Comparative evaluation of fluoride release and recharge potential of novel and traditional fluoride-releasing restorative materials: An in vitro study

A comparative evaluation of fluoride release and rechargeability in conventional GIC (type II), pediatric GIC (type IX), and Cention-N: an in vitro study

PURPOSE

A comparative evaluation of fluoride release and re-chargeability in conventional glass ionomer cement (GIC) (type II), Pediatric GIC (type IX), and Cention-N-an in vitro study at an interval of first, fourteenth, and twenty first days.

METHODS

Three groups of test materials, each with twenty samples, were prepared. Measurements of the cumulative fluoride release [parts per million (ppm)] and re-release measured on the first, fourteenth, and twenty first days. Analysis of variance (ANOVA) was used to compare the means for different readings, and Tukey's post hoc analysis was used to compare each group with each other.

RESULTS

Initial and subsequent fluoride release of Cention-N at days one, fourteen, and twenty-one were all noticeably higher than those of conventional and pediatric GIC.

CONCLUSION

Compared to the Conventional and Pediatric GIC restorative materials, Cention-N was more effective in the initial and fluoride re-release.

Fluoride exchange by glass-ionomer dental cements and its clinical effects: a review

The topic of fluoride release and uptake by glass-ionomer (glass polyalkenoate) dental cements is reviewed. The study was based on a literature search carried out using PubMed. The main key words used were glass-ionomer and fluoride, and further refinements were made by adding the keywords anti-microbial, anti-caries and remineralization. Papers were selected from the initial search, which concentrated on fundamental aspects of fluoride release, including kinetics and the influence of the cement composition, and resulting clinical performance against caries. Other relevant papers were cited where they added useful and relevant data. From these published papers, it was possible to explain the detailed mechanism of fluoride release by glass-ionomer cements and also its uptake. Fluoride release has been shown to be a two-step process. In neutral solutions, the steps can be divided into early wash-out and long-term diffusion. In acid conditions, the early wash-out remains, though with greater amounts of fluoride released, and the long-term release becomes one of slow dissolution. The effect of fluoride on the viability of oral micro-organisms has been described, and glass-ionomers have been shown to release sufficient fluoride to reduce the size and viability of adjacent populations of oral bacteria. The effect of low levels of fluoride on the remineralization of tooth tissue has been considered. Levels needed to increase remineralization are much lower than those needed to adversely affect oral bacteria, from which we conclude that glass-ionomers release sufficient fluoride to promote remineralization. Despite this, there remains uncertainty about their overall contribution to sound oral health, given the widespread use of other sources of fluoride, such as toothpastes.

Antibacterial Activity and Biofilm Inhibition of New-Generation Hybrid/Fluoride-Releasing Restorative Materials

The antibacterial activity, and the effect of the application of additional topical fluoride on the bacterial activity, biofilm formation, and surface roughness of new-generation hybrid/fluoride-releasing materials were investigated. Two hundred and forty specimens were prepared in split Teflon molds (8 × 2 mm) from a resin composite (as negative control: G-aenial A’Chord/GC), Equia Forte HT Fil(GC), Equia Forte HT Fil+Equia Forte Coat, Riva Self-Cure (SDI), Riva Self-Cure+Equia Forte Coat, Zirconomer (Shofu), Beautifil II (Shofu), and Riva Silver (Shofu). Penicillin G,1U was used as positive control. The antibacterial activity was evaluated by the agar diffusion test immediately after the materials set using Streptococcus mutans (S. mutans) and Lactobacillus casei (L. casei), and repeated after application of 0.20% w/w (900 ppm) topical fluoride. The biofilm formation of S. mutans on each material was quantified by crystal violet staining. Surface roughness of the specimens was measured by a profilometer. The data were analyzed by Kruskal–Wallis, Dunn’s, one-way ANOVA, and Tukey’s HSD tests (p < 0.05). None of the tested restorative materials showed antibacterial activity and no inhibition zones were observed after treatment of the restoratives with additional topical fluoride. There were significant differences among the groups in terms of biofilm formation (p < 0.005). Equia Forte HT Fil with and without coating showed the lowest, while Riva self-cure without coating and Zirconomer showed the highest biofilm accumulation. None of the new-generation hybrid/fluoride-releasing materials demonstrated antibacterial activity and additional topical fluoride application did not make any change. Biofilm formation of the tested materials differed. All tested materials showed different surface roughness values (p < 0.005). Characteristics and compositions of the materials seemed to be more effective than the surface roughness.

An alkasite restorative material effectively remineralized artificial interproximal enamel caries in vitro

OBJECTIVE

To evaluate the remineralization of artificial interproximal enamel caries (AIEC) adjacent to alkasite, high viscous glass ionomer cement (HVGIC), and resin composite in class II restorations.

MATERIALS AND METHODS

Human enamel specimens were randomly assigned to 3 groups (n = 22): Filtek™ Z350, EQUIA Forte^®, and Cention N^®. The baseline hardness was determined using a Knoop microhardness assay. AIEC was formed in the specimens, and they were placed in contact with the proximal restorative materials then subjected to a 7-day pH cycling. Microhardness was determined post-artificial caries formation and post-pH cycling. The differences in the percentage of surface hardness recovery (%SHR) between the groups were compared using the Kruskal-Wallis test. The Dunn's test was used for between-group comparisons (p < 0.05). Specimen surface morphology was evaluated using scanning electron microscopy (SEM), and the calcium, phosphorus, and fluoride contents were analyzed by energy-dispersive spectroscopy (EDS). ANOVA with the post hoc Tukey multiple comparison test was used to evaluate the differences between groups (p < 0.05).

RESULTS

The Cention N^® %SHR was the highest, followed by EQUIA Forte^®, and Filtek™ Z350. There was a significant difference in the %SHR between Cention N^® and Filtek™ Z350 (p < 0.05). In contrast, there were no significant difference between Cention N^® and EQUIA Forte^®. Significantly increased enamel surface fluoride content was observed in the Cention N^® compared with Filtek™ Z350 specimens (p < 0.05). The SEM image of the Cention N^® specimens demonstrated the greatest mineral deposition.

CONCLUSIONS

Cention N^® markedly increased the surface hardness and fluoride content of adjacent AIEC compared with Filtek™ Z350 restorations.

CLINICAL RELEVANCE

Cention N^® is a promising alternative restorative material to remineralize initial enamel lesions in approximal adjacent surfaces, especially in high-risk caries patients.

Comparative evaluation of fluoride release and re-release and recharge potential of Zirconomer Improved and Cention

Background

The cariostatic action associated with fluoride-releasing restorative materials is mainly attributed to a sustained release of fluoride. This research aims on comparing Cention N and Zirconomer Improved in vitro fluoride release and re-release.

Methods

Test materials were grouped into two categories containing 15 samples each. The cumulative fluoride release and re-release measurements was made during 1st, 7th and 15th day. The independent sample t-test and paired t-test was used to check mean differences. The level of significance was kept at p<0.05.

Results

At day 1, 7 and 15 the initial fluoride release of zirconomer group was significantly higher (p<0.05) than the cention group. It was found that from day 1 to day 7 the mean initial fluoride release has significantly reduced (p<0.05) for both the groups. Similar results were also seen when comparisons were done between day 7 to day 15 (p<0.05) and day 1 to day 15 (p<0.05) for both the groups.

Conclusion

Zirconomer was more efficient in initial and fluoride re-release than the Cention N restorative material. Further in vivo studies with more parameters are recommended to evaluate fluoride release and cariostatic performance of Cention N and Zirconomer in real environmental circumstances.

In vitro wear of (resin-coated) high-viscosity glass ionomer cements and glass hybrid restorative systems

OBJECTIVES

The aim of the present study was to investigate the volumetric abrasive wear of a high-viscosity glass ionomer cement (hvGIC; Equia Fil) and a glass hybrid restorative system (ghRS; Equia Forte), each being recommended as amalgam alternatives. Both materials were applied with or without their respective resinous coating, and were compared with a conventional GIC (Ketac Fil) and a hybrid composite resin (CR; G-ænial Posterior).

METHODS

78 standardized occlusal Class I cavities were restored with the various materials (n = 13 per group). Before and after chewing simulation (30,000 cycles at 40 N), each sample underwent optical scanning procedures (Omnicam). A comparison of the total wear using a fluorescence-aided identification technique (OraCheck) followed, and differences (α = 5%) between groups were compared by means of MANOVA.

RESULTS

Regarding the wear rates of hvGIC and ghRS, no differences could be observed (p > .050), and this was not affected by the resinous coating. All hvGIC and ghRS restorations showed significantly higher abrasive wear than CR (p < .001), while the conventional GIC displayed a significant underperformance compared with any other material (p < .001).

CONCLUSIONS

Resinous coating of hvGIC or ghRS does not appear to exert an effective long-term protection against advanced abrasive wear. Compared to the conventional GIC showing a considerable substance loss, both hvGIC and ghRS materials revealed an improved abrasion resistance, but clearly failed to meet the excellent values of the CR.

CLINICAL SIGNIFICANCE

Occlusal loading should be carefully considered when using hvGIC or ghRS as amalgam (or composite resin) alternatives for the restoration of posterior teeth.