Effect of different irrigant activation protocols on push-out bond strength

Influence of irrigation and laser assisted root canal disinfection protocols on dislocation resistance of a bioceramic sealer

BACKGROUND

It is not yet clear how different irrigation protocols and intracanal laser irradiation effects bioceramic sealers. In this vitro study, we aimed to evaluate the dislocation resistance of a bioceramic root canal sealer after different laser-assisted disinfection protocols and irrigants.

METHODS

Sixty extracted human straight single-canal teeth were instrumented, and randomly divided into five experimental groups (n=10) according to the disinfection protocol used: group 1, conventional needle irrigation (CI) with sodium hypochlorite (NaOCl)+ethylenediaminotetraacetic acid (EDTA)+NaOCl; group 2, Photon initiated photoacoustic streaming (PIPS) of NaOCl+EDTA+NaOCl; group 3, NaOCl+EDTA+diode laser; group 4, NaOCl+EDTA+photodynamic therapy (PDT); group 5, CI with NaOCl+EDTA+Chlorhexidine (CHX); and control group without any treatment. The root canals were filled with a bioceramic root canal sealer (BioRoot RCS) using the single-cone filling technique. After three weeks of storage, the samples from each canal thirds were transversely sectioned and the push-out test was performed.

RESULTS

The PIPS group showed the lowest dislocation resistance values in the coronal third (p>0.05), and no difference was observed among the other groups (p<0.05). The dislocation resistance in the middle and apical thirds was the highest in the diode laser group (p<0.05).

CONCLUSION

Final root canal irradiation with diode laser led to improved dislocation resistance of the bioceramic sealer. PDT did not adversely affect the dislocation resistance of BioRoot RCS. The PIPS reduced the dislocation resistance values in the coronal third, but not in the middle and apical thirds.

Efficacy of Photoinduced Photoacoustic Streaming and Diode Laser Irrigation Techniques on Smear Layer Removal, Sealer Penetration and Push-out Bond Strength

Introduction: The present study aimed to test the efficiency of photoinduced photoacoustic streaming using 2940 nm Er: YAG laser and 980 nm diode laser agitation on smear layer removal, sealer penetration and push-out bond strength. Methods: Sixty single canaled human permanent teeth were collected for this study. Specimens were grouped into three experimental groups (20 teeth in each group), depending on the activation protocol used for final irrigation: Group I (needle agitation), group II (980nm diode laser agitation) and group III (photon induced photoacoustic streaming (PIPS) using 2940 nm Er: YAG laser. The quantity of irrigant was standardized in all groups to 4 ml. The irrigant was activated for 40 seconds in different groups under continuous flow. Two teeth from each group were used to check the smear layer removal, and then the remaining teeth in each group were randomly divided into three equal experimental subgroups according to methods of evaluation used: subgroup A: Sealing ability evaluated by dye penetration method; subgroup B: SEM for sealer penetration; and subgroup C: Push-out bond strength assessed by the universal test machine. Results: As regards smear layer removal, results showed that the PIPS group had opened dentinal tubules, followed by the diode laser group, while the least cleaning effect was found in the Side-vented needle group. As for Sealing ability and dye penetration, a statistically significant difference was found between all of the three groups, with the Er:YAG laser (PIPS) having the best sealing ability and sealer penetration. Push-out bond strength results showed no statistically significant difference between diode and Er:YAG groups, with a significant difference between each of them and the Side-vented needle group. Conclusion: Using the diode or Er:YAG laser (PIPS) for irrigant activation led to better irrigant penetration and smear layer removal which subsequently led to obvious sealer penetration, better sealing, and strength properties of endodontic treated teeth.

Effect of Er:YAG laser irrigation with different etching modes on the push-out bond strength of fiber posts to the root dentine

The objective of this study was to evaluate the effect of Er:YAG laser irrigation on the push-out bond strength of fiber posts to the root dentine. Sixty extracted human mandibular first premolars were collected and decoronated. The residual roots received endodontic treatment. The treated roots were randomly divided into three groups according to different irrigation protocols: group LAI (Er:YAG laser–activated irrigation), group PUI (passive ultrasonic irrigation, positive control), and group CSI (conventional syringe irrigation, negative control) (n = 20). Each group was divided into two subgroups, either total-etching modes or self-etching modes (n = 10). After fiber post restoration, all roots were sectioned into seven 1.0-mm-thick slices. The slices received a push-out test by a universal test machine. The resin tag on the segments’ bonding interfaces was observed by scanning electron microscope. There were significant differences in the effects of the irrigation method, bonding modes, and root regions on the push-out bond strength among the groups (p < 0.05). The specimens with Er:YAG laser–activated irrigation and self-etching mode showed significantly the highest bonding strength (p < 0.001). The lengths and densities of resin tags in group PUI or group LAI with self-etching modes were longer than those in group CSI with total-etching modes. The laser-activated irrigation with self-etching modes improved the bond strength of fiber post to root dentine compared to the passive ultrasonic irrigation or conventional syringe irrigation with total or self-etching modes.

Push-Out Bond Strength of EndoSeal Mineral Trioxide Aggregate and AH Plus Sealers after Using Three Different Irrigation Protocols

OBJECTIVE

 The current study was designed to assess the bonding strength of EndoSeal MTA and AH Plus sealers after using three irrigation protocols as follows: (1) 17% Ethylenediamine tetraacetic acid, (2) 7% maleic acid, and (3) 37% phosphoric acid.

MATERIALS AND METHODS

 Push-out bond strength was evaluated for 60 middle root slices of 1-mm thickness each. They were horizontally cut from freshly extracted single-rooted human teeth. A hole in the root canal was made using a carbide round bur of 1.1 mm in diameter in a middle third root slice. Specimens were dipped in 2.5% NaOCl, and then they were grouped into three groups; G1: 17% EDTA, G2: 7% maleic acid, and G3: 37% phosphoric acid as a final irrigant for 3 minutes. Each group was subdivided into two subgroups, according to the type of sealer, either EndoSeal MTA or AH Plus.

STATISTICAL ANALYSIS

 After the full set of the sealer, the bond strength was evaluated with the push-out test by applying a force to each slice using a plunger with a 1-mm diameter. The one-way Tukey's post hoc test, analysis of variance (ANOVA) test, and Student's t-test were utilized to gather data and statistically evaluate it.

RESULTS

 The irrigation protocol used exhibited significant influence on the bond strength of EndoSeal MTA and AH Plus sealers. AH Plus sealer subgroups showed the highest bond strength with 7% maleic acid, followed by 37% phosphoric acid, and 17% EDTA. While in the EndoSeal MTA sealer subgroups, the highest bond strength was shown with the 17% EDTA followed by 7% maleic acid and 37% phosphoric acid, respectively.

CONCLUSION

 The present study revealed that the type of the final irrigant significantly impacts the bond strength of the sealer used. The AH Plus sealer bond strength was improved by using the 7% maleic acid as a final irrigant. In contrast, the EndoSeal MTA sealer showed the best results with the 17% EDTA as a final irrigant.

Can Type of Instrumentation and Activation of the Final Irrigant Improve the Obturation Quality in Oval Root Canals? A Push-Out Bond Strength Study

Simple Summary

The complete instrumentation of oval root canals remains practically unattainable. The majority of studies show that shaping oval, flat, and irregularly shaped canals is challenging, with more than half of the root canal area remaining unaltered. Furthermore, both rotary and reciprocating files compact hard tissue debris into the isthmus areas and buccal and/or lingual recesses of oval canals, impairing debridement and filling. In addition, one of the most essential variables in assessing the success of endodontic therapy is the adhesion of root canal filling material to dentin.

Abstract

To appraise the outcome of file systems and activation of the final irrigant on the push-out bond strength of root fillings in oval canals. Single-rooted mandibular premolars (n = 180) with oval canals were divided into three groups (n = 60) for instrumentation: ProTaper Next (PTN), WaveOne (WO), and Self-adjusting File (SAF). The specimens were further divided into subgroups (n = 20) and subjected to final irrigation with activation by EndoActivator or passive ultrasonic irrigation or without activation. Then, the specimens were again subdivided (n = 10) and obturated with gutta-percha and AH Plus (GP-AH) or C-Point with EndoSequence bioceramic sealer (C-EBC). One-millimeter-thick horizontal slices were cut from the apical third of the root, 5 mm from the apex, and subjected to push-out bond strength (BS) testing. Specimens for which SAF was used exhibited higher BS values than those for which PTN or WO was used (p < 0.05). Activation of the final irrigation did not affect the BS of the root fillings. Root fillings made of C-EBC presented a higher BS than those made of GP-AH (p < 0.05). Adhesive failure was more common with specimens instrumented using PTN and WO. Root canals instrumented with SAF, showed the highest bond strength values for both root filling materials. The C-EBC produced significantly higher bond strength values than those of the GP-AH.

Effect of irrigation protocols on root canal wall after post preparation: a micro-CT and microhardness study

The aim of this study was to investigate the effects of different post space irrigation protocols for removing residual filling material from dentin walls, by using microcomputed tomography (micro-CT), and the influence of these protocols on dentin microhardness. Bovine incisors (n = 35) were filled with the single-cone technique and MTA Fillapex (Angelus, Londrina, PR, Brazil). Post space preparation (PSP) was performed 7 days after filling, using the Odous Touch electrical system (Odous De Deus Ind. e Com., Belo Horizonte, MG, Brazil), followed by post space irrigation using manual irrigation, passive ultrasonic irrigation, or Easy Clean, together with 2.5% sodium hypochlorite (NaOCl), or with 2.5% NaOCl and 17% EDTA (NaOCl/EDTA). Micro-CT scans were performed at three time points. The residual filling material was evaluated at three levels: cervical, middle and apical. The Knoop test was measured with four indentations around the canal lumen at three dentin depths: X (100 μm), Y (200 μm) and Z (400 μm). Statistical analysis was performed using ANOVA (p < 0.05). The effects of the activation method (p < 0.001), and the root level (p = 0.013), as well as the interaction between the irrigant and the activation method (p = 0.041), led to different percentages of residual filling material. Lower amounts of residual filling material were observed at the cervical versus the middle and apical levels (p < 0.05). No significant differences were observed in dentin microhardness (p > 0.05). The best removal of the residual filling material was performed using the Easy Clean tip and NaOCl/EDTA, regardless of the activation methods.

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.

Evaluation of EDTA, QMix, and Irritrol solutions activated with Er,Cr:YSGG and diode lasers on the push-out bond strength of filling material

This study was conducted to evaluate the effects of ethylenediaminetetraacetic acid (EDTA), Irritrol, and QMix solutions used with manual irrigation and diode and erbium, chromium-doped yttrium, scandium, gallium, and garnet (Er,Cr:YSGG) laser activation on the bonding ability of sealer to the intraradicular dentin. The root canals of 90 mandibular incisors were instrumented, and the teeth were allocated randomly to nine groups (n = 10/group) receiving final irrigation with different irrigation solutions (EDTA, Irritrol, and QMix) and irrigant activation techniques (manual, diode laser, and Er,Cr:YSGG laser). Following endodontic filling, three sections of 1-mm thickness were obtained from the middle third of each root. The root filling was subjected to a push-out test to examine the bond strength of the sealer to dentin. The test data were examined using analysis of variance with a significance level of ɑ < .05. Failure modes were determined by stereomicroscopy, and the surface characteristics of dentin were observed by scanning electron microscopy. Irritrol showed less push-out bond strength than did the other solutions in the Er,Cr:YSGG laser groups (p < .05). In the diode laser groups, QMix provided greater adhesion than did Irritrol (p < .05). The activation of QMix with the Er,Cr:YSGG laser increased the bond strength more than did manual irrigation (p < .05). No other significant difference was observed between other comparison pairs (p > .05). QMix provided adhesion superior to that of Irritrol when activated with diode and Er,Cr:YSGG lasers. Er,Cr:YSGG laser activation increased the adhesion of filling material with QMix irrigation.

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.

Influence of Propolis, Ozone and Photodynamic therapy in root canal disinfection on resin bond strength to radicular dentin

AIM

The aim of the present study was to assess post space disinfection using different irrigants and their effect on radicular dentin bond to SERC.

MATERIALS AND METHODS

Forty single rooted mandibular 2nd premolars were collected and disinfected. All samples were decoronated maintaining root length of 12 mm and embedded vertically in acrylic resin. Shaping of the canal was performed using reciprocating system. Canals were dried using paper points and obturated with gutta percha via lateral condensation. Peso-reamers were used to create post space up to 10 mm. The post space was irrigated with 1% NaOCl before being randomly allocated into four groups (n = 10) according to different methods of canal disinfection. Samples in group 1 were subjected to photoactivated disinfection (PAD), group 2 irrigated with ethanol based propolis group 3 disinfected using ozone and group 4 irrigated with 2.25 % NaOCl with 17 % EDTA and ECL. GFP was fitted using SERC. Each sample was cut into 1 mm from coronal, middle and apical and subjected to pushout bond strength (PBS) via universal testing machine. Fracture analysis were confirmed by stereomicroscope at 40x magnification. For comparison of means, Analysis of variance (ANOVA) and Tukey multiple comparison test was used maintaining the level of significance at p <  0.05.

RESULTS

The highest PBS at all three levels were found in group 4, canal disinfected with 2.5 % NaOCl with 17 % EDTA and ECYL. Whereas, the lowest PBS was observed in group 1. Inter group comparison, prosthetic space disinfected with propolis extract showed no significant difference to group 4 canal disinfected with 2.5 % NaOCl with 17 % EDTA and ECYL at all three levels (p > 0.05). Intra group comparison in all experimental groups showed no significant difference was noted in coronal and middle thirds of group 1, group 2 and group 3 respectively (p > 0.05).

CONCLUSION

2.5 % NaOCl with EDTA and ECL treatment (group 4) remains the gold standard when used as a final canal irrigant. Propolis can be used as potential irrigant for canal disinfectant provided if the composition becomes standardized.

Influence of resin cements and root canal disinfection techniques on the adhesive bond strength of fibre reinforced composite post to radicular dentin

AIM

To determine the push out bond strength (PBS) of fibre reinforced composite post (FRCP) bonded to radicular dentin using different cement types total etch resin cement (TERC) and Self-adhesive resin cement (SARC) conditioned with (PDT, 5.25 % NaOCl with EDTA and 1% NaOCl) MATERIALS AND METHODS: Sixty freshly extracted (orthodontic purpose) human single rooted mandibular premolars were collected. Teeth were disinfected and coronal part of all samples were removed. Cleaning shaping and finishing of canal space was performed and filled with gutta percha via lateral condensation. Post space was prepared and disinfected with three irrigating solutions. Samples in group 1 and 2 disinfected 5.25 % NaOCl with EDTA, group 3 and 4 steriled with 1% NaOCl and group 5 and 6 disinfected with Methylene Blue photodynamic therapy (PDT). Based on the resin cement, FRCP was luted with TERC in group 2, 4 and 5; and with SARC in group 1,3 and 6 respectively. All specimens were subjected to aging and push-out bond strength (PBS) on universal testing machine after sectioning of each sample in three segments (coronal, middle and apical). Following push out bond strength (PBS), debonded surface were observed under stereomicroscope at 40x magnification. PBS were equated by means of analysis of variance (ANOVA) and Tukey's post hoc test maintaining level of significance (p < 0.05) RESULTS: Group 1 (SARC) and 2 (TERC) disinfected with 5.25 % NaOCl with 17 % EDTA, TERC (group 2) showed higher extrusion bond strength at all three levels coronal (9.25 ± 0.21 MPa) middle (8.81 ± 0.94 MPa) and apical (8.21 ± 0.93 MPa). Whereas, canal space sterilized with 1% NaOCl [group 3 (SARC) and group 4 (TERC)], posts cemented with TERC exhibited the higher PBS at all three levels of root canal (10.22 ± 0.36 MPa), (9.68 ± 0.51 MPa), (6.33 ± 0.08 MPa). Similarly, among PDT disinfected fiber post [group 5 (TERC) and group 6 (SARC)], TERC exhibited the greater PBS values at coronal, middle and apical levels (6.25 ± 0.39 MPa) (5.17 ± 0.22 MPa) (4.32 ± 0.69 MPa) compared to SARC specimens CONCLUSION: Irrespective of canal irrigant, fiber post bonded with TERC showed higher PBS at coronal and middle third. Fiber post bonded with SARC when irrigated with 5.25 % NaOCl with EDTA, 1% NaOCl displayed higher PBS at apical third. Canal disinfected using PDT showed lower PBS for FRCP compared to 5.25 % NaOCl with EDTA and 1% NaOCl.

The Efficiency of the Er: YAG Laser and PhotonInduced Photoacoustic Streaming (PIPS) as an Activation Method in Endodontic Irrigation: A Literature Review

In the field of endodontics, lasers have been used for a long time for the optimization of Endodontic irrigation in particular. The laser-activated irrigation (LAI) technique is based on the photomechanical effects of the lasers at low settings. They create specific cavitation phenomena and acoustic streaming in intracanal fluids. More recently, a new technique with a Er:YAG laser has been used with sub-ablative energy (20 mJ, 15 Hz) and ultra-short pulses (50 µs). This leads to intracanal cavitation and shockwaves as a result of photoacoustic and photomechanical effects. This phenomenon is called photon-induced photoacoustic streaming (PIPS). PIPS and Laser activated irrigation are described in the literature as a revolutionary and powerful method to activate the irrigant; however, systematic literature on this topic is missing. This review compares the literature on Er:YAG LAI and PIPS on endodontic irrigation with other irrigation methods. An article search was performed on the PubMed database using a series of keywords related to endodontic irrigation, including Er:YAG LAI and PIPS; 59 articles were selected for the review according to the inclusion and exclusion criteria. No in vivo study was found. The Er:YAG LAI and PIPS outperformed other methods in 33 of the 59 articles. There was a great variety in the study designs including bacterial incubation time, laser parameters, irrigation protocols, and irrigating solution used. The evidence suggests that the Er:YAG LAI and PIPS are promising in canal disinfection as well as debris and smear layer removal. However, the large variety in the study methods makes the results less significant. Further studies are needed to better evaluate the efficiency of these techniques, especially in vivo studies.

Effect of different laser-assisted irrigation activation techniques on apical debris extrusion

Objective: The aim of this study was to compare apical debris extrusion when neodymium-doped yttrium aluminium garnet (Nd:YAG) lasers, erbium-doped yttrium aluminium garnet (Er:YAG) or photon-induced photoacoustic streaming (PIPS) are used for irrigation activation.Materials and methods: A total of 60 extracted human mandibular premolar teeth have similar dimensions were included and the samples were split into four groups according to the irrigation technique (n = 15): conventional needle irrigation, PIPS, Er:YAG and Nd:YAG. ProTaper Universal system up to F4 was used for root canal instrumentation. Bidistilled water was used as an irrigation solution during instrumentation and irrigation activation. Apically extruded debris was collected into preweighed Eppendorf tubes during instrumentation and irrigation activation procedures. The tubes were then kept in an incubator at 70 °C for 5 days. The initial weight of the tube was subtracted from the final weight and the result was recorded as the weight of dry extruded debris. The data were evaluated statistically using a one-way ANOVA test followed by least significant difference post hoc test (p < .05).Results: Conventional needle irrigation caused significantly less debris extrusion than laser-assisted irrigation activation groups (p < .05). Laser-assisted irrigation activation groups caused statistically similar debris extrusion (p > .05).Conclusion: Laser-assisted irrigation activation techniques caused more debris extrusion when compared to conventional needle irrigation.

Photodynamic activation of irrigation (using different laser prototypes) on push out bond strength of fiber posts

BACKGROUND

To evaluate the influence of photodynamic therapy (PDT) and light activated irrigation (LAI) using different laser prototypes Er,Cr:YSGG (ECYL), Er:Yag (EYL), Nd-Yag (NYL) on pushout bond strength of Pre-fabricated fiber reinforced composite (PFRC) post to radicular dentin.

MATERIAL AND METHOD

Fifty maxillary and mandibular teeth were collected, cleaned and decoronated. Canals were instrumented using crown-down technique. Flaring of canals was performed using protaper S1, SX files. F1, F2 and F3 files were utilized for finishing of canal preparations. Prepared root canals were dried and obturated with gutta percha. Teeth were placed vertically within the section of polyvinyl pipes using acrylic resin. Post space preparation was completed using peso-reamers. Based on the PDT and laser activated irrigation (LAI) with different laser prototypes, samples were divided into five groups of 10 specimens each. Group 1- PDT, group 2-5.25 % NaOCl (sodium hypochlorite) and 17 % EDTA (ethylene diamine tetra acetic acid), group 3-5.25 % NaOCl with 17 % EDTA and NYL, group 4-5.25 % NaOCl with 17 % EDTA and EYL ; and group 5-5.25 % NaOCl +17 % EDTA and ECYL. Fiber post were luted in root canals with self-etch dual cure cement and teeth were sectioned at three levels (apical, middle and coronal). Push-out test was performed by placing the specimens in universal testing machine. Failure analysis of debonded surfaces was evaluated using stereomicroscope at 40× magnification. Means and standard deviations of push out bond strength were assessed by one-way analysis of variance (ANOVA). Comparison between means of push out bond strength was evaluated using Tukey multiple comparison tests (p = 0.05).

RESULT

The highest push out bond strength was observed in group 5 at all three levels, coronal (10.08 ± 0.74 MPa), middle (8.95 ± 0.94 MPa) and apical (6.00 ± 0.88 MPa). The lowest push out bond strength was demonstrated by group 2 at all levels, coronal (6.15 ± 1.22 MPa), middle (5.65 ± 0.95 MPa) and apical (2.25 ± 0.55 MPa). Intra-group comparison showed decrease in push out bond strength in the coronal to apical direction among all investigated groups. Inter-group comparison exhibited comparable push out bond strength at all three levels of root for group 1 and group 2 specimens (p > 0.05).

CONCLUSION

LAI with different laser prototypes improved push out bond values of PFRC post to root dentin as an adjunct to NaOCl and EDTA treatment. PDT improved push out strength compared to conventional canal cleaning regime.

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 830 nm Diode Laser Irradiation of Root Canal on Bond Strength of Metal and Fiber Post

OBJECTIVE AND BACKGROUND

The correct selections of the cementing agent, the endodontic post material and placement protocol are critical to provide an increased longevity of the teeth that went through endodontic treatment. The irradiation with diode laser before post cementation, can promote an antimicrobial effect. However, there is a lack of information about the effect of 830 nm diode laser on the post bond strength. This study analyzed the effect of dentin root canal irradiation with high-intensity diode laser, at 830 nm, operating in continuous or pulsed mode, on the retention of metal or fiber posts, cemented with self-etching resinous composite (Panavia F) and zinc phosphate cement (ZnPO₄).

MATERIALS AND METHODS

Human roots were irradiated with diode laser (continuous and pulsed mode). The fiber posts were luted with Panavia F and the metal posts with Panavia F or ZnPO₄ cement. Specimens were sectioned into three sections (cervical, middle, and apical). The bond strength was measured by a push-out mechanical analysis. For the statistical analysis, a three-way ANOVA test was applied following a Tukey's pairwise comparison with a significance level of p = 0.05.

RESULTS

The irradiated groups presented higher bond strength compared with nonirradiated group (p < 0.05), and the cervical and middle thirds presented higher on bond strength than the apical. The association of metal post and Panavia F presented higher bond strength when irradiated on continuous mode (p < 0.05). Fiber post and Panavia F presented higher bond strength associated to pulsed mode. The mode seems not to make a significant difference.

CONCLUSIONS

These results corroborate the importance of the post bond to dentin and root canal debris removal to increase the tooth longevity. It was shown that the dentin to post bond strength were enhanced by the diode laser irradiation either on continuous or pulsed modes.

Can intra-radicular cleaning protocols increase the retention of fiberglass posts? A systematic review

The presence of residues within the root canal after post-space preparation can influence the bond strength between resin cement and root dentin when using fiberglass posts (FGPs). Currently, there is no consensus in the literature regarding what is the best solution for the removal of debris after post-space preparation. This systematic review involved "in vitro" studies to investigate if cleaning methods of the root canal after post-space preparation can increase the retention of FGPs evaluated by the push-out test. Searches were carried out in PubMed (MEDLINE) and Scopus databases up to July2017. English language studies published from 2007 to July 2017 were selected. 475 studies were found, and 9 were included in this review. Information from the 9 studies were collected regarding the number of samples, storage method after extraction, root canal preparation, method of post-space preparation, endodontic sealer, resin cement, cleaning methods after post-space and presence of irrigant activation. Five studies presented the best results for the association of sodium hypochlorite (NaOCl) and ethylenediamine tetra-acetic acid (EDTA), while in the other 4 studies, the solutions that showed improved retention of FGPs were photon-induced photoacoustic streaming (PIPS), Qmix, Sikko and EDTA. The results showed heterogeneity in all comparisons due to a high variety of information about cleaning methods, different concentrations, application time, type of adhesive system and resin cements used. In conclusion, this review suggests that the use of NaOCl/EDTA results in the retention of FGPs and may thus be recommended as a post-space cleaning method influencing the luting procedure.

Effects of different peracetic acid formulations on post space radicular dentin

STATEMENT OF PROBLEM

The optimal irrigating solution with antimicrobial and dentin cleansing properties for post space preparation for fiber posts is unclear. Peracetic acid is one option but is available in various chemical formulations that require evaluation.

PURPOSE

The purpose of this in vitro study was to evaluate dentin surface cleanliness based on the presence of a smear layer and the number of open dentin tubules. It also investigates the chemical composition of residues after canal irrigation with a 1% peracetic acid solution (PA) at low or high concentration of hydrogen peroxide during the preparation of intracanal fiber posts.

MATERIAL AND METHODS

After filling the root canals of 40 mandibular incisors, a rotary instrument was used for intracanal preparation to place fiber posts. The teeth were divided into 4 groups (n=10) according to the post space irrigation protocol as follows: CG (control): distilled water; NA (NaOCl): 2.5% sodium hypochlorite; LH: PA with low concentration of hydrogen peroxide; and HH: PA with high concentrations of hydrogen peroxide. After irrigation, the teeth were sectioned, and the intracanal dentin surface was subjected to analysis using energy dispersive spectroscopy to evaluate chemical composition and to scanning electron microscopy (×500) to evaluate the presence of the smear layer. The number of open dentin tubules was measured by scanning electron microscopy analysis (×2000) using photo-editing software. ANOVA and the Tukey test (α=.05) were used to evaluate the data, except for the presence of a smear layer, for which the Kruskal-Wallis and Dunn tests were used (α=.05).

RESULTS

The highest concentrations of oxygen in the dentin residues were detected in LH and HH (P<.05); CG and NA showed similar oxygen concentrations (P>.05). NA had a higher concentration of chlorine (P<.05), whereas LH had a lower amount of smear layer and a larger number of open dentin tubules than the other groups (P<.05). These were equivalent to each other (P>.05), except for HH, which also had a larger number of open dentin tubules than CG and NA (P<.05).

CONCLUSIONS

PA 1% with a low concentration of hydrogen peroxide yielded a lower amount of smear layer and a larger number of open dentin tubules in the dentin of the post space when compared with PA 1% with a high concentration of hydrogen peroxide, despite maintaining a similar oxygen concentration in these dentin residues.

Laser Application to the Root Surface Increases the Bonding Strength of Surface-Treated Prefabricated Glass-Fiber Posts in Teeth with Excessive Substance Loss

BACKGROUND This study examined the effect of roughening of the root surface using an erbium-doped yttrium aluminum garnet (Er: YAG) laser on the binding strength of teeth undergoing root canal treatment. MATERIAL AND METHODS Ninety single-rooted teeth were used and assigned randomly to 9 groups (n=10 each). Root canals were prepared using the FlexMaster rotary system. An Er: YAG laser was applied to the root canals in Group 1, with no surface treatment of the glass-fiber post. In Group 2, aluminum oxide particles were applied. In Group 3, the laser was applied to the root canals, with Cojet treatment. Group 4 received laser treatment and Clearfil Ceramic Primer. In Group 5, Clearfil Ceramic Primer silane coupling was performed on post surfaces without laser treatment. In Group 6, hydrofluoric acid (HF) application was followed by Clearfil Ceramic Primer cementing of the glass post surfaces with laser application. In Group 7, HF acid treatment was performed without laser. In Group 8, the laser was applied, followed by sanding of post surfaces using Korox 50, and silane coupling with Clearfil Ceramic Primer. In Group 9, the post surfaces were sanded using Korox 50 with laser application to the root canals. The samples were subjected to a push-out experiment. The data were analyzed using Friedman's test and the Wilcoxon signed-rank test. RESULTS A significant difference in bonding strength was found among the groups (p<0.005). CONCLUSIONS Use of an Er: YAG laser in the root canal may be beneficial prior to bonding of glass posts.

Influence of Laser Activated Irrigation with two Erbium Lasers on Bond Strength of Inidividually Formed Fiber Reinforced Composite Posts to Root Canal Dentin

OBJECTIVE

The aim of this in vitro study was to investigate the effect of laser activated irrigation (LAI) using two erbium lasers on bond strength of individually formed fiber-reinforced composite (FRC) posts to root canal dentin.

MATERIALS AND METHODS

Twenty-seven single-rooted human teeth were endodontically treated and after post space preparation divided into three groups (n=9 per group), according to the pre-treatment of post space preparation: 1) Conventional syringe irrigation (CSI) and saline; 2) Er.YAG photon-induced photoacoustic streaming (PIPS) technique and saline; 3) Er,Cr:YSGG activated irrigation with RFT2 tip. Two specimens from each group were used for SEM analysis. The remaining specimens (n=7 per group) received individually formed FRC post, everStick POST, luted with self-adhesive cement, G-CEM LinkAce. After cementation, the roots were perpendicularly sectioned into 1 mm thin sections and a push-out test was carried out (0.5 mm/min). The data were calculated as megapascals and were log transformed and statistically analysed using one-way ANOVA at the level of significance set at 5%.

RESULTS

In the control group, the smear layer was still present. In the Er:YAG group, the smear layer was removed. In the Er,Cr:YSGG group, the smear layer was partially removed. The Er,Cr:YSGG group achieved the highest bond strength values, followed by the control group and then the Er:YAG group, but no statistically significant difference was found in bond strength values in the tested group of post space pretreatment (p=0.564).

CONCLUSIONS

LAI using two erbium lasers, with PIPS or RFT2 tip, did not affect the bond strength of individually formed FRC posts to root canal dentin.

Effect of Laser-Activated Irrigation on the Push-Out Bond Strength of ProRoot Mineral Trioxide Aggregate and Biodentine in Furcal Perforations

OBJECTIVE

The objective of the present study was to assess the effect of erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser-activated irrigation (LAI) of NaOCl on the push-out bond strength of furcal perforations repaired with ProRoot mineral trioxide aggregate (MTA) and Biodentine.

BACKGROUND DATA

Several studies investigated the adhesion of calcium silicate-based cements after exposure to endodontic irrigants, while effect of LAI on bond strength remains to be elucidated.

MATERIALS AND METHODS

Bur-cut furcal perforations with standard dimensions were created in 100 extracted human mandibular molars. Teeth were randomly distributed into two groups (n = 50/group) according to the repair material applied: (1) ProRoot MTA or (2) Biodentine. The specimens were further assigned into five subgroups according to the irrigation regimens used over the set materials: (a) distilled water with needle irrigation; (b) 5.25% NaOCl with needle irrigation; (c) distilled water with LAI; (d) 5.25% NaOCl with LAI; and (e) no irrigation (control). Bond strengths of the test materials were assessed by using push-out bond strength test.

RESULTS

Biodentine showed significantly higher dislocation resistance than ProRoot MTA (p < 0.05). Laser activation of 5.25% NaOCl and distilled water did not significantly affect the push-out bond strength results (p > 0.05).

CONCLUSIONS

Biodentine showed higher dislocation resistance than ProRoot MTA as a perforation repair material. Er,Cr:YSGG laser activation of irrigation aqueous solutions had no adverse effect on push-out bond strength of Biodentine and ProRoot MTA.