Dual-cure Resin Cement Research Articles

Comparative Evaluation of Bond Strengths Between Dual Cure Resin Cement and Light Cure Resin Cement in Root Surface Indirect Restorations: An In Vitro Analysis Study.

Aim The aim of this study was to evaluate the shear bond strength betweendual cure and light cure resin cements in root surface indirect restorations. Materials and methods Ten recently extracted human teeth were selected. Cylindrical blocks of resin were prepared and bonded nearthe Cemento-Enamel Junction (CEJ) of the prepared teeth to mimic the restoration at the root surface.The samples were randomly luted to the root surface using the light cure (Calibra Veneer, Dentsply Sirona, India) and dual cure (Fusion Ultra D/C, DenPro, USA) formingtwo groups. The bond strength was checked using the INSTRON 3000 device (INSTRON, MA, USA). The point of fracture of the prepared sample from the tooth surface was noted. All readings were tabulated and further statistically analyzed. Results On comparing the two groups, it was found that the light cured resin had a greater mean shear bond strength (57 N) than the dual cure resin cement (41 N).The difference in the mean value of the shear bond strength between two resin cements was found to be statistically not significant according to independent T-test analysis using Levene's Test (P>0.05). Conclusion From the results obtained and within the limits of the study conducted, we can infer that Calibra Veneer is a more viable option for luting to the root surface area. On the other hand, Fusion Ultra Dual cure resin cement seems to have similar results but has a lower bond strength than the other.

Effect of 4-META on microtensile bond strength of cements to ceramics

Background: This study assessed the effect of different concentrations of 4-methacryloyloxyethy trimellitate anhydride (4-META) added to silane on microtensile bond strength (µTBS) of light-cure and dual-cure resin cement to hybrid and zirconia-reinforced lithium silicate ceramics. Materials and Methods: This in vitro, experimental study was conducted on 32 Celtra Duo and 32 VITA Enamic ceramics bonded to Allcem Veneer light-cure and Allcem dual-cure resin cements using silane impregnated with 4-META in 0%, 2.5%, 5%, and 10 wt% concentrations in 16 groups (n = 4). The µTBS of specimens was measured by a universal testing machine and analyzed by the Kruskal–Wallis and Mann–Whitney tests, and the mode of failure was determined under a stereomicroscope and analyzed by the Chi-square test (alpha = 0.05). Results: The lowest mean µTBS was recorded in the Enamic ceramic group with 4-META (0%) bonded to dual-cure cement (14.26 MPa), and the highest mean µTBS was recorded in Enamic ceramic with 4-META (10%) bonded to light-cure cement (18.59 MPa) (P < 0.001). The µTBS of Celtra Duo was significantly higher than that of Enamic in bonding to light-cure cement using 4-META (2.5%) (P = 0.003). All failures (100%) were adhesive in most groups. The frequency of adhesive failure was the lowest (90%) in Celtra Duo bonded to dual-cure cement with 4-META (5%). Conclusion: According to the results of this pilot study, the addition of 4-META (10%) to silane caused a significant improvement in µTBS to light-cure cement. The addition of 4-META in all concentrations significantly improved the µTBS to Enamic ceramic in the use of dual-cure cement; however, it had no significant effect on µTBS of Celtra Duo. Nonetheless, the results should be interpreted with caution due to the relatively small sample size.

Assessment of Various Post Systems’ Fracture Resistance after Endodontic Treatment

ABSTRACT Objectives: The study’s objective is to evaluate the fracture resistance of a tooth that has had endodontic treatment and has been rebuilt using various post and core systems. Materials and Methods: Thirty-six extracted premolar teeth of similar sizes were picked, and at random, they were separated into three groups: group A received stainless-steel posts, group B received zirconia fiber posts, and group C received glass fiber posts. Dual-cured resin cement was used to cement each post. The acrylic resin blocks have samples imbedded in them. Additionally, fracture loads were measured while a compressive force was given to the tooth at a crosshead speed of 1 mm/minute. The one-way analysis of variance F-test and post hoc Tukey’s test were then used to analyze the results. Results: When the mean values and standard deviation were compared, it was found that glass fiber posts had the highest fracture resistance, followed by posts made of zirconia fiber, while stainless-steel posts had the lowest fracture resistance Conclusion: When compared to zirconia posts and stainless-steel posts, glass fiber posts had the highest level of fracture resistance.

Fracture strength of endocrowns after thermomechanical aging.

This in-vitro study aimed to evaluate the fracture strength (FS; N) of composite, feldspathic, and glass-ceramic computer-aided design/computer-aided manufacturing (CAD/CAM) endocrowns after thermomechanical aging. Seventy non-carious human molars were randomly divided into seven groups, according to the CAD/CAM material used for endocrown fabrication. Intact molars without cavity preparations were used as control (n = 10). Following endodontic treatment, standardized endocrown cavities were prepared and endocrowns were fabricated using composite (Cerasmart270, CS and Grandio Blocs, GB), fired and milled zirconia-reinforced lithium silicate (Celtra Duo, CD), leucite-reinforced feldspar ceramic (LRF Initial, LRF), and feldspathic (Cerec Blocks, CE) materials which were luted with universal adhesive (Futurabond U; Voco) and dual-cure resin cement (Bifix QM). Following thermocycling for 20,000 cycles and 480,000 load cycles in a chewing simulator (CS-4.2, SD Mechatronik), FS was evaluated (Instron). Data were analyzed with one-way ANOVA and post hoc Tukey's tests (p < 0.05). FS was significantly influenced by the tested material (p = 0.00). CS had the highest FS, which was not significantly different from intact molars and fired CD (p > 0.05). There were no significant differences in FS between LRF, GB, and CD, which were significantly higher than CE. Most of the failure modes of CS, CD, and GB were repairable, whereas those of CE were irreparable. All the tested materials withstood clinically relevant axial forces. Composite endocrowns exhibited more favorable fracture pattern, whereas feldspathic and leucite-reinforced feldspar ceramic endocrowns exhibited mostly irreparable fractures.

Bond Strength of Two Resin Cements with Leucite-reinforced Ceramic Using Different Bonding Agents.

To compare the bond strength of two resin cements to leucite-reinforced ceramics using three different boding agents and evaluate the compatibility of bonding agents. Twenty extracted sound human molars were sectioned horizontally 2-3 mm above the cementoenamel junction (CEJ). CAD/CAM ceramic blocks for inLab were also sectioned to create 4 mm thick and bonded to the dentin. The adhesive groups assigned were divided into four adhesive groups: Group I: Variolink II dual-cure resin cement and Scotchbond Multi-Purpose Plus adhesive, group II: Multilink Automix dual-cure resin cement and Multilink primers, group III: Multilink Automix and Clearfil SE bond 2 (CSE2) adhesive, group IV: Multilink Automix and CSE2 with light curing after adhesive application. Five specimens of each group were sectioned perpendicular to obtain six microsticks of 1 × 1 mm width from each sample. Microtensile bond strength data were expressed in MPa. Fracture modes (FrMs) analyzed for the surfaces were divided into six patterns. Microtensile bond strength data were statistically analyzed with one-way ANOVA and Tukey post hoc tests (α = 0.05). T-test was performed at the 5% significance level to analyze groups III and IV with and without light curing. Group I showed the highest μTBS average of 13.67 MPa, group IV showed 12.26 MPa, group III showed 12.15 MPa, and group II showed the lowest average of 10.84 MPa. No significant differences were found between the bonding agents. However, the six types of failure modes, although all observed, were characterized by the adhesive system: Type I: adhesive failure of laminated dentin and ceramic; type II: adhesive failure of laminated ceramic; type III: adhesive failure of laminated dentin; type IV: cohesive failure of luting agent; type V: cohesive failure of dentin, and type VI: mixed failure of adhesion and cohesion. As a result, the FrM most commonly observed was the adhesive failure at the luting cement-ceramic block interface. The combination of resin cements and bonding agents did not significantly affect the bond strength of CAD/CAM ceramic restorations and dentin. Several universal bonding agents are currently available for direct and indirect bonding, and using the same bonding agent for direct and indirect restorations could simplify inventory and benefit routine clinical practice. How to cite this article: Aida N, Koi K, Amaya-Pajares SP, et al. Bond Strength of Two Resin Cements with Leucite-reinforced Ceramic Using Different Bonding Agents. J Contemp Dent Pract 2023;24(11):859-863.

Comparative evaluation of the shear bond strength of lithium disilicate veneers using one light-cure and two dual-cure resin cement: An in vitro study.

The present in vitro study aimed to comparatively evaluate the shear bond strength (SBS) of one light-cure and two dual-cure resin cement to bond lithium disilicate veneers. Thirty maxillary central incisors (n = 30) were procured and randomly divided into three groups of adhesive/resin cement systems, into groups of 10 each (n = 10); Group A: Adper Single Bond 2/RelyX Veneer Cement, Group B: Prime and Bond NT/Calibra, and Group C: Excite DSC/Variolink II. All the tooth samples were etched and respective bonding agent was applied. Similarly, all the laminate veneer specimens were etched, silanated, and treated with respective bonding agents before cementation with the respective resin cement. The SBS was measured in a universal testing machine with a cross-head speed of 1 mm/min. Data obtained were analyzed using the one-way analysis of variance and post hoc Tukey's test at a 5% significance level. The highest SBS was demonstrated by Group C (18.8 ± 0.92 Mpa), followed by Group B (18.4 ± 0.74) Mpa, and the least by Group A (17.4 ± 0.75 MPa). Significant differences were found between Group A, Group B, and Group C, respectively. However, Group B and Group C did not differ significantly from each other. Dual-cure resin cement have higher SBS than the light-cure variants.

Evaluation of Zirconia Paediatric Crowns and Stainless-steel Crowns using Finite Element Stress Analysis

Introduction: The aim of this study is to perform Finite Element Stress Analysis (FEA) to determine the stress that stainless-steel and zirconium materials apply to the primary teeth while under occlusal and lateral forces, in order to predict possible situations that may occur in restorative materials and dental tissues as a result of their clinical use. Objective: The study groups were as follows: stainless-steel crown cemented by glass ionomer cementand dual cure resin cement; zirconium paediatric crown cemented by glass ionomer cement and dual cure resin cement. The control group was the tooth model without decay.

The impact of CO2 laser on the bond strength of translucent zirconia and traditional zirconia with the resin cement: In vitro study

Background/Aim: The aim of this study is to compare the impact of CO 2 laser on traditional zirconia and translucent zirconia in terms of the bonding strength to resin cement. Material and Methods: In this in-vitro study 20 zirconia disks (10 mm diameter and 2 mm thickness) were assigned to two groups (n = 10). Group 1: 10 discs of traditional zirconia, Group 2: 10 discs of translucent zirconia, CO 2 lasers were used for pretreatment of zirconia surface, respectively. Dentinal disks were cemented on zirconia disk using dual-curing resin cement. Shear bond strength tests were performed at a crosshead speed of 1 mm/min after 24 h distilled water storage. Data was analyzed by T Student's test. Results: The means and standard deviations of shear bond strength values in Group 1, and Group 2 were 1.15, 0.38, 1.99 , 0.65 MPa respectively. Data showed that application of CO 2 laser resulted in a significant higher shear bond strength of resin cement to translucent zirconia ceramics (p &lt; 0.05). Conclusions: Application of CO 2 laser treatment (3W) increases the bond strength to the resin cement of translucent zirconia compared to traditional zirconia.

An in vitro study on the influence of laser-activated irrigation on infiltration and leakage of a dual curing-resin cement as an endodontic sealer.

The study aims to investigate the effects of laser-activated irrigation on infiltration and microleakage of a dual-curing resin cement applied as a root canal sealer. Thirty-eight extracted upper molars were attributed to four experimental groups. Roots were mechanically enlarged and disinfected (NaOCl). Control samples (n = 11) were irrigated with conventional needles and three different lasers were used to activate the irrigant in the other groups (n = 9): 2.94 µm Er:YAG laser, 9,300 µm CO2 laser and 808 nm diode laser with a modified black coated laser tip. Final irrigation was performed in each group with ethylenediaminetetraacetic acid (EDTA), sodium hypochlorite (NaOCl) and sodium chloride (NaCl) activated with lasers and in the control without activation.Dentin tubules were then labeled with a red fluorophore (Rhodamine B) and the root canals were sealed with a dual-curing resin cement (Paracore). The cement fixed the dye on the sealed and infiltrated dentin parts. To remove the Rhodamine not fixed by the cement, roots were then sectioned horizontally and immersed in hydrogen peroxide (H2O2). The empty dentin tubules spaces were then labeled with a green fluorophore (Fluorescein) allowing the visualization of infiltration and microleakage by confocal microscopy. Percentages of infiltration were significantly higher in the middle root third of the control and Er:YAG laser-activated samples compared to CO2 or diode laser groups. Microleakage was present in all experimental groups but significantly less after CO2 laser activation. Laser-activated irrigation impacted resin cement infiltration and microleakage dependent on the applied wavelength. Er:YAG laser activation led to higher values of infiltration and microleakage compared to CO2 and diode lasers.

Evaluation the stress distribution in root canals by 3D finite element analysis after the materials used in reattaching the vertically root fractured fragments.

The aim was to evaluate the effect of stress distribution on vertical, horizontal, and oblique forces on the tooth model after reattaching the fragments of the maxillary incisor with vertical root fracture (VRF) using different materials, by 3D finite element analysis (FEA). Tooth with a root canal, spongious, and cortical bone models were designed. VRF was modeled on a tooth with 4 different re-attachment models: Group 1: dual-cure cement (DC)+fiber reinforced composite (FRC), Group 2: DC+polyethylene fiber, Group 3: DC+glass fiber, and Group 4:DC. 100 N force was applied in 3 different directions. Maximum principal stresses (σmax) of dentin, and re-attachment materials were evaluated on colored images. The highest σmax values ​​were on the repair materials under vertical forces for Groups 1 and 4, respectively; Groups 2 and 3 showed similarity. The highest σmax values in repair materials under horizontal and oblique forces were observed in Group 3 however the lowest σmax values in repair materials under oblique and horizontal forces were observed in Group 1. The stress values ​​on repair materials gradually increased respectively starting from horizontal to vertical. As the elasticity modulus of the repair materials increased, the stress values ​​on root dentin increased. Through all force directions, except vertical forces, lower stress values were observed with FRC. The fracture resistance was bigger when using solely FRC or dual-cure resin cement in comparison to fiber-supported designs. Adding polyethylene fiber to re-restorations decreased stress values ​​compared to glass fiber addition. Therefore, when adding fibers, polyethylene fiber will be advantageous.

Effect of diode laser irradiation on bond strength of resin cements to high-translucent zirconia.

Treatment of acid-resistance high-translucent zirconia prior to luting procedures is usually carried out with sandblasting. Considering that this process could lead to the formation of cracks on the zirconia surface, laser irradiation became an alternative to sandblasting. The effect of diode laser, however, was never investigated under this context. Therefore, this study aimed to evaluate the effect diode laser irradiation on the bond strength between zirconia and two resin cements after 48-hour and 12-month water aging. Slabs of high-translucent zirconia were sandblasted with 50-µm Al2O3 particles (SB), irradiated with diode laser (DL), or SB+DL. All slabs were etched with 10% hydrofluoric acid and layered with a universal adhesive. Plastic tubes with 0.8-mm internal diameter positioned on treated zirconia surfaces were used as matrices to insert a dual- (DUAL) or a light-cure (LC) resin cement. All specimens were light-cured for 40 seconds at 1000 mW/cm2 and submitted to the µSBS test after 48-hour or 12-month water storage. Data were statistically analyzed with a three-way analysis of variance (p<0.05). The µSBS of DUAL was higher than LC only after 12 months for SB or SB+DL-treated zirconia (p<0.05); in addition, SB+DL resulted in higher µSBS than DL only for DUAL resin cement (p<0.05). The 12-month aging resulted in higher µSBS for DUAL resin cement luted on SB or SB+DL-treated zirconia, as well as for LC luted on DL-treated zirconia (p<0.05). Most of the DUAL specimens presented adhesive failures after 48 hours. After 12 months, the majority of DUAL specimens luted on DL or SB+DL-treated zirconia presented adhesive failures. The use of dual-cure resin cement on sandblasted or sandblasted and diode laser-irradiated zirconia exhibited superior bond strength after aging. Key words:Microshear bond strength, Resin cement, Diode laser, Zirconia, Sandblasting.

Effects of a relined fiberglass post with conventional and self-adhesive resin cement.

This study was conducted to evaluate the mechanical properties of relined and non-relined fiberglass posts when cemented to root canal dentin using a conventional dual-cure resin cement or a self-adhesive resin cement. Two types of resin cements were utilized: conventional and self-adhesive. Additionally, 2 cementation protocols were employed, involving relined and non-relined fiberglass posts. In total, 72 bovine incisors were cemented and subjected to push-out bond strength testing (n = 10) followed by failure mode analysis. The cross-sectional microhardness (n = 5) was assessed along the root canal, and interface analyses (n = 3) were conducted using scanning electron microscopy (SEM). Data from the push-out bond strength and cross-sectional microhardness tests were analyzed via 3-way analysis of variance and the Bonferroni post-hoc test (α = 0.05). For non-relined fiberglass posts, conventional resin cement exhibited higher push-out bond strength than self-adhesive cement. Relined fiberglass posts yielded comparable results between the resin cements. Type II failure was the most common failure mode for both resin cements, regardless of cementation protocol. The use of relined fiberglass posts improved the cross-sectional microhardness values for both cements. SEM images revealed voids and bubbles in the incisors with non-relined fiberglass posts. Mechanical properties were impacted by the cementation protocol. Relined fiberglass posts presented the highest push-out bond strength and cross-sectional microhardness values, regardless of the resin cement used (conventional dual-cure or self-adhesive). Conversely, for non-relined fiberglass posts, the conventional dual-cure resin cement yielded superior results to the self-adhesive resin cement.

In Vitro Investigation of Shear Bond Strength of Titanium Alloy Bonded to Monolithic Zirconia Prepared Via Different Surface Roughening Methods Using Different Cements

Objective: To evaluate the shear bond strength (SBS) of yttrium-stabilized tetragonal zirconia polycrystals bonded to titanium alloys via different surface treatment methods using four different cements.&#x0D; Methods: Eighty titanium and monolithic zirconia discs were prepared with computer-aided design/manufacturing (CAD/CAM) technology. All titanium discs and 40 of monolithic zirconia discs were polished by using silicon carbide paper and sandblasted with 50 μm aluminum oxide (Al2O3). Tribochemical silica coating was applied to remaining 40 monolithic zirconia discs. The monolithic zirconia discs were divided into eight groups after surface treatment (n=10). Titanium discs were cemented using conventional glass ionomer cement (GIC), resin-modified GIC, self- adhesive resin cement, and dual-cure resin cement. The SBS test was performed using a universal testing machine. The failure patterns were examined by using a scanning electron microscope (SEM). Data were statistically analyzed with one-way analysis of variance (ANOVA), two-way ANOVA and Tukey’s test (α

Light transmittance through resin-matrix composite onlays adhered to resin-matrix cements or flowable composites

ObjectiveThe aim of this study was to evaluate the influence of the thickness of resin-matrix composite blocks manufactured by CAD-CAM on the light transmittance towards different resin-matrix cements or flowable composites. MethodsSixty specimens of resin-matrix composite CAD-CAM blocks reinforced with 89 wt% inorganic fillers were cross-sectioned with 2 or 3 mm thicknesses. The specimens were conditioned with adhesive system and divided in groups according to the luting material, namely: two dual-cured resin-matrix cements, two traditional flowable resin-matrix composites, and one thermal-induced flowable resin-matrix composite. Specimens were light-cured at 900 mW/cm2 for 40s. Light transmittance assays were preformed using a spectrophotometer with an integrated monochromator before and after light-curing. Microstructural analysis was performed by optical and scanning electron microscopy (SEM). Nanoindentation tests were performed to evaluate mechanical properties for indirect evaluation of degree of monomers conversion. ResultsOptical and SEM images revealed low thickness values for the cementation interfaces for the traditional flowable resin-matrix composite. The cement thickness increased with the size and content of inorganic fillers. The highest light transmittance was recorded for the onlay blocks cemented with the traditional flowable resin-matrix composites while a group cemented with the dual-cured resin-matrix cement revealed the lowest light transmittance. The elastic modulus and hardness increased for specimens with high content of inorganic fillers as well as it increased in function of the light transmittance. ConclusionsThe light transmittance of flowable resin-matrix composites was higher than that for resin-matrix cement after cementation to resin-matrix composites blocks. The type, size, and content of inorganic fillers of the luting material affected the thickness of the cement layer and light transmittance through the materials. Clinical relevanceOn chair-side light curing, the transmission of visible light can be interfered by the chemical composition and viscosity of the luting materials. The increase in size and content of inorganic fillers of resin-matrix composites and luting materials can decrease the light transmittance leading to inefficient polymerization.

The effect of touch-cure polymerization on the push-out bond strength of fiber posts

ObjectiveTo assess the impact of a novel touch-cure polymerization of dual-curing resin cement on the push-out bonding strength (PBS) of the conventional prefabricated glass fiber-reinforced composite (GFRC) and custom-made glass fiber (GF) posts at different root sections. MethodsForty single-root mandibular first premolars were treated endodontically and prepared for receiving the posts, the prepared roots were randomly divided into 4 groups. Group I: A prefabricated (GFRC) post was cemented by G-CEM ONE resin cement with adhesive-enhancing primer (AEP). Group II: A prefabricated (GFRC) post was cemented by G-CEM ONE without AEP. Group III: A customized (GF) post was cemented by G-CEM ONE with AEP. Group IV: A customized (GF) post was cemented by G-CEM ONE without AEP. (n = 10 for each group). The PBS was tested with a universal testing machine, and the values were analyzed with (ANOVA) and Tukey’s post hoc test at a P ≤ 0.05 significance level. ResultsGroup III revealed the greatest PBS values, followed by Group IV, Group I, and finally, Group II showed the lowest PBS values. The coronal root slices showed the highest PBS in comparison with the middle and apical third. ConclusionThe touch-cure polymerization improved the PBS of the prefabricated and customized fiber posts. Therefore, ‟touch and cure” cement may be considered a clinical alternative to conventional types of resin cement. The customized (GF) posts exhibited a higher PBS than the prefabricated (GFRC). The combination of customized posts and G-CEM ONE with AEP is recommended as a new strategic approach to improve interfacial adhesion.

Evaluation of Sealer Remnants Using a Bioceramic Sealer Single-cone Technique after Post Space Preparation and its Influence on the Adhesion of Fibre Posts in vitro.

To compare calcium silicate-based endodontic sealer and epoxy resin-based sealer remnants on root canal walls after post space preparation and their influence on the bond strength of fibre posts fixed with a dual-cured resin cement. Thirty-six extracted single-root mandibular premolars were instrumented and divided randomly into two equal groups with different endodontic sealers. iRoot SP (Innovative BioCeramix, Vancouver, Canada) was employed in the experimental group and AH Plus (Dentsply Sirona, Charlotte, NC, USA) was used in the control group. Sealer remnants were observed under an endodontic microscope after root canal therapy and post space preparation. Fibre posts were fixed with dual-cured resin cement. Specimens were taken at each third of the post space. The push-out bond strength was measured using a universal testing machine and fracture modes were assessed. Statistical analysis was performed using an independent samples t test and one-way analysis of variance. There was no statistically significant difference in bond strength of fibre posts between the control and experimental group (P > 0.05); however, sealer remnants were observed in 38.9% of the samples treated with iRoot SP and none of the samples treated with AH Plus. The major fracture mode in samples treated with iRoot SP was adhesive failure between the resin cement and the post, and no adhesive failure between the resin cement and dentine occurred at the site of the sealer remnant. The presence of iRoot SP remnants on the root canal walls after post space preparation did not interfere with bonding. iRoot SP is a viable option for root canal obturation before fibre post cementation.

In vitro shear bond strength over zirconia and titanium alloy and degree of conversion of extraoral compared to intraoral self-adhesive resin cements

ObjectiveEvaluation of the Shear bond strength over zirconia and titanium alloy and degree of conversion of extraoral compared to intraoral self-adhesive resin cements.Materials and methodsNine bonding protocols were carried out on zirconia 4Y-TZP and titanium alloy (Ti-6Al-4V). Seven resin cement (one extraoral and six intraoral) were tested in the shear bond strength test and the degree of conversion measurements.ResultsThe significantly highest value was obtained for Monobond Plus + Multilink Hybrid Abutment, the extraoral resin cement for both titanium alloy (35.1 MPa) and zirconia (32.9 MPa). For each resin, significantly higher DC values were obtained for the dual-cure mode compared with the self-cure mode. Regardless of the cure mode, Nexus Universal reached the highest DC (78.4%).Discussion/ConclusionsIn this study, the extraoral self-curing resin cement showed the higher bond strength values on zirconia and titanium alloy when associated with a universal primer. Some intraoral dual-cure resin cements showed closed performances when used with universal primers. There is no direct correlation between the degree of conversion of the resin cement and the shear bond strength obtained on the prosthetic materials tested.

Pretreatment of Hybrid Ceramics Using Alumina (Al2O3) Nanoparticles, Hydrofluoric Acid, and Holmium: YAG Laser for Optimizing Surface Roughness, Shear Bond Strength, and Topography

Evaluation of different conditioning regimes i.e., hydrofluoric acid (HFA), sandblasting (SB), selfetching ceramic primer (SECP), and Holmium: YAG (Ho: YAG) laser on the surface roughness (Ra) and shear bond strength (SBS) of hybrid ceramics. One hundred and ten hybrid ceramic discs were fabricated using the CAD-CAM technique. The discs were randomly allocated into five groups. Group 1: No Conditioning (Control), Group 2: HFA etching, Group 3: SB, Group 4: SECP and Group 5: Ho: YAG laser. The quantitative measurement of the roughness (Ra) (n = 10) from each group was conducted using a profilometer. The dual cure resin cement was bonded on the remaining fifty samples. Shear bond strength (SBS) and failure analysis were performed using a universal testing machine (UTM) and stereomicroscope. One-way analysis of variance (ANOVA) with post hoc Tukey tests was used to assess and compare the mean values of Ra and SBS among study groups. Specimens pretreated with SB displayed the maximum Ra value and bond scores. The control specimens exhibited minimum Ra and SBS. Intergroup comparison analysis indicated that HFA and Ho: YAG laser-treated groups displayed comparable outcomes of Ra and bond integrity. Sandblasting using alumina particles proved to be the most favorable pretreatment modality for hybrid ceramic surface pretreatment for attaining optimum surface roughness and shear bond strength.

Assessment of physical/mechanical properties and cytotoxicity of dual-cured resin cements containing Sr-bioactive glass nanoparticles and calcium phosphate.

The aim was to develop dual-cured resin cements containing Sr-bioactive glass nanoparticles (Sr-BGNPs; 5 or 10 wt%) and monocalcium phosphate monohydrate (MCPM; 3 or 6 wt%). Effects of additives on degree of monomer conversion (DC), biaxial flexural strength/modulus, shear bond strength (SBS), mass/volume change, color stability, ion release, and cytotoxicity were examined. Controls included material without reactive fillers and Panavia SA Plus (PV). Experimental cements showed higher DC than PV regardless of light activation (p<0.05). Mean SBS and color stability were comparable between experimental cements and PV. Cell viability upon the exposure to sample extracts of experimental cements was 80%-92%. High additive concentrations led to lower strength and modulus than PV (p<0.05). The additives increased mass change, reduced color stability, and promoted ion release. The experimental resin cements demonstrated acceptable mechanical/chemical properties and cytotoxicity. The additives reduced the strength but provided ion release, a desirable action to prevent recurrent caries.

Evaluating the use of self-conditioning adhesive combined with dual curing resin cement as an endodontic sealer: An in vitro study.

Objectives To compare infiltration, sealing and microleakage in root dentin with a self-conditioning adhesive system combined with dual curing resin (resin-based cement) to a conventional epoxy-resin-based sealer using confocal microscopy imaging. Methods 26 roots were enlarged and disinfected. Dentin tubules of 24 teeth were labelled with a red fluorophore (Rhodamine B) (two samples served as controls). Root canal samples were sealed in group AH (n = 11) with a conventional sealer (AH Plus Root Canal Sealer, Dentsply DeTrey) and in group RC (n = 11) with a resin-based cement (Parabond combined with Paracore, Coltène). Roots were then sectioned horizontally and immersed in H2O2 to remove the Rhodamine B not fixed by the sealers. The empty dentin spaces were labeled with a green fluorophore (Fluorescein) enabling the evaluation of infiltration as well as microleakage by confocal microscopy. Two additional samples were fractured in vertical direction for observation under SEM. Results Group RC presented significantly more infiltration in the middle third than in the middle and apical thirds of group AH. Microleakage was significantly higher in group AH than in group RC. SEM images revealed more dentin plugs and a homogenous resin layer in group RC in contrast to group AH. Conclusion The resin-based cement revealed promising outcomes compared to a traditional epoxy resin based sealer.