Effect of temperature and storage time on dental bleaching effectiveness

Abstract

Objective To evaluate the effect of storage time and temperature on the effectiveness of bleaching agents. Methods Enamel slabs were randomly allocated according to the concentration of carbamide peroxide (CP): 10% (CP10) and 16% (CP16). Shade evaluations were conducted at baseline and then after 3 and 12 months of storage at 3 different temperatures: 10°C (±2°C), 25°C (±2°C), and 35°C (±2°C). Objective color evaluation was performed (spectrophotometer CIEL*a*b* system and CIEDE2000) to calculate the color change (ΔE00). Subjective evaluation was performed using the VITA classical shade guide followed by shade variation (ΔS). Results The bleaching effect of different CP concentrations (10% and 16%) at baseline showed no differences with regard to objective (ΔE00) and subjective parameters (ΔS) (P > .05). No differences were observed between CP concentrations stored for the same length of time and at the same temperature for either parameter (P > .05). In terms of objective measurement (ΔE00), a reduction in the bleaching effect was shown for both CP concentrations (10% and 16%) when stored for 12 months at 35°C, and compared with the baseline (P < .05). As regards the subjective parameters (ΔS), after 12 months, both CP concentrations (10% and 16%) stored at 35°C showed a decrease in bleaching capacity compared to baseline (P < .05). CP10 and CP16 stored at 10°C and 25°C did not suffer any loss in bleaching ability, even after 12 months (P > .05). Conclusions The storage of bleaching agents for long periods at high temperatures can reduce the bleaching effectiveness of CP at 10% and 16%. Clinical Significance Clinicians must be made aware that they should store their bleaching products under proper temperature conditions and use them within an appropriate time frame; otherwise, the bleaching effect could be lost.

Color change, diffusion of hydrogen peroxide, and enamel morphology after in‐office bleaching with violet light or nonthermal atmospheric plasma: An in vitro study

“…Thus, VL was more effective for removing red and yellow polyphenolic chromophores present in tea, reinforcing the theory that violet wavelength would interact with external discoloration . In addition, staining methods have been extensively used in several bleaching studies in order to standardize color parameters . In this sense, a * and b * variations indicated that changes promoted in the control could have been caused by the detachment of staining molecules during artificial saliva storage, but this group presented statistically lower color change in comparison with the others.…”

Desire of university students for esthetic treatment and tooth bleaching

“…Change in tooth color may occur due to a natural process of dental aging or may be caused by oral diseases, dental trauma or by the use of dental material such as mineral trioxide aggregate [7][8][9][10] . Moreover, tooth discoloration may also be due to extrinsic pigmentation, which occurs with the consumption of highly pigmented foods and also tobacco use 11 .…”

Dentist’s preferences on vital and nonvital tooth bleaching

“…Although the literature showed that while different concentration agents exhibit similar efficacy 12 , the use of therapies with lower peroxide concentration has been recommended as the first choice because they usually are associated with less sensitivity during treatment 19 . Moreover, an in vitro study showed that higher concentrations of peroxide in bleaching materials can degrade more easily than peroxides with lower concentrations and thus affect its effectiveness 8 . In fact, 60.5% of dentists choose the in-office protocol, of which 50% indicated CP 37% or HP 37% and 10.5% indicated the CP 10-22%, concentrations used to at-home.…”

“…These products are mainly based on hydrogen peroxide (HP) or carbamide peroxide (CP), which breaks down into HP and urea. These oxidizing chemical agents can be used for vital or nonvital tooth bleaching; while sodium perborate (SP) is used exclusively for nonvital tooth bleaching [8][9][10] . Moreover, low concentration agents [10-22% CP and 6% HP] are used at home by the patients under professional supervision, which is defined as an at-home technique; and high concentrations [>30% CP or HP] are applied only in the dental office by the dentist in the so-called in-office technique 11 .…”