Effect of Carbodiimide on Bonding Durability of Adhesive-cemented Fiber Posts in Root Canals

The effect of carbodiimide on push-out bond strength of fiber posts and endogenous enzymatic activity

BACKGROUND

To investigate the effect of 0.3 M 1-ethyl-3(3-dimethylaminopropyl) carbodiimide (EDC) aqueous solution pretreatment on push-out bond strength (PBS) and matrix-metalloproteinases (MMPs) activity within radicular dentin when different post cementation strategies were employed.

METHODS

One hundred and twenty monoradicular human teeth were endodontically treated and randomly divided into six groups, depending on the cementation strategy and root dentin pretreatment (n = 20): EAR: cementation with an etch-and-rinse adhesive (LuxaBond Total Etch, DMG) and resin cement (LuxaCore Z Dual, DMG); EAR/EDC: 1 min EDC pretreatment after etching + EAR; SE: cementation with a self-etch primer (Multilink Primer, Ivoclar Vivadent) and corresponding cement (Multilink Automix, Ivoclar Vivadent); SE/EDC: self-etch primer + EDC pretreatment + SE; SA: cementation with a universal self-adhesive cement (RelyX Universal, 3 M); SA/EDC: EDC pretreatment + SA. Slices were submitted to PBS test and interfacial nanoleakage evaluation 24 h after cementation or after thermocycling (40.000 cycles, 5-55 °C). To investigate the effect of EDC on MMPs activity, 4 additional first maxillary premolars per group were processed for in situ zymography analysis. Multivariate ANOVA and post hoc Tukey tests were used to analyze PBS values. The data from in situ zymography were analyzed with Kruskal-Wallis test and Dunn's pairwise multiple comparison procedures (α = 0.05).

RESULTS

The variables "EDC pretreatment", "root region" and "thermocycling" significantly influenced PBS (p < 0.05), while the variable "cementation strategy" had no influence (p > 0.05). Thermocycling significantly reduced PBS in SE and SA groups (p < 0.05). EDC was effective in preserving PBS after artificial aging. EDC pretreatment significantly reduced enzymatic activity at baseline in EAR and SE groups, and in SA group after thermocycling (p < 0.05).

CONCLUSIONS

The use of EDC prevents the reduction of bond-strength values after artificial aging and silences endogenous enzymatic activity within radicular dentin when different cementation strategies were employed.

Effect of pretreatment with matrix metalloproteinase inhibitors on the durability of bond strength of fiber posts to radicular dentin

Objectives

Application of matrix metalloproteinases inhibitors has been suggested to improve the durability of resin–dentin bonding. The purpose of this study was to evaluate the effect of dimethyl sulfoxide (DMSO), carbodiimide (EDC), and chlorhexidine (CHX) treatment on the push‐out bond strength of fiber posts to radicular dentin.

Materials and Methods

24 extracted premolars were assigned randomly to 4 groups after root canal treatment and post space preparation (n = 6). In the first, second, and third groups, radicular dentin was treated with 1 ml of 5% DMSO, 0.3 M EDC, and 2% CHX, respectively. The fourth group (control) received no treatment. The root canals were primed with ED primer II, and the fiber posts were cemented with Panavia F2.0. In each group, half of the specimens were subjected to the push‐out test and the other half to 3000 thermal cycles before testing. Data were analyzed using two‐way analysis of variance via SPSS version 20 (p < .05).

Results

Among the nonthermocycled specimens, the values of push‐out bond strength were observed in the control, EDC, CHX, and DMSO groups, in decreasing order. Among the thermocycled specimens, the values were observed in the control, EDC, DMSO, and CHX groups in decreasing order. Thermocycling had a significant adverse effect on the push‐out bond strength (p = .015), but the effect of material (p = .375), and the interaction effect of material and thermocycling (p = .998) were not significant.

Conclusions

Application of CHX, DMSO, and EDC had no significant effect on the bond strength of fiber posts to radicular dentin.

Influence of different intraradicular chemical pretreatments on the bond strength of adhesive interface between dentine and fiber post cements: A systematic review and network meta-analysis

Systematic review and network meta-analyses were performed to answer the question: Do intraradicular chemical pretreatments affect the bond strength of the adhesive interface between dentine and fiber post cements? A literature search was performed in PubMed, Scopus, Web of Science, LILACS, BBO, and Cochrane Library in October 2018 (updated September 2021). In vitro studies that compared the bond strength assessed by push-out tests following at least two dentine chemical treatments prior to fiber post cementation were included. Risk of bias was evaluated. A random-effects Bayesian-mixed treatment comparison model was used to compare push-out bond strength of different chemical pretreatments. SUCRA (surface area under the cumulative ranking) analysis was performed to rank the pretreatments. After removing duplicates and screening titles and abstracts, 61 studies remained. SUCRA analysis showed that the best bond strength values for self-etch, etch-and-rinse, and self-adhesive cements were ethyl acetate (SUCRA: 99.8%), low concentration NaOCl (SUCRA: 83.4%), and grape seed extract (SUCRA: 97.6%), respectively. According to the SUCRA rankings, ethanol was in a good position for all adhesive strategies (SUCRA: 78.6%). The use of chemical pretreatments in intraradicular dentine of endodontically treated teeth depends on the adhesive and cementation strategy. The pretreatment generally associated with the highest bond strength was ethanol.

Comparison of the Mechanical Properties and Push-out Bond Strength of Self-adhesive and Conventional Resin Cements on Fiber Post Cementation

OBJECTIVES

The purpose of this study was to compare the mechanical properties and push-out bond strength of self-adhesive resin cements (SACs) and a conventional resin cement (CRC).

METHODS AND MATERIALS

Eighty bovine incisors were divided into four groups for cementation of a fiberglass post (Whitepost - FGM Dental Group, Coral Springs, FL) with different resin cements: three SACs (Maxcem Elite, MAX - Kerr; Calibra Universal, CAL - Dentsply; and RelyX Unicem 2, RUN - 3M Oral Care) and one CRC (RelyX Ultimate, RXU - 3M Oral Care). The groups were subdivided into two groups each (n=10) for evaluation of the push-out bond strength test (POBS) after 24 hours of water storage or after thermal aging (5000 cycles), following 24 hours of storage. The failure modes were evaluated using a stereomicroscope. Flexural strength (FS) and modulus of elasticity (EM) were determined using a three-point bending. Also, pH of the cements was measured over 48 hours and filler morphology was observed by scanning electron microscopy. Appropriate statistical analyses were performed by SPSS 21.0 (SPSS Inc., Chicago, IL, USA), with a significance level set at 5%. Results: RXU presented the highest POBS at both evaluation times. Among the SACs, RUN and CAL presented significantly lower POBS than MAX in cervical and middle-thirds at the 24-hour evaluation, and in all root regions after thermocycling. Adhesive failure between the cement and dentin were the most prevalent fractures at both times evaluated. MAX presented the lowest FS and RUN showed the highest EM. The pH reached the minimal point at the 30-minute evaluation for RXU and MAX. For RUN and CAL, the minimal pH was observed at the 60-minute evaluation. RXU and RUN presented spherical and regular filler particles, while MAX and CAL presented irregularly shaped and sized filler particles.

CONCLUSIONS

The mechanical behavior of SACs is not superior to CRC; however, among all the SACs evaluated, MAX presented the highest POBS and stability after thermocycling evaluation. MAX also reached the closest neutral pH after 48 hours. Therefore, SACs with low initial pH and strong neutralization reactions are recommended, because these characteristics may lead to better mechanical properties and stability.

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.

Need for an alternative method to cement fiber-reinforced posts - A pushout bond strength analysis

Background:

The use of dissimilar materials used as posts, luting agents, and the core often makes the restorative procedure quite complicated, as each material demands its own technical process. Furthermore, it may not necessarily result in better collective physical properties.

Aim:

The aim of this study was to analyze the pushout bond strength of a zirconia-based core buildup material in cementing two fiber posts.

Methods:

Eighty single-rooted mandibular premolars were decoronated, endodontically treated, post space prepared, and randomly assigned to one of the following four groups: carbon fiber post luted with PermaCem 2.0, carbon fiber post luted with LuxaCore Z Dual, glass fiber post luted with PermaCem 2.0, and glass fiber post luted with LuxaCore Z Dual. Pushout bond strength was evaluated in a universal testing machine for each of the 2 ± 0.5 mm sections obtained from the samples (total 160 sections)

Statistical Analysis:

One-way ANOVA and post hoc tests were used for statistical analysis.

Results:

The glass fiber posts cemented with LuxaCore Z showed significantly higher pushout bond strength (P < 0.001).

Conclusion:

LuxaCore Z Dual-core build material was more effective as a luting agent for glass fiber post cementation.

Effect of matrix metalloproteinase inhibitors on microtensile bond strength of dental composite restorations to dentin in use of an etch-and-rinse adhesive system

Aim

This study assesses the effect of matrix metalloproteinases on microtensile bond strength (μTBS) of an etch‐and‐rinse adhesive system.

Methods

This in vitro study evaluated 88 extracted premolars. The teeth were sectioned to expose dentin and were then randomly divided into four groups (n = 22). In group 1 (control), dentin surface was etched, and Adper Single Bond 2 was applied. In groups 2–4, dentin surface was etched and chlorhexidine (CHX), 1‐ethyl‐3‐(3‐dimethylaminopropyl) carbodiimide (EDC), and dimethyl sulfoxide (DMSO) were applied on the surfaces, respectively, and blotted dry. Next, Adper Single Bond 2 was applied and all teeth were built up with Z350 composite. In each group, half the samples immediately and the other half after 10,000 thermal cycles underwent μTBS test. Data were analyzed using ANOVA and Tukey's test (α = .05).

Results

In thermocycled samples, maximum μTBS was noted in CHX group followed by DMSO, EDC, and control group (p < .001). The thermocycled μTBS of composite to dentin was significantly higher in CHX group compared with EDC, DMSO, and control groups (p < .001) but was not significantly different in EDC and DMSO groups (p = .498).

Conclusion

The thermocycled μTBS obtained by the application of CHX, EDC, and DMSO was significantly higher compared with the value to the control group.

Effect of Silver Antibacterial Agents on Bond Strength of Fiber Posts to Root Dentin

This study was conducted to evaluate whether antibacterial pretreatment irrigation with silver nanoparticles (SNPs) and silver diamine fluoride (SDF) has any effect on bond strength of fiber posts cemented with three types of resin cements in root canal space. Fifty-four endodontically treated maxillary central incisor roots were prepared for fiber post (FRC Postec Plus NO.3, Ivoclar Vivadent) cementation and divided into nine groups in terms of three cement types and two pretreatments with silver antibacterial agents. The cements were as follows: an etch-and-rinse cement (ER, Excite DSC/Variolink N), a self-etch cement (SE, ED Primer/Panavia F2.0), and a self-adhesive cement (SA, Panavia SA Luting Plus). For each cement, the control group was with no treatment and two experimental groups were with SNPs and SDF treatments that were used after acid-etching for ER cement and after EDTA treatment for SE and SA cements. After fiber post cementation, each bonded root was horizontally sectioned into 1-mm thickness microslices to create two slices for each root region (apical, middle and coronal) and underwent push-out bond strength (PBS) test. Data in MPa were analyzed with two-way ANOVA and Tukey test (p=0.05). The interaction of the pretreatment type and cement type was significant (p<0.001). SNPs and SDF significantly increased PBS with ER cement (p≤0.04). This positive effect was also marginally significant for SDF with SE cement (p=0.049). For SA cement, SNPs showed a significant positive effect, but SDF had a significant adverse effect on PBS (p<0.001). The effect of pretreatment with silver antibacterial agents prior to adhesive cementation of fiber posts depends on the resin cement used. Contrary to SNPs with beneficial or no significant effect on bonding for all cements, SDF exhibited a deleterious effect with self-adhesive cement.

Effects of 1-Ethyl-3-(3-Dimethylaminopropyl) Carbodiimide on Adhesion of Posts in Teeth Obturated With Different Sealers

Abstract The aim of this study was to evaluate the effect of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) on bond strength of fiberglass posts in root canals obturated with different endodontic sealers. Seventy-eight mandibular premolars were obturated with three sealers (n=26): Endofill (END), AH Plus (AHP), and Endosequence BC Sealer (EBS). After preparation of the post space, two subgroups were formed according to the cementation of the posts (n=13): with EDC (EDC), and without EDC (control - CON). The specimens were submitted to a pull-out test, failure mode classification, and root canal surface evaluation by scanning electron microscopy after post displacement. Regarding the bond strength, a significant difference between the EDC and CON subgroups occurred only in the END (p=0.001). No difference was detected among the CON subgroups (p=0.339). However, among the EDC subgroups, AHP presented significantly higher values (END versus AHP: p=0.001; AHP versus EBS: p=0.016). Upon classification of failure modes, score 1 (≥ 50% of cement) was the most commonly observed, except for the END + EDC. Remains of endodontic sealers and resin cements were found in the cervical third, but without statistical difference (p=0.269), while in the middle third, difference occurred (p=0.004). In conclusion, EDC decreases bond strength when associated with END sealer, without changing the failure mode between the resin cement and fiberglass post. The best performance was observed when EDC was combined with AHP sealer.

Effect of silver diamine fluoride on the bond durability of normal and carious dentin

Background

Silver diamine fluoride (SDF) has attracted attention because of its clinical success in arresting dentin caries. It has been shown that it can inhibit matrix metalloproteinases and cysteine cathepsins. These two properties might be beneficial in bonding to caries-affected dentin (CAD). Therefore, the present study aimed to investigate the effect of SDF on the durability and bond strength to the CAD.

Material and Methods

Forty-eight third molars with occlusal caries were used. The roots were cut, and the occlusal enamel was removed. The CAD area surrounded by the normal dentin (ND) was exposed. All the specimens were bonded with an etch-and-rinse adhesive, but half of them were treated with SDF after acid etching (NT or SDF). Two cylinders of composite (0.9 mm in diameter and 0.7 mm in height) were built-up on each specimen, one on the CAD and the other on the ND area. The specimens in each group (NT-ND, NT, CAD, SDF-ND, SDF-CAD) (n=24) were equally divided into two subgroups. One subgroup was tested for microshear bond strength 24 hours after bonding (T0), and the other subgroup was tested after six months of water storage (T6). The bond strength data were analyzed using three-way ANOVA. Subgroup analysis was performed using independent samples t-test. Fracture patterns were also evaluated.

Results

At T0, the bond strength of NT-ND was higher than that of NT-CAD (p<0.00), but the bond strength of SDF-ND and SDF-CAD were not different (p=0.77). Comparison of the bond strength of the groups between the two time intervals yielded the following results: NT-ND-T0> NT-ND-T6 (p=0.04), SDF-ND-T0=SDF-ND-T6 (p=0.39), NT-CAD-T0=NT-CAD-T6 (p=0.51) and SDF-CAD-T0>SDF-CAD-T6 (p<0.00).

Conclusions

The SDF treatment increased the bond strength to CAD but did not affect the bond strength to the ND. SDF hindered the decrease in the bond strength to the ND caused by aging. However, the effect of SDF on increasing the bond strength to CAD disappeared after aging. Key words:Silver diamine fluoride, caries-affected dentin, bond strength.

The effect of silver nanoparticles, zinc oxide nanoparticles, and titanium dioxide nanoparticles on the push-out bond strength of fiber posts

Background

This study was undertaken to investigate the effect of intraradicular dentin pretreatment with silver nanoparticles (SNPs), zinc oxide nanoparticles (ZNPs), and titanium oxide nanoparticles (TNPs) on the push-out bond strength (PBS) of fiber posts to root dentin using two types of resin cements.

Material and Methods

Eighty single-rooted human premolar roots were randomly divided into eight groups after endodontic treatment and post space preparation, according to the type of intraradicular dentin pretreatment with different nanoparticle solutions (n=20). The groups included no pretreatment (control) and pretreatments with SNPs, ZNPs, and TNPs. Each group was divided into 2 subgroups (n=10) according to cementation: Excite DSC/Variolink II and ED Primer II/Panavia F2.0. The PBS values were measured in different areas of the post space. The data were subjected to the three-way analysis of variance and Tukey tests (p=0.05).

Results

The SNP-pretreated groups showed significantly higher PBS values than the other groups. No significant differences in PBS were noted among the control, ZNP-pretreated, and TNP-pretreated groups. There was no significant difference in the PBS of the fiber posts with respect to cement type. The PBS was significantly lower in the apical region than in the other two regions. There was no statistically significant difference between the PBSs of the cervical and middle thirds.

Conclusions

Intraradicular dentin pretreatment with SNPs, TNPs, and ZNPs did not interfere with the PBS of the fiber posts. The best result was obtained for the SNP-pretreated groups for both types of cement. Also, the lowest PBS was found in the apical third of the root canal spaces.

Key words:Fiber post, nanoparticles, push-out bond strength.

Effect of carbodiimide and chlorhexidine on the bond strength longevity of resin cement to root dentine after radiation therapy

AIM

To evaluate the effect of carbodiimide (EDC) and chlorhexidine (CHX) on the bond strength (BS) of resin cement to root dentine of teeth submitted to radiotherapy.

METHODOLOGY

One hundred and twenty extracted maxillary canines were selected and assigned to 2 groups (n = 60): nonirradiated and irradiated (30 cycles of 2 Gy, total 60 Gy). Roots lengths were standardized, and canals were prepared and filled. Post spaces were then prepared, and the samples were redistributed according to dentine treatment (n = 20): saline solution (SF); CHX 2%; or EDC 0.5M. After drying the post space, fibreglass posts were cemented. Cross-sectioned slices were obtained, and in half of the specimens of each subgroup (n = 10), the analysis was performed immediately; the others (n = 10) were stored for 10 months before analyses. The most cervical slice of each third was subjected to a push-out test and failure pattern analysis (n = 10), and the most apical slice submitted to the analysis of the adhesive interface by SEM (n = 5). The bond strength data were submitted to anova and Tukey tests, the adhesive interface adaptation was submitted to Kruskal-Wallis and Dunn's tests, and the Chi-square test was used to evaluate the type of failure.

RESULTS

The irradiated specimens had significantly lower bond strength (13.8 ± 4.3) than the nonirradiated (18.1 ± 3.1; P < 0.001). For the irradiated teeth, the bond strengths were significantly lower in the SF and CHX groups (P < 0.001). Also, the bond strengths reduced significantly after 10 months in the SF and CHX groups (P < 0.001). Cohesive failures occurred in dentine for irradiated specimens. Poorer interface adaptation, dentine fractures and microfractures were observed in irradiated specimens, and better adaptation was observed for specimens after EDC treatment.

CONCLUSIONS

Radiotherapy was associated with lower bond strength and worse interface adaptation. Dentine treatment with EDC contributed to adhesive interface longevity during the cementation of glass fibre posts in nonirradiated and irradiated teeth.

Longevity of bond strength of resin cements to root dentine after radiation therapy

AIM

To evaluate the bond strength and adhesive interface between several resin cements and root dentine immediately and 6 months after radiotherapy.

METHODOLOGY

Sixty maxillary canines were selected and randomly assigned to two groups (n = 30): one group was not irradiated and the other one was subjected to a cumulative radiation dose of 60 Gy. The teeth were sectioned to obtain roots 16 mm long and the canals were prepared with the Reciproc system (R50) and filled using a lateral condensation technique with an epoxy resin sealer. Each group was divided into three subgroups (n = 10) according to the resin cement used for fibreglass fibre post cementation: RelyX-U200, Panavia-F2.0 and RelyX ARC. The posts were cemented in accordance with the manufacturer's recommendations. Three 1-mm-thick dentine slices were then obtained from each root third. The first two slices in the crown-apex direction of each third were selected for the push-out test. The failure mode after debonding was determined with a stereo microscope. The third slice from each root third was selected for scanning electron microscopy (SEM) analyses to examine the resin cement-dentine interface with 100, 1000, 2000 and 4000× magnification. Bond strength data were analysed by anova and Tukey's test (α = 0.05).

RESULTS

Significantly lower bond strength (P < 0.0001) was obtained after irradiation compared to nonirradiated teeth. RelyX-U200 cemented fibre posts had the higher bond strength (15.17 ± 5.89) compared with RelyX ARC (P < 0.001) and Panavia-F2.0 (P < 0.001). The evaluation after 6 months revealed lower bond strength values compared to the immediate values (P < 0.001) for irradiated and nonirradiated teeth. Cohesive failures occurred in the irradiated dentine. SEM revealed fractures, microfractures and fewer collagen fibres in irradiated root dentine. RelyX-U200 and Panavia-F2.0 were associated with a juxtaposed interface of the cement with the radicular dentine in irradiated and nonirradiated teeth, and for RelyX ARC, hybrid layer formation and tags were observed in both irradiated and nonirradiated teeth.

CONCLUSION

Radiation was associated with a decrease in the push-out bond strength and with lower resin cement/root dentine interface adaptation. Self-adhesive resin cement was a better alternative for fibre post cementation in teeth subjected to radiation therapy. The bond strength decreased after 6 months.

Adhesion performance of a universal adhesive in the root canal: Effect of etch-and-rinse vs. self-etch mode

PURPOSE

Universal adhesives are new systems that can be used in etch-and-rinse (ER) and self-etch (SE) modes. This in vitro study evaluated the bonding performance of a universal adhesive in ER mode and SE mode with two irrigants for luting fiber posts in the root canal.

MATERIALS AND METHODS

After separation of the roots from the crowns of 56 maxillary central incisors and endodontic treatment, 10-mm post space was prepared. The roots were divided into seven groups according to irrigant/adhesive protocol used for cementation of posts: 1) sodium hypochlorite (NaOCl) irrigant + acid etching + One-Step Plus, 2) NaOCl + Clearfil SE Bond (CSE) and 3) EDTA + CSE as controls; 4) NaOCl + All-Bond Universal (AB) in ER mode, 5) NaOCl + AB in SE mode, 6) EDTA + AB in SE mode, 7) distilled water + AB in SE mode. Posts were luted using Duo-link. The bonded roots were sectioned into microslices. After push-out bond strength (PBS) testing, data in MPa were analyzed with two-way ANOVA and Tukey test (α = 0.05).

RESULTS

PBS was significantly affected by irrigation/adhesive protocol and root region (P<0.05), with no significant interaction of these factors. PBS of ABU in ER mode with NaOCl and in SE mode with NaOCl or EDTA was comparable to that in the respective controls. The highest and lowest PBSs were recorded for ABU in the SE mode with EDTA (15.38 ± 4) and NaOCl (10.17 ± 3.5), respectively. PBS of AB in ER and SE modes was similar when distilled water was used in the SE mode.

CONCLUSION

Adhesive performance of AB in the ER mode was comparable to or different from the SE mode, depending on the irrigant used to prepare post space in SE approach. AB could behave as a reliable bonding for post cementation.

Dual function of proanthocyanidins as both MMP inhibitor and crosslinker in dentin biomodification: A literature review

Proanthocyanidin, a natural phytochemical bioactive agent, simultaneously can silence the activity of dentinal proteases and crosslink the collagen matrix; both of these phenomena would be the fundamentals for bio-stability of resin-dentin interface which is essential for a promising adhesive dentistry. This review provides an overview of the data developed by different groups of researchers and highlighted topics are proanthocyanidin chemistry, natural resources and the unique interactions between proanthocyanidincollagen and proanthocyanidin-MMPs in dentin. Besides, clinical applications of proanthocyanidin in the form of proanthocyanidin-containing adhesives, preconditioners and etchants have been reviewed. One hundred and twelve studies have been published in peer-reviewed journals from 1981 to 2017, all were comprised in this review, some of them have been actually proven to be promising from clinical point of view and others need further assessment before their adoption as clinically practicable protocols.

Effects of Collagen Crosslinkers on Dentine: A Literature Review

This aim of this review is to explore the current research related to crosslinking agents used on dentine. A systematic search of publications in PubMed and Web of Science databases was performed. Further retrieval was conducted using the search terms of specific names of crosslinkers. Reviews, conference abstracts, dissertation and theses, non-English articles, studies of intrinsic crosslinking of dentine, studies of adhesives without specific crosslinker components, studies of crosslinker applications in other collagenous tissues or tooth-like structures and irrelevant studies were excluded. Manual screening was conducted on the bibliographies of remaining papers to identify other relevant articles. One hundred and one articles were included in this systematic review and full texts were retrieved. Both synthetic and naturally derived crosslinkers have been found to exhibit significant effects in biomodification of dentine via their multiple interactions with the dentine matrix. A stable matrix network or a durable hybrid layer in dentine bonding could be achieved, where the dentine collagen fibrils show improved biochemical and biomechanical properties and enzymatic biodegradation is reduced. Although no crosslinkers have been tested in clinical trials, extensive research has been conducted in laboratory studies to investigate their potential applicability for inhibition of demineralisation and/or promotion of remineralisation, caries prevention as well as improvement of bonding performance of adhesive systems. Further studies are needed to develop the feasibility for clinical use, reduce side effects as well as explore mechanisms of action and long-term effectiveness.

The effect of two cross-linking agents on dentin bond strength of resin-modified glass ionomer

Objectives:

The hybrid layer at the interface of resin-modified glass ionomer cements and dentin is prone to degradation by endogenous matrix metalloproteinases. We aimed to investigate the effect of two types of collagen crosslinkers, carbodiimide and proanthocyanidin (PA), on immediate and medium-term bond strength of a resin-modified glass ionomer to dentin.

Materials and Methods:

Seventy-two molars were flattened on the occlusal surface to expose dentin. The specimens were divided into control, 1-ethyl-3-(3-dimethylaminopropy) carbodiimide hydrochloride (EDC), and PA groups (n = 24). In the EDC and PA groups, carbodiimide and PA solutions were applied for 1 min, respectively. Resin-modified glass ionomer was bonded. Half of the specimens in each group were tested for shear bond strength after 24 h and the other half were tested after 6 months.

Statistical Analysis:

Data were analyzed with SPSS version 16 (SPSS Inc, Chicago, IL, USA), using two-way ANOVA, and subgroup analysis was performed using one-way ANOVA, Tukey's test, and t-test.

Results:

Two-way ANOVA showed that treatment and time affected the bond strength. Carbodiimide and PA did not affect the immediate bond strength (P = 0.51). After 6 months, the bond strength of the EDC group was significantly lower than that of the control and PA groups. Bond strength of the control and PA groups increased after 6 months (P ≤ 0.002).

Conclusion:

PA did not interfere with maturation of RMGIC unlike carbodiimide. Therefore, it can be suggested as an matrix metalloproteinase inhibitor before bonding of resin-modified glass ionomer to dentin.

Effect of crosslinkers on bond strength stability of fiber posts to root canal dentin and in situ proteolytic activity

STATEMENT OF PROBLEM

Improved stability of the adhesive interface can be obtained using crosslinkers. However, research on the use of crosslinkers in root dentin is lacking.

PURPOSE

The purpose of this in vitro study was to evaluate the effect of crosslinkers on the proteolytic activity of root dentin and on the bond strength of resin-cemented fiber posts.

MATERIAL AND METHODS

Single root canals were obtained from premolars (n=48) and endodontically treated before being divided into 4 groups: deionized water (control), 0.5 mol/L carbodiimide, 5% proanthocyanidin, or 5% glutaraldehyde. After removing the canal sealer, the dentin was etched with phosphoric acid, followed by water rinsing and the application of the crosslinkers for 60 seconds. Fiber posts were cemented using an adhesive (Single Bond 2) and resin cement (RelyX ARC). The roots were then transversally sectioned to obtain 1 mm thick specimens from the cervical, middle, and apical thirds and then aged for 24 hours or 9 months. Nine roots per group were used for the push-out test and 3 for determining the proteolytic activity of the root dentin by in situ zymography. Bond strength data were submitted to a mixed-model ANOVA and Bonferroni tests (α=.05).

RESULTS

Only proanthocyanidin negatively affected the 24-hour bond strength. After 9 months, a significant decrease in bond strength was seen for all groups, except for the crosslinked treated specimens from the cervical third of the root canal. Intense gelatinolytic activity was detected in the control group after 24 hours but was inhibited in the crosslinker-treated groups. Proteolytic activity was also not detected after 9 months for the groups treated with the crosslinkers, irrespective of the root canal third. Conversely, proteolytic activity increased for the specimens from the control group.

CONCLUSIONS

Although no proteolytic activity was detected in the hybrid layers along the entire root canal, dentin biomodification with crosslinkers was effective in preventing bond strength loss only in the cervical third.

Effect of antibacterial/adhesive approaches on bonding durability of fiber posts cemented with self-etch resin cement

BACKGROUND

Longevity of post-retained restoration is highly depended on bonding stability of fiber post (FP) to root dentin. This study evaluated the effect of different antibacterial/adhesive approaches on bonding durability of FPs luted into root canal with a self-etch cement.

MATERIAL AND METHODS

Seventy-two human maxillary central incisor roots were divided into six groups after endodontic treatment, based on the antibacterial/adhesive treatments as follows: 1)ED primer II (ED, control); 2) Clearfil Protect Bond (PB); 3) 2% chlorhexidine (CH) pretreatment + ED primer II (CH+ED); 4) CH-incorporated into ED primer II (CH in ED); 5) CH pretreatment + Clearfil SE Bond (CH+SE); and 6)CH-incorporated into SE primer (CH in SE). The FPs were then cemented using PanaviaF2.0. After micro-slicing the bonded root dentin, a push-out bond strength (PBS) test was performed immediately or after two years of water storage. Data were analyzed using ANOVA and post hoc Tukey tests (α=0.05).

RESULTS

The effects of antibacterial/adhesive approach, time and interaction between the main factors were significant (p=0.01). There was no significant difference between the immediate groups, except between the CH+ED group (the lowest PBS) and PB and CH in SE groups (the highest PBS) (p≤0.03). After aging, the same difference was observed (p≤0.02); the control group exhibited a significantly lower PBS compared to the other groups (p≤0.01), except for CH+ED. Aging significantly decreased PBS of all the groups (p≤0.01); the control group exhibited the highest reduction.

CONCLUSIONS

CH incorporated into self-etch primers or in pretreatment step prior to two-step self-etch adhesive and antibacterial adhesive could improve bond stability of self-etch cemented fiber post. However, none of these was capable of inhibiting bond degradation over time. Key words:Push-out bond strength, Fiber post, Chlorhexidine.

Effect of dimethyl sulfoxide on bond durability of fiber posts cemented with etch-and-rinse adhesives

PURPOSE

This study was undertaken to investigate whether use of an adhesive penetration enhancer, dimethyl sulfoxide (DMSO), improves bond stability of fiber posts to root dentin using two two-step etch-and-rinse resin cements.

MATERIALS AND METHODS

Forty human maxillary central incisor roots were randomly divided into 4 groups after endodontic treatment and post space preparation, based on the fiber post/cement used with and without DMSO pretreatment. Acid-etched root dentin was treated with 5% DMSO aqueous solution for 60 seconds or with distilled water (control) prior to the application of Excite DSC/Variolink II or One-Step Plus/Duo-link for post cementation. After micro-slicing the bonded root dentin, push-out bond strength (P-OBS) test was performed immediately or after 1-year of water storage in each group. Data were analyzed using three-way ANOVA and Student's t-test (α=.05).

RESULTS

A significant effect of time, DMSO treatment, and treatment × time interaction were observed (P<.001). DMSO did not affect immediate bonding of the two cements. Aging significantly reduced P-OBS in control groups (P<.001), while in DMSO-treated groups, no difference in P-OBS was observed after aging (P>.05).

CONCLUSION

DMSO-wet bonding might be a beneficial method in preserving the stability of resin-dentin bond strength over time when fiber post is cemented with the tested etch-and-rinse adhesive cements.