Light Transmission of Various Aesthetic Posts at Different Depths and Its Effect on Push-Out Bond Strength, Microhardness of Luting Cement

Background and Objectives: One requirement for the cemented post is the light transmittance on its entire length up to the deepest portion of a root canal to ensure the complete polymerization of resin cement. This study aimed to determine the light transmission ability in different aesthetic posts at different depths and its effect on the push-out bond strength and microhardness of luting cement at the corresponding interface. Materials and Methods: Twenty endodontic posts from glass fiber posts (GFP), zirconia ceramic posts (ZCP), and highly translucent zirconium oxide posts (HTZP) were sequentially sectioned into 12.8 and 4 mm lengths after recording the light intensity using a dental radiometer. Sixty single rooted premolar teeth root canals were treated and implanted vertically in a resin block. The post space was prepared and cemented with GFP, ZCP, and HTZP posts with twenty samples each. The root portion of teeth samples were sectioned into cervical, middle, and apical portion. A universal testing machine was utilized for the push-out bond strength test for the first ten samples from each group. The remaining ten samples from each group were used for the microhardness test using a micro-indenter instrument. The data were statistically analyzed using one-way Analysis of variance and Tukey HSD tests at p < 0.05. Results: The GFP endodontic postpresented with significant highest light translucency compared to HTZP, which was significantly higher than ZCP. GFP posts showed significantly higher bond strength per unit area compared to ZCP at analogous cross sections. The hardness of luting cement was also significantly higher amongst all tested endodontic posts. Conclusions: GFP high light translucency enhanced the curing of the luting resin cement that resulted in harder cement and a stronger bond supported by hardness and push-out tests. These findings suggest that GFP is preferred to be used with light-cured luting cements for restoration of endodontically treated teeth.

The Use of Innovative Materials in the Organization of Clinical Treatment in Dentistry

The article examines the features of the use of innovative materials in the organization of clinical treatment in dentistry. In modern conditions, solving the problem of patient safety is one of the main conditions for the functioning of medicine in general and dentistry in particular. For this reason, the search for innovations in the field of antimicrobial protection and, together with it, the functionality of various materials is one of the main tasks of researchers in the field of dentistry. Nanomaterials, which are made on the basis of graphene, are able to demonstrate excellent antimicrobial properties. These materials have the ability to disrupt the integrity of the bacterial cell membrane and produce reactive oxygen species (ROS). These materials are widely used in the manufacture of dentures, they are incorporated in the composition of composite resins and luting cements in the organization of restorative treatment, are used for the manufacture of adhesive materials. Many experts recognize that these materials are the future of dental practice, since they have the ability to provide a high level of functionality and safety.

Comparison of Sorption and Solubility Behavior of Four Different Types of Glass Ionomer Luting Cements in Artificial Saliva

Background: Luting cement provides the connection between crowns and tooth structure. The sensitivity, solubility, and decomposition stages of the cement after the hardening stage are still subjects of relative controversy. These characteristics could lead to a poor connection between the braces and the teeth, increased probability of decay, and decalcification. The present study aimed to evaluate the adsorption and solubility of 4 types of glass ionomer cement. Methods: Four luting cements were examined. A total of 10 specimens were prepared for each material following the manufacturer’s instructions, and the sorption and solubility were measured in accordance with the ISO 4049’s. Specimens were immersed in artificial saliva for 30 days, and were evaluated for sorption and solubility by first weighting them before incubation (W1), then immersing them in artificial saliva, dehydrating them in an oven for 24 hours, and weighing them again (W2 and W3, respectively). The data were analyzed using SPSS software version 21. One-way analysis of variance (ANOVA) followed by Tukey post hoc test was used to examine the differences among groups (α = 0.05). Results: As for the both sorption and solubility, there was a significant interaction between the sorption and solubility of all materials (P<0.001). The sorption values in artificial saliva were highest for glass ionomer cement Riva Luting followed by GC Fuji 1 and Cavex, whereas the least value was observed for Meron (P<0.000). As for solubility, it was significantly higher in Cavex followed by GC Fuji1 and Meron, but it was significantly lower in Riva Luting. Conclusions: It was determined that the weight changes of glass ionomer cements significantly varied among all the materials. Riva Luting followed by GC Fuji 1 had the highest water sorption, and the solubility was significantly higher in Cavex followed by GC Fuji1. Meron improved both water sorption and solubility properties among all glass ionomer cements.

Retention Force of Glass Ionomer Based Luting Cements with Posterior Primary Zirconium Crowns – A Comparative in Vitro Study

Objective: To determine the retentive force of three glass-ionomer luting cements used with prefabricated primary zirconium crowns (PPZCs) and to assess whether the retentive force was dependent on cementation material or different PPZCs brands. Study design: Four mandibular right second molar PPZCs were selected, one each from four manufacturers–NuSmile®ZR, Sprig Crowns, Cheng Crowns and Kinder Krowns. Silicone impressions of the outer surface of crowns were taken; stone dies prepared and reduced to fit the corresponding brand. 24 alginate impressions of each die obtained and filled with core buildup flowable composite. 96 composite tooth-replicas thus achieved were divided into four groups and further categorized into three subgroups of eight samples based on luting cements used – BioCem, FujiCEM®2 and KetacCem. Samples were thermocycled, placed in artificial saliva for one week followed by assessment of retentive force for crown dislodgment and failure mode. Results: Data was statistically evaluated using two-way ANOVA, HSD (P &lt;0.05). KetacCem had the lowest retentive force while BioCem showed comparatively higher value to FujiCEM®2. Adhesive failure modes were predominant with cement mainly adhering to crown’s internal surface. Conclusions: Resin-based GI cements offered superior retention than conventional GI cements for PPZCs and retentive force was dependent on cement type.

In Vitro Evaluation of the Effect of Different Luting Cements and Tooth Preparation Angle on the Microleakage of Zirconia Crowns

Introduction. Discrepancy between the crown border and prepared tooth margin leads to a microleakage that eases the penetration of microorganisms and causes the dissolution of luting cement consequently. Several factors should be considered to achieve optimal fitness, including tooth preparation taper and type of cementing agent. The study aimed to determine the relation of tooth preparation taper and cement type on the microleakage of zirconia crowns. Materials and Methods. Fifty-six freshly extracted premolars without caries and restorations were selected as the study sample and divided into two groups of different tapering degrees (6 and 12 degrees). Zirconia copings were designed and fabricated by the CAD/CAM system. The samples were divided into four subgroups for cementation, and each subgroup was cemented with a different luting cement (n = 7). After 5000 thermocycles at 5°C–55°C and dye penetration, the specimens were sectioned in the mid-buccolingual direction, and a digital photograph of each section was taken under a stereomicroscope. Data were analyzed by the Kruskal–Wallis and Mann–Whitney tests (α = 0.05). Results. The results showed significant differences among the four types of luting cement in marginal permeability (PV < 0.001). Regardless of the type of cement, the 12-degree tapering resulted in a lower microleakage (46.4% without microleakage) with statistically significant differences from the 6-degree tapering (PV = 0.042). Conclusion. Within the limitations of this study, increasing the tapering degree of the prepared tooth for CAD/CAM zirconia copings improved the marginal fit and decreased the microleakage score. In addition, total-etch resin cement indicated the least microleakage.

Comparative Evaluation of Flexural Strength and Modulus of Elasticity of Three Adhesive Luting Cements at Different Time Intervals under Oral Simulated Conditions: An In Vitro Study

Aim The purpose of this study was to compare and evaluate the flexural strength and modulus of elasticity of three adhesive luting cements as a function of specimen age, effect of storage media, and effect of curing through porcelain. Materials and Method Twenty samples fabricated for self-cure resin-modified glass ionomer cement (GIC; RelyX Luting 2, 3M ESPE, United States) were classified as group 1, whereas 40 samples fabricated for two dual-cure resin cements (20 samples each), Universal Resin Cement (Ammdent, Italy) and Maxcem Elite (Kerr Australia Pty. Ltd.), were classified as groups 2 and 3, respectively. The dual-cure cements were photo-activated using light cure unit with an intensity of 550 mW/cm2 in nine overlapping sections for 20 seconds per section on both sides. A total of 60 samples (20 samples in each group) were fabricated and tested using universal testing machine to compare flexural strength and modulus of elasticity of resin-modified GIC with two dual-cure adhesive resin cements, to determine the influence of storage of the specimens in artificial saliva at 37°C for 24 hours and to determine the influence of curing through porcelain disk of 2 mm thickness on these properties. Results The overall mean flexural strength and modulus of elasticity of resin-modified GIC was less than the dual-cure resin cements. The values reduced for resin-modified GIC when the samples were tested after 24 hours of storage in saliva, whereas an increase in the strength was seen for dual-cure cements. The curing through porcelain disk reduced the properties of dual-cure cements. Maxcem Elite showed better overall mean flexural strength and modulus of elasticity in all the parameters. Conclusion When comparing all three cements, both dual-cure cements showed better flexural strength and modulus of elasticity compared to resin-modified GIC, which indicates their use in cementation of fixed restorations.