Microtensile bond strength of root canal dentin treated with adhesive and fiber-reinforced post systems

Effects of a relined fiberglass post with conventional and self-adhesive resin cement

Objectives

This study was conducted to evaluate the mechanical properties of relined and non-relined fiberglass posts when cemented to root canal dentin using a conventional dual-cure resin cement or a self-adhesive resin cement.

Materials and Methods

Two types of resin cements were utilized: conventional and self-adhesive. Additionally, 2 cementation protocols were employed, involving relined and non-relined fiberglass posts. In total, 72 bovine incisors were cemented and subjected to push-out bond strength testing (n = 10) followed by failure mode analysis. The cross-sectional microhardness (n = 5) was assessed along the root canal, and interface analyses (n = 3) were conducted using scanning electron microscopy (SEM). Data from the push-out bond strength and cross-sectional microhardness tests were analyzed via 3-way analysis of variance and the Bonferroni post-hoc test (α = 0.05).

Results

For non-relined fiberglass posts, conventional resin cement exhibited higher push-out bond strength than self-adhesive cement. Relined fiberglass posts yielded comparable results between the resin cements. Type II failure was the most common failure mode for both resin cements, regardless of cementation protocol. The use of relined fiberglass posts improved the cross-sectional microhardness values for both cements. SEM images revealed voids and bubbles in the incisors with non-relined fiberglass posts.

Conclusions

Mechanical properties were impacted by the cementation protocol. Relined fiberglass posts presented the highest push-out bond strength and cross-sectional microhardness values, regardless of the resin cement used (conventional dual-cure or self-adhesive). Conversely, for non-relined fiberglass posts, the conventional dual-cure resin cement yielded superior results to the self-adhesive resin cement.

Current Insights on Fiber Posts: A Narrative Review of Laboratory and Clinical Studies

PURPOSE

The aim of this study was to review the literature related to the clinical performance and laboratory findings regarding fiber posts, as well as the cementation technique employed with their use.

MATERIALS AND METHODS

A literature search was performed using an electronic database, PubMed/Medline, between 2010 and 2023. The terms used were "intra coronal post, fiber post, post cementation, and post length". Titles and abstracts were initially screened, and a full-text assessment was conducted for those that fulfilled the inclusion criteria. The reference list of the collected papers was also screened for further relevant citations.

RESULTS

In this work, 135 potentially eligible studies were analyzed. Titles and abstracts of 90 studies followed the inclusion criteria and were selected for a full-text assessment, resulting in 50 studies selected. Moreover, additional studies from relevant citations were included, totaling 57 studies.

CONCLUSION

According to the laboratory and clinical studies revised, the survival rate between fiber and prefabricated and cast metal posts was similar, and failures were mainly related to the loss of retention. The intra-canal post length of less than two-thirds of the root length presented successful results when ferrule was present. Furthermore, the ferrule increased the longevity of teeth restored with fiber posts. Additionally, the use of a surface treatment protocol for fiber posts and the adhesive cementation technique both contributed to the clinical success and longevity of the intra-canal post.

Evaluation of Poly(etheretherketone) Post's Mechanical Strength in Comparison with Three Metal-Free Biomaterials: An In Vitro Study

The thinking about metallic replacement has begun in a global context of reducing metallic alloys' use in odontology. Among the materials proposed for their replacement, poly(etheretherketone) may present interesting properties, especially in removable dentures' frames. The purpose of this study is to evaluate fracture resistance of PEEK posts-and-cores compared to non-metallic CAD/CAM materials and fiber glass posts. Forty extracted maxillary central incisors were prepared to receive posts. Samples were divided into four groups depending on whether they had been reconstructed with LuxaCam® PEEK, Enamic®, Numerys GF® or LuxaPost®. Samples were submitted to an oblique compressive test and results were statistically analyzed with ANOVA and Student's tests (or non-parametric tests depending on the conditions). Glass fiber posts and Numerys GF® reveal a significantly higher fracture resistance than LuxaCam® PEEK and Enamic®. No exclusively dental fracture has been noted for the Enamic group, which significantly distinguishes these samples from the three other groups. In our study, it appears that the conception of posts and cores with hybrid ceramic never conducts to a unique tooth fracture. By weighting the results according to the materials used, our data, obtained for the first time on this type of PEEK block, cannot confirm the possibility of using PEEK for inlay-core conception, excepted for specific cases when the material is considered in a patient presenting allergies or systemic disease contraindicating resin or metal.

Assessment of the Push-Out Bond Strength for Glass Fiber Posts After Different Surface Treatments: An In Vitro Study

AIM

The goal of the study was to assess the push-out bond strength of the glass fibre post after different surface treatments.

MATERIALS AND METHODS

For the purpose of the investigation, 40 mandibular premolars were chosen. After gaining access, the biomechanical preparation was completed using the step-back approach up to a size 40K file, and the canals were sealed using gutta-percha cones and the lateral condensation procedure with AH Plus sealer (epoxide-amine resin pulp canal sealer). Peeso reamers were used to remove the canal fillings, leaving 5mm of gutta-percha apically. Drills included in the package were used to prepare the post spaces so that the posts would fit in their respective post slots. These were attached to self-curing acrylic resin blocks. Fibre posts were split into four groupings of n = 10 each for surface treatment, i.e., control, hydrogen fluoride, sandblasting, and hydrogen peroxide. The cementation of posts was done by utilising dual-cure resin cement. Two millimetres of the anatomical crown were removed from each sample. Each sample's 1-mm cervical segment was taken utilising the isotope from the remaining coronal area. To perform a push-out test, at the rate of 0.5mm/min of the crosshead, every sample was inserted into a universal testing device. Each post's dislodge force from the pre-set post spacing was measured. Statistics were utilised to analyse the data.

RESULTS

Strongest bonds were made by silanization, followed by sandblasting (p value=0.002). The weakest bonds were made by the control group.

CONCLUSION

The ultimate deduction was that when glass fibre posts underwent various types of surface treatments followed by silanization, it had a significant impact on increasing their strength.

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

OBJECTIVES

To evaluate the bond strength of four types of posts (pre-fabricated fiberglass post, fiberglass post anatomized with composite resin, milled fiberglass post, and milled polyetheretherketone (PEEK) post), and two types of resin cements (conventional and self-adhesive) by assessing immediate bond strength and post-mechanical aging at each root third.

MATERIALS AND METHODS

Bovine endodontically treated roots (16 groups, n = 8) were prepared and the posts were produced and luted; the specimens of aging groups were cycled (300,000 cycles under 50 N load at 1.2 Hz frequency); six slices of each root were obtained; push-out test was performed by using a universal testing machine (500 N load at 1 mm/min cross speed); fracture pattern was classified into five levels. The statistical analyses used were three-way ANOVA, Tukey's test (for bond strength), and Fisher's test (for fracture pattern) (α < 0.05).

RESULTS

Differences were found between the cements for posts (conventional: p < 0.001; self-adhesive: p = 0.002), whereas no difference was found for root region (p = 0.941; p = 0.056, respectively); analysis of each root showed significant differences for cements (p < 0.001), posts (p < 0.001), and mechanical cycling (p = 0.001); in terms of double interaction, differences were found for posts and mechanical cycling (p = 0.005); no other interactions were observed (double or triple); the fracture pattern showed difference between the groups for both cements.

CONCLUSIONS

Milled PEEK posts seem to be a good clinical option, but they require improvement of CAD-CAM technology and advances towards their adhesion.

CLINICAL RELEVANCE

Milled posts are promising and can reduce clinical time for rehabilitation of extensively destroyed teeth.

The Effect of Different Fiber Post-Application Techniques on Fracture Resistance of Structurally Compromised Premolars with Flared Root Canals: An In Vitro Study

Aim:

Intraradicular post systems have become an important treatment method for endodontically treated teeth as they provide retention for restoration to the remaining tooth structure. The objective of the present in vitro study was to evaluate the effect of different fiber post-application techniques on the fracture resistance of premolars with flared root canals and no ferrule.

Materials and Methods:

Sixty freshly extracted, single-rooted mandibular premolars with no ferrule were endodontically treated by an experienced endodontist, and their root canals were experimentally flared. The specimens with flared root canals were divided into five groups according to fiber post-application techniques ( n = 12): a prefabricated fiber post (G1), G1 + two auxiliary posts (G2), i-TFC post system (G3), G1 + quartz splint (G4), and Ribbond (G5). The data were analyzed with analysis of variance and Tukey tests.

Results:

The findings were revealed that no significant difference was found among four groups, except G5 ( P > .05), which demonstrated the lowest fracture resistance ( P < .05). G2, G3, G4, and G5 exhibited dominantly restorable fracture pattern, whereas G1 exhibited nonrestorable fracture pattern.

Conclusion:

Within the limitations of this study, the placement of auxiliary posts, i-TFC post system, quartz splint placement, and Ribbond increased the incidence of restorable fracture compared with the controls.

Effect of Glass Fiber Post Surface Treatment on Bond Strength of a Self-Adhesive Resin Cement: An "In Vitro" Study

Objective

This study evaluated the influence of different mechanical and chemical surface treatments alone and combined with silane on the bond strength (BS) of glass fiber posts (GFPs) using self-adhesive resin cement.

Methods

Eighty-four single-rooted bovine teeth (six groups, n = 14) were submitted to BS analysis after GFP cementation. The treatments applied in the studied groups were no surface treatment (control), silane (S), 24% hydrogen peroxide (PER), 24% hydrogen peroxide and silane (PER + SIL), blasting with 50 μm aluminum oxide particles (BLAST), and blasting with 50 μm aluminum oxide particles and silane (BLAST + SIL).

Results

BS differed significantly among groups (p < 0.001). It was higher in the SIL (10.5 ± 3.5 MPa), BLAST + SIL (11.5 ± 3.2 MPa), and PER + SIL (11.6 ± 4.6 MPa) groups than in the control (6.5 ± 2.9 MPa), BLAST (8.6 ± 4.0 MPa), and PER (7.1 ± 2.8 MPa) groups, with no significant difference among groups receiving silanization. Cement post adhesive failure was more common in the SIL, BLAST, and PER + SIL groups, and cement-dentin adhesive failure was more common in the control, BLAST + SIL, and PER groups.

Conclusion

These results show that silane application alone increases BS.

Is a fiber post better than a metal post for the restoration of endodontically treated teeth? A systematic review and meta-analysis

OBJECTIVE

To evaluate systematically the evidence about the failure rates of endodontically treated teeth (ETT) restored with intraradicular metal posts (MPs) or fiber posts (FPs).

DATA

The review protocol was registered on PROSPERO (CRD42020189792). Eligibility criteria included randomized clinical trials (RCT) and prospective clinical trials (PCT) that compared the failures between FP and MP restorations for ETT. Meta-analyses were conducted for failure rates using fixed- and random-effects models. Subgroup and funnel plot analyses were performed.

SOURCES

Four electronic databases (MEDLINE/PubMed, Web of Science, Scopus, and Cochrane Library), manual, and grey literature were screened by two researchers independently for articles published until November 2020 without language or time restrictions. For the analysis of the risk of bias, the Cochrane collaboration tool and ROBINS-I were used. The certainty of the evidence was evaluated using GRADE.

STUDY SELECTION

Ten studies were included. A total of 704 participants with a mean age of 42.7 years with a total of 844 ETT were restored using 453 FPs and 391 MPs. The FPs presented similar failures to that with MPs (P=0.39; risk ratio [RR]:0.82; 95% confidence interval [CI]: 0.52 to 1.29). Subgroup analysis showed no significant differences between the FPs and MPs for the anterior region (P=0.60; RR:0.88; [CI]: 0.54 to 1.42), posterior region (P=0.52; RR:1.18; [CI]: 0.71 to 1.98), root fracture (P=0.44; RR:0.78; [CI]: 0.41 to 1.49), and debonding (P=0.56; RR:1.27; [CI]: 0.57 to 2.80). Additionally, FP showed similar failures compared with those of cast (P=0.36; RR:0.63; [CI]: 0.23 to 1.72) and prefabricated MPs (P=0.68; RR:0.90; [CI]: 0.54 to 1.50). The RCT and PCT studies revealed a low risk of bias for most of the domains. However, the certainty of evidence was considered low.

CONCLUSION

No evidence of difference was observed for failure rates between FPs, and MPs, independent of region and different MPs used in ETT. However, further well-conducted clinical studies with high-quality evidence are encouraged.

CLINICAL SIGNIFICANCE

Our results indicate that both retainer posts can be considered an adequate alternative in restoring ETT. Therefore, the choice of post (fiber or metal) could be based on dentist preference or individual characteristics of the patient as the failure rates for different posts are similar.

Effect of post-space irrigation with acid solutions on bond strength and dentin penetrability using a self-adhesive cementation system

Background

The aim of this study was to evaluate the effects of surface treatments with 1% peracetic acid (PA), solution containing 17% EDTA (SmearClear, Kerr Endodontics), solution containing a combination of 17% EDTA with 2% chlorhexidine (QMix, Dentsply Sirona) on the post-space root dentin compared to 2.5% sodium hypochlorite (NaOCl) on bond strength and resin tags length in dentin.

Material and Methods

Forty human-canine roots were endodontically treated and the post space was prepared. The specimens were randomised into four groups (n = 10): control – irrigation with 2.5% NaOCl solution, PA – irrigation with 1% PA, SmearClear – irrigation with SmearClear solution, and QMix – irrigation with QMix solution. The fibre posts were cemented using a self-adhesive resin system (Relyx U200, 3M ESPE). After six months, the specimens were cross-sectioned and subjected to push-out and confocal laser microscopy tests. One-way ANOVA and Tukey’s tests were used to analyse the data (α= 0.05).

Results

PA and QMix presented the highest bond strength values compared to the other groups (p< 0.05). There was no significant difference between the resin tags length in dentin by the groups (p = 0.75).

Conclusions

Irrigation of the post space with 1% PA and QMix showed a positive clinical impact on the adhesion between the fiber post and root dentin. However, these materials had no influence on resin tags length in dentin by self-adhesive resin cement.

Key words:Fiber post, adhesive cementation, self-adhesive resin cement, root dentin, irrigating solutions.

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

Purpose:

The aim of this study was to evaluate the adhesive bond strength of fiberglass posts treated with experimental silanes based on thio-urethane and submitted to thermo and mechanical cycles.

Materials and methods:

Bovine roots were divided into six groups: RX-RU2 (RelyX CP + RelyX U200); PETMP-HDDI-RU2 (PETMP-HDDI + RelyX U200); PETMP-BDI-RU2 (PETMP-BDI + RelyX U200); RX-RU (RelyX CP + RelyX Ultimate); PETMP-HDDI-RU (PETMP-HDDI + RelyX Ultimate); PETMP-BDI-RU (PETMP-BDI + RelyX Ultimate). One slice from each root third (n=10) was submitted to the push-out test and the values evaluated with R Program statistical analysis, while the failure pattern assessed in percentage.

Results:

Among root thirds, RX-RU2 promoted greater strength at the cervical and apical thirds; PETMP-HDDI-RU2 showed highest values at the three thirds; and PETMP-BDI-RU2 was strongest at the apical third. RX-RU presented higher strength at the apical third, and PETMP-HDDI-RU and PETMP-BDI-RU had similar values at the three thirds. In each root third, PETMP-HDDI-RU2 showed similar strength at all thirds, and similar strength at the apical third was observed for other associations. Mixed and adhesive failures predominated.

Conclusion:

Experimental silanes promoted different bond strength values in the adhesion of fiberglass posts to the root thirds, with better results for PETMP-HDDI silane. The root region did not influence the failure pattern and most slices showed mixed (MCDP) or adhesive (ADP) failure.