Enhanced tooth bleaching with a hydrogen peroxide/titanium dioxide gel

BACKGROUND

This study aimed to explore the effects of the titanium dioxide (TiO2) concentration and particle size in hydrogen peroxide (HP) on tooth bleaching effectiveness and enamel surface properties.

METHODS

TiO2 at different concentrations and particle sizes was incorporated into 40% HP gel to form an HP/TiO2 gel. The specimens were randomly divided into 8 groups: C1P20: HP + 1% TiO2 (20 nm); C3P20: HP + 3% TiO2 (20 nm); C5P20: HP + 5% TiO2 (20 nm); C1P100: HP + 1% TiO2 (100 nm); C3P100: HP + 3% TiO2 (100 nm); C5P100: HP + 5% TiO2 (100 nm); C0: HP with LED; and C0-woL: HP without LED. Bleaching was conducted over 2 sessions, each lasting 40 min with a 7-day interval. The color differences (ΔE00), whiteness index for dentistry (WID), surface microhardness, roughness, microstructure, and composition were assessed.

RESULTS

The concentration and particle size of TiO2 significantly affected ΔE00 and ΔWID values, with the C1P100 group showing the greatest ΔE00 values and C1P100, C3P100, and C5P100 groups showing the greatest ΔWID values (p < 0.05). No significant changes were observed in surface microhardness, roughness, microstructure or composition (p > 0.05).

CONCLUSIONS

Incorporating 1% TiO2 with a particle size of 100 nm into HP constitutes an effective bleaching strategy to achieve desirable outcomes.

Evaluating Polishability of Zirconia Impregnated PMMA Nanocomposite for Denture Base Application

Artificial biomaterials are being developed for use in denture base with symmetrical properties to restore the aesthetics and functionalities. The rough surface of denture base resin promotes the adhesion of microorganisms and plaque accumulation. This study aimed to explore the consequences of polishing times on the surface roughness of high-impact (HI) heat-polymerized PMMA denture base acrylic resin reinforced with zirconia nanoparticles (nanocomposite). Thirty specimens (25 ± 0.50 mm in diameter and 2 ± 0.10 mm thickness) were fabricated from HI PMMA by adding zirconia nanoparticles at different concentrations of (0 wt.%, 1.5 wt.%, 3 wt.%, 5 wt.%, 7 wt.%, and 10 wt.%). Specimens were divided into six groups (n = 5) and surface roughness (Ra) was measured before and after polishing with a standard protocol for one and two minutes. The addition of zirconia in PMMA at low concentrations (1.5 wt.%, 3 wt.%, and 5 wt.%) did not negatively affect the surface finish of the denture base composites following conventional polishing and remained below the clinically acceptable limit (0.2 µm). After one minute of polishing, only the 10 wt.% zirconia (0.17 ± 0.03 µm) demonstrated a substantial rise in median surface roughness, in comparison with the control group (0.11 ± 0.01 µm). It is concluded that the group containing 3 wt.% (0.10 ± 0.01 µm) of zirconia is the optimum concentration to obtain the best symmetrical surface finish after two minutes of polishing.

Effectiveness of denture microwave disinfection for treatment of denture stomatitis: A systematic review and meta-analysis

OBJECTIVE

The aim of this systematic review was to evaluate the effectiveness of removable complete denture disinfection using microwaves for the treatment of denture stomatitis.

METHODS

This review identified studies comparing the efficacy of microwave prosthesis disinfection (I) to topical antifungal therapy (C) in the treatment of denture stomatitis (O), which included only individuals who used complete dentures and presented with denture stomatitis (P). The search was performed in six databases and identified 1524 records; after the removal of duplicates, 816 articles remained. Three articles were selected for qualitative synthesis and two for meta-analysis. Random-effects meta-analysis estimated the polled effects of microwave disinfection and antifungal therapy on the Candida counts and clinical manifestation of denture stomatitis. The GRADE approach was used to estimate the certainty of evidence.

RESULTS

All included studies reported significant reductions in Candida counts and the frequency of denture stomatitis of groups subjected to microwave disinfection of dentures and topical antifungal therapy with nystatin. Significative differences between treatments were only detected for Candida quantification in the palate, within 90 days follow-up period (SMD = 0.47, 95% CI = 0.02-0.91). Meta-analyses did not show any further differences between treatments (p > .05), considering the Candida quantification in dentures and the frequency of clinical signs of denture stomatitis. The certainty of the evidence was considered as low, according to GRADE approach.

CONCLUSION

Microwave disinfection of complete dentures can be considered as efficient as antifungal therapy for the treatment of denture stomatitis. However, further well-designed studies are necessary to confirm such evidence.

Evaluation of methods for stain removal in acrylic resin denture teeth: in vitro study

Abstract Introduction The staining of artificial teeth can be related to the acrylic resin abrasion caused by brushing, resulting in higher deposition of dyes from the beverage, and consequently higher aesthetic damage. Objective The aim of this in vitro study was to evaluate methods for removal of stains from acrylic denture teeth using spectrophotometric analysis. Material and method Artificial teeth were divided into twelve groups (n=10) according to the type of treatment (re-polishing - Re or immersion in Corega Tabs - Sp), staining solutions, coffee (Cf) and Coca-Cola® (Cc) or water (W) and with/without toothbrushing (B). The Sp specimens were submitted to seven immersion cycles (5 min each). The Re specimens were polished with pumice stone followed by Spain white paste. Color differences (ΔE) were captured by a spectrophotometer: T0 (baseline), T1 (after brushing/immersion in solutions) and T2 (after Re or Sp). Result Statistically significant color change between T1 and T2 (paired T-test; α =.05) was observed for the group CfSp (p=.032); and for the groups BWRe (p=.000), BCfRe (p=.049) and CcRe (p=.042). Higher color changes were observed for the specimens submitted to toothbrushing (ANOVA two way; p<.001). Conclusion It could be concluded that the immersion in sodium perborate (Corega Tabs) can be used for removal of coffee stains from denture teeth, and re-polishing for removal of Coca-Cola® stains. Still, toothbrushing produced greater color changes on denture teeth, regardless of the immersion solution.

Effect of Disinfection on the Bond Strength between Denture Teeth and Microwave-Cured Acrylic Resin Denture Base

PURPOSE

Denture tooth debonding is a common complication for denture wearers; however, the effect of complete denture disinfection on bonding between denture teeth and acrylic resin remains unclear. The aim of this study was to evaluate the effect of disinfection methods on the bond strength between denture teeth and microwave-cured acrylic resin denture base.

MATERIALS AND METHODS

Three commercial brands of denture teeth (Trilux, Biolux, Vipi Dent Plus) and one microwave-cured acrylic resin denture base were tested. Each brand of denture teeth was divided into seven groups (n = 6; estimated by partial Eta squared). The specimenss of groups H and Cl were immersed in 1% sodium hypochlorite and 4% chlorhexidine digluconate for 7 days, respectively. In group Br, the specimens were subjected to toothbrush simulation under 200 g of force for 20,000 cycles. In groups Br-H and Br-Cl, the specimens were brushed and further disinfected with 1% sodium hypochlorite and 4% chlorhexidine digluconate, respectively. In control groups 1 (Co1) and 2 (Co2), the specimens were stored in distilled water for 50 ± 2 hours and 7 days, respectively. Shear bond strength testing was performed at the resin/tooth interface in a universal testing machine at a 1 mm/min crosshead speed. The failure pattern was quantified and classified into adhesive, cohesive, or mixed. Data were analyzed using two-way ANOVA and Tukey HSD test (α = 0.05).

RESULTS

Disinfection with 1% sodium hypochlorite (p = 0.031), brushing (p < 0.0001), and association of brushing with either 1% sodium hypochlorite (p < 0.0001) or 4% chlorhexidine digluconate (p = 0.01) reduced the bond strength between denture teeth and microwave-cured acrylic resin denture base. All commercial brands of denture teeth presented a similar bond strength (p > 0.05). The failure pattern was predominantly adhesive independent of the disinfection method and denture tooth brand.

CONCLUSIONS

Disinfection with sodium hypochlorite, brushing, and the association of mechanical and chemical methods reduced the bond strength between denture tooth and microwave-cured acrylic resin denture base.

In vitro treatment of Candida albicans biofilms on denture base material with volume dielectric barrier discharge plasma (VDBD) compared with common chemical antiseptics

OBJECTIVES

To prevent oral candidiasis, it is crucial to inactivate Candida-based biofilms on dentures. Common denture cleansing solutions cannot sufficiently inactivate Candida albicans. Therefore, we investigated the anticandidal efficacy of a physical plasma against C. albicans biofilms in vitro.

MATERIALS AND METHODS

Argon or argon plasma with 1 % oxygen admixture was applied on C. albicans biofilms grown for 2, 7, or 16 days on polymethylmethacrylate discs; 0.1 % chlorhexidine digluconate (CHX) and 0.6 % sodium hypochlorite (NaOCl) solutions served as positive treatment controls. In addition, these two solutions were applied in combination with plasma for 30 min to assess potential synergistic effects. The anticandidal efficacy was determined by the number of colony forming units (CFU) in log(10) and expressed as reduction factor (RF, the difference between control and treated specimen).

RESULTS

On 2-day-biofilms, plasma treatment alone or combined with 30 min CHX treatment led to significant differences of means of CFU (RF = 4.2 and RF = 4.3), clearly superior to CHX treatment alone (RF = 0.6). Plasma treatment of 7-day-or 16-day-old biofilms revealed no significant CFU reduction. The treatment of 7-day-old (RF = 1.7) and 16-day-old (RF = 1.3) biofilms was slightly more effective with NaOCl alone than with the combined treatment of NaOCl and plasma (RF = 1.6/RF = 1.9). The combination of CHX and plasma increased the RF immaterially.

CONCLUSION

The use of plasma alone and in combination with antiseptics is promising anticandidal regimens for daily use on dentures when biofilms are not older than 2 days.

CLINICAL RELEVANCE

Plasma could help to reduce denture-associated candidiasis.

Comparison of denture microwave disinfection and conventional antifungal therapy in the treatment of denture stomatitis: a randomized clinical study

OBJECTIVE

The aim of this study was to compare the effectiveness of denture microwave disinfection and antifungal therapy on treatment of denture stomatitis.

STUDY DESIGN

Sixty denture wearers with denture stomatitis (3 groups; n = 20 each), were treated with nystatin or denture microwave disinfection (1 or 3 times/wk) for 14 days. Mycologic samples from palates and dentures were quantified and identified with the use of Chromagar, and clinical photographs of palates were taken. Microbiologic and clinical data were analyzed with the use of a series of statistical tests (α = .05).

RESULTS

Both treatments similarly reduced clinical signs of denture stomatitis and growth on palates and dentures at days 14 and 30 (P > .05). At sequential appointments, the predominant species (P < .01) isolated was C. albicans (range 98%-53%), followed by C. glabrata (range 22%-12%) and C. tropicalis (range 25%-7%).

CONCLUSIONS

Microwave disinfection, at once per week for 2 treatments, was as effective as topical antifungal therapy for treating denture stomatitis.