Composite Resin Cement Research Articles

Comparison of shear bond strength of composite resin, compomer, and resin-modified glass-ionomer cements in primary teeth: An in-vitro study.

The contemporary esthetic restorative materials such as composite resin and glass-ionomer cements and their modifications have all been developed keeping in mind the requirements of permanent teeth. There have been plenty of studies that have focused on the characteristics of these materials in relation to permanent teeth with a relative dearth of such studies as regard to the primary teeth. The present study was undertaken to compare and evaluate the shear bond strength of composite resin, compomer, and resin-modified glass-ionomer cements in primary teeth. Thirty non-carious primary molars that were indicated for extraction because of physiological resorption or, for orthodontic reasons, were selected. The selected teeth were randomly allocated to three groups of 10 each for composite, compomer, and resin-modified glass-ionomer cements. The enamel from the occlusal surface of all teeth was removed to expose the superficial dentin and was wet polished with 400 grit sand paper. Composite, compomer, and resin-modified glass-ionomer stubs were bonded on to the occlusal surfaces using a plastic tube as a template. All samples were, then, subjected to thermocycling and evaluation of shear bond strength using the universal testing machine at a cross-head speed of 0.5 mm/min, whereas the results obtained were subjected to statistical analysis. Statistical analysis was performed using Statistical Package for Social Sciences (SPSS) version 17.0 (SPSS Inc., Chicago, IL, USA), whereas one-way analysis of variance (ANOVA) and Tukey's multiple post-hoc procedures were used for statistical analysis. A P < 0.05 was considered statistically significant. The mean shear bond strength values for Groups I, II, and III were found to be 11.7 ± 3.07 MPa, 7.74 ± 4.16 Mpa, and 4.43 ± 2.08 Mpa, respectively, whereas one-way ANOVA and Tukey's multiple post-hoc procedures indicated that there were remarkable differences among the three groups with the results being statistically significant (P < 0.05). Composite resin showed the highest shear bond strength in relation to primary dentin when compared to compomer and resin-modified glass-ionomer cements.

The effect of mechanical and chemo-mechanical temporary cement cleaning methods on shear bond strength with self-adhesive resin cement (an in-vitro study)

BackgroundAdhesive tooth-colored restorations are strongly dependent on the substrate surface cleanliness to allow intimate contact between resin cement and dentin surface, so several methods were adopted for the total cleaning of temporary cement residues. This study aimed to assess the effect of mechanical and chemo-mechanical cleaning methods of temporary cement on the immediate shear bond strength of self-adhesive resin cement to dentin surface.MethodsForty freshly extracted lower first premolars were cut to expose a flat dentin surface. Discs of temporary crown composite resin material were constructed and cemented to the flat dentin surface using resin-based and non-eugenol temporary cement then stored at room temperature in distilled water. Dividing of samples into two groups according to the method of temporary cement cleaning. Group I (n = 20) mechanical cleaning using the rotary instrument, and group II (n = 20) chemo-mechanical cleaning using chlorhexidine-containing scrub. CAD/CAM reinforced Composite discs were bonded to the dentin surface using self-adhesive composite resin cement, then measurement of shear bond strength was done using a universal testing machine. Further analysis of failure mode after debonding was performed by Scanning electron microscope.ResultsNo statistically significant difference was found between the mean shear bond strength of the two cleaning methods (P-value = 0.636). Regardless of the cleaning method, the group cemented with resin-based temporary cement showed statistically significantly higher mean shear bond strength than non-eugenol temporary cement (P-value = 0.048).ConclusionBoth cleaning methods (mechanical and chemo-mechanical) applied in this study were effective in cleaning temporary cement remnants from the dentin substrate surface with statistically significant differences between results of shear bond strength with significantly higher values recorded with resin-based temporary cement.

Effect of preheating on the physicochemical properties and bond strength of composite resins utilized as dental cements: An in vitro study

Statement of problemLittle is known regarding the use of preheated composite resins to bond indirect restorations and its impact on mechanical properties when compared with resin cements. PurposeThe purpose of this in vitro study was to compare the chemical and physical properties and bond strength to enamel and ceramics of preheated composite resins and resin cements. Material and methodsTwo composite resins, the microhybrid Filtek Z250XT and the nanoparticulate Z350XT were tested, and 2 commercially available resin cements, the dual-polymerized Rely-X ARC and the light-polymerized Rely-X Veneer were used as controls. A device (HotSet) was used to preheat the composite resins to 69 °C before light-polymerization. The following properties were tested: flexural strength, modulus of elasticity, fracture toughness, microshear bond strength to enamel and ceramics, degree of conversion, flow, sorption and solubility, and color stability. Statistical analysis was done with ANOVA and Holm-Sidak for multiple comparisons (α=.05). ResultsPreheating had no significant effect on the degree of conversion, flexural strength, fracture toughness, solubility, or microshear bond strength to the enamel of the tested composite resins (P>.05). However, preheating increased the sorption and reduced the microshear bond strength to the ceramic (P<.05). The flowability of the composite resins increased with heating but showed lower values when compared with both resin cements (P<.05). Color stability was more affected in the preheated composite resins than in the resin cements. ConclusionsThe preheating process resulted in little to no benefit in the evaluated properties for the composite resins. Resin cements appear to be the best option for cementing indirect restorations.

Comparative Evaluation of Microtensile Bond Strength in Three Different Dentin Luting Agents: An In vitro Study.

Long-term clinical success on indirect restorations is largely determined by bonding efficiency of the luting agent, with adhesion to dentin being the main challenge. Therefore, aim of this study was to assess the microtensile bond strength when using flowable resin composite, preheated resin composite and dual self-adhesive resin cement as dentin luting agents. Occlusal thirds of molar teeth were cut and randomly divided into 3 groups to be cemented: RelyX™U200, Filtek™ Z250 XT- preheated to 70° and Filtek Flow™ Z350XT. They were then thermocycled 5000 times between 5+/-2°C and 55+/-2°C. Subsequently, 10 microbars per group were prepared. The 30 samples were placed in saline solution for 24 hours at room temperature prior to microtensile test. This was performed with a digital universal testing machine at a crosshead speed of 0.5 mm/min. The bond strength values obtained were analyzed in Megapascals (MPa). Measures of central tendency such mean and measures of dispersion such standard deviation were used. In addition, the Kruskall Wallis non-parametric test with Bonferroni post hoc test was applied, considering a significance value of 5% (P < 0.05), with type I error. The dentin microtensile bond strengths of preheated resin composite, flowable resin composite and dual self-adhesive cement were 6.08 ± 0.66 Mpa, 5.25 ± 2.60Mpa and 2.82 ± 1.26Mpa, respectively. In addition, the preheated resin composite exhibited significantly higher microtensile bond strength compared to the dual self-adhesive cement (P < 0.001). While the flowable resin composite showed no significant difference with the dual self-adhesive cement (P = 0.054) and the preheated resin composite (P = 0.329). The microtensile bond strength in dentin was significantly higher when using a preheated resin composite at 70°C as a luting agent compared to dual self-adhesive cement. However, the preheated resin composite showed similar microtensile bond strength compared to the flowable resin composite.

Do preheated composite resin or adhesive resin layer strengthen the feldspar ceramic?

Statement of problemPreheated composite resin and adhesive coating have been recommended as luting agents for ceramic veneers; however, information about the mechanical behavior of feldspathic porcelain veneers after using these methods is still limited. PurposeThe purpose of this in vitro study was to evaluate the influence of the use of preheated composite resin or an adhesive resin layer on the strengthening of a feldspathic porcelain. Material and methodsFeldspathic porcelain disks were fabricated (N=210), etched (10% hydrofluoric acid for 90 seconds), and bonded according to resin-based luting agents (30 per group) for the biaxial flexural strength tests: photopolymerized resin cement, flowable composite resin, preheated composite resin, with or without previous adhesive coating. Characteristic strength and Weibull modulus were calculated. The viscosity of the luting agents was measured by using isothermal analyses. Finite element analysis simulated the flexural test. Fractographic and bonded interfaces were observed. ResultsThe use of preheated composite resin led to the lowest stress levels in the feldspathic porcelain veneers. However, it did not increase the ceramic strengthening compared with other luting agents, as higher values were observed with flowable composite resin (P<.05). The use of an adhesive resin layer had no significant effect on ceramic strengthening when associated with preheated composite resin or resin cement (P>.05). Preheated composite resin presented the highest viscosity and led to incomplete filling of the porcelain surface irregularities. Failures originated on the ceramic surface subjected to tensile stress and were typically associated with pores at the ceramic-luting agent interface. ConclusionsThe use of preheated composite resin or an adhesive resin layer did not have a positive effect on strengthening feldspathic porcelain.

COMPARISON OF SHEAR STRENGTH CEMENTATION OF PREHEATED RESIN COMPOSITE AND RESIN CEMENT ON INDIRECT LITHIUM DISILICATE

Background: The success of fixed dentures is influenced by the cementation procedure. Resin cement is the most commonly used luting materials. In addition to resin cement, there are other types of luting materials, preheated resin composite. Preheating resin composite allow the material to have a low level of viscosity, therefore can be used as luting material. The purpose of this study was to evaluate the comparison of the shear strength cementation of preheated resin composite and resin cement on indirect lithium disilicate. Method: This study is experimental laboratory with post test only control group design. The sample in this study are 12 pieces lithium disilicate with diameter 5.5 mm x 3 mm cemented divided into three groups based on types of luting materials (preheated resin composite microhybrid, preheated nanohybrid, and resin cement). After the cementation procedure, the samples were immersed in artificial saliva at 37ºC for 24 hours. The shear strength test was carried out with a universal testing machine. Data analysis with using One Way ANOVA. Result: The results of the average shear strength of each group were 11.98 MPa for preheated microhybrid, 11.41 MPa for preheated nanohybrid, and 14.22 MPa for resin cement. The results of the One Way ANOVA test showed that there was a significant differences between groups (p value 0.000). Conclusion: There was a significant difference in shear strength between preheated microhybrid, preheated nanohybrid, and resin cement. The highest shear strength was the resin cement group.

Effect of Ozone on Bond Strength of Different Restorative Materials to Enamel and Dentin

ABSTRACT The aim of this study is to examine the effects of ozone treatment applied at two different times, followed by the in vitro application of a reductant solution, on the shear bond strength of four different restorative materials to enamel and dentin. A total of 400 caries-free human molar teeth were randomly divided into enamel and dentin groups, and each was divided into five subgroups. The O20 group received 20-s ozone, O20 + R received 20-s ozone+reductant solution, O80 received 80-s ozone, O80 + R received 80-s ozone+reductant solution, and C was the control group. Each subgroup was then divided into four more subgroups based on restorative material (i.e., nanohybrid resin composite, silorane-based microhybrid resin composite, compomer, or conventional capsulated glass ionomer cement). After water storage for seven days, shear bond-strength data (MPa) were measured using a universal testing machine at a crosshead speed of 0.5 mm/min until fracture, and failure types were examined. The effects of ozone and ozone+reductant applications on enamel and dentin were examined via scanning electron microscopy (SEM). Bond strength data were statistically evaluated using a three-way analysis of variance and Tukey’s honestly significant difference test (a = 0.05). The bond strength of the control group was like that of the O20 group (p > 0.05), but it was higher than all other groups regardless of the type of restorative material or tooth structure (p < 0.05). Adhesive-type failures were found in most groups. Via SEM examinations, it was observed that ozone applications did not change the enamel morphology, but they did cause narrowing of the dentinal tubule openings in O80 + R.

Dental trauma simulation training using four splinting models: A cross sectional study.

Opportunities for dental students to obtain clinical experience in the management of traumatic dental injuries are scarce, and most dentists encounter difficulties with their first trauma patients after graduation. The aim of this study was to question students on the ease of handling of four types of flexible splints, with two common methods of bonding to the tooth. A total of 161 fourth year dental students completed a simulated treatment of an avulsed tooth using orthodontic wire, Twistflex wire, nylon fishing line, and Powermesh as splints. The bonding materials were composite resin (Spectra ST LV) or glass ionomer cement (GC Fuji LC Ortho). The students then answered 16 questions on a 5-point Likert scale, or with an open answer field. Most students agreed (48.8%) or strongly agreed (31.3%) that the simulated trauma exercise assisted their learning. There was strong agreement (68.8%) and agreement (28.7%) that the simulation added value to their dental training compared to didactic training only. Similarly, 52.3% of participants strongly agreed and 40% agreed that they felt engaged in the learning activity. Only 53.8% of the participants agreed and 7.5% strongly agreed that the simulation felt realistic. Most students (56.2%) found a Powermesh/composite splint was the easiest to place, and nylon fishing line/GC Fuji LC Ortho splints was the least difficult to remove (35%). Wire-free splints with composite bonding were judged as the easiest to place by students, while glass ionomer cement was the easiest to remove.

Fatigue and failure analysis of restored endodontically treated maxillary incisors without a dowel or ferrule

Statement of problemInformation on the survival and mode of failure of endodontically treated incisors without a ferrule and restored without dowels is lacking. PurposeThe purpose of this in vitro study was to compare the survival and failure mode of endodontically treated incisors without a ferrule and restored with bonded ceramic crowns and various composite resin foundation restorations without dowels with a control group with fiber dowels. Material and methodsForty-five decoronated endodontically treated bovine incisors without ferrule were divided into 3 experimental groups and restored with different adhesive foundation restorations without dowel: nanohybrid composite resin (Nd), bulk-fill composite resin foundation restoration (NdB), and fiber-reinforced bulk-fill composite resin (NdFR). A control group with conventional foundation restorations (glass-fiber dowel with nanohybrid composite resin foundation restoration without ferrule) (D) was included for comparison. All teeth were prepared to receive bonded lithium disilicate ceramic crowns luted with dual-polymerizing composite resin cement and were subjected to accelerated fatigue testing. Cyclic isometric loading was applied to the incisal edge at an angle of 30 degrees and a frequency of 5 Hz, beginning with a load of 100 N (5000 cycles). A 100-N load increase was applied each 15 000 cycles. Specimens were loaded until failure or to a maximum for cycles endured of 1000 N (140 000 cycles). Groups were compared by using the Kaplan-Meier survival analysis (log rank test at α=.05 and pairwise post hoc comparisons) and life table analysis for load-at-failure (followed by Wilcoxon pairwise comparison α=.05). ResultsAll the specimens failed before 140 000 load cycles. Even though no statistically significant differences were found between the experimental groups without dowel (P>.127), the fiber-reinforced foundation restoration yielded the highest mean ±standard deviation cycles to failure (46 023 ±4326) compared with Nd (38 899 ±2975) and NdB (39 751 ±2998). NdFR, however, outperformed the foundation restoration with glass-fiber dowel (35 026 ±2687) (P<.05). Most failure in groups without dowel were restorable, while 100% of catastrophic failure (unrestorable) were found in the group with dowels. ConclusionsBased on the present in vitro study, dowels did not improve the performance of the adhesive restoration of endodontically treated incisors without a ferrule. The use of a short fiber-reinforced composite resin foundation restoration without a dowel was able to not only improve the resistance of the restorations compared with adhesive foundation restorations with dowels but also minimize catastrophic failures.

Influence of surface treatment and curing mode of resin composite cements on fibroblast behavior

BackgroundHuman gingival fibroblast (HGF-1) cells in the connective tissue provide an effective barrier between the alveolar bone and the oral environment. Cement margins of restorations with intrasulcular preparation or cemented implant restorations are in contact with HGF cells. However, it is unknown to what extend the cement surface finish affects the behavior of HGF cells. The purpose of this study was to compare the behavior of HGF-1 cells in contact with two different resin composite cements with three different surface treatments after light-curing and autopolymerization, respectively.MethodsDisks of one adhesive (Multilink Automix, Ivoclar Vivadent [MLA]) and one self-adhesive (RelyX Unicem 2 Automix, 3 M [RUN]) resin composite cement were either light-cured or autopolymerized. Specimen surfaces were prepared with the oxygen inhibition layer intact, polished with P2500-grit silicon carbide paper or treated with a scaler. Cells were cultivated on the specimens for 24 h. Viability assay was performed, and cell morphology was examined with scanning electron microscopy. Additionally, roughness parameters of the specimen were analyzed with a 3D laser scanning microscope. Three-way ANOVA was applied to determine the effect of cement material, curing mode and surface treatment (a = 0.05).ResultsOverall, cement material (p = 0.031), curing mode (p = 0.001), and surface treatment (p < 0.001) significantly affected relative cell viability of HGF. The autopolymerized specimen with the oxygen inhibition layer left intact displayed the lowest relative cell viability (MLA 25.7%, RUN 46.6%). Removal of the oxygen inhibition layer with a scaler increased cell viability but also resulted in higher surface roughness values.ConclusionsHGF cell viability is affected by the surface treatment and the curing mode. The oxygen inhibition layer is an inhibitory factor for the viability of HGF cells. Autopolymerization enhances the cytotoxic potential of the oxygen inhibition layer.

Which Zirconia Surface-cleaning Strategy Improves Adhesion of Resin Composite Cement after Saliva Contamination? A Systematic Review and Meta-Analysis.

To identify the most effective cleaning method for saliva-contaminated zirconia surface before adhesive cementation through a systematic review and meta-analysis. PubMed, Scopus, and Web of Science databases were searched to select in vitro studies published through October 2021. Studies that did not perform aging methods, had a sample size less than 5 per group, or did not present a group with zirconia contaminated only with saliva were excluded. Data were extracted and risk of bias was assessed. Statistical analysis comparing the cleaning methods was conducted, and the standardized mean difference was assessed using the R software program. Among 804 potentially eligible studies, 36 were selected for full-text reading, of which 13 were included in qualitative analysis, and 11 of these were subsequently included in the quantitative analysis. A meta-analysis revealed a significant difference in the bond strength between the cleaning methods. Sandblasting with Al2O3  showed a higher bond strength than cleaning solution (Ivoclean, Ivoclar Vivadent) (p < 0.01, I2 = 65%), and both methods promoted higher resin-bond strength to zirconia than water cleaning. In addition, there was no significant difference in the bond strength between alcohol (p = 0.35, I2 = 79%), phosphoric acid (p < 0.23, I2 = 90%), and water cleaning. Sandblasting with Al2O3 seems to be the best method for zirconia surface cleaning before adhesive luting, promoting better resin-bond strength to zirconia.

Mechanical Behavior of Alkasite Posterior Restorations in Comparison to Polymeric Materials: A 3D-FEA Study.

The present investigation evaluated the effect of the combination of different dental filling materials in Class I cavities under occlusal loading using three-dimensional finite elements analysis (FEA). Six computer-generated and restored models of a lower molar were created in the CAD software and compared according to the biomechanical response during chewing load condition. Two adhesively bonded bulk restorative materials [bulk-fill resin composite (BF) or Alkasite (Alk)] were evaluated with or without the presence of a base material below (flowable resin composite or glass ionomer cement). A food bolus was placed on the occlusal surface mimicking the compressive occlusal load (600 N) during the static linear analysis. The maximum principal stress (tensile) was calculated as stress criteria in enamel, dentin and restoration. All models showed high stresses along the enamel/restoration margin with a similar stress trend for models restored with the same upper-layer material. Stress values up to 12.04 MPa (Alk) or up to 11.12 MPa (BF) were recorded at the enamel margins. The use of flexible polymeric or ionic base material in combination with bulk-fill resin composite or Alk did not reduce the stress magnitude in dentine and enamel. Class I cavities adhesively restored with bulk-fill resin composite showed lighter stress concentration as well as Alk. Therefore, adhesively bonded Alk restoration showed a promising mechanical behavior when used with different base materials or as a bulk restoration for posterior Class I cavity.

A comprehensive in vitro study on the performance of two different strategies to simplify adhesive bonding

ObjectiveThe purpose of this study is to compare the bonding performance and mechanical properties of two different resin composite cements using simplified adhesive bonding strategies.Materials and methodsShear bond strength of two resin composite cements (an adhesive cement: Panavia V5 [PV5] and a self‐adhesive cement: RelyX Universal [RUV]) to human enamel, dentin, and a variety of restorative materials (microfilled composite, composite, polymer‐infiltrated ceramic, feldspar ceramic, lithium disilicate and zirconia) was measured. Thermocycle aging was performed with selected material combinations.ResultsFor both cements, the highest shear bond strength to dentin was achieved when using a primer (PV5: 18.0 ± 4.2 MPa, RUV: 18.2 ± 3.3 MPa). Additional etching of dentin reduced bond strength for RUV (12.5 ± 4.9 MPa). On enamel, PV5 achieved the highest bond strength when the primer was used (18.0 ± 3.1 MPa), while for RUV etching of enamel and priming provided best results (21.2 ± 6.6 MPa). Shear bond strength of RUV to restorative materials was superior to PV5. Bonding to resin‐based materials was predominantly observed for RUV.ConclusionsWhile use of RUV with the selective‐etch technique is slightly more labor intensive than PV5, RUV (with its universal primer) displayed a high‐bonding potential to all tested restorative materials, especially to resin.Clinical significanceFor a strong adhesion to the tooth substrate, PV5 (with its tooth primer) is to be preferred because etching with phosphoric acid is not required. However, when using a wide range of varying restorative materials, RUV with its universal primer seems to be an adequate option.

A novel dual surface modification on titanium in dental use: Characterization and topography

This laboratory study aimed to compare, contrast, and evaluate the effect of a novel dual surface modification method on the adhesion strength of resin composite cement to titanium. C.p.‐2 grade titanium samples were silica‐coated, etched with HNO3(69vol %) or a blend of HCl (35vol %) and H3PO4 (85vol %), for 1 h at 80°C. Surface roughness was measured by surface roughness profilometry, topographic analysis by scanning electron microscopy (SEM), atomic force microscopy (AFM), and surface analyses by energy dispersive X‐ray spectroscopy (EDX), X‐ray photoelectron spectroscopy (XPS). Silanization of all specimens was carried out after SEM, EDX, and AFM analysis, before enclosed mold microshear bond strength testing (EM‐μSBS). Adhesion strengths were measured after artificial ageing: 1 day, 1 week, 4 weeks, and 8 weeks by EM‐μSBS testing and failure mode analysis by optical microscopy. Polished titanium was used as a control. The highest surface roughness was observed in titanium samples treated with silica‐coating + HCl‐H3PO4 etching. The elemental composition confirmed the presence of Ti, O, C, with Si and Al in samples treated with silica‐coating. A gradual decrease in EM‐μSBS values was observed in all titanium samples with adhesive and cohesive failure modes. The novel dual surface modification method applied in this study suggests that silica‐coating + HCl‐H3PO4etching strongly affects titanium surface topography and roughness. The presence of Si on silica‐coated surface modified titanium before silanization with an experimental silane has a positive effect on the EM‐μSBS of titanium samples treated with silica‐coating only or silica‐coating + HNO3 etching.

Surface Roughness and Bond Strength of Resin Composite to Additively Manufactured Zirconia with Different Porosities.

To investigate the bond strength of resin cement to additively manufactured (AM) zirconia with different porosities when compared to milled zirconia. A 12 × 5 mm disk virtual design file was used to fabricate a total of 48 disks divided into 4 groups: 3 groups were AM with different porosities including 0%-porosity (AMZ0 group), 20%-porosity (AMZ20 group), and 40%-porosity (AMZ40 group), and 1 milled zirconia (control or CNCZ group). The dimensions of all specimens were measured using a digital caliper. A 3D- confocal laser scanner was used to analyze surface morphology and measure the surface roughness (Sa), followed by SEM analysis. Tensile bond strength of composite resin cement to specimens was measured before and after aging procedures using a universal testing machine (n = 10). Failure modes were evaluated under a light microscope. Volumetric change data was analyzed using one-way ANOVA, and two-way ANOVA was used to compare bond strength values (α = 0.05). There was a significant difference in volumetric changes among the groups. The CNCZ group showed the least changes in diameter 0.027 ± 0.029 mm and thickness 0.030 ± 0.012 mm and AM zirconia with 40% porosity showed the most volumetric changes in diameter 5.237± 0.023mm. ANOVA test indicated an overall significant difference in surface roughness across all groups (F = 242.6, p < 0.001). The CNCZ group showed the highest mean Sa of 1.649± 0.240µm, followed by AMZ40 group with Sa of 0.830 ± 0.063µm, AMZ20 group with Sa of 0.780± 0.070 µm, and the AMZ0 group with Sa of 0.612 ± 0.063 µm. Two-way ANOVA showed significant difference in bond strength between the CNCZ group 12.109 ± 3.223 MPa and the AMZ0 group 8.629 ± 0.914 MPa, with significant pretest failures in specimens with porosities. Thermal cycling methods reduced the bond strength non-significantly in CNCZ group with no effect in the AMZ0 group. Milled zirconia had a higher surface roughness and bond strength to composite resin cement than AM zirconia, and porosities in AM zirconia decreased the bond strength with significant pretest failures.

Effects of ytterbium laser surface treatment on the bonding of two resin cements to zirconia

Monolithic zirconia crowns bonded to zirconia abutments have become more commonly used in the construction of cement-retained implant superstructures. The present study aimed to examine the effects of laser surface treatments on the bond strength of two resin cements to zirconia. Three types of surfaces were examined: untreated, alumina blasted, and ytterbium laser treated; and two types of resin cements: 4-META/MMA-TBB resin cement and composite resin cement. Half of the specimens were subjected to a thermocycling process. Subsequently, a shear bond test was carried out. In addition, surface roughness was measured for each surface type. The results showed that laser treatment increased zirconia surface roughness and that laser treatment significantly increased shear bond strength after the thermocycling of both cement types compared to no treatment. Our experimental results suggested that ytterbium laser surface treatment of zirconia increased the bond strength of resin cements.

Bonding ability of resin cements to different types of CAD/CAM composite blocks.

This study investigated the bonding performance of two different types of resin cements to computer-aided design/computer-aided manufacturing (CAD/CAM) composite blocks based on the shear bond strength (SBS) test. A silane-containing self-adhesive resin cement (Panavia SA Cement Universal) and resin luting cement (Block HC Cem) with a primer, were used. Specimens were fabricated from three different types of CAD/CAM composite blocks, and their surfaces were blasted with alumina. Resin cements were bonded to the specimens, and their SBSs were measured after 15 min, 24 h, and after being subjected to thermal cycling for 10,000 and 30,000 cycles. Three-way ANOVA for bond strength revealed that CAD/CAM composite block, resin cement and storage time significantly influenced the SBS values, and the three-way interactions between the evaluated factors, and all the interactions were significant. It was concluded that the bonding performance of resin cements to CAD/CAM composite blocks were material and storage period dependent.

An Overview of Maryland Bridges and their Clinical Applications

Resin bonded bridges are fixed prostheses that require little to no surgery and are held in place by composite resin cements. The "Maryland" bridge, which was made possible by the invention of the electrolytical etching method for nickel-chrome alloys, enabled the resin cement to undergo micromechanical adhesion to the metal surface. Their major advantage is that they require minimal, or at best, no tooth preparation. The preparation is usually kept within enamel which eliminates the need for local anesthesia during tooth preparation. When care is taken to maintain the margins of the Maryland bridges supragingivally, periodontal health is preserved. An additional advantage of the Maryland bridges is that in the event that a wing debonds, it is possible to rebond it after merely cleansing the wing and tooth. The most frequent issues with resin-bonded prostheses including debonding are cavities and three-tooth discoloration. There are two alternatives if a bridge debonds: rebonding or remaking. Replacing the bridge has been proven to have a greater success rate. During the assessment phase, any deleterious behaviors should be discovered, and the individual should be advised to stop doing things like biting their nails or pens. They offer an alternative to traditional bridgework10 or implants for restoring lost teeth, and because they typically don't require local anesthesia, individuals who are afraid of needles or don't want to undergo extensive surgery can have the operation. Maryland bridges are a choice in situations where there might not be enough bone or three-dimensional space for implant implantation. Patients also prefer smaller sessions because of the cost savings compared to traditional bridgework and implant-supported restorations. These prostheses should be considered as a restorative choice for short time periods and those desiring minimal chair time given complete patient evaluation and the application of appropriate therapeutic procedures.

Color Stability of Bioactive Restorative Materials After Immersion in Various Media.

ABSTRACTObjectives:The aim of this article is to assess the color stability of the bioactive restorative materials (Activa Bioactive, Beautifil II) compared with the conventional resin composite and resin-modified glass ionomer cement after immersion in different staining solutions overtime.Materials and Methods:This is an in-vitro study that investigated four different material groups: (1) bioactive composite (ACTIVA Bioactive-Restorative, Pulpdent, USA), (2) Giomer composite (Beautifil II, SHOFU Dental GmbH, Japan), (3) resin-modified glass ionomer cement (Fuji II, GC Corporation, Japan), and (4) resin composite (Filtek Z350XT, 3M ESPE, USA). One hundred samples (n=25 each group) were fabricated using a custom acrylic mold (1 mm thick × 10 mm diameter) and then immersed in five different staining solution groups: coffee, black tea, cola, mixed berry juice, and saline. Baseline (T0) shade of samples was recorded using two spectrophotometers: VITA Easyshade Digital Advance and a spectrophotometer. Then shade was recorded at the intervals of 7 (T1), 14 (T2), and 28 (T3) days of immersion. Measurements were obtained and then ΔE was calculated for each group at each time point. Three-way analysis of variance tests were used to test the interactions between different variables at the 0.05 significance level.Results:All specimens showed a significant color change (P<0.001), following 7, 14, and 28 days of storage. Activa Bioactive and Filtek Z350 showed the highest color stability overtime in different staining solutions, whereas Fuji II and Beautifil II showed the least color stability. The most significant color change was noticed in the coffee group and then in the mixed berry juice group.Conclusion:Resin-based restorative materials showed higher color stability than glass ionomer-based restorations. Both spectrophotometers gave comparable results for materials’ color stability.

The resin bond to high-translucent zirconia-A systematic review.

Several systematic literature reviews have assessed the scientific evidence on resin bonding protocols to conventional 3mol% ytrria-stabilized zirconia (3Y-TZP) ceramics. It has been widely discussed, however, that the differing composition and physical properties of new high-translucent zirconia generations (4Y-TZP and 5Y-TZP) may require alternative bonding materials and procedures. This paper reviewed in vitro studies on the success and durability of bonding protocols to high-translucent zirconia. A systematic search of PubMed and Cochrane Library for in vitro studies on bonding to new zirconia generations published until November 2020 was conducted and complemented by a manual search. Studies selected for review fulfilled the applied inclusion and exclusion criteria. The quality of the included studies was assessed with the Cochrane risk-of-bias tool for randomized trials. Of 629 screened articles, 18 were included in this review. They investigated different surface pretreatment methods, primers, resin cements, aging procedures, and bond strength test protocols. The limited number of the identified studies and the heterogeneity of the extracted data did not allow to conduct a meta-analysis. The available evidence suggests that resin bonding protocols successfully applied to conventional zirconia are also the most successful for high-translucent zirconia. Airborne particle abrasion and special phosphate monomer-containing primers or composite resin cements provide long-term durable resin bonds. Durable bonds can be established between high-translucent zirconia and resin cements. The bonding materials and procedures applied do not compromise their physical properties.