Evaluation of different desensitizing agents effect on shear bond strength of adhesive resin cement to dentin

Desensitizing agents can inhibit the bonding strength between dentin and adhesive resin cement. This study evaluated the effects of different desensitizing agents on the shear bond strength of adhesive resin cement to dentin. Sixty freshly extracted and caries free teeth were classified into five experimental groups, randomly (n?=?12). Each group was treated with a different desensitizing agent (Teethmate, Shield Force Plus, Admira Protect and Ultra-Ez) respectively, except for an untreated control group. After desensitizing agents and adhesive resin cement were applied to each dentin surface, all specimens were stored in incubator at 37?°C for 24?h. The shear bond strength was tested with a Universal testing machine at a 0.5?mm/min crosshead speed. Data were analysed by using a statistical software (SPSS 22). The results of the measurements were analysed by Kruskal Wallis test with Bonferroni correction and multiple comparisons were made by Wilcoxon test (p???.01). Specimens were examined by a scanning electron microscope, additionally. The Shield Force Plus showed significantly the highest shear bond strength compared with other groups (p?<?.01). Ultra-Ez showed the lowest shear bond strength (p?>?.01). There was no significant difference among Teethmate and Admira Protect groups (p?>?.01). Desensitizing agents containing resin monomers increased the bonding strength, however desensitizers containing calcium phosphate, potassium nitrate and fluoride did not effect the bonding strength of resin cement to dentin.     

Mechanical properties of flared root canals restored with fiber post and chemically activated resin: study using push-out bond strength and fracture load tests

This study aimed to evaluate the fracture load and push-out bond strength of flared root canals restored with different procedures, including a technique with a fiber post and a chemically activated resin composite. Eighty human canines were selected and treated endodontically. Two methodologies were used: push-out and fracture load. The teeth were divided into four groups: Cast metal core (CMC); PAN (direct anatomic post); PAC (fiber post and accessory posts); and PE (fiber post with chemically activated resin composite). For the fracture load test, the samples were submitted to load application in a universal testing machine. The fracture mode was evaluated visually. Forty other samples were submitted to the push-out test. The fracture load (n = 10) and the bond strength (n = 10) were analyzed by analysis of variance and Tukey tests (α < 0.05). CMC presented the highest fracture load (p < 0.05), and no significant differences were observed in the fracture load values for Groups PAN, PAC, and PE. CMC presented 90% of unfavorable failures; PAN and PAC, the remaining 10% of these failures. PE presented only favorable failures. PAC presented lower push-out bond strength values. The fracture load for CMC procedure was higher than that of the others, but presented 90% unfavorable fractures, indicating the use of any of the glass fiber post techniques evaluated for restoring flared root canals due to favorable fracture modes.     

Impact of conditioning regimens and time on adhesion of a fiber post to root dentin using two resin cements

The aim of this study was to evaluate the influence of irrigation protocols on the bond strength of a glass fiber post bonded to dentin using two resin cements. In 200 root-filled teeth, post space was prepared and divided into five groups (n?=?40) based on the irrigation protocol: group 1 (3% sodium hypochlorite), group 2 (3% sodium hypochlorite – 17% Ethylene diamine tetraacetic acid), group 3 (a mixture of sodium hypochlorite and etidronic acid), group 4 (sodium hypochlorite – QMix), and group 5 (distilled water). Samples were subdivided into two subgroups (n?= 10) and fiber posts were cemented using subgroup A (Self-adhesive dual-cure resin cement; SEA) or B (dual-cure resin cement following an etch-and-rinse protocol, ER). Push-out bond strength was performed after 24 h and four months (n?= 10) and failure modes were categorized. Statistical analysis of data was carried out by appropriate analyses (p < 0.05). The irrigation protocol and the resin cement had a significant impact on push-out bond strength. Subgroup A group showed lower bond strength than B at both time periods when 3% NaOCl–17% EDTA and 1:1 mixture of 6% NaOCl + 18%EA protocols were used. Three percent NaOCl used in combination with 17% EDTA or QMix significantly decreased the push-out bond strength of ER at the end of four months (p < 0.05). In conclusion, dual-cure resin cements bonded with etch-and-rinse protocol showed highest bond strength when a mixture of NaOCl and etidronic acid was used as root canal irrigant. These values were differentially influenced by time.     

Long-term bond strength of fiber posts cement to dentin with self-adhesive or conventional resin cements

The aim of this study was to evaluate the immediate and the long-term push-out bond strength of glass fiber posts (GFP) cemented with conventional or self-adhesive dual-curing resin cements, at different root depths. Prior to cementation, the GFP (Reforpost #3, Angelus) were etched with 37% phosphoric acid for 30 s followed by silane for 1 min. Thirty canine roots were divided into two groups (n = 15) according to resin cement type: ARC – dual resin cement (RelyX ARC/3M ESPE) combined with an three-step etch-and-rinse adhesive (Adper Scotch Bond Multi-Purpose Plus 3M/ESPE) or U200 – self-adhesive resin cement (RelyX U200/3M ESPE). The manufacturer’s instructions were followed. After 48 h, the roots were cross-sectioned at three different depths, resulting in serial slices corresponding to the cervical, middle, and apical root thirds. Slices were randomly divided into two groups, according to the period of water storage prior to push-out bond strength analysis: 48 h or 180 days. The data (MPa) were analyzed using three-way ANOVA for randomized blocks (p < 0.05), which showed no significant interaction between the three factors (p = 0.716). The main study factors were also proven not significant (cement: p = 0.711; time: 0.288; root third: p = 0.646). In conclusion, root depth, cement type (self-adhesive or conventional), and storage in water for 180 days did not influence the bond strength of GFP to intracanal dentin.     

Effect of cyclic loading and resin cement type used for luting fiber posts on bond strength at different root levels of crown-restored human teeth

Objective: This study aimed to evaluate the bond strength (BS) of glass fiber posts (GFP) at different root levels when luted with conventional or self-adhesive cements in crown-restored human premolars subjected, or not, to cyclic mechanical loading.

Materials and Methods: Sixty lower premolar roots were endodontically treated and prepared for a GFP system. Half of the roots (n = 30) had their posts cemented with a self-adhesive resin cement, while the remaining roots followed a three-step conditioning method: acid etch, bonding agent, and a conventional resin cement. Metal crowns were luted onto the post-core preparations and the specimens were embedded to simulate the periodontium. Half of the specimens from each group (n = 15) were submitted to cyclic loading simulations (130 N; 2.0 Hz) and then sections were obtained from each root for the pushout BS test.

Results: Independently of the cyclic loading and the root level tested, the conventional resin cement provided significantly higher values of BS (p = 0.002). For either cement or either root level, cyclic loading caused a significant decrease in BS values (p = 0.023). The Tukey test indicated that, regardless of the resin cement used or the cyclic loading, BS was highest at the middle and cervical thirds of the root (p = 0.026), and their values did not differ between themselves.

Conclusions: When used for luting GFP, self-adhesive resin cement resulted in lower pushout BS than the conventional counterpart, with cyclic loading causing a decrease in BS of the GFP to dentin for both resin cements.     

Influence of surface energy parameters of dental self-adhesive resin cements on bond strength to dentin

The purpose of this study was to determine the surface energy parameters of dental self-adhesive resin cements (SRCs) and to measure their bond strength to dentin. Six dental SRCs (RelyX Unicem Clicker, RU; Maxcem Elite, ME; BisCem, BC; Clearfil SA Luting, SA; Multilink Speed, MS; seT PP, SP) and one resin-modified glass ionomer cement (RelyX Luting 2, RL; control) were tested. Smear layer-covered bovine dentin was used as bonding substrate. Using the dynamic sessile drop method, surface energy, surface energy components, degree of hydrophobicity/hydrophilicity (expressed as ΔG _sws using thermodynamic notation), and apparent surface energies for each material were calculated. The luting cements were bonded to the dentin and stored in water at 37?°C for 24?h prior to shear bond strength test (n?=?10). Pearson correlation analysis was applied to detect possible correlations between surface energy parameters and measured shear bond strength (α?=?0.05). RU, SA, and MS produced negative ΔG _sws values (hydrophobic), whereas ME, BC, SP, and RL yielded positive ones (hydrophilic). RU had the highest value among all six SRCs tested, the value for MS being statistically equivalent (p?=?0.785). The base component, ΔG _sws, and surface energy determined with water showed significant negative linear correlations with dentin bond strength (r/p?=??0.801/0.030, ?0.900/0.006, and ?0.892/0.007, respectively). These results suggest that bonding to smear layer-covered bovine dentin was governed by the base component and the hydrophobicity/hydrophilicity of the SRCs.     

Test methods for bond strength of glass fiber posts to dentin: A review

ABSTRACT

In this paper, a review of the test methods for bond strength of glass fiber posts to dentin is presented. The main variables that influence the bond strength tests are related to substrate, to specimen properties, specimen preparation, and test methodology. The impact of these variables on the test outcome is analyzed. The search was performed on studies published between 2007 and 2015. Most of the tests carried out, in the literature, were the push-out (75%), pull-out (13%), and microtensile (11.9%) tests, showing an inversion compared to the results found in studies published between 2005 and 2010, when push-out test was used in a proportion of 2% and microtensile test in a proportion of 67%. The push-out test emerged as a practical tool for evaluating the interfacial shear strength between fiber post and root canal walls.     

Effect of timing for core preparation,luting cement type and root level on adhesion of fiber posts to intraradicular dentin

This study assessed the effect of timing of core preparation and luting cement on adhesion of fiber-reinforced composite (FRC) posts on different levels of intraradicular dentin when cemented with either conventional dual-polymerized or self-adhesive resin cement. Single-rooted human teeth (N = 80) were endodontically treated and randomly divided into 2 groups (n = 40) according to resin cement: (a) Conventional dual resin cement (Variolink II, V) or (b) Self-adhesive resin cement (RelyX U200, R). They were further divided into two subgroups according to timing of core preparation (n = 20): (a) immediate (i) or (b) delayed (d). FRC posts (Cytec Blanco) were cemented and the roots were sliced into discs at the coronal, middle, and apical levels. Push-out tests were then performed in a Universal Testing Machine (1 mm/min). Data (MPa) were analyzed using three-way ANOVA and Tukey’s tests considering the factors ‘core preparation time’, ‘luting cement’, and ‘root level’ (α = 0.05). Type of luting cement (p < 0.001), time of core preparation (p < 0.001), and root level (p < 0.001) significantly affected the bond strength results. R cement was more significantly affected by core preparation time (Ri: 2.91 ± 1.1; Rd: 4.83 ± 1.68) compared to V cement (Vi: 2.92 ± 1.63; Vd: 2.65 ± 1.6) (p < 0.05). Coronal region demonstrated significantly higher bond strength values than those of middle and apical third in all groups (coronal: 4 ± 1.9; middle: 3.1 ± 1.4; apical: 2.4 ± 1.1) (p < 0.05). Adhesive failure between cement and dentin was the most frequent (64%) followed by adhesive failure between cement and post (18%). Delayed core preparation can improve bond strength of FRC posts to intraradicular dentin when cemented with self-adhesive cement compared to conventional dual-polymerized resin cement.     

Bond strength evaluation of composite resin bonded to glass ionomer cements after different periods of setting

This study investigated the time elapsed after setting of glass ionomer cements on the bond strength to composite resin restorations. Bovine incisors received cavity preparations on the buccal surface (6 mm×6 mm×2 mm) and the specimens were tested according to cement type (conventional and resin-modified) and time elapsed before performing the restorations: GC10m: conventional glass ionomer cement and 10 min time elapsed after setting; GC24h: conventional cement and 24 h after setting; GC7d: conventional cement and 7 days after setting; GRM10m: resin-modified glass ionomer cement and 10 min after setting; GRM24h: resin-modified cement and 24 h after setting; and GRM7d: resin-modified cement and 7 days after setting. Specimens were subjected to micro-shear testing and the data were analyzed by Analysis of Variance and Tukey′s test (p=0.05). Bond strength of restorations performed on conventional cement after 10 min of time elapsed presented the lowest mean values and differed statistically from values at 24 h and 7 days. Resin-modified cement after 24 h presented the highest mean values and differed statistically from values at 10 min and 7 days. The time elapsed after setting of glass ionomer cement may interfere in the bond strength to composite restorations.     

Effect of the interfacial area measurement parameters on the push-out strength between fiber post and dentin

PurposeTo verify the influence of different instruments and operators on the bonding interfacial area and on the push-out bond strength values.Material and methodsFifteen anterior human teeth (n=15) were selected, cleaned and standardized to 15 mm length. Root canals were prepared in 12 mm and the fiber posts were cemented using the RelyX U-100 cement. Three slices were obtained per tooth (N=45) and submitted to the push-out bond strength test. The bonding interfacial area (mm²) of each specimen was calculated based on the disc slice dimensions: coronal and apical diameter and height. The bonding area of each specimen was used to calculate the bond strength (Mpa). The dimensions were analyzed by different operators, using two instruments: G1 – Operator A with a digital caliper; G2 – Operator A with a stereomicroscope; G3 – Operator B with a digital caliper; G4 – Operator B with a digital stereomicroscope; G5 – Operator C with a digital caliper; G6 – Operator C with a stereomicroscope. The mean area was submitted to inter-operator and intra-operator analyses, while the mean area and mean of bond strength were submitted to the 2-way ANOVA with repeated measures and the Tukey test (α=0.05).ResultsThe inter-operator kappa was 0.83 to the digital caliper and 0.91 to the stereomicroscope, while the intra-operator kappa was 0.76. The operator and the measurement instrument influenced the interfacial bonding area (p=0.000 and p=0.001) and the push-out bond strength values (p=0.000 and p=0.000, respectively) of the disc slices.ConclusionThe final push-out bond strength values are influenced by the measuring instrument and by the measurer operator.     

Bond strength and chemical interaction of self-adhesive resin cements according to the dentin region

The aim of the study is to evaluate the effectiveness and level of chemical interaction of self-adhesive resin cements (SRCs) according to the dentin region. One hundred eight sound human third molars and three SRCs were selected: Bifix SE (Voco), Maxcem Elite (Kerr), and RelyX U200 (3M ESPE). Ninety human molars were used for the bond strength test and 18 teeth for the X-ray diffraction (XRD) characterization. A flat surface of superficial, deep, or axial dentin was exposed. For bond strength evaluation, 90 indirect composite resin restorations (10 mm in diameter, 2.0 mm-thick) were built and cemented with one of the SRCs according to the manufacturer's instructions. The restored teeth were then cut into sticks with cross-sectional areas of 0.8 mm² and tested in tensile at a speed of 0.5 mm/min (n=10). The results of bond strength were statistically analyzed by two-way ANOVA and Tukey's test (α=0.05). The fractured specimens were classified under SEM. The remaining teeth were further sectioned in order to build dentin fragments with 2.0 mm² of area and 0.2 mm in thickness for XRD analysis. In general, significantly higher bond strength was found when bonding to axial and deep dentin compared to superficial dentin. Comparing the bonding effectiveness of the SRCs, taking into account the mean bond strength obtained in the 3 dentin regions, the study found no significant difference (p>0.05). Although RelyX U200 showed similar bond strength irrespective of the dentin region (p>0.05), the bonding results of the other 2 SRCs varied significantly (p<0.05). There was a higher incidence of cohesive failure in the SRCs for all groups. The XRD analysis detected different perceptual reductions of hydroxyapatite crystallinity for all SRCs, indicating a particular chemical interaction in each experimental condition. Thus, it can be concluded that the bond strength and chemical interaction of the SRCs can vary significantly according to the dentin region.     

Adhesion of bulk-fill resin composites as core and intraradicular post materials only versus the use of glass-fiber posts in different regions of root dentin

This study assessed adhesion of bulk-fill resin-composites as core and post materials only versus the use of fiber resin composite (FRC) posts. Human teeth (N?=?84) were cut at the CEJ and endodontically treated and randomly divided into seven groups: TP: Titanium post (Flat Head T); SFRC: S2-glass FRC (Pinpost); EFRC1: E-glass FRC (GC Everstick) directly bonded; GFRC: E-glass FRC (Glassix Nordin); EFRC2: E-glass FRC (Everstick); BF1: Bulk-fill resin (Surefill SDR); BF2: Bulk-fill resin (SonicFill). Groups TP, SFRC, EFRC and GFRC were cemented (Panavia 21), while other groups were bonded directly to the intraradicular dentin. The core parts were constructed using a resin composite (G-aenial) except for Groups BF1 and BF2. The core-cervical dentin interface was loaded under shear forces. Push-out tests were performed in a Universal Testing Machine (1?mm/min). Data (MPa) were analyzed using two-way ANOVA and Tukey`s tests (α?=?0.05). Not the root level (p?>?0.05) but the type of core and post material significantly affected shear and push-out bond results (p?<?0.001). BF1 (9.2?±?2.1) and BF2 (9.3?±?3.1) showed significantly lower bond strength to the cervical dentin (p?<?0.05) compared to other groups (11.6?±?2.5–19?±?6.8). FRC post types did not show significant difference being higher than those of TP, BF1 and BF2 (0.57?±?0.37–2.34?±?1.98) (p?>?0.05). Partial cohesive core fracture was more common while BF1 and BF2 showed exclusively adhesive failures. Cohesive failure in the cement was frequent in Group TP (53%) compared to other groups (3–24%). BF1 and BF2 presented exclusively complete adhesive failure of the bulk-fill material.     

Er,Cr:YSGG laser irradiation influence on Y-TZP bond strength to resin cement

The aim of this study was to evaluate Y-TZP surface pretreatment with different protocols on microshear bond strength (μSBS) ceramic-cement interface. One hundred and sixty pre-sintered IPS e-max ZirCAD (Ivoclar-Vivadent) blocks were randomly divided into sixteen groups according to surface treatment (n=20): G1- no treatment (control); G2- ceramic primer; G3- tribochemical silica coating; G4- tribochemical silica coating+primer; G5- airborne particle abrasion (Al₂O₃); G6- airborne particle abrasion (Al₂O₃)+primer; G7- Er,Cr:YSGG laser; G8- Er,Cr:YSGG laser+primer. All specimens were sintered before surface treatment, except lasers groups, which were sintered after laser irradiation. Ceramic blocks were bonded with Panavia F resin cement (Kuraray, Okayama, Japan) (n=10) or RelyX ARC (3M ESPE, St. Paul, MN, USA) (n=10). The μSBS tests were carried out in a universal testing machine at a speed of 1mm/min after 24 h (n=5) or 6 months storage (n=5). Differences were found for both resin cements and storage conditions in relation to μSBS values (p<0.05). However, no significant difference for interaction between factors was observed in cemented blocks with RelyX ARC. Panavia F resin cement showed significant differences for interaction between factors (p<0.05). Laser treatment was not sufficient to increase μSBS values between Y-TZP and resin cements. Tribochemical silica coating followed by primer achieved the highest immediate μSBS values. The storage did not affect negatively μSBS values to both evaluated cements.     

The effect of intracanal placement of various medicaments on the bond strength of three calcium silicate-based cements to root canal dentin

This study aimed to evaluate the effect of intracanal placement of various medicaments on the bond strength of ProRooT MTA, Biodentine, and Endosequence root repair material (ERRM) putty. Ninety extracted human mandibular premolar teeth were decoronated and instrumented using Protaper Next rotary system and #1 to #6 Peeso reamers. The prepared teeth were randomly divided into six groups according to the intracanal medicaments: Group 1: double antibiotic paste (DAP) consisting of metronidazole and ciprofloxacin; Group 2: Triple antibiotic paste (TAP) with cefaclor; Group 3: TAPwith clindamycin; Group 4: amoxicillin and clavulanic acid (Augmentin®); Group 5: calcium hydroxide (CH); Group 6: control (no medicament) (n = 15). Parallel transverse sections were obtained in the coronal to the apical direction (4 slices/ tooth) and were divided into three subgroups according to the cements: Group A: ProRoot MTA; Group B: Biodentine; Group C: ERRM (n = 20 slices/subgroup). A push-out test was used to measure bond strength. Data were analyzed using two-way analysis of variance and Tukey’s post hoc test. The bond strength was significantly lower for DAP and TAPs than for Augmentin®, CH, or the control (p < 0.05). Biodentine and ERRM had significantly higher bond strength values than ProRooT MTA (p < 0.05) regardless of the intracanal medicaments tested, while no significant difference existed between Biodentine and ERRM (p > 0.05). While the application of DAP or TAPs decreased the bond strength, application of CH or Augmentin® did not. ERRM and Biodentine had higher bond strength values than ProRoot MTA.     

Influence of the ER,CR:YSGG laser and different irrigation methods on push-out bond strength of fiber post

Er,Cr:YSGG lasers are currently being investigated for disinfecting the root canal treatment. The aim of this study was to compare the effects of various irrigation protocols on push-out bond strength of fiber posts. Fifty maxillary anterior teeth were divided into five groups (n = 10) according to the protocol that applied into the post space. Group-1: distilled water, Group-2: 5% NaOCl, Group-3: 2% CHX, Group-4: Er,Cr:YSGG laser (1.5 W, 20 Hz, 85 air, 75 water, 26.7 J/cm²), Group-5: Er,Cr:YSGG laser (1.25 W, 50 Hz, 34 air, 24 water, 12.7 J/cm²). Fiber posts were cemented with resin cement. The remaining part of the root, three slices were obtained from each specimen and push-out test was performed. One-way ANOVA and Duncan’s test at a 5% level of significance were used for the statistical analysis. Post space irradiation with Er,Cr:YSGG laser (1.5 W 20 Hz, 85 air, 75 water, 26.7 J/cm²) increases push-out bond strength of fiber post to root canal dentin. Further investigations are needed to establish and optimize ER,Cr:YSGG laser parameters to increase the push-out bond strength of fiber posts.     

Alpha-hydroxy glycolic acid for root dentin etching: Morphological analysis and push out bond strength

The purpose of this study was investigated the use of α-hydroxy glycolic acid as a dentin etchant for adhesive procedures in the root canal. The etching pattern of glycolic acid and mineral content distribution of root canal dentin were assessed by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), respectively. The effect of glycolic acid surface etching on the push out bond strength of fiber post to root dentin was assessed using three adhesive systems: Single Bond Universal [SBU], Scotchbond Multipurpose [SBMP], and Ambar [AM]. The 37% phosphoric acid was used as a control group. The bond strength values were statistically compared using ANOVA/Fisher LSD tests (α = 0.05). SEM revealed similar etching patterns for phosphoric acid and glycolic acid. Both acids also shared similar interfacial morphology of the hybrid layer. EDS showed similar levels of Ca and Mg after treatment with glycolic acid when compared with phosphoric acid. When the P level was compared, it was observed that phosphoric acid caused greater removal of P. The push out bond strengths were statistically similar between glycolic acid and phosphoric acid in all groups (p > 0.05). Comparisons using post hoc Fisher LSD test showed that the bond strengths in the SBU and SBMP groups were not significantly different from each other (p > 0.05). The bond strength in the AM group was similar to that in the SBMP group (p > 0.05); however, it was significantly lower than that in the SBU group (p < 0.05). It can be concluded that the glycolic acid effectively etched root dentin surfaces, resulting in a surface pattern, hybrid layer, and push out bond strength similar to those produced by traditional phosphoric acid. Therefore, glycolic acid may be recommended as a suitable root dentin surface etchant for adhesive restorative procedures.     

Effect of the frequency of mechanical pulses for fatigue aging testing on push-out bond strength between glass fiber posts and root dentin

The aim of this study was to evaluate the influence of the frequency of mechanical pulses during mechanical fatigue aging on bond strength between glass fiber posts and root dentin. Fiber posts were adhesively cemented in 30 bovine roots and the core was built up with composite. All specimens were subjected to mechanical cycling (45° angle; 37 °C; 50 N; 2×10⁶ pulses) at different frequencies: 2, 4, and 8 Hz. After the fatigue, each specimen was submitted to push out test. The bond strength was calculated for data analysis (one-way ANOVA, p = 0.05). The frequency did not affect the push-out (p = 0.7). The main failure mode was between dentin and cement in all groups. The mechanical pulses were not influenced by the bond strength between root dentin and fiber posts. Thus, it is possible to decrease the time-consuming in vitro tests involving posts without damaging the reliability of the test.     

The effect of canal cleansing protocols on cementation of a fiber post to saliva-contaminated root canals

Objective: This study investigated the effect of saliva contamination and cleansing effect of a self-etching primer (SEP), phosphoric acid (PA), chlorhexidine (CHX), and ethanol (EtOH) on the microtensile bond strength (μTBS) of a fiber post cemented with a self-adhesive resin cement (SAC) to root canal dentin.

Material and methods: Sixty human lower premolar roots were randomly divided into 10 groups: (1) no saliva contamination, no cleansing (Control); (2) no saliva contamination, cleansing with SEP (NC-SEP); (3) no saliva contamination, cleansing with PA (NC-PA); (4) no saliva contamination, cleansing with CHX (NC-CHX); (5) no saliva contamination, cleansing with EtOH (NC-EtOH); (6) with saliva contamination, no cleansing (SC-NC); (7) with saliva contamination, cleansing with SEP (SC-SEP); (8) with saliva contamination, cleansing with PA (SC-PA); (9) with saliva contamination, cleansing with CHX (SC-CHX); (10) with saliva contamination, cleansing with EtOH (SC-EtOH). After cementation of posts, the roots were transversally sectioned to obtain six slices (n = 36) followed by μTBS test. Data were analyzed with ANOVA and Tukey HSD tests (p = 0.05).

Results: Saliva contamination and cleansing methods had a significant effect on μTBS values (p < 0.0001). All cleansing agents improved bond strengths when compared with Control and SC-NC. Cleansing with CHX and ethanol showed lower μTBS values than phosphoric acid and SEP, regardless of saliva contamination (p < 0.05).

Conclusions: Saliva contamination negatively affected bonding performance of SAC to root dentin. However; SEP, PA, CHX and EtOH can be used on contaminated dentin surfaces to optimize bonding performance of self-adhesive cements.     

Degree of conversion and adhesion of methacrylate-based resin cements with phosphonic or phosphoric acid acrylate to glass fiber posts at different regions of intraradicular dentin

This study evaluated the degree of conversion (DC) and adhesion of methacrylate-based resin cements to glass fiber posts at different regions of intraradicular dentin. Single-rooted teeth (N?=?24, n?=?12 per group) were cut at the cement–enamel junction (CEJ), endodontically treated and post space (depth?=?8 mm) was prepared. Teeth were randomly divided into two groups according to the resin cements: (a) Group ML: methacrylate-based cement with phosphonic acid acrylate (Multilink Automix, Ivoclar Vivadent); (b) Group RXU: methacrylate-based cement with phosphoric acid acrylate (RelyX Unicem 2 Automix, 3 M ESPE). Fiber-reinforced composite root posts (RelyX Fiber Post, 3 M ESPE) were cemented according to the manufacturers’ instructions of the resin cements. Root slices of 2-mm thickness (n?=?3 per tooth) were cut below the CEJ 1, 3, and 5 mm apically. The DC of each section was analyzed with micro-Raman spectrometer and push-out test was performed in the Universal Testing Machine (0.5 mm/min). After debonding, all specimens were analyzed using optical microscope to categorize the failure modes. While data (MPa) were statistically evaluated using Kruskal Wallis, Mann–Whitney U tests for DC data 3-way ANOVA and Tukey’s tests were used (α?=?0.05). Regardless of the resin cement type, the mean push-out bond strength results (MPa), were significantly higher for the coronal slices (ML: 9.1?±?2.7; RXU: 7.3?±?4.1) than those of the most apical ones (ML: 7?±?4.9; RXU: 2.89?±?1.5) (p?=?0.002). Resin cement type and (p?p?=?0.002) significantly affected the DC values, while the interaction terms were not significant (p?=?0.606). Overall, DC was significantly higher for ML (67?±?8.2%) than RXU (26?±?8.8%) (p?相似文献   

Shear bond strengths of six different porcelain laminate veneer materials cemented to enamel with two different MDP-containing resin cements

Purpose: To compare the shear bond strengths of six different porcelain laminate veneer (PLV) materials cemented to enamel with two different MDP-containing resin cements. Materials and methods: Totally 120 disc specimens were fabricated with In-Ceram alumina (ICA), Turkom-Cera^TM (TCR), IPS Empress (IPS), IPS Empress-II (IPS2), Finesse (FNS), and Ceramco-3 (CER) ceramic systems (n = 20). Sixty specimens were cemented with self-adhesive resin cement (Clearfil SA), and 60 specimens were cemented with self-etch resin cement (Panavia F2.0) to enamel. Thus, 120 PLV–enamel specimens were assigned to 12 experimental groups (ICA/Pv, ICA/Cf, TCR/Pv, TCR/Cf, IPS/Pv, IPS/Cf, IPS2/Pv, IPS2/Cf, CER/Pv, CER/Cf). Shear force was applied on PLV–enamel interfaces until failure. Obtained data were statistically analyzed with ANOVA and t-tests. Results: Obtained shear bond strength values (SBSV) ranged as follows, respectively; TCR/Cf (7.70 MPa), FNS/Cf (7.57 MPa), TCR/Pv (6.91 MPa), ICA/Pv (5.05 MPa), CER/Pv (4.75 MPa), IPS2/Cf (4.66 MPa), FNS/Pv (4.43 MPa), IPS2/Pv (3.97 MPa), CER/Cf (3.82 MPa), IPS/Pv (3.62 MPa), ICA/Cf (3.59 MPa), IPS/Cf (3.11 MPa). Highest SBSV were obtained in TCR groups (7.70 MPa for TCR/Cf and 6.91 MPa for TCR/Pv) and lowest SBSV were obtained in IPS groups (3.11 MPa for IPS/Cf and 3.62 MPa for IPS/Pv) in both resin cements. No significant bond strength difference was found between two resin cements. Conclusions: TCR groups showed highest SBSV; lowest SBSV were obtained with both IPS PLVs. The resin cement type did not significantly affect the bond strength value of a ceramic type, except for the Finesse system.