Effects of the Concentration and Composition of In-office Bleaching Gels on Hydrogen Peroxide Penetration into the Pulp Chamber

2015 ◽  
Vol 40 (2) ◽  
pp. E76-E82 ◽  
Author(s):  
AP Mena-Serrano ◽  
SO Parreiras ◽  
EMS do Nascimento ◽  
CPF Borges ◽  
SB Berger ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Acetate Buffer ◽  
Acetate Buffer Solution ◽  
Control Group ◽  
Pulp Chamber ◽  
Pulp Tissue ◽  
Buffer Solution ◽  
Bleaching Procedure ◽  
Blue Solution

SUMMARY In tooth whitening, the hydrogen peroxide (HP) diffuses in the enamel and dentin, reaching the pulp. This in vitro study aimed to quantify the penetration of HP in the pulp chamber in teeth submitted to bleaching agents of different concentrations of HP without calcium (HP 20% [20CF], HP 35% [35CF]) and with calcium (HP 20% [20CC], HP 35% [35CC]). Method Fifty human premolars were sectioned 3 mm from the cemento-enamel junction and the pulp tissue was removed. The teeth were divided into five groups according to treatment and with a control group (n=10). An acetate buffer solution was placed in the pulp chamber of all teeth. The control group was exposed only to distilled water, while the other groups were treated with a bleaching procedure, according to the manufacturer's recommendations. After treatment, the acetate buffer solution was transferred to a glass tube in which leuco-crystal violet and peroxidase solutions were added, resulting in a blue solution. The optical density of this blue solution was determined spectrophotometrically and converted into micrograms equivalent to the HP. Data were analyzed using analysis of variance and Tukey tests (α=0.05). Results The HP concentration did not affect the HP inside the pulp chamber, but the presence of calcium significantly reduced it (p<0.0001). Conclusion The amount of HP that reaches the pulp chamber depends on the bleaching protocol and the product employed, and it seems to be less affected by HP concentration.

Quantification of Peroxide Ion Passage in Dentin, Enamel, and Cementum After Internal Bleaching With Hydrogen Peroxide

2012 ◽  
Vol 37 (6) ◽  
pp. 660-664 ◽  
Author(s):  
RM Palo ◽  
I Bonetti-Filho ◽  
MC Valera ◽  
CHR Camargo ◽  
SEA Camargo ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
External Surface ◽  
Acetate Buffer Solution ◽  
Bleaching Agent ◽  
Pulp Chamber ◽  
Control Groups ◽  
Buffer Solution ◽  
Exposed Area ◽  
Blue Solution ◽  
Nail Varnish

SUMMARY The aim of this study was to evaluate the amount of peroxide passage from the pulp chamber to the external enamel surface during the internal bleaching technique. Fifty bovine teeth were sectioned transversally 5 mm below the cemento-enamel junction (CEJ), and the remaining part of the root was sealed with a 2-mm layer of glass ionomer cement. The external surface of the samples was coated with nail varnish, with the exception of standardized circular areas (6-mm diameter) located on the enamel, exposed dentin, or cementum surface of the tooth. The teeth were divided into three experimental groups according to exposed areas close to the CEJ and into two control groups (n=10/group), as follows: GE, enamel exposure area; GC, cementum exposed area; GD, dentin exposed area; Negative control, no presence of internal bleaching agent and uncoated surface; and Positive control, pulp chamber filled with bleaching agent and external surface totally coated with nail varnish. The pulp chamber was filled with 35% hydrogen peroxide (Opalescence Endo, Ultradent). Each sample was placed inside of individual flasks with 1000 μL of acetate buffer solution, 2 M (pH 4.5). After seven days, the buffer solution was transferred to a glass tube, in which 100 μL of leuco-crystal violet and 50 μL of horseradish peroxidase were added, producing a blue solution. The optical density of the blue solution was determined by spectrophotometer and converted into microgram equivalents of hydrogen peroxide. Data were submitted to Kruskal-Wallis and Dunn-Bonferroni tests (α=0.05). All experimental groups presented passage of peroxide to the external surface that was statistically different from that observed in the control groups. It was verified that the passage of peroxide was higher in GD than in GE (p<0.01). The GC group presented a significantly lower peroxide passage than did GD and GE (p<0.01). It can be concluded that the hydrogen peroxide placed into the pulp chamber passed through the dental hard tissues, reaching the external surface and the periodontal tissue. The cementum surface was less permeable than were the dentin and enamel surfaces.

Effect of Adhesive Restoration and Bleaching Technique on the Concentration of Hydrogen Peroxide In the Pulp Chamber

2017 ◽  
Vol 42 (2) ◽  
pp. E44-E54 ◽  
Author(s):  
V Cavalli ◽  
BG Silva ◽  
SB Berger ◽  
G Abuna ◽  
FC Marson ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Confocal Microscopy ◽  
Light Emitting Diode ◽  
Acetate Buffer Solution ◽  
Control Group ◽  
Light Activation ◽  
Pulp Chamber ◽  
Buffer Solution ◽  
Light Emitting ◽  
Halogen Light

SUMMARY This study aimed to quantify the concentration of hydrogen peroxide into the pulp chamber in the presence or absence of adhesive enamel restorations and to analyze the resin-dentin interface of bleached groups. Bovine incisors (120) were randomly divided into three groups according to enamel treatment (n=40 each): (1) enamel without restoration (control); (2) enamel cavities (3 mm diameter × 1.5 mm depth) restored with a silorane-based (SB) system; or (3) enamel cavities (3 mm diameter × 1.5 mm depth) restored with a dimethacrylate-based (DB) system. Restorations were thermocycled, and all groups were submitted to one application of 35% hydrogen peroxide (HP) agent for 45 minutes and subjected to four light activation methods (n=10 each): without light, light-emitting diode (LED), LED/diode laser, or halogen light. Acetate buffer solution was placed into the pulp chamber before bleaching, and this solution was collected to spectrophotometrically determine the concentration of HP that reached the pulp chamber after bleaching. Rhodamine B was added to the HP agent and applied on additional enamel samples of each group for 24 hours. Samples were sectioned mesiodistally, and the bleaching agent was traced using confocal microscopy. According to two-way analysis of variance and Tukey test (α=0.05), the HP concentration in the pulp chamber of the control group was significantly lower than that of the SB group (p<0.05), regardless of light activation. No differences were observed between DB and SB groups and between control and DB groups, except for the DB halogen light activated group, which exhibited higher HP intrapulpal concentration (p<0.05). Confocal microscopy exhibited HP diffusion through the interface of the SB and DB restored groups as well as enamel prisms in the control group. The SB restorative system increased the HP diffusion into the pulp chamber, but HP was able to diffuse even in the absence of enamel restorations.

Effects of pH and Application Technique of In-office Bleaching Gels on Hydrogen Peroxide Penetration into the Pulp Chamber

2019 ◽  
Vol 44 (6) ◽  
pp. 659-667 ◽  
Author(s):  
L Balladares ◽  
LF Alegría-Acevedo ◽  
A Montenegro-Arana ◽  
LA Arana-Gordillo ◽  
C Pulido ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Color Change ◽  
Acidic Ph ◽  
Alkaline Ph ◽  
Pulp Chamber ◽  
Pulp Tissue ◽  
Application Technique ◽  
Significant Difference ◽  
Bleaching Gels

SUMMARY Objective: This in vitro study aimed to quantify the penetration of hydrogen peroxide (HP) into the pulp chamber in teeth submitted to in-office bleaching with varied pH and application techniques. The color change and pH of the in-office bleaching product during application was also evaluated. Methods and Materials: Ninety-six human premolars were used and randomly divided into 10 groups (n=9) according to the following combination of factors: pH of in-office bleaching agents (two neutral/alkaline pH: Opalescence Boost 38% and Whiteness HP Blue 35% and three acidic pH: Whiteness HP Maxx 35%, Lase Peroxide Sensy 35%, and Total Blanc Office 35%) and application modes (for 3 × 15 minutes [3×15] and 1 × 45 minutes [1×45]). An additional group of non-bleached teeth (control; n=6) was added. First, all teeth were sectioned 3 mm from the cementoenamel junction and the pulp tissue was removed. An acetate buffer was placed in the pulp chamber of all teeth. After bleaching, this solution was transferred to a glass tube in which HP was allowed to react with other components, resulting in a pink solution. The optical density of this pink solution was measured using ultraviolet-visible spectroscopy and converted into amount of HP. Color change before and 1 week after bleaching was evaluated using a digital spectrophotometer. A pH meter with a 6-mm circular and flat surface was used in contact with the enamel surface to quantify the pH of the bleaching gels during application. Data were analyzed using two-way analysis of variance and Tukey tests (α=0.05). Results: Overall, lower mean HP penetration values were observed for Opalescence Boost 38% and Whiteness HP Blue 35% compared with other bleaching gels (p<0.05). Opalescence Boost 38% and Whiteness HP Blue 35% were not influenced by the application technique (p>0.05). However, lower mean HP penetration values were observed for Whiteness HP Maxx 35%, Total Blanc Office 35%, and Lase Peroxide Sensy 35% when using the 3×15 application technique compared with the 1×45 technique (p<0.05). Significant whitening was detected and no significant difference of color change was observed between groups (p>0.54). The pH did not change during the 3×15 application technique; however, all acidic bleaching gels significantly decreased in pH when applied for 1×45 (p<0.01). Conclusions: The amount of HP that reaches the pulp chamber was lower when neutral/alkaline pH gels were used, independently of the application technique. When considering acidic pH gels, it is preferable to use the 3×15 application technique, mainly because longer application time (1×45) results in lower pH. No difference was observed between groups with regards to color change.

scholarly journals Initial and pulp chamber concentration of hydrogen peroxide using different bleaching products

2020 ◽  
Vol 23 (2) ◽  
Author(s):  
Sibelli Olivieri Parreiras ◽  
Michael Willian Favoreto ◽  
Gustavo Pereira Cruz ◽  
Anderson Gomes ◽  
Christiane Philippini Ferreira Borges ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Dental Enamel ◽  
Pairwise Comparison ◽  
Spectrophotometric Analysis ◽  
Tooth Bleaching ◽  
Acetate Buffer Solution ◽  
Pulp Chamber ◽  
Carbamide Peroxide ◽  
Buffer Solution ◽  
Significant Difference

Objective: This study’s aim was to quantify the hydrogen peroxide (HP) penetration into the pulp chamber of teeth submitted to different protocols of bleaching. Material and Methods: Ninety premolars were randomly divided into nine groups according to the bleaching agent protocol (n = 10): control (no bleaching), carbamide peroxide 10% [10% CP], carbamide peroxide 16% [16% CP], carbamide peroxide 22% [22% CP], hydrogen peroxide 4% [4% HP], hydrogen peroxide 6% [6% HP], hydrogen peroxide 7.5% [7.5% HP], hydrogen peroxide 10% [10% HP] and hydrogen peroxide 35% [35% HP]. The penetration of HP was measured via spectrophotometric analysis of the acetate buffer solution from the pulp chamber. The absorbance of the resulting solution was determined in a spectrophotometer and converted into equivalent concentration of HP (μg/ mL). To analyze the concentration of HP, the titration of bleaching agents with potassium permanganate was used. Data were subjected to ANOVA and Tukey’s test for pairwise comparison (α = 0.05). Results: Higher concentration of HP in the pulp chamber was found in the HP 35% group (p < 0.0001). No significant difference between at-home protocols were observed (p = 0.64). Titration values showed that the concentration of the products was similar to that claimed by the manufacturer. Conclusion: It follows that the amount of HP that reaches the pulp chamber is not proportional to the concentration of whitening gels, but depends on the application time recommended by the manufacturers.KEYWORDSAt-home bleaching; Dental enamel permeability; Inoffice bleaching; Tooth bleaching. 

scholarly journals Transenamel and Transdentinal Penetration of Hydrogen Peroxide Applied to Cracked or Microabrasioned Enamel

2014 ◽  
Vol 39 (2) ◽  
pp. 166-173 ◽  
Author(s):  
ALF Briso ◽  
APB Lima ◽  
RS Gonçalves ◽  
MO Gallinari ◽  
PH dos Santos
Keyword(s):  
Hydrogen Peroxide ◽  
Deionized Water ◽  
Acetate Buffer Solution ◽  
Control Group ◽  
Buffer Solution ◽  
Tooth Whitening ◽  
Significance Level ◽  
Leucocrystal Violet ◽  
Peroxidase Enzyme ◽  
Visible Reflectance

SUMMARY The present study evaluated transenamel and transdentinal penetration of hydrogen peroxide during tooth whitening recognized in altered enamel by the presence of cracks or microabrasion. We used 72 experimental units (n=20) obtained from bovine incisors: GI-sound enamel; GII-teeth showing visible enamel cracks (4 mm to 5.7 mm in length); and GIII-microabrasioned enamel. The 12 remaining specimens were used to analyze the enamel surface morphology using scanning electron microscopy. The specimens were cylindrical and 5.7 mm in diameter and 3.5 mm thick. A product based on 35% hydrogen peroxide was used for bleaching, following the manufacturer's recommendations for use. To quantify the H2O2 penetration, the specimens were placed in artificial pulp chambers containing an acetate buffer solution. After bleaching, the solution was collected and adequately proportioned with leucocrystal violet, peroxidase enzyme, and deionized water. The resulting solution was evaluated using ultraviolet visible reflectance spectrophotometer equipment. The data were analyzed by analysis of variance (ANOVA) and Fisher's PLSD at a significance level of 0.05, and significant differences in the penetration of peroxide in different substrate conditions were observed (p&lt;0.0001). The penetration of hydrogen peroxide was more intense in cracked teeth. The group in which the enamel was microabraded showed intermediate values when compared to the control group. Microabrasion and the presence of cracks in the enamel make this substrate more susceptible to penetration of hydrogen peroxide during in-office whitening.

scholarly journals Penetration Capacity, Color Alteration and Biological Response of Two In-office Bleaching Protocols

2016 ◽  
Vol 27 (2) ◽  
pp. 169-175 ◽  
Author(s):  
Luciano Tavares Angelo Cintra ◽  
Francine Benetti ◽  
Luciana Louzada Ferreira ◽  
João Eduardo Gomes-Filho ◽  
Edilson Ervolino ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Statistical Tests ◽  
Biological Response ◽  
In Vitro Study ◽  
Control Group ◽  
Pulp Tissue ◽  
Dental Hard Tissues ◽  
Leucocrystal Violet ◽  
Color Alteration

Abstract Hydrogen peroxide (H2O2) penetrates into the dental hard tissues causing color alteration but also alterations in pulpal tissues. Hard-tissue penetration, color alteration and the pulp response alterations were evaluated for two in-office bleaching protocols with H2O2. For trans-enamel/dentin penetration and color alteration, discs of bovine teeth were attached to an artificial pulp chamber and bleached according to the groups: BLU (20% H2O2 - 1x50 min, Whiteness HP Blue); MAX (35% H2O2 - 3x15 min, Whiteness HP Maxx); Control (1x50 min, placebo). Trans-enamel/dentin penetration was quantified based on the reaction of H2O2 with leucocrystal violet and the color analyzed by CIELab System. Twenty Wistar rats were divided into two groups (BLU and MAX) and their maxillary right molars were treated according to the same protocols of the in vitro study; the maxillary left molars were used as controls. After 2 days, the animals were killed and their maxillae were examined by light microscopy. The inflammation of pulp tissue was scored according to the inflammatory infiltrate (1, absent; 2, mild; 3, moderate; 4, severe/necrosis). Data were analyzed by statistical tests (α=0.05). MAX showed higher trans-enamel/dentinal penetration of H2O2 (p<0.05). The color alteration was similar for both groups (p>0.05), and different when compared to Control group (p<0.05). MAX showed severe inflammation in the upper thirds of the coronal pulp, and BLU showed moderate inflammation (p<0.05). In-office bleaching protocols using lower concentrations of hydrogen peroxide should be preferred due to their reduced trans-enamel/dentinal penetration since they cause less pulp damage and provide same bleaching efficiency.

Enzymatic hydrolysis of chitosan in acetate buffer solution

2015 ◽  
Vol 88 (4) ◽  
pp. 647-651 ◽  
Author(s):  
V. V. Chernova ◽  
A. S. Shurshina ◽  
M. V. Bazunova ◽  
E. I. Kulish
Keyword(s):  
Enzymatic Hydrolysis ◽  
Acetate Buffer ◽  
Acetate Buffer Solution ◽  
Buffer Solution ◽  
Hydrolysis Of

scholarly journals Assessment of in Vitro Comparative Dissolution Kinetics of Moxonidine Products as a Factor Potentially Determining Effectiveness of Antihypertensive Treatment

2019 ◽  
Vol 14 (6) ◽  
pp. 951-957
Author(s):  
G. V. Ramenskaya ◽  
I. E. Shokhin ◽  
N. I. Gaponova ◽  
V. R. Abdrakhmanov
Keyword(s):  
Generic Drugs ◽  
Dissolution Kinetics ◽  
Acetate Buffer Solution ◽  
Medicinal Products ◽  
Buffer Solution ◽  
Reference Drug ◽  
Similarity Factor ◽  
Kinetics Of ◽  
Comparative Dissolution

Aim. Investigation of comparative dissolution kinetics of generic medicinal products containing moxonidine versus reference drug. Material and methods. Objects of the research were film-coated tablets containing moxonidine (INN) in a dose 0.4 mg: a reference drug Physiotens® and 4 generic drugs. In vitro dissolution test of moxonidine from the study drugs was performed using comparative dissolution kinetics test (CDKT). The CDKT was performed in the media with the following pH: 1.2 (1:9 mixture of 0.1 M hydrochloric acid and water), 4.5 (acetate buffer solution, prepared as per State Pharmacopoeia, XIII), and 6.8 (phosphate buffer solution, prepared as per State Pharmacopoeia, XIII). The sampling for dissolved moxonidine was performed 5, 10, 15, 20, and 30 min after the test was started. An high performance liquid chromatography method with ultraviolet detection at 220 nm was used to assay. Results. Within 15 min more that 85% of moxonidine dissolved from the reference drug and all study drugs at pH 1.2; dissolution profiles were similar without calculation of similarity factor f2. Similarly, at pH 4.5 dissolution profiles of study drugs #2 and #3 were similar to that of the reference drug, and the similarity factor f2 was not calculated. However, in case of study drugs #1 and #4 significant differences were observed at a single time point (15 min), which suggests that their dissolution profiles are non-similar to that of the reference drug. Similarity factors f2 were calculated 17.52 and 35.30, respectively (less than 50). At pH 6.8 similarity factors f2 for all study generic drugs were also less than 50 (23.8, 49.8, 38.6, and 35.9), so their dissolution curves were non-similar to that of reference drug. Conclusion. In our study we observed difference in release in vitro of medicinal products containing moxonidines: none of the study drugs was fully similar to the reference drug in all media. The differences observed at pH 6.8 were noteworthy, where the samples had or faster kinetics (study drugs #2 and #3), or slower dissolution kinetics (test drugs #1 and #4). Observed differences in moxonidine release rate may impact absorption of active pharmaceutical ingredient into the blood following drug administration.

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