Glass Fiber Posts Research Articles

Fatigue Properties of Weakened and Non-weakened Roots Restored with CAD-CAM Milled Fiber Post, Prefabricated Fiber Post, or Cast Metal Post.

Customized glass fiber posts using CAD-CAM technology have been suggested for restoring endodontically treated teeth. However, how weakened or non-weakened roots restored with anatomical CAD-CAM posts behave under cyclic fatigue is not clear. To evaluate the load-bearing capacity under fatigue (fatigue failure load [FFL], the number of cycles for failure [CFF], and survival probabilities) and fracture pattern of weakened and non-weakened roots restored with CAD-CAM fiber post and cores, metal cast-post-core, and prefabricated fiber post and resin core. A total of 60 crack-free bovine incisor roots (13 mm in length) with standard geometry were obtained and randomly allocated considering the factor "root condition" in two levels (weakened and non-weakened). Thus, half of the roots were weakened to obtain a wall thickness of 0.5 mm. After that, the endodontic treatment was executed, all roots embedded with acrylic resin and the specimens randomly allocated (n=10) considering the factor "post system" in three levels (CAD-CAM: CAD-CAM milled glass-fiber post and core; MBC: metallic-based post and core; and FRC: prefabricated glass-fiber post and composite resin core). The posts were luted with a dual-cure self-adhesive luting agent. Then, all teeth received a metallic crown. An initial load of 100 N at 20 Hz for 5000 cycles was applied for the step-stress fatigue test, followed by incremental steps of 50 N for 20,000 cycles each step, up to failure. A fracture pattern analysis was performed. CAD-CAM fiber post (FFL: 865 N; CFF: 311,000 cycles) presented similar fatigue performance (p>0.05) to FRC (FFL: 925 N; CFF: 335,000 cycles), with 100% of repairable fractures for non-weakened roots; however, both groups presented worse performance than MBC (p<0.05; FFL: 1265 N; CFF: 471,000 cycles) which led to 100% of catastrophic failures. No statistical difference was found in fatigue performance among the three systems for weakened roots (p>0.05; FFL: 1035-1170 N; CFF: 379,000-433,000 cycles), with a high rate of catastrophic failures. CAD-CAM fiber post presented similar fatigue performance to MBC and FRC approaches when restoring weakened roots. CADCAM was similar to FRC when restoring non-weakened roots, while MBC enhanced fatigue properties in this scenario.

Maximum compressive stress analysis in upper central incisors rehabilitated with fiberglass posts and three types of crowns. A study with the finite element method

To evaluate the maximum compressive stress in maxillary central incisors restored with fiberglass posts and three types of crowns by the FEM finite element method. The study was a virtual, descriptive, and laboratory trial. Three virtual models were made using the SolidWorks 2017 software from upper central incisors rehabilitated with fiberglass posts and a metal-ceramic crown, a monolithic lithium disilicate crown, and a zirconium-ceramic crown. They were then subjected to an oblique occlusal load of 150N with an angulation of 45°, distributed towards the palatal aspect. The stress analysis proceeded by comparing the maximum, minimum, and equivalent von Mises stresses. The maximum compressive stress was found at the cervical level in the vestibular area of each of the crowns. Zirconium-ceramic crown (Design 3) was the one with the highest compressive stress with 73.89 MPa, followed by Lithium Disilicate crown (Design 2) with 63.42 MPa and the metal-ceramic crown (Design 1) with 48.4 MPa. The zirconium-ceramic crown better distributes the stress along the tooth since, due to its rigidity, it absorbs the stresses that are concentrated especially in the cervical area, which could indicate that it is the most appropriate option to rehabilitate endodontically treated teeth.

Comparative Evaluation of Different Post Materials on Stress Distribution in Endodontically Treated Teeth Using the Finite Element Analysis Method: A Systematic Review.

The aim of this systematic review is to summarize and conclude findings to reveal the stress ranges developed by various post materials byfinite element analysis. This, in turn, aids in the selection of better post material clinically. The electronic databases PubMed and Google Scholar were searched in this review by using specific inclusion and exclusion criteria. Among 14586 articles, 22 articles were included in this systematic review, as they satisfied the eligibility criteria. The search covered all articles published from 1997 to December 2021. All records identified were retrieved and imported into the Rayyan bibliographic software, which is a systematic review screening software. Later, data extraction and analysis of 22 articles were done. Twenty-two articles, which were all finite element analysis studies, were included. Among these,18 studies used maxillary central incisor scanned models,two studies used a maxillary canine model, and the remaining two used the mandibular premolar model for finite element analysis. All these tooth models are restored with postmodels made of different materials. This systematic review revealeda difference in stress distribution in endodontically treated teeth when using different post materials. Among 22 studies, 15 studies evaluated glass fiber posts and the results showed that they induce less stress on restored endodontically treated teethwhen compared to other posts, with maximum stress concentration at the cervical third of the root. Prefabricated posts like stainless steel and Titanium showed more stress on the restored tooth structure with stress concentration at the cervical and apical third of the root. Prefabricated zirconia also showed more stress on the restored tooth with maximum stress concentration at the middle third of the root.

The impact of provisional intraradicular retainers cementation with temporary methacrylate-based resin in the bond strength of glass fiber posts to root dentin

Chemical composition of temporary cements interferes in the bond strength and quality of the bond interface of glass fiber posts to root dentin. The aim of the present study was to evaluate the influence of different temporary cements on the bond strength of fiberglass posts and resin cement. Thirty-two maxillary central incisor roots were standardized at 15 mm length. The root canals were prepared with Reciproc R50 and filled with a R50 single cone and AH Plus. Ten mm of filling material was removed with a heated Schilder condenser, leaving 5 mm of apical filling material. The roots were randomly distributed into 4 groups (n = 8). In the control group, the root canal was prepared with a standard drill according to the post diameter (DC #1, FGM, Joinville, Brazil), irrigated with 5 mL of distilled water and immediately received the fiberglass post cemented with self-adhesive resin cement. For the other groups, cores were made with temporary intraradicular retainers cemented with different temporary cements: methacrylate-based resin (Bifix Temp - Voco), calcium hydroxide-based (Provicol - Voco) and zinc oxide-based – eugenol-free (Relyx Temp NE - 3M). After 7 days, mechanical removal of the temporary retainers, preparation, irrigation of the root canal and cementation of the fiberglass post were performed, following the same protocol that had been performed in the control group. The roots were sectioned to obtain 3 slices per root third. The most cervical section of each third was used for the push-out test and failure pattern analysis, while the most apical section was subjected to analysis of the adhesive interface by scanning electron microscopy (SEM). The BS data were compared between groups using the two-way ANOVA and Tukey post-test. The failure pattern results were expressed in percentage and compared between groups using the chi-square test and the material adaptation data at the bond interface were evaluated using the Kruskal-Wallis and Dwass-Steel-Critchlow-Fligner tests. The results showed higher BS in the cervical third, with a higher value in the control group (10.8 ± 0.94) and Bifix Temp group (9.78 ± 0.71), with no statistically significant difference between these groups (P > .05). The middle and apical thirds showed no statistically significant difference (P > .05). As regards the type of failure, a higher percentage of mixed adhesive failures was observed for all groups. Analysis of the adhesive interface by SEM showed that the temporary cement Bifix Temp showed greater adaptation at the bond interface. It was concluded that the methacrylate-based resin temporary cement showed the highest bond strength values and best adaptation to root dentin than the zinc oxide-based and calcium hydroxide-based temporary cements.

An In Vitro Study Comparing the Diametral Tensile Strength of Composite Core Build-Up Material With Three Different Prefabricated Post Systems.

Statement of problemDental restorations are subjected to tensile stresses from oblique or transverse loading of their complex geometric forms, making tensile strength a fundamental mechanical property. Since composite core build-up materials are brittle, the integrity of the post and core depends on their tensile strength and resistance to fracture when utilized with various prefabricated post systems. Therefore, it is essential to determine the tensile strength of the prefabricated metallic and nonmetallic posts used to reinforce the composite resin core.PurposeThis study compared the diametral tensile strength (DTS) of three prefabricated post systems with composite core build-up material.Material and methodologyTen composite resin cores from four different groups were formed. The control group was the composite resin core without a post (group 1). Group 2 was composed of composites with metal posts, group 3 was composed of composites with glass fiber posts, and group 4 was composed of composites with carbon fiber posts. All the samples were kept in a humid place for seven days to mimic the conditions in the mouth. DTS was determined by recording the tensile force required to fracture the core material by performing a diametral compression test for tension after a week. The observations were analyzed using a one-way analysis of variance (ANOVA), followed by a post-hoc test.ResultsThe tensile strength of the resin core material was decreased by 28.1%, 20.8%, and 10.4% by using posts made of stainless steel, carbon fiber, and glass fiber, respectively. Among the three post systems, stainless steel had the lowest mean DTS values, while glass fiber had the highest mean DTS values.ConclusionComposite core glass fiber post systems showed higher tensile strength than other post systems.

Bond Strength Evaluation between Different Glass Fiber Post Systems to Restore Weakened Roots

A new bundled glass fiber-reinforced resin post was developed to be used in post-endodontic restoration. We evaluated the bond strength of a single prefabricated glass fiber post (GFP) and a bundled glass fiber-reinforced resin post (GT), used alone or combined, to restore weakened roots. Fifty bovine incisors roots were weakened with a diamond bur, except for those from the control group. The root canals were endodontically treated (Pro Taper Next system, gutta-percha, and endodontic cement), and the roots were divided into five groups (n = 10): Reb—single prefabricated GFP (Rebilda Post—Voco); GT—bundled glass fiber-reinforced resin post (Rebilda Post GT—Voco); RebGT—association between the prefabricated GFP (Reb) and the bundled one (GT); CP—prefabricated GFP customized with composite resin; and Cont—singular post in a non-weakened root (Control). All posts were cemented using a universal adhesive system (Futurabond U) and dual-cure resin cement (Rebilda DC—Voco). Afterwards, two slices were obtained from each root third (cervical, middle, and apical) and submitted to a push-out bond strength test. Data were analyzed regarding the post system used and the root thirds by two-way ANOVA, followed by Tukey’s test (p &lt; 0.05). There were higher bond strength means for the RebGT and CP groups, presenting values similar to the control. The Reb and GT groups showed lower values. The adhesion to deeper thirds of the root canal remains a challenge for adhesive dentistry and is not related to the design of the post. Additionally, the rehabilitation of teeth with weakened roots requires the customization of the glass fiber post with composite resin or the association between prefabricated options with multiple posts.

Compressive strength of premolars restored with ceramic crowns and supported with a glass fiber post using different luting agents

ObjectiveThe retention of glass fiber post (GFP) is considered a key factor for the long-term success of restorations of endodontically treated teeth. This study aimed to compare the compressive strength of a ceramic crown supported by a GFP using different luting agents. MethodsForty single-rooted premolars were randomly divided into four groups (n = 10 each): control group (teeth without a GFP), Ketac Cem group (glass ionomer), RelyX ARC group (conventional dual-curing resin), and RelyX U200 group (self-adhesive dual-curing resin). After luting of the posts and placement of all-ceramic crowns made using feldspathic porcelain (Noritake EX-3), they were exposed to thermocycling for 1000 cycles and compressive strength tests. Statistical analysis included Kruskal–Wallis test with Dunn’s multi-comparison test. ResultsThe Ketac Cem group and RelyX U200 group showed significantly greater fracture resistance to compressive loading than the control group. ConclusionThis study indicates a possible role of the luting agent used with the GFP in influencing the compressive strength of the restored teeth. In this study, the self-adhesive dual-curing resin and glass ionomer both offered resistance to fractures.

Comparative Evaluation of Push-Out Bond Strength &amp; Adaptation of A Fiber Post Cemented with Biodentine, MTA &amp; Resin Cement: An in Vitro Study.

Aim of our study is to evaluate &amp; compare the push-out bond strength and adaptation of a fiber post cemented with Biodentine, MTA, and dual-cure Resin cement. A total of thirty mandibular premolars with a single oval root canal were prepared and obturation was done by AH plus sealer and gutta-percha. The teeth were stored at 37 0C with 100% humidity for one day. The gutta-percha was removed by peeso reamer, leaving at least 4 mm of filling material, and post spaces were prepared by corresponding fiber post drill. The specimens were randomly distributed into (n=10) among each 3 groups. Glass fiber Posts were lutted with three different materials and coronally sealed with glass ionomer cement followed by stored in water for 24 h at 37 0 C. Each tooth was sectioned into 3 parts of 2-mm-thick slices in coronal, middle and apical zone. Push-out bond strength was measured with help of a universal testing machine and evaluated the adaptation by scanning electron microscope after 7 and 28 days. Statistical analysis was done by one-way anova and post hoc test. The push-out bond strength of dual-cure resin and Biodentine was non-significant but higher in comparison to Pro Root MTA. Dual cure resin cement and Biodentine also showed better surface adaptation to post in comparison to MTA. This present study showed that Biodentine can also be used for luting the fiber post as an alternative to dual-cure resin cement.

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.

Glass fiber post resistance to dislodgement from radicular dentin after using contemporary and conventional methods of disinfection

AimThe present study aimed to assess the bond integrity of curcumin photosensitizer (CPS) Photodynamic therapy (PDT) on fiber post disinfection bonded to radicular dentin in comparison to the conventional fiber post sterilant used. Materials and methodsFifty human permanent single-rooted premolars were utilized with the crown part sectioned using up to the cementoenamel junction. Root canal preparation was performed followed by canal obturation with gutta-percha (GP) and resin-based sealer. The post space was prepared using peso reamers leaving 4 mm at the apical part of the post space. Fifty glass fiber posts (GFP) were divided into five groups based on the surface disinfectant (n = 10). group 1: Autoclave sterilization (AS) group 2: chlorhexidine digluconate (CHX dig), group 3: CPS solution, group 4: 35% phosphoric acid (PA) gel, and group 5: No disinfection. Cementation was performed using dual-cure self-etch resin cement. Each tooth was sectioned and placed on the universal testing machine. Failure mode was analyzed using a stereomicroscope at 40x magnification. Statistical analysis was performed using one-way analysis of variance (ANOVA) and Tukey multiple comparison tests. (p = 0.05). ResultsIntragroup comparison analysis demonstrated that group 2 in which 2% CHX dig was used as a post-surface disinfectant revealed the highest bond integrity at all three levels. Group 5 where no disinfectant was used to decontaminate the post surface exhibited the lowest bond values. In all the investigated groups, PBS values showed a downward trend from coronal to the apical third of the post space. Group 1 in which AS was used to sterilize the fiber post and group 3 in which CPS was smeared to decontaminate the GFPs surface-displayed comparable outcomes of PBS to group 5 specimens at all three levels. (p > 0.05). ConclusionCHX dig and PA post-surface disinfection displayed a positive impact on bond strength with the radicular dentin. However, CPS and AS do not reveal any effect on the PBS when used for post-decontamination.

Retention of Manually or CAD/CAM-customized Fiberglass Posts Luted to Enlarged Root Canals with Different Resin Cements.

The aim of this laboratory study was to evaluate the pull-out force of a prefabricated fiberglass post (PP), relined fiberglass post (RP), or milled fiberglass post (MP) luted with Multilink N (MN), RelyX Unicem 2 (RXU2) or RelyX Ultimate (RU) to enlarged root canals. The thickness of the resin cements and the presence of voids in the resin cement film were observed. The root canals of 90 bovine incisors were enlarged, endodontically treated, and randomly divided into 9 groups (n=10) according to the post type and resin cement. The specimens were scanned using micro-CT to analyze the thickness of the resin cement and the presence of voids. The specimens were submitted to mechanical cyclic loading (500,000 cycles at 50 N load) and subjected to pull-out force testing. Two-way ANOVA and Tukey's test analyzed the pull-out force and resin cement thickness data. Kruskal-Wallis and Bonferroni tests analyzed the void scores. The interaction between factors (post × resin cement) was significant (p=0.0001) for the pull-out force. Higher pull-out forces were obtained for RP and MP compared to PP. The post factor was significant (p=0.0001) for resin cement thickness, which was higher for PP (1054 μm), followed by MP (301 μm) and RP (194 μm). More void formation occurred for PP, being less for RP, differing significantly among the posts. Post customization (RP and MP) decreased resin cement thickness and void formation, favoring a higher pull-out force. Resin cements requiring an adhesive application (MN and RU) favored higher pull-out force than self-adhesive resin cement (RXU2).

Extrusion bond strength of glass fiber post to radicular dentin after final irrigation using MTAD, EDTA, Pineapple peel extract, and Riboflavin

IntroductionThe present study aims to determine the effect of different post-space final irrigants ethylenediaminetetraacetic acid (EDTA), a mixture of Doxycycline citric acid and detergent (MTAD), Riboflavin (RF) and Pineapple peel extract (PPE) on the bond integrity of GFPs bonded to radicular dentin. Materials and methodsCrowns of forty human mandibular premolars teeth were sectioned up to cementoenamel junction CEJ. Root canal treatment was performed. Gates Glidden drills were used to retrieve gutta-percha from the canal. All the specimens were randomly divided into four groups based on the final irrigant used. Group 1 (NaOCl with EDTA), group 2 NaOCl+ MTAD, group 3 NaOCl+RF and group 4 NaOCl+PPE. Cementation of glass fiber posts (GFPs) was performed using self-etch dual-cure resin cement. Sectioning was performed using a slow-speed saw from the coronal, middle, and apical third under constant water irrigation. A universal testing machine was used to assess push-out bond strength (PBS) and failure mode was evaluated using a Stereomicroscope at 40x magnification. One-way analysis of variance (ANOVA) and Tukey multiple comparison tests were used for statistical analysis (p = 0.05). ResultsGroup 4 (2.5% NaOCl+ PPE) displayed the highest PBS at all three root levels (Cervical: 11.22 ± 0.74 MPa, Middle: 8.99 ± 0.97 MPa, and Apical: 6.00 ± 0.88 MPa). However, Group 1 (2.5% NaOCl+17% EDTA) demonstrated the lowest EBS (Cervical: 9.25 ± 0.17 MPa, Middle: 7.01 ± 1.84 MPa, and Apical: 4.41 ± 0.17 MPa). Inter-group comparison displayed that PBS to be comparable between group 1 and group 3 (2.5% NaOCl+ Riboflavin) (Cervical: 9.74 ± 0.41 MPa, Middle: 7.44 ± 1.18 MPa, and Apical: 4.21 ± 0.05 MPa) (p > 0.05). Whereas, group 2 (1.3% NaOCl+ MTAD) (Cervical: 9.32 ± 1.36 MPa, Middle: 7.17 ± 1.75 MPa, and Apical: 4.85 ± 0.19 MPa) and group 4 demonstrated comparable values of PBS (p > 0.05). ConclusionPineapple peel extract and a mixture of Doxycycline citric acid and a detergent when used as a final irrigant demonstrated better bond integrity of GFPs to radicular dentin at all three levels coronal, middle and apical.

Fracture resistance to fixed partial denture abutments with direct and indirect posts

The objective of this study was to evaluate the resistance to fracture of three-element fixed partial dentof glasstment teeth restored with glass fiber posts (GFP) and cast post-and-core (CPC) retainers. Herein, 60 bovine mandibular incisors were divided into two groups (n = 30) according to the retainer type in: 1) resin composite core reinforced with GFP; and II) CPC (Cu-Al). Each pair of roots consisted of one sample, simulating a three-element fixed partial denture. The structures of the fixed three-element partial dentures were made in Ni-Cr alloy. A conventional dual resin cement (RelyX ARC - 3M Espe, USA) was used for all cementation procedures. Samples were subjected to a compressive load onto an orifice at occlusal contact region of the pontic until collapse or fracture. Normal data distribution was verified by D'Agostino &amp; Pearson normality test. Unpaired t test was used for data analysis (α = 5%). The results showed that the the three-element fixed partial denture abutment teeth restored with composite resin cores retained by GFP presented higher fracture resistance compared to the ones restored with CPC (p=0.0009). In conclusion, the resistance to fracture of three-element fixed partial denture restored with resin composite core reinforced with glass fiber posts was higher to the one restored with post-and-core retainers.

Fracture resistance of endodontically treated teeth and restored with different fiber posts in distinct diameters

Objective: The aim of this in vitro study was to evaluate the fracture resistance of endodontically treated teeth restored with different intraradicular posts (carbon fibers, glass, or quartz) with varying post diameters (narrow, medium, or large). Methodology: One hundred and twenty bovine incisors were endodontically treated and the post space was prepared. The teeth were classified according to distinct diameters post space [Narrow (0.91-1.49mm), Medium (1.5-2.08mm), Large (2.09mm-2.67mm)] and randomly allocated to four restorative treatments: control (CO) - without post; and glass fiber (GF), carbon (CF) or quartz (QF) posts. The posts were cemented with dual-cure resin cement (Duo Link, Bisco, Schaumburg, United States) and the coronary portion was reconstructed with dual-cure resin composite (Bis-Core, Bisco, Schaumburg, United States). Fracture resistance values (N) were analyzed by two-way ANOVA and Bonferroni test (α=0.05). Results: The carbon fiber post (CF) was mechanical behavior similar to the other evaluated posts, regardless of the diameter. The control group (without post) showed the highest values of fracture resistance (1013.8 - 1127.2 N) in relation to the groups with the different evaluated posts (236.1 - 615.1 N). Within the same material, the diameter influenced the fracture strength only of the quartz fiber post, with the highest values for diameter large. Conclusion: A larger diameter only gives greater fracture resistance for QF; CF posts have similar resistance to other posts, regardless of diameter; and for large diameter, the type of post used does not differ in fracture resistance.

Stress distribution in restorations with glass fiber and polyetheretherketone intraradicular posts: An in silico analysis.

This study evaluated stresses generated at maxillary central incisor (21) root restored with lithium disilicate crown (LDC), and glass fiber (GFP) or polyetheretherketone (PEEK) post. 3D models created by computed tomographic image (i-CAT Cone Beam 3D Dental Imaging System) reproduced maxillary central incisor. Each model had prosthetic LDCs (2.0 mm thick) cemented to GFP or PEEK posts with dual resin cement. Different loads were applied to each model (cervical, incisal, axial, middle). At maximum principal stress, PEEK showed higher stress than GFP in all loads, but with qualitative similarity. At minimum principal stress, PEEK and GFP showed qualitative and quantitative similarities, except axial load. Maxillary central incisor restored with GFP or PEEK and LDC presented, in general, similar stress intensity and distribution for main occlusal loads. Only two of sixteen occlusal loads tested (cervical for maximum principal; axial for minimum principal) showed significant quantitative difference.

Impact of the removal of filling material from the post space with ultrasonic insert and magnification with a surgical microscope on the bond strength and adhesive interface of multifilament fiberglass posts onto flat-oval root canals

• Higher BS was found for MFPs compared to conventional fiberglass posts. • Ultrasonic tip filling removal results in higher BS and better adaptation of MFPs. • Highest BS was found for the use of ultrasonic tip with surgical microscopy.

Clinical approaches and removal of cast metallic posts for their replacement by the fiberglass posts: a concise systematic review

Introduction: A successful placement of an intraradicular post needs a good endodontic treatment. Consideration should also be given to the possibility of its future removal. Authors have shown that approximately 10% of cases of teeth indicated for endodontic retreatment require removal of intraradicular posts. Objective: To carry out a concise systematic review to analyze the reasons for replacing intraradicular posts, the most effective and used techniques for removing the metallic post, the manufacture of the fiberglass post, and the difference between the two types of posts. Methods: The present study followed a systematic review model, following the rules of systematic review – PRISMA. The search strategy was performed in the PubMed, Cochrane Library, Web of Science and Scopus, and Google Scholar databases. Results and Conclusion: A total of 112 articles were found. A total of 56 articles were fully evaluated and 18 were included in this study. Based on the objective and results found in the present study, the review demonstrated the main advantages and disadvantages of the clinical performance of cast metal posts and fiberglass posts, as well as the reason for switching from metal to fiberglass posts. Despite the wear caused by endodontic treatment, it is important to check the remaining dentin to choose the best retainer, observing the amount of this remaining structure, as it directly influences the selection of the post. Regarding the removal of the metallic pin, wear, ultrasound, and seizure/removal with some traction device are used. The replacement of the metallic post can opt for fiberglass posts because they have a greater advantage compared to the metallic post, mainly for aesthetics, the manufacturing technique is more agile, they do not generate risks of root fracture and if, for any eventuality, it needs to be removed. to portray the channel, the technique is smooth and easy.

Evaluation of three resin cements in the production of cone beam computed tomography artifacts in teeth with fiberglass posts

The present study analyzed the presence of artifacts in endodontically treated teeth restored with fiberglass posts (FP) cemented with different resin cements by means of cone beam computed tomography (CBCT) in order to evaluate the contrast-to-noise ratio (CNR). A total of 60 mandibular premolars were selected to assemble the phantoms in order to simulate a clinical situation. The teeth were allocated to 6 groups, in which G1, G2 and G3 were endodontically treated teeth restored with FP cemented with Nexus 3, Duo-Link, and Allcem Core resin cements, respectively; G4: endodontically treated teeth restored with FP; G5: teeth treated only endodontically; and G6: healthy teeth. Mean gray scale values were analyzed in the axial images of the cervical, middle and apical thirds of the post length. CNR analysis was conducted on all groups except G5 and G6. There was a statistically significant difference in the mean values of the middle third region regarding the groups analyzed (p=0.026). However, artifacts were observed in all studied groups. The statistical difference observed between the cervical and apical thirds when the groups were evaluated together did not characterize the absence of artifacts between the resin cements, even when only the FP was present. Consequently, the choice of a resin cement might be based on ease of handling, better working time, cost-effectiveness, activation modes, substrate conditions, and clinical aspects. In summary, image quality was found to be compromised by artifacts in the presence of FP through CBCT with or without the resin cements in the root canal.

Should a metal post always be replaced before a new indirect -restoration?

Before realizing a new indirect restoration on an endodontically treated tooth, present restorations and possible posts need to be assessed. In the case of a metal post, the mismatch in flexural modulus between the dentine and the post might increase the risk of a vertical root fracture. Is it therefore prudent to replace such a metal post, before the fabrication of a new indirect restoration? Two scenarios might be considered to answer this question. First, would a glass fibre post result in a lower risk of failure? Two systematic reviews of the literature comparing glass fibre and metal posts for the short term were contradictory. Second, is the occurrence of a vertical root fracture associated with the presence of a post? Such association could not be established either. On the basis of the current literature, there does not appear to be evidence to support actively replacing a metal post.

Assessment of push-out bond strength of post-surface pretreatment before salinization using hydrogen peroxide, aluminum trioxide, and natural photosensitizers to radicular dentin

ObjectiveThe study aimed to evaluate the effect of different post surface pretreatment methods i.e., 24% hydrogen peroxide (H2O2), riboflavin photosensitizer (RFP), curcumin photosensitizer (CP) and aluminum oxide (Al2O3), and silane only on the bond values of glass fiber post to resin cement Materials and MethodsFifty single-rooted human teeth were obtained and crowns were sectioned coronally to the cementoenamel junction (CEJ). Protaper universal file system was used for canal cleaning and shaping followed by obturation. Post space was prepared and all the posts were then randomly divided into five groups depending on the surface pretreatment used (n = 10). Group 1: 24% H2O2 + silane, Group 2: RFP + silane, Group 3: CP + silane, Group 4: Al2O3 + silane, Group 5: silane only. Post-surface treatment was followed by post-placement using a self-etch dual-cure cement Panavia F 2.0. Acrylic blocks were used to hold the specimens perpendicularly and all the samples were sectioned by slow-speed saw into coronal, middle, and apical third. The universal testing machine determines pushout bond strength and failure mode was analyzed by stereomicroscope. One-way analysis of variance (ANOVA) and Tukey multiple comparison tests were used to analyze data. ResultThe coronal section of group 4 (Al2O3 + silane) displayed the highest PBS (8.23±0.14 MPa). Whereas, an apical third of group 2 (RFP + silane) exhibited the lowest PBS (2.02±0.12 MPa). PBS values in samples in group 1 surface treated with 24% H2O2 + silane displayed comparable outcomes to samples in group 4 at all three levels (p>0.05). Samples in group 2 (RFP + silane) group 3 (CP + silane) and group 5 (Silane Only) demonstrated comparable PBS (p>0.05). ConclusionGlass fiber reinforced post-surface pretreatment method using hydrogen peroxide and aluminum trioxide along with silane improves push-out bond strength at all three levels (coronal, middle, and apical). The use of a silane coupling agent on glass fiber posts alone does not improve bond values. The practice of photosensitizer on post-surface needs to be investigated further.