Impact of different surface treatment methods on bond strength between fiber post and composite core material

The effect of touch-cure polymerization on the push-out bond strength of fiber posts

Objective

To assess the impact of a novel touch-cure polymerization of dual-curing resin cement on the push-out bonding strength (PBS) of the conventional prefabricated glass fiber-reinforced composite (GFRC) and custom-made glass fiber (GF) posts at different root sections.

Methods

Forty single-root mandibular first premolars were treated endodontically and prepared for receiving the posts, the prepared roots were randomly divided into 4 groups. Group I: A prefabricated (GFRC) post was cemented by G-CEM ONE resin cement with adhesive-enhancing primer (AEP). Group II: A prefabricated (GFRC) post was cemented by G-CEM ONE without AEP. Group III: A customized (GF) post was cemented by G-CEM ONE with AEP. Group IV: A customized (GF) post was cemented by G-CEM ONE without AEP. (n = 10 for each group). The PBS was tested with a universal testing machine, and the values were analyzed with (ANOVA) and Tukey's post hoc test at a P ≤ 0.05 significance level.

Results

Group III revealed the greatest PBS values, followed by Group IV, Group I, and finally, Group II showed the lowest PBS values. The coronal root slices showed the highest PBS in comparison with the middle and apical third.

Conclusion

The touch-cure polymerization improved the PBS of the prefabricated and customized fiber posts. Therefore, ‟touch and cure" cement may be considered a clinical alternative to conventional types of resin cement. The customized (GF) posts exhibited a higher PBS than the prefabricated (GFRC). The combination of customized posts and G-CEM ONE with AEP is recommended as a new strategic approach to improve interfacial adhesion.

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.

Influence of Lithium disilicate pretreatment using photodynamic therapy, non-thermal plasma, and laser treatment on surface roughness and bond strength

AIMS

To assess the shear bond strength (SBS) and surface roughness (Ra) of lithium disilicate ceramic (LDC) after using different pretreatment methods i.e., Non-Thermal Plasma (NTP), self-etching ceramic primer (SECP), curcumin photosensitizer (CP), Er and Cr: YSGG lasers (ECL) in comparison to hydrofluoric acid + Silane (HF + S) MATERIALS AND METHODS: : A total of fifty LDC discs were prepared. All the discs were arbitrarily divided into five groups based on the surface conditioning used (n=10). Group 1: PDT+S, group 2: HF+ S, group 3: NTP + S, group 4: SECP, and group 5: ECL+ S. A confocal optical microscope was used to calculate Ra for each sample. A self-adhesive resin cement was applied followed by LED light curing. A universal testing machine was used to assess SBS and a stereomicroscope was used to determine the failure mode. Two-way analysis of variance (ANOVA), and a Tukey post hoc test was used to analyze data (p=0.05) RESULTS: : The highest bond integrity of resin luting bonded to conditioned LDS ceramics were presented by group 2 (HF+ S) (21.48±1.39 MPa) and lowest by group 1 (CP+S) (13.01±1.19 MPa) respectively. Intergroup comparison analysis revealed that group 1(13.01±1.19 MPa) and group 3 (14.28±0.62 MPa) displayed comparable outcomes of bond integrity(p>0.05). Similarly, it was observed that group 2 (21.48±1.39 MPa) and group 5 (21.31±1.85MPa) exhibited comparable values of bond strength(p>0.05). Specimens conditioned with HF+ S showed the highest Ra (1445.86±0.019µm). However, discs treated with SECP exhibited the lowest Ra (0139.76±0.081µm) CONCLUSION: Er, Cr: YSGG laser retains the ability to be used as an LDC surface conditioner as an alternative to HF+ S.Both the methods of pretreatment results in high surface roughness of LDC.

Bond strength and failure mode of glass fiber posts with different surface treatments prior to silanization: An in vitro comparative study

Aim

The use of chemical agents in the surface treatment of glass fiber posts can improve their bond strength to the root canal. The aim of this study was to assess the bond strength and failure mode of glass fiber posts that received different surface treatments prior to silanization.

Materials and Methods

In this cross-sectional and in vitro experimental study, 50 human lower premolar roots were randomly divided into five groups and subsequently prepared to receive the cementation of a fiberglass post prior to silanization. They were distributed as group 1 (with 24% hydrogen peroxide), group 2 (with 37% phosphoric acid), group 3 (with 1.23% acidulated phosphate fluoride for 2 minutes), group 4 (with 1.23% acidulated phosphate fluoride for 6 minutes), and group 5 (without pretreatment). After cementation, the roots were sectioned into two discs for each cervical, middle, and apical region. Bond strength was assessed using the push out technique. Adhesive, mixed, and cohesive failure modes were also assessed. For data analysis, ANOVA and Tukey's post hoc tests were used, as well as Pearson's chi-square test. A significance of P < 0.05 was considered in all statistical analyses.

Results

When comparing the bond strength of root regions, significant differences were obtained in groups pretreated with phosphoric acid (P = 0.018) and acidulated phosphate fluoride for 2 and 6 minutes (P = 0.001 and P = 0.000, respectively). Furthermore, significant differences were obtained between posts treated only with silane and those that received phosphoric acid pretreatment (P = 0.006) and acidulated phosphate fluoride for 6 minutes (P = 0.001). Significant association of mixed failure mode was observed with hydrogen peroxide (P = 0.014) and phosphoric acid (P = 0.006) pretreatments. Cohesive failure was significantly associated with acidulated phosphate fluoride pretreatment for 2 minutes (P = 0.032) and with posts that did not receive treatment prior to silanization (P = 0.000).

Conclusion

Posts treated only with silane and pretreated with hydrogen peroxide and acidulated phosphate fluoride for 2 minutes presented significantly higher bond strength with respect to those pretreated with phosphoric acid and acidulated phosphate fluoride for 6 minutes. However, acidulated phosphate fluoride for 2 minutes and silane were associated with a better bonding type.

Push-out bond strength and failure mode of single adjustable and customized glass fiber posts

Purpose

To evaluate the push-out bond strength (PBS) and failure mode of single adjustable (SAP) and customized (CP) posts cemented to root canal dentin using conventional (RelyX Ultimate) or self-adhesive (RelyX U200) dual-cure resin cements.

Methods

Herein, 40 bovine mandibular incisors were divided into four groups (n = 10): SAP cemented with RelyX Ultimate (SAP-UT), SAP cemented with RelyX U200 (SAP-U2), CP cemented with RelyX Ultimate (CP-UT), and CP cemented with RelyX U200 (CP-U2). PBS and failure modes were analyzed. Three-way repeated measures ANOVA test followed by Tukey’s test and Fisher–Freeman–Halton exact test were used for data analysis (α = 5%).

Results

The PBS values for SAP (p < .05) were higher than those for CP and were not influenced by the root third and resin cement (p > .05). When conventional resin cement was used, the SAP showed significant differences compared to CP (p < .05). When cemented with RelyX Ultimate, a higher prevalence of mixed and adhesive failures for SAP and CP, respectively, was observed (p < .05). For the self-adhesive resin cement, the failures were mostly adhesive (p < .05).

Conclusion

SAP showed better performance than CP. The root third and resin cements did not influence the PBS. The most prevalent failures were adhesive and mixed.

Effect of Luting Cement Film Thickness on the Pull-Out Bond Strength of Endodontic Post Systems

Optimal bond strength between the prefabricated post/dowel to the surrounding dentin is essential. The present study aimed to analyze and compare the effect of three different cement film thicknesses on the pull-out bond strength of three different prefabricated post systems. Extracted natural teeth (N = 90) with similar root dimensions were acquired. Teeth were mounted in resin blocks, endodontically treated, sectioned at cemento-enamel junction, divided into three groups (A: Parapost Fiber Lux plus; B: 3M ESPE Relyx fiber post; and C: Parapost XP), and stored. Uniform post spaces were prepared for the groups (A and C: Length = 8 mm, Width = 1.5 mm; B: Length = 8 mm, Width = 1.6 mm). Each group (N = 30) was further subdivided into three subgroups (n = 10) based on the size (4, 5, and 6) of the post and cemented with resin cement (MultiLink-N, Ivoclar Vivadent). After thermocycling, the specimens were subjected to a pull-out test using a universal testing machine, and tensile force was recorded (MPa). Digital microscopic evaluations were performed for modes of failure. ANOVA and Tukey-HSD tests were used for statistics. Significant differences were observed for each tested material (p = 0.000). The lowest and highest bond strength values were recorded for Group C (Titanium post) and Group A (000), respectively. Multiple comparisons showed significance (p < 0.05) among all the groups, except for space 1 and space 2 (p = 0.316) for Group A. Most of the failures occurred within the cement-dentin and post-cement interface (Adhesive failures, 73.5%). An increase in the luting cement film thickness results in the decrease in pull-out bond strength of prefabricated posts luted with resin cement, irrespective of the type/material/shape of the post. The serrated fiber posts showed the highest pull-out bond strength compared to the smooth surfaced fiber posts or serrated metal posts. Increased pull-out bond strengths were observed when appropriate post space was created with the same sized drill as the post size.

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.