Comparison of Surface Roughness and Color Stability of Different Denture Characterizing Composite Resins: The Effect of Different Surface Treatments.

PURPOSE: This study aimed to investigate the effect of surface treatment and type of composite resin material on the color stability and surface roughness of different denture characterizing composites. MATERIALS AND METHODS: Two nanohybrids [Gradia Plus Gum, (GP) and SR Nexco Paste Gingiva, (SR)] and one microhybrid gingiva-colored composite resin [Amaris Gingiva, (AG)] were investigated. A total of 120 disk-shaped samples were prepared, 40 of each material. Samples were divided into two groups (n = 20) for each material according to the surface treatment applied: conventional polishing (control) and coated with a sealant in addition to the surface polishing. All groups were thermocycled. The surface roughness (Ra) was measured using a profilometer after thermal cycling. The samples were then divided into 2 subgroups (n = 10) and stored for 7 days in distilled water or coffee solution. Color differences (ΔE00 ) were calculated with a spectrophotometer. Results were evaluated with Kruskal-Wallis and Mann-Whitney U statistical analysis. RESULTS: The type of denture characterizing composite material and surface treatment method revealed statistically significant differences for the ΔE00 (after immersion both in coffee and distilled water) and the Ra values of denture characterizing composite (p < 0.001 for both). All sealed groups showed significantly higher Ra than the all polished groups. Both in the polished groups and the sealant applied groups, the GP had the highest mean Ra values (0.29 ±0.05 µm and 0.47 ±0.09 µm, respectively). It was followed by SR (0.23 ±0.06 µm and 0.41 ±0.10 µm, respectively), and AG groups (0.20 ±0.06 µm and 0.39 ±0.09 µm, respectively). According to the mean ΔE00 results, all composite groups showed significantly higher ΔE00 values immersed in coffee solutions compared to distilled water. In coffee solutions, the highest ΔE00 was observed in the polished GP (1.90 ±0.40), and the lowest ΔE00 was observed in the polished SR (0.97 ±0.36). The sealed groups showed higher ΔE00 than the polished groups, except for GP. CONCLUSIONS: The surface roughness value of sealant applied groups were significantly higher than those of the polished groups. The surface sealant application significantly increased the staining of all composite groups compared to conventional polishing, except for GP.

Effect of simulated tootbrushing on surface roughness of sealant agent coupled nanohybrid composite resins.

OBJECTIVE: To investigate the effect of toothbrushing on the surface roughness (Ra ) of different sealant agent coupled nanohybrid composite resins. MATERIALS AND METHODS: One hundred sixty disc-shaped (10 × 2 mm) specimens were prepared from four different nanohybrid composite resins (Z-550, Tetric EvoCeram, Clearfill Majesty, Ice). Specimen groups were divided into four subgroups for conventional polishing (control) and to apply three different surface sealant agents (Palaseal, Optiglaze, Biscover LV) (n = 10). The Ra values of the specimens were recorded before (Ra 0) and after 10,000 cycles of toothbrushing (Ra 1). The surface properties of the specimens were evaluated with scanning electron microscope (SEM). Data were statistically analyzed by two-way analysis of variance (ANOVA), Tukey HSD, and paired sample t tests. RESULTS: Composite resin material, surface treatment, and their interaction were significant on Ra values (p < 0.001). Significant decrease in Ra 0 values observed for surface sealant agent coupled Clearfill Majesty and Tetric EvoCeram composite resin groups compared with the control groups (p < 0.05). After simulated one-year toothbrushing, the control group of Clearfill Majesty had the highest Ra 1 value (p < 0.001). The Ra 1 values of all groups were significantly higher than the Ra 0 values (p < 0.05). CONCLUSIONS: Simulated 1-year toothbrushing increased the surface roughness of all nanohybrid composite resin materials. Optiglaze and Biscover LV sealant agents on Tetric EvoCeram, and all tested sealant agents on Clearfill Majesty enabled smoother surfaces than conventional polishing after toothbrushing. CLINICAL SIGNIFICANCE: Because toothbrushing increases the surface roughness of tested nanohybrid composite resins, the application of surface sealant agents on some of the tested resins can be considered for smoother surfaces.

Surface roughness and Streptococcus mutans adhesion on surface sealant agent coupled interim crown materials after dynamic loading.

BACKGROUND: With the application of surface sealant agents, smooth surfaces can be achieved in a shorter time when compared with conventional polishing. However, studies on the performance of these agents against chewing forces are not many. The purpose of this study was to evaluate the surface roughness and Streptococcus mutans adhesion on surface sealent coupled interim prosthetic materials after chewing simulation. METHODS: One hundred and twelve specimens were fabricated from two poly(methyl methacrylate) (Tab 2000, Dentalon Plus) and two bis-acryl (Tempofit, Protemp 4) interim crown materials and divided into 4 groups (n = 7) according to applied surface treatment: conventional polishing (control) and 3 surface sealant (Palaseal, Optiglaze, Biscover) coupling methods. The surface roughness values (Ra) were measured with a profilometer before (Ra0) and after aging through dynamic loading in a multifunctional chewing simulator for 10,000 cycles at 50 N load combined with integral thermocycling (between 5 and 55 °C) (Ra1). Specimens were incubated with Streptococcus mutans suspension and the total number of adherent bacteria was calculated by multiplying the counted bacterial colonies with the dilution coefficient. RESULTS: Surface sealant agent application significantly decreased the surface roughness compared with conventionally polished specimens, except for Optiglaze or BisCover LV applied Protemp 4 and Palaseal or Biscover LV applied Tempofit. Surface roughness after dynamic loading showed a statistically significant increase in all groups, except for the control groups of Tab 2000 and Protemp 4. A positive correlation was found between surface roughness values of interim prosthodontic materials and the quantitiy of Streptococcus Mutans. CONCLUSIONS: Even though surface sealant agent application significantly decreased the surface roughness compared with conventionally polished specimens, dynamic loading significantly increased the surface roughness of all surface sealant coupled materials. The Ra values of all test groups were higher than the plaque accumulation threshold (0.20 µm). Streptococcus mutans adhered more on rougher surfaces.

A quantitative and visual examination of sealed restorative specimens following exposure to artificial aging.

Low-viscosity polymer resins, or surface sealants (SSs), have been utilized as a means of finalizing the polishing step following the placement of composite resin restorations. The aim of this study was to measure the surface roughness (Ra) of composite resins treated with different SSs before and after exposure to an accelerated artificial aging protocol. The study included 5 experimental groups of composite resin discs (TPH Spectra ST) treated with different SSs (PermaSeal, Embrace WetBond Seal-n-Shine, OptiGuard, BisCover LV, and DuraFinish) and a control group consisting of untreated discs (n = 6 per group). The discs were prepared by inserting composite resin in 10 × 1-mm rings, covering the ring and material with a transparent strip, compressing the assembly between glass slides, and polymerizing through the slides on each side for 40 seconds with an LED curing light. Each disc except for the control specimens received a coating of the selected SS followed by application of a transparent matrix strip and then light polymerization for 20 seconds using an LED light source. Surface roughness measurements were obtained with a digital contact profilometer at baseline (immediately after polymerization) and following exposure to a thermocycling regimen to simulate aging. The data were analyzed using 2-way analysis of variance and post hoc Student-Newman-Keuls test with significance set at P < 0.05. There were no statistically significant differences among the groups at baseline. There were no statistically significant differences between the baseline and post-thermocycling Ra measurements except among the DuraFinish specimens, which were significantly rougher than all other groups after accelerated artificial aging. The use of SSs for the initial insertion and possibly for the long-term maintenance of composite resins could be minimally beneficial for restoration maintenance if a transparent covering medium is utilized during polymerization. However, due to the effects caused by formation of an oxygen-inhibited layer of unpolymerized monomers if a covering medium is not used, the results suggest the benefits do not offset the costs considering both gloss and Ra surface-testing parameters.

Influence of surface sealant and erosive challenge on the color change of composite resin subjected to artificial staining.

The aim of this study was to evaluate the influence of surface sealant and erosive challenge on the color change of composite resin after artificial staining with coffee. Forty-eight composite specimens (8 × 1 mm) were prepared and divided into 4 groups (n = 12) based on the timing of sealant application (immediate vs delayed) and exposure to acid (erosive challenge vs no challenge). The groups were subjected to the procedures in the following order: 1, sealant application, erosive challenge, color measurement, coffee immersion, and color measurement; 2, sealant application, color measurement, coffee immersion, and color measurement; 3, erosive challenge, color measurement, sealant application, coffee immersion, and color measurement; and 4, color measurement, sealant application, coffee immersion, and color measurement. In groups 1 and 2, surface sealant was applied immediately after preparation of the specimens. In groups 3 and 4, sealant was applied after the first color measurement. Color was measured with a spectrophotometer using the CIE L*a*b* system. The erosive challenge (groups 1 and 3) was carried out in 0.01M hydrochloric acid, 150 mL/cycle, at room temperature (2-minute immersions 4 times a day for 5 days). After all specimens were immersed in coffee for 14 days, new color measurements were performed. For total color change (∆E*), groups 1 (21.01) and 2 (23.10) presented lower values than groups 3 (27.76) and 4 (26.57). For luminosity (∆L*), the opposite occurred (groups: 1, -16.84; 2, -17.72; 3, -22.62; and 4, -21.22). For ∆a* and ∆b*, the only statistically significant difference was the group 1 ∆b* value, which was the lowest among all groups. The opacity remained stable in all groups. The results suggest that resin luminosity decreases and color variation increases when surface sealant is applied after erosive cycling and storage.

Color Stability of Microhybrid and Nanofilled Composite Resins: Effect of Surface Sealant Agents Containing Different Filler Content.

AIM: To evaluate the effect of surface sealants containing different filler content on the color stability of microhybrid and nanofilled composite resins. MATERIALS AND METHODS: The materials evaluated as study groups were comprised a nanofilled composite resin (Filtek Ultimate, 3M ESPE) and a microhybrid composite resin (Filtek Z250, 3M ESPE). Forty-five disc-shaped specimens (10 mm × 2 mm) were prepared from each composite resin. Each study group was divided into three subgroups: control, G-Coat Plus, and Fortify Plus (n = 15). The baseline color values (L*a*b*) of each specimen were measured using a spectrophotometer according to the CIE L*a*b* color scale. Then, the specimens were immersed in red wine for a period of 3 hours per day for 15 days (3 hours/day × 15 days). After the immersion period, the color values (L*a*b*) of each specimen were measured again. The ΔL*, Δa*, and Δb* values and the color change value (ΔE) were calculated. The data were statistically analyzed with two-way ANOVA and Duncan tests (p = 0.05). RESULTS: All the composite resin groups demonstrated/indicated much more color changes after immersion in red wine (ΔE > 3.3). The greater ΔE values were observed with the groups applied surface sealants than the control groups (p < 0.05). Fortify Plus further increased the ΔE values of both composite resins than G Coat Plus (p < 0.05). Filtek Ultimate showed higher ΔE values than Filtek Z250 in all the subgroups (p < 0.05). CONCLUSION: The surface sealants regardless of the filler content negatively influenced the color change of the composite resins after immersed in red wine. The microhybrid composite resin had better color stability than the nanofilled composite resin. CLINICAL SIGNIFICANCE: There is no favorable effect of using surface sealants on composite resins to prevent discoloration; besides, the sealants can also increase the color alteration.

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.

Anti-Candida activity and biocompatibility of silver nanoparticles associated with denture glaze: a new approach to the management of denture stomatitis.

The association of silver nanoparticles (AgNps) to sealant agent Palaseal® can be a promising alternative for complete denture wearers who may develop denture stomatitis (DS). The study aimed to evaluate the anti-Candida and biocompatible potential of silver nanoparticles synthesized by three routes associated with denture glaze to prevent and/or treat oral candidiasis. Surface acrylic resin specimens were treated with different associations of glaze with AgNps (VER+AgUV, VER+AgTurk and VER+AgGm). As controls, specimens were treated with glaze+nystatin (VER+Nyst), glaze only (VER) or submerged in PBS (PBS). Afterwards, Candida albicans biofilm was developed for 24 h, 15 d and 30 d. Subsequently, the biofilm was quantified by CFU/mL, XTT assay and confocal laser scanning microscopy. Fibroblasts were submitted to conditioned medium with the same associations for 24, 48 and 72 h and LIVE/DEAD® viability test was carried out. Regardless of the period, there was a significant reduction (p < 0.01) of viable fungal cells load, as well as inhibition of fungal metabolic activity, in specimens treated with glaze+AgNps associations, compared to VER and PBS. The anti-Candida effects of the associations were similar to the VER+Nyst group, with emphasis on VER+AgGm, which showed the highest percentage values of non-viable fungal cells maintained over time. The associations did not prove toxicity to fibroblasts. The AgNps exerted antimicrobial activity against C. albicans biofilms and are biocompatible. The most effective results were achieved with the association of glaze+silver nanoparticles synthesized by the green chemistry method (AgGm), proving to be an innovative alternative in the management of DS.

Evaluation of sealants to mitigate the release of per- and polyfluoroalkyl substances (PFAS) from AFFF-impacted concrete: Characterization and forecasting.

Per- and polyfluoroalkyl substances (PFAS) within concrete pads impacted by historical firefighting training using aqueous film-forming foam (AFFF) may be potential secondary sources of PFAS due to surficial leaching. This study aimed to (i) characterize the effectiveness of two commercially available sealants (Product A and Product B) in mitigating leaching of five PFAS (e.g., PFOS, PFOA, PFHxS, PFHxA, 6:2 FTS) from concrete surfaces at the laboratory-scale, and (ii) develop a model to forecast cumulative leaching of the same five PFAS over 20 years from sealed and unsealed concrete surfaces. Laboratory trials demonstrated that both sealants reduced the surficial leaching of the five PFAS studied, and Product B demonstrated a comparatively greater reduction in surface leaching than Product A as measured against unsealed controls. The cumulative PFOS leaching from an unsealed concrete surface is estimated by the model to be about 400 mg/m2 over 20 years and reached asymptotic conditions after 15 years. In contrast, the model output suggests asymptotic conditions were not achieved within the modeled time of 20 years after sealing with Product A and 85% of PFOS was predicted to have leached (∼340 mg/m2). Negligible leaching of PFOS after sealing with Product B was observed ( < 5 × 10-9 mg/m2). Results from modeled rainfall scenarios suggest PFAS leachability is reduced from sealed versus unsealed AFFF-impacted concrete surfaces.

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.

Prevention of white spot lesions around orthodontic brackets using organoselenium-containing antimicrobial enamel surface sealant.

OBJECTIVES: To investigate the antimicrobial potential of organo-selenium compound when applied as enamel surface sealant or primer (DenteShield™ [DS]) around orthodontic brackets to prevent enamel demineralization. METHODS: Human teeth were randomly assigned to seven treatment groups (15/group): control (No primer or sealant), Leopard light primer (LLP), DS Primer (DS-P), DS Enamel Surface Sealant (DS-S), Pro Seal, Opal Seal and combined DS-P/DS-S (DS-PS). Following etching, the tooth surface was coated with their respective material (except control group) and a bracket was bonded on each treated surface. All samples were subject to cariogenic challenge in a continuous flow microbial caries model at 37 °C in an incubator for 28 days. Demineralization was evaluated with Transerse microradiography to determine mineral loss (Δz) and lesion depth (LD). Data was statistically analyzed using Bonferroni protected Mann-Whitney tests (α = 0.05). RESULTS: Demineralization was obsessrved only in Control and LLP groups. Control group had significantly (p < 0.001) greater mean LD (109.47 ± 34.22 µm) and mean Δz (2251.07 ± 514.26 vol%µm) when compared with the LLP with mean LD (44.98 ± 11.69 µm) and Δz (700.67 ± 310.66 vol%µm). All other groups did not develop any lesions. CONCLUSIONS: Selenium-based primer and sealant used alone or in combination were effective in protecting enamel from demineralization around brackets. The combination of primer and enamel surface sealant has no added benefit. SIGNIFICANCE: DS-S and DS-P containing antimicrobial organo-selenium compound can prevent whitespot lesions development when applied on tooth surface during orthodontic treatment. Light primer applied alone on tooth surface may not provide adequate protection for the enamel around orthodontic appliances.

Effect of surface sealant on the surface roughness of different composites and evaluation of their microhardness.

PURPOSE: The aim of this study was to evaluate the effect of a surface sealant on the surface roughness of different composites and compare their microhardness values. MATERIALS AND METHODS: Sixty disc-shaped specimens were prepared and assigned to 6 groups (n =10). Groups were prepared as follows; Group 1 (Herculite XRV Ultra), Group 2 (Beautifil Bulk Restorative) and Group 3 (Filtek Bulk Fill Posterior Restorative). Groups 4, 5, and 6 were prepared by applying a surface sealant (BisCover LV) on the specimens in groups 1, 2 and 3. Surface hardness of the discs in group 1, 2, and 3 and surface roughness of the discs in all groups were measured using the Vickers hardness test and a profilometer, respectively. One-way ANOVA was used to test for differences among the groups. RESULTS: No significant differences were observed in the microhardness and roughness between the experimental and control groups for each restorative materials. Group 3 showed the highest surface hardness and group 4 showed the lowest surface roughness values. CONCLUSION: Using the BisCover LV resin after the polishing step has no significant effect on the surface roughness. The highest hardness values were obtained for the Filtek Bulk Fill Posterior Restorative after the polishing step. The smoothest surfaces were obtained for all experimental groups using the BisCover LV resin after the polishing step, Herculite XRV Ultra showed lower average roughness values than the other materials.

Prevention of erosions by a surface sealant and adhesives under abrasive conditions

It was the aim of the current in vitro study to test the erosion-preventive potential of an experimental surface sealant (K-0184) and currently marketed self-etch adhesive systems under abrasive conditions. Ninety-six dentine specimens were randomly allocated to eight groups (n=12): (1) positive control (no treatment), (2) K-0184, (3) Shield Force Plus, (4) Xeno Select, (5) Scotchbond Universal, (6) Adhese Universal, (7) OptiBond All-In-One, and (8) Clearfil SE Bond. Before and after sealing, dentine specimens were measured profilometrically to determine the layer thickness of the protective agents.During 12 days, the specimens were demineralized daily for 5 min using hydrochloric acid (pH=3) and abraded by applying 600 brushing strokes (F=2.5 N). Calcium content in the hydrochloric acid was determined using atomic absorption spectroscopy. Calcium concentration was consistently highest in the positive control group (p < 0.05 compared to all other groups). The lowest cumulated Ca release was measured for K-0184; it differed significantly (p < 0.05) from that determined in groups 4, 6, and 7. K-0184 also had the highest layer thickness (p < 0.05 compared to all other groups). It was concluded that the experimental surface sealant K-0184 and the adhesive systems Xeno Select, Scotchbond Universal, Adhese Universal, and Clearfil SE Bond prevent dentine erosion under the current abrasive conditions with a total of 7,200 brush strokes.

Influence of surface sealing on color stability and roughness of composite submitted to ultraviolet-accelerated aging.

AIM: In the present study, we evaluated the influence of surface sealing on color stability and surface roughness of a composite resin after accelerated artificial aging. METHODS: Thirty-two specimens of a composite were prepared. After 24 h, the specimens were polished and divided into four groups (n = 8), according to the surface sealant used, including the control, which had no sealant application. Baseline color was measured according to the CIELab system using a reflection spectrophotometer. Surface roughness was determined using a profilometer with a cut-off of 0.25 mm. After these tests, specimens were aged for 252 h in an ultraviolet (UV)-accelerated aging chamber. Color stability was determined by difference between coordinates obtained before and after the aging procedure. Data of color change and roughness were evaluated by anova and Fisher's exact test (α = 0.05). RESULTS: The results showed that the unsealed group had the highest color change compared to other groups (P = 0.0289), and there was no significant difference between groups sealed with surface sealant (P > 0.05). The artificial aging caused an increase in roughness values independent of the experimental group studied (P = 0.0015). CONCLUSION: The sealed composites showed lower color change after UV aging, but all groups showed clinically-acceptable color change, and only liquid polish decreased roughness.

The effect of surface sealants with different filler content on microleakage of Class V resin composite restorations.

OBJECTIVE: Microleakage is still one of the most cited reasons for failure of resin composite restorations. Alternative methods to prevent microleakage have been investigated increasingly. The aim of this study is to evaluate the microleakage in Class V resin composite restorations with or without application of surface sealants with different filler content. MATERIALS AND METHODS: Ninety-six cavities were prepared on the buccal and lingual surfaces with the coronal margins located in enamel and the cervical margins located in dentin. The cavities restored with an adhesive system (Clearfil SE Bond, Kuraray, Tokyo, Japan) and resin composite (Clearfil Majesty ES-2, Kuraray, Tokyo, Japan). Teeth were stored in distilled water for 24 h and separated into four groups according to the surface sealants (Control, Fortify, Fortify Plus, and G-Coat Plus). The teeth were thermocycled (500 cycles, 5-55° C), immersed in basic fuchsine, sectioned, and analyzed for dye penetration using stereomicroscope. The data were submitted to statistical analysis by Kruskal-Wallis and Bonferroni-Dunn test. RESULTS: The results of the study indicated that there was minimum leakage at the enamel margins of all groups. Bonferroni-Dunn tests revealed that Fortify and GC-Coat groups showed significantly less leakage than the Control group and the Fortify Plus group at dentin margins in lingual surfaces (P < 0.05). CONCLUSION: The all surface sealants used in this study eliminated microleakage at enamel margins. Moreover, unfilled or nanofilled surface sealants were the most effective in decreasing the degree of marginal microleakage at dentin margins. However, viscosity and penetrability of the sealants could be considered for sealing ability besides composition.

Effects of staining and bleaching on a nanohybrid composite with or without surface sealant.

OBJECTIVE: The effect of different staining solutions and a bleaching procedure on color stability and surface roughness of a nanohybrid resin composite were evaluated with or without liquid resin polishing (RP). MATERIALS AND METHODS: Ninety-six disc-shaped resin composite specimens (A1 Shade, Z550 Filtek 3M ESPE, St. Paul, MN, USA) were prepared and divided randomly into two groups (n = 48). Liquid RP (BisCover LV, Bisco Inc., Schaumburg, IL, USA) was applied in one group (RP) and not in the other (P). Specimen color and surface roughness were determined using a colorimeter and profilometer, respectively. After baseline measurements, each group was divided into four subgroups (n = 12) for immersion in a control (distilled water) or three different staining solutions (ice tea, red wine, and cola) for 1 week. Color and surface roughness were then reevaluated. After measurements, all specimens were bleached using a 35% hydrogen peroxide gel. The color and surface roughness of the specimens were reevaluated. STATISTICAL ANALYSIS: Data were subjected to an analysis of variance for repeated measurements among the groups (P < 0.05). RESULTS: Staining and bleaching did not change the surface roughness of the RP and P groups (P > 0.05). Discoloration in the red wine group was higher than for the other staining solutions for the RP (P < 0.001) and P groups (P = 0.018). CONCLUSION: Application of liquid RP did not enhance the color stability and surface roughness of the composite resin restoration.

Effect of surface sealing on stain resistance of a nano-hybrid resin composite.

PURPOSE: This study investigated the influence of sealant application on stain resistance of a nanohybrid resin composite compared to the efficacy of a bonding agent used as a surface sealant on prolonging color stability of the resin composite. MATERIALS AND METHODS: 28 disc-shaped materials were prepared from a nano-hybrid resin composite Filtek Z550 and assigned to four groups: G1K: nonsealed; G2:Adper Single Bond; G3: Fortify ; G4: Biscover LV. After 24 h storage in distilled water at 37˚C, all specimens were subjected to thermocycling and immersed into coffee solution. Color measurements were performed using spectrophotometer (VITA Easyshade; Vident) according to CIEL*a*b* system. RESULTS: Color change values were significantly different among the groups in each evaluation period except for after thermocycling (p<0.05). For 7 days evaluation period, the difference between G3 and G4 group was statistically significant while G4 exhibited statistically significant differences (p<0.05 and p<0.0001 respectively) compared to control (G1) in 14 day whereas no significant difference was found between GI and GII in 28-day evaluation period. However, ΔE values of sealed specimens (GIII, GIV) differed significantly from non-sealed (GI) specimens after 28 days of immersion in coffee solution (p<0.05 and p<0.0001 respectively). CONCLUSION: It may be concluded that using a bonding agent as a surface sealant does not increase stain resistance of resin composites of the sealants evaluated. Biscover LV showed the highest efficacy to prolong color stability of the resin composite.

The effect of bonding and surface sealant application on postoperative sensitivity from posterior composites.

PURPOSE: The purpose of the study was to evaluate the postoperative sensitivity of posterior Class I composite restoration at short-term, restorated with two different all-in-one self-etch adhesives with or without surface sealant application. MATERIALS AND METHODS: 44 restorations were inserted in 11 patients who required Class I restorations in their molars. Each patient received 4 restorations, thus four groups were formed; (1) G-Aenial Bond (GC, Japan); (2) Clearfil S3 Bond (Kuraray, Japan); (3) G-Aenial Bond+Fortify Plus (Bisco, USA), (4) Clearfil S3 Bond+Fortify Plus. Sensitivity was evaluated at 24h, 7, 15, and 30 days using cold air, ice, and pressure stimuli using a visual analog scale. Comparisons of continuous variables between the sensitivity evaluations were performed using the Friedman's One-Way Analysis of Variance with repeated measures test (p<0.05). RESULTS: The type of adhesive used and the application of a surface sealant had no significant effects in postoperative sensitivity (p>0.05). The use of Clearfil S3 Bond resulted in almost the same level of postoperative sensitivity as did the use of G-Aenial Bond. The highest sensitivity scores were observed for the surface sealant applied teeth without any statistical significance (p>0.05). CONCLUSION: Self etch adhesives displayed postoperative sensitivity. The sensitivity scores slightly decreased at the end of 30 days (p>0.05). Surface sealant application did not result in a decrease in sensitivity scores for either dentin adhesives.

Evaluation of a novel approach in the prevention of white spot lesions around orthodontic brackets.

BACKGROUND: The purpose of this study was to evaluate and compare the relative efficacy of a resin fissure sealant, nano-filled self-adhesive protective coating, resin infiltrant, glass ionomer cement (GIC), and GIC containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) in preventing the formation of subsurface lesions of enamel (SLE) adjacent to orthodontic brackets by acting as an enamel surface sealant (ESS). METHODS: Eighty-five enamel specimens with molar tubes bonded at their centre were randomly divided into five groups, each treated with a different material at the bracket's periphery. Specimens were stored in an acetate demineralization solution at pH 4.5 for 7 days at 37 °C then imaged using quantitative light-induced fluorescence (QLF) to determine the difference in fluorescence (∆F) between sound- and acid-exposed enamel. Lesion cross-sections were then examined using backscattered scanning electron microscopy (SEM) to measure lesion depth. RESULTS: The use of GIC alone or incorporating CPP-ACP significantly reduced ∆F compared with other materials. Backscattered SEM images showed no measurable demineralization for enamel treated with either GIC material in contrast with other groups, which showed statistically significant demineralization levels. CONCLUSIONS: The fluoride-releasing effects and CPP-ACP benefits of the GIC materials show promise as an effective ESS in inhibiting enamel demineralization adjacent to orthodontic brackets.

The effect of re-bonding using surface sealant or adhesive system on microleakage of class V resin composite restorations.

BACKGROUND: Microleakage is still one of the defects of resin composites that can lead to treatment failure; and re-bonding technique is one of the effective ways to reduce it. This study evaluated the effect of re-bonding with a surface sealant or a dentin adhesive on microleakage in class V microhybrid, nanohybrid, and packable composite restorations. MATERIALS AND METHODS: In this in vitro study, class V cavities with occlusal margins in enamel and cervical margins in dentin/cementum were prepared on the buccal and lingual surfaces of 54 extracted premolars. The prepared teeth were randomly assigned to three groups (3 group's Χ 18 teeth each), with each group being restored with microhybrid (Point 4); nanohybrid (Herculite XRV Ultra), and packable (Packable Premise) resin composite. Following finishing and polishing procedures, each group was randomly subdivided in to three subgroups (n = 12). The margins of two groups were both etched and re-bonded with surface sealant (Optiguard) or dentin adhesive (Opti Bond Solo Plus) and control group received no treatment. Specimens were thermocycled 1500 cycles, immersed in a methylene blue, sectioned, evaluated for microleakage using a stereomicroscope at a x 20 and scored on a scale of 0-3. Data were analyzed with Kruskal - Wallis, Mann - Whitney, and Wilcoxon tests (α = 0.05). RESULTS: There were no significant differences among the three resin composites tested, and also no significant differences among subgroups with the same surface treatment. Only the microhybrid and packable composite restorations sealed with Optiguard had significantly lower microleakage compared to the control subgroups at the occlusal margin. There were no significant differences between occlusal and cervical margins regarding the microleakage scores when compared to the control subgroups of microhybrid and packable composite restorations. CONCLUSION: The re-bonding technique could be considered as an advisable procedure in order to minimize microleakage and its effect might be material-dependent.