Effect of Er,Cr:YSGG pretreatment on bond strength of fiber posts to root canal dentin using a self-adhesive resin cement

Effect of Laser Treatment of Root Dentine on Retention of Dental Fiber Post in Endodontically Treated Teeth: An In Vitro Study

Introduction: The most common causes of fiber post-failure are inadequate restorations and dislodgement. This study aimed to evaluate fiber post-bond strength to dentin following Er,Cr:YSGG laser irradiation. Methods: A total of 65 human mandibular premolars with single roots were included. The 14 mm root length was instrumented with the rotary system using the crown-down technique. Gutta-percha was used for obturation, followed by conventional post space preparation. The samples were divided into two major groups: control (A) and Er,Cr:YSGG (2780 nm) laser group (B). The laser group was subdivided into (B1) 1.25 W, (B2) 1.5 W, and (B3) 1.75 W. All laser groups were set at 20 Hz, 10% and 30% water/air ratio. Fiber posts were cemented with selfadhesive cement. Each sample was divided horizontally into two slices, coronal and apical. The universal testing equipment was used to conduct a push-out test. All groups were examined by SEM and temperature changes. The statistical analysis was performed by using one-way ANOVA and Tukey HSD tests. Results: SEM images of all laser groups revealed the elimination of the smear layer and opened dentinal tubules, which was particularly noticeable in the apical region with no thermal risk to the periodontal tissue. In the push-out test, all laser groups had highly significant (P<0.001) increases in the bond strength of fiber post to dentin. The failure mode of the control group was a predominantly adhesive failure, whereas the laser groups were a predominantly mixed type. Conclusion: The three laser protocols can be used safely in the surface treatment of the fiber post space of endodontically treated teeth. Laser help to increase the bond strength of fiber post to dentin, especially in the apical area.

Photon-Induced Photo-Acoustic Streaming vs. Shock Wave-Enhanced Emission Photo-Acoustic Streaming-The Effect of Three Final Irrigation Protocols on the Bond Strength of an Individually Formed Fiber Post

(1) Background: This study aimed to evaluate how laser-activated irrigation (LAI) influences the retention of a fiber post when used before an endodontic filling, as well as after post space preparation. (2) Materials and Methods: Sixty freshly extracted human incisors were selected. The teeth were randomly assigned to three groups-CONVENTIONAL (CONV), PIPS or SWEEPS-and treated endodontically. Each group received irrigation with 1 × 5 mL EDTA (17%) and 3 × 5 mL NaOCl (5.25%). In the first group, the irrigants were not activated, while in the second and third group, LAI was adopted using PIPS and SWEEPS protocols (Lightwalker from Fotona, Ljubliana, Slovenia). After post space preparation, each group received the same irrigation protocol initially established. Sticky posts (everStick Post, GC AUSTRIA GmbH Swiss) were individually adapted to the corresponding post spaces and cemented using dual cure resin cement (Gradia Core, GC Austria GmbH Swiss). All specimens were vertically embedded into self-curing acrylate (Duracryl plus, Spofa Dent, Europe), and each was sectioned into three segments of type A and type B samples for debonding through push-out and pull-out tests. The results were statistically analyzed. (3) Results: The pull-out test showed the superiority of the SWEEPS group, with a mean fracture force of 133.0 ± 50.7 N, followed by the PIPS group, with 102 N, with a lower standard deviation of ± 34.5 N. The CONV group registered the lowest fracture force. Concerning the push-out test, the SWEEPS group showed superior shear stress in comparison to the other two groups (13.45 ± 4.29 MPa); the CONV group was inferior, with shear tension values of 8.31 ± 4.67 MPa. (4) Conclusions: It can be stated that the SWEEPS and PIPS protocols resulted in considerably higher fiber post retention than the conventional method, whereas the SWEEPS protocol was superior to the PIPS protocol.

Post-Space Treatment Influences the Bond Strength In Endodontically Treated Teeth: A Systematic Review and Meta-Analysis of In Vitro Studies

OBJECTIVES

This systematic review of in vitro studies investigated the influence of the post-space treatment used to remove the smear layer on the bond strength of the post to root canal dentin.

METHODS AND MATERIALS

In vitro studies included in this study were identified from PubMed/MEDLINE, Lilacs, and Scopus databases up until March 2019, without limits on publication year or language. Two reviewers independently selected the studies based on the inclusion and exclusion criteria, extracted the data, and evaluated the risk of bias of all studies. A random effects model was used for pairwise meta-analyses (control vs. post-space preparation groups) at a significance level of p<0.05.

RESULTS

Of the 2,832 potentially eligible studies, 453 studies were selected for full-text analysis, and 75 were included in this systematic review. Only one study was considered to have a low risk of bias. Overall, post-space treatment significantly improves the bond strength to root canal dentin (p<0.00001).

CONCLUSION

Post-space treatment has a positive influence on the bond strength of the post to root canal dentin. In this review, the post-space treatments that improve the adhesive resistance of the post were ethanol, sodium hypochlorite, and ethylene diamine tetra-acetic acid (NaOCl + EDTA), NaOCl + EDTA + ultrasound, erbium-doped yttrium aluminium garnet laser (Er:YAG laser), neodymium-doped yttrium aluminium garnet laser (Nd:YAG laser), and diode laser.

Effect of different laser types on bonding strength of CAD/CAM-customized zirconia post to root canal dentin: an experimental study

In clinical dentistry, the strength of bonding zirconia posts to root canal dentinal walls currently needs enhancement, and laser application can be an important contribution owing to its features that accommodate adjustable modifications on dental materials. Herein, the effect of different laser treatments applied to dentin surfaces on the strength of bonding zirconia posts to root canal dentinal walls is evaluated by using the pull-out bond strength test in a laboratory setting. A total of 40 single-rooted permanent mandibular premolar teeth that were freshly extracted were used here. The root canal preparation steps were performed using the crown-down technique. Custom-made zirconia posts were produced using CAD/CAM technology. Prior to the application of resin cement, the internal surfaces of the root canals were irradiated using Nd:YAG, Er:YAG, and KTP lasers. Pull-out tests were performed on each specimen by using a universal testing machine. One-way analysis of variance and Tukey post hoc tests were used to compare the pull-out bond strength data. The bond strengths of the laser-treated specimens were greater than those of the untreated controls (p < 0.05). While the value of the pull-out bond strength after Nd:YAG laser treatment was significantly higher than the values obtained after the applications of the Er:YAG and KTP lasers (p < 0.05), the pull-out bond strength after Er:YAG laser treatment was considerably greater than that after KTP laser treatment (p < 0.05). The bond strength between the root canal dentin and the CAD/CAM custom-made zirconia post was improved upon using all the laser modalities in current laboratory settings, among which, application of the Nd:YAG laser was the most successful.

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.

Efficacy of phototherapy in the adhesive bonding of different dental posts to root dentin: A systematic review

BACKGROUND

The aim of the current systematic review was to evaluate the efficacy of phototherapy in the adhesive bonding of different dental posts to root dentin.

METHODS

The outline of this systematic review followed the PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analysis) guidelines. Searches in both electronic and manual literature were performed in the main databases 'MEDLINE' and 'EMBASE' up to March 2019 using the following terms: (Phototherapy) AND (push out test) AND (bond strength) AND (post) OR (fibre) OR (metal) AND (smear layer).

RESULTS

Six in-vitro studies were included and processed for data extraction. All studies incorporated the use of fiber posts. The mean shear bond strength for test group ranged from 2.23 to 15.17 MPa while mean shear bond strength for control group ranged from 2.93 to 9.38 MPa. The wavelengths of diode lasers ranged from 660 to 2940 nm (nm). Power was reported in 5 studies ranging from 0.075 W to 3 W. All studies compared shear bond strength of phototherapy in the adhesive bonding of different dental posts to root dentin. In all the included studies, greater bond strength achieved by phototherapy compared to nonirradiated group.

CONCLUSION

Within the limits, this study shows that the dentin to post bond strength was significantly enhanced by phototherapy.

Effect of Laser Etching on Glass Fiber Posts Cemented with Different Adhesive Systems

BACKGROUND

Glass fiber-reinforced posts have been preferred frequently because of some physical properties similar to the dentin, chemically bonding to dentin, biocompatibility, and esthetics.

OBJECTIVE

This study aimed to evaluate the microleakage and bond strength of glass fiber posts cemented with various adhesive systems on laser-etched root canal walls.

METHODS

Roots of 120 human mandibular premolars were divided into two groups for push-out bond strength test and the microleakage test (n = 60). Erbium-doped yttrium-aluminum-garnet (Er:YAG) laser etching of the root canal walls was carried out on half of the specimens in both test groups. The laser-treated and laser-nontreated groups were divided again into three subgroups (n = 10). Glass fiber posts (everStick Post) were luted using three different resin cements: total-etch (Variolink N), self-etch (Panavia F 2.0), and self-adhesive (Rely X Unicem). Three dentin discs were obtained from each root, and the bond strength of the glass fiber posts was measured by push-out tests. The dye penetration method was used to investigate coronal microleakage. In addition, surface treatments and the bonding interfaces were observed using scanning electron microscope.

RESULTS

The highest bond strengths were observed for the total-etch and self-adhesive resin cement groups with laser etching (p < 0.05), and the lowest bond strength was obtained for the self-etch resin cement group (p < 0.05). There were no statistically significant differences in terms of microleakage (p > 0.05), except for the self-adhesive resin cement group (p < 0.05).

CONCLUSIONS

Er:YAG laser etching enhances the bonding strength of glass fiber posts. In addition, laser etching can reduce microleakage of self-adhesive resin cement.

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.

Effects of dentin surface treatments including Er,Cr:YSGG laser irradiation with different intensities on the push-out bond strength of the glass fiber posts to root dentin

OBJECTIVE

Intra-canal post systems are commonly used to restore root-filled teeth. Bond strengths of the posts can be affected by various surface treatments of the post or the dentin. The aim of this study was to evaluate the effects of dentin surface treatments including erbium-chromium; yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser irradiation with different intensities on the push-out bond strength of the glass fiber posts to root dentin.

MATERIALS AND METHODS

Forty single-rooted human maxillary incisors were filled and post spaces were prepared. After these procedures, the specimens were divided randomly into four groups according to the dentin surface treatments, as follows: (i) untreated surface (control), (ii) 1W Er,Cr:YSGG laser application, (iii) 2W Er,Cr:YSGG laser application and (iv) 3W Er,Cr:YSGG laser application. Then the posts were cemented into the root canals using dual-cured resin cement. Bonded specimens were cut into 1-mm-thick slices and push-out tests were performed using a universal testing device. All specimens were loaded until fracture and the failure modes were evaluated with a stereomicroscope at 32× magnification. Representative specimens were analyzed by scanning electron microscopy. Data were analyzed using a one-way ANOVA, Tukey and Wilcoxon tests.

RESULTS

The bond strength values ranged from 3.22-4.68 MPa. There were no statistically significant differences among the groups, regardless of the different levels. The coronal and middle levels of the post space had significantly higher bond strength values compared with the apical level (p < 0.05).

CONCLUSION

Er,Cr:YSGG laser irradiation with different intensities did not increase the bond strength of the fiber posts to the root canal dentin walls.