Fuji Plus Research Articles

A Comparative Evaluation of the Bonding Strength, Marginal Adaptation, and Microleakage of Dental Cements in Prosthodontics: An In Vitro Comparative Study.

The primary function of dental cement is to seal and support prosthodontic restorative materials. Proper selection of the dental cement contributes to the clinical success of the restoration. A total of 166 molar tooth samples were prepared to simulate the type of toothcommonly found in prosthodontic practice. Each sample was restored using one of the tested dental cement materials employing a prestabilized methodology. The performance of resin-modified glass ionomer cement (RMGIC) (GC Fuji PLUS Capsule, GC America, Alsip, IL), zinc phosphate cement (ZPC) (Dentsply Sirona, Charlotte, NC), and resin cement (RC) (RelyX ARC, 3M ESPE, Saint Paul, MN) in bonding strength, marginal adaptation, and microleakage was evaluated and compared. The bonding strength, marginal adaptation, and microgroove were tested using specific established methodologies. The outcomes were then analyzed using statistical analyses for means and standard deviations to compare different types of dental cement. The total outcome shows that the highest bonding strength with the highest mean was the resin cement, rating 24.8 MPa, followed by RMGIC and ZPC at 20.5and 18.9 MPa, respectively. The marginal adaptation scores indicate that RC had the highest score at a mean of 4, followed by ZPC at 3.2 and RMGIC at 2.5. The dye penetration measurements in millimeters revealed that ZPC had a penetration of 0.31 mm, RMGIC had a penetration of 0.25 mm, and RC had the least penetration at 0.20 mm. The results of the statistical data analysis show significant differences between the dental cements in bonding strength and marginal adaptation. In conclusion, resin cement demonstrated superior performance in bonding strength, marginal adaptation, and resistance to microleakage compared to RMGIC and zinc phosphate cement. These findings highlight the importance of selecting resin cement for achieving optimal clinical outcomes in prosthodontic restorations.

Micro-shear bond strength of a novel resin-modified glass ionomer luting cement (eRMGIC) functionalized with organophosphorus monomer to different dental substrates

ObjectivesThis study aims to assess and compare the micro-shear bond strength (μSBS) of a novel resin-modified glass-ionomer luting cement functionalized with a methacrylate co-monomer containing a phosphoric acid group, 30 wt% 2-(methacryloxy) ethyl phosphate (2-MEP), with different substrates (dentin, enamel, zirconia, and base metal alloy). This assessment is conducted in comparison with conventional resin-modified glass ionomer cement and self-adhesive resin cement. Materials and methodsIn this in vitro study, ninety-six specimens were prepared and categorized into four groups: enamel (A), dentin (B), zirconia (C), and base metal alloys (D). Enamel (E) and dentin (D) specimens were obtained from 30 human maxillary first premolars extracted during orthodontic treatment. For zirconia and metal alloys, 48 disks were manufactured using IPS e.max ZirCAD through dry milling and Co–Cr powder alloy by selective laser milling. Each group was further subdivided into three subgroups (n = 8) according to the luting cement used: (1) Fuji PLUS resin-modified glass ionomer luting cement (FP) as a control cement, (2) modified control cement (eRMGIC), and (3) RelyX U 200 (RU 200) self-adhesive resin cement. The two-way analysis of variance and Tukey's HSD were used to assess the data obtained from measuring the μSBS of the samples. ResultsThe results of this study showed that the mean μSBS values of eRMGIC were statistically higher compared to FP in all tested groups (p < 0.001). The mean μSBS results of eRMGIC were non-significantly different from those recorded by RU 200 for all substrates except for the dentin substrate, where the RU200 cement produced significantly higher strength (p < 0.001). The failure modes were limited to a combination of mixed and adhesive failures without pure cohesive failure. SignificanceThe functionalization of FP with an organophosphorus co-monomer (2-MEP) directly affects the adhesion performance of the functionalized cement, which may be utilized to develop a new type of acid-base cement. It exhibited a performance comparable to that of resin-based cement and should serve well under different clinical conditions.

Comparing Zirconium Crown Marginal Adaptation in Preparations with Two Different Occlusal Reductions.

This study aimed to assess and contrast the effects on the vertical marginal fit of full contour CAD/CAM-generated monolithic zirconia crowns at pre- and post-cementation levels with various occlusal reduction schemes (planar and flat) and cements. Forty sound human maxillary first premolars were sampled for this study. The samples were divided into two main groups with twenty samples in each group according to the occlusal reduction scheme as follows: Group A included a chamfer finishing line design with a planar occlusal reduction scheme and Group B included a chamfer finishing line design with a flat occlusal reduction scheme. Each group was sampled into two subgroups (n = 10) based on the type of cement as follows: resin-modified glass ionomer cement (Fuji Plus) for subgroups A1 and B1, and a universal adhesive system (Duo Estecem II) for subgroups A2 and B2. Marginal gaps were tested in four indentations using a Dino light stereomicroscope (230×). Paired T-tests and Student's t-tests were used to analyze the data. Before cementation, subgroup A1 scored the lowest mean of vertical marginal gap values, while subgroup B2 scored the highest mean; following cementation, subgroup A1 scored the lowest mean of vertical marginal gap values, and subgroup B2 scored the highest mean of vertical marginal gap values. A chamfer finishing line design with a planar occlusal reduction scheme could be a preferable occlusal reduction scheme.

Physicomechanical Characterization of a Novel Resin-Modified Glass Ionomer Luting Cement Functionalized with a Phosphate Functional Monomer

Background. Resin-modified glass ionomer cements (RMGICs) are characterized by their ability to chemically bond with the tooth structure and their fluoride release, making them commonly used to retain indirect restorations. However, inferior mechanical properties and solubility (SO) are their main drawbacks compared to the most recent resin-based cement. Aim of the Study. Formulate a novel brand of experimental RMGIC (eRMGIC), based on RMGIC by incorporating 2-(methacryloxy) ethyl phosphate (2-MEP), an organophosphorus monomer with the potential to enhance mechanical properties along with low SO. Materials and Methods. eRMGICs were prepared by the inclusion of 2-MEP monomer with different weight percentages (0–40 wt%) into the RMGIC’s liquid (Fuji PLUS, GC. Corp.), then their compressive strength (CS), flexural strength (FS), film thickness (FT), setting time (ST), SO, and water sorption were examined and compared to the conventional RMGIC. Furthermore, a scanning electron microscope analyzed their surface homogeneity and integrity. Shapiro–Wilk test of normality was used to analyze data, one-way analysis of variance, Dunnett T3, and Tukey’s honest significant difference post-hoc tests. Results. After 28 days and 180 days of storage, the values of CS of the eRMGICs were significantly higher. However, after 24 hr of storage, the values were comparable to the control group. The FS results showed a double-fold increase in different concentrations of eRMGICs through all the time intervals ( p &lt; 0.001 ) compared to conventional RMGIC. Furthermore, the inclusion of 2-MEP increased water uptake and decreased SO. The FT of experimental eRMGICs cement showed a statistically significant increase with increasing 2-MEP concentration. However, it was within the specification given by ISO 9917-1:2007. There was a decrease in the ST of eRMGICs compared to control cement; however, it was within the specification given by ISO 9917-2:2017. Conclusions. 2-MEP monomer showed encouraging results and could be used in producing new (eRMGICs) with enhanced physicomechanical properties, which can increase the longevity of cement and improve its ability to resist occlusal stresses without fracture.

Comparative evaluation of the main properties of dental cements for permanent fixation of non-removable denture structures

The study was conducted to compare the main characteristics of dental cements for permanent fixation of fixed dentures. Some materials, formed by the reaction of weak polymeric acids with inorganic glass powder. Dental cements have a number of advantages: due to adhesion, the material "join" the surface of the abutment tooth and the inner surface of the artificial structure; some permanent cements slowly release fluoride ions over time to maintain dental health; they do not dissolve in the oral fluid. Despite the advantages, these materials need further improvement in their mechanical performance. Laboratory tests were carried out in the conditions of the accredited in the system of UKR-SEPRO and licensed research laboratory of JSC "Stoma". The following basic properties were studied: mixing time (Tm, s), curing time (Tc, s), film thickness (μm), compressive strength (MPa), acid solubility (mm/h), adhesion to metal/dentin (MPa). The process of mixing the components of the "Compomer" material is 2.5 s longer than that of "Ketac Cem" and 7.7 s longer than that of "Fuji Plus". In the case of the "curing time" indicator, the "Fuji Plus" material is significantly different, with a curing time that is 4.5 s faster than that of "Ketac Cem" and half the "curing time" compared to "Compomer". "Ketac Cem" has the lowest "film thickness" value – (21.8±0.8) μm, which significantly differs (p≤0.05) from the materials selected for the study. The study of the compression resistance of the cements revealed their full compliance with the standard value according to ISO-9917-1:2007. The acid solubility of the tested cements is at the level of (0.14÷0.29) mm/h. The adhesion index of the tested cements fully meets the requirements of international standards. Keywords: permanent cement, non-removable denture structures, properties, adhesion, international standards.

COMPARATIVE EVALUATION OF FLUORIDE RECHARGE OF FLUORIDE RELEASING DENTAL MATERIALS BY FLUORIDATED DENTIFRICE : AN IN VITRO STUDY

Introduction: Fluoride releasing dental materials releases maximum fluoride within twenty four hours which reduces thereafter.If we could recharge fluoride on the daily basis,the caries preventive effect from fluoride releasing dental materials can be prolonged. Aim and Objectives: The present study is undertaken to compare and evaluate fluoride recharge of fluoride releasing dental materials by fluoridated dentifrice. Materials and Method: Materials used in this study are GC Fuji Type IX,Fuji Plus,Zirconomer Improved,Beautifil II LS. All restorative materials were mixed according to manufacturers instruction and standardized test pellets were made using autoclaved instruments in sterile plastic moulds. These test pellets were divided in various groups and brushed with fluoridated dentifrice accordingly . Results were evaluated statistically using Post Hoc test and ANOVA and correlation coefficient for which regression lines were drawn. Result: The mean fluoride release and recharge was maximum in Zirconomer Improved, followed by GC Fuji Plus ,then by GC Fuji Type IX and least by Beautifil II LS. Conclusion:Daily recharge of fluoride releasing dental materials with fluoridated dentifrices is recommended to increase the cariostatic effect.

Influence of Conventional Polymer, Hybrid Polymer and Zinc Phosphate Luting Agents on the Bond Strength of Customized Zirconia Post in Premolars-An In-Vitro Evaluation.

The aim was to identify the influence of conventional polymeric resin based cement (RC), hybrid polymer modified glass ionomer (RMGIC) and Zinc phosphate cement (ZPC) on the pull out strength of the customized zirconia post in premolars. Access cavity and root canals were performed in sixty premolar teeth with the standardized crown down technique (ProTaper Universal, Dentsply). Post space impressions were scanned, and the pre-sintered Zenostar Zr Translucent blanks (Weiland Dental, Pforzheim) were milled with the Opera-system to form the post. All prepared specimens were divided equally in three groups based on the cement type employed for luting as follows: group A: ZPC; group B (GC Fuji PLUS Capsule): RMGIC; group C (and RC (3M RelyX ARC). Ten specimens in each group were thermocycled (TC) at 5 and 55 °C in distilled water baths (40,000 cycles). Pull out bond strength was assessed using a universal testing machine at 0.5 mm/min. The means and standard deviations were compared using ANOVA and Tukey Kramer multiple comparisons tests. A significant difference among the cement groups as well as between TC and non-thermocycled (NTC) groups (p < 0.05) was observed. The highest tensile stress was demonstrated among group C (Resin, 69.89 ± 4.81 (NTC), 64.06 ± 4.36 (TC)) with the least in group A, (zinc phosphate, 43.66 ± 5.02 (NTC), 37.70 ± 5.10 (TC)) for both groups. Group A presented with 100% adhesive bond failures, followed by 80% in group C and 70% in group B, respectively. A similar outcome was observed in the TC group for the cement; however, unlike the NTC group, the TC group showed more cohesive failures compared to the NTC mixed failure. Dual cure polymer based cement demonstrated higher bond strength and efficient adhesive bonding of the customized Zr post with root dentine compared to zinc phosphate (non-polymeric) and RMGIC (hybrid polymer). Thermocycling compromised Zr post adhesive bonding to root dentin.

Bonding properties of third-generation zirconia CAD-CAM blocks for monolithic restorations to composite and resin-modified glass-ionomer cements.

To compare the interfacial fracture toughness (IFT) of two MDP-based composite cements and a resin-modified glass-ionomer cement (RMGIC) with third-generation zirconia CAD-CAM restorations using two different airborne-particle abrasion (AB) pressures. Blocks were cut into prisms (n=60), split and sintered to the desired equilateral half prisms. Half-prisms were divided into two groups for AB at 0.5 or 2.5 bar with 50 µm Al2O3 particles. Each group was then further divided into 3 subgroups, and half-prisms were bonded to their counterparts with Panavia V5 (V5), Panavia Self Adhesive Cement Plus (SA), or RMGIC Fuji Plus (n=10/group). The IFT was determined using the Notchless Triangular Prism test in a water bath at 36°C after thermocycling (10,000 cycles). Surface roughness and SEM analyses were performed for representative zirconia samples after AB, and composite cements were tested for flexural strength and wettability. SA (2.5 bar) showed a significantly higher IFT. The 3 other groups with SA and V5 showed no significant difference in their IFT values regardless of the AB pressure (1-way ANOVA). Weibull analysis of SA was higher than V5. All RMGIC samples debonded while thermocycling, and were, therefore, not included in the statistical analysis. Surface roughness increased with increasing AB pressure, and both cements showed similar flexural strength values and good wettability. Contrary to RMGIC, composite cements show high performance with zirconia after AB. Increasing AB pressure enhances the micromechanical retention of composite cement. Future perspectives should include study of the effect of AB pressure on zirconia surface properties.

Evaluation of the Water Sorption and Solubility Behavior of Different Polymeric Luting Materials.

Objective: The study evaluated the water sorption (WSP) and water solubility (WSL) characteristics of different luting agents over a 180-day water storage period. Materials and Methods: Nine luting materials, i.e., conventional resin cement: Panavia F (PF), Rely X ARC (RA), self-adhesive resin cement: Rely X Unicem (RU), Breez (BZ), Maxcem Elite (MX), BisCem (BC) and resin-modified glass ionomer cement: FujiCem (FC), FujiPlus (FP) Rely X luting plus (RL) were assessed and fifty-two-disc specimens of each material were fabricated. All specimens were desiccated until a constant weight (W0) was reached. Thirteen specimens for each luting material were then randomly assigned to one of the four water immersion periods (7, 30, 90, and 180 days). After each period, the specimens were removed from the water and weighed to get W1. The samples were again desiccated for a second time and W2 was measured. Both WSP and WSL were determined by the following equations: WSP (%) = (W1 − W2) × 100/W0 and WSL (%) = (W0 − W2) × 100/W0. Assessments were performed following ISO standards. ANOVA was used to assess the effect of luting agent and time period on water sorption and solubility. Pair-wise comparisons were adjusted using Tukey’s multiple comparison procedure. A significance level of 0.05 was used for all statistical tests. Results: The highest mean WSP and WSL (WSP/WSL) were demonstrated by resin-modified glass-ionomers (RL 18.32/3.25, FC 17.08/4.83, and FP 14.14/1.99), while resin luting agents showed lower WSP and WSL results (PF 1.6/0.67 and RA 1.76/0.46), respectively. The self-adhesive agents exhibited a wide range of WSP and WSL values (RU 1.86/0.13, BZ 4.66/0.93, and MX 3.68/1.11). Self-adhesive cement showed lower WSP and WSL compared with the resin-modified glass-ionomers (p < 0.05). All the materials reached equilibrium after 90-days. Conclusions: Resin-based luting materials have the lowest sorption and solubility. Rely X Unicem self-adhesive luting materials were comparable to resin luting materials for WSL and WSP. Resin-modified glass-ionomer showed the highest water sorption and solubility compared with both resin and self-adhesive materials.

Adhesion between Biocomposites and Different Metallic Structures Additive Manufactured

This study was concerned with the adhesion of resin cement to metal surfaces obtained by selective laser melting process (SLM), and how it could be improved the bond strength at the biocomposite-metal junction. The SLM substrates were manufactured out of pure titanium (Ti), Ti6Al7Nb, and CoCr alloys. The metallic surfaces were covered with 5 types of biocomposites: 2 commercially resin-modified glass-ionomer cements (GC Fuji Plus and KETAC CEM) and 3 types of in-house developed materials. These biocomposites were mechanical characterized under compression and bending trials. The biocomposites-metal adhesion was settled both on as built metallic surfaces and after they were sandblasted with alumina. All the sandblasted SLM surfaces presented higher adhesion strength in comparison with the untreated specimens. The CoCr specimens show the highest bonding value. Additionally, the morphological aspects of joining interfaces were investigated using a scanning electron microscope (SEM). The mechanical properties and metal adhesion of these biocomposites were influenced by the liquid powder ratio. It is essential to apply a surface treatment on SLM substrate to achieve a stronger bond. Also, the chemical composition of biocomposite is a major factor which may improve the adhesion of it on different metallic substrates.

Effect of Thermocycling on the Compressive Strength of Selected Luting Cements

Introduction: The purpose of this in vitro study was to evaluate the effect of thermocycling on the compressive strength of selected luting cements. Material and methods: 5 types of luting cements were tested. A total of thirty cylindrical specimens measuring 6mm in height and 4mm in diameter were prepared for each type of cement which were then divided into two groups ie Group 1: Exposure, and Group 2: Control. Both groups were stored in distilled water at 37°C for 24 hours. Group 1 was subjected to 500 cycles in a thermocycling baths of 5ºC and 55ºC with 20 seconds in each bath. Group 2 was not exposed to thermocycling procedure. The compressive strength for each cement type was determined by using a universal testing machine. Results: Resin adhesive cement had the highest compressive strength; followed by conventional glass ionomer cement (GIC) whilst resin modified GIC was the least. Thermocycling had no significant effect on the compressive strength of RelyXTM ARC and Fuji I (p&gt;0.05), but a significant effect on Fuji I CAPSULE, Fuji CEM, Fuji Plus CAPSLUE (p&lt;0.05) was observed. Conclusion: The effect of thermocycling on the compressive strength of luting cements differed considerably with respect to their chemical compositions.

Microleakage patterns of glass ionomer cement at cement-band and cement-enamel interfaces in primary teeth

In-vitro studies of microleakage are an initial screening method to assess the maximum theoretical loss of sealing ability in-vivo. Our objective was to determine and compare microleakage patterns of conventional glass ionomer cement (GIC) and resin-modified GIC (RMGIC) for band cementation. Forty caries-free second primary molars were randomly divided into two groups of 20 teeth each. Preformed molar bands in the two groups were cemented to enamel with one of two types of cement: Conventional GIC (Fuji I, GC Corporation; Tokyo, Japan) and RMGIC (Fuji Plus, GC Corporation; Tokyo, Japan). A dye penetration method was used for microleakage evaluation. Microleakage was determined by a stereomicroscope for the cement-band and cement-enamel interfaces. Statistical analysis was performed with Kruskal-Wallis and Mann-Whitney U tests. The mean microleakage value for conventional GIC (Fuji I) at cement-band and cement-enamel interfaces was 2.41 mm and 2.15 mm, respectively. The mean microleakage value for RMGIC (Fuji Plus) at cement-band and cement-enamel interfaces was 0.44 mm and 0.46 mm, respectively. Compared to conventional GIC, RMGIC showed less microleakage at both cement-band and cement-enamel interfaces. P < 0.001 and it was statistically highly significant. Bands cemented with RMGIC had significantly less microleakage between the cement-band and cement-enamel interfaces than conventional GIC.

A COMPARATIVE IN-VITRO STUDY ON WEIGHT CHANGE OF CONVENTIONAL GLASS IONOMER, RESIN MODIFIED GLASS IONOMER CEMENT AND COMPOSITE RESIN

Objective: To compare the weight change of two commercially available variants of each; conventional GIC, RMGIC &amp; resin composite when stored at 100% humidity at mouth temperature (37˚C).&#x0D; Materials and Methods:The samples of Fiji IX, Chemfil Rock, and Fuji plus were allowed to set for 15 minutes. Light cured Fuji II LC were polymerised for 20 seconds, kept in an incubator for 60 minutes and for storage in deionized H2O at temperature of 37°C as per instructions of the company. Weight changes were for all the sample were carried out using an analytical balance at two intervals; Pre and post immersion of samples in the said medium. The weight changes were recorded at 24 hours, 4 days, 1 week, 2 weeks, 3 weeks, and 4 weeks. Surface water was blotted post immersion for every sample and weighed. For all samples the average and standard deviation evaluated &amp; t test stats to see any important differences.&#x0D; Results:At 24 hours, on an average the maximum wt% change was noted for self-cure Fuji Plus (3.350 ± 0.0034%) this weight change was significantly higher when p value was considered significant at 0.05. At 4 weeks the average wt% change remained highest for self-cured rein modified glass ionomer (4.250 ± 0.0049%).&#x0D; Conclusion:RMGIC had maximum variation in weight when stored at 37˚C in deionized water as compared to conventional GIC and dental composite materials.

Microleakage of class II restoration with zirconia inlay: An in vitro study

Background: Class II restoration with zirconia inlay is concerned by numerous studies about the luting coupling between zirconia inlay and teeth. The present study was performed to evaluate the microleakage of Class II zirconia inlayusing two different luting agents and compare to direct restoration using bulk fill composite. Aims: To evaluate the microleakage of Class II restorations using three different techniques. Materials and methods: The study was performed in laboratory with three groups. Each of thirty extracted human teeth was prepared a class II cavity with the same dimensions, then these teeth were randomly divided into 3 groups restored by 3 different approaches. Group 1: zirconia inlay cemented with self-etch resin cement (Multilink N); Group 2: zirconia inlay cemented with resin-modified glass ionomer cement (Fuji Plus); Group 3: direct composite restoration using bulk fill composite(Tetric N-Ceram Bulk Fill). All restorations were subjected to thermal cycling (100 cycles 50C – 55 0C), then immersed to 2% methylene blue solution for 24 hours. The microleakage determined by the extent of dye penetration along the gingival wall was assessed using two methods: quantitative and semi-quantitative method. Results: Among three types of restorations, group 1 demonstrated the significantly lower rate of leakage compared to the others, while group 2 and 3 showed no significant difference. Conclusion: Zirconia inlay restoration cemented with self-etch resin cement has least microleakage degree when compare to class II zirconia inlay restoration cemented with resin-modified glass ionomer cement and direct composite restoration using bulk fill composite. Key words: inlay, zirconia ceramic, class II restoration, microleakage.

Effects of Curing Modes on the Microhardness of Resin-modified Glass Ionomer Cements.

ObjectiveThis study evaluated the effects of curing modes on surface microhardness of visible light-cured resin-modified glass ionomer cements (VLC RMGIC) and a giomer after different storage periods in comparison to auto-cured resin-modified glass ionomer cements (AC RMGIC).Materials and MethodsThe following materials were used: VLC RMIC: Fuji II LC Improved, Photac Fil Quick Aplicap, AC RMGIC: Fuji Plus, Fuji VIII and Giomer: Beautifil II. The measurements of microhardness were performed using a Vickers test (100 g loads were applied for 10 s) in the following time intervals: immediately after the recommended cure and after 1, 7 and 14 days of immersion in distilled water. Five samples (d=4 mm, h=2 mm) were prepared for each combination of curing mode and tested material.ResultsAfter 14 days, an improvement of microhardness was evident in all tested materials. The full factorial ANOVA identified a highly significant (p<0.001) effect of the factors “material”, “time” and “curing mode (“low”, “soft“, „high”) for the light-cured materials Beautifil II, Fuji II LC and Photac Fil Quick. There was a statistically significant difference in the microhardness between different material types (Beautifil II˃Fuji II LC˃Photac Fil Quick˃Fuji Plus˃Fuji VIII) and curing modes (low ˂soft ˂high).ConclusionsMaterial type had the greatest impact on microhardness, followed by the factor of time, while curing modes showed a considerably smaller influence on microhardness of the light-cured materials.

Biocompatibility and Surface Characteristics of Resin-Modified Glass Ionomer Cements with Ammonium Quaternary Compounds or Silver Nanoparticles: AnIn VitroStudy

Glass ionomer cements are materials with diverse clinical applications. Its use is indicated in patients with special needs, pediatric patients, and the elderly; accordingly, it is important to know its properties. The aim of the present study was to determine the cytotoxicity, surface roughness, microhardness, and surface characteristics of GC Fuji ORTHO LC and GC Fuji PLUS resin-modified glass ionomer cements (RMGICs) with 1 and 2% of benzalkonium chloride, cetylpyridinium chloride, hexadecyltrimethylammonium bromide, or silver nanoparticles. All the experimental groups increase or decrease statistically significantly the VHN (P&lt;0.05) compared with the control group, except for GC Fuji PLUS added with hexadecyltrimethylammonium bromide 1 wt%. In the same way, all groups show a statistically significant (P&lt;0.05) increase or decrease in Ra compared with the control group except for GC Fuji ORTHO added with benzalkonium chloride 2 wt%, GC Fuji PLUS added with benzalkonium chloride 2 wt%, and GC Fuji PLUS added with cetylpyridinium chloride 2 wt%. The SEM micrographs show similar surface images between the control and experimental groups. When a dental material is modified, it is important to reevaluate its biological and mechanical characteristics. In the present study, all the additions modified the cytotoxicity and surface characteristics of RMGICs, by increasing or decreasing these properties.

Influence of Luting Materials on the Retention of Cemented Implant-Supported Crowns: An In Vitro Study.

The retention force of cemented crowns on implant abutments with various luting materials was evaluated. Cobalt–chromium crowns were cemented onto tapered titanium abutments (Camlog) with eugenol-free temporary cement (RelyX TempBond NE), composite-based temporary cement (Bifix Temp), zinc phosphate cement (Harvard Cement), glass-ionomer cements (Meron, Fuji I), and resin-modified glass-ionomer cements (Fuji II, Fuji Plus, Ketac Cem Plus). Specimen aging via hydrostress was performed in artificial saliva at 37 °C for 14 days (S1), followed by hydrothermal stress with thermocycling (S2). The crowns were removed, and the force was recorded (T1). Subsequently, the crowns were recemented, aged, and removed, and the force was recorded (T2, T3). The retention forces differences were statistically significant according to the storage conditions at T1 (p = 0.002) and T3 (p = 0.0002). After aging (S1), Ketac Cem Plus had the highest retention force median value difference (T3 versus T1) (−773 N), whereas RelyX TempBond NE had the lowest (−146 N). After aging (S2), Meron had the highest retention force median value difference (−783 N), whereas RelyX TempBond NE had the lowest (−168 N). Recementation decreased the retention force of the implant-supported cobalt–chromium crowns cemented and recemented with the same luting materials. Luting materials (at T1) and aging conditions significantly impacted the retention force.

EVALUATION OF SHEAR BOND STRENGTH OF HIGH-PERFORMANCE POLYMERS TO ITS RESIN VENEERING AND TO DENTIN (IN VITRO STUDY)

INTRODUCTION: : Looking through the wide range of prosthetic options High-performance polymers properties. Needs over layering resin veneer, bonded by a special adhesive, this adds an additional challenge to achieve adequate bond strength, also its bonding to tooth structure remains difficult. OBJECTIVES: To evaluate shear bond strength of CAD/CAM High-performance polymers (BioHPP) with its CAD/CAM veneering composite using two different adhesives, as well as to dentin using two types of cements. MATERIALS AND METHODS: This in vitro study, for Group I, twenty BioHPP discs with their CAD/CAM veneering composite, were milled and divided randomly into two subgroups (n =10) according to the adhesive system used. Subgroup IA: using DTK adhesive (dualhardening adhesive). Subgroup IB: using Combo.lign (dual-hardening adhesive). For Group II, twenty CAD/CAM High-performance polymers (BioHPP) discs were milled and divided into two subgroups according to the different cements used to lute to dentin surface. Subgroup IIA: using: RelyX Unicem resin cement, subgroup IIB: using Fuji Plus GI cement. After water storage, thermocycling (1200 cycles, 5°C/55°C) corresponding to one year of clinical service, all the specimens were subjected to shear force until failure and the results in the various groups were compared and statistically analyzed. Modes of failure were assessed. RESULTS: Mean SBS were as follows: subgroup IA (DTK adhesive 6.238), subgroup IB (combo.lign2.42), subgroup IIA (RelyX Unicem 2.07) and subgroup IIB (Fuji Plus 3.77). Mann-Whitney test demonstrated significant differences between the two subgroups in groups I and II (U= 2.0, P=.001) (U=17, P=.013) respectively. Stereomicroscope revealed that mixed and adhesive failure were the most dominant mode of failure. CONCLUSIONS MDP-Containing Self-adhesive Resin (DTK adhesive) is recommended as efficient adhesive to increase the shear bond strength of the veneering composite to BioHPP. Also Fuji Plus showed better bond strength than RelyX Unicem with BioHPP and dentin.

Effect of Resin-modified Glass Ionomer Cement Dispensing/Mixing Methods on Mechanical Properties.

Resin-modified glass ionomer cements (RMGIs) are often used for luting indirect restorations. Hand-mixing traditional cements demands significant time and may be technique sensitive. Efforts have been made by manufacturers to introduce the same cement using different dispensing/mixing methods. It is not known what effects these changes may have on the mechanical properties of the dental cement. The purpose of this study was to evaluate the mechanical properties (diametral tensile strength [DTS], compressive strength [CS], and fracture toughness [FT]) of RMGIs with different dispensing/mixing systems. The RMGI specimens (n=14)-RelyX Luting (hand mix), RelyX Luting Plus (clicker-hand mix), RelyX Luting Plus (automix) (3M ESPE), GC Fuji PLUS (capsule-automix), and GC FujiCEM 2 (automix) (GC)-were prepared for each mechanical test and examined after thermocycling (n=7/subgroup) for 20,000 cycles to the following: DTS, CS (ISO 9917-1) and FT (ISO standard 6872; Single-edge V-notched beam method). Specimens were mounted and loaded with a universal testing machine until failure occurred. Two-/one-way analysis of variance followed by Tukey honestly significantly different post hoc test was used to analyze data for statistical significance ( p<0.05). The interaction effect of both dispensing/mixing method and thermocycling was significant only for the CS test of the GC group ( p<0.05). The different dispensing/mixing methods had no effect on the DTS of the tested cements. The CS of GC Fuji PLUS was significantly higher than that of the automix version ( p<0.05). The FT decreased significantly when switching from RelyX (hand mix) to RelyX Luting Plus (clicker-hand mix) and to RelyX Luting Plus (automix) ( p<0.05). Except in the case of the DTS of the GC group and the CS of GC Fuji PLUS, thermocycling had a significant effect reducing the mechanical properties of the RMGI cements ( p<0.05). Introducing alternative dispensing/mixing methods for mixing RMGIs to reduce time and technique sensitivity may affect mechanical properties and is brand dependent.

Effect of Luting Cements On the Bond Strength to Turkom-Cera All-Ceramic Material.

BACKGROUND:The selection of the appropriate luting cement is a key factor for achieving a strong bond between prepared teeth and dental restorations.AIM:To evaluate the shear bond strength of Zinc phosphate cement Elite, glass ionomer cement Fuji I, resin-modified glass ionomer cement Fuji Plus and resin luting cement Panavia-F to Turkom-Cera all-ceramic material.MATERIALS AND METHODS:Turkom-Cera was used to form discs 10mm in diameter and 3 mm in thickness (n = 40). The ceramic discs were wet ground, air - particle abraded with 50 - μm aluminium oxide particles and randomly divided into four groups (n = 10). The luting cement was bonded to Turkom-Cera discs as per manufacturer instructions. The shear bond strengths were determined using the universal testing machine at a crosshead speed of 0.5 mm/min. The data were analysed using the tests One Way ANOVA, the nonparametric Kruskal - Wallis test and Mann - Whitney Post hoc test.RESULTS:The shear bond strength of the Elite, Fuji I, Fuji Plus and Panavia F groups were: 0.92 ± 0.42, 2.04 ± 0.78, 4.37 ± 1.18, and 16.42 ± 3.38 MPa, respectively. There was the statistically significant difference between the four luting cement tested (p < 0.05).CONCLUSION:the phosphate-containing resin cement Panavia-F exhibited shear bond strength value significantly higher than all materials tested.