Studies on plaque fluoride after use of F-containing dentifrices

Randomized investigation of the bioavailability of fluoride in saliva after administration of sodium fluoride, amine fluoride and fluoride containing bioactive glass dentifrices

OBJECTIVES

Bioactive glasses which degrade in aqueous solutions may release bioactive ions such as fluoride (F-) and support fluoride bioavailability in saliva. We investigated how these effects would be apparent in an in vivo experimental trial after toothbrushing in comparison with sodium fluoride and amine fluoride.

MATERIAL AND METHODS

In this single-center, randomized, parallel in vivo trial with a three strata block design, where healthy subjects were randomly assigned into three groups. Each group brushed their teeth either with fluoridated bioactive glass containing dentifrice, with a sodium fluoride (NaF) containing dentifrice or with amine fluoride (AmF) containing toothpaste. Saliva was collected time intervals before, immediately after, 30, 60 and 120 min after toothbrushing. Fluoride concentration was determined in supernatant saliva and salivary sediment using a fluoride ion selective electrode. The data were evaluated statistically using non-parametric tests.

RESULTS

The increase of bioactive fluoride in supernatant saliva was higher after application of NaF or AmF compared to fluoridated bioactive glass. In salivary sediment bioavailability of fluoride lasted longer after application of fluoridated bioactive glass.

CONCLUSIONS

Toothbrushing with the fluoride containing bioactive glass dentifrices had positive effects on the fluoride bioavailability within two hours. Fluoride containing bioactive glass represent a new area for investigation in caries prophylaxis. The bioactive potential impact on the tooth remineralization should be examined further.

TRIAL REGISTRATION

DRKS00016038 .

Fluoride Levels in Saliva and Plaque following the Use of High Fluoride and Conventional Dentifrices- a Triple Blinded Randomised Parallel Group Trial

Context

The comparison of fluoride levels in saliva and plaque following the use of conventional, 2800 and 5000 ppm dentifrices for different time intervals up to 24 hours has not been explored.

Aim

The aim of the present study was to assess salivary and plaque fluoride levels at different time intervals following the use of high fluoride dentifrices.

Study Design

This randomised control trial was conducted on sixty adolescents between the age group of 16 and 18 years divided into three groups A, B, and C.

Intervention

Subjects were asked to brush the occlusal surfaces of posterior teeth with one of the dentifrices for 2 min. Unstimulated whole saliva and plaque samples were collected at different time intervals. Fluoride levels were determined using SPADNS method. Data was collected and statistically analyzed using SPSS 20 Inc. by mixed repeated measure ANOVA.

Results

A significant difference in fluoride levels was observed at different time intervals in both saliva (p=0.048) and plaque (p=0.03). The variance was low with time and concentration of the dentifrice used in saliva, whereas the magnitude of treatment was large for time (>0.25) but small for (<0.09) concentration in plaque.

Conclusion

A significant difference in fluoride levels was observed at different time intervals in both saliva and plaque among the three groups. There was a positive correlation between fluoride levels in saliva and plaque. Both high fluoride dentifrices were effective in maintaining higher intraoral fluoride levels up to 12 hours and 5000 ppm up to 24 hours compared to conventional dentifrice.

Influence of Toothpaste pH on Its Capacity to Prevent Enamel Demineralization

Aim:

This study evaluated in vitro the remineralization capacity of commercial toothpastes with different fluoride (F) concentrations and their effectiveness when they are acidified.

Materials and Methods:

One hundred and twelve caries-free teeth were used to prepare enamel specimens, and the specimens were divided into 16 groups (n = 7). Baseline surface Vickers microhardness was measured for all the specimens and all the tested groups were subjected to the pH-cycling regime involved five demineralization challenges each day for 10 days, and surface Vickers microhardness was then measured. Once daily, specimens were exposed for 30 min after last demineralization challenge of the day to the slurry of each toothpaste containing 1450 ppm F, 1000 ppm F, 450 ppm F, and 0 ppm F. The slurry was in original pH or acidulated on 6.5, 6.0, or 5.5 pH. The difference among tested group was assessed by analysis of variance and Newman–Keuls test (P < 0.05).

Results:

The highest increase in microhardness was detected after treatment with toothpaste containing 1450 ppm fluoride (percentage of increase in microhardness was 6.20%), and the biggest loss was detected after treatment with toothpaste containing no fluoride (percentage of decrease was 6.82%), but there was no significant difference between tested groups.

Conclusions:

The highest increase in microhardness was detected after treatment with toothpaste containing more fluorides (1450 ppm F) regardless of the acidity.

A comparative assessment of fluoride concentration available in saliva using daily prescribed topical fluoride agents

Objective:

To assess the availability of fluoride concentration in saliva following the use of fluoride mouthrinse and dentifrice.

Materials and Methods:

The experiment was carried out in 7–15 year-old school children of Chandigarh (n = 90). The children were nonfluoride users. Baseline saliva samples were collected. The subjects were exposed to two test agents, i.e., fluoride mouthrinse (0.05%, 225 ppm F) and dentifrice (1000 ppm F) for 7 days and on the day 8, saliva samples were collected over a 20 hrs period. Wash out period of 3^1/2 months was there before the subjects were exposed to the second test agent. Fluoride in saliva was estimated using fluoride ion-specific electrode. Written informed consent was taken.

Statistical Analysis:

Kolmogorov–Smirnov test was applied to test the normality of the variables. Mann–Whitney U-test was used to compare the fluoride concentration available in saliva at respective time intervals subsequent to use of the two test agents.

Results:

Fluoride concentration was elevated in saliva compared to baseline for both the test agents. Fluoride mouthrinse (0.05% sodium fluoride [NaF]) and dentifrice (1000 ppm monofluorophosphate [MFP]) showed a biphasic clearance. Peak in saliva occurred at 15 mins postuse. Night-time use resulted in higher concentration of fluoride in saliva compared to baseline. There was statistically significantly higher fluoride concentration available in saliva for the dentifrice at 5 hrs, 10 hrs, and 20 hrs postuse (P < 0.05).

Conclusion:

Subsequent to the use of NaF (0.05%) daily mouthrinse and MFP dentifrice (1000 ppm) the fluoride concentration in saliva remained elevated to a level of 0.12 ppm for mouthrinse and 0.14 ppm for dentifrice compared to baseline (0.03 ppm) up to 20 hrs postuse. The therapeutic window though not yet established but suggested is 0.1–1 ppm for prevention of demineralization, indicating that daily use of fluoride mouthrinse and dentifrice provides fluoride concentration in saliva for the prevention of demineralization.

The effect of fluoride slow-releasing devices on fluoride in plaque biofilms and saliva: a randomised controlled trial

AIM

To investigate the effect of the fluoride sustained slow-releasing device (FSSRD) on F levels in unstimulated saliva and undisturbed plaque biofilms over 7 days. The investigation also aimed at studying the effect of patient age on fluoride (F) concentrations in dental plaque biofilms and unstimulated saliva while using the FSSRD.

STUDY DESIGN

This was a randomised control double blind cross-over study.

METHODS

Sixty-five participants between the ages of 6-35 years took part in this study. The mean age of all the participants was 19.22 years with 24 participants aged between 6-16 years (mean age=11.8 years) and 41 participants aged between 16-35 years (mean age=23.57 years). Plaque biofilms were collected using a modification of the plaque generating device (MPGD) [Robinson et al., 1997]. During the whole study period, including a 7 day washout period before the first leg, all participants were asked to use only non-fluoridated toothpaste and to avoid where possible high fluoride containing foods or drinks. Whenever possible, the FSSRD/placebo device (PD) was attached to the second permanent molar, while the MPGD was attached to the first permanent molars in the same upper dental quadrant. At the end of each leg of the study whole, mixed unstimulated saliva was collected from all participants and analysed for F concentration.

STATISTICS

Statistical analysis using paired sample t-test was used to compare the results of F level between test and control groups, while, Spearman's correlation coefficient was used to test the relationship between patient's age and plaque weight against F concentration in plaque and saliva.

RESULTS

There was no statistically significant difference in F concentration in plaque and saliva between the test and control groups when analysed using paired sample t-test (p>0.05). There was no correlation between patient's age and F concentration in dental plaque and saliva (p>0.05), in both the test and control groups.

CONCLUSIONS

Our data showed no effect of the FSSRD in raising F concentrations in dental plaque and unstimulated whole saliva after 7 days. Such levels may require longer periods to become established.

Modified fluoride toothpaste technique reduces caries in orthodontic patients: A longitudinal, randomized clinical trial

INTRODUCTION

The hypothesis of this study was that toothpaste slurry rinsing, combined with other simple postbrushing steps (the modified fluoride toothpaste technique [MFTT]), would reduce the number of decayed and filled tooth surfaces.

METHODS

The study population consisted of 100 orthodontic patients randomly divided into 2 groups, 51 in the test group (mean age, 16.2 +/- 4 years) and 49 in the control group (mean age, 16.9 +/- 4 years). Each patient was examined before starting orthodontic treatment (baseline) and shortly after debonding (follow-up) in a 2-year study period. At each of these 2 visits, the patients were examined in the following order: interviewed by using a standardized questionnaire, plaque index registration, intraoral clinical examination, and radiographic examination (bitewings). The test group patients were instructed to use the MFTT. The control group patients were given the same fluoridated toothpaste as the test group and the routine clinical oral hygiene instructions.

RESULTS

Compared with the control group, the test group had significantly better plaque index scores at the end of the study. At follow-up, the clinical (P <0.001), radiographic (P <0.001), and clinical plus radiographic (P <0.001) incidences of decayed and filled surfaces were significantly reduced: 87%, 78%, and 83%, respectively, in the test group compared with the control group.

CONCLUSIONS

Compared with routine oral hygiene instructions with fluoride toothpaste, the use of the MFTT significantly reduced the incidence of new carious lesions in orthodontic patients. We believe that this simple regimen should be considered in orthodontic clinics.

Increased Salivary Fluoride Concentrations after Post-Brush Fluoride Rinsing Not Reflected in Dental Plaque

The aim of the present study was to assess fluoride concentrations in unstimulated saliva and buccal dental plaque 6 h after an oral hygiene procedure that consisted of brushing with an AmF/SnF2 dentifrice and different post-brush rinsing protocols: expectorating the excess of dentifrice foam and rinsing with tap water, expectorating only, or rinsing with 10 ml AmF/SnF2 mouthwash. The fluoride concentrations in plaque and saliva were increased after all three experimental protocols compared to F-free periods. The increase of the fluoride concentration in saliva was more pronounced after AmF/SnF2 mouthrinse as compared to rinsing with water and expectorating the excess of dentifrice foam. Such an effect was not seen in dental plaque. It is concluded that the potentially beneficial effect of not rinsing or fluoride rinsing after tooth brushing is not reflected in an increased fluoride concentration in newly formed dental plaque 6 h after brushing.

The biochemistry and physiology of metallic fluoride: action, mechanism, and implications

Fluoride is a well-known G protein activator. Activation of heterotrimeric GTP-binding proteins by fluoride requires trace amounts of Al3+ or Be2+ ions. AlFx mimics a gamma-phosphate at its transition state in a Galpha protein and is therefore able to inhibit its GTPase activity. AlFx also forms complexes with small GTP-binding proteins in the presence of their GTPase-activating proteins (GAP). As phosphate analogs, AlFx or BeFx affect the activity of a variety of phosphoryl transfer enzymes. Most of these enzymes are fundamentally important in cell signal transduction or energy metabolism. Al3+ and F- tend to form stable complexes in aqueous solution. The exact structure and concentration of AlFx depend on the pH and the amount of F- and Al3+ in the solution. Humans are exposed to both F and Al. It is possible that Al-F complexes may be formed in vivo, or formed in vitro prior to their intake by humans. Al-F complexes may play physiological or pathological roles in bone biology, fluorosis, neurotoxicity, and oral diseases such as dental caries and periodontal disease. The aim of this review is to discuss the basic chemical, biochemical, and toxicological properties of metallic fluoride, to explore its potential physiological and clinical implications.

Oral health in the United States: the post-fluoride generation

Tremendous strides have been made in reducing the incidence of tooth decay, periodontal diseases, and associated loss of teeth in adults and children since the inception of community water fluoridation programs. Yet the disadvantaged and poor have not fully shared in the benefits. Other challenges to oral health remain. Oral cancer and related smoking and smokeless tobacco use remain major public health problems. Access to preventive and therapeutic dental care is far from universal. Public health programs similar in commitment to the approach of community water fluoridation programs initiated in the 1950s and 1960s are needed to address neglected oral health needs of underserved and high-risk populations in the United States.

The application of in vitro models to research on demineralization and remineralization of the teeth

Progress in in vivo and in situ experimentation has led many researchers to speculate as to the relevance and importance of in vitro testing protocols in caries research. A Medline/Biosis search for the present review revealed well over 300 citations (since 1989) documenting in vitro tests associated with caries research on mineralization and fluoride reactivity. The present survey documents these recent applications of in vitro test methods in both mechanistic and 'profile' caries research. In mechanistic studies, in vitro protocols over the past five years have made possible detailed studies of dynamics occurring in mineral loss and gain from dental tissues and the reaction dynamics associated with fluoride anticaries activity. Similarly, in profile applications, in vitro protocols make possible the inexpensive and rapid--yet sensitive--assessment of F anticaries efficacy within fluoride-active systems, and these tests represent a key component of product activity confirmation. The ability to carry out single variable experiments under highly controlled conditions remains a key advantage in in vitro experimentation, and will likely drive even further utilization, as advances continue in physical-chemical and analytical techniques for substrate analysis in these protocols. Despite their advantages in vitro testing protocols have significant limitations, most particularly related to their inability to simulate the complex biological processes involved in caries.

Effect of low levels of fluoride on calcium uptake by demineralized human enamel

The effect of fluoride (ca. 0.1 parts/10(6)) on calcium uptake by enamel was examined under alternating remineralizing and demineralizing conditions. The remineralizing solutions contained either 0, 0.058, 0.104, or 0.138 parts/10(6) fluoride (ex NaF), while the demineralizing solutions contained no added fluoride. During the demineralization periods, calcium loss was similar for all groups. However, during the remineralizing periods, all levels of added fluoride were found to promote calcium uptake. Calcium levels taken up by the artificial lesions were sound to increase with increasing fluoride concentration in solution, and were independent of surface area of exposed enamel. In the absence of fluoride, even under conditions that are considered to be remineralizing, further demineralization took place.