ascorbic-acid and Dental-Leakage

The aim of this study was to compare the neutralizing effect of antioxidant agents on the microleakage of dental restorations in nonvital teeth after bleaching with carbamide peroxide. Also assessed was the correlation of the microleakage data between an electrochemical and a staining technique.. Following root canal therapy, 40 sound and similar human maxillary central incisors were randomly divided into four groups of 10 specimens each (n=10). The groups were subjected to one of four treatments: Group 1, bleaching with 10 percent carbamide peroxide for periods of eight hours per day for one week without an antioxidant agent; Group 2, bleaching with 10 percent carbamide peroxide plus 10 percent sodium ascorbate gel; Group 3, bleaching with 10 percent carbamide peroxide plus 10 percent sodium ascorbate gel combined with a surfactant; and Group 4, no bleaching treatment (control group). In all groups, the access cavities were restored using the Single Bond Plus Adhesive system and Z100 resin-based composite. After 1,000 thermal cycles, the teeth were dried and three layers of nail varnish were applied over the entire surface area to within 1.0 mm of the restoration. A PVC-covered copper wire, with 3.0 mm of exposed bare wire, was inserted apically 5.0 mm into the canal, which was obturated with gutta-percha and sealed with sticky wax and varnish at the apex. Leakage was continuously monitored for 40 days using a conductimetric method. The teeth were immersed in 0.5 percent basic fuchsine for 24 hours, followed by sectioning for microscopic examination at 16x magnification. The data were analyzed using ANOVA and the Newman-Keuls multiple comparison, Kruskal-Wallis, Mann-Whitney, and Spearman's rho tests (p<0.05).. Based on the electrochemical results, cavities subjected to 10 percent sodium ascorbate gel combined with a surfactant displayed the least amount of microleakage while teeth that were bleached but not treated with an antioxidant exhibited significantly greater microleakage (p=0.007). These findings also were corroborated by the results of the staining experiments that showed a strong correlation between the electrochemical and staining findings (p=0.006) for the groups.. After nonvital bleaching and the application of the antioxidant 10 percent sodium ascorbate, the addition of the surfactant 0.2 percent Tween 80 to the conventional antioxidant formulation significantly reduced microleakage.. The addition of a surfactant to the antioxidant formulation significantly reduced microleakage when it was applied after bleaching.

Topics: Antioxidants; Ascorbic Acid; Bisphenol A-Glycidyl Methacrylate; Carbamide Peroxide; Coloring Agents; Composite Resins; Dental Leakage; Dental Materials; Dental Restoration, Permanent; Dentin-Bonding Agents; Electrochemical Techniques; Gels; Humans; Materials Testing; Peroxides; Polysorbates; Rosaniline Dyes; Silicon Dioxide; Surface-Active Agents; Temperature; Time Factors; Tooth Bleaching; Tooth Bleaching Agents; Tooth, Nonvital; Urea; Zirconium

To compare the effect of sodium hypochlorite (NaOCl), chlorhexidine, povidone iodine and sodium ascorbate on dye penetration associated with various dentine adhesives used within the pulp chamber.. One hundred and sixteen mandibular molar teeth were divided into eight groups of 12 teeth each by irrigation regimen and adhesive system. The roof of pulp chambers and roots were removed under water cooling. The pulp chambers in the experimental groups were irrigated with 5.25% NaOCl, 0.2% chlorhexidine, 5% w/v povidone iodine or 5.25% NaOCl followed by sodium ascorbate and restored with Surefil using either Prime & Bond NT or Xeno III with each irrigation regimen. Twenty teeth were used as control specimens in which no disinfectant was used before bonding. Ten teeth from each group were immersed in 2% methylene blue dye and assessed for dye penetration. The data were statistically analysed by Kruskal-Wallis and Mann-Whitney U-tests. Two samples in each group were observed under scanning electron microscopy for interfacial gap evaluation.. No significant difference was found in dye leakage between control and groups with 5.25% NaOCl pretreatment with both adhesive systems. Chlorhexidine and povidone iodine pretreatment resulted in significantly less dye penetration with Xeno III as compared with Prime & Bond NT. Sodium ascorbate treatment following NaOCl application significantly reduced microleakage and improved the marginal adaptation with both adhesive systems.. The type of irrigant affected the sealing ability of bonding agents inside the pulp chamber and was material specific. Xeno III had less dye penetration with CHX and povidone iodine whilst sodium ascorbate pretreatment after NaOCl reduced dye penetration with both PBNT and Xeno III.

Topics: Anti-Infective Agents, Local; Ascorbic Acid; Chlorhexidine; Coloring Agents; Composite Resins; Dental Bonding; Dental Leakage; Dental Marginal Adaptation; Dental Pulp Cavity; Dental Restoration, Permanent; Dentin-Bonding Agents; Humans; Materials Testing; Methylene Blue; Microscopy, Electron, Scanning; Polymethacrylic Acids; Povidone-Iodine; Root Canal Irrigants; Sodium Hypochlorite; Surface Properties

To (i) determine the effect of nonvital bleaching with 10% carbamide peroxide on the sealing ability of resin composite restorations bonded with a self-etching adhesive system; and (ii) compare the effects of antioxidant treatment and delayed restoration after bleaching on marginal seal.. Forty-eight noncarious maxillary incisors were divided into four groups (n=12) after conventional root canal treatment was completed. In group 1, access cavities were restored with a self-etching adhesive system and resin composite. In the remaining three groups, 10% carbamide peroxide bleaching gel was placed into the access cavities for periods of 8 h per day for 1 week. They were then restored in the same manner as group 1. Group 2 consisted of specimens restored immediately after bleaching. Group 3 specimens were treated with the antioxidant, 10% sodium ascorbate, whereas group 4 specimens were immersed in artificial saliva for 1 week before restoration. Ten specimens in each group were then subjected to dye leakage; the remaining 2 specimens were examined in a SEM (Jeol/JSM 5200, Tokyo, Japan). The dye penetration was assessed with the standard scoring system. Statistical analysis was carried out using the Kruskal-Wallis and the Mann-Whitney tests.. Groups 1, 3 and 4 exhibited similar leakage patterns and significantly less leakage than group 2 (P<0.0083). SEM examination of groups 1, 3 and 4 specimens demonstrated close adaptation of resin composite to cavity walls, whereas group 2 specimens did not.. Nonvital bleaching with 10% carbamide peroxide adversely affected the immediate sealing ability of resin composite restoration; both 10% sodium ascorbate treatment and a 1-week delay in restoration following bleaching improved the reduced sealing ability of resin composite.

Topics: Antioxidants; Ascorbic Acid; Carbamide Peroxide; Coloring Agents; Composite Resins; Dental Bonding; Dental Leakage; Dental Marginal Adaptation; Dental Restoration, Permanent; Dentin-Bonding Agents; Drug Combinations; Humans; Oxidants; Peroxides; Root Canal Therapy; Saliva, Artificial; Statistics, Nonparametric; Surface Properties; Time Factors; Tooth Bleaching; Urea

The available evidence of Er,Cr:YSGG lasers on bleached enamel is limited and controversial. It is assumed that Er,Cr:YSGG laser will be effective in reversing the effect of bleaching on adhesive bond integrity of enamel to resin composite.. The study aimed to evaluate the efficacy of Er,Cr:YSGG laser on bond strength and microleakage of bleached enamel.. From the 80 samples, 60 samples were bleached (40% hydrogen peroxide) and divided into three subgroups. Twenty bleached samples in each subgroup were exposed to 10% sodium ascorbate (Gp A), Er,Cr:YSGG laser (50 Hz and 4.5 W) (Gp L), and no treatment (Gp B), respectively. Twenty samples were not bleached (Control-C). Using etch and rinse technique, resin composite was built-up on enamel and photopolymerized. Ten specimens in each group were tested for shear bond strength at a crosshead speed of 1 mm/min. Ten specimens in each group were tested for microleakage using 2% methylene blue. Data were analyzed using analysis of variance (ANOVA) and Tukey post hoc multiple comparisons test.. The mean bond strength of specimens in group L (30.83 ± 1.7000) was comparable with group A (31.38 ± 2.03) and was significantly higher than bleached specimens (9.49 ± 0.86) (p < 0.001). The highest mean microleakage values were observed in bleached group (630.32 ± 156.58). The mean microleakage among control (36.66 ± 27.33) and laser group specimens (55.32 ± 34.98) was comparable (p > 0.05).. Treatment of bleached enamel with erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser showed a significant reversal effect on the enamel bond strength and microleakage scores.. Er,Cr:YSGG laser (50 Hz, 4.5 W) treatment has the potential to restore the bond strength of bleached enamel to resin composite.

Topics: Ascorbic Acid; Composite Resins; Dental Bonding; Dental Enamel; Dental Etching; Dental Leakage; Dental Stress Analysis; Humans; Hydrogen Peroxide; Lasers, Solid-State; Shear Strength; Tooth Bleaching Agents

This study assessed the effect of antioxidants vitamin C (Vit. C), vitamin E (Vit. E) and quercetin (Querc) on the dentin bonding performance, degree of conversion, and rate of polymerization of three commercial adhesive systems (Adper Single Bond 2 [SB], Clearfil SE Bond [CSE], Adper Easy Bond [EB]).. Human premolars were restored using antioxidant-doped adhesives. The samples were stored for 24 h in distilled water or 6 months under simulated pulpal pressure. Teeth were cut into sticks and the microtensile bond strength (μTBS) to dentin was tested in a universal testing machine. Qualitative nanoleakage analysis was performed from a central stick of each restored tooth. Degree of conversion and rate of polymerization of adhesive systems were evaluated in triplicate using real-time FT-IR.. Although the inclusion of the antioxidants negatively affected the μTBS over 24 h, the antioxidant-doped adhesives maintained (SB-Vit. C, SB-Vit. E, CSE-Vit. C, EB-Querc) or increased (SB-Querc, CSE-Vit. E, CSE-Querc, EB-Vit. E, and EB-Vit. C) their μTBS during 6 months of storage. Only the μTBS of Adper Single Bond 2 dropped significantly after 6 months among the control groups. Slight changes in the nanoleakage pattern after aging were observed in all groups, except for the EB-control group, which showed a noteworthy increase in nanoleakage after 6 months, and for EB-Vit. C, which presented a remarkable decrease. A lower degree of conversion was obtained with all antioxidants in SB and EB, except for the EB-Vit. E group. Similar degrees of conversion were attained in control and experimental groups for CSE. The rate of polymerization was reduced in antioxidant-doped adhesives.. The performance of antioxidants changed according to the adhesive system to which they were added, and antioxidant-doped adhesives appear to have a positive effect on the adhesive interface durability, since their bond strength obtained after 24 h was maintained or increased over time.

Topics: Antioxidants; Ascorbic Acid; Composite Resins; Dental Bonding; Dental Cements; Dental Leakage; Dental Stress Analysis; Dentin; Dentin-Bonding Agents; Humans; Hydrolysis; Materials Testing; Microscopy, Electron, Scanning; Polymerization; Quercetin; Resin Cements; Spectroscopy, Fourier Transform Infrared; Stress, Mechanical; Tensile Strength; Time Factors; Vitamin E; Water

This in vitro study assessed the adhesion of Epiphany self-etch (SE) root canal sealer to dentin treated with different irrigation regimens.. Flat dentin surfaces were obtained from human third molar teeth; smear layer was created on each sample. Five groups of 10 samples each were conditioned with one of the following regimens: (1) deionized water for 10 minutes; (2) 5% sodium hypochlorite (NaOCl) for 10 minutes; (3) 5% NaOCl for 10 minutes and then 10% sodium ascorbate (Na-Ascr) for 10 minutes; (4) 5% NaOCl for 10 minutes and then 2% chlorhexidine (CHX) for 5 minutes; or (5) 5% NaOCl for 10 minutes and then 10% Na-Ascr for 10 minutes, followed by 2% CHX for 5 minutes. The conditioned dentin surfaces were dried with absorbent paper points. The Epiphany SE sealer was placed on each dentin surface with the use of hollow stainless steel tubes with specific diameter and height. The samples were stored in 100% humidity at 37°C for 7 days and then tested for shear bond strength in a universal testing machine.. Shear bond strength data were analyzed by one-way analysis of variance and Tukey post hoc tests (P < .05). There were statistically significant differences among the groups.. NaOCl decreased the bond strength of Epiphany SE sealer to dentin, whereas the use of Na-Ascr reversed this negative effect of NaOCl. CHX had neither negative nor positive influence on the bond strength.

Topics: Analysis of Variance; Ascorbic Acid; Chlorhexidine; Dental Bonding; Dental Leakage; Dental Marginal Adaptation; Dentin; Drug Interactions; Drug Therapy, Combination; Humans; Molar; Root Canal Filling Materials; Root Canal Irrigants; Shear Strength; Sodium Hypochlorite; Statistics, Nonparametric

To reduce the microleakage of a self-etching priming dentin adhesive with the use of antioxidant or bur finishing after sodium-hypochlorite or hydrogen-peroxide irrigation.. 70 single-root canals were enlarged and seven different treatment protocols were applied throughout the root canal treatment: The roots in Groups 1, 2, and 3 were irrigated with sodium-hypochlorite. Group 1 was used as the negative control with only sodium-hypochlorite irrigation whereas in Group 2, sodium-ascorbate was applied as an additional irrigation agent following sodium-hypochlorite. Irrigation procedure in Group 3 was same as in Group 1, however, after the roots in this group were obturated, cavities were cleaned off with a carbide bur (bur-finishing) to remove the effect of sodium-hypochlorite. Hydrogen-peroxide irrigation was used in Groups 4, 5 and 6; the procedural steps were similar to those of Groups 1, 2 and 3: hydrogen-peroxide in Group 4, sodium-ascorbate application in Group 5, and bur-finishing in Group 6. Group 7 was the positive control with saline irrigation alone. All roots were obturated with Diaket sealer and gutta-percha cones using cold lateral condensation technique immediately after irrigation. A self-etching priming adhesive plus resin composite was applied after the endodontic treatment. The microleakage of dentin margins was determined using dye-penetration technique with clearing process.. The Kruskal-Wallis followed by Mann-Whitney test showed that both sodium-hypochlorite and hydrogen-peroxide deteriorated the marginal seal of the dentin adhesive (P < 0.05), however, following both irrigation solutions the use of sodium-ascorbate reduced the microleakage (P < 0.05). Additionally, when sodium-ascorbate or bur-finishing was applied to remove the deterioration caused by sodium-hypochlorite or hydrogen-peroxide, the microleakage scores obtained were not different from that of the positive control (P > 0.05).

Topics: Antioxidants; Ascorbic Acid; Dental Leakage; Dentin; Dentin-Bonding Agents; Humans; Hydrogen Peroxide; Incisor; Root Canal Irrigants; Root Canal Obturation; Sodium Hypochlorite; Statistics, Nonparametric

Oxygen inhibits polymerization of resin-based materials. We hypothesized that compromised bonding to bleached enamel can be reversed with sodium ascorbate, an anti-oxidant. Sandblasted human enamel specimens were treated with distilled water (control) and 10% carbamide peroxide gel with or without further treatment with 10% sodium ascorbate. They were bonded with Single Bond (3M-ESPE) or Prime&Bond NT (Dentsply DeTrey) and restored with a composite. Specimens were prepared for microtensile bond testing and transmission electron microscopy after immersion in ammoniacal silver nitrate for nanoleakage evaluation. Bond strengths of both adhesives were reduced after bleaching but were reversed following sodium ascorbate treatment (P < 0.001). Resin-enamel interfaces in bleached enamel exhibited more extensive nanoleakage in the form of isolated silver grains and bubble-like silver deposits. Reduction of resin-enamel bond strength in bleached etched enamel is likely to be caused by a delayed release of oxygen that affects the polymerization of resin components.

Topics: Acid Etching, Dental; Analysis of Variance; Antioxidants; Ascorbic Acid; Bisphenol A-Glycidyl Methacrylate; Carbamide Peroxide; Composite Resins; Dental Bonding; Dental Enamel; Dental Leakage; Dentin-Bonding Agents; Drug Combinations; Humans; Microscopy, Electron; Oxidants; Oxidation-Reduction; Peroxides; Polymers; Polymethacrylic Acids; Silver; Silver Staining; Statistics as Topic; Surface Properties; Tensile Strength; Tooth Bleaching; Urea

The mechanism responsible for sodium-hypochlorite-induced reduction in dentin bond strength and its reversal with reducing agents is unknown. This study examined the relationship between nanoleakage and reversal of compromised bonding to oxidized dentin. Acid-etched dentin was completely depleted of demineralized collagen matrix when sodium hypochlorite was used. Specimens were bonded with two single-bottle dentin adhesives. They were immersed in ammoniacal silver nitrate for 24 hrs before being processed for transmission electron microscopy. For both adhesives, tensile bond strengths of acid-etched dentin were significantly reduced after sodium hypochlorite treatment, but were reversed when sodium ascorbate was used. After sodium hypochlorite application, reticular nanoleakge patterns in hybrid layers were replaced by vertical, shag-carpet-like patterns along the demineralization front. This type of nanoleakage was completely eliminated after sodium ascorbate treatment with the materials tested. Residual sodium hypochlorite within the porosities of mineralized dentin may result in incomplete resin polymerization, and hence compromised bond strength.

Topics: Acid Etching, Dental; Ascorbic Acid; Collagen; Dental Bonding; Dental Leakage; Dentin; Dentin-Bonding Agents; Humans; Methacrylates; Microscopy, Electron; Oxidants; Polymers; Reducing Agents; Silver Staining; Sodium Hypochlorite; Stress, Mechanical; Tensile Strength