Riva Light Cure Research Articles

Evaluation of the cytotoxicity of contemporary glass-ionomer cements on mouse fibroblasts and human dental pulp cells.

This study aimed to evaluate the cytotoxic effects of different types of contemporary GICs on human dental pulp cell (hDPCs) and mouse fibroblast (L929) cultures. Three high-viscosity GICs (HVGIC; GC Equia Forte, Riva Self Cure, IonoStar Plus), three resin-modified GICs (RMGIC; Photac Fil, Riva Light Cure, Ionolux), and a metal-reinforced GIC (MRGIC; Riva Silver) were investigated. Twelve disc-shaped specimens of each material were prepared and stored in Dulbecco's modified Eagle medium (DMEM). L929 fibroblasts and DPCs were then cultured in 96-well plates. Uncultured DMEM was used as a negative control. Mitochondrial dehydrogenase activity (MTT) assays were performed to detect cell viability after 24, 48, and 72h. Data were analysed using Mann-Whitney U and Friedman tests followed by a Bonferroni-corrected Wilcoxon signed rank test, with the statistical significance set at P < 0.05. Toxicity levels varied between the cell-culture systems. MTT assays of L929 cells showed significant differences in percentages of viable cells, as follows: Riva Self Cure = Riva Silver > GC Equia Forte > IonoStar Plus = Riva Light Cure = Photac Fil > Ionolux. MTT assays of DPCs showed the percentages of viable cells to be significantly lower for the Ionolux group when compared to the other GICs, which did not differ significantly from one another. With the exception of Ionolux, none of the other GICs tested showed any toxicity, and in fact, they all induced cell proliferation (> 100% cell viability). Although the degree of toxicity varied between the two cell-culture systems investigated, all the GICs tested, with the exception of Ionolux, performed favorably with regard to cytotoxicity (> 100% cell viability in both cell systems).

Surface morphological and physical characterizations of glass ionomer cements after sterilization processes.

The aim of this study was to investigate if sterilization methods would promote changes in the selected adhesion-related surface properties of glass ionomer cements (GICs). Riva self-cure (RSC) and Riva light-cure (RLC) GICs were tested. Thirty samples were prepared according to the type of material (RSC and RLC) and sterilization method: hydrogen peroxide gas plasma (HPGP), steam sterilization (SS), and no sterilization (n = 5 per group). A Teflon matrix (5 × 2 mm) was filled with one of the GICs to produce the samples. For the groups with the RLC material, the samples were light cured using a light curing unit for 20 s. After 24 hr, finishing and polishing were performed in all samples and then they were sterilized. Surface roughness, wettability, and micromorphology were accessed using a profilometer, a goniometer, and a scanning electron microscopy, respectively. Data were statistically analyzed through a two-way ANOVA and Tukey post-hoc test (p < .05). Both sterilization methods promoted similar roughness values to the nonsterilized samples (p > .05). HPGP decreased contact angle for RSC (p < .01), and SS increased contact angle for RLC (p < .01). Samples subjected to HPGP presented similar surface micromorphology to nonsterilized ones, regardless of the material. SS promoted exposition of smaller filler particles in both materials. Although sterilization methods did not alter surface roughness and wettability, the sterilization methods selectively altered the micromorphology of the materials tested. RESEARCH HIGHLIGHTS: This study's main finding suggests that each sterilization method altered the surface of glass ionomers in different ways. Thus, the choice of sterilization methods prior to bacterial adhesion can lead to a bias in antimicrobial studies.

Fluoride release and surface roughness of a new glass ionomer cement: glass carbomer

Abstract Objective This study analyzed the fluoride release/recharge and surface roughness of glass carbomer compared to other encapsulated glass ionomer cements (GICs). Material and method The GICs tested were Glass Fill® (GC-GCP Dental), Riva Self Cure® (RS-SDI), Riva Light Cure® (RL-SDI), Equia Fil® (EF-GC Europe). The composite resin Luna® (LU-SDI) was used as control. Five samples of each material were prepared and kept in a humidifier for 24 hours (37 °C, 100% relative humidity). Fluoride release was measured in two times: before (T1: days 1, 2, 7, 14) and after topical application of fluoride (T2: days 15, 16, 21 and 28). The surface roughness was also measured in both times (T1: days 1 and 14; T2: days 15 and 28). All samples were submitted to a single topical application of acidulated fluoride phosphate (Fluor Care - FGM). Two-way ANOVA with repeated measures and Tukey's post-test (p &lt;0.05) were used in the statistical analysis. Result Equia Fil presented the highest fluoride release in both evaluation periods, with a higher release in T1 (p &lt;0.05). The other materials tested, including glass carbomer presented similar release in both periods (T1 and T2). Regarding surface roughness, no significant differences were observed in the interaction between the material × time factors (T1 and T2) (p=0.966). Conclusion The GICs tested presented fluoride release and recharge ability and showed no surface roughness increase by topical application of fluoride.

Análise da dureza de um novo material restaurador para ART: Glass Carbomer

Resumo Objetivo Este estudo avaliou a microdureza de dois materiais ionoméricos – Glass Carbomer (GC-GCP Dental) e Riva Light Cure (RL-SDI) ‒ em combinação com quatro unidades fotopolimerizadoras (Carbo LED lamp, GCP-Dental; Demi LED curing light, Kerr; Poli Wireless, Kavo; Radii Plus, SDI). Material e método Foram confeccionados 80 corpos de prova seguindo a orientação dos fabricantes, sendo 40 para cada material ionomérico e, para cada 10 corpos de prova, uma das unidades fotopolimerizadoras foi utilizada. Após sete dias de armazenamento em água destilada e temperatura ambiente, os 80 corpos de prova foram submetidos ao teste de microdureza Vickers (microdurômetro HMV 2T). Cinco indentações foram realizadas em cada corpo de prova (centro, extremidades direita e esquerda, e superior e inferior). O ensaio foi realizado sob uma carga de 100 gramas, com tempo de penetração de dez segundos. Resultado Independentemente da unidade fotopolimerizadora, o Riva Light Cure (RL-SDI) apresentou menor microdureza que o material Glass Carbomer (GC-GCP-Dental). A microdureza do Glass Carbomer (GC-GCP-Dental) foi influenciada pelo tipo de unidade fotopolimerizadora utilizada como fonte de calor. A análise de variância e o Teste de Tuckey (p&lt;0,05) mostraram que a interação dos fatores ‘material’ vs. ‘unidade fotopolimerizadora’ (p&lt;0,001) e os fatores principais ‘material’ (p&lt;0,001) e ‘unidade fotopolimerizadora’ (p=0,002) foram estatisticamente significantes. Conclusão O material ionomérico Glass Cabomer (GCP- Dental) apresentou valor de microdureza significativamente superior quando comparado com o cimento de ionômero de vidro modificado por resina Riva Light Cure (SDI), independentemente da unidade fotopolimerizadora utilizada.

The Effect of Resin-modified Glass-ionomer Cement Base and Bulk-fill Resin Composite on Cuspal Deformation.

This study investigated cuspal deformation in teeth restored with different types of adhesive materials with and without a base. Mesio-occluso-distal slot cavities of moderately large dimension were prepared on extracted maxillary premolars (n=24). Teeth were assigned to one of four groups and restored with either a sonic-activated bulk-fill resin composite (RC) (SonicFill), or a conventional nanohybrid RC (Herculite Ultra). The base materials used were a flowable nanofilled RC (Premise Flowable) and a high-viscosity resin-modified glass-ionomer cement (RMGIC) (Riva Light-Cure HV). Cuspal deflection was measured with two direct current differential transformers, each contacting a buccal and palatal cusp. Cuspal movements were recorded during and after restoration placement. Data for the buccal and palatal cusp deflections were combined to give the net cuspal deflection. Data varied widely. All teeth experienced net inward cuspal movement. No statistically significant differences in cuspal deflection were found among the four test groups. The use of a flowable RC or an RMGIC in closed-laminate restorations produced the same degree of cuspal movement as restorations filled with only a conventional nanohybrid or bulk-fill RC.

The effect of different organic solvents on the degradation of restorative materials.

Objective:To evaluate the solubility of three restorative materials exposed to the different endodontic solvents.Materials and Methods:The organic solvents eucalyptus oil, xylol, chloroform, and orange oil, with distilled water as the control group was utilized. The restorative materials light-cured resin (Filtek Z250/3M ESPE), light-cured-resin-reinforced glass ionomer (Riva Light Cure LC/Southern Dental Industries SDI]) and resin-modified glass ionomer (Vitremer/3M ESPE) were analyzed. A total of 50 disks containing specimens (2 mm × 8 mm Ø) were prepared for each of the three classes of restorative materials, which were divided into 10 groups (n = 5) for immersion in eucalyptus oil, xylol, chloroform, orange oil or distilled water for periods of either 2 min or 10 min. The means of restorative material disintegration in solvents were obtained by the difference between the original preimmersion weight and the postimmersion weight in a digital analytical scale. Data were statistically analyzed by two-way analysis of variance while the difference between the materials was analyzed by Student-Newman-Keuls test. The significance level set at 0.05.Results:Vitremer showed the highest solubility, followed by Riva LC, and these were statistically different from eucalyptus oil, xylol, chloroform, and distilled water (P < 0.05). Regarding the immersion time in solvents, there were no significant differences between the two tested periods (P > 0.05).Conclusions:The solvents minimally degraded the composite resin, although they did influence the degradation of both resin-modified glass ionomer resin and resin reinforced with glass ionomer.

Effect of bonding application time on the microleakage of Class V sandwich restorations

The aim of this study was to assess the effect of bonding application time on the microleakage of Class V sandwich restorations. Eighty non-carious third molars were randomly divided into 16 groups. Two Class V cavities were prepared on the buccal and lingual surfaces of teeth. Three groups were restored with Fuji II GIC and treated with a total-etch bonding system (Stea/SDI) immediately after insertion, at 7 minutes and 15 minutes after mixing the glass ionomer cements (GICs). Another three groups were restored with Riva Self Cure GIC and treated with the total-etch system identically. The other six groups were subjected to self-etching bonding (Frog/SDI) after GIC placement in an identical procedure. The remaining groups were made using light cure GICs (Fuji II or Riva Light Cure) in conjunction with the total-etch or self-etching systems. Cavities were then restored with composite (Valux plus, 3M/ESPE). Samples were subsequently immersed in 2% methylene blue solution for 48 hours and observed under a stereomicroscope after sectioning. Four-scale grading was used to assess microleakage in occlusal and gingival walls. Data were analysed using Kruskal-Wallis and Mann-Whitney tests. The self-etching bonding system exhibited more microleakage in occlusal margins regardless of time. Over time, microleakage significantly decreased in gingival margins in all self-cure groups except for Riva Self Cure treated with the total-etch system (p < 0.05). Bonding application time had no effect on the microleakage of occlusal margins. However, maturation of GICs induced a decreased microleakage in gingival margins.