Adhesion between glass fiber posts and resin cement: evaluation of bond strength after various pre-treatments

Push-out bond strength of various surface treatments on fiber post to root canal dentine using different irrigation techniques

To compare the efficacy of different surface treatments (fiber post) with laser activated irrigation (LAI) technique (various root canal solutions) on root canal dentine in terms of push-out bond strength (PBS) in a fiber post. In this study, 200 premolars were assigned into groups according to various irrigation techniques: 2.5% sodium hypochlorite (NaOCl), 17% ethylene diamine tetra acetic acid (EDTA), and 17% EDTA + LAI. In addition, the fiber posts were separated into five groups, (n = 30) according to the surface pretreatment performed: sandblasting, hydrofluoric acid (HF), Erbium, Chromium:Yttrium Scandium-Gallium-Garnet (Er,Cr:YSGG) laser, Neodymium-Doped Yttrium Aluminum Garnet (Nd,YAG) laser and as untreated surface. The posts were cemented using dual-cure resin cement and subjected to a PBS test. Data were analyzed by one way-ANOVA, Tukey, and Tamhane T2 tests. The PBS values were increased in all parts of the tooth in the EDTA and EDTA + LAI treated groups and in groups treated with Er,Cr:YSGG laser fiber posts. In groups in which EDTA and EDTA + LAI were applied, it was observed that dentinal tubules were open according to the distribution and number of dentinal tubule configurations. The improvement of the PBS between fiber post/resin cement/root dentine was observed via the use of fiber post surface treatments with different irrigation techniques.

Laser Treatment of Fiber Post and Final Push-Out Bond Strength: A Systematic Review and Meta-Analysis

Purpose: This review article tries to answer this question: "What are the effects of laser surface treatment of fiber posts (FPs), compared with other surface roughening methods, on bond strength of cemented FPs?" Methods: Search was carried out in six electronic databases by focusing on defined key words. Related titles and abstracts, up to March 2019, were collected, read, and selected for quality assessments. A total of 2408 articles were included in the study at the initial stage of the searching phase. Results: Finally, seven studies were recognized to be reliable to be reviewed and meta data analysis in the study. All the studies were in vitro with a total of 340 samples. None of the Er:YAG (-0.27, 95% CI: -2.29 to 1.76; p = 0.79) and Er,Cr:YSGG (-0.04, 95% CI: -1.43 to 1.35; p = 0.95) treated samples showed any significant overall mean differences in final push-out bond strength (PBS) compared with the control groups. Conclusions: Laser pretreatment of FP surfaces might not be effective in providing high PBS. FP surface are susceptible to damage of high-level laser irradiation and might show decreased bond strength.

Mechanical properties of glass-fibre-reinforced composite posts after laser irradiation with different energy densities

The aim of the present study was to evaluate the effect of the surface treatments on flexural strengths and flexural modulus of glass-fibre-reinforced composite (GFRC) posts. Sixty-three posts were randomly divided into 9 groups (n = 7), and various surface treatments were performed. The control group was left untreated. Other groups were treated with 9% hydrofluoric acid, sandblasting with 120 µm Al₂ O₃ particles and Er,Cr:YSGG laser irradiation with different powers (1 W, 2 W, 3 W, 4 W, 5 W and 6 W). The samples were subjected to 3-point bending test, and data were calculated. Statistical analysis was performed. The flexural strengths of fibre posts treated with sandblasting, hydrofluoric acid, 1 W and 2 W laser were statistically similar with control group (P > 0.01). However, the flexural strength of fibre posts treated with 3 W, 4 W, 5 W and 6 W laser was statistically lower than control group (P < 0.01). High laser irradiations cause melting on the post surface and breaks in fibrils.

Effects of motion direction and power of Er,Cr:YSGG laser on pull-out bond strength of fiber post to root dentin in endodontically-treated single-canal premolar teeth

Background

Inadequate retention and gradual debonding of intracanal post from root dentin is a major cause of failure of endodontically treated teeth restored with fiber post.

Main body

This study aimed to assess the effect of surface treatment of quartz fiber posts with different powers and motion directions of Er,Cr:YSGG laser on their pull-out bond strength to root dentin in endodontically treated premolar teeth. In this study, 105 fiber posts were divided into 7 groups according to their surface treatment with different powers of Er,Cr:YSGG laser at 2780 nm wavelength, 20 Hz frequency and 150 μs pulse duration in circumferential (C) or longitudinal (L) motion directions: Control group (no treatment), 0.5 W laser in longitudinally (L0.5), 1.0 W laser in longitudinally (L1), 1.5 W laser in longitudinally (L1.5), 0.5 W laser in circumferentially (C0.5), 1.0 W laser in circumferentially (C1) and 1.5 W laser in circumferentially (C1.5). After cementation, pull-out bond strength was measured in Newton (N). Each sample was inspected under a stereomicroscope at × 25 magnification to determine the mode of failure. Two samples of each group were inspected under a scanning electron microscope (SEM). Data were analyzed using two-way ANOVA and Tukey’s test with significant level of 0.05. The pull-out bond strength of 0.5 W groups had significant differences with the control group (P = 0.009). The bond strength of 1.0 W and 1.5 W groups were not significantly different (P = 0.630) but were higher than the control and 0.5 W groups (P < 0.001). Motion direction of laser irradiation had no significant effect on the bond strength (P = 0.384). The interaction effect of power and motion direction of laser irradiation had no significant effect on the bond strength (P = 0.092).

Conclusion

Fiber posts treated with 0.5, 1.0 and 1.5 W Er,Cr:YSGG laser showed higher bond strength to dentin compared to posts with no surface treatment. However, the motion directions of laser irradiation had no significant effect on the bond strength. In order to minimize damage to post surface and achieving maximum bond strength, longitudinal surface treatment of posts with 1.0 W power of Er,Cr:YSGG laser is recommended.

The Effect of Diode and Er,Cr:YSGG Lasers on the Bond Strength of Fiber Posts

Background: Laser irradiation modifies the topography and composition of dentin surface aiming to increase the retention of bonded posts. Objective: To assess the effect of dentin irradiation with Er,Cr:YSGG or diode lasers on the bond strength of fiber posts using self-adhesive resin cement. Materials and methods: Sixty bovine root canals were root-canal treated, post spaces were prepared, and subsequently fiber posts were cemented. The samples were distributed according to the surface treatment: distilled water (control), Er,Cr:YSGG (1.5 W, 20 sec), or diode (1.5 W, 20 sec) lasers. Bond strengths were assessed by pull-out (n = 10) or push-out testing (n = 10). Pearson's correlation was calculated. Failure mode after testing and the depth of tags in the dentinal tubules were analyzed by confocal laser microscopy. Data were submitted to analysis of variance and Tukey's test. A p < 0.05 was considered significant. Results: In the push-out test, Er,Cr:YSGG laser had significantly different higher values (5.43 ± 0.10 MPa) compared to the control (4.79 ± 0.05 MPa). Diode laser values were not significantly different from the other groups (5.12 ± 0.27 MPa). In the pull-out test, there were no significant differences between Er,Cr:YSGG (6.86 ± 2.16 MPa) and diode (8.43 ± 1.77 MPa) lasers, and both had significant differences compared to the control (4.18 ± 1.29 MPa). No correlation was found. Adhesive failures were predominant in all groups, and no significant differences in tag penetration among the groups were found. Conclusions: The Er,Cr:YSGG laser increases the bond strength of resin cement and fiber post to dentin in both tests, compared to control group without laser treatment. Diode laser only enhanced bonding for pull-out test.

Irrigación del conducto radicular y tratamiento de superficie de pernos de fibra, previo a la cementación: revisión de tema

Introducción: el tratamiento endodóntico es muy solicitado para preservar las piezas dentales, así como la utilización de pernos de fibra cuando el remanente coronario no es el adecuado para recibir una prótesis coronaria, permitiendo de esta manera reconstruir el muñón dental para la posterior colocación de la restauración definitiva. Objetivo: identificar tanto el tratamiento de superficie de pernos de fibra como el irrigante radicular idóneos para conseguir una cementación adecuada; así como conocer cuál es el tratamiento de superficie que produce menos desintegración de las fibras del perno de fibra. Materiales y métodos: se incluyeron 47 artículos publicados en inglés, durante los últimos 20 años, teniendo en cuenta que los mismos se obtuvieron hasta octubre del 2018. Conclusiones: previa la cementación de pernos sean estos de fibra o de cuarzo es indispensable realizar tratamiento de superficie para así mejorar la adhesión, estos pueden ser químicos o físicos, los que ofrecen mejor resultado sin alterar de manera significativa la estructura del mismo es el enarenado con partículas de diamante sintéticas de 1-3 µm seguido de silanización y dentro de los químicos H2O2 al 10% por 1 min seguido de silano. Para obtener mejores resultados se debe accionar el silano a una temperatura de 80°C. En cuanto a protocolos de irrigación depende del sistema de cementación que se vaya a emplear EDTA 18% + Hipoclorito de sodio al 5,25% o EDTA 18% + clorhexidina al 2% cuando se va emplear un cemento autoadhesivoy NaOCl al 11% cuando se utilice el acondicionamiento ácido de lavado y secado.

Bond Strength of Fiber Posts to Composite Core: Effect of Surface Treatment With Er,Cr:YSGG Laser and Thermocycling

Introduction: This study aimed to determine the bond strength of fiber post to composite core following surface treatment with Er,Cr:YSGG laser at different powers and sandblasting with and without thermocycling. Methods: In this experimental study, 30 fiber posts (Glassix, Nordin, Switzerland) were randomly divided into 5 groups of sandblasting, no treatment and laser irradiation at 1, 1.5 and 2 W powers. Following composite filling and mounting, 1-mm thick sections were made for pushout bond strength testing. Half of the samples in each group were subjected to thermocycling (n=15). Two-way analysis of variance (ANOVA) was used to analyze the bond strength values. Pairwise comparisons were made using Tukey test (P<0.05). Results: Effect of treatment method on push-out bond strength of fiber post to composite core was significant (P=0.017), while thermocycling had no significant effect on bond strength (P=0.964). Pairwise comparison of surface treatment methods revealed no significant difference in groups with and without thermocycling (P>0.05), but Er,Cr:YSGG laser irradiation with 1 W power yielded significantly higher bond strength than the control group (P=0.01). Conclusion: Irradiation of Er,Cr:YSGG laser at 1 W power increased the bond strength of fiber post to composite core. Thermocycling slightly decreased the bond strength at the fiber postcore interface.

Influence of laser irradiation on the push-out bond strength between a glass fiber post and root dentin

STATEMENT OF PROBLEM

A major issue related to the failure of endodontically treated teeth restored with an intraradicular post is gradual debonding of the glass fiber post, resin cement, and dentin.

PURPOSE

The purpose of this in vitro study was to evaluate the influence of laser irradiation on the push-out bond strength of glass fiber posts to radicular dentin.

MATERIAL AND METHODS

Thirty-two mandibular bovine incisors were endodontically treated and divided into 4 groups according to the surface treatment of the post: silane control (GC); irradiation with Er:YAG (GYAG); irradiation with Er,Cr:YSGG (GCR); and 980-nm diode laser (GDI) application. After surface treatment, the glass fiber posts were cemented with dual adhesive resin cement. To evaluate bond strength, the specimens were subjected to a push-out test at a crosshead speed of 0.5 mm/min using a universal testing machine. Failure mode was analyzed using stereomicroscopy. The surface morphology was evaluated qualitatively after surface treatment by using confocal laser microscopy. The push-out test data (MPa) were analyzed using a linear mixed effects model and the Bonferroni test (α=.05).

RESULTS

At the cervical third, no significant differences were observed between the GC and GCR groups (P=1.00), and both of the groups exhibited higher bond strength. At the middle and apical thirds, the GCR group revealed higher bond strength, which was significantly different from that observed in all other groups (P<.05). No statistical differences were observed among the other tested protocols (GC, GYAG, and GDI groups; P=1.00). Adhesive failure was predominant in all groups.

CONCLUSIONS

Irradiation with Er,Cr:YSGG improved the bond strength of the cement-post-dentin interfaces.

Evaluation of Mechanical Properties of Glass Fiber Posts Subjected to Laser Surface Treatments

OBJECTIVE

The aim of this study was to evaluate the influence of laser irradiation on flexural strength, elastic modulus, and surface roughness and morphology of glass fiber posts (GFPs).

BACKGROUND DATA

Laser treatment of GFPs has been introduced to improve its adhesion properties.

MATERIALS AND METHODS

A total of 40 GFPs were divided into 4 groups according to the irradiation protocol: GC-no irradiation, GYAG-irradiation with erbium:yttrium-aluminum-garnet [Er:YAG], GCR-irradiation with erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG), and GDI-irradiation with diode laser. The GFP roughness and morphology were evaluated through laser confocal microscopy before and after surface treatment. Three-point bending flexural test measured flexural strength and elastic modulus. Data about elastic modulus and flexural strength were subjected to one-way ANOVA and Bonferroni test (p < 0.05). The effect of roughness was evaluated using the linear mixed effects model and Bonferroni test (p < 0.05).

RESULTS

Laser treatment changed surface roughness in the groups GCR (p = 0.000) and GDI (p = 0.007). The mean flexural strength in GYAG (995.22 MPa) was similar to that in GC (980.48 MPa) (p = 1.000) but different from that in GCR (746.83 MPa) and that in GDI (691.34 MPa) (p = 0.000). No difference was found between the groups GCR and GDI (p = 0.86). For elastic modulus: GYAG (24.47 GPa) was similar to GC (25.92 GPa) (p = 1.000) but different from GCR (19.88 GPa) (p = 0.002) and GDI (17.20 GPa) (p = 0.000).

CONCLUSIONS

The different types of lasers, especially Er,Cr:YSGG and 980 ηm diode, influenced the mechanical properties of GFPs.

Comparison of the effect of shear bond strength with silane and other three chemical presurface treatments of a glass fiber-reinforced post on adhesion with a resin-based luting agent: An in vitro study

Background:

Loss of retention has been cited to be the most common cause of the failure of postretained restoration with irreversible consequences when materials with different compositions are in intimate contact at the post/adhesive interface. With this background, a study was conducted to improve the adhesion at the resin phase of fiber posts using silane and other chemical pretreatments.

Materials and Methods:

Hundred glass fiber-reinforced posts were tested with 4 different protocols (n = 25) using silane as a control (Group A) and other three experimental groups, namely, Group B-20% potassium permanganate, Group C-4% hydrofluoric acid, and Group D-10% hydrogen peroxide were pretreated on the postsurface followed by silanization. These specimens were bonded with dual-polymerizing resin-based luting agent, which were then loaded at the crosshead speed of 1 mm/min to record the shear bond strength at the post/adhesive interface. The data were analyzed using one-way ANOVA test for multiple group comparisons and the post hoc Bonferroni test for pairwise comparisons (P < 0.05).

Results:

Group B showed more influence on the shear bond strength when compared to other protocols, respectively (P < 0.001).

Conclusion:

Alone silanization as a surface treatment did not improve the bond strength. Combination of chemical presurface treatments followed by silanization significantly enhanced the bond strength at the post/adhesive interface.

Light transmittance of fiber posts following various surface treatments: A preliminary study

OBJECTIVE

The objective of this study was to compare the light transmittance of fiber posts following application of various surface treatments.

MATERIALS AND METHODS

Fiber post specimens (Snowpost red size #14) were tested (n = 7). The fiber posts were divided into five groups according to the application of surface treatments: Group 1: No surface treatment; Group 2: Etched with hydrofluoric acid (HF) + silane application; Group 3: Airborne-particle abraded with 110 μm Al2O3; Group 4: Irradiated with erbium: Yttrium-aluminum-garnet laser; Group 5: Airborne-particle abraded with 110 μm Al2O3 + silane application. The light transmittance of the specimens was compared using a spectrophotometer. Statistical significance was determined using one-way analysis of variance (ANOVA) (α = 0.05).

RESULTS

One-way ANOVA revealed that surface treatment had significant effects on light transmittance of posts (P < 0.001). While laser treatment had the highest percentage of light transmittance, treatment with silane following HF application had the lowest.

CONCLUSION

Application of surface treatments might negatively affect the light transmission property of fiber posts.