Resin Cement Research Articles

Influence of Thickness of Endocrown and Ceramic Translucency on The Degree of Conversion of Resin Cement (In Vitro Study)

Influence of Thickness of Endocrown and Ceramic Translucency on The Degree of Conversion of Resin Cement (In Vitro Study)

Comparative evaluation of dental integrity using three computer-aided design/computer-aided manufacturing customized post systems

Background Endodontically treated teeth (ETT) are considered structurally compromised due to significant changes in their biomechanics.The purpose of this in vitro study was to evaluate fracture resistance using three computer-aided design/computer-aided manufacturing (CAD/CAM) customized post systems. Methods Forty extracted intact maxillary central incisors were used in the study, and the teeth were endodontically treated and randomly divided into four equal groups (n = 10): control group without any post and accessed cavity was restored with direct composite restoration. Test groups were prepared for a post and restored according to the material type. The posts and cores were fabricated with computer-aided design/computer-aided manufacturing technology using titanium, vita enamic, and biological dentin materials. The posts were luted using self-adhesive resin cement, and then, zirconia crowns were fabricated, cemented, teeth in all groups were mounted to universal testing machine and subjected to compressive load in Newton at crosshead speed 0.5 mm/min. Results Control group exhibited the highest fracture resistance (727 ± 172.05) followed by biological dentin posts with mean value (712.29 ± 298.58) then group titanium posts with mean value (678.59 ± 132.83) and the least fracture resistance was for group vita enamic with mean value 331.84 ± 74.27. Regarding to fracture favorable it was significantly higher in vita post group than titanium post group (70% vs. 30%) and control group (70% vs. 10%) but it was significantly higher in biological dentin group than titanium group (80% vs. 70%). Conclusion According to type of material, teeth restored with the biological dentin posts showed highest fracture resistance followed by titanium posts, the least fracture resistance was vita enami posts.

Resin Cements in Dentistry

Even though the GIC has undergone many advances, its chemistry is fundamentally different from that of modern resin based composite direct filling products, which feature a silica or glass particle filled polymer matrix that enhances repair retention. When the restoration is etched or air abraded after the tooth has been conditioned with an adhesive resin and etched, retention becomes "micromechanical," ensuring the resin cement's high tensile strength. Cementation of the extraoral fabricated restoration is very important for the longevity of the restoration. The bond strength of resin cement to ceramic and fibre post is better than conventional cements. This article discusses about the various types of resin cements and there uses for luting indirect restorations such crowns, veneers, inlays, and onlays, etc.

Effect of thermomechanical loading on fracture resistance and failure mode of new pressable zirconia-reinforced lithium disilicate onlay restoration.

Insufficient information exists regarding the fracture resistance and failure pattern of newly developed zirconia-reinforced lithium disilicate (ZL, Vita Ambria) onlays. This in vitro study compared the fracture resistance of two types of onlays: monolithic lithium disilicate (LD) and monolithic ZL. Forty-eight ceramic onlay restorations were fabricated on epoxy dies using a maxillary first premolar model. The samples were divided into two main groups: LD and ZL. Half of each group was subjected to thermomechanical fatigue loading (TML) using a chewing simulator. All the samples were cemented with self-adhesive resin cement. Subsequently, they were loaded until failure in a universal testing machine, and the fracture patterns and resistance were recorded. Before TML, ZL demonstrated the highest statistically significant mean fracture resistance (499.76±34.14N) compared to LD (470.40±27.38N). After TML, ZL showed the highest non-statistically significant mean fracture resistance (429.27±131.42N), while LD's mean fracture resistance decreased (377.31±62.18N). Monolithic zirconia-reinforced onlays demonstrated higher fracture resistance and a more favorable failure mode compared to LD. However, the impact of thermomechanical aging resulted in reduced fracture resistance for both materials, with a notable preference observed for ZL.

Influence of screw channel angulation on reverse torque value and fracture resistance in monolithic zirconia restorations after thermomechanical cycling: an in-vitro study

BackgroundWhile the concept of angled screw channels has gained popularity, there remains a scarcity of research concerning the torque loss and fracture strength of monolithic zirconia restorations with various screw channel angulations when exposed to thermomechanical cycling. This in-vitro study aimed to evaluate the reverse torque value and fracture resistance of one-piece screw-retained hybrid monolithic zirconia restorations with angulated screw channels after thermomechanical cycling.MethodsOne-piece monolithic zirconia restorations, with angulated screw channels set at 0°, 15°, and 25° (n = 6 per angulation) were fabricated and bonded to titanium inserts using a dual-cure adhesive resin cement. These assemblies were then screwed to implant fixtures embedded in acrylic resin using an omnigrip screwdriver, and reverse torque values were recorded before and after thermomechanical cycles. Additionally, fracture modes were assessed subsequent to the application of compressive load. One-way ANOVA and Bonferroni post hoc test were used to compare the groups (α = 0.05).ResultsThe study groups were significantly different regarding the fracture resistance (P = 0.0015), but only insignificantly different in the mean percentage torque loss (P = 0.4400). Specifically, the fracture resistance of the 15° group was insignificantly higher compared to the 0° group (P = 0.9037), but significantly higher compared to the 25° group (P = 0.0051). Furthermore, the fracture resistance of the 0° group was significantly higher than that of the 25° group (P = 0.0114).ConclusionsOne-piece hybrid monolithic zirconia restorations with angulated screw channels can be considered an acceptable choice for angulated implants in esthetic areas, providing satisfactory fracture strength and torque loss.

Influence of oil well cement on the structure and properties of thermosetting resin cementing fluids

Oil well cement was added as an admixture to the waterborne epoxy resin cementing fluid to form a resin-cement slurry system, and its properties were discussed in depth. It was found that the mechanical properties of the resin cement stone were best when the dosage of oil well cement was 10%. And the measurements of X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) showed that the addition of oil well cement did not affect the curing properties of the epoxy resin, and the epoxy resin did not affect the hydration process of cement and its products. According to data from the mercury-in-pressure porosity (MIP) method and scanning electron microscopy (SEM), it was obtained that the polymer film formed after the curing of epoxy resin was connected between the hydration products or wrapped around the unhydrated cement particles, which results in a denser structure within the resin cement stone. Overall, this resin-cement slurry system has the potential to enhance cementing quality.

Comparative bonding performance of coronal dentin disks and CAD/CAM resin composite disks for biological restoration: The impact of resin-coating technique.

This study evaluated the bonding performance of coronal dentin disks, designed for biological restoration, and CAD/CAM resin composite disks when bonded to flat dentin surfaces using dual-cure resin cements, with and without a resin-coating (RC) technique. Three distinct groups were established within the non-RC group, each using one of the two types of resin cements in a self-adhesive mode: one-step self-etch adhesive (1-SEA) without light-cure, 1-SEA with light-cure, and a separate group using an alternate cement. Within the RC group, a subgroup was established for each cement. The microtensile bond strength (μTBS) of the disk-dentin beam was tested after 0 and 10,000 thermocycles in a 5°C/55°C. No significant μTBS difference was observed among the non-RC groups. However, when using RC, the μTBSs of coronal dentin disks significantly exceeded those of CAD/CAM resin composite disks. Thermocycle aging did not affect μTBS in any of the bonding methods, except in self-adhesive mode.

Push-Out Bond Strength of Glass Fiber Endodontic Posts with Different Diameters.

(1) Background: The retention of intraradicular posts is an important factor for the prognosis of endodontically treated teeth. The purpose of this study was to evaluate the push-out bond strength (PBS) of the posts relating to their diameter and region of the root. (2) Methods: A total of 40 premolar teeth (decoronated and root canal-filled) were divided into four groups (n = 10). After post-space preparation, different sizes (1.0, 1.2, 1.5, and 2.0 mm) of glass fiber posts were luted with resin cement into the root canals. After placement, 2 mm thick slices were cut from the roots according to their apical, middle, and coronal regions (n = 116). Push-out tests were carried out in a universal testing machine on each slice. A statistical evaluation of the data was applied. (3) Results: When comparing the diameter, the 2.0 mm posts had the highest PBS (111.99 ± 10.40 N), while the 1.0 mm posts had the lowest PBS (99.98 ± 8.05 N). Divided by the surface of the bonded area, the average PBS value was the highest for the 1.0 mm posts (18.20 ± 1.67 MPa) and the lowest for the 2.0 mm posts (12.08 ± 1.05 MPa). (4) Conclusions: Within the limitations of the study, when comparing the regions of the roots, no significant differences were found among the PBS values of the three regions (p = 0.219). When comparing the diameters, significant differences were shown between the PBS values of the four groups (p = 0.023 and p = 0.003, respectively).

Comparative evaluation of microleakage in glass hybrid resin, alkasite resin, and shock-absorbing rubber resin in primary molars– An in-vitro study

Background To evaluate and compare the microleakage of Glass hybrid resin (Equia Forte), Alkasite resin (Cention N), and Fluoride-releasing shock-absorbing rubber resin (Activa Bioactive) in Class V cavities of primary molars. Material and Methods Thirty freshly extracted human primary molar teeth with pre-shedding mobility were selected and a standard class V cavity was prepared on the buccal surfaces of all teeth. The teeth were divided into 3 groups of 10 samples each. The prepared cavities of all samples were restored with their corresponding restorative material. The teeth underwent thermocycling for 500 cycles and were then immersed in the toluidine dye solution. The depth of dye penetration scores between and within 3 groups was analyzed using the Kruskal Wallis One-way ANOVA test, followed by multiple comparisons with the Dunn-Bonferonni post hoc test. Results Cention N (alkasite resin) showed the least depth of dye penetration, which was highly statistically significant (p=0.000), followed by Activa Bioactive (Fluoride-releasing shock-absorbing rubber resin) and Equia Forte (Glass Hybrid resin). No samples showed depth involving the pulpal floor. Conclusion Cention N (alkasite resin) restorative material had the least microleakage and may be an excellent alternative material that provides a long-term clinical solution for the restoration of carious teeth with its improved marginal seal and reduced chances of microleakage. Clinical Significance Cention N may be an excellent alternative material that provides a long-term clinical solution for the restoration of carious teeth with its improved marginal seal and reduced chances of microleakage. Key Words: Activa Bioactive, Cention N, Equia forte, Microleakage, Resin cements

Effect of Dentin Irrigants on Push-Out Bond Strength in Resin Cementation Protocols for Fiber Posts in Endodontically Treated Teeth: An In Vitro Study.

The aim of this study is to analyze the effects of different endodontic irrigants and adhesive systems on the resin bond strength of fiber post cementation. In total, 144 single-rooted, unrestored human teeth were endodontically treated and randomly divided into 12 groups according to four endodontic irrigants (distilled water as control; EDTA 17%; NaOCl 5%; chlorhexidine digluconate 2%) and three different adhesive/resin cement systems (etch-and-rinse: orthophosphoric acid, Parabond® A+B/Paracore®; self-etch: ParaBond® Non-Rinse Conditioner, Parabond® A+B/Paracore®; Universal: ClearfilTM Universal Bond/ClearfilTM DC Core Plus). Forty-eight hours after post cementation, ten teeth from each group were cross-sectioned into three discs (cervical, middle and apical regions). Thirty specimens of each group (n = 30) were submitted to a push-out test at a crosshead speed of 1 mm/min. The remaining two teeth of each group were sectioned in the same manner, and the resin-dentin interface was evaluated using scanning electron microscopy (SEM). The results were statistically analyzed with the ANOVA test and Tukey's test (p < 0,01). The adhesive protocols and post space region showed no significant effect on bond strength (p > 0.01). The combination of NaOCl 5% and ClearfilTM Universal Bond reduced the adhesive strength (p < 0.01). The NaOCl 5%, in relation to other irrigants, significantly decreased the push-out bond strength.

Influence of different immediate dentin sealing strategies on bond strength of indirect resin nanoceramic restorations.

In this study, we evaluated the effect of four different strategies for bonding a CAD/CAM resin nanoceramic restoration (Lava Ultimate, 3M) to the dentin surface using a universal adhesive (Scotch Bond Universal, 3M) and adhesive resin cement (RelyX Ultimate, 3M) on the shear bond strength (SBS) and failure mode. The strategies comprised: (i) immediate sealing, immediate bonding; (ii) immediate sealing, bonding after 2weeks with provisional restoration; (iii) immediate sealing with flowable resin composite reinforcement and bonding after 2weeks with provisional restoration; and (iv) no immediate sealing, and bonding after 2weeks with provisional restoration. After bonding, all the specimens were thermocycled, shear tests were performed using a universal testing machine, and failure modes were determined using stereomicroscope and scanning electron microscopy. The highest mean SBS was recorded with immediate sealing, immediate bonding strategy. Most adhesive failures with exposed dentinal tubules were noted in specimens exposed to bonding after 2weeks with no immediate sealing, which was associated with the lowest SBS. Mixed failures predominated in all immediate dentin sealing groups. Immediate sealing with universal adhesives improves SBS, particularly in the single-visit approach, which has shown significantly better performance, whereas the provisional phase has a negative effect.

Effect of Immediate Dentin Sealing on the Bonding Performance of Indirect Restorations: A Systematic Review.

The popular immediate dentin sealing (IDS) technique is used to improve the bond strength of indirect restorations. This systematic review assessed whether bond strength is affected by the type of aging conditions, bonding agents, flowable resin composites, impression materials, temporary materials, and/or resin cement used within the IDS procedure. A comprehensive database search of PubMed, Embase, Scopus, Ovid Medline, Web of Sciences, Cochrane Library, Dentistry & Oral Sciences Source, and ProQuest was carried out up to 30 January 2024 without publication year or language limitations. Only in vitro full-texts regarding the effect of IDS on bond strength were included, and the quality of their methods was assessed via a Risk of Bias (RoB) test. In total, 1023 pertinent studies were initially found, and 60 articles were selected for review after screening for the title, abstract, and full texts. IDS application improves the bond strength of indirect restorations to dentin and reduces the negative effects of temporary materials on the bond durability of final indirect restorations. Filled dentin bonding agents or combinations with flowable resin composite are preferred to protect the IDS layer from conditioning procedures.

Color Matching between Resin Cements and Try-in Pastes in Glass Ceramics at Different Thicknesses

Aim: This study aims to assess how well light-cured resin cements and the corresponding try-in pastes match in terms of color. Materials and Methods: A1 color blocks containing three different types of ceramic materials were used to generate 120 specimens (5 × 5 mm2). These specimens were split into two thickness-based groups, and the groups were then randomly allocated to receive various kinds of resin cement. Composite substrate blocks with A3 color and dimensions of 4 mm thickness were used to simulate dentin substrates. Color measurements were taken before and after the application of try-in pastes and resin cements using a spectrophotometer. The obtained results were analyzed using the CIELab and CIEDE2000 frameworks, and statistical analysis was performed using a three-way ANOVA test and paired sample t-test with a significance level of α = 0.05. Results: There were no significant interactions between material, thickness, and cement in relation to color in both evaluation systems ( p &gt; .05). However, there were significant differences in the a* values (green-red axis) between the try-in pastes and resin cements ( p &lt; .05), while no significant differences were observed in the L* (lightness) and b* (blue-yellow axis) values ( p &gt; .05). Conclusion: The try-in pastes utilized for pre-cementation evaluation exhibited favorable color compatibility with the corresponding resin cements.

Bonding Pretreatment of Aesthetic Dental CAD-CAM Materials through Surface Etching with a Mixed Aqueous Solution of Ammonium Fluoride and Ammonium Hydrogen Sulfate.

Hydrofluoric acid (HF) is commonly used as an etchant for the pretreatment of dental computer-aided design/computer-aided manufacturing (CAD-CAM) materials, such as glass-ceramics and resin composites. Despite its effectiveness, the harmful and hazardous nature of HF has raised significant safety concerns. In contrast, ammonium fluoride (AF) is known for its relatively low toxicity but has limited etching capability. This study explored the potential of ammonium hydrogen sulfate (AHS), a low-toxicity and weak acid, to enhance the etching ability of aqueous AF solutions for the bonding pretreatment of CAD-CAM materials. This study investigated five types of aesthetic CAD-CAM materials: lithium disilicate glass, feldspathic porcelain, polymer-infiltrated ceramic networks, resin composites, and zirconia. Seven experimental etchants were prepared by varying the amount of AHS added to aqueous AF solutions, with each etchant used to etch the surfaces of the respective CAD-CAM materials. The treated surfaces were analyzed using scanning electron microscopy and confocal laser scanning microscopy. Additionally, the shear bond strength (SBS) of the CAD-CAM materials treated with a luting agent (resin cement) was evaluated. The results indicated that the AF1/AHS3 (weight ratio AF:AHS = 1:3) etchant had the most substantial etching effect on the surfaces of silica-containing materials (lithium disilicate glass, feldspathic porcelain, polymer-infiltrated ceramic networks, and resin composites) but not on zirconia. The SBS of the materials treated with the AF1/AHS3 etchant was comparable to that of the commercial HF etchant. Hence, an AF/AHS mixed solution could effectively etch silica-containing CAD-CAM materials, thereby enhancing their bonding capabilities.

Bioceramic and Resin-Based Sealers Removal Using XP-Endo Finisher: A Scanning Electron Microscopy Study

Abstract Objectives The aim of this study was to evaluate remaining filling materials of a bioceramic sealer (TotalFill BC sealer) and an epoxy resin sealer (AH Plus) after retreatment using a supplementary instrumentation (XP-endo Finisher). Materials and Methods Forty single-rooted teeth were selected for the study. The teeth were instrumented using ProTaper system and randomly divided into two groups (n = 20). Then they were obturated with either TotalFill BC/gutta-percha or AH Plus/gutta-percha using lateral compaction technique. Canals were retreated using ProTaper retreatment files and a solvent. The groups were subdivided (n = 10) according to the application or not of the XP-endo Finisher as a final step of retreatment. All roots were cleaved longitudinally and examined under scanning electron microscope to evaluate root canal filling remnants. A scoring system was utilized to quantify the amount of residual filling material at the three predetermined portions of each root canal.Statistical analysis was performed using IBM SPSS.25 with a significant value p &lt; 0.05. Data were compared using the Mann–Whitney test and Kruskal–Wallis test. Results There was no statistically significant difference in the remaining filling materials for each third of the root canal after initial retreatment procedure between the TotalFill group and AH Plus group. Similar results were observed among the TotalFill groups with or without the application of XP-endo Finisher supplementary step. However, the remaining filling materials of AH Plus in the middle third of root canal were significantly less after the XP-endo Finisher application (p = 0.015). Conclusion No retreatment protocol tested in this study allowed the total elimination of root canal filling materials. The residual root canal filling materials is similar for the bioceramic and resinous sealers. The XP-endo Finisher is not effective in improving the removal of bioceramic root canal filling material while it is able to improve the removal of resinous cement.

Assessing push-out bond strength in re-irradiated teeth: Universal resin cement performance in self-etch and self-adhesive modes.

To investigate the effect of cumulative doses of radiation on the pushout bond strength (BS) of a universal resin cement used in the self-etch (SE) and self-adhesive (SA) modes to the intraradicular dentin. Forty-eight human teeth were distributed into three groups (n = 16) according to the radiation therapy dose (RT): NoRT (no-radiotherapy), 70RT (70 Gy), and 70 + 70RT (70 Gy + 70 Gy). The teeth were redistributed into two subgroups (n = 8), according to the adhesive mode: SE (NoRT-SE, 70RT-SE, and 70 + 70RT-SE) and SA (NoRT-SA, 70RT-SA, and 70 + 70RT-SA). Data were statistically compared after BS test (ANOVA, Tukey's post hoc test, and Fisher's exact test). In the SA mode, BS was significantly higher in nonirradiated teeth compared with 70RT and 70 + 70RT (p < 0.0001). There were no significant differences between SE and SA modes in nonirradiated teeth (p = 0.14). In the 70RT group, SE mode increased BS compared with SA mode (p < 0.0001). Most specimens had adhesive and mixed failures in SA and SE modes, respectively. The universal resin cement in the SE mode had greater BS to the irradiated dentin. When teeth were re-irradiated, the universal resin cement had similar performance in terms of BS, regardless of the adhesive approach. There is no research establishing a correlation between radiotherapy and its impact on the BS of a universal resin cement used in SE and SA modes to intraradicular dentin.

Evaluation of mechanical properties of anatomically customized fiber posts using E-glass short fiber-reinforced composite to restore weakened endodontically treated premolars

ObjectiveThis study was conducted to assess the influence of combining different forms of fiber-reinforced composites (FRC) on the mechanical behavior and bond strength of compromised endodontically treated teeth (ETT).Materials and methodsEighty extracted human premolar teeth were randomly divided into five experimental groups according to the type of intra-radicular restoration and the canal preparation design which was either non-flared (Group 1), flared (Groups 2–5), closed-apex (Groups 1,3,5) or open-apex (Groups 2,4). Standard prefabricated fiber posts were used as intra-radicular restoration for Groups 1–3 while Groups 4–5 were restored with anatomically customized relined fiber posts. After composite core fabrication, all samples were sent for an artificial aging process. Fracture resistance and push-out bond strength tests were then carried out through a universal testing machine followed by mode of failure analysis via a stereomicroscope and scanning electron microscope.ResultsPairwise Log-Rank comparisons revealed that the survival rate of Group 2 and Group 3 was significantly lower than all other groups after artificial aging. The highest fracture resistance value (1796 N) was recorded in Group 5 and was significantly higher than that of the other groups (p < 0.05), while Group 2 exhibited the lowest fracture resistance (758 N), which was significantly lower compared to the other groups. Group 5 and Group 4 demonstrated a significantly higher push-out bond strength, at all root thirds, than Group 3, Group 2, and Group 1 (p < 0.05). The most frequently observed failure mode in the tested groups occurred between the resin cement and radicular dentin.ConclusionThe use of short fiber-reinforced composite (SFRC) to reline the prefabricated FRC post has been proven to have superior fracture resistance with favorable failure patterns and increased push-out bond strength values compared to standard prefabricated FRC posts.

Influence of 3D printed surface micro-structures on molding performance and dental bonding properties of zirconia

ObjectivesTo investigate the influence of the 3D printed micro-structured surfaces on the bond strength of zirconia to resin cement. MethodsZirconia specimens were divided into five groups based on manufacturing technique and surface preparation: (1) milled zirconia (M group); (2) milled zirconia airborne abraded (MA group); (3) printed zirconia (M group); (4) printed zirconia airborne abraded (PA group); and (5) printed zirconia with micro-structured surface (PM group). The surface morphology, cross-sectional morphology, and elemental composition were observed using a scanning electron microscope (SEM). Surface roughness was measured using a laser scanning confocal microscope (SLCM). Shear bond strength (SBS) was measured using a universal testing machine after bonding resin cement (n = 10). The failure modes of the bonded fracture interfaces were observed and counted using a stereomicroscope and a SEM. In addition, boundary dimensional accuracy (n = 10) and micro-structural dimensional accuracy (n = 20) of printed zirconia specimens with micro-structured surfaces were measured using digital calipers and Fiji software. The crystalline phase changes before and after surface treatment were investigated using X-ray diffractometry. Data was analysed using one-way ANOVA and Tukey HSD post-hoc tests (α = 0.05). ResultThe surface micro-structures of the PM group had regular morphology and no obvious defects. The surface roughness results showed that the PM group had higher Sa (42.21±1.38 um) and Ra (21.25±1.80 um) values than the other four groups (p < 0.001). The SBS test showed that the bond strength of the PM group reached 11.23 ± 0.66 MPa, which was 55.97% (p < 0.001) higher than that of the P group (7.20 ± 1.14 MPa). The boundary dimensional accuracy of the PM group was proficient (diameter: 99.63 ± 0.31%, thickness: 98.05 ± 1.12%), and the actual fabrication dimensions of the hexagonal micro-structures reached 77.45%-80.01% of the original design. The micro-structured surface did not affect the crystalline phase of zirconia. ConclusionsThe current study illustrates that 3D-printed microstructured surfaces effectively improve the bond strength of zirconia to resin cements. Clinical significanceWith the advantage of 3D printing, this study provides a new idea for improving the bonding properties of zirconia.

Evaluation of Retentive Strength of 50 Endodontically-Treated Single-Rooted Mandibular Second Premolars Restored with Cast Post Cores Using 5 Common Luting (Cement) Agents.

BACKGROUND A luting agent is a dental cement used to secure a dental restoration. This study aimed to evaluate retentive strength of 50 endodontically-treated single-rooted mandibular second premolars (extracted) restored using 5 common luting (cement) agents. MATERIAL AND METHODS Fifty single-rooted mandibular second premolars with adequate root length and uniform size/shape were decoronated. After completing endodontic biomechanical preparation and obturation, root canals of all specimens were prepared to receive a cast post core. Depending upon cementation type, CPC specimens were divided in 5 groups (10 each) (Gp): Zinc phosphate (Gp ZP), polycarboxylate (Gp PC), glass ionomer (Gp GI), resin-modified glass ionomer (Gp RGI), and resin cement (Gp RC). Retentive strength was determined using the adhesive failure pull-out test. Mean/standard deviations were calculated for tensile forces (in kilograms) and differences were determined using analysis of variance (ANOVA). Multiple comparison was performed using the t test. A P value of ≤0.05 indicated a statistically significant difference. RESULTS The order of mean tensile strength from higher to lower was Gp RC (21.46) >Gp RGI (18.17) >Gp GI (16.07) >Gp ZP (15.33) >Gp PC (13.63). Differences in retentive strengths between the cements were significant (P≤0.05). Multiple-group comparisons showed that except for Gp ZP and Gp GI, all groups differed significantly from each other. CONCLUSIONS All investigated cements provided optimal retentive strengths, with wide differences between them. Resin cements should be used when CPC removal is not anticipated, while polycarboxylate or zinc phosphate should be used if CPC removal is anticipated.

Evaluation of the microshear bond strength of resin cement to zirconia treated by different nanomaterials using the dip coating technique

Evaluation of the microshear bond strength of resin cement to zirconia treated by different nanomaterials using the dip coating technique