Post Dentin Research Articles

Comparative evaluation of dental integrity using three computer-aided design/computer-aided manufacturing customized post systems

Background Endodontically treated teeth (ETT) are considered structurally compromised due to significant changes in their biomechanics.The purpose of this in vitro study was to evaluate fracture resistance using three computer-aided design/computer-aided manufacturing (CAD/CAM) customized post systems. Methods Forty extracted intact maxillary central incisors were used in the study, and the teeth were endodontically treated and randomly divided into four equal groups (n = 10): control group without any post and accessed cavity was restored with direct composite restoration. Test groups were prepared for a post and restored according to the material type. The posts and cores were fabricated with computer-aided design/computer-aided manufacturing technology using titanium, vita enamic, and biological dentin materials. The posts were luted using self-adhesive resin cement, and then, zirconia crowns were fabricated, cemented, teeth in all groups were mounted to universal testing machine and subjected to compressive load in Newton at crosshead speed 0.5 mm/min. Results Control group exhibited the highest fracture resistance (727 ± 172.05) followed by biological dentin posts with mean value (712.29 ± 298.58) then group titanium posts with mean value (678.59 ± 132.83) and the least fracture resistance was for group vita enamic with mean value 331.84 ± 74.27. Regarding to fracture favorable it was significantly higher in vita post group than titanium post group (70% vs. 30%) and control group (70% vs. 10%) but it was significantly higher in biological dentin group than titanium group (80% vs. 70%). Conclusion According to type of material, teeth restored with the biological dentin posts showed highest fracture resistance followed by titanium posts, the least fracture resistance was vita enami posts.

Comparison of the Pull-Out Resistance of Grossly Decayed Primary Anterior Teeth Restored With Two Different Intracanal Posts: An In Vitro Study

Background Severely damaged primary anterior teeth that require pulp therapy present a high risk of failure due to the loss of tooth substance, resulting from pre-existing decay and endodontic therapy. The ideal post material should have physical and mechanical properties similar to those of dentin. Another concern in restoring endodontically treated primary teeth is the need to find a material that can resorb similar to the natural tooth structure as a part of the exfoliation process, allowing normal eruption of permanent successors. Accordingly, there is no such material other than dentin itself. The introduction of biological dentin posts offers an excellent alternative for restoring such teeth. This study aimed to assess the effect of using dentin posts on the pull-out resistance of endodontically treated primary anterior teeth in comparison to glass fiber posts. Methodology A sample of 30 primary anterior teeth was collected from the outpatient clinic of the Pediatric Dentistry Department, Faculty of Dentistry, Damascus University. A total of 15 freshly extracted permanent teeth with single roots were also collected from the outpatient clinic of the Maxillofacial Surgery Department, Faculty of Dentistry, Damascus University. The roots of the permanent teeth were used to prepare 30 dentin posts using a CAD-CAM machine. After receiving proper endodontic treatment, the primary teeth were divided into two groups (15 teeth in each group). The first group was restored with dentin posts, and the secondwas restored with glass fiber posts, with the posts measuring 3 mm in length for both groups. Pull-out resistance testing was performed using a Testometric machine. Results The arithmetic mean of the forces applied in the glass fiber posts group was 153.2 ± 39.12 N, while the arithmetic mean of the forces applied in the dentin posts group was 156.7 ± 39.78 N. The data were analyzed at a 95% confidence interval using the independent Student's t-test. There were no statistically significant differences in pull-out resistance between the two groups. Conclusions Dentin posts showed a little increase in pull-out resistance than glass fiber posts. Therefore, the use of dentin posts as intracanal retention in primary anterior teeth is a successful alternative for composite posts.

Comparing the Fracture Resistance of Dentine Posts and Glass Fiber Posts in Primary Maxillary Incisors: An In Vitro Study.

Background/purpose An ideal post material should have physical and mechanical properties similar to dentin. Another problem when restoring primary teeth that have undergone root canal treatment is the availability of materials that are resorbed in the exfoliation process in a manner similar to the structure of the natural tooth, allowing the normal eruption of a permanenttooth. This study aimed to evaluate the effect of using dentine posts on the fracture resistance of endodontically treated primary incisors in comparison to glass fiber posts. Materials and methods The study sample consisted of 30 extracted primary maxillary incisors that were randomly distributed into the following two groups: group I (experimental, n=15), which was restored with dentine posts; and group II (control, n=15), which was restored with glass fiber posts. Initially, 10 extracted single-root permanent teeth were collected to prepare 20 dentine posts using a computer-aided design-computer-aided manufacturing (CAD-CAM) machine. Then, the crowns of maxillary primary incisors were cut and the canals were prepared and filled. Then the preparation for a post was made using Gates Glidden drills, and the posts were placed with an extension of 3 mm within the canal in both groups, then the crown was built and the teeth were placed within acrylic cubes and subjected to 500 thermocycling. Fracture resistance was recorded using a Testometric machine (Rochdale, England: Testometric Co. Ltd.). Data were analyzed using an independent Student's t-test. Results The dentine posts group showed greater fracture resistance (246.3 N) than the glass fiber posts group (206.3 N). A statistically significant difference (p=0.004) was found between the two groups in favor of the dentine posts group. Conclusion Based on this in vitro study, the dentin posts used in restoring severely decayed primary maxillary incisors showed greater fracture resistance than glass fiber posts. Therefore, the use of dentin posts as intra-canal stabilizers in maxillary primary incisors is a good alternative for glass fiber posts.

Efficacy of Different Dentin Posts for the Treatment of Primary Anterior Teeth (An In vitro study)

ABSTRACTIntroduction: Early childhood Caries is a distressing situation for patients andparents and pediatric dentists. Aim: current research was carried out to evaluatefracture resistance and bond strength for different types of dentin posts compared tofiber posts. Materials and Methods: This Current in-vitro study was conducted on48 extracted primary incisors. Samples were split randomly into 4 groups of 12 foreach group. Group-I (fiber posts 6mm length, 1.4mm diameter), Group-II (dentin posts6mm length, 1.4 diameter), Group-III (dentin posts 8mm length, 1.4mm diameter),Group-IV (dentin posts 8mm length, 1.6mm diameter). Each group was furthersubdivided into two subgroups (6 for the Push-Out bond strength test and 6 for thefracture resistance test using Universal Testing Machine). Results: It was observedin the fracture resistance test that, Group III showed the highest fracture resistancemeans (140.678±11.98) followed by Group IV (131.38±7.03), Group-II (94.23±9.84),and finally Group-I that showed the lowest fracture resistance means (80.465±2.82).Push-Out bond strength test revealed that the highest mean value with Group-IV(8.653±1.49), followed by Group-II (6.08±2.25) and Group III (5.67±2.44) have nostatistically significant difference between them, while the lowest mean value was forGroup-I. Conclusions: Dentin posts showed increased fracture resistance and bondstrength more than fiber posts. The use of dentin post as intra-canal retention in primaryanterior teeth possesses the most important advantages over the fiber post. Therefore,biological dentin post is a successful alternative for fiber post.

A three dimensional finite element analysis of fiber post and dentin post in permanent maxillary central incisors: An in-vitro study

: Endodontically treated teeth are generally weakened as a result of loss of tooth structure due to decay, previous restorative procedures and endodontic access preparation. Ideal coronal reconstruction of endodontically treated tooth is still a challenge for restorative dentistry. Post and core system is a widely used method for treatment of structurally weakened teeth. Two extracted, caries-free maxillary central incisors with straight root canal were collected and mounted. Post space preparation were done and restored with fiber post and dentin post respectively. The model is simulated using the software “Creo” and this data is then transferred to software “Hypermesh” to create a Finite Element model i.e., a mesh of nodes and elements. This mesh is programmed to contain the material properties which defined how the structure will react to loading conditions at different angles. The Analysis is carried out using the Ansys software.: The FEA results showed that the Dentin post have better fracture resistance. The comparison between fiber and dentin posts exhibited a better stress resistance of dentin post over fiber post. Further research in this regard is required to support the findings of this study results.

Resistance to fracture of intraradicular posts made of biological materials

BackgroundThe aim was to analyze the fracture resistance of human teeth treated endodontically and restored with posts made of bovine dentin, human dentin, or glass fiber, and to evaluate the fracture pattern.MethodsCylindrical posts of 1.5 mm in diameter cemented to the roots of human maxillary canines presented a length of 15 mm, cervical diameter of 5–5.5 mm in the mesiodistal direction, and 7–7.5 mm in the vestibule-palatal direction. The groups studied were: Group I—10 glass fiber posts; Group II—10 human dentin posts; Group III—10 bovine dentin posts (self-adhesive resin cement); and Group IV—10 bovine dentin posts (resin-modified glass-ionomer cements). The coronal part of tooth was restored with a standardized core build-up using composite. All of the groups were submitted to a compression force test and the resistance to fracture was verified using a universal testing machine. The fracture pattern was likewise evaluated.ResultsThe values of resistance to fracture were: 723.3N in group I, 561.5N in group II, 556.6N in group III, and, 613.27N in group IV. However, no statistically significant difference was observed among the groups. The fractures in groups I and II were most commonly found in the middle/apical third and were considered irreparable. For restored teeth in group III, half of the fractures appeared in the cervical third and were reparable. In group IV, all of the fractures were reparable, with the majority in the cervical thirds.ConclusionBovine dentin can be used as intraradicular post to substitute human dentin and glass fiber posts. The greater the malleability of the post, the greater the chances of survival of the teeth when subjected to fracture testing.

Introduction of a new teaching concept for dentin post preparation with 3D printed teeth.

The preparation for dentin posts is difficult and hard to learn. There are currently no reproducible simulation models to train this clinical procedure. The purpose of this study was the design, feasibility and evaluation of a three-dimensional (3D) printed tooth model for the pre-clinical teaching of students. A printable tooth was designed and printed by a stereolithographic printer. A total of 48 fourth-year dental students in the first clinical course in prosthodontics were trained in a voluntary hands-on course on 4 similar printed teeth. The students used standard model teeth and real-teeth models during their education. They had experience in caries removement and root canal treatment on real patients. Root perforations were counted for every attempt. The different benefits of the 3D printed tooth were evaluated by a questionnaire using German school grades from 1 (best) to 6 (worst). The overall rating of the printed tooth was Ø1.9±0.3. The item "suitable exercise option" was rated Ø2.0±0.8, and the teeth were "easy to use" Ø1.9±0.9. The item "realistic approach to dentin post preparation" was rated Ø2.1±0.8, and the teeth showed the "shortcomings at a root perforation" Ø1.5±0.6. The students reported to have much more motivation and enthusiasm to improve their skills with the printed teeth Ø2.1±0.9. They had a strong desire to include these teeth in their pre-clinical education before the first patient treatment Ø1.6±0.8. The success rate of the dentin post preparation was significantly better for the second 25% (P=.047) and fourth 48% (P=.04) attempt. The feasibility of this teaching concept was confirmed. The students had the possibility to learn a correct dentin post preparation on a printed tooth model. The learning effect with this tooth model was rated as good to very good by the questionnaire.

Does Sterilization Affect the Push Out Bond Strength of Experimental Dentin Posts?

The purpose of this preliminary study is to evaluate the push-out bond strength (PBS) of experimental dentin posts (EDPs) obtained from human and bovine teeth sterilized by autoclaving and gamma radiation. Eighty-four mandibulary premolars were obturated and divided into three post groups: the glass fiber group (Fb) human EDP group (Hm) and the bovine EDP group (Bv). Three subgroups (n=12) were obtained for each EDP groups according to the sterilization methods; no sterilization (Cnt), steam autoclaving (Aut), and gamma radiation (Rad) a total dose of 25 kGy. All posts were cemented to root canals using a dual cured resin cement (Panavia SA). After the micro slices (1mm in thickness) were obtained of each subgroup, PBS test was performed. Data were analyzed using two-way ANOVA and Tukey’s multiple comparison tests (α=.05). The post type and sterilization method was significantly effective on the PBS values according to the ANOVA (P<.001). No sterilization apllied EDP groups showed significantly higher PBS values than the sterilized groups (P<.001). Bv_Cnt (9.42 ±1.31) showed significantly lower PBS values than both Fb (12.36 ±1.54) and Hm_Cnt (11.06 ±1.38) groups (P<.001). Both steam autoclaving and gamma radiation affect the PBS values and fracture modes of EDPs negatively. The bovine EDPs are not as effective as human EDPs with regard to the PBS to the root dentin.

Development and characterization of biological bovine dentin posts

This study aimed at evaluating the use of biological dentin post (BDP), achieved by milling bovine root, through the analyses of mechanical and optical properties. BDPs were compared to a glass fiber post (GFP) in the following tests (n = 10): a) elastic modulus (E) and flexural resistance (σ) by three point bending test; b) fracture resistance (FR) by compressive load at 45° and failure pattern; c) light transmitting (LT) ability and their influence on the resin cement's degree of conversion (DC%); d) bond strength (BS) by push-out test and failure pattern. Bovine teeth were decoronated and root length was standardized at 14 mm. The canals were prepared and irrigated with 2.5% NaOCl. GFP's surface was conditioned by 1 min immersion in 24% H2O2 solution before silanization. After root embedment, the root canal walls and the BDP's surface were hybridized (H3PO4 37% + self-cured adhesive) for FR and DC% analyses. Posts were fixed into the root canals using a conventional dual resin cement. For BS test, both posts were luted using the conventional and the self-adhesive cementation. A universal testing machine (EMIC DL2000; 1 mm/min) was employed for the mechanical tests (E, σ, FR and BS). For the LT analysis, opaque polyethylene discs were transfixed by the posts, leaving 10 mm of the posts’ apical section for measurements. Posts’ cervical portion was irradiated (800 mW/cm2) and a spectrometer recorded the number of photons transmitted to previously chosen lateral post regions and at the apical tip. The resin cement DC% was evaluated in several sites of the cement film. After normal distribution were checked (Shapiro-Wilk test), data were submitted to ANOVA (5%) and Scheffe post-hoc test (5%). Results showed that: a) E: BDP > GFP; b) σ: BDP < GFP; c) RF: BDP < GFP; d) LT could not be observed for BDP. For GFPs, the greatest number of photons was observed at the post apical tip. An exponential decay was observed from the cervical to the apical post region; e) resin cement DC% was statistically similar at all points of measurements for both posts; and, f) BS: BDP = GFP, regardless the adhesive protocol used. It was concluded that: a) teeth restored with BDP exhibited lower fracture resistance than those restored with GFP; b) resin cement DC% was not influenced by the light transmitting ability of the post; c) the retention provided by the BDP was similar to the one provided by GFP, independently of the luting protocol.

Effect of Application Mode on Bond Strength of Adhesively Luted Glass-fiber Bundles Inside the Root Canal.

The aim of the present study was to measure the bond strength of adhesively luted glass-fiber bundles inside the root canal with respect to the application procedure in comparison to conventional solid glass-fiber posts. 104 human anterior teeth were endodontically treated, root filled and divided into 8 groups (n = 13). After post space preparation, fiber bundles consisting of 6 and 12 glass fibers, respectively, were luted adhesively with a multi-mode adhesive (Futurabond U; Voco, Cuxhaven, Germany) and a dual-curing composite (Rebilda DC, Voco) with the following application modes into the root canal: (1) direct application with tweezers, (2) distribution of the fibers using a spreader, (3) application of ultrasound after insertion of fibers. Two different solid posts (Rebilda DC, Voco; and DentinPost, Komet, Lemgo, Germany) were used as controls. Roots were sectioned into 6 slices per root (thickness 1 mm). Bond strengths were measured using thin-slice push-out tests for 3 slices 24 h after post insertion and for 3 slices per sample following thermocycling (TC) for 6000 cycles and storage in 0.9% NaCl for 6 months. Homogeneity of the slices was analyzed using a stereomicroscope and, for representative samples, micro-computed tomography (µCT). Mean push-out bond strengths (MPa) were significantly affected by post system (p < 0.0005) and location inside the root canal (p = 0.004) but not by application mode (p = 0.544) or TC (p = 0.098; repeated measurement ANOVA). Fiber bundles consisting of 6 (13.2 ± 4.7) and 12 fibers (14.5 ± 4.3) revealed bond strength comparable to that of Rebilda Post (13.67 ± 3.2) but significantly higher than that of Dentin Posts (8.7 ± 3.02). Inhomogeneities were detected among 35.5% to 43.1% of the fiber-bundle samples, irrespective of number of fibers and application mode, and among 24.4% to 27.3% of the solid posts (p = 0.010; chi-squared test). µCT revealed voids inside the composite bulk between the fibers as well as between composite and dentin of adhesively luted fiber bundles. Adhesively luted fiber bundles achieved bond strengths comparable to those of solid fiber posts for one investigated post type, and even higher values compared to another post type. Inhomogeneities were frequently detected irrespective of application mode.

Root canal reconstruction using biological dentin posts: A 3D finite element analysis.

Background. Several types of post have been developed for clinical use. A biological dentin post obtained from an extracted tooth eliminates the problems arising from material differences and reduces the fracture rate in teeth undergoing root canal treatment. This study used finite element analysis to compare a biological dentin post with posts made of two different materials. Methods. Three 3D models of the upper central incisor were created, and stainless-steel, glass fiber and biological dentin posts were applied to these models. The restoration of the models was completed by applying a composite as the core structure and a ceramic crown as the superstructure. Using finite element stress analysis in the restoration models, a 100-N force was applied in the vertical and horizontal directions and at a 45º angle, and the suitability of the biological dentin post was evaluated by comparing the data. Results. Under the applied forces, the greatest stress accumulation was seen in the models with the stainless steel post. Because the stainless steel post was more rigid, stress forces accumulated on the surface instead of being transmitted to the tooth tissue. In the models with the glass fiber and biological dentin posts, the post material responded to the stratification in tandem with the dental tissue and did not cause excessive stress accumulation on the tooth or post surfaces. Conclusion. The results showed that biological dentin posts prevent the accumulation of stresses that might cause fractures in teeth undergoing root canal treatment. In addition, the physical compatibility and biocompatibility of a biological dentin post with the tooth imply that it is a good alternative to the types of post currently used.

Stress distributions in maxillary central incisors restored with different high-stiffness post models: 3-D FEA

Background: Dental root posts are recommended for endodontically treated weakened teeth.Objectives: The present computational FEA study aims to evaluate the effect of material and design of the post on the stress distribution under load in different root canal shapes of endodontically treated maxillary central incisor (MCI).Methods: Three-dimensional models of (MCI) were created by using CAD modeling software and divided into two groups. Group-I comprised five models of a weakened root restored using different post materials (stainless steel, titanium, gold-alloy, Ni-Cr, and zirconium). Group-II: involved four models of (MCI) with two different root canal shapes (small and wide) restored using cylindrical (C-Post) and two-stage tapered (T-Post) posts. Each tooth model was subjected to a 100 N oblique load at the palatal surface of the crown. Von Mises equivalent stresses on dentin and post, as well as shear stresses on the post cement, were evaluated.Results: In Group-I: Ni-Cr produced the lowest stress values on the dentin, where titanium and gold-alloy posts produced the lowest stresses in the post and post/root interfaces. In Group-II: Roots restored with a T-Post showed a lower concentration stress in the dentin and lower shear stresses in the cement layer compared with those restored with a C-Post.Conclusion: The geometry of the post and the corresponding material play an important role in the stress behavior of restored teeth. The use of titanium or gold-alloy T-Posts seems a good way to improve the stress distribution profile and reduce the risk of restoration failure.  Â

DENTIN POST: A Challenging Post For Commercially Available Posts.

30Apr 2016 DENTIN POST: A Challenging Post For Commercially Available Posts. B.G.Yogesh , M. Srinivas , P.V. Sreedevi , Charithra Shetty , Arun Kumar and Ashwini.

Stress Distribution in Roots Restored with Fiber Posts and An Experimental Dentin Post: 3D-FEA.

The aim of this study was to compare the stress distribution in radicular dentin of a maxillary canine restored with either a glass fiber post, carbon fiber post or an experimental dentin post using finite element analysis (3D-FEA). Three 3D virtual models of a maxillary canine restored with a metal-ceramic crown and glass fiber post (GFP), carbon fiber post (CFP), and experimental dentin post (DP) were obtained based on micro-CT images. A total of 180 N was applied on the lingual surface of the incisal third of each tooth at 45 degrees. The models were supported by the periodontal ligament fixed in three axes (x=y=z=0). The von Mises stress (VMS) of radicular dentin and the intracanal posts was calculated. The structures of all groups showed similar values (MPa) and distribution of maximum von Mises stress. Higher stress was found in the apical third of dentin while the posts presented homogeneous stress distribution along the axis. The fiber and dentin posts exhibited similar stress values and distribution. Thus, the experimental dentin post is a promising restorative material.

Effect of the frequency of mechanical pulses for fatigue aging testing on push-out bond strength between glass fiber posts and root dentin

The aim of this study was to evaluate the influence of the frequency of mechanical pulses during mechanical fatigue aging on bond strength between glass fiber posts and root dentin. Fiber posts were adhesively cemented in 30 bovine roots and the core was built up with composite. All specimens were subjected to mechanical cycling (45° angle; 37 °C; 50 N; 2×106 pulses) at different frequencies: 2, 4, and 8 Hz. After the fatigue, each specimen was submitted to push out test. The bond strength was calculated for data analysis (one-way ANOVA, p = 0.05). The frequency did not affect the push-out (p = 0.7). The main failure mode was between dentin and cement in all groups. The mechanical pulses were not influenced by the bond strength between root dentin and fiber posts. Thus, it is possible to decrease the time-consuming in vitro tests involving posts without damaging the reliability of the test.

Dentin post: A new method for reinforcing the tooth

Ideal coronal reconstruction of a fractured tooth is still a challenge for restorative dentistry. Many post systems are available but none of them have all the ideal biological and mechanical properties. In this case report a dentin post was used for the reinforcement of fractured endodontically treated tooth by virtue of its biomimetic property. Following root canal treatment, a post space was prepared. A direct wax impression was made of the post space. A freshly extracted maxillary cuspid was used to prepare a dentin post, which was then verified in the post space. The dentin post was then luted with dual-cure resin in the canal. Biological dentin posts are considered a good alternative to conventional post systems as they preserve internal dentin walls and provide excellent adhesion and resilience, similar to the natural tooth structure.

Are dentin posts biomechanically intensive?: A laboratory and FEA study

The goal of this laboratory and finite elemental stress analysis (FEA) study was to compare fracture strength of dentin post (DP) with stainless steel and glass fiber posts. Single-rooted teeth were decoronated and restored with ParaPost (PP), i-TFC (TFC), and DPs (n = 10). Resin cores were created and loaded until failure (1.0 mm/min). The data were analyzed (ANOVA, Tukey, Chi-Square tests). Three-dimensional FEA models of the posts were created and the stress distributions were calculated using Solid Works/Cosmos works structural analysis program. A significant difference was found among the groups (p < 0.001). TFC group showed the highest and the DP group showed the lowest fracture resistance (p < 0.001). PP created more stress at the root dentin and inside the post. Restoration of roots with glass fiber and DPs may reduce stresses within the core material and the remaining root. However, a fracture-resistant restoration cannot be achieved by using a DP.

Development of a three-dimensional model for a 135° compression test with biological dental posts

The authors developed a model of a three-dimensional compression test at 135° of a maxillary canine tooth endodontically treated with human and bovine dentin posts and validated it with data from literature. A three-dimensional model of a canine tooth treated endodontically was built with composite resin, cement and periodontal ligament. Simulations of compression tests were performed to validate the force–time curves and then analyze the stress distributions along the tooth. These simulations were designed to show how the use of biological posts can create stresses in places where, if there are fractures, it is possible for the dental surgeon to fix the tooth with a new post, avoiding more radical treatments, such as tooth extraction and dental implant. The simulation was successfully validated with the values of contact force within the standard deviation of that of the mechanical tests. The stresses that occurred along the tooth during the tests were concentrated around the core, crown and root in the cervical region, areas favorable to fracture repair. The work could validate the mechanical tests and make a deeper analysis of the stresses that occur during the experiments. Furthermore, bovine dentin posts show favorable results as a possible material for root retention.

Influence of adhesive system in bond strength of fiber glass posts to radicular dentin using dual cure resin cement

The purpose of this study was to evaluate the bond strength between root dentin and glass fiber posts cemented with dual cure resinous cement associated with the conventional and self-etching adhesive systems. Twenty-four single-rooted human teeth were selected, and the crowns were removed at the cement enamel junction. The roots received biomechanical preparation and obturation followed by the intraradicular preparation compatible with a drill diameter of the glass fiber posts. The roots were divided into two groups, according to cementation protocol (n-12): Group 1 - etched with 37% phosphoric acid for 30 seconds, total-etch adhesive system Single Bond (3M ESPE) and Enforce resinous cement (Dentsply); Group 2 – self-etch adhesive system One Up Bond F (Tokuyama) and Enforce resinous cement (Dentsply). After the posts cementation, the roots were kept at 370 C for one week, and submitted to pull out test on the universal testing machine Emic to a traction speed of 1 mm/min. Data in MPa were submitted to the statistical t-test (5%). The t-test showed significant differences between the two groups (p=0.003). The average values in MPa (±standard-deviation) were: Group 1: 5.28(±3.25), Group 2: 10.05(±3.78). Enforce associated with the self-etch adhesive system One Up Bond F showed significantly higher bond strength values than Group 1 - Enforce associated with the total-etch adhesive system Single Bond.

Comparative Evaluation of Fracture Resistance under Static and Fatigue Loading of Endodontically Treated Teeth Restored with Carbon Fiber Posts, Glass Fiber Posts, and an Experimental Dentin Post System: An In Vitro Study

IntroductionThis investigation sought to compare the fracture resistance under static and fatigue loading of endodontically treated teeth restored with fiber-reinforced composite posts and experimental dentin posts milled from human root dentin by using computer-aided design/computer-aided manufacturing. MethodsSeventy maxillary central incisors were obturated and divided into 4 groups: control group without any post (n = 10), carbon fiber post group (n = 20), glass fiber post group (n = 20), and dentin post group (n = 20). Control group teeth were prepared to a height of 5 mm. In all other teeth, post space was prepared; a post was cemented, and a core build-up was provided. Half the samples from each group were statistically loaded until failure, and the remaining half were subjected to cyclic loading, followed by monostatic load until fracture. ResultsOne-way analysis of variance and Bonferroni multiple comparisons revealed a significant difference among test groups. The control group demonstrated highest fracture resistance (935.03 ± 33.53 N), followed by the dentin post group (793.12 ± 33.69 N), glass fiber post group (603.44 ± 46.67 N), and carbon fiber post group (497.19 ± 19.27 N) under static loading. These values reduced to 786.69 ± 29.64 N, 646.34 ± 26.56 N, 470 ± 36.34 N, and 379.71 ± 13.95 N, respectively, after cyclic loading. ConclusionsResults suggest that human dentin can serve as post material under static and fatigue loading. Although at an early stage in research, the use of dentin posts in root-filled teeth looks promising.