Calcium-Polyphosphate Submicroparticles (CaPP) Improvement Effect of the Experimental Bleaching Gels' Chemical and Cellular-Viability Properties

The aim of this research was to develop and characterize the chemical and cellular-viability properties of an experimental high-concentration bleaching gel (35 wt%-H2O2) containing calcium-polyphosphate particles (CaPP) at two concentrations (0.5 wt% and 1.5 wt%). The CaPP submicroparticles were synthesized by coprecipitation, keeping a Ca:P ratio of 2:1. The CaPP morphology, size, and chemical and crystal profiles were characterized through scanning and transmission electron microscopy, energy-dispersive X-ray analysis, and X-ray diffraction, respectively. The assessed bleaching gels were experimental (without CaPP); 0.5% CaPP; 1.5% CaPP; and commercial. The gels’ pH values and H2O2 concentrations (iodometric titration) were determined. The odontoblast-like cell viability after a gel’s exposure was assessed by the MTT assay. The pH and H2O2 concentration were compared through a repeated-measures analysis of variance (ANOVA) and a Tukey’s test and the cell viability through a one-way ANOVA and a Tukey’s test using a GraphPad Prism (α < 0.05). The CaPP particles were spherical (with Ca and P, 135.7 ± 80.95 nm size) and amorphous. The H2O2 concentration decreased in all groups after mixing (p < 0.001). The 0.5% CaPP resulted in more-stable pH levels and higher viability levels than the experimental one (p < 0.05). The successful incorporation of CaPP had a positive impact on the bleaching gel’s chemical and cellular-viability properties when compared to the experimental gel without these particles.

Nanoparticles as Next-Generation Tooth-Whitening Agents: Progress and Perspectives

Whitening agents, such as hydrogen peroxide and carbamide peroxide, are currently used in clinical applications for dental esthetic and dental care. However, the free radicals generated by whitening agents cause pathological damage; therefore, their safety issues remain controversial. Furthermore, whitening agents are known to be unstable and short-lived. Since 2001, nanoparticles (NPs) have been researched for use in tooth whitening. Importantly, nanoparticles not only function as abrasives but also release reactive oxygen species and help remineralization. This review outlines the historical development of several NPs based on their whitening effects and side effects. NPs can be categorized into metals or metal oxides, ceramic particles, graphene oxide, and piezoelectric particles. Moreover, the status quo and future prospects are discussed, and recent progress in the development of NPs and their applications in various fields requiring tooth whitening is examined. This review promotes the research and development of next-generation NPs for use in tooth whitening.

The Use of Calcium Phosphates in Cosmetics, State of the Art and Future Perspectives

Calcium phosphates (CaPs) belong to a class of biomimetic materials widely employed for medical applications thanks to their excellent properties, such as biodegradability, biocompatibility and osteoinductivity. The recent trend in the cosmetics field of substituting potentially hazardous materials with natural, safe, and sustainable ingredients for the health of consumers and for the environment, as well as the progress in the materials science of academics and chemical industries, has opened new perspectives in the use of CaPs in this field. While several reviews have been focused on the applications of CaP-based materials in medicine, this is the first attempt to catalogue the properties and use of CaPs in cosmetics. In this review a brief introduction on the chemical and physical characteristics of the main CaP phases is given, followed by an up-to-date report of their use in cosmetics through a large literature survey of research papers and patents. The application of CaPs as agents in oral care, skin care, hair care, and odor control has been selected and extensively discussed, highlighting the correlation between the chemical, physical and toxicological properties of the materials with their final applications. Finally, perspectives on the main challenges that should be addressed by the scientific community and cosmetics companies to widen the application of CaPs in cosmetics are given.

A review on dental whitening

OBJECTIVES

To provide a narrative review on vital dental whitening chemistry, toxicity and safety, vital dental whitening techniques, whitening systems, potential side effects of whitening and cyclic whitening using products with a range of concentrations and pH values. In addition, new developments and recommendations in the field of vital dental whitening will be presented to help clinicians understand the whitening process, its advantages, limitations, and the impact of whitening concentration and pH on enamel providing guidance in tailoring whitening treatments.

DATA

Data were gathered using the following keywords: dental whitening, roughness, hardness, sensitivity, hydrogen peroxide, whitening pH, whitening concentration, whitening chemistry, colour, and toxicity.

SOURCES

An electronic search was performed using PubMed and Scopus databases. Bibliographic material from papers reviewed was then used to find other relevant publications.

CONCLUSIONS

The effectiveness of vital dental whitening depends on many factors, such as the concentration/pH of the whitening agent, application duration, chemical additives, and re-mineralising agents used. Developing new whitening products and technologies such as nano-additives and alternative carrier systems is showing promising results, and might prove efficient in maximising whitening benefits by accelerating the whitening reaction and/or minimising expected reversible/irreversible enamel structural damage.

Influence of Different Time Intervals among the in-Office Bleaching Sessions on the Tooth Enamel Mass Variation

AbstractThis study evaluated the effect of different time intervals between tooth bleaching sessions on the variation of tooth enamel mass, using a 35% hydrogen peroxide (HP35) gel. Twenty bovine incisor teeth were collected and cross-sectioned twice, leaving only the middle coronal portion. The dentin layer was removed, leaving only the buccal dental enamel. The samples were randomly divided into 2 groups (n = 10): G1 (with a 7-day time interval between each bleaching session), and G2 (with a 2-day time interval between each bleaching session). Three bleaching sessions were performed for each group. Each specimen’s mass was measured using an electronic analytical scale, first at the beginning of the experiments (T0), and then immediately after each bleaching intervention (T1, T2 and T3, respectively). All samples were stored in artificial saliva and kept in a biological chamber during the time of the study. The data analysis was performed using ANOVA for the related samples (p = 0.05). The results showed a reduction in the enamel mass values in G2 after the 3rd session when comparing to enamel mass values presented at the beginning of the study. On the other hand, G1 presented an increase in the mass values at the end of the third session, and these intragroup differences were statistically significant (p <0.001). It was concluded that bleaching treatment with 7-day intervals between sessions leads to no tooth enamel mass loss, whereas the reduced 2–day time interval between sessions caused a significant tooth enamel mass loss. Keywords: Tooth. Tooth Bleaching. Tooth Enamel. Resumo                                                                 Este estudo avaliou a influência de diferentes intervalos de tempo entre as sessões de clareamento com peróxido de hidrogênio a 35% (PH35) sobre a variação de massa do esmalte dental. Foram utilizados 20 dentes incisivos bovinos hígidos, seccionados em duas porções transversais, com a camada de dentina vestibular toda removida, restando apenas o esmalte dental vestibular. As amostras foram distribuídas em 2 grupos (n=10): G1 - intervalo de tempo de 7 dias entre as sessões de clareamento, e G2 - Intervalo de 2 dias entre as sessões de clareamento. Foram realizadas 3 aplicações de gel clareador em cada grupo. A pesagem dos espécimes foi realizada antes do início do tratamento clareador e ao final de cada intervenção clareadora, em uma balança analítica eletrônica. Os espécimes foram armazenados em saliva artificial, e mantidos em estufa biológica. Os dados foram submetidos à ANOVA para amostras relacionadas (p=0.05). O G2 apresentou uma redução nos valores de massa do esmalte quando comparados os tempos antes do clareamento (T0 - 0.1650g) e após a 3° sessão (T3 - 0.1643g). Entretanto, o G1 apresentou um aumento nos valores de massa ao término da terceira sessão (T0 - 0.1615g e T3 - 0.1624g), sendo essas diferenças intragrupos estatisticamente significantes (p<0.001). Foi possível concluir que no clareamento com intervalo de 7 dias entre as sessões não houve perda de massa do esmalte dental, ao passo que quando reduzido o intervalo entre as sessões para 2 dias, uma perda significativa de massa foi observada. Palavras-chave: Dente. Clareamento Dental. Esmalte Dentário.

Effects of in-office bleaching agent combined with different desensitizing agents on enamel

OBJECTIVE

To analyze color change, microhardness and chemical composition of enamel bleached with in-office bleaching agent with different desensitizing application protocols.

MATERIALS AND METHODS

One hundred and seventeen polished anterior human enamel surfaces were obtained and randomly divided into nine groups (n = 13). After recording initial color, microhardness and chemical composition, the bleaching treatments were performed as G1: Signal Professional White Now POWDER&LIQUID FAST 38% Hydrogen peroxide(S); G2: S+Flor Opal/0.5% fluoride ion(F); G3: S+GC Tooth Mousse/Casein Phosphopeptide-Amorphous Calcium Phosphate (CPP-ACP) paste(TM); G4: S+UltraEZ/3% potassium nitrate&0.11% fluoride(U); G5: S+Signal Professional SENSITIVE PHASE 1/30% Nano-Hydroxyapatite (n-HAP) suspension(SP); G6: S-F mixture; G7: S-TM mixture; G8: S-U mixture; G9: S-SP mixture. Color, microhardness and chemical composition measurements were repeated after 1 and 14 days. The percentage of microhardness loss (PML) was calculated 1 and 14 days after bleaching. Data were analyzed with ANOVA, Welch ANOVA, Tukey and Dunnett T3 tests (p<0.05).

RESULTS

Color change was observed in all groups. The highest ΔE was observed at G7 after 1 day, and ΔE at G8 was the highest after 14 days (p<0.05). A decrease in microhardness was observed in all groups except G6 and G7 after 1 day. The microhardness of all groups increased after 14 days in comparison with 1 day after bleaching (p>0.05). PML was observed in all groups except G6 and G7 after bleaching and none of the groups showed PML after 14 days. No significant changes were observed after bleaching at Ca and P levels and Ca/P ratios at 1 or 14 days after bleaching (p>0.05). F mass increased only in G2 and G6, 1 day after bleaching (p<0.05).

CONCLUSIONS

The use of desensitizing agents containing fluoride, CPP-ACP, potassium nitrate or n-HAP after in-office bleaching or mixed in bleaching agent did not inhibit the bleaching effect. However, they all recovered microhardness of enamel 14 days after in-office bleaching.