Do chlorhexidine and ethanol improve bond strength and durability of adhesion of fiber posts inside the root canal?

Glycolic acid on push-out bond strength of fiber post and smear removal: an in vitro study

This study aims to investigate glycolic acid (GA) as a final irrigant on push-out bond strength of fiber post and smear removal. Ninety mandibular premolars were stabilized with a silicone key and photographed, and canal cross-section was calculated by image processing software. Round canal morphology was selected. The specimens were divided into five groups (n = 18); 10%GA, 17%EDTA, NaOCl + 10%GA, NaOCl + 17%EDTA, and the control. Fifteen specimens were used for the push-out. Three specimens were evaluated using a scanning electron microscope after post space preparation. Two-way ANOVA and Chi-square were used for statistics. GA presented higher strength than EDTA (p < 0.05). The NaOCl + GA showed higher strength than the NaOCl + EDTA (p < 0.05). The highest values were observed in cervical and lowest in apical thirds (p < 0.05). The most failure type was between dentin and resin (p < 0.05). GA removed the smear in the post space including the apical third. The NaOCl + GA has superiority to NaOCl + EDTA on push-out strength. Glycolic acid improved the bond strength of fiber post when used as a final post space irrigant. The combination of NaOCl and glycolic acid did not negatively affect the bond strength and was more effective compared to the combination with EDTA. Glycolic acid improved the bond strength of fiber post when used as a final post space irrigant. The combination of NaOCl and glycolic acid did not negatively affect the bond strength and was more effective compared to the combination with EDTA.

Effects of Etching Time and Ethanol Wet Bonding on Bond Strength and Metalloproteinase Activity in Radicular Dentin

(1) Background: The objective of this in vitro study was to evaluate the impact of different etching times and ethanol pre-treatments on the immediate bond strength of a hydrophilic multi-mode universal adhesive (Clearfil Universal Bond Quick, Kuraray, UBQ) and on the consequent gelatinolytic activity of metalloproteinases (MMPs) on radicular dentin. (2) Methods: Sixty single-root teeth were selected and divided into four groups according to the adhesive protocol applied for fiber post cementation: (G1) 15 s H3PO4 application + UBQ; (G2) 30 s H3PO4 application + UBQ; (G3) 15 s H3PO4 application + ethanol pre-treatment + UBQ; (G4) 30 s H3PO4 + ethanol pre-treatment + UBQ. After adhesive procedures, fiber posts were luted into the post space with a dual-curing cement (DC Core, Kuraray) and light-cured for 40 s. To perform the push-out test and nanoleakage analyses for both coronal end apical areas, 1 mm slices were prepared, following a 24 h storage period in artificial saliva. Additionally, an in situ zymographic assay was conducted to explore endogenous MMP activity within the radicular layer. Results were statistically analyzed with ANOVA and Tukey post hoc tests. Statistical significance was set at p < 0.05. (3) Result: ANOVA revealed a statistically significant difference in push-out bond strength related to the pre-treatment variable but did not highlight any significance of etching time. Specimens pre-treated with ethanol wet bond application showed higher bond strength (p < 0.01). In situ zymography quantification analyses revealed that all tested groups, independently of etching time end ethanol pre-treatment, activated MMP gelatinolytic activity. A significant increase in MMP activity was detected for the 30 s etching time. However, ETOH pre-treatment significantly reduced MMP activity within the adhesive interface (p < 0.01). (4) Conclusions: The tested adhesive showed similar results regardless of the etching time protocol. The gelatinolytic activity of MMPs was observed in all the groups. Further investigations and extended follow-ups are required to validate the results of the present study in vivo.

Analysis of the adhesive interface of dentine treated with carbodiimide and chitosan before cementation of fiberglass posts with different resin cements

The objective of this study is to evaluate the effect of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) and chitosan (CHI) on the adhesive interface of resin cements to root dentine. Forty-five upper canines were sectioned, endodontically treated, prepared and divided into three groups according to dentine treatment (distilled water-DW, CHI 0.2% and EDC 0.5) and in three subgroups according to resin cement: RelyX ARC, Panavia F 2.0 or RelyX U200. Slices were obtained, with five slices of each third submitted to the analysis of the adaptation of the adhesive interface through scores and the perimeter with gaps in confocal laser scanning microscopy and one slice of each third later evaluated qualitatively in scanning electron microscopy. The results were analyzed using with Kruskal-Wallis and Spearman correlation tests. There was no difference in adaptation for the different resin cements (p = .438). EDC presented better adaptation when compared to the groups treated with DW and CHI (p < .001), while the CHI and DW presented similar adaptation values (p = .365). No difference was observed in the perimeter referring to the gap areas for the different resin cements (p = .510). EDC showed a lower percentage of perimeters with gaps when compared to CHI (p < .001), with the percentage of perimeter with gaps of teeth treated with CHI being lower than DW (p < .001). A positive correlation coefficient equal to 0.763 was obtained between the perimeter with gaps and the adaptation data of the adhesive interface (p < .001). EDC resulted in better adaptation of the adhesive interface and a lower percentage of perimeters with gaps compared to chitosan.

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.

Push-out Bond Strength of Two Fiber Posts in Composite Resin Using Different Types of Silanization

OBJECTIVES

The aim of this study was to evaluate the effect of different surface treatments and thermocycling (TC) on the push-out bond strength of two brands of glass fiber posts (GFPs) to composite resin.

METHODS

White Post DC (WP) (FGM Dental Group International, Joinville, Santa Catarina, BR) and Exacto (EC) (Angelus, Clinical Research Dental, Londrina, PR, Brazil). GFPs were cleaned with 70% alcohol and divided into five groups, according to the surface treatment (n=15): control (C), without treatment; prehydrolyzed silane (S-pre) (Prosil, FGM Dental Group International); 37% phosphoric acid + prehydrolyzed silane AcS-pre); Scotchbond Universal Adhesive System (AdU), 3M Oral Care; two-bottle silane (S2B) (Dentsply Sirona Inc). The composite resin was inserted around the posts by using a split matrix. The samples were cut into 1-mm slices. Half of the samples were subjected to the push-out test immediately, and the other half underwent TC before the test. After failure analysis, the data were submitted to three-way analysis of variance (ANOVA) (α=0.05).

RESULTS

EC achieved higher bond strength than WP, regardless of TC (p<0.05). Regarding WP, surface treatments (p<0.001) and TC (p<0.001) influenced bonding strength. As for EC without TC, the highest bond strength (p<0.05) was found for C, then AcSpre, S-pre, AdU, and S2B. Application of TC resulted in a statistically higher bond strength values for the EC AcS-pre group (p<0.05), followed by S2B, S-pre, C, and AdU. The WP failures were predominantly cohesive, similar to the EC AdU and EC S2B groups. The other EC groups showed mostly mixed failures.

CONCLUSIONS

Surface treatment and TC affected the bond strength to composite resin, depending on which post was used. It is important for dentists to understand the effects of different types of silanization on their chosen post.

Influence of restorative material and cement on the stress distribution of endocrowns: 3D finite element analysis

Purpose

This study aimed to evaluate the influence of different types of restorative materials and resin cements on the stress distribution in the regions of the restoration, cement layer and dental remnant in endodontically treated posterior endocrowns.

Methods

A 3D finite element analysis (FEA) model of the first mandibular molar that was restored with an endocrown designed by computer-aided design (CAD) software was generated. Three kinds of restorative materials (Vita Enamic (VE), IPS e.max CAD (EMX) and Grandio blocs (GR)) and two types of cementing materials (NX3 and Maxcem Elite Chroma (MX)) were analysed with such a model. The food layer was also designed before vertical (600 N) forces were applied to simulate physiological masticatory conditions. Thermal expansion was used to simulate the polymerization shrinkage effects of cement layers. The results were obtained by colorimetric graphs of the maximum principal stress in the restoration and tooth remnant. The failure risk of the cement layer was also calculated based on the normal stress.

Results

The elastic modulus was positively correlated with the tensile stress peak values in the restoration, mainly at the intaglio surface. However, in the cervical enamel and cement layer, restorative material with a higher elastic modulus generated lower peak stress values. The cement with a higher elastic modulus resulted in higher stress peak values inside the cement layer. The combination of EMX (restorative material) and NX3 (cement material) in the cement layer resulted in the lowest failure risk.

Significance

The ceramic material EMX with a higher elastic modulus appeared to be more effective at protecting the cement layer and residual enamel tissue. Based on the analysis of the failure risk of the cement layer, the combination of EMX and NX3 was recommended as an optional material for endocrowns for endodontically treated posterior teeth.

Root canal pre-treatment and adhesive system affect bond strength durability of fiber posts ex vivo

OBJECTIVES

To investigate the effect of different pre-treatments on the long-term bond strength of fiberglass posts luted either with dual-curing self-etch adhesives and core build-up composites or with a self-adhesive resin (SAR) cement.

MATERIALS AND METHODS

In total, 180 human root-filled teeth received post-space preparations and three different dentin pre-treatments (PTs): PT1, ethanol (99%); PT2, ethanol-tertiary-butanol-water-solution (AH Plus Cleaner, Dentsply Sirona; York, USA); and PT3, distilled water (control). Five luting systems were used: FU, Futurabond U (Voco; Cuxhaven, Germany); CL, Clearfil DC Bond (Kuraray Noritake; Okayama, Japan); GR, Gradia Core SE Bond (GC Europe NV; Leuven, Belgium); LU, LuxaBond Universal (DMG; Hamburg, Germany); and RX, RelyX Unicem 2 (3M; Minnesota, USA). Roots were cut into six slices (1 mm thick). From each root canal region, three slices were submitted to immediate and three to post-storage push-out testing. The latter were subjected to thermocycling (5-55°C, 6.000 cycles) and stored for six months in saline solution (0.9%, 37°C). Data were analysed using repeated measures ANOVA and chi-square tests (MV±SD).

RESULTS

Bond strength was significantly affected by material (p<0.0005), pre-treatment (p=0.016), and storage (p<0.0005; repeated-measures ANOVA). LU (18.8±8.1MPa) revealed significantly higher bond strength than RX (16.08±6.4MPa), GR (15.1±4.6MPa), CL (13.95±5.2MPa), and FU (13.7±6.3MPa). PT1 (16.5±6.9MPa) revealed significantly higher bond strength than PT3 (14.5±5.7MPa).

CONCLUSIONS

A universal adhesive in self-etch mode combined with a core build-up material revealed higher bond strength than a SAR cement, both interacted positively with Ethanol pre-treatment.

CLINICAL RELEVANCE STATEMENT

Ethanol (99%) rinsing can be recommended as part of post and core pre-treatment for the investigated luting systems.

Effect of epigallocatechin-3-gallate and thermal cycling on the bond strength of resin cements to the root dentin

This study evaluated the effect of epigallocatechin-3-gallate (EGCG) solution and thermal cycling on the bond strength (BS) of fiber posts to the root dentin using two different resin cements (conventional or self-adhesive). One hundred and forty-four bovine roots were endodontically treated. After post space preparation, specimens were randomly divided into six groups (n = 24) according to dentin pretreatment [distilled water, 0.05% EGCG solution or 2% chlorhexidine (CHX) solution] and resin luting agent used for fiber post cementation (RelyX ARC or RelyX U200-3 M ESPE). Then, the samples were separated into two subgroups (n = 12): storage in distilled water at 37 °C for 24 h and thermal cycling (5 °C/55 °C, dwell time 30 s-12,000 cycles) during 6 months. After that, the specimens were subjected to the pull-out BS test (Universal Testing Machine-0.5 mm/min) and the failures pattern was analyzed in a stereomicroscope. According to the BS results (three-way ANOVA, Tukey's test, α = 0.05), the highest values were reported in the group EGCG + RelyX U200, showing significant statistical differences compared to all the other experimental groups. For Control and CHX groups BS values, there was no significant difference (p > .05) between the resin cements. For conventional resin cement, there was no significant difference among treatment solutions (p > .05). The thermal cycling did not influence the BS results (p > .05). As reported by the failure mode analysis, adhesive failure was predominant in all groups. EGCG solution improved the bond strength of self-adhesive resin cement to root dentin.

The restoration of root filled teeth: a review of the clinical literature

Clinicians often face dilemmas regarding the most appropriate way to restore a tooth following root canal treatment. Whilst there is established consensus on the importance of the ferrule effect on the predictable restoration of root filled teeth, other factors, such as residual tooth volume, tooth location, number of proximal contacts, timing of the definitive restoration and the presence of cracks, have been reported to influence restoration and tooth survival. The continued evolution of dental materials and techniques, combined with a trend towards more conservative endodontic-restorative procedures, prompts re-evaluation of the scientific literature. The aim of this literature review was to provide an updated overview of the existing clinical literature relating to the restoration of root filled teeth. An electronic literature search of the PubMed, Ovid (via EMBASE) and MEDLINE (via EMBASE) databases up to July 2020 was performed to identify articles that related the survival of root filled teeth and/or restoration type. The following and other terms were searched: restoration, crown, onlay, root canal, root filled, post, clinical, survival, success. Wherever possible, only clinical studies were selected for the literature review. Full texts of the identified articles were independently screened by two reviewers according to pre-defined criteria. This review identifies the main clinical factors influencing the survival of teeth and restorations following root canal treatment in vivo and discusses the data related to specific restoration type on clinical survival.

Effect of ethanol-wet bonding on porosity and retention of fiberglass post to root dentin

This in vitro study aimed to assess the effects of different pretreatments used to adapt glass-fiber posts cemented to root canals with different resin cements, regarding porosity percentage and bond strength. Twelve bovine incisor roots were prepared with Largo drills. After post space preparation, the specimens were randomized into two types of pretreatment groups (n = 3): water-wet bonding and ethanol-wet bonding. After the post were cemented, the roots were stored in 100% humidity at room temperature for 7 days. The samples were scanned by microcomputed tomography (micro-CT). Images were reconstructed by NRecon software, and CTAn software was used to analyze the porosity percentage (%) at the luting interface. Evaluation of the push-out bond strength was performed by serially cutting the roots, and submitting the slices to testing. Additionally, the resin cement post-gel shrinkage values (%) were measured using the strain-gauge method (n = 10). Data were analyzed by two-way ANOVA, Tukey's test and Student's t test (a = 0.05). The roots prepared with ethanol-wet bonding using RelyX™ U200 had significantly lower porosity in the coronal and apical thirds (p < 0.05). The group prepared with ethanol-wet bonding using RelyX™ ARC presented better bond strength results in the coronal and apical thirds (p < 0.05). RelyX™ ARC (0.97%) produced a higher post-gel shrinkage value than RelyX™ U200 (0.77%). Canals pretreated with ethanol-wet bonding presented better outcomes in regard to porosity percentage and push-out bond strength.

Effect of fiber post space irrigation with different peracetic acid formulations on the bond strength and penetration into the dentinal tubules of self-etching resin cement

STATEMENT OF PROBLEM

The post space must be irrigated with solutions that do not interfere with the bond strength and enhance penetration into the dentinal tubules of self-etching resin cement. Which solution is best is unclear. Peracetic acid with different formulations appears to be a good option.

PURPOSE

The purpose of this in vitro study was to evaluate the effect of irrigating the fiber post space by using 1% peracetic acid (PA) at low (LH) or high (HH) hydrogen peroxide concentration on the bond strength and penetration into the dentinal tubules of RelyX U200 self-etching resin cement.

MATERIAL AND METHODS

After intraroot preparation for fiber posts in 60 endodontically treated teeth, the specimens were divided into 4 groups (n=15) according to the irrigation protocol: CG (control), distilled water; NA (NaOCl), 2.5% sodium hypochlorite; LHPA, PA with a low concentration of hydrogen peroxide; and HHPA, PA with a high concentration of hydrogen peroxide. The fiber posts were then cemented with self-etching resin cement labeled with rhodamine. Cross sections of the thirds were obtained by confocal scanning microscopy and submitted to the push-out and cement penetration tests. The data obtained in the push-out tests were evaluated by using ANOVA and the Tukey post hoc test, and those data obtained in the confocal screening were evaluated by using the Kruskal-Wallis and Dunn (Bonferroni correction) tests (α=.05).

RESULTS

Bond strength values in the cervical third of the CG were higher than those in NA (P=.035) but similar to those of the other groups (P=.05). In the other thirds, CG and LHPA values were similar to one another (P=.05) but higher than those of NA and HHPA (P<.001). The penetration rate assessed by confocal scanning microscopy revealed similar results in the cervical third for all groups (P=.075), except for NA which provided the lowest penetration. In the remaining thirds, CG and LHPA provided the highest penetration rate (P=.015).

CONCLUSIONS

The LHPA group had no negative effects on the bond strength and penetration into the dentinal tubules of the self-etching resin cement.

Dental Cements for Luting and Bonding Restorations: Self-Adhesive Resin Cements

Self-adhesive resin cements combine easy application of conventional luting materials with improved mechanical properties and bonding capability of resin cements. The presence of functional acidic monomers, dual cure setting mechanism, and fillers capable of neutralizing the initial low pH of the cement are essential elements of the material and should be understood when selecting the ideal luting material for each clinical situation. This article addresses the most relevant aspects of self-adhesive resin cements and their potential impact on clinical performance. Although few clinical studies are available to establish solid clinical evidence, the information presented provides clinical guidance in the dynamic environment of material development.

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.

Adhesive Durability Inside the Root Canal Using Self-adhesive Resin Cements for Luting Fiber Posts

OBJECTIVES

The aim of the study was to investigate the effects of various self-adhesive resin cements on the push-out bond strengths and nanoleakage expression at the luting interfaces of fiber posts immediately and after one year of aging.

METHODS AND MATERIALS

One hundred forty-four extracted human anterior teeth were endodontically treated. After post space preparation, fiber posts were luted using five commercially available self-adhesive resin (SAR) cements and a core build-up material applied with a self-etch adhesive (BF: Bifix SE/Rebilda Post, VOCO; CSA: Clearfil SA Cement/Rely X Fiber Post, 3M ESPE; RX: RelyX Unicem 2/Rely X Fiber Post, 3M ESPE; SPC: Speed Cem/FRC Postec, Ivoclar Vivadent; SMC: Smart Cem/X Post, Dentsply; RB: Rebilda DC-Futurabond/Rebilda Post; n=22). For each group, half of the specimens were subjected to thermocycling (TC) (5°C-55°C, 10,000 cycles) and stored humid for one year at 37°C. Push-out bond strength data of six slices (thickness 1 mm) per root and nanoleakage expression of representative specimens were evaluated after 24 hours (baseline) and after TC and storage for one year (aging), respectively.

RESULTS

Bond strength differed significantly among resin cements (p<0.0005) and the location inside the root canal (p<0.0005), but not by aging (p=0.390; repeated-measures analysis of variance). SMC (14.6±5.8 MPa) and RX (14.1±6.8 MPa) revealed significantly higher bond strength compared to BF (10.6±5.4 MPa) and RB (10.0±4.6 MPa) but differed not significantly from SPC (12.8±4.8) MPa; CSA (6.1±4.6 MPa) revealed significantly lower bond strength compared to all other investigated materials (p<0.05; Tukey Honestly Significantly Different). Qualitative nanoleakage analysis revealed more silver deposits at the interface in all groups after aging. For CSA, a large amount of silver deposits inside the cement was also observed at baseline and after aging.

CONCLUSIONS

Fiber post luting using SAR cements demonstrated reliable bond strengths. Product-specific differences and initial degradation effects could be demonstrated.

Long-term bond strength of a self-adhesive resin cement to intraradicular dentin pretreated with chlorhexidine and ethanol

Abstract Introduction Self-adhesive resin cements do not require prior preparation of the tooth surface, therefore dentin pretreatments may influence long-term bond strength. Objective To evaluate the influence of 100% ethanol (ET) and 2% chlorhexidine (CL) treatment of intraradicular dentin on the long-term bond strength (BS) of a self-adhesive resin cement (SRC). Material and method 80 bovine roots were restored with fiber posts and SRC (U200 3M/ESPE) and distributed into 4 groups according to dentin treatment: Group 1 – without treatment; Group 2 – 2% CL for 1 minute; Group 3 – 100% ET for 1 minute; Group 4 – 2% CL, followed by 100% ET. The samples were cross-sectioned to obtain two sections (0.7 mm) thick for each root third: coronal, middle and apical. The immediate push-out test was carried out after 48 hours, and the long-term push-out test, after 180 days. Result The three-way ANOVA test for randomized blocks showed no difference between the BS values at 48 hours and 80 days, irrespective of the treatment and the third (p>0.05). The interaction of the treatment/third pairing was significant (p = 0.041) since the treatment with CL promoted lower BS in the coronal third, while treatment with ET promoted better BS in the apical third. Conclusion Treatment with CL and ET, separately or combined, promoted no differences between the BS values of the SRC to root dentin over time.

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

This study was undertaken to investigate whether using a protein cross-linker, 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC), improves bonding stability of fiber posts to root dentin using three resin cements. Sixty human maxillary central incisor roots were randomly divided into six groups after endodontic treatment, according to the cements used with and without EDC pretreatment. In the etch-and-rinse group, 0.3 M EDC aqueous solution was applied on acid-etched root dentin prior to Excite DSC/Variolink II for post cementation. In the self-etch and self-adhesive groups, EDC was used on EDTA-conditioned root space prior to application of ED Primer II/Panavia F2.0 and Clearfil SA, respectively. After microslicing the root dentin, a push-out bond strength (BS) test was performed immediately or after one-year of water storage for each group. Data were analyzed using three-way analysis of variance and Tukey tests (α=0.05). A significant effect of cement type, time, EDC, and Time × Cement and Time × EDC interactions were observed (p≤0.001). EDC pretreatment did not affect immediate bonding of the three cements (p>0.05). Aging significantly reduced the BS in all the groups (p≤0.001), but EDC groups exhibited a higher BS compared with the respective control groups (p<0.001). Despite the significant effect of aging on decreasing the BS of fiber post to radicular dentin, EDC could diminish this effect for the three tested cements.