço apical do canal radicular, associada a radioluscência periapical. No segundo caso, um homem de 85 anos foi encaminhado ao nosso serviço com dor à palpação no primeiro molar inferior direito. As imagens radiográficas revelaram a presença de tratamento endodôntico e pino de fibra de vidro no canal radicular distal, que estava associado à extrusão do material obturador e lesão periapical. Os guias-3D foram planejados com base em tomografia computadorizada de feixe cônico e escaneamento intraoral digital, os quais foram alinhados por meio de um software específico. Desta forma, brocas de implante puderam ser guiadas até o comprimento necessário do canal radicular para cada caso. No primeiro caso, foi confeccionado um canal radicular cirúrgico e o paciente ficou sem sinais e sintomas após o término do tratamento. No segundo caso, observou-se que o pino de fibra foi desgastado pela broca, permitindo o livre acesso ao material obturador. Foi possível realizar a reintervenção endodôntica de forma mais previsível e em menos tempo. Em ambos os casos, o uso da endodôntica guiada permitiu a preservação de grande parte da estrutura dentária. Os procedimentos foram realizados com maior agilidade, sem a ocorrência de fraturas e perfurações.

Adhesive strength of fiberglass posts treated with thio-urethane-based experimental silanes.

PURPOSE: The aim of this study was to evaluate the adhesive bond strength of fiberglass posts treated with experimental silanes based on thio-urethane and submitted to thermo and mechanical cycles. MATERIALS AND METHODS: Bovine roots were divided into six groups: RX-RU2 (RelyX CP + RelyX U200); PETMP-HDDI-RU2 (PETMP-HDDI + RelyX U200); PETMP-BDI-RU2 (PETMP-BDI + RelyX U200); RX-RU (RelyX CP + RelyX Ultimate); PETMP-HDDI-RU (PETMP-HDDI + RelyX Ultimate); PETMP-BDI-RU (PETMP-BDI + RelyX Ultimate). One slice from each root third (n=10) was submitted to the push-out test and the values evaluated with R Program statistical analysis, while the failure pattern assessed in percentage. RESULTS: Among root thirds, RX-RU2 promoted greater strength at the cervical and apical thirds; PETMP-HDDI-RU2 showed highest values at the three thirds; and PETMP-BDI-RU2 was strongest at the apical third. RX-RU presented higher strength at the apical third, and PETMP-HDDI-RU and PETMP-BDI-RU had similar values at the three thirds. In each root third, PETMP-HDDI-RU2 showed similar strength at all thirds, and similar strength at the apical third was observed for other associations. Mixed and adhesive failures predominated. CONCLUSION: Experimental silanes promoted different bond strength values in the adhesion of fiberglass posts to the root thirds, with better results for PETMP-HDDI silane. The root region did not influence the failure pattern and most slices showed mixed (MCDP) or adhesive (ADP) failure.

Temporary cement residues affect the bond strength and dentin penetration of self-adhesive resin cement in fiberglass post cementation.

This study evaluated the persistence of eugenol-containing (PR, Provy) or eugenol-free (RT, Relyx Temp, and TB, Temp Bond) temporary cement residues and its effects on push-out bond strength and dentinal penetration of the self-adhesive resin cement (Relyx U200). Eighty human roots were endodontically treated and post space prepared. Fourty specimens were distributed in four groups (n = 10): Control (CO), without any clinical procedure, PR, RT, and TB, where a metallic post was cemented with one of the temporary cements. After metallic post removal, hemi sections post space were submitted to SEM analysis. Another specimens were distributed in similar groups, but fiberglass post was cemented using Relyx U200 cement and submitted to push-out bond strength and dentinal penetration cement analysis, in post space thirds. SEM analysis were evaluated by Kruskal-Wallis and Dunn tests, while bond strength and dentinal penetration were evaluated by ANOVA One-Way and Tukey test (p < .05). Only in apical thirds, PR, RT, and TB showed higher persistence of residues than CO. In bond strength, PR, RT, and TB showed lower values than CO, in all post space thirds (p < .05). But to dentinal penetration, PR, RT, and TB presented lower values than CO only in apical thirds (p < .05). There is the greatest persistence of temporary cement residues only in apical post space third, providing less dentinal penetration of the self-adhesive resinous cement. However, the previous use of temporary cements has negative effects on the bond strength cementation system, regardless of the third evaluated.

Push-out bond strength of fiberglass posts cemented with adhesive and self-adhesive resin cements according to the root canal surface.

Evaluating the bond strength of fiberglass posts cemented with different resin cements. MATERIALS AND METHODS: Seventy freshly extracted roots of healthy human canines were endodontically treated and prepared to receive fiberglass posts. The roots were randomly divided into seven groups: (G1) RelyX ARC, (G2) Enforce, (G3) BisCem, (G4) Duo-Link, (G5) Cement Post, (G6) Variolink II, and (G7) RelyX U200. After post cementation, the specimens were sectioned perpendicularly to the root axis using a high-speed diamond disc, totaling 340 specimens. The strength values obtained in the push-out test were submitted to two-factor ANOVA and Tukey test (p = 0.05). RESULTS: The root thirds (p = 0.001) and the type of cement (p = 0.001) influenced the bond strength values. The relation between these two factors was also significant (p = 0.011). CONCLUSIONS: The bond strength of self-adhesive resin cements was significantly higher as compared to other cements. Besides the cervical third in roots cemented with conventional cements types presented the highest bond strength values (p < 0.05).

Comparison of the Resistance of Bond Strength of Cemented Fiberglass Posts in Different Root Thirds with and without Silanization: An Ex Vivo Study.

AIM: To compare the application of silane in the bond strength of fiberglass posts in different thirds of the cemented root with a self-adhesive system in an ex vivo study. MATERIALS AND METHODS: Freshly extracted teeth were collected, which had indication of extraction for periodontal or orthodontic reasons. The study evaluated n = 42 specimens that were divided into two large groups: I (control, without silane) and II (with silane); the resistance to adhesion in the respective thirds of the root (cervical, middle, and apical) was also evaluated. The prefabricated fiberglass posts were cemented with and without silane according to the manufacturer's instructions and were cemented with a resin-based cementing agent. The adhesion strength test was evaluated by the universal testing machine. RESULTS: According to the results of this experimental trial, the fiberglass posts that did not receive silane had the highest adhesion strength of 26.5 ± 10.6 MPa, while silane-cemented posts only had 21.7 ± 8.1 MPa. The statistical analysis was performed using the Kruskal-Wallis test and work with a level of significance of p < 0.05. CONCLUSION: The use of silane as part of the cementing protocol in fiberglass posts does not influence the adhesion strength between the surfaces of the posts and the resin cement because there were statistically significant differences between both adhesion protocols. CLINICAL SIGNIFICANCE: This study has a great impact because according to the results, clinical decisions can be made when cementing the fiberglass posts through the application of silane or not.

A Fiberglass and Resin Post Technique Combined with Fragment Collage of an Upper Central Incisor: Multidisciplinary Treatment / Unión de fragmento de un incisivo central superior con una técnica combinada: Tratamiento multidisciplinario

ABSTRACT: The clinical treatment of anterior tooth fractures requires specialized knowledge, technical skill, and a degree of artistic sense to ensure successful treatment. Herein, we describe the reattachment of an original tooth fragment with endodontic involvement via the utilization of a micro-hybrid composite resin and an aesthetic fiberglass post.

RESUMEN El tratamiento clínico de las fracturas coronarias en dientes anteriores superiores requiere de conocimientos especializados, habilidades técnicas y un grado de sentido artístico para garantizar un exitoso tratamiento. En este reporte de caso, se describe la unión de un fragmento de un incisivo superior, que requirió previamente un tratamiento endodóntico, mediante la utilización de una resina compuesta micro- híbrida y un poste de fibra de vidrio.

Comparison of the Microtensile Bond Strength of a Polyetherketoneketone (PEKK) Tooth Post Cemented with Various Surface Treatments and Various Resin Cements.

The aim of this in-vitro research was to evaluate the microtensile bond strength in the newly introduced PEKK tooth post with various surface treatments and resin cements. A fiberglass tooth post was included in order to compare it with PEKK as a possible post material. The microtensile bond strengths of the fiberglass post (FRC Postec Plus) and the PEKK post (Pekkton®) were tested using three kinds of self-adhesive resin cements (G-CEM LinkAce, Multilink Speed, and RelyX U200) and one self-etching resin cement (PANAVIA F2.0). The surface treatments of the fiberglass posts were processed according to the manufacturer's recommendations (F1, application of 37% phosphoric acid etching gel and silanization). For the PEKK post groups, various surface treatments were performed like no surface treatment (P1), sandblasting (P2), silica-coating and silanization (P3), and sandblasting with a composite primer (P4). In the surface treatment, PEKK posts with silica coating and silane treatment (P3) showed a significantly higher microtensile bond strength (mean MPa: 18.09, p < 0.05). The highest microtensile bond strength was shown when the PEKK posts were treated with a silica coating and silane treatment and cemented with RelyX U200 (mean MPa: 22.22). The PEKK posts with surface treatments of silica-coating and silanization or sandblasting displayed superior microtensile bond strengths (mean MPa: 18.09 and 16.25, respectively) compared to the conventional fiberglass posts (mean MPa: 14.93, p < 0.05).

Biomechanical Effect of Ferrule on Incisors Restored with a Fiberglass Post and Lithium-Disilicate Ceramic Crown after Thermal Cycling and Fatigue Loading.

PURPOSE: To evaluate the biomechanics of endodontically treated incisors restored with a fiberglass post and a CAD/CAM lithium-disilicate ceramic crown with/without a ferrule after thermal and mechanical aging. MATERIALS AND METHODS: Twenty bovine incisors were divided into two groups (n = 10): 1. Fe, with a ferrule of 2 mm, and 2. NFe, without a ferrule. After endodontic treatment, the teeth were restored using a fiberglass post (Exacto 3, Angelus) and composite core (Tetric Ceram, Ivoclar Vivadent). They then received a CAD/CAM lithium-disilicate ceramic crown (IPS e.max CAD) luted using a self-adhesive composite (RelyX Unicem 2, 3M Oral Care). All specimens were subjected to 20,000 thermocycles and 2,400,000 simulated chewing cycles. Ceramic crown and root dentin strains (µS) were measured using strain gauges (n = 10) during 100-N loading before and after the thermal and mechanical aging, and upon fracture loading. The specimens were subsequently loaded to fracture (N). The stress distribution was analyzed using 3D individualized finite-element models created by micro-CT of experimental samples (n = 3). Strain data were analyzed using two-way ANOVA and Tukey's HSD test. Fracture resistance was analyzed using Student's t-test and fracture mode was analyzed using the chi-squared test (α = 0.05). RESULTS: After aging, NFe exhibited significantly higher root dentin deformation (buccal: 1248.0 ± 282.8; lingual: 516.2 ± 195.0; p < 0.001) than Fe (buccal, 554.0 ± 233.8; lingual: 311.8 ± 159.0; p < 0.001). The deformation measured on ceramic crowns was not influenced by ferrule presence or aging process. Significantly higher fracture resistance (N) was observed for the Fe (1099.6 ± 214.8) than the NFe group (675.3 ± 113.8) (p < 0.001). The NFe group revealed a lower fracture resistance:root strain ratio than did the Fe group. The stress levels on root dentin and fiberglass were lower for the Fe group. CONCLUSION: The NFe group showed increased root dentin strain after the aging process. The Fe group revealed higher fracture resistance, lower stress concentration on root dentin and fewer catastrophic fractures.

Influence of light transmission through fiber posts: Quantitative analysis, microhardness, and on bond strength of a resin cement.

CONTEXT: Light transmission (LT) into deeper areas of the dentin root is limited. AIM: The aim of this study is to perform a quantitative investigation of the radial transmission of light (LT) through different fiber posts and its influence on the Knoop hardness number (KHN) and bond strength (BS) of a dual-cure self-adhesive resin cement at 3 different depths. MATERIALS AND METHODS: Four types of fiber posts (2 translucent and 2 conventional) were used. LT and KHN analyses were performed in a specially designed matrix, which allowed measurements at 3 different depths. LT was measured using a volt-ampere meter while KHN tests were performed in a microhardness tester. For BS analysis, endodontically treated bovine roots were divided into 4 groups, each group receiving one type of post. After cementation, cross sections of the root were tested for resistance to displacement using a universal testing machine. STATISTICAL ANALYSIS USED:: Statistical analysis was performed by using this ANOVA and Tukey's test. RESULTS: For LT, translucent posts showed significantly higher values at all depths compared to the conventional ones. For all posts, LT decreased at the deeper depths. The KHN results showed no statistical differences among the different posts, regardless of depth. For BS, a translucent post showed the highest values, and comparative analyses between the different depths of posts also showed statistically significant differences while comparisons among the different depths of the same post showed no differences. CONCLUSIONS: LT depended on the type of post and on depth. The type of post did not significantly influence the cement KHN. A translucent post showed higher BS in pooled data.

Fracture resistance of endodontically treated molars restored with horizontal fiberglass posts or indirect techniques.

BACKGROUND: Because of the many possibilities for endodontically restoring the posterior teeth and the high prevalence of restoration failures, this topic continues to be of major concern. A composite resin (CR) restoration reinforced by a horizontal fiberglass post may improve the fracture resistance of endodontically treated teeth. The authors investigated this possibility by comparing the fracture resistance of molars restored with direct techniques with that of molars restored with indirect techniques. METHODS: The authors divided 50 extracted sound third molars into 5 groups: sound teeth, onlay (ON), inlay (IN), direct CR, and transfixed fiberglass post (TFP) plus direct CR. The authors performed standardized mesio-occlusodistal cavity preparations and endodontic treatments. The authors cemented indirect restorations of Lava Ultimate (3M ESPE) adhesively in the ON and IN groups. The authors restored CR group teeth directly with Filtek Z230 XT (3M ESPE). In the TFP group, the authors transfixed 2 fiberglass posts horizontally and restored the teeth directly with CR. Thereafter, the authors submitted the teeth to cyclic fatigue loading with 500,000 cycles at 200 newtons. The authors tested fracture resistance in newtons in a universal testing machine. The authors analyzed data with 1-way analysis of variance and a Tukey test (P < .05). RESULTS: Sound teeth had the highest fracture resistance. ON had the highest recovery of resistance, followed by TFP. CR had the lowest recovery, which was similar to that of IN. CONCLUSIONS: Endodontically treated molars restored with TFP plus CR had fracture resistance similar to those restored with ON, which was higher than that for IN or CR only. PRACTICAL IMPLICATIONS: Horizontal TFPs placed inside a composite restoration had the same performance as did ON restorations.

Effect of Instrumentation Techniques, Irrigant Solutions and Artificial accelerated Aging on Fiberglass Post Bond Strength to Intraradicular Dentin.

OBJECTIVE: To evaluate the effect of instrumentation techniques, irrigant solutions and specimen aging on fiberglass posts bond strength to intraradicular dentine. MATERIALS AND METHODS: A total of 120 bovine teeth were prepared and randomized into control and experimental groups resulting from three study factors (instrumentation techniques, irrigant solutions, specimen aging). Posts were cemented with RelyX U100. Samples were submitted to push-out test and failure mode was evaluated under a confocal microscope. RESULTS: In specimens submitted to water artificial aging, nickel-titanium rotary instruments group presented higher bond strength values in apical third irrigated with NaOCl or chlorhexi-dine. Irrigation with NaOCl resulted in higher bond strength than ozonated water. Artificial aging resulted in significant bond strength increase. Adhesive cement-dentin failure was prevalent in all the groups. CONCLUSION: Root canal preparation with NiTi instruments associated with NaOCl irrigation and ethylenediaminetetra acetic acid (EDTA) increased bond strength of fiberglass posts cemented with self-adhesive resin cement to intraradicular dentine. Water artificial aging significantly increased post-Clinical significance: The understanding of factors that may influence the optimal bond between post-cement and cement-dentin are essential to the success of endodontically treated tooth restoration.

Condicionamento de superfícies na Odontologia com plasma de argônio: uma revisão de literatura / Conditioning surfaces in Dentistry with argon plasma: a literature review

O objetivo deste estudo foi de verificar, por meio de revisão de literatura, os resultados do tratamento de diferentes superfícies de interesse para a Odontologia com gás argônio, um plasma frio à pressão atmosférica. Este vem sendo recentemente estudado e aplicado com o intuito de aumentar a molhabilidade do substrato condicionado, como zircônia, um material conhecidamente ácido resistente; dentina e pinos de fibra de vidro, interferindo positivamente na adesão. Diferentes estudos foram revisados, podendo-se concluir que o condicionamento com plasma frio de argônio alterou a superfície dos substratos testados, aumentando a área de superfície e, com isso, reduzindo o ângulo de contato. Isto contribui para uma maior molhabilidade do substrato e aumento da adesão às superfícies testadas.

The aim of this study was to verify, by means of literature review, the results of treatment of different areas of interest to Dentistry with Argon gas, a cold atmospheric pressure plasma. This subject has recently been studied and applied in order to increase the wettability of the substrate conditioning as zirconia, a well known acid-resistant material; Pins and dentin fiberglass positively interfering in adhesion. Different studies were reviewed, and shall be concluded that conditioning with cold argon plasma altered the surface of substrates, increasing the surface area and thereby reducing the contact angle. This contributes to a greatter wettability of the substrate and increased adherence to surfaces tested.

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.