Surface Sealant Effect on the Color Stability of a Composite Resin Following Ultraviolet Light Artificial Aging

Coating Agents for Resin Composites: Effect on Color Stability, Roughness, and Surface Micromorphology Subjected to Brushing Wear

This study evaluated the influence of six resin composite coating agents on color stability and surface roughness after toothbrushing abrasion. Discs (Ø6 mm x 2 mm) of nanofilled resin composite (Filtek Z350XT) were prepared for application of coating agents (n=10): control (absence), two surface sealants (PermaSeal and BisCover LV), two adhesive systems (Scotchbond Multi-Purpose Adhesive/3M Oral Care and Single Bond Universal), and two modeling liquids (Modeling Resin and Composite Wetting Resin). CIELab*, WID, and color change (ΔEab, ΔE00, and ΔWID) were analyzed at baseline, after finishing and polishing, after application of coating agents, after coffee staining (simulating 30 days and one year of staining), and after toothbrushing abrasion. Roughness evaluations (Ra) were performed at the initial time point, after finishing and polishing, after application of coating agents, and after toothbrushing abrasion. Surface micromorphology was evaluated (2,000×) before and after toothbrushing abrasion. Generalized linear mixed models or Kruskal-Wallis and Dunn tests (α=0.05) showed that L* decreased significantly (p<0.0001) and a* increased significantly in all the groups after staining (p<0.0001). After toothbrushing, Modeling Resin showed higher ΔEab and ΔE00 than the control, Scotchbond Multi-Purpose Adhesive, Composite Wetting Resin, PermaSeal, or BisCover LV (p<0.0001). There was a significant increase in roughness for Composite Wetting Resin, Modeling Resin, and PermaSeal after application of the agents (p<0.05), but a significant decrease for BisCover LV (p<0.05), which achieved high surface smoothness. After abrasive wear, BisCover LV showed the lowest roughness values among all agents. Composite Wetting Resin and Modeling Resin showed higher roughness than the other groups (p<0.05), and surface irregularities. In conclusion, the coating agents did not prevent coffee staining, and they also led to increased surface roughness, with only BisCover LV providing greater surface smoothness after toothbrush abrasion.

Effect of Photoaging on the Structure, Optical Properties and Roughness of One-Shade Composite Restoratives

The aim of the study was to evaluate changes in the degree of C=C conversion (DC%), chemical structure, optical properties and roughness of one-shade composites before/after photoaging. Τhe one-shade materials tested were Charisma Topaz One (CHT), Clearfil Majesty ES-2 Universal (MES), Essentia Universal (ESU) and Omnichroma (OMN), with G-aenial Anterior (CNA) serving as control. Specimens (2 mm thickness) were prepared and tested for DC% and chemical structure (ATR-FTIR spectroscopy), optical properties (L*a*b*-ΔΕ, translucency parameter-TP, opalescence parameter-OP, contrast ratio-CR and total transmittance-TT by UV-Vis spectroscopy) and roughness (Sa, Sz, Sdr, Sds and Sc by optical profilometry) before and after photoaging (Xe-arc weatherometer). Significant differences were found in DC% between top-bottom surfaces (ESU, OMN before; ESU, CNA after). Photoaging improved DC%, reduced ester peaks implying photodegradation, reduced L* (CHT, OMN, CNA), a* (CHT, CNA), b* (OMN, CNA), TP (all, except for MES), OP (only MES), CR (only MES, but an increase in CNA) and TT (CHT, OMN). OMN, CNA and MES demonstrated ΔΕ > 3.3. Photoaging significantly increased all roughness parameters in all materials, except for MES (Sz, Sdr, Sc) and OMN (Sdr). Although listed in the same group, significant differences were found in one-shade composites before and after photoaging. Several products were strongly affected by photoaging, demonstrating evidence of photodegradation, an increased roughness and color changes exceeding the clinically acceptable levels.

Influence of surface sealants on the quality of posterior restorations with bulk-fill composites: A 4-year randomized clinical trial

OBJECTIVES

The aim of this study was to evaluate the clinical performance of surface sealants associated with a bulk-fill composite in posterior restorations after 4 years.

METHODS

A total of 174 posterior restorations were performed on 57 participants using a self-etch adhesive system and a bulk-fill composite. The groups were then divided into the following categories: 1) without surface sealant (NoS), 2) with surface sealant Biscover (Bisco, SBi), and 3) with surface sealant Permaseal (Ultradent, SPe). Restorations were evaluated using FDI criteria at baseline and after 1 and 4 years. Statistical analysis was conducted using Kaplan-Meier survival analysis and the Chi-square test (α = 0.05).

RESULTS

After 4 years, only one restoration was lost (1 in the NoS group). The fracture/retention rate (with 95% confidence interval) was 98% for NoS and 100% for both SBi and SPe (p = 0.76). The majority of secondary outcomes showed minor defects, with no significant differences among the groups (p > 0.05). However, significant differences were observed among the groups in terms of marginal staining and marginal adaptation (p = 0.03). In both items, twelve restorations (nine in NoS, one in SBi, and two in SPe) showed minor marginal discrepancies favoring the sealant groups (SBi and SPe).

SIGNIFICANCE

Regardless of the use of surface sealants, the bulk-fill composite restorations showed excellent clinical performance after 4 years. However, the groups that received sealants showed better marginal adaptation and less marginal discoloration compared to those that did not receive sealants.

Discrimination between Zingiberis Rhizoma Praeparatum and carbonised ginger by colour measurement and fingerprint analysis

INTRODUCTION

Zingiberis Rhizoma (ZR) has been used as a traditional Chinese herb and culinary food for thousands of years. Its two processed products, Zingiberis Rhizoma Praeparatum (ZRP) and carbonised ginger (CG), possess different therapeutic effects.

OBJECTIVES

To establish an objective and comprehensive method to differentiate ZRP from CG and to evaluate their qualities.

METHODOLOGY

Colour values of ZRP and CG were tested to establish the colour models by spectrophotometry. Moreover, high-performance liquid chromatography (HPLC) was developed for fingerprint and quantitative analysis, and chemometric approaches were applied to discriminate between ZRP and CG. Finally, Spearman's correlation analysis was performed to investigate the relationship between the colour values and the peak areas of the common chemical compositions.

RESULTS

Colour reference ranges of colour parameters and mathematical functions were built to distinguish ZRP from CG. In fingerprint analysis, 26 common peaks were detected in these two processed products, among which 6-gingerol, 8-gingerol, 6-shogaol, 10-gingerol, 8-shogaol and 10-shogaol were identified. Meanwhile, ZRP could be differentiated from CG by chemometrics analysis. In addition, the correlation between colour parameters and common peak areas was found and the contents of 6-gingerol, 8-gingerol, 6-shogaol, 10-gingerol, and 8-shogaol were determined simultaneously.

CONCLUSIONS

An objective approach of colour measurement, HPLC fingerprint coupled with chemometrics analysis and quantitative assessment could be applied to discriminate ZRP from CG and evaluate the qualities of ZRP and CG rapidly.

Can the use of surface sealant on restorative materials prevent discoloration related to iron syrup supplements?

PURPOSE

The purpose of this study was to evaluate the impact of surface sealants on the stain resistance of restorative materials exposed to iron syrups.

METHODS

Sixty specimens were prepared from each of three restorative materials-compomer (Dyract XP), a microhybrid composite (Filtek Z250), and a nanohybrid composite (G-aenial Anterior). Specimens were divided into three solution groups (n = 20) and immersed in two iron syrups (Ferrum and Ferro Sanol B) and distilled water. Two subgroups, sealed (BisCover ( +)) and unsealed (BisCover (-)), were established for each group (n = 10). Color changes between baseline and measurements at 4, 8, 24, 48, and 72 h were calculated with CIEDE2000 (ΔE₀₀) metrics. Data were analyzed with 4-factor mixed-design ANOVA.

RESULTS

The first null hypothesis of this study that the use of surface sealant would not mitigate the restorative materials' susceptibility to staining was rejected: significant differences were found between BisCover ( +) and BisCover (-) groups in ΔE00 values for all restorative materials tested in Ferro Sanol B (p < 0.001) and Ferrum (p = 0.002) solutions. The ΔE₀₀ values in the Ferro Sanol B/BisCover ( +) groups were significantly lower than in Ferrum/BisCover ( +) groups (p = 0.002), the second null hypothesis that different forms of iron syrups would not impact the staining resistance of restorative materials was rejected. ΔE₀₀ values were different for each restorative materials tested, the third null hypothesis that the type of restorative material would not affect staining resistance was rejected.

CONCLUSIONS

The application of surface sealant significantly improved the color stability of restorative materials. The content of iron syrups was also an important factor affecting color change. Nanohybrid composites seem to be more resistant to the staining effects of iron syrups.

Effect of different placement techniques on color stability and surface roughness of resin composites

Abstract Introduction Longevity and clinical success of dental restorations can be influenced by many factors during the restorative procedures. Objective This study aimed to evaluate the influence of different placement techniques on color stability and surface roughness of two resin composites. Material and method The groups of specimens (n=10) were divided according to resin composite (FiltekTM Z250 XT and FiltekTM Z350 XT) and placement technique: Mylar strip, spatula, dry brush, modeling liquid, and surface sealant. Color stability and surface roughness were accessed using a spectrophotometer (CIELab color space) and a rugosimeter (standard cutoff of 0.8 mm), respectively, after water storage. Subsequently, the specimens were immersed in coffee for 48 h and final color was measured. The data were analyzed using ANOVA and the Tukey’s post hoc test (α=5%) and the correlation between surface roughness (Ra) and color change (∆Eab) was assessed using the Pearson’s correlation coefficient. Result The different placement techniques influenced Ra and ∆Eab on both resin composites. The groups treated with surface sealant showed greater difference in ∆Eab for both resin composites. The FiltekTM Z250 XT resin showed greater color stability compared with the FiltekTM Z350 XT resin regardless of the placement technique used. Ra of each placement technique was similar among the resin composites except for the FiltekTM Z350 XT modeling liquid group, which presented lower Ra values compared with those of FiltekTM Z250 XT. A correlation between Ra and staining was identified (p=0.268). Conclusion Color stability and Ra are influenced by different placement techniques.

Quality assessment of raw and baked Aucklandia lappa Decne. by color measurement and fingerprint analysis

Aucklandia lappa Decne. has been used as a traditional Chinese herb for thousands of years in treating various kinds of disorders. According to the Chinese Pharmacopoeia, there are two kinds of processed products, raw and baked Aucklandia lappa Decne., which have different therapeutic effect in clinical application. In this study, based on color measurement and fingerprint analysis, the method to assess the quality of these two processed products was established. In color measurement, the reference ranges of color parameters (L^* , a^* , and b^* ), standard color difference values, and mathematical prediction functions of these two processed products were obtain after the color was measured by a spectrophotometer. Meanwhile, high-performance liquid chromatography fingerprints of these two processed products were established, where there were 12 peaks recognized as the common peaks in both processed products, in which two peaks were identified as costunolide and dehydrocostus lactone, and these two processed products were classified with chemometrics analysis subsequently. Furthermore, the correlation between color parameters and sample compositions was explored and the contents of costunolide and dehydrocostus lactone were determined simultaneously by high-performance liquid chromatography. Consequently, an integral method including color measurement, high-performance liquid chromatography fingerprint with chemometrics analysis, and quantitative determination was established.