Comparative evaluation of surface properties of enamel and different esthetic restorative materials under erosive and abrasive challenges: An in vitro study

Two-year clinical performance of indirect resin composite restorations in endodontically treated teeth with different cavity preparation designs: a randomized clinical trial

TRIAL DESIGN

This is a randomized, controlled, superiority, double-blinded, parallel-group, two-arms trial with an allocation ratio of 1:1. This study aimed to assess whether the cavity design could affect the clinical performance of the CAD/CAM generated indirect resin composite restoration in endodontically treated teeth (ETT) evaluated using the Modified USPHS criteria after a two-year follow up.

METHODS

A total of 30 participants who underwent endodontic treatment for MOD cavities in permanent molars were divided randomly into two parallel groups (n = 30 restorations) according to the performed cavity design to group 1 in which there was no cuspal reduction (inlay) and group 2 in which cuspal reduction was performed (overlay). All pulp chambers were filled with bulk fill flowable composite, and the cavities were prepared following the criteria of the cavities for indirect restorations and restored using nano-hybrid composite resin blocks (Brilliant, Coltene, Switzerland). The restorations were evaluated using the modified USPHS criteria at baseline, six months, one-year and two years follow-up visits. For qualitative data, frequencies (n) and percentages (%) were used to display the data, while mean and standard deviation (SD) were used for quantitative data. The normality of the data was evaluated using the Shapiro-Wilk and Kolmogorov-Smirnov tests. For every test, P ≤ 0.05 was used as the significance threshold.

RESULTS

Twenty-six individuals completed the follow-up period after receiving the assigned intervention.The inter-group comparison showed that, at the 6- months and 12- months observation points, the overlay design had significantly better marginal adaptation, less incidence of discoloration or tooth/restoration fracture, and similar marginal integrity and caries incidence to the inlay design. After 24- months, the overlay design still had better marginal adaptation, less incidence of discoloration or tooth/restoration fracture and less caries incidence in comparison to the inlay design, while there was no difference in the marginal integrity between either design.

CONCLUSIONS AND CLINICAL RELEVANCE

Cuspal reduction in endodontically treated teeth showed better clinical performance than the cusp preservation thus, the former is more reliable.

A Comparative Evaluation of the Remineralization Potential of Two Contemporary Bioactive Glass-containing Dentifrices on Artificially Demineralized Human Enamel: An In Vitro Study

Background

There is limited literature comparing the remineralization potential of these two dentifrices, Elsenz™, which contains fluoro calcium (Ca) phosphosilicate, and Shy-NM™, which contains Ca sodium phosphosilicate, are a few of the remineralizing agents.

Aim

To assess and compare the remineralization potential of Elsenz™ and Shy-NM™ dentifrices on artificially induced carious lesions on permanent teeth, using the Vickers microhardness measuring method and scanning electron microscope (SEM) connected to energy dispersive X-ray analysis after laboratory stimulation of the oral environment employing the pH cycling model.

Materials and methods

A total of 30 sound human premolar teeth were divided into six groups for both parameters. Group I-Elsenz™ dentifrice, group II-Shy-NM™ dentifrice, and group III-control. The surface microhardness (SMH) of the test specimens was evaluated followed by a scanning electron microscope with energy dispersive analysis (SEM-EDAX). The specimens were tested at baseline, demineralization, and remineralization. The collected data were subjected to statistical analysis.

Results

Surface microhardness following remineralization with Elsenz™ was 359 Vickers hardness number (VHN), and with Shy-NM™ was 312 VHN. Elsenz™ showed significantly higher remineralization compared to Shy-NM™ (p = 0.002). The SEM-EDAX of the tooth specimens after remineralization revealed an increase in the Ca weight percentage (wt%) compared with demineralization values, which was statistically significant for both Elsenz™ (45.95 ± 3.55%) and Shy-NM™ (47.24 ± 1.99%), along with an increase in the phosphorus wt%, which was statistically significant for Elsenz™ (20.25 ± 0.95%) compared to Shy-NM™ (19.95 ± 0.59%).

Conclusion

Within the scope of this study, the incorporation of fluoride in bioactive glass (BAG) in Elsenz™ had the potential to remineralize enamel better than Shy-NM™ dentifrice. It can, therefore, be concluded that Elsenz™, when compared with Shy-NM™, would be effective in inhibiting demineralization.

How to cite this article

Thoutam SV, Kumar S, Naidu J. A Comparative Evaluation of the Remineralization Potential of Two Contemporary Bioactive Glass-containing Dentifrices on Artificially Demineralized Human Enamel: An In Vitro Study. Int J Clin Pediatr Dent 2024;17(4):451-455.

Effect of Low pH Dietary Supplements on Discoloration of Resin Composites

AIM

This study aimed to evaluate the impact of the consumption of low pH dietary supplements on the color stability of different resin composites.

MATERIALS AND METHODS

Three different restorative materials were used for this in vitro study: Filtek One Bulk-Fill (FOB), Filtek Z550 (Z550), and Fill-Up (FUP). Samples fabricated from each composite group were divided into four subgroups, and color measurements were performed at baseline. The control subgroup was stored in distilled water, and the other three subgroups were immersed in acidic dietary supplement solutions (Redoxon, Supradyn, and Voonka Collagen Shake) for 2 minutes daily for 28 days. Color measurements were obtained using a digital spectrophotometer. Color change values (ΔE1) were calculated after each color measurement. Next, all samples were immersed in a coffee solution for 7 days and repeat color measurements were taken to determine ΔE2 values. The study groups were compared using the Kruskal-Wallis test (α =0.05).

RESULTS

ΔE1 values were significantly different among the groups (P < 0.05). While Voonka Collagen Shake produced the greatest discoloration in FOB (1.67 ± 1.08) and Filtek Z550 (3.59 ± 1.90) materials, Fill-Up showed the highest discoloration (3.14 ± 0.37) with Supradyn. Analysis of ΔE2 values demonstrated a significant difference only for the Filtek Z550-Redoxon group versus the control group (P < 0.05).

CONCLUSION

Acidic dietary supplements not only produce color alterations in resin composites but also reduce the staining resistance of the composite further, depending on the type of composite and dietary supplement. Consumption of staining food after taking Redoxon effervescent tablets produces greater discoloration in Filtek Z550 restorations compared with other restorative materials.

Effects of Different Toothpastes on the Nanomechanical Properties and Chemical Composition of Resin-Modified Glass Ionomer Cement and Composite Resin Restorations

PURPOSE

This study evaluates the effects of different toothpastes on the nanohardness and chemical compositions of restorative materials and dental surfaces.

METHODS

Bovine enamel (n = 72) and dentin (n = 72) blocks were obtained and restored using RMGIC (n = 36) or CR (n = 36) to create the following surfaces: dentin adjacent to RMGIC (DRMGIC), enamel adjacent to RMGIC (ERMGIC), dentin adjacent to CR (DCR), and enamel adjacent to CR (ECR). After restoration, one hemiface of each specimen was coated with an acid-resistant varnish to facilitate the creation of control (C) and eroded (E) sides; the latter were achieved by erosion-abrasion cycles as follows: erosion with 1% citric acid: 5 days, four times for 2 min each day; 1% citric acid/abrasion, two times for 15 s, followed by immersion in a toothpaste slurry for 2 min. Toothpastes without fluoride (WF; n = 12), with sodium fluoride (NaF; n = 12), and with stannous fluoride (SnF₂; n = 12) were used for RMGIC or CR. The specimens were analyzed for nanohardness (H), and chemical composition using energy-dispersive X-ray spectroscopy and Raman microscopy. The data were statistically analyzed using two-way repeated measures ANOVA and Tukey's test (α = 0.05).

RESULTS

Lower H values were obtained with NaF for DRMGIC-C, with a statistically significant difference from the H value obtained with WF (p < 0.05). The calcium and phosphorus concentrations in DCR-E were significantly lower with WF than with the other types of toothpaste (p < 0.05). Fluoride-containing toothpastes are capable of preserving the main chemical components of the dentin adjacent to the restorative materials under erosive-abrasive conditions.

Deterioration of direct restorative materials under erosive conditions with impact of abrasion and attrition in vitro

Objective

To compare the cumulative impact of sequential wear on mechanical properties and appearance of a composite resin (CR), Filtek Z250^®, a glass ionomer GI, Fuji IX GP^®, and a glass hybrid (GH), Equia Forte^®.

Material and Methods

Six equally sized specimens of each material were subjected to wear tests, i.e., simulation of brushing, chewing and acidic liquid exposure, mimicking at least 6 months of clinical exposure. Surface roughness, hardness, substance loss and degree of shade lightness were determined.

Results

Following wear tests, significant increase in surface roughness and decrease in hardness values were observed for all materials (p < .05). Significantly larger substance loss was found in Equia Forte^® specimens compared to Filtek Z250^® (p < .05), while that of Fuji IX^® exceeded the measurement capacity of the instrument. Opposite to the two other materials, the shade of Filtek Z250^® became darker.

Conclusions

Sequential wear exposure mimicking abrasion, erosion and attrition to products representing CR, GI and GH, caused weakening and change in appearance of the materials. The composite resin was the most mechanically resistant to the sequential wear.

The Impact of Simulated Gastric Acid and Toothbrushing on Surface Characteristics of Resin-Modified Glass-Ionomer Cements

Background and Objectives: The aim of this in vitro study was to evaluate the effect of simulated gastric acid associated with toothbrushing on the surface condition of three resin-modified glass-ionomer cements (RMGIC). Materials and Methods: One hundred and sixty samples of each material were obtained and included in three study groups according to the tested material: Group I (Ionolux, VOCO GmbH, Cuxhaven, Germany); Group II (Vitremer, 3 M-ESPE, St. Paul, MN, USA); and Group III (Fuji II LC, GC Corporation, Tokyo, Japan). The samples were submersed in hydrochloric acid 0.01 M (pH 3.8) for 3 h and exposed to a toothbrushing procedure at a frequency of 10,000 cycles with medium and hard bristles immediately or 30 min after the acid attack. Profilometric measurements were performed by using a non-contact profilometer (Dektak XT, Bruker, Billerica, MA, USA) in order to assess the surface roughness. ANOVA and Bonferroni post hoc tests were used for the statistical analysis at a significance level of p < 0.05. Results: Exposure of RMGICs to the erosive effect of hydrochloric acid in association with toothbrushing 30 min after the chemical attack increased the surface roughness of all three RMGICs. Exposure of the three tested materials exclusively to the action of hydrochloric acid did not affect the surface roughness. Conclusions: One year of hydrochloric acid challenge associated with one year of toothbrushing with medium-hardness bristles performed 30 min after the acid attack increase the surface roughness of two of the three types of RMGIC tested (Ionolux and Fuji II LC).

Effects of Charcoal Toothpaste on the Surface Roughness, Color Stability, and Marginal Staining of Resin Composites

OBJECTIVE

This study was designed to evaluate the effects of charcoal toothpaste on the surface roughness, color stability, and marginal staining of resin composite restorations.

METHODS

A total of 100 bovine incisors was collected. The crowns were sectioned and randomly divided into 10 groups (n=10) according to two study factors: toothpaste groups and nanoparticle resin composite groups. Five toothpastes-Bianco Pro Clinical (Bianco Oral Care, Uberlândia, MG, Brazil) - Control group; Bianco Carbon (Bianco Oral Care); NAT, Natural Suavetex Carvão Ativado (Suavetex, Uberlândia, MG, Brazil); Nano Action Black Be Emotion (Polishop, Jundiaí, SP, Brazil); and BIW, Black is White (Curaprox, Curaden AG, Kriens, Switzerland)-and two resin composites-Z350XT, Filtek Z350XT (3M Oral Care) and Vittra, Vittra APS (FGM, Joinville, SC, Brazil)-were used. Circular cavities with a diameter of 4 mm and a depth of 1 mm were prepared on the buccal face of the tooth crowns and restored with resin composites. The specimens were subjected to three months of simulated toothbrushing. The surface roughness (right angle [Ra], in micrometers [μm]) of the resin composites was measured before and after toothbrushing in five areas per specimen. The resin composite color and luminosity changes (ΔE and ΔL, respectively) were measured using reflectance spectroscopy (Vita EasyShade). Macro photographs were taken before and after toothbrushing to qualitatively analyze the marginal staining (MSt) of the resin composite restorations. Scanning electron microscopy (SEM) was performed before and after the simulated toothbrushing. Ra data were analyzed using two-way analysis of variance with repeated measures and the Tukey HSD test; MSt was analyzed using Kruskal-Wallis and Dunn tests (α=0.05), and the resin composite color change was analyzed using the clinically unacceptable level of ΔE > 3.3.

RESULTS

Simulated brushing increased Ra irrespective of the resin composite or toothpaste used. No significant differences were found in Ra between the control group and all groups on which the charcoal toothpastes were tested. A clinically unacceptable level of resin composite color change (ΔE>3.3) was found after the use of most charcoal toothpastes. Use of Bianco Carbon resulted in marginal staining similar to that of the control group and was lower than that of the other charcoal toothpastes. Vittra brushed with black toothpaste showed the highest marginal staining.

CONCLUSION

Use of charcoal toothpaste resulted in Ra values of resin composites similar to those found with conventional toothpastes. Charcoal toothpaste generally resulted in clinical resin composite color changes (ΔE). All charcoal toothpastes, except Bianco Carbon, caused marginal staining of the resin composite restorations.

Effects of Simulated Gastric Acid Exposure on Surface Topography, Mechanical and Optical Features of Commercial CAD/CAM Ceramic Blocks

Gastric acid exposure produces tooth structure demineralization and dental ceramic degradation. The most affected patients are those who suffer from gastroesophageal reflux disease, bulimia nervosa, and pregnant women with prolonged severe nausea. In order to protect this kind of patient, the purpose of this study was to determine whether simulated gastric acid exposure leads to microstructural changes in surface topography, hardness, color changes, and translucency of some ceramic materials, which are already on the market. Forty disks (Triluxe Forte, Cerasmart, Enamic and Empress CAD) were analyzed before and after immersion in simulated gastric acid juice, in terms of microhardness, surface roughness, translucency, and surface morphology using scanning electron microscopy. Color change was assessed by using a spectrophotometer based on CIELab parameters and the results showed that, after exposure, ∆Eab remained under the threshold of acceptability and perceptibility. In terms of microhardness, Cerasmart is the only material that did not undergo changes after immersion. SEM images illustrated observable changes surface topography after acid exposure for all the tested materials. In conclusion, Triluxe Forte suffered the most important changes after simulated gastric acid juice exposure, and Cerasmart proved to be the least affected material.

Effect of Different Herbal Tea Preparations on the Color Stability of Glass Ionomer Cements

Objective

To compare the color stability of the newer glass ionomer cements (GIC) when exposed to “Green tea” (GT), “Tulsi tea” (TT), and “Areca tea” (AT) using spectrophotometric analysis.

Materials and Methods

We selected commercially available GC Fuji IX GP EXTRA and Ketac Universal for this study. Eighty disc-shaped samples were made using a mold, which were immersed in the freshly prepared test solutions (distilled water, GT, TT, and AT) for 15 minutes per day for 60 days. The color estimation was done using a spectrophotometer.

Results

GC Fuji IX samples had a significantly higher mean difference in ΔE value than Ketac Universal when immersed in GT, AT, and control (P<0.001, 0.018, and <0.001), respectively. With GC Fuji IX, GT and AT stained more than TT and control solutions. Samples of Ketac Universal showed a significantly higher mean difference in ΔE values when immersed in AT, followed by GT, TT, and control.

Conclusion

Within the study’s limitations, we conclude that both the GICs exhibited staining over time on exposure to all the test solutions. Ketac Universal demonstrated lower staining potential than GIC Fuji IX GP Extra for GT and AT.

Influence of simulated gastric juice on surface characteristics of CAD-CAM monolithic materials

STATEMENT OF PROBLEM

How the surfaces of monolithic esthetic restorations behave in the presence of acidic substances is unclear.

PURPOSE

The purpose of this in vitro study was to evaluate the effect of simulated gastric juice on roughness, morphology, microhardness, substance loss, and color change of computer-aided design and computer-aided manufacturing (CAD-CAM) monolithic materials.

MATERIAL AND METHODS

Disks from Lava Ultimate, VITA ENAMIC, IPS e.max CAD, and VITA SUPRINITY were analyzed for roughness, morphology, and microhardness by using a confocal microscope, scanning electron microscope (SEM), and Vickers hardness tester. Substance loss was determined by weighing the specimens on an analytical balance, and color change (ΔE) was assessed by using a spectrophotometer based on the CIELab parameters. All analyses were carried out before and after acid exposure.

RESULTS

Acid exposure significantly decreased the roughness, having a very high effect size on this property. The material was highly decisive in determining the microhardness, presenting the following order: VITA SUPRINITY>IPS e.max CAD>VITA ENAMIC>Lava Ultimate. The mass was not significantly affected by the acidic challenge. No significant difference in ΔE was found between Lava Ultimate and VITA ENAMIC and between IPS e.max CAD and VITA SUPRINITY. Lava Ultimate showed a higher ΔE than IPS e.max CAD and VITA SUPRINITY, whereas VITA ENAMIC exhibited higher ΔE only when compared with VITA SUPRINITY. All materials presented ΔE<1.

CONCLUSIONS

The simulated gastric juice significantly influenced the roughness of all the evaluated materials and promoted a color change classified as clinically undetectable in all materials.

Effects of dentifrices on mechanical resistance of dentin and restorative materials after erosion and abrasion

The aim of this study was to evaluate the mechanical resistance of dentin and restorative materials submitted to erosive/abrasive challenges with different dentifrices. The dentin was restored using a resin-modified glass-ionomer (RMGIC) or a composite resin (RC). One hemiface of the sample was protected, and the other was subdivided according to the applied dentifrice (n = 10): without fluoride (SF), sodium fluoride (NaF) and stannous fluoride (SnF). The specimens were submitted to erosive/abrasive cycles, the varnish was removed, and the Martens hardness (HMV) and elastic modulus (Eit) were evaluated. The data were analyzed by repeated two-way ANOVA measurements and Tukey tests (alpha = 0.05). When analyzing the HMV on the test side, there was no influence of the dentifrices in the dentin; however, the orders of NaF < SnF = SF in RC and SnF > NaF = SF in RMGIC were observed. Comparing the treated surfaces, there were no differences in the dentin, and only the SF since CR presented an HMV superior to that of RMGIC. Comparing control and test sides, both dentins obtained a decreased HMV after the erosive/abrasive challenge; for the restorative materials, superior values were found only for SnF in the RMGIC. The Eit values were influenced more by the dentifrices on the test side for the dentin adjacent to the RMGIC, with the lowest values shown for the SF, and for both materials, the highest values were shown for the SnF group. No differences were found when comparing each dentin treated with the same dentifrice; however, the RMGIC presented a superior Eit than the CR when brushed with both dentifrices with a fluoride. Comparing the control and test sides, the same results were obtained for the HMV. The dentifrices showed little influence on the dentin substrate, whereas the dentifrice with SnF enhanced the mechanical properties of the restorative materials, which was more evident in the RMGIC.