Fluoride in toothpaste - is the expressed total fluoride content meaningful for caries prevention?

Examination of cytotoxic and antimicrobial effect of whitening toothpastes: an in vitro study

OBJECTIVE

Toothpastes are widely used to protect oral and teeth health. This study aims to examine the cytotoxic and antimicrobial effects of whitening toothpastes.

METHODS

In this study, extracts were prepared according to ISO 10993-12:2021 standard (0.2 g/mL) using whitening and conventional toothpastes. The prepared extracts were added to human gingival fibroblast cell lines (HGF-1) in different dilutions (1:1, 1:2, 1:4, 1:8, 1:16, and 1:32) and a cytotoxicity test was performed. Antimicrobial analysis of toothpastes was performed on Streptococcus mutans, Staphylococcus aureus, and Candida albicans using the hole-plate diffusion method. Cell viability and microbial analysis data were examined using two-way analysis of variance (ANOVA) and Tukey post-hoc test (p < 0.05).

RESULTS

Toothpastes with sodium lauryl sulfate (SLS) in their composition showed statistically more toxic effects (p < 0.05). The activated carbon toothpastes without SLS showed over 90% cell viability after dilution. Although the dilution rate of toothpastes containing SLS increased, cell viability remained below 70%. All toothpastes used in the study showed antimicrobial effects on S. mutans, S. aureus, and C. albicans. Toothpaste containing hydrogen peroxide and SLS produced more antibacterial effects than activated carbon, blue covarine, microparticles, and conventional toothpaste.

CONCLUSIONS

SLS-containing toothpastes showed more toxicity on HGF-1 cells. Toothpaste containing hydroxyapatite did not show toxic effects on HGF-1 cells. SLS, sodium lauryl sarcosinate and hydrogen peroxide in toothpastes increase antimicrobial effects.

Fluoride, pH Value, and Titratable Acidity of Commercially Available Mouthwashes

AIM

The primary objective of this work was to assess total soluble fluoride (TSF), pH values, and titratable acidity (TA) of various mouthwashes "in vitro," and the second was to compare fluoride content on labels with measured TSF.

METHODS

Commercial mouthwashes were collected and analysed. Company, type, manufacturer data, and active ingredients (essential oils [EO], cetylpyridinium chloride [CPC], chlorhexidine [CHX], and fluoride) were described. TSF, pH, and TA capacity were measured. Descriptive quantitative analysis were performed per mouthwash.

RESULTS

In total, 54 mouthwashes from 20 brands were included. These included mouthwashes with the active ingredients EO (n = 11), CPC (n = 17), CHX (n = 18), and fluoride (n = 32); 27 mouthwashes with more than 1 of these active ingredients; and 4 with none of the above-mentioned ingredients. Fluoride was present in different formulations; most contained sodium fluoride (NaF), and a few had sodium monofluorophosphate and amine fluoride + NaF. The pH values of all evaluated mouthwashes ranged from 4.1 to 7.9. Twenty mouthwashes presented pHs below 5.5, of which 10 contained fluoride. TA ranged from 0 to 48. According to the manufacturer data, mouthwashes with fluoride had concentrations from 217 to 450 ppm, with 90% in the range from 217 to 254 ppm. Laboratory data revealed that TSF ranged from 229 to 500 ppm, with 90% in the range from 229 to 337 ppm. A statistically significant difference was observed between measured TSF and the labelled fluoride content on the packaging of the fluoride mouthwashes (mean difference, 43.92 ± 34.34; P < .001). Most of these mouthwashes contained at least the amount of fluoride as mentioned on the packaging (93%).

CONCLUSION

The pH values and TA of commercially available mouthwashes showed a large variation. TSF levels of the fluoride mouthwashes were found to be at least the amount of fluoride as labelled. Dental care professionals should be aware of the pH, TA, fluoride content, and other active ingredients of different mouthwashes to better understand their potential impact on oral health.

Analysis of Covarine Particle in Toothpaste Through Microfluidic Simulation, Experimental Validation, and Electrical Impedance Spectroscopy

Covarine, copper phthalocyanine, a novel tooth whitening ingredient, has been incorporated into various toothpaste formulations using diverse technologies such as larger flakes, two-phase pastes, and microbeads. In this study, we investigated the behavior of covarine microbeads (200 μm) in Colgate advanced white toothpaste when mixed with artificial and real saliva. Our analysis utilized a custom-designed microfluidic mixer with 400 μm wide channels arranged in serpentine patterns, featuring a Y-shaped design for saliva and toothpaste flow. The mixer, fabricated using stereolithography 3D printing technology, incorporated a flexible transparent resin (Formlabs' Flexible 80A resin) and PMMA layers. COMSOL simulations were performed by utilizing parameters extracted from toothpaste and saliva datasheets, supplemented by laboratory measurements, to enhance simulation accuracy. Experimental assessments encompassing the behavior of covarine particles were conducted using an optical profilometer. Viscosity tests and electrical impedance spectroscopy employing recently developed all-carbon electrodes were employed to analyze different toothpaste dilutions. The integration of experimental data from microfluidic chips with computational simulations offers thorough insights into the interactions of covarine particles with saliva and the formation of microfilms on enamel surfaces.

The fluorosis conundrum: bridging the gap between science and public health

Fluorosis, a chronic condition brought on by excessive fluoride ingestion which, has drawn much scientific attention and public health concern. It is a complex and multifaceted issue that affects millions of people worldwide. Despite decades of scientific research elucidating the causes, mechanisms, and prevention strategies for fluorosis, there remains a significant gap between scientific understanding and public health implementation. While the scientific community has made significant strides in understanding the etiology and prevention of fluorosis, effectively translating this knowledge into public health policies and practices remains challenging. This review explores the gap between scientific research on fluorosis and its practical implementation in public health initiatives. It suggests developing evidence-based guidelines for fluoride exposure and recommends comprehensive educational campaigns targeting the public and healthcare providers. Furthermore, it emphasizes the need for further research to fill the existing knowledge gaps and promote evidence-based decision-making. By fostering collaboration, communication, and evidence-based practices, policymakers, healthcare professionals, and the public can work together to implement preventive measures and mitigate the burden of fluorosis on affected communities. This review highlighted several vital strategies to bridge the gap between science and public health in the context of fluorosis. It emphasizes the importance of translating scientific evidence into actionable guidelines, raising public awareness about fluoride consumption, and promoting preventive measures at individual and community levels.

A systematic review on the effect of silver diamine fluoride for management of dental caries in permanent teeth

OBJECTIVES

The objective of this review is to assess the available literature systematically related to the effect of silver diamine fluoride (SDF) for the management of occlusal and root carious lesions in permanent teeth regardless of age. MATERIALS AND METHODS: This systematic review was conducted according to the Cochrane Handbook for Systematic Reviews of Interventions and Preferred Reporting Items for Systematic Review and Meta-Analyses statement. A literature search was performed using PubMed/MEDLINE, Cochrane Central Register of Controlled Trials, Web of Science, DOAJ, and Open Gray with no language restrictions up to December 2022. Three reviewers critically assessed the studies for eligibility. Any disputes between the reviewers were handled by a fourth independent reviewer. The quality assessment and data extraction of the studies were performed.

RESULTS

A total of 2176 studies were screened. The titles and abstracts of the studies were then reviewed (n = 346), and 52 studies met the search criteria. Following the full-text review, 11 studies investigated the effect of SDF against other treatments such as chlorhexidine, sodium fluoride, ammonium bifluoride, tricalcium silicate paste, casein phosphopeptide amorphous calcium phosphate, glass ionomer cement (GIC) combined with fluoride varnish, resin-modified GIC, and atraumatic restorative treatment were assessed.

CONCLUSIONS

Within the limitations of this review, the use of SDF is promising with high preventative fractions in permanent teeth of children and older populations when compared to other topical applications such as dental varnish containing sodium fluoride.

Fluoride content in paediatric dentifrices commercialized in Brazil

OBJECTIVES

The aim of this study is to determine the total, soluble and ionic fluoride (IF) concentration in toothpastes for children since there is a lack of information about this data.

METHODS

Fifteen different brands of toothpastes were purchased in different cities in Brazil. The total fluoride (TF), total soluble fluoride (TSF) and IF of two samples of each brand were determined (μg/g F).

RESULTS

The concentration of TF found in the fluoride toothpastes ranged from 324.4 to 1466.2 μg/g F, TSF ranged from 214.6 to 1424.1 μg/g F and IF ranged from 108.3 to 1320.1 μg/g F. TSF ranged between TF and IF. Most toothpastes were formulated with sodium fluoride (NaF), and only one with monofluorophosphate (MFP). The concentrations of TF were below the reported values. TSF and IF were below the TF concentration.

CONCLUSIONS

The measured TF was less than that declared by the manufacturer in all the products. Most of the evaluated fluoride toothpastes commercialized in Brazil showed concentrations of TF below what was stated on the packaging, but with enough TSF to provide an anti-caries effect.

Fluoride concentration in dentifrices marketed In Argentina

OBJECTIVES

The objective of this study was to determine the different forms of fluoride available in dentifrices commercialized in Argentina.

METHODS

Thirty three different brands of fluoridated dentifrices were purchased in different cities of Argentina. The total fluoride (TF), total soluble fluoride (TSF) and ionic fluoride (IF) of two samples of each brand were analysed (μg F/ml) by ion-specific fluorine electrodes.

RESULTS

A total of 67% of dentifrices showed fluoride content that compromises anti-caries activity. A total of 54.5% was formulated with sodium fluoride (NaF), 36.3% formulated with sodium monofluorophosphate (MFP), 3% NaF associated with MFP and 9% formulated with stannous fluoride (SnF2). The TF found was less than the amount declared by the manufacturer in all the brands analysed. The concentration of TF found in the fluoride dentifrices ranged from 590.3 to 1381.4 μg/ml F, TSF ranged from 343.1 to 1258.3 μg/ml F, and IF ranged from 13.1 to 913 μg/ml F.

CONCLUSION

The concentrations of TF were below the reported values. TSF and IF were lower than the total fluoride concentration. Most of the samples studied have TSF concentration that compromises anti-caries effect. Additional studies with a larger number of samples are suggested to obtain more data.

In Vitro Biocompatibility of Several Children's Toothpastes on Human Gingival Fibroblasts

The European Academy of Paediatric Dentistry has recommended fluoride toothpastes from the eruption of the first teeth in children. Toothpastes stay in the mouth in contact with human gingival fibroblasts (hGFs) for a long time. Thus, the objective of this study was to compare the cytotoxicity of five different commonly used children’s toothpastes: Oral B Kids +3 (Procter & Gamble, Alicante, Spain), Fluor Kin Calcium (Kin, Madrid, Spain), PHB Junior (PHB, Barcelona, Spain), Colgate +3 (Colgate Palmolive, Madrid, Spain) and Vitis Kids (Dentaid, Valencia, Spain) on hGFs. The children’s toothpastes were exposed to hGFs at different concentrations (1:1, 1:2, 1:4). Afterwards, several tests were performed: MTT assays, cell cycle analyses, cell cytoskeleton staining assays, apoptosis/necrosis assays, and ICP-MS and ion chromatography. Oral B displayed the lowest cytotoxicity and was the toothpaste with the highest fluoride ion release; meanwhile, the other toothpastes were cytotoxic (*** p < 0.0001); Fluor Kin being the one with the lowest fluoride ion release. Among all the toothpastes analyzed, Oral B exhibited the best results in vitro in terms of biocompatibility. Future evaluations, both in vitro and in vivo, are required to confirm the biocompatibility of sodium lauryl sarcosinate and sodium lauryl sulfate containing toothpastes.

Formulation and fluoride content of dentifrices: a review of current patterns

Introduction Consumer oral hygiene products play a key role in improving and maintaining population oral health. The oral personal care market is rapidly diversifying; a growing number of dentifrices marketed a 'natural' and fluoride-free are entering mainstream retailers, which may have implications for the oral health of the population 'with regards to caries risk.Aims To investigate the range of fluoride concentrations, flavour formulations and delivery mechanisms of dentifrices available on the UK market.Methods A cross-sectional survey was used to catalogue dentifrices sold in a range of supermarkets, high-street pharmacy and health chains, and specialist online retailers. In addition, a standard search engine was used to examine dentifrice brands being sold in the UK. The fluoride content was recorded as parts per million (ppm) and the product name data were analysed for key terms using Microsoft Excel. Excluded from the survey were mouthwashes, rinses and non-dentifrice whitening products.Results Five hundred different toothpaste, tooth powder and tablet products from 95 different brands were recorded. Sixty percent of these contained a fluoride concentration of 1,000 ppm or above. Forty-five percent of all products had the recommended adult concentration of at least 1,350 ppm. Almost one-third (31%) contained no fluoride and 4% of products did not specify the absence, presence or concentration of fluoride.Conclusions This study has quantified and confirmed the increasingly diverse range of dentifrices for sale in the UK. A large number of fluoride-free products exist within a growing 'natural' and 'organic market'. The study also gives oral health professionals an insight into the diverse types of products available to consumers in order to appropriately advise patients on caries prevention.