Post Material Research Articles

Effect of different post materials and designs on upper central tooth torque and intrusion load: A finite element analysis study

The aim of this study was to examine the effects of post material type and the presence of ferrules on the torque and intrusion load of the upper central tooth using finite element analysis. The upper central tooth and surrounding tissues (cortical bone, cancellous bone, and periodontal ligament) were modelled in three dimensions using the Spaceclaim software. Five simulated models (SM) different modifications were made to this main model: metal cast post (SM1) and glass fiber post-core with zirconium crown and without a ferrule (SM2), metal cast (SM3) post and glass fiber post with a ferrule and zirconium crown (SM4) and only zirconium crown (SM5). In all five simulations, in order to simulate lingual root torque movement, a total load of 40grams was applied to the bracket slot as 20grams of force couples and in order to simulate intrusion movement, a load of 40grams was applied to the superior wall of the bracket slot. The stress caused by the applied loads on the root surfaces was determined using finite element analysis. Maximum principal stress (MPS) value was used in the comparison. The highest root surface MPS values for both intrusion and torque loads belonged to SM2 (3.864 and 0.379MPa, respectively). The presence of ferrules in both intrusion and torque loads reduced the stress by approximately half (from 3.864 to 2.004MPa). In all five models, the radicular area with higher stress was located in the cervical third on the lingual surface when both torque and intrusion loads were applied. The amount and localization of stress was affected by the type of post material. The variation in stress values between the materials remains within a safe range (0.099 and 3.87MPa), making both materials suitable for use under orthodontic forces.

The Effect of Surface Properties of Different Types of Post Materials on Fracture Type

Introduction and Aim Considering the advantages and disadvantages of different clinical situations, the surface characteristics of the post materials significantly affect the connection of the post material with dentin. In this study, the surface properties of PEEK posts, which are not yet widely used as post materials, were examined in terms of their effects on dentin bonding. Method 66 extracted upper central incisor-type human teeth that had undergone canal treatment with single and straight root canals were used. Posts were produced ) (n=11) from metal, fiber, and PEEK materials to form six groups (CP-0, CP-1, FP-0, FP-1, PP-0, and PP-1). The surface roughness of each post was examined by using a tactile profilometer. Zirconium full crowns, compatible with the central maxillary incisor anatomy, were produced for 66 samples with completed post-core production and polymerized using dual-cure resin cement (Monobond plus Vivadent). Subsequently, the samples were subjected to fracture strength testing at a 135-degree angle to the long axis of the tooth from the palatal side of the zirconium crown at a speed of 0.02 cm/min using a universal testing machine. After the test, the samples were classified into three groups based on the type of fracture: adhesive, cohesive, and mixed. One-way ANOVA and Pearson’s chi-squared tests were used for statistical analysis. Results The surface roughness value of the PEEK post group (1.42 ± 0.21) was significantly lower than that of the metal and fiber post groups. Although no significant difference was found in terms of the fracture type, the adhesive failure rate was higher in the PEEK post group (P

Effect of Different Surface Treatments on the Bonding Strength of Three Different Post Biomaterials to a Resin-Based Luting Agent.

The aim of this study was to evaluate how different post-surface treatments affect the ability of luting cement to bond three different dental post materials to a resinous surface. The study analyzed a total of 108 posts categorized into three main groups: stainless steel, cast, and fiber posts. Next, the core group was divided into four subgroups (n = 9) according to the type of surface treatment applied: no surface treatment (NS), silanization (SZ), sandblasting (SB), and sandblasting plus silanization (SBSZ). Stainless steel posts exhibited the lowest bond strength, whereas fiber posts demonstrated the highest shear bond strength. When it comes to surface treatments, dental post-surfaces treated with sandblasting have been found to exhibit the highest bond strength, outperforming other methods. Comparing all methods of surface modification, sandblasting with 50 um Al2O3 particles demonstrated the strongest connection.

Radiographic assessment of the quality of post and core restorations performed by general dental practitioners in Saudi Arabia

BackgroundDentists utilize various techniques and materials for post and core restoration of endodontically treated teeth, which remains a noteworthy health concern and can be addressed through interdisciplinary strategies to enhance outcomes. Therefore, this study aimed to evaluate the technical quality of the residual gutta-percha (GP) and posts by analysing the periapical radiographs of endodontically restored teeth. MethodsA total of 594 periapical digital radiographs were evaluated for tooth type, post material, post shape, design, diameter, length, residual GP, GP length, GP tapering, GP homogeneity, and final restoration. Frequency distribution and cross-tabulation of the variables were performed. ResultsMaxillary molars had the highest frequency of restorations, including posts, accounting for 27.4 %, followed by maxillary premolars (25.4 %) and maxillary anterior teeth (19.2 %). The prefabricated metallic posts were most commonly used (81.0 %), among these, 50.4 % were screwed posts. Tapered posts were the most commonly used (65.6 %). The percentage of posts with an acceptable length was 58.2 %. The most commonly used posts exhibited a width of one-third of the root diameter, accounting for 87.0 %. Suitable GP lengths were observed in 61.1 % of the restorations, and 62.8 % demonstrated adequate GP homogeneity. The findings of this study revealed that crown restoration accounted for 42.6 % of the studied sample. ConclusionsThe technical quality of the remaining GP after restoration was comparable to that of previous epidemiological investigations. However, the technical quality of the post was deemed suboptimal.

Pull-out behavior of cluster stud-post pouring UHPC connectors in prefabricated steel-concrete composite beam

The use of ultra-high performance concrete (UHPC) as a connection material for cluster studs of prefabricated steel-concrete composite beams can achieve higher connection strength and less space for reserved holes. However, in addition to bearing the shear force, the studs need to bear the pull-out force to counteract the vertical relative separation between the steel and concrete. The pull-out behavior for cluster stud-post pouring UHPC connectors is complex and has not been clarified completely. Thus, a total of 30 cluster stud pull-out tests in 10 groups were carried out in this study, and the interface type, length-to-diameter ratio of the stud, transverse spacing of stud group, dimensions of the reserved holes, and type of post pouring concrete were considered. The results showed that the pull-out behavior of the cluster studs was different from that of studs embedded in cast-in-place intact UHPC slabs due to the UHPC conical integrity having been reduced significantly by the old-to-new concrete interface. The rough groove interface and UHPC as a post pouring material significantly improved the pull-out capacity and stiffness of the cluster studs. The stud fracture belongs to ductile failure, whereas UHPC and normal concrete (NC) cone failures are brittle. The bearing capacity of the UHPC cone is observed to increase with the effective embedment depth of the stud, the transverse spacing, and the dimensions of the reserved holes. The angle of the UHPC conical failure surface is 70° based on 3D laser scanning. Finally, the theoretical equations for predicting the pull-out capacity of stud-post pouring UHPC connectors with a rough groove interface were proposed, and the critical length-to-diameter ratio of the stud was calculated for different combinations of stud and UHPC strength.

Strand Inventory Analysis of Post Tension in PT XYZ Using Discrete-Event Simulation Method

The development of connectivity infrastructure, particularly toll roads, is planned to continue expanding and reach 3,500 km by 2030. This signifies a positive outlook for the construction industry. This research conducted to analyse the management of post tension raw materials and determine the optimal policies using the discrete-event simulation method. Simulation scenarios were developed using the Arena application, taking into consideration the demand patterns for post tension work. The validation test results confirmed the capability of the base case model in accurately representing real-world conditions. Scenario development was carried out to influence the strand inventory pattern by incorporating reorder points and adjusting order sizes. Based on the scenario analysis, the most effective approach was found to be setting a reorder point of 3 tons and an order size of 5 tons. The implementation of this analysis successfully reduced the strand inventory by 58.78%. This research enables companies to optimize their inventory, reduce costs, and enhance operational efficiency. The findings contribute to the development of strategies that support sustainable growth in connectivity infrastructure in Indonesia.

Transformative Impacts of Tourism Advertising on Global Travel Industry

The reason for this paper is to show how advertising in creating and changing the travel industry on the planet. The travel industry advertising is the business control of pulling in guests to a particular area. Lodgings, urban areas, states, purchaser attractions, assembly halls and different destinations and areas related with customer and business travel, all apply fundamental advertising methodologies to explicit strategies intended to build visits. In the travel industry, showcasing incorporates deciding the extraordinary selling advantage or advantages one region has over its opposition. An objective may offer individuals hoping to join business and delight simplicity of movement to and from the space, adequate show lobbies and lodgings, fascinating nightlife, and exercises for grown-up accomplices and kids. The travel industry advertising utilizes a wide assortment of interchange as procedures and strategies to advance regions and objections. A conference hall may buy commercials in exchange magazines for meeting organizers and send post office-based mail materials to partnerships that hold occasions. They may put promotions in tennis or golf magazines to draw in those buyers. The travel industry objections assemble sites and spot advertisements in shopper distributions read by their objective clients. The offices of trade are engaged with advancing their zones for the most part and the organizations inside their spaces explicitly. This regularly incorporates offering potential guests bundles loaded up with pamphlets, rebate coupons and different materials

Fracture strength of fiber post with polyetheretherketone post: An In vitro comparative study

Abstract Aim: To assess and compare the fracture strength of polyetheretherketone (PEEK) post materials with fiber posts on endodontically treated maxillary central incisors. Materials and Methods: In this in vitro comparative study, two dental post materials were evaluated: fiber-reinforced post and PEEK post. Simple random sampling was done and 30 specimens were fabricated using extracted, decoronated, and endodontically treated maxillary central incisors (n = 15 for each group). Post-space preparation was done 5 mm short of the apex and restored with prefabricated fiber post (n = 15) and customized PEEK post (n = 15). Samples were mounted in a cold cure acrylic cylindrical block, at 45° angulation for testing the fracture strength using a universal testing machine. The data were analyzed and compared statistically, using an independent t test. Results: Mean fracture strength of the PEEK post was 65.79 kg and the fiber post was 59.32 kg with no statistically significant difference in the fracture strength between the two groups. Conclusion: Within the limitations of the study, it can be concluded that the PEEK post has similar mechanical properties to the fiber post and could be considered as an alternative to the fiber post having the advantages of being custom-made requiring conservative canal preparation with minimal dentin removal.

Evaluation of the Mechanical Properties of 3D-Printed Post and Core Systems.

To evaluate and compare the fracture resistance and elastic modulus of 3D-printed post and core systems and fiber posts and composite cores. Endodontic treatment was performed on 30 mandibular premolars, and post space preparation was performed. The teeth were then randomly divided into two groups (n = 15 per group): the 3D-printed (3DP) group and the fiber post and composite core (FPC) group. In the FPC group, fiber posts (Cytec Blanco 43.604, Hahnenkratt) were bonded with resin cement (RelyX U200, 3M), and the composite core dimension was standardized with a silicone index. In the 3DP group, the impression of the post space for each specimen was taken with pattern resin (Pattern Resin, GC America), and the coronal core was produced with the same silicone index. The impressions of the posts and cores were scanned, and then the custom post and core structures were fabricated from permanent crown resin material (Permanent Crown Resin, Formlabs) with a 3D printer (Form3B, Formlabs). Specimens were subjected to load tests with a universal testing machine (M500-25AT, Testometric). After fracture occurred, the fracture force and elastic modulus were calculated. The data were analyzed by independent sample t test (α = .05) Results: There was no statistically significant difference between the two groups in terms of peak fracture force (P = .626) and elastic modulus (P = .125), and no catastrophic root fractures were observed in either group. The fracture resistance of endodontically treated teeth was not significantly influenced by the post material. 3D-printed, custom-made resin posts were as effective as fiber glass posts with regard to fracture resistance.

Biomechanical Analysis of Mandibular Premolar Restored with Different Custom Post Core

Abstract Objective This study investigated biomechanical behavior of custom post core made of six different materials on the tooth with and without the ferrule under different occlusal load. Materials and Methods Three-dimensional models of mandibular first premolar, with and without ferrule, reconstructed from micro-computed tomography image are restored with different custom post core and zirconia crowns. By using the finite element analysis, von Mises stress shown in MPa was measured under simulated axial and oblique load of 200 [N]. To compare the stress distribution, six different custom post core materials were chosen: zirconia, Ni-Cr alloy, gold alloy, glass fiber-polyether ether ketone, polyether ether ketone, and carbon fiber-polyether ether ketone. Results Custom post cores with a higher modulus of elasticity showed higher measured stress in the posts, but less stress in dentin. Measured stress in custom post core under oblique loading was approximately three times higher compared with axial loading. Stress in custom post core and in dentin under both types of loads was slightly higher in teeth without ferrule effect. Conclusion The use of custom cast post cores made of different alloys is recommended in restoration of endodontically treated teeth, with extensive loss of tooth structure especially in teeth without ferrule effect.

Evaluation of the Fracture Resistance of Different Designs of All-Resin Post and Core Systems: An In Vitro Study.

Introduction There is a growing demand for post and core systems that offer both ease of use and efficiency. Recently introduced dual-cure build-up and post cement materials exhibit properties similar to dentin. The objective of this laboratory experiment is to compare the fracture resistance among three distinct post and core systems and identify the locations of failures within each group. Material and methods This in vitro experimental study involved 30 epoxy resin-based blocks (Endo Training Bloc J, Dentsply Sirona, Ballaigues, Switzerland) divided into three groups: The first group was a post space preparation and restoration with a fiber post (RelyX™ Fiber Post, 3M ESPE, Saint Paul, Minnesota, United States) 1.6 mm in diameter and 10 mm in length (Group A) where core build-up and cementation were performed using a dual-cure build-up and cement for endodontic post resin material (Core X Flow, Dentsply DeTrey, Konstanz, Germany). The second group was a post space preparation and restoration using a dual-cure build-up and cement for endodontic post resin material, 10 mm in length filled with resin but without fiber post placement (Group B). The third group was where post space and core were filled and restored with a dual-cure build-up and cement for endodontic post resin material, 5 mm in length and without fiber post placement (Group C). Subsequently, samples were mounted and tested using a universal testing machine (Instron, Canton, Massachusetts, United States), and the fracture site was located. Results Significant differences were identified among the three groups, indicating the impact of both post length and type on fracture resistance (p-value <0.05). Group B exhibited the highest mean compressive strength resistance and maximum load at 899.3330 (N), followed by Group C at 848.9690 (N) and Group A at 751.9620 (N). The predominant failures in the samples were core fractures or debonding of the core material. Conclusion All-resin posts demonstrated high fracture resistance, unlike fiber posts which displayed inferior fracture resistance.

Comparative Evaluation of Different Post and Core Systems in Maxillary Molar Endodontic Treatments: An Original Study.

Maxillary molar endodontic treatments require the right post and core system. This study tested cast metal, glass fiber with composite resin, carbon fiber with composite resin, and zirconia post and core materials. Sixty removed human maxillary teeth were randomly divided into four post and core material groups (n = 15 per group). The teeth acquired their post and core system after normal endodontic treatment. Fracture resistance, cyclic fatigue resistance, and microleakage analyses were statistically assessed. The zirconia post and core material had the highest fracture resistance (mean: 900 N), followed by carbon fiber with composite resin, cast metal, and glass fiber with composite resin. Zirconia had the highest mean cycles to failure (120,000), followed by carbon fiber with composite resin (100,000), cast metal (110,000), and glass fiber with composite resin (90,000). Zirconia had the lowest mean microleakage score (1.8), and glass fiber with composite resin, the highest (3.0). The zirconia post and core material outperformed the others in fracture resistance, cyclic fatigue resistance, and sealing. The cast metal has better fracture and cycle fatigue resistance than glass fiber with composite resin. These findings help doctors choose maxillary molar endodontic post and core materials.

Evaluation the Fracture Resistance of Endodontically Treated Teeth Restored With Different Post and Core Materials

Widespread use of prefabricated post that provides retention and support for core and the final crown has caused manufacturers to produce different types of post materials. The aim of this study was to evaluative the fracture resistance of two types of post materials and two types of core material. Forty extracted human mandibular premolar were selected. After root canal preparation and obturation with gutta percha the roots were divided into two groups according to the type of post material, group F restored with fiber post and group T restored with titanium post then each group was subdivided into two subgroup according to the type of core materials which include composite and amalgam restorative materials. Then all the teeth were subjected to compressive load at 130o angle from the horizontal plan at a 5mm/min crosshead speed until fracture. Results showed that there was significant different between groups in term of fracture loads (P= 0.0156). Also the fracture loads of teeth restored with titanium post and composite core has highest mean fracture load (812N), whereas teeth restored with fiber post and amalgam core demonstrated the lowest mean fracture load (643.1N). The study concluded that the teeth restored with metal titanium post were more fracture resistant than those restored with fiber posts. But the combination of a fiber post and composite core has the favorable mode of fracture that considered reparable, while considered unfavorable when restored with titanium post.

Influence of the metal post material, tooth location in the dental arch, and metal artifact reduction tool on vertical root fracture diagnosis in cone beam CT.

This study aimed to evaluate the influence of the metal post composition, tooth location in the dental arch, and metal artifact reduction (MAR) on vertical root fracture (VRF) diagnosis in cone beam computed tomography (CBCT). Twenty-two unirradicular premolars (12 sound and 10 fractured) and two alveolar sockets of a mandible (anterior and posterior regions) composed the sample. CBCT scans of each tooth with a metal post placed into the root canal-silver-palladium (Ag-Pd), cobalt-chromium (Co-Cr), or nickel-chromium (Ni-Cr)-were individually acquired for each mandibular region, and two conditions of MAR, using a OP300 device (Instrumentarium, Finland). Images were assessed by five evaluators independently for VRF detection. Diagnostic values were calculated and compared among all groups using multi-way ANOVA with Tukey post hoc test to investigate the effect of post material, anatomical region, and MAR on VRF diagnosis (α = 0.05). Values of area under the receiver operating curve and specificity were not influenced by the studied factors (p > 0.05). Sensitivity was influenced by the MAR in both mandibular regions (p < 0.05). In the anterior region, sensitivity values increased when the MAR was enabled, regardless of the metal post material (p < 0.05). Similar behavior was noticed in the posterior region for Ni-Cr (p < 0.05) but not for Ag-Pd and Co-Cr posts (p > 0.05). The MAR improved the sensitivity in VRF diagnosis for all tested metal posts in the mandibular anterior region and for the Ni-Cr post in the mandibular posterior region. Therefore, for images obtained in the OP300 CBCT device, activation of the MAR is suggested in these cases.

A microcomputed tomography analysis of adaptation in premolars with flared root canals restored with different digitally custom fabricated post materials

Statement of problemPreserving and strengthening the remaining tooth structure of compromised flared root canals after endodontic treatment is challenging. PurposeThe purpose of this in vitro study was to compare the adaptation of milled polymer- infiltrated ceramic, fiber-reinforced composite resin, and high-performance semicrystalline thermoplastic resin posts as used to restore mandibular premolars with flared root canals. Material and methodsForty sound mandibular premolars were randomly divided into 4 groups: custom Vita Enamic (CV), custom fiber-reinforced composite resin (CF), custom polyetherketoneketone (CP), and prefabricated fiber (RF) posts. After endodontic treatment, each tooth was sectioned 1.5 mm occlusal to the cementoenamel junction. Then, the post space was prepared and flared, except the RF group, to a depth of 9 mm. The post space in RF group was prepared with a post drill. For the CV, CF, and CP groups, the posts were milled, finished, and cemented to their corresponding teeth. Each tooth was scanned using a microcomputed tomography device, and the reconstructed images were analyzed in mesiodistal, buccolingual, and horizontal planes. The cement thickness, cement volume, and volume of voids were measured. The data were analyzed using 3-way ANOVA (cement thickness) and 2-way ANOVA (cement volume and voids volume) tests followed by the post hoc Tukey test (α=.05). ResultsThe 3-way ANOVA test revealed a significant interaction (P<.001) between material type, section, and surface on the cement thickness. The mean cement thickness in the RF group was significantly higher than in the CV group (P=.001) and CF group (P=.005). The least mean cement thickness was at the apical section followed by the cervical and middle sections. Regarding cement volume, the 2-way ANOVA test showed statistically significant interaction between material type and section. The mean cement volume in the RF group was significantly lower than in the CV group (P=.001), CF group (P=.001), and CP group (P=.001). The highest mean cement volume was in the cervical section followed by the middle and apical sections. The 2-way ANOVA test showed statistically significant interaction (P<.001) between material type and section on the volume of voids. Significant differences were found between the mean volume of voids at the cervical and middle sections (P=.001) and the cervical and apical sections (P=.002). ConclusionsCompared with prefabricated fiber posts, digitally fabricated polymer-infiltrated ceramic and fiber-reinforced composite resin posts had a thinner cement layer with minimal thickness at the apical section. The digitally fabricated posts had higher cement volume, especially at the cervical section, than prefabricated fiber posts. High volumes of voids were related to the cervical section of all tested posts.

Fracture strength of cad-cam milled polyetheretherketone (PEEK) post-cores vs conventional post-cores; an in vitro study.

The aim of this study was to compare the fracture strength and fracture modes of post-cores produced with CAD-CAM from modified polyetheretherketone (PEEK) materials with other custom-produced post-cores. Sixty human mandibular first premolars with equal root sizes were used. The teeth were divided into six groups (n = 10), and root canal treatment was performed. The teeth were separated from the roots over 2 mm from the cemento-enamel junction. As a result of the decoronation process, a 1 mm wide shoulder line was obtained for all teeth. For the fracture strength test, 10 mm deep post spaces were created on the teeth with a 1.6 mm diameter driller. Post-core groups consisted: everStick®glass fiber post-core (Group GF), zirconia post-core (Group Z), metal (Cr-Co) post-core (Group M), PEEK post-core without filler (Group UP), PEEK post-core with 20% TiO2 Filler (Group TP), and post-core with 20% ceramic filler (Group CP). Following the application of posts to post spaces, copings were created and cemented on the samples. With the universal tester, a force was applied to the long axis of the tooth with a slope of 135°. The mean fracture strength (N) between the groups was statistically evaluated using one-way ANOVA, and pairwise mean differences were detected using post hoc Tukey's HSD test among the groups. According to the results of the statistical analysis, a significant difference was found between the groups in terms of mean fracture resistance (p <0.05). Group Z (409.34±45.72) was significantly higher than Group UP (286.64±37.79), CP (298.00±72.30), and TP (280.08±67.83). Group M (376.17±73.28) was significantly higher than Group UP (286.64±37.79) and Group TP (280.08±67.83). There were no statistically significant differences between the means of the other groups (p >0.05). Among all the groups, Group Z exhibited a higher prevalence of repairable failure modes, while the rest of the groups predominantly experienced irreparable failure modes. In our study, zirconia and metal post-core samples showed higher average fracture strength values than PEEK post-cores groups. Repairable failure modes were more common in the zirconia post-cores, whereas the opposite was observed in the other groups. Further experimental and clinical trial studies are needed before PEEK materials can be used as post materials in the clinic.

Factors Influencing Vertical Radicular Fractures in Teeth Supported by Metallic Dental Core: A Scoping Review.

The aim of this work is to conduct a literature review to highlight all the parameters involved in sub-prosthetic radicular fractures of teeth supported by metallic dental core. The following research was performed among published studies over the last 10 years in two PubMed/Medline and Scopus and supplemented by manual searching within the bibliographies. The search was restricted to publications in English and French. Out of the 1464 articles initially identified, 18 studies met our inclusion criteria and were subsequently included in the literature review. These consisted of eight Finite Element Analysis Studies, two Retrospective Studies and one Randomized Controlled Trial. The results of this review show that radicular fractures are influenced by several variables, including predisposition, with maxillary premolars and mandibular molars being the most commonly affected teeth. Intracanal preparation can induce crack formation, leading to localized high stress concentrations. Increased ferrule height to 2 mm significantly enhances dental fracture resistance. Using high modulus of elasticity alloys results in nearly complete stress transmission to dentin due to their limited deformability and absorption capacity. The highest fracture resistance is achieved when posts are sealed using resin-modified glass-ionomer cement. Longer posts may be preferable to prevent vertical fractures. Additionally, occlusal factors, through repetitive stresses, contribute to crack propagation from surface defects, a phenomenon termed fatigue fracture. These findings have significant implications. Practitioners should be aware of the predisposition of certain teeth, the importance of preserving the ferrule effect, the choice of root post materials, post Cement Material and the role of occlusal forces in managing and preventing vertical root fractures.

Influence of Post Length, Post Material, and Substance Loss on the Fracture Resistance of Endodontically Treated Teeth: A Laboratory Study

To evaluate the effects of post length, post material, and substance loss on the fracture resistance of endodontically treated mandibular premolars. A total of 96 extracted human mandibular first premolars were endodontically treated and divided into 12 test groups (n = 8 each) based on the number of residual walls (one/two), post material (glass-fiber/titanium), and post length (5 mm, 7.5 mm, and 10 mm). After luting the posts, specimens received a composite resin core and a crown preparation with a 1.5-mm ferrule. Cast cobalt-chromium crowns were cemented using glass-ionomer cement. After 1,200,000 chewing cycles with a load of 49 N and simultaneous thermocycling (5°C to 55°C), specimens were quasi-statically loaded at 30 degrees to the longitudinal axis of the tooth until fracture. Fracture loads were analyzed using three-way, two-way, and one-way ANOVA (α = .05). Fracture modes were examined under a stereomicroscope (×25 magnification) and recorded. The mean ± SD fracture loads ranged from 642 ± 190 N (one wall, glass fiber, 5 mm) to 1,170 ± 130 N (two walls, titanium, 7.5 mm). The mean fracture load of titanium posts was significantly higher than that of glass-fiber posts (P < .001), and the 7.5-mm post length exhibited significantly higher fracture loads than groups with 5-mm and 10-mm post length (P = .008). Teeth restored with titanium posts revealed considerably higher fracture resistance than teeth restored with glass-fiber posts, especially if 7.5-mm-length posts were used.

Sharing, curation and metadata as essential components of the data management plan

This paper stresses the critical importance that data management plans actually be data management and sharing plans, that encourage data-sharing at the early stages of research; that indicate that data must be made as open as possible (and as closed as necessary); and that specify a minimum level of curation and collection of essential metadata. The author stresses that fact that it is no longer sufficient to post material openly and hope that others will be able to make use of it. The use of metadata and careful data curation of the data are essential to facilitate the discovery and successful re-use of data.

Fracture resistance of endodontically treated teeth, restored with two post-core systems in different post space diameters (in vitro study)

BackgroundFracture resistance of post-core restoration depends on the design of the post, post diameter, post length, the type of adhesive cement used along with material of the core. Despite the different studies concerning the effect of post space diameter on the fracture resistance of endodontically treated teeth, more information regarding fracture resistance and the effect of different post space systems/materials and diameters is required.Aim of the studyThis study aimed to evaluate fracture resistance of endodontically treated teeth, restored with two post-core systems in different post space diameters.Materials and methodsTwenty freshly extracted maxillary central incisors were collected for this study. They were randomly divided into four groups according to intracanal post and its diameter. Group GN (glass-fiber post of 10-mm length and 1.3-mm diameter with composite core), group GW (glass-fiber post of 10-mm length and 1.75-mm diameter with composite core), group ZN (custom-made zirconia one-piece post-core of 10-mm length and 1.3-mm diameter) and group ZW(custom-made zirconia one-piece post-core of 10-mm length and 1.75-mm diameter).Fracture resistance for all samples was evaluated using the universal testing machine under a static load. The data was collected and statistically analyzed using One-Way ANOVA test. Modes of failure were assessed using stereomicroscope for each group.ResultsThe highest mean fracture resistance was recorded in group GW (638.7 ± 285.1 N), followed by group ZW (598.5 ± 127.6 N), then GN group (442.8 ± 65.38 N). The lowest mean fracture resistance was recorded in group ZN (435.3 ± 117.3 N). One-Way ANOVA test revealed that there was no statistically significant difference in fracture resistance values among the groups.ConclusionPost space diameter had an impact over the fracture resistance of endodontically treated teeth. Modulus of elasticity of post material had a major effect on the fracture resistance and mode of failure along with the restorability of the restored tooth. However, there was no statistically significant difference among the tested groups.