Related Experiment Video
Updated: Jan 21, 2026
10:27
Training Synesthetic Letter-color Associations by Reading in Color
Published on: February 20, 2014
23.3K
Decomposition Rate, pH, and Enamel Color Alteration of At-Home and In-Office Bleaching Agents
Vanessa Cavalli1, Bruna Guerra da Silva1, Sandrine Bittencourt Berger2
1Department of Restorative Dentistry, Piracicaba Dental School, UNICAMP - Universidade Estadual de Campinas, Piracicaba, SP, Brazil.
Brazilian Dental Journal
|July 25, 2019
Summary
At-home and in-office bleaching agents show varying decomposition rates and pH levels. Higher concentrations of carbamide peroxide (CP) resulted in greater color alteration, with in-office hydrogen peroxide (HP) agents effective in a single application.
Area of Science:
- Dental materials science
- Biomaterials
- Cosmetic dentistry
Background:
- Dental bleaching is a common cosmetic procedure.
- Understanding the chemical and physical properties of bleaching agents is crucial for efficacy and safety.
- Carbamide peroxide (CP) and hydrogen peroxide (HP) are the primary active ingredients in dental bleaching.
Purpose of the Study:
- To evaluate the decomposition rate (DR), pH, enamel color alteration (DE), and whiteness index (DWI) of at-home and in-office bleaching agents.
- To compare the effects of different concentrations of CP and HP, as well as light irradiation during in-office bleaching.
Main Methods:
- Enamel surfaces were treated with various at-home (10%, 15%, 20% CP; 6% HP) and in-office (35% HP with/without light) bleaching agents.
- DR and pH were measured at specific time intervals.
- Color parameters (L*, a*, b*, DE, DWI) were assessed before and after bleaching.
- Statistical analysis included one-way/two-way repeated measures ANOVA and Tukey tests.
Main Results:
- At-home CP agents showed similar DR after 6-8 hours, with pH ranging from neutral (CP) to acidic (6% HP).
- Higher CP concentrations (15%, 20%) led to greater DE than 10% CP after 4-8 hours.
- In-office 35% HP agents demonstrated significant DE in one application, irrespective of light irradiation, with varying pH levels.
- No significant differences in DWI were observed among groups, indicating a general whitening effect.
Conclusions:
- At-home bleaching agents can be applied for 2-4 hours depending on concentration and type.
- In-office 35% HP agents are effective within a single 40-minute application without light.
- Agent concentration and pH are key factors influencing bleaching efficacy and potential enamel alteration.
Related Concept Videos
02:17Synthesis and Decomposition Reactions
38.1K
Synthesis and decomposition are two types of redox reactions. Synthesis means to make something, whereas decomposition means to break something. The reactions are accompanied by chemical and energy changes.
38.1K
03:09Measuring Reaction Rates
28.7K
Polarimetry finds application in chemical kinetics to measure the concentration and reaction kinetics of optically active substances during a chemical reaction. Optically active substances have the capability of rotating the plane of polarization of linearly polarized light passing through them—a feature called optical rotation. Optical activity is attributed to the molecular structure of substances. Normal monochromatic light is unpolarized and possesses oscillations of the electrical...
28.7K
03:08Rate-Determining Steps
36.8K
Relating Reaction Mechanisms
In a multistep reaction mechanism, one of the elementary steps progresses significantly slower than the others. This slowest step is called the rate-limiting step (or rate-determining step). A reaction cannot proceed faster than its slowest step, and hence, the rate-determining step limits the overall reaction rate.
The concept of rate-determining step can be understood from the analogy of a 4-lane freeway with a short-stretch of traffic-bottleneck caused due to...
In a multistep reaction mechanism, one of the elementary steps progresses significantly slower than the others. This slowest step is called the rate-limiting step (or rate-determining step). A reaction cannot proceed faster than its slowest step, and hence, the rate-determining step limits the overall reaction rate.
The concept of rate-determining step can be understood from the analogy of a 4-lane freeway with a short-stretch of traffic-bottleneck caused due to...
36.8K
03:02Colors and Magnetism
14.0K
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
14.0K
01:24Color Vision
1.4K
Color perception begins in the retina, the light-sensitive layer at the back of the eye. Two main theories explain how colors are seen: the trichromatic theory and the opponent-process theory. The trichromatic theory, proposed by Thomas Young in 1802 and extended by Hermann von Helmholtz in 1852, suggests that color vision is based on three types of cone receptors in the retina. These cones are sensitive to different but overlapping ranges of wavelengths corresponding to red, blue, and green.
1.4K
01:30Alterations in Respiration II
1.7K
There are numerous types of normal and abnormal respiration. Based on ventilatory movements, breathing patterns are classified as regular, deep, or shallow. Examples include Biot's breathing, Cheyne-Stokes respiration, Kussmaul's breathing, hyperventilation, and hypoventilation. Each pattern is clinically significant and aids in evaluating patients.
In Biot's breathing, the respiratory rate and depth are irregular, alternating between periods of deep gasping and apnea. Common causes...
In Biot's breathing, the respiratory rate and depth are irregular, alternating between periods of deep gasping and apnea. Common causes...
1.7K