Plaque Fluoride Concentrations Research Articles

Plaque Fluoride Levels as a Predictor of Caries Development in Early Childhood with High Sugar Exposure - A Preliminary Study.

ObjectiveThis longitudinal study aimed to investigate if the plaque fluoride (PF) concentration can predict the early childhood caries onset. Design: As part of a larger study, 188 preschoolers were clinically evaluated for early childhood caries diagnosis, at baseline and after 1-year follow-up. After that, the final sample comprised: 1. children who had already caries at baseline (decayed, missing or filled surfaces, as well as white chalky white spot lesions adjacent to gingival margins) and developed at least one more cavitation after one year (n=16), and 2. children who never had or developed any caries lesions, including active white spots lesions (n=15). Before the clinical examinations, dental plaque was collected. PF concentration was determined with an ion-specific electrode. A chart was used to estimate the mean daily sugar exposure. The results were statistically analyzed by Spearman correlation and logistic regression analyses (α=0.05).ResultsAfter one year, a positive significant correlation between caries development and liquid sucrose, total sugar and total sucrose consumption increments was found (p<0.05). Moreover, the solid sugar, solid sucrose and total sugar exposure at baseline were positively correlated with the presence of dental plaque at follow-up (p<0.05). To top it all, children with PF concentrations ≤0.1 μg/mg at baseline were 10 times more likely to develop caries.ConclusionIn conclusion, this study demonstrated for the first time in vivo that low PF concentration is a predictor of caries development in primary teeth.

Residents' journal review

Residents' journal review

The effect of toothbrushing and flossing sequence on interdental plaque reduction and fluoride retention: A randomized controlled clinical trial.

Mechanical plaque control methods such as brushing and flossing are highly recommended to remove dental plaque. The aim of this study is to evaluate the efficacy of the sequence of brushing and flossing on reducing interdental plaque and increasing fluoride retention in that area. This randomized controlled crossover trial was conducted on 25 dental students. After prophylaxis, they were asked to discontinue all forms of oral hygiene for 48hours. The study was performed in two phases with two-week washout intervals. In one phase, they first brushed, then flossed (sequence 1: brush-floss group). In the other phase they initially used dental floss then brushed (sequence 2: floss-brush group). At each phase, dental plaque (using the Rustogi Modified Navy Plaque Index) and fluoride concentrations (using a fluoride ion specific electrode) were measured before and after flossing and brushing, and the dental plaque reduction and fluoride increase were compared between the two groups using the mixed model test. A significance level of 5% was selected. In the floss-brush group interdental and whole plaque was reduced significantly more than the brush-floss group (p=0.001, p=0.009 respectively). However, marginal plaque did not show any statistically significant difference between the two groups (p=0.2). Fluoride concentrations in interdental plaque were significantly higher in the floss-brush group than the other group (p=0.027). The results showed that flossing followed by brushing is preferred to brushing then flossing in order to reduce interdental plaque and increase fluoride concentration in interdental plaque.

Anticaries Potential of a Sodium Monofluorophosphate Dentifrice Containing Calcium Sodium Phosphosilicate: Exploratory in situ Randomized Trial

Calcium sodium phosphosilicate (CSPS) is a bioactive glass material that alleviates dentin hypersensitivity and is postulated to confer remineralization of caries lesions. This single-centre, randomized, single (investigator)-blind, placebo-controlled, crossover, in situ study explored whether the addition of 5% CSPS to a nonaqueous fluoride (F) such as sodium monofluorophosphate (SMFP)-containing dentifrice affects its cariostatic ability. Seventy-seven subjects wore 4 gauze-covered enamel specimens with preformed lesions (2 surface-softened and 2 subsurface) placed buccally on their mandibular bilateral dentures for up to 4 weeks. Subjects brushed twice daily with 1 of the 5 study dentifrices: 927 ppm F/5% CSPS, 927 ppm F/0% CSPS, 250 ppm F/0% CSPS, 0 ppm F/5% CSPS, or 0 ppm F/0% CSPS. Specimens were retrieved after either 21 (surface-softened lesions; analyzed by Knoop surface microhardness [SMH]) or 28 days (subsurface lesions; analyzed by transverse microradiography). The enamel fluoride uptake was determined for all specimens using a microbiopsy technique. The concentrations of fluoride and calcium in gauze-retrieved plaque were also evaluated. Higher dentifrice fluoride concentrations led to greater remineralization and fluoridation of both lesion types and increased plaque fluoride concentrations. CSPS did not improve the cariostatic properties of SMFP; there were no statistically significant differences between 927 ppm F/5% CSPS and 927 ppm F/0% CSPS in percent SMH recovery (p = 0.6788), change in integrated mineral loss (p = 0.5908), or lesion depth (p = 0.6622). Likewise, 0 ppm F/5% CSPS did not provide any benefits in comparison to 0 ppm F/0% CSPS. In conclusion, CSPS does not negatively impact nor does it improve the ability of an SMFP dentifrice to affect remineralization of caries lesions.

High Fluoride Dentifrices for Elderly and Vulnerable Adults: Does It Work and if So, Then Why?

The primary aim of this work is to present the available evidence that toothpastes containing >1,500 ppm fluoride (2,500-2,800 and 5,000 ppm F) provide an additional caries preventive effect on root caries lesions in elderly patients compared to traditional dentifrices (1,000-1,450 ppm F). The secondary aim of this paper is to discuss why high fluoride dentifrices in general should perform better than traditional F-containing toothpaste. When examining the few studies that have considered the preventive benefits of high fluoride products on root caries the relative risk appears to be around 0.5, and the risk can thus be halved by exchanging traditional F-containing toothpaste for toothpaste containing 5,000 ppm F. There is reasonable evidence that high fluoride dentifrices significantly increase the fluoride concentration in saliva during the day and the fluoride concentration in plaque compared to traditional F toothpaste. Furthermore, the use of toothpaste with 5,000 ppm F significantly reduces the amount of plaque accumulated, decreases the number of mutans streptococci and lactobacilli and possibly promotes calcium fluoride deposits to a higher degree than after the use of traditional F-containing toothpaste.

Mode of drinking fluoridated milk: effect on intraoral fluoride concentrations

To determine the effect of the mode of drinking fluoridated milk on salivary and plaque fluoride concentrations. Fluoridated milk was ingested by 32 children in three ways: (a) directly from the container (1.0 and 5.0 mg F/litre), (b) through a straw with the tip between the lips (5.0 mg F/litre), and (c) with the tip deep in the oral cavity (5.0 mg F/litre). Saliva was collected at baseline and 2, 15, and 40 min and plaque at baseline and 20 min after drinking. Fluoride concentrations were determined using the electrode after HMDS-facilitated diffusion. The mode of drinking did not affect fluoride concentrations in saliva or plaque. The average 2-min salivary concentrations were 65 ng F/mL for the 1.0 mg F/litre group and 276 ng F/mL for the three 5.0 mg F/litre groups (P < 0.01). The average of the 15- and 40-min salivary concentrations was 22 ng F/mL for the 1.0 mg F/litre group and 41 ng F/mL for the 5.0 mg F/litre groups (P < 0.01). Plaque concentrations showed the same patterns as in saliva, that is, they were higher in the three 5.0 mg F/litre groups than in the 1.0 mg F/litre group and the differences among the 5.0 mg F/litre groups were not statistically significant. Salivary and plaque fluoride concentrations were independent of the mode of drinking but directly related to milk fluoride concentrations.

Intraoral fluoride levels after use of conventional and high-fluoride dentifrices.

This study aimed to evaluate saliva and plaque as indicators of intraoral fluoride (F) levels after the use of conventional and high-fluoride dentifrices. Subjects were randomly assigned to brush their teeth with conventional (1000ppmF), high-fluoride (5000ppmF), and placebo dentifrices (fluoride free) for 10days, following a double-blind, crossover protocol. Saliva and plaque samples were collected on the morning of the5(th) and 10th days, respectivelyat 1 and 12h after brushing, and analyzed with an ion-selective electrode after HMDS-facilitated diffusion. Data were analyzed by two-way repeated measures ANOVA, Tukey's test and Spearman's correlation coefficient (p < 0.05). Plaque and salivary F levels were significantly increased after the use of conventional and high-fluoride dentifrices when compared to values obtained for placebo, except plaque 12h after the use of conventional dentifrice. A positive and significant correlation was found between fluoride concentrations in plaque and saliva for both times of sample collection. Both indicators assessed were able to detect significant differences among treatments and between times after brushing. The use of a high-fluoride dentifrice is able to significantly increase intraoral fluoride levels throughout the day, being therefore a useful therapy for patients at high caries risk. A dentifrice with high fluoride concentrationcould be regarded as a useful therapy of F delivery for high caries-risk patients, since intraoral F levels were sustained throughout most of the day after using this formulation.

Efeito de Três Soluções Tópicas de Flúor no Nível de Flúor do Biofilme Dentário

Objective: To examine process inside plaque after application of three topical fluoride solutions: 1% TiF4, 1% NaF and Aminfluorid solution. Efficiency of three of these was estimated through concentrations of fluoride ions. Methods: Fluoride ions concentrations were measured and demonstrated as potential of fluoride electrode. 60 adult volunteers, divided in three groups (20 volunteers for each group, one agent per one group) have participated in the research. Subjects refrained of oral hygiene for 48 hours before the experiment. Plaque samples were taken before the application of fluoride solutions, and again after 5, 30, 60 and 120 minutes following the treatment. Results: Fluoride concentrations in plaque were not significantly different for three tested solutions. Conclusion: There isn’t clinically significant difference in efficacy of three used topical fluoride agents, despite their pH values differences. Only one statistically significant difference appeared after 60 minutes between sodium fluoride and titanium tetra fluoride, but it disappeared after 120 minutes.

Effects of Regular and Low-fluoride Dentifrices on Plaque Fluoride

Previous studies have indicated that the use of low-fluoride dentifrices could lead to proportionally higher plaque fluoride levels when compared with conventional dentifrices. This double-blind, randomized, crossover study determined the effects of placebo, low-fluoride, and conventional dentifrices on plaque fluoride concentrations ([F]) in children living in communities with 0.04, 0.72, and 3.36 ppm F in the drinking water. Children used the toothpastes twice daily, for 1 wk. Samples were collected 1 and 12 hrs after the last use of dentifrices and were analyzed for fluoride and calcium. Similar increases were found 1 hr after the children brushed with low-fluoride (ca. 1.9 mmol F/kg) and conventional (ca. 2.4 mmol F/kg) dentifrices in the 0.04- and 0.72-ppm-F communities. Despite the fact that the increases were less pronounced in the 3.36-ppm-F community, our results indicate that the use of a low-fluoride dentifrice promotes a proportionally higher increase in plaque [F] when compared with that achieved with a conventional dentifrice, based on dose-response considerations.

In vivo delivery of fluoride and calcium from toothpaste containing 2% hydroxyapatite

Objective: To measure the in vivo delivery of fluoride and calcium of a new oral health toothpaste containing zinc citrate trihydrate, hydroxyapatite, potassium citrate and α-tocopherol acetate (Vitamin E) compared to standard fluoride toothpaste. Methods: The new toothpaste contained 2% hydroxyapatite and 0.1% Vitamin E acetate (α-tocopherol acetate). It also included an anti-caries agent (1.1% sodium monofluorophosphate) an antigingivitis agent (2% zinc citrate trihydrate) and an anti-sensitivity agent (potassium cit-rate). Two studies were carried out. In study 1 the bio-availability of fluoride was measured in plaque after brushing with the test and a clinically tested fluoride toothpaste (control). In study 2 the effect of the test toothpaste on calcium levels in saliva and on the tooth surface was investigated compared to a toothpaste without added hydroxyapatite. Results: The fluoride concentration in plaque after brushing with the test and control toothpaste was significantly higher in both groups than before brushing (p<0.001). The difference in post-brushing fluoride concentration between the two groups was not statistically significant. The calcium concentration in saliva after brushing with the test toothpaste was higher than after brushing with the control toothpaste. The difference between the two means was statistically significant (p<0.001). Mean calcium concentration in tooth surface swab samples were significantly higher in the test group than in the control group (p<0.001). Conclusion: Plaque fluoride concentration was significantly increased after brushing with a new toothpaste containing 2% hydroxyapatite. The concentration of calcium in saliva and on the tooth surface was significantly increased compared to a standard toothpaste.

Fluoride Uptake by Plaque from Water and from Dentifrice

It has been suggested that fluoride retention in plaque is limited by available binding sites. We determined the effects of fluoridated or placebo dentifrices on plaque and salivary fluoride concentrations [F]s in communities with different water fluoride concentrations (0.04, 0.85, 3.5 ppm). After one week of dentifrice use, samples were collected 1.0 and 12 hrs after the last use of dentifrices. After the use of fluoridated dentifrice, plaque fluoride concentrations were higher at both times, except at 12 hrs in the 3.5-ppm community. Plaque concentrations at 1.0 hr after the use of fluoridated dentifrice increased almost constantly (6.5 mmol/kg), but then decreased approximately 50% at 12 hrs in each community. Unlike previous studies, the present findings suggest that the use of fluoridated dentifrice is likely to increase plaque fluoride concentrations significantly for up to 12 hrs in areas where the water contains fluoride close to 1.0 ppm. As previously reported, plaque fluoride concentrations were directly related to calcium concentrations.

Fluoride concentrations in dental plaque and saliva after the use of a fluoride dentifrice preceded by a calcium lactate rinse

Plaque fluoride concentrations ([F]) are directly related to plaque calcium concentrations [Ca]. Attempts to increase plaque F uptake from dentifrices or rinses have used methods designed to increase plaque [Ca] but with inconsistent results. This double-blind, double-crossover study tested the effect of a 150 mM calcium lactate rinse used prior to brushing with placebo or fluoridated dentifrices (1030 p.p.m. as NaF) on plaque and salivary [F] and [Ca]. Sixteen children (8-10 yr of age) were randomly assigned to four different groups according to the four treatments (placebo dentifrice or fluoridated dentifrice preceded by calcium lactate or deionized water prerinses). Plaque and saliva were collected 1 and 12 h after brushing on day 7 after starting to use the dentifrices. F was determined using the electrode and Ca was determined using atomic absorption spectrometry. Plaque and salivary [Ca] were not significantly increased after use of the calcium lactate prerinse, except for plaque [Ca] 1 h after the use of the placebo dentifrice. A significant increase in salivary [F] was associated with the calcium lactate prerinse only at 1 h after the use of the fluoridated dentifrice. The the calcium lactate prerinse did not significantly affect plaque [F] under any condition.

Buffering effect of a prophylactic gel on dental plaque

The aim of this study was to evaluate the effect of a new prophylactic gel on plaque pH and plaque fluoride concentration. Twelve participants with normal (n=6, >or=0.7 ml/min) and low (n=6, <0.7 ml/min) stimulated whole salivary secretion rate were included. After 3 days of plaque accumulation, at random the participants were (1) treated with Profylin fluoride gel with buffering components (active gel), (2) treated with Profylin fluoride gel without buffering components (placebo gel), (3) asked to rinse with water, and (4) given no treatment. All test series were followed by rinsing with a nutrition solution; after which registration of plaque pH was performed during 60 min. There were two drop outs with low salivary secretion rate in the water session. The overall least pronounced pH fall was found after the use of the prophylactic gel. Significant differences between the prophylactic gel and the placebo gel were found for the participants with normal secretion rate. Fluoride plaque concentrations evaluated in 12 individuals after (1) application of the active gel, (2) rinsing with 0.2% NaF, and (3) rinsing with water showed significantly higher values after rinsing with the NaF solution. It can be concluded that application of the active gel, particularly in subjects with normal salivary secretion rate, in general, buffered plaque pH to higher levels. Factors like concentration of buffering agent and solubility of the gel need to be further evaluated to improve the effect.

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.

Penetration of Fluoride into Natural Plaque Biofilms

Caries occurs at inaccessible stagnation sites where plaque removal is difficult. Here, the penetration through plaque of protective components, such as fluoride, is likely to be crucial in caries inhibition. We hypothesized that topically applied fluoride would readily penetrate such plaque deposits. In this study, plaque biofilms generated in vivo on natural enamel surfaces were exposed to NaF (1000 ppm F-) for 30 or 120 sec (equivalent to toothbrushing) or for 30 min. Biofilms were then sectioned throughout their depth, and the fluoride content of each section was determined with the use of a fluoride electrode. Exposure to NaF for 30 or 120 sec increased plaque fluoride concentrations near the saliva interface, while concentrations near the enamel surface remained low. Fluoride penetration increased with duration of NaF exposure. Removal of exogenous fluoride resulted in fluoride loss and redistribution. Penetration of fluoride into plaque biofilms during brief topical exposure is restricted, which may limit anti-caries efficacy.

Plaque Fluoride Concentrations in a Community without Water Fluoridation: Effects of Calcium and Use of a Fluoride or Placebo Dentifrice

The results of a recent study by Whitford et al. [Caries Res 2002;36:256–265] with subjects whose drinking water was fluoridated led to two major conclusions: (1) Compared to the use of a placebo dentifrice, plaque fluoride concentrations ([F]) throughout much of the day are not significantly increased by the use of an F dentifrice but (2) they are positively related to plaque [Ca] (p = 0.0001). The present double-blind, double-crossover study with 16 subjects used the same protocol and was done to: (1) determine the effects of the use of an F dentifrice on salivary and plaque [F] in a community without water fluoridation and (2) further examine the relationship between plaque [Ca] and [F]. Following the use of an F dentifrice or placebo for one week, whole saliva and plaque were collected 1.0 and 12 h after the last use of the products. The study was repeated to include rinsing with a 20 mmol/l CaCl₂ solution immediately before the use of the dentifrices. The CaCl₂ rinse had only minor effects on salivary [Ca] and [F] and none on the plaque concentrations. Unlike the results found in the fluoridated community, all salivary and plaque [F] associated with the use of the F dentifrice were significantly higher than those associated with the use of the placebo. The results suggest that the cariostatic effectiveness of an F dentifrice should be greater in areas without water fluoridation. As noted previously, plaque [F] were positively related to plaque [Ca] (p = 0.0001).

Fluoride Concentrations in Saliva and Dental Plaque in Young Children after Intake of Fluoridated Milk

This study determined fluoride (F) concentrations in whole saliva and dental plaque after intake of fluoridated milk using a randomised crossover experimental design. Eighteen healthy children (6–8 years) were subjected to each of four different 3-day drinking regimens: (a) 200 ml F-free tap water; (b) 200 ml tap water with 1.0 mg F; (c) 200 ml standard milk, and (d) 200 ml standard milk with 1.0 mg F. A washout period of 7 days was organised between the different drinking regimens. All children used F-free toothpaste prior to and during the trial and were instructed to avoid F-rich food and drinks. F concentration in unstimulated whole saliva was determined at baseline and after 15 and 120 min and in plaque samples at baseline and after 2 h. The mean baseline values ranged from 0.01 to 0.02 mg F/l in saliva and between 10.4 and 14.2 mg F/l in dental plaque. A statistically significant (p < 0.05) increase of F was disclosed in saliva 15 min after drinking F-containing milk and water (0.052 and 0.058 mg F/l, respectively). After 2 h, the salivary F^– concentrations were back to baseline values. In the plaque, however, a statistically significant (p < 0.01) twofold increase was found at 2 h after the intake of fluoridated milk and water, respectively. The results indicate that consumption of fluoridated milk contributes to a F storing process with significantly elevated F concentrations in dental plaque up to 2 h after intake. Further studies are required to determine the ‘therapeutic concentration’ of F in dental plaque after intake of fluoridated milk.

Fluoride concentration in supragingival dental plaque after a single intake or habitual consumption of fluoridated milk

The aim of this study was to evaluate the fluoride concentration in supragingival dental plaque after single and repeated intakes of fluoridated milk. The study group consisted of 22 schoolchildren, young adults and adults of both sexes, 8-41 years of age. After a 2-week fluoride depletion period and 3 days of plaque accumulation, 200 ml of fluoridated milk (1g F) was ingested along with a standardized lunch meal. Plaque samples were collected immediately before the intake and after 30, 120 and 240 min. From the adult participants (n = 9), additional samples were colleted after 12 and 18 h. After a fluoride-free washout period of at least 2 weeks, the whole experimental procedure was repeated after 4 consecutive daily intakes of fluoridated milk. The fluoride concentration was determined after micro-diffusion with a fluoride selective electrode. The results showed a statistically significant 3-fold increase of the plaque fluoride levels up to 4 h after the intake. At 12 and 18 h after the intake, the recorded levels went gradually back to baseline. There was no significant difference between the fluoride concentrations in the supragingival plaque after the single intake compared with the repeated intakes. In conclusion, the findings support the suggestion that milk is a suitable vehicle for local fluoride administration into the oral cavity, also when consumed together with a meal.

Dental plaque fluoride and pH in children exposed to different water fluoride levels

The aims of this study were to determine plaque fluoride concentrations in children not exposed to topical fluorides but to different fluoride levels in the drinking water (0.1 and 2.0 ppm), and to observe whether plaque fluoride was related to plaque pH. Twenty-five children (6 to 7 years old) were selected from two rural villages in Brazil. A sub-set of subjects was examined for resting and fermenting plaque pH before sampling. A maximum of 14 sites was studied in each subject (vestibular and interproximal of first molars and central incisors). Plaque fluoride was extracted and measured with an inverted fluoride electrode under oil. Amounts of plaque were determined by protein analysis. Mean values in the 0.1 ppm village were 1.3 ngF/mg of plaque wet weight (SD = 1.1) and in the 2.0 ppm village 2.5 ngF/mg (SD = 2.1) and were not statistically different (Kruskal-Wallis test, P = 0.09). Plaque fluoride varied considerably from site to site in the same mouth. Combining sites in all subjects, plaque fluoride concentrations were positively related to resting and fermenting pH (regression analysis, P < 0.01-0.001, adjR2 = 0.12-0.31). On an individual basis the same trend was found for fermenting, but not for resting pH. In conclusion, our findings showed a moderate influence of water fluoride upon dental plaque fluoride concentrations and give some support to the theory that low fermenting pH may contribute to the release of bound plaque fluoride.

Fluoride release and cariostatic ability of a compomer and a resin-modified glass ionomer cement used for orthodontic bonding

Objectives: The aims of this study were to compare the local and systemic uptake of fluoride released from a compomer material (Dyract Ortho) and a resin-modified glass ionomer cement (Vitremer) with that of a conventional resin adhesive (Right-On) and to compare the cariostatic ability of each of the test materials with that of the resin control. Methods: Twenty six patients were randomly allocated to have a bracket bonded to a premolar on one side of the arch with one of the test materials and on the opposite side with the control material. Premolars destined for extraction as part of an orthodontic treatment plan were selected for bonding. A non-fluoride toothpaste was used by all participants for 4 weeks prior to bracket bonding and throughout the 4 week trial period. Fluoride release was measured in saliva, plaque and urine samples taken pre-bonding and 4 weeks post-bonding. Enamel demineralisation was assessed by scoring the buccal surface of each extracted tooth using a caries index. Results: Neither Vitremer nor Dyract Ortho altered salivary or urinary fluoride concentration significantly 4 weeks post-bonding but plaque fluoride concentration increased significantly around premolars bonded with Vitremer. The test materials as a combined group were associated with significantly less demineralisation than the control material but there was no significant difference in cariostatic ability detected between either Dyract Ortho or Vitremer when each group was compared separately with the control. Conclusions: Fluoride released from Dyract Ortho or Vitremer is likely to exert a local and not a systemic effect. In a 4-week clinical study, the cariostatic ability of the fluoride-releasing cements, as a combined group, was superior to that of the non-fluoride releasing control but there was no significant difference in cariostatic ability between the two test materials when each test group was compared separately with the control.