Effects of dentifrices containing activated charcoal on dental enamel: a review of the literature / Efeitos de dentifrícios contendo carvão ativado no esmalte dental: uma revisão da literatura

ABSTRACT The increased demand for white teeth has intensified the commercialization of new bleaching products, particularly those that can be accessed easily, do not require the direct supervision of a dentist, and are affordable. Among these new products, several dentifrices publicized as bleaching products have been developed, most recent of them being the activated charcoal toothpaste, which entered the market promising to whiten teeth. While it is portrayed as a healthy and ecological product, there is a paucity of scientific evidence supporting its alleged benefits. Therefore, this literature review aimed to evaluate activated charcoal containing oral hygiene products on their bleaching ability and effects on enamel. After analyzing several in vitro studies on the subject, it can be concluded that these products do not have a bleaching effect per se, but act by removing the extrinsic pigments from the teeth. However, most of the products containing activated charcoal could have abrasive effects on the surface of the enamel. Therefore, it is suggested caution about the indication of these dentifrices, especially for individuals predisposed to dental wear, such as gingival recession, reduced salivary flow, and high risk of caries or dental erosion.

RESUMO A maior procura por dentes brancos tem impulsionado a comercialização de novos produtos clareadores, especialmente aqueles que possam ser de fácil acesso, que não precisem supervisão direta do dentista, e que tenham um custo acessível para o consumidor. Entre esses novos produtos diversos dentifrícios, denominados como branqueadores, têm sido comercializados. Destes o mais recente é o dentifrício a base de carvão ativado, que entrou no mercado prometendo clarear os dentes, enquanto que se apresenta como um produto saudável e ecológico, porém sem grande respaldo científico. Portanto, esta revisão da literatura teve o objetivo de avaliar a capacidade branqueadora e os efeitos no esmalte após o uso de produtos de higiene oral contendo carvão ativado. Após avaliar diversos artigos in vitro sobre o tema, pode-se concluir que estes produtos não tem um efeito clareador propriamente dito e sim agem como removedores de pigmentos extrínsecos. Porém, grande parte dos produtos contendo carvão ativado poderiam apresentar um efeito abrasivo sobre a superfície do esmalte, pelo que se sugere cautela sobre a indicação destes dentifrícios, especialmente para os pacientes sujeitos a maiores riscos de desgaste dental, como recessão gengival, fluxo salivar reduzido, alto risco de cárie ou erosão dentária.

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.

Effect of Different Bleaching Gels Thickeners on Cytotoxicity to Human Gingival Fibroblasts and Enamel Physical Properties: an in Situ Study.

Objective: This study evaluated in vitro, the effects of carbamide peroxide 10% (CP) associated with Carbopol® (CP-ct) and Aristoflex® (CP-at) thickeners on human gingival fibroblasts (HGF) cytotoxicity and assessed in situ their effects on dental enamel. Material and methods: The cytotoxicity was analyzed using MTT - Vybrant® proliferation test. For in situ stage, 144 bovine enamel/dentin blocks were randomized into seven groups (n=12). Samples were stained, fixed in intraoral palatal devices and bleached for 4 h, during 14 days, with: Carbopol thickener (ct), Aristoflex thickener (at), CP-ct, CP-at, CP without thickener (CP-wot), Commercial CP (CP-com). The samples had their microhardness (SMH), roughness (Ra) and color analyzed using a microdurometer, a rugosimeter and a spectrophotometer, respectively. The analyses were performed at baseline and 24-h after completion of tooth bleaching. Results: Different thickeners were similar regarding their cytotoxicity. The experimental gels with Carbopol exhibited lower SMH values, while the groups treated with CP exhibited higher Ra values. For the color change results, the groups treated with CP had values above the acceptability and perceptibility limits. Conclusion: CP-at was able to promote an effective bleaching with less alterations of the tooth surface compared to the CP-ct. Hence, Aristoflex stands as a promising thickener in conjunction with CP in order to preserve the physical properties of dental enamel after home bleaching.

Effect of the casein phosphopeptide-amorphous calcium phosphate fluoride (CPP-ACPF) and photobiomodulation (PBM) on dental hypersensitivity: A randomized controlled clinical trial.

OBJECTIVE: This randomized controlled clinical trial aimed to evaluate the effect of the casein phosphopeptide-amorphous calcium phosphate fluoride (CPP-ACPF) and photobiomodulation (PBM) in the treatment of dentin hypersensitivity (DH), and the impact of this on the health-related quality of life (HRQL). METHODS: Eighty teeth with DH were randomized into four groups and received three treatment sessions: PLACEBO = placebo + LASER application mimicking; CPP-ACPF = CPP-ACPF + LASER application mimicking; PBM = placebo + LASER active application; CPP-ACPF+PBM = CPP-ACPF + LASER active application. Tactile (exploratory probe) and evaporative (triple syringe) stimuli were used to measure DH and were recorded with the aid of a visual analogue scale (VAS) after the 1st, 2nd and 3rd treatment sessions and one-month follow-up. The HRQL was recorded in the DH experience questionnaire (DHEQ). RESULTS: The intragroup comparison showed a significant reduction in DH (p < 0.05) with both stimuli after one-month follow-up. The intergroup comparison with the evaporative stimulus showed that CPP-ACPF+PBM significantly reduced DH when compared to the rest of treatments, after one-month follow-up. CPP-ACPF+PBM group statistically differed from the other treatment groups in the DHEQ evaluation after one-month follow-up. CONCLUSION: After one-month follow-up, the association of CPP-ACPF with PBM was effective in the reduction of DH and promoted a positive impact on the HRQL of the participants of this study.

Clinical efficacy of nano-hydroxyapatite in dentin hypersensitivity: A systematic review and meta-analysis.

OBJECTIVES: To evaluate the desensitizing effect of nano-hydroxyapatite (n-HAP) on dentine hypersensitivity (DH). SOURCES: Seven electronic databases were searched on April 27, 2018. STUDY SELECTION: Randomized clinical trials (RCTs) were included based on the PICO strategy: Participants - Humans with DH; Intervention - n-HAP-containing desensitizing; Comparison -n-HAP-free treatments or placebo/negative control; and Outcomes - relief of DH. The risk of bias was classified by the Cochrane guidelines. Five meta-analyses were performed to evaluate the efficacy of n-HAP with regard to pain assessment stimuli (primary outcome); comparison of n-HAP with other treatments or placebo/negative control, and effectiveness of at-home and in-office n-HAP use (secondary outcomes). The quality of the evidence was evaluated using the GRADE. DATA: Six RCTs with 4 weeks of follow-up were included in the meta-analysis. For the primary outcome, n-HAP showed a better desensitizing effect for evaporative stimuli (SMD -1.09 [-1.24, -0.94], p < 0.00001) and tactile stimuli (SMD -0.93 [-1.42, -0.43]) than other treatments (p = 0.0002). However, there was no difference between n-HAP and other treatments for the cold stimuli (SMD -0.17 [-0.81, 0.48], p = 0.61). In an overall analysis, n-HAP-containing treatment showing the most significant desensitizing effect (SMD -0.93 [-1.19, -0.68], p < 0.00001) with a high quality of evidence for pooled results. In the secondary outcomes, n-HAP showed the best effect in the overall analysis (p < 0.05) with moderate quality evidence. CONCLUSIONS: The n-HAP-containing treatment showed better clinical performance than other treatments for DH relief. However, long-term follow-up RCTs are required in the future before definitive recommendations can be made. CLINICAL SIGNIFICANCE: Dentin hypersensitivity is a common global condition and its multifactorial etiology has led to the development of several treatments. The n-HAP-containing treatment showed greater DH relief when compared to other desensitizing agents, placebo or negative control.