The effects of toothpaste amounts and post-brushing rinsing methods on salivary fluoride retention

Kinetics of fluoride after brushing with the no-rinse method

BACKGROUND

Fluoride plays a vital role in preventing dental caries, with its addition to oral care products significantly promoting oral hygiene. A no-rinse brushing method aims to increase fluoride retention in the oral cavity, as rinsing with water decreases fluoride levels in saliva, which could affect remineralization. While the no-rinse brushing method holds promise for improving fluoride retention in the oral cavity, critical inquiries persist regarding its safety. This study investigated the kinetics of oral fluoride and potential risks to fully assess its effectiveness and implications for oral health.

METHODS

Ten healthy adults participated in a crossover study comparing the no-rinse with the rinse method. All subjects followed American Dental Association (ADA) brushing guidelines. Levels of fluoride in saliva (supernatant and sediment) and urine were measured over time, and plasma fluoride was measured one hour after brushing. Pharmacokinetic parameters were also calculated from the data.

RESULTS

Participants using the no-rinse method had higher fluoride levels in supernatant immediately and up to 30 min post-brushing compared to the rinse method. Fluoride levels in sediment were higher only immediately after brushing. The total fluoride concentration in saliva remained elevated for up to 5 min with the no-rinse method. Systemic fluoride absorption showed no significant difference between the two methods based on blood and urine analysis.

CONCLUSION

This research indicates that the no-rinse method can enhance fluoride retention in the oral cavity for up to 30 min after a single brushing. In addition, our findings suggest that this method does not significantly influence systemic fluoride levels or toxicity.

REGISTRY

Thai Clinical Trials Registry, TCTR ( http://thaiclinicaltrials.org ).

CLINICAL TRIAL REGISTRATION NUMBER

TCTR20231104001 (4/11/2023).

Oral Health Knowledge, Self-Assessed Oral Health Behavior, and Oral Hygiene Practices among the Adult General Population in Croatia

OBJECTIVES

Emphasizing the significance of optimal oral health for enhancing overall well-being, this study aimed to investigate oral health knowledge, self-assessed oral health behaviors, and oral hygiene practices within the Croatian general population.

MATERIALS AND METHODS

A cross-sectional observational study was conducted online, utilizing a questionnaire collecting sociodemographic characteristics and inquiring about respondents' oral health knowledge, self-assessed oral health status, oral hygiene habits, and use of oral hygiene products. Collected data underwent both descriptive and regression analyses to unveil patterns and relationships within the dataset.

RESULTS

The respondents showed a high level of knowledge about oral health (median score 9, IQR 7.00-10.00, maximum possible score 10), with significant factors for higher knowledge being engaged in dental professions; above-average socioeconomic status; and the use of an electric brush, dental floss, and interdental brushes (p ˂ 0.05). Insufficient knowledge, on the other hand, was associated with bleeding gums and daily smoking (p ˂ 0.05). Although 69.4% of respondents considered their oral health to be very good, 32.5% reported tooth decay, and 38.2% reported tooth sensitivity. The majority (62.0%) cited regular check-ups as the reason for their last visit to the dentist, with 74.1% feeling no anxiety or discomfort during these visits. Daily toothbrush use was widespread (97.8%), but only 34.1% and 19.1% of respondents reported using floss and/or interdental brushes daily. A remarkable 69.0% of respondents indicated that low oral health literacy and low prioritization contribute to suboptimal oral health.

CONCLUSIONS

While respondents demonstrated commendable oral health knowledge, the prevalence of reported issues suggests a potential gap between perception and actual oral health status. To address this, targeted educational interventions focusing on comprehensive oral hygiene practices and debunking misconceptions should be prioritized in Croatia.

Salivary fluoride concentrations following toothbrushing with experimental toothpaste containing surface pre-reacted glass-ionomer (S-PRG) filler

BACKGROUND

Single-blind 9 case comparative studies were conducted to evaluate salivary fluoride concentrations following toothbrushing using experimental toothpaste containing surface pre-reacted glass-ionomer (S-PRG) fillers. Preliminary tests were conducted in order to determine the volume of usage as well as the concentrations (wt %) of S-PRG filler. Based on the results given these experiments, we compared the salivary fluoride concentrations following toothbrushing with 0.5 g of 4 different types of toothpastes: 5 wt % S-PRG filler, 1400 ppm F AmF (amine fluoride), 1500 ppm F NaF (sodium fluoride), and MFP (monofluorophosphate) containing toothpaste.

METHODS

Of the 12 participants, 7 participated in the preliminary study and 8 in the main study. All participants brushed their teeth using the scrubbing method for 2 min. At first, 1.0 and 0.5 g of 20 wt % S-PRG filler toothpastes were used to compare, then followed by 0.5 g of 0 (control), 1, and 5 wt % S-PRG toothpastes, respectively. The participants spat out once and rinsed with 15 mL of distilled water for 5 s. Saliva was collected for 3 min each at different time intervals of 0 (baseline), 5, 10, 15, 30, 60, 120, and 180 min after the rinsing. Fluoride concentrations were determined using a fluoride electrode, and the area under the salivary clearance - time curve (AUC: ppm‧min) of each toothpaste was calculated as the salivary fluoride retention. The main study was then conducted to evaluate the salivary fluoride concentrations as well as the AUC value using 0.5 g of 5 wt % S-PRG filler toothpaste, followed by NaF, MFP, and AmF toothpastes.

RESULTS

Since there were no statistical differences between using 1.0 and 0.5 g of 20 wt % S-PRG toothpastes in salivary fluoride concentrations as well as the AUC value throughout the 180 min measurement, the volume was set as 0.5 g for the following studies. Concentrations of 5 and 20 wt % S-PRG toothpastes retained 0.09 ppm F or more in saliva even after 180 min. No statistical differences were seen in the salivary fluoride concentrations at any time intervals as well as the AUC value between 5 and 20 wt % S-PRG toothpastes. Based on these results, the concentration of 5 wt % S-PRG toothpaste was used for the main comparative study. MFP toothpaste resulted in by far the lowest salivary fluoride concentrations (0.06 ppm F at 180 min) and the AUC value (24.6 ppm‧min), whereas 5 wt % S-PRG toothpaste (0.15 ppm F at 180 min, 92.3 ppm‧min) displayed retention on par with AmF toothpaste which appeared to result in higher values (0.17 ppm F at 180 min, 103 ppm‧min), compared to NaF toothpaste (0.12 ppm F at 180 min, 49.3 ppm‧min).

CONCLUSIONS

The salivary fluoride concentrations following toothbrushing with 0.5 g of 5 wt % S-PRG filler containing toothpaste showed retention similar to the best performing 1400 ppm F AmF toothpaste even 180 min after toothbrushing.

Fluoride Intake and Salivary Fluoride Retention after Using High-Fluoride Toothpaste Followed by Post-Brushing Water Rinsing and Conventional (1400-1450 ppm) Fluoride Toothpastes Used without Rinsing

This study aimed to compare the fluoride intake and salivary fluoride levels after brushing with conventional (1400-1450 ppm) fluoride toothpaste containing different fluoride agents: amine fluoride (AmF), sodium fluoride (NaF), sodium monofluorophosphate (SMFP), potassium fluoride (KF), and a high-fluoride (5000 ppm) toothpaste containing NaF. Fourteen volunteers took part in the study. They were instructed to brush and spit without rinsing after using conventional toothpaste or brush and rinse with water after using a high-fluoride toothpaste. Fluoride concentrations were determined using ion-selective fluoride (09-37 type) in the saliva samples before and after procedures. Fluoride intake was estimated based on fluoride recovered after brushing. Additionally, the amount of fluoride present in the oral fluids and lost during the rapid clearance phase after toothbrushing was calculated based on salivary fluoride levels and saliva flow immediately after brushing. Salivary fluoride after using high-fluoride toothpaste was significantly higher than those observed after conventional products. Two hours after brushing, salivary fluoride concentrations did not differ significantly from baseline values (p > 0.05) unless a high-fluoride product was used. Results indicate that by refraining from rinsing after brushing with conventional toothpaste, we cannot obtain fluoride retention in saliva as with high-fluoride toothpaste. Fluoride ingestion was higher after using a high-fluoride product.

Oral care product formulations, properties and challenges

This review explores the physical, chemical and structural properties of key components of oral care products, whilst looking at the challenges which need to be overcome to continue to improve the efficacy of oral care, and improve dental health. Oral care has been an essential part of all populations and cultures around the world for thousands of years. To maintain good oral health, dental plaque causing bacteria and malodour must be controlled whilst also strengthening and protecting the teeth to prevent dental caries. Advanced modern formulations need to provide controlled and extended release of ingredients vital for dental health. With modern day products such as toothpastes and mouthwashes, it has never been easier to maintain good oral hygiene and health, yet the incidence of dental caries is still on the rise. The complex formulations of modern toothpastes and mouthwashes makes them one of the most sophisticated pharmaceutical products on the market today. The demands of the consumer coupled with the complexity of the oral cavity make it one of the most challenging development processes.