Fiber Post Group Research Articles

Comparative Evaluation of Fracture Resistance in Different Post and Core Systems with Varying Ferrule Locations: An In Vitro Study.

Endodontically treated teeth often require 360° ferrule to retain post and core restoration. The literature support on scientific evidence of partial ferrule is limited, hence this study was conducted to evaluate the fracture resistance of two post and core systems, i.e., Edelweiss and glass fiber post and core system with varying ferrule locations. About 54 extracted mandibular 1st premolars were divided into Edelweiss post and core (Group A) and glass fiber post and core (Group B). They were further subdivided into 3 groups each (Partial functional, partial non-functional, and circumferential). A standardized endodontic procedure was carried out on all the specimens. For group A, an Edelweiss drill of 1.4 mm was used to prepare the post space. Canals were then etched, a bonding agent was applied and posts were luted with paracore resin. For group B, post space was prepared with a straight fissure bur, followed by the same procedure as that of group A. Core build-up was done with composite resin. Cast crowns were fabricated and cemented with GIC. Fracture resistance was evaluated with UTM with a compressive load capacity of 1000 N until fracture occurred. The results of this study stated that in the Edelweiss group partial functional ferrule showed higher fracture resistance and in the glass fiber group circumferential ferrule showed higher fracture resistance. The study also showed that MOF is favorable in all the groups. The type of ferrule was one of the factors that affected the fracture resistance of Edelweiss and Glass fiber post and core group of specimens. The study also concluded that there was a predominant favorable mode of fracture across all groups, in all different ferrule locations. This study opens multiple avenues and methods in tooth restoration and shows that even a partial functional ferrule is sufficient for restoration, provided the right system is used. How to cite this article: Jadhav PD, Shetty R, Mehta D, et al. Comparative Evaluation of Fracture Resistance in Different Post and Core Systems with Varying Ferrule Locations: An In Vitro Study. J Contemp Dent Pract 2024;25(5):480-485.

The influence of zirconia and fiber posts with different lengths on the fracture strength of maxillary central incisors restored with zirconia crowns: an in vitro study.

Endodontically treated teeth are more susceptible to fractures than vital teeth because of significant coronal and radicular dentin loss during endodontic therapeutic procedures. The objective of the present in vitro study was to estimate and compare the influence of the post length and type on the fracture strength of endodontically treated maxillary central incisors. Sixty extracted human maxillary central incisors were decoronated 2 mm above the cementoenamel junction. The teeth were selected and subjected to standard endodontic treatment, resulting in three groups with different preparation lengths: 5, 7.5, and 10 mm. Each group was randomly divided into two subgroups according to the post type: zirconia or fiber. After appropriate surface treatment, they were cemented with adhesive resin cement and restored with zirconia crowns. Thermocycling (5°C to 55°C, 60 s, 1500 cycles) was performed after cementing the zirconia crowns onto each tooth. Prepared samples were subjected to a compressive static load of 0.5 mm/min, at an angle of 130 degrees to the long axis of the roots, using a universal testing machine (Matest) at a crosshead speed of 0.5 mm/min, until fracture. The significance of the results was assessed using two-way analysis of variance (ANOVA) and the Tukey-Kramer test (α = 0.05). The ANOVA analysis indicated significant differences (P < 0.05) between the groups. The Tukey-Kramer test revealed no significant differences among the zirconia posts with lengths of 5 mm (26.5 N ± 13.4), 7.5 mm (25.2 N ± 13.9), and 10 mm (17.1 N ± 5.2). Also, in the fiber post group, there was no significant difference when the posts with lengths of 7.5 mm (13.4 N ± 11.0) were compared with those of 5 mm (6.9 N ± 4.6) and 10 mm (31.7 N ± 13.1). The 10-mm-long post displayed superior fracture strength, and the 5-mm-long post showed significantly lower mean values (P < 0.001). The fracture strength of zirconia posts (with lengths of 5 and 7.5 mm) was found to be significantly higher than that of fiber posts (with lengths of 5 and 7.5 mm). The 10-mm-long fiber post group demonstrated significantly higher fracture strength values, and the 5-mm-long fiber post group showed the lowest values for the force resulting in root fracture; these groups were significantly different from each other (P < 0.001). The fracture strength analysis with a universal testing machine is the only method that enables the estimation of the differences between zirconia and fiber posts with different lengths in endodontically treated teeth.

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

Comparative Evaluation of Fracture Resistance of Carbon Fiber Posts and Glass Fiber Posts in Permanent Anterior Teeth: An In Vitro Study.

Introduction Dental caries and traumatic injuries often lead to tooth loss in adolescents and adults, necessitating endodontic treatment and subsequent restoration. Restoring such teeth presents a challenge due to varying degrees of substance loss. After endodontic treatment, the choice of an appropriate post is crucial for long-term stability. While metal posts are sturdy, they lack aesthetics and may cause root fractures. Fiber posts, such as carbon and glass fiber, offer improved aesthetics and mechanical properties, but their comparative performance warrants investigation. Materials and methods A total of 30 extracted anterior single-rooted teeth were divided into two groups to receive either carbon fiber or glass fiber posts. After endodontic treatment and post-space preparation, the posts were cemented using a dual polymerizing adhesive resin composite. Fracture resistance was assessed using a universal testing machine. Results The mean fracture resistance of the carbon fiber post group was recorded at 271.2 N, whereas the glass fiber post group exhibited a significantly higher mean fracture resistance of 416.133 N. This difference in fracture resistance between the two groups was found to be statistically significant (p < 0.05). Conclusion Glass fiber post systems demonstrated superior fracture resistance compared to carbon fiber post systems in anterior single-rooted teeth. These findings support the clinical preference for glass fiber posts in restoring endodontically treated anterior teeth, offering both mechanical reliability and aesthetic advantages. However, further research, including long-term clinical trials, is warranted to validate these findings and assess the overall clinical performance and longevity of fiber post systems in real-world settings.

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.

Evaluation of microhardness of short fiber-reinforced composites inside the root canal after different light curing methods – An in vitro study

ObjectivesShort fiber-reinforced composite (SFRC) materials make it possible to reinforce root canal treated teeth with individualized, directly layered intraradicular posts (the Bioblock technique). The question arises, however, as to whether the photopolymerization of the material is sufficient deep within the root canal space and if it can be improved through different light-conducting options. Our study aimed to investigate the hardness of intraradicular SFRC material applied using the Bioblock technique and cured with various illumination methods, as measured through nanoindentation. Materials and methodsFor this investigation, thirty plastic artificial teeth that had undergone root canal treatment were selected. These teeth were randomly divided into six study groups (Group 1–6; each group consisting of 5 teeth). The restoration procedures involved the use of SFRC or conventional composite materials, placed 6 mm apically from the root canal orifice. In Group 1 and 2, a conventional composite was used, whereas in Group 3–6, SFRC was employed for interradicular reinforcement (with a layered technique in Group 3 and 4 and a bulk-fill technique in Group 5 and 6). A modified light source was utilized for photopolymerization in Group 2, 4, and 6, whereas in Group 3 and 5, the polymerization light was directed through a prefabricated glass fiber posts. The control group (Group 1) utilized conventional composite material with a standard light-curing method. Following embedding and sectioning, the hardness of the composite materials was measured at 2 mm intervals within the root canal (1st, 2nd, 3rd measurements, in the coronal to apical direction). ResultsDuring the 1st measurement, light curing conducted through the glass fiber posts (Group 3 and 5) led to markedly higher hardness levels compared to the groups restored with conventional composite (control group with p = 0.002, p = 0.001, and Group 2 with p = 0.043, p = 0.034, respectively). In the 2nd measurement, only Group 5 demonstrated significantly greater hardness in comparison to the control group (p = 0.003) and Group 2 (p = 0.015). However, in the 3rd measurement, no statistically significant differences were observed among the groups. Conclusionlight curing through the glass fiber post provides outstanding hardness for the SFRC material in the apical layer in the root canal.

Effects of glass fibers reinforced and non-reinforced composite resin on fracture behavior of severely destructed primary incisors and restored with post and core system

ObjectiveTo evaluate fracture resistance and failure type of coronally rehabilitated primary incisors with EverX Flow or Grandio Core post and core with or without fiber post. Materials and MethodsForty-eight extracted maxillary primary incisors were root canal treated and obturated with Metapex. The coronal 4-mm of Metapex was removed to create 3-mm intracanal post space. Next, coronal enamel and radicular dentin surfaces were acid-etched, and a bonding agent was applied and light-cured. Based on intracanal post and 2-mm height core buildup materials, specimens were divided equally (n = 12) into 4 groups as follow; Group I (EverX Flow), Group II (Grandio Core), Group III (Fiber post, and EverX Flow), and Group IV(Fiber post and Grandio Core). The coronal restorations were finalized to 4-mm height using G-aenial Anterior composite and specimens were tested for fracture resistance. Force required to induce fracture was recorded and failure type was examined. ResultsFracture resistance of Fiber post and EverX Flow group was statistically significant high than other tested groups. However, fracture resistance of EverX Flow group showed non-statistically significant difference from that of Fiber post and Grandio Core group. Regarding failure type, no specimen presented root fracture, and all failures were favorable and repairable. ConclusionEverX flow post and core with or without fiber post enhanced fracture resistance of restored primary incisors compared to Grandio Core alone. Clinical relevanceEverX flow post and core system with or without fiber post could be a promising restorative option for severely destructed primary incisors.

In Vitro Comparison of Fracture Resistance of Severely Damaged Primary Anterior Teeth Restored with Different Post and Core Systems.

This study aimed to compare the fracture resistance (FR) of severely damaged primary anterior teeth restored with five different post and core systems. This in vitro, experimental study evaluated 60 extracted primary maxillary central incisors. The teeth were horizontally sectioned at 1 mm above their cementoenamel junction (CEJ), underwent pulpectomy, and their root canals were filled with Metapex paste. After post space preparation and sealing of root fillings with light-cure glass ionomer (1 mm thickness), the teeth were randomly assigned to five groups (n = 12) of (1) glass fiber post and everX composite (reinforced with short fibers), (2) glass fiber post and bulk-fill composite, (3) everX composite post and core, (4) bulk-fill composite post and core, and (5) Filtek conventional composite post and core. The teeth underwent 5,000 thermal cycles between 5°C and 55°C, and their FR was measured in a universal testing machine (0.5 mm/min, 148°). The mode of failure was also determined. Data were analyzed by ANOVA and Tukey's test at 0.05 level of significance. The FR was the highest in fiber post and everX composite, and the lowest in Z250 conventional composite post and core group (P < 0.001). The FR of fiber post and everX composite group was significantly higher than that of everX composite post and core (P = 0.04), bulk-fill composite post and core (P = 0.001), and Z250 composite post and core (P < 0.001) groups. The frequency of repairable fractures was the highest in glass fiber post plus everX composite (91.66%) and the lowest in Filtek conventional post and core group (66.66%) (P > 0.05). Within the limitations of this in vitro study, the results showed that restoration of severely damaged primary maxillary central incisors with glass fiber post and everX composite reinforced with short fibers enhanced their FR, and increased the chance of reparability in case of restoration fracture. This technique may be recommended for the restoration of primary anterior teeth since it is simple and saves time.

A Comparative Study of Fracture Resistance of Endodontically Treated Compromised Teeth with Different Post Systems: An In Vitro Study

Aims: This in-vitro study was conducted to compare structural reinforcement with composite resin and two different types of posts in structurally compromised teeth. Methods and Materials: Forty-eight human maxillary central incisors were instrumented and obturated. Specimens were randomly divided into four groups. The control group was not compromised and was just restored with a resin composite. In the composite-reinforced group, the access cavity of the compromised teeth was restored only with composite to the cemento-enamel junction (CEJ). In the reinforced glass fiber post group, the compromised cervical area of the teeth was reinforced with a dual-cured composite and a glass fiber post. The reinforced metal cast post group was reinforced with a dual-cured composite and a casting post. The mean fracture load was measured. Data were analyzed by SPSS software using one-way analysis of variance (ANOVA) and chi-square statistical analysis tests. For pair comparison, Duncan was used. P&lt;0.05 was considered statistically significant. Results: The highest fracture resistance values were for the non-compromised samples (170.12 ± 12.44), while the lowest values were for the compromised ones restored only with the resin composite (71.40 ± 17.00). There was no statistically significant difference between the mean fracture resistances of the fiber (129.36 ± 21.34) and cast (116.60 ± 22.60) post groups (P&gt;0.05). Conclusion: The use of a composite resin in a root with thin walls will reinforce the compromised tooth, but the type of the post will not influence the final results.

Fracture resistance of endodontically treated maxillary premolars with Mesio-occluso-distal (MOD) cavities supported by horizontal glass fiber posts versus vertical glass fiber posts: An in vitro study

Aim: The aim of this study was to assess the fracture resistance of endodontically treated maxillary premolars with mesioocclusodistal (MOD) cavities supported by horizontal glass fiber posts. Methodology: Thirty three extracted maxillary premolars were collected and grouped into three. MOD cavities were prepared and all of them were endodontically treated. Teeth were supported with horizontal glass fiber posts; vertical glass fiber posts and composite restoration alone in the three groups respectively. Fracture resistance assessed using Universal testing machine. Type of fracture was assessed using visual examination. Type of failure was assessed using Stereomicroscope. Results: Highest fracture resistance was shown by samples supported by horizontal fiber post (Group C). Group B had higher chances of Type 1 failure (Adhesive failure between post and luting cement) compared to other groups. Group A had higher chances of Type 4 failure (Cohesive failure) and Group C had higher chances of Type 5 failures (Mixed type; combination of any two of the above-mentioned types).There was no statistically significant association between groups and fracture mode (repairable and unrepairable). Majority of samples from Group A and Group C underwent repairable fractures. Conclusion: Fracture resistance of horizontal fiber post group was significantly higher compared to the other two groups.

An in vitro study to evaluate the fracture resistance of different types of posts

Abstract Aim: The aim of this study was to evaluate the fracture resistance of endodontically treated maxillary central incisors restored with carbon fiber and glass fiber posts under static loading and evaluate their modes of failure. Materials and Methods: Sixty freshly extracted human maxillary central incisors were collected and root canal treatment was performed in all. Forty out of 60 teeth were sectioned 4 mm away from the cemento–enamel junction coronally and posts were placed in them. Rest 20 teeth were left intact to be used as controls. The groups were divided as follows: I—control group, II—carbon fiber group, and III— glass fiber group, All specimens were then mounted on an acrylic test block and subjected to static loading until fracture and the mode of fracture were recorded. Statistical analysis was carried out using analysis of variance (ANOVA) to calculate the mean values of all groups. An intergroup comparison was carried out using Tukey’s post hoc test. Results: The study showed that group I showed the highest fracture resistance followed by group III, which was the glass fiber post group under static loading. There was a significant difference among the test groups. The main cause of fracture was debonding of the core in all the fiber posts. Conclusion: Teeth of the control group showed the highest fracture resistance and teeth restored with glass fiber posts showed higher fracture resistance than those restored with carbon fiber posts under static loading (P &lt; 0.05). The principal mode of fracture was debonding of the core and remaining root. Teeth restored without application of a post showed the highest fracture resistance than all other groups.

Farklı Fiber Post Sistemleri ve Rezin Simanların Bağlanma Dayanımı: Deneysel Çalışma

Objective: The aim of this study was to compare the push-out bond strength (BS) of 2 different conventional fiber and glass fiber posts in the form of bundles by using 2 different resin cement and the fracture types formed accordingly. Material and Methods: Root canal treatment was applied to 48 extracted human premolars for the push-out test. The teeth were divided into 3 fiber post groups: Group 1: Biolight ST (conventional fiberpost), Group 2: RelyX (conventional fiberpost), Group 3: Biolight Plus (bundle post) according to the posts to be used for the push-out test. Each of the fiber post groups were divided into 2 subgroups according to adhesive cement [Core-X Flow, Build It FR] used in the cementation of posts (n=8). One mm sections were taken from the middle third of posts and the sections were subjected to a push-out test and the values were recorded. The samples were examined under a stereomicroscope and fracture types were determined. Results: No statistically significant difference was found between the groups according to the test results. When the fracture types were evaluated for all groups, there was no statistically significant difference in the result. Conclusion: The fiber post system in the form of bundles has similar properties with the conventional glass fiber post system in terms of BS.

Biomechanical behavior of weakened roots restored with custom-made post-and-cores of glass fiber and polyetheretherketone.

To evaluate the influence of post type and mechanical aging on compression force resistance, fracture pattern, and stress distribution in weakened roots. Bovine roots were endodontically treated and widened-and randomly divided into 8 groups (n = 10) according to post type (prefabricated glass fiber post and customized anatomic glass fiber post, milled glass fiber post-and-core, and milled polyetheretherketone post-and-core) and mechanical aging (without and with mechanical aging). Three hundred thousand cycles of mechanical fatigue were performed and compression force resistance (N) was analyzed by two-way ANOVA and Tukey test (α = 0.05). Fracture patterns were reported and stress distribution was analyzed by finite elements analysis. There was a significant effect of post type (p = 0.032) and mechanical aging (p = 0.009), but no double interaction (p = 0.879). Higher values were recorded in the milled glass fiber and polyetheretherketone post-and-core groups compared to the prefabricated glass fiber post groups, and no significant difference was found among anatomic glass fiber post groups and other groups. Reparable fractures were predominant in the milled glass fiber and polyetheretherketone post-and-core groups. Prefabricated glass fiber posts and milled polyetheretherketone post-and-cores showed similar stress distribution. Post type and mechanical aging influence the compression force resistance and fracture pattern of weakened roots. Milled glass fiber and polyetheretherketone post-and-cores exhibited higher compression force resistance and more reparable fractures compared to prefabricated glass fiber posts. Prefabricated glass fiber posts and milled polyetheretherketone post-and-cores showed similar stress distribution.

Effect of Different Post Materials and Adaptability on Fracture Resistance and Fracture Mode in Human Endodontically Treated Teeth.

Objective To investigate the effect of different post materials and adaptability on fracture resistance and fracture mode of endodontically treated teeth. Materials and Methods Sixty extracted human mandibular premolars were selected and divided into 6 groups (n = 10) according to the restorative method after endodontic treatment: no ferrule presented and restored without fiber post (Group C), 2.0 mm ferrule presented and restored without fiber post (Group CF), restored with D.T. Light-Post (Group PDT), restored with anatomically customized D.T. Light-Post, relined with resin composite (Group ADT), restored with Hi-Rem prosthetic post (Group PHR), and restored with anatomically customized Hi-Rem prosthetic post, relined with resin composite (Group AHR). After restoring with core build-up materials, all specimens were loaded at 45° in a universal testing machine until failure. Visual inspection of all specimens for fracture modes was performed. The data were analyzed using one-way ANOVA, and the fracture mode was reviewed using the chi-square test. Results Anatomically customized groups presented statistically significant higher fracture resistance than prefabricated groups and group C (P < 0.05). Without post, group CF displayed significantly higher fracture resistance than group C (P < 0.05). Group C, CF, PDT, and PHR showed some specimens with unfavorable fractures. Conclusions Anatomically customized posts presented highest fracture resistance among all groups. There was no significant difference in fracture mode across all groups.

Fracture Resistance and Stress Distribution Pattern of Different Posts-Core Systems in Immature Teeth: An In Vitro Study and 3D Finite Element Analysis.

Introduction Restoration of immature teeth with open apices and thin dentinal walls with conventional post systems remains a challenge. The purpose of this study was to evaluate the fracture resistance of simulated immature teeth restored with different intraradicular posts and assess their stress distribution pattern using 3D Finite Element Analysis (FEA). Methods Fracture strength testing using universal testing machine was carried out in simulated immature teeth restored with different intraradicular posts grouped as follows: Group A: teeth not restored with posts served as control group; Group B: Cast metal post (CMP); Group C: Customized Composite Post (CCP); Group D: Fiber post (FP). Four 3D FEA models of the above groups were created using CATIATM software and analyzed for stress distribution using ANSYSTM. The results of fracture strength testing and FEA were correlated. Multiple group comparisons were analyzed by one-way ANOVA followed by Tukey HSD post hoc test. Results The CMP exhibited highest fracture resistance (336.43 N) but resulted in root fractures. The CCP exhibited lower fracture resistance (240.90 N) and favorable stress distribution as compared to CMP. The FP and control group exhibited lower fracture resistance values of 182.69 N and 130.46 N, respectively. The results of 3D FEA demonstrated higher stress concentration in model comprising metallic post and core. Conclusions Teeth restored with cast metal posts and cores exhibited maximum fracture resistance followed by the customized composite posts, the fiber posts, and the control group. The cast metal posts indicated higher von Mises stresses concentrated in the radicular region; however, the customized composite posts, the fiber posts, and the control group demonstrated stress concentration in the coronal region.

Comparative evaluation of the force required to fracture coronal segments reattached using different methods.

Anterior teeth are prone to traumatic injuries. Their management is necessary in order to maintain the pulp and esthetics. Various methods have been reported for fragment reattachment of fractured teeth but there is no consensus on which is the best technique. The aim of this study was to compare the force required to fracture reattached fragments using polyethylene fibers in vertical grooves on the external surface of teeth, fiber-reinforced composite post and circumferential chamfer. Forty-eight extracted maxillary central incisors were sectioned using a disk and randomly divided into 4groups (n=12): Group 1: control group, Group 2: reattachment followed by placement of two external vertical grooves on the labial surface and restored with polyethylene fibers and hybrid composite, Group 3: reattachment followed by two external vertical grooves and filled with fiber posts and composite, and Group 4: reattachment followed by circumferential chamfer at the fracture line and restored with composite. The forces required to fracture the reattached fragments were measured using a Universal testing machine. Data were analyzed using the Kruskal-Wallis test. Pairwise multiple comparison procedure was done using the Student-Newman-Keuls Method. The highest values for force required to fracture were observed in the fiber post group and the lowest in the Ribbond group (p<.05). The fiber post group had significantly different results compared to the Ribbond and Chamfer preparation groups (p<.05). However, the difference of rank between the fiber post and control groups was not significantly different (p>.05). The force required to fracture the fiber post group was closest to that of intact teeth followed by the chamfer and Ribbond groups, respectively.

Interface analysis after fatigue loading of adhesively luted bundled fiber posts to human root canal dentin

ObjectivesThe aim of this study was to assess the fatigue loading behavior and fracture resistance of endodontically treated teeth restored with adhesively luted bundled fiber posts in comparison to solid fiber posts. Image analysis (2D and 3D) was applied to evaluate modes of failure and to characterize susceptible parts of the post-and-core interface. MethodCrowns of 72 human similar-sized central upper incisors were removed and roots received a conventional root canal filling prior to establishing 4 groups of core build-up: No Post group (nP) received a 4 mm deep filling made of composite inside the canal with no dental post, fiber post group (FP) received a conventional solid post, and two experimental groups received bundles of 6 (FB6) or 12 (FB12) 0.3 mm thin fiber posts, respectively. Posts were placed adhesively inside the root canal using a dual-curing build-up composite in combination with a self-etch adhesive, the latter was also used for nP group. Upon completion of core build-ups, all teeth received full-ceramic crowns that recreated the original tooth form. Samples were subjected in a 135° angle to thermo-mechanical loading (TML) for 1.2 Mill. chewing cycles followed by static load tests (fracture resistance). Fracture modes as well as intracanal failure modes with respect to failed interfaces were analyzed using optical and electron microscopy (SEM). Microcomputer tomography (μCT) was used to exemplary compare pre and post TML geometries. ResultsStatic load test was significantly different between groups (p < 0.0005; Kruskal-Wallistest). Pairwise comparison showed that the nP group (221 ± 103N) failed at significantly lower forces compared to the FP (454 ± 184N), FB6 (477 ± 250N) and FB12 (478 ± 260N) groups (p ≤ 0,001; Mann-Whitney-U-test). Fracture modes were significantly affected by the presence or absence of a post (p ≤ 0,016; Chi-square test) revealing increased incidence of restorable fractures at the cervical region for nP group. Microscopic analysis revealed more intracanal failures at interfaces between post surfaces and composite for solid posts, whereas fiber bundled posts mostly failed at the interfaces between composite and dentin. Micro-CT analysis showed no alterations of the root-post-and-core structure after TML except slight deformations of occasionally entrapped voids. ConclusionFracture resistance and fracture modes were significantly affected by the presence or absence of a post, whereas the investigated post groups did not differ from each other. However intracanal failure revealed differences in adhesive failures between solid fiber posts and bundled fiber posts. Deformations of entrapped voids, revealed by micro-Ct analyses after TML, lead to the assumption that applied forces result in alterations in the regions of voids.

Resin Composite Core and Fiber Post Improved the Fracture Parameters of Endodontically Treated Maxillary Premolars with Wedge-shaped Cervical Lesions

IntroductionThe aim of this study was to evaluate the fracture resistance and fracture patterns of endodontically treated maxillary premolars with wedge-shaped cervical lesions restored with a resin composite core with or without a fiber post under nonaxial loading. MethodsSixty extracted human maxillary premolars with 2 root canals were randomly allocated into 4 groups (n = 15). Forty-five teeth were prepared with a wedge-shaped lesion at the buccal cervical area and root canal treatment. There were 3 restoration groups: no restoration, restoration with a resin composite core, and restoration with a resin composite core and a fiber post. Intact teeth served as the control group. All teeth were subjected to thermocycling and cyclic loading. A 45° compressive load was applied to the palatal plane of the buccal cusp until tooth fracture. The fracture resistance and facture patterns were analyzed using 1-way analysis of variance and the chi-square test (α = 0.05), respectively. ResultsThe no restoration group demonstrated the lowest fracture resistance and was significantly different from the other groups (P < .001). The intact teeth presented the highest fracture resistance, which was not significantly different from the restoration with a resin composite core and a fiber post group (P > .05). The failure patterns were significantly different between groups (P < .001). Most intact teeth fractured coronally to the cementoenamel junction level, whereas most teeth in the other groups fractured at the gingival margin of the cervical lesion. ConclusionsEndodontically treated maxillary premolars with wedge-shaped cervical lesions restored with fiber posts and a resin composite cores had a fracture resistance equivalent to intact teeth. However, their fracture patterns were not improved by the fiber post and a resin composite core.

Evaluation of composite resin core with prefabricated polyetheretherketone post on fracture resistance in the case of flared root canals.

The aim of this study was to use polyetheretherketone (PEEK) for the post material and evaluate the fracture load of six restoration patterns in teeth with flared root canals; composite resin core alone (Group R); glass fiber sleeve (Group S); PEEK post (Group P); glass fiber post (Group F); PEEK post in glass fiber sleeve (Group PS); glass fiber post in glass fiber sleeve (Group FS). In this study, cylindroid specimens were prepared and underwent three-point-bending test in a steady condition and after water immersion. In the loading test, the materials in clinical conditions using bovine teeth were evaluated. In the bending test, groups using glass fiber posts and sleeves decreased in strength after water immersion. In the loading test, Groups F, FS and PS showed higher fracture load than other groups. This study showed PEEK posts and glass fiber sleeves are recommended in the case of flared root canals.

Randomized controlled trial comparing glass fiber posts and cast metal posts

ObjectiveThis study aimed to assess the survival and success of glass fiber posts compared to cast metal posts in teeth without ferrule. Material and MethodsAn equivalency, prospective, double-blind (patient and outcome evaluator) randomized controlled trial (RCT) with parallel groups was designed to compare the clinical performance of cast metal and glass fiber posts cemented in endodontically treated teeth without ferrule (NCT01461239). Teeth were randomly allocated to the glass fiber or cast-metal post groups. All teeth were restored with single metal-ceramic crowns. Kaplan-Meier analysis with the log-rank test was used to test the success and survival between glass fiber and cast metal posts considering a cut-off value of P = 0.05. The annual failure rates were calculated considering the survival data for all restorations and separated by type of post after five years. ResultsA hundred and nineteen patients and 183 posts (72 cast metal posts and 111 glass fiber posts) were analyzed. The median follow-up was 62 months (IQR 37–81). The log-rank test for success (P = 0.26) and survival (P = 0.63) analyses did not present statistically significant differences. The AFR of both posts after 5 years was 1.5%. Considering the posts separately and after 5 years, cast metal posts presented AFR of 1.2% and glass fiber posts AFR of 1.7%. Most failures were in posterior teeth (16/23), 10 failures were classified as root fractures and 5 as post debonding. The follow-up rate was 95.3%. ConclusionsGlass fiber and cast metal posts showed good and similar clinical performance. Clinical SignificanceResults of this randomized controlled trial can help dentists to answer how the best technique to rehabilitate endodontically treated teeth with no remaining coronal wall.