Efficacy of an occluding toothpaste on dentinal hypersensitivity over 14 days.

OBJECTIVES: To evaluate a 0.454% stannous fluoride/5% sodium tripolyphosphate (STP) toothpaste's ability to provide relief from dentinal hypersensitivity (DH) applied using 'focused brushing.' MATERIALS AND METHODS: In two randomised, examiner-blind, parallel-group studies, a SnF2/STP toothpaste was applied by brushing two selected sensitive teeth before 1 min whole-mouth brushing, compared to 1 min whole-mouth brushing only, with a negative control toothpaste. DH was assessed via evaporative (air) (Schiff scale) and tactile (Yeaple probe) stimuli after 7 and 14 d of twice-daily brushing. RESULTS: In total, 141 (Study 1)/142 (Study 2) participants were randomised. In Study 1, the test treatment significantly reduced DH at 7/14 d versus baseline (7/14 d Schiff difference: -0.74 [-0.84,-0.65]/-1.39 [-1.54,-1.23]; tactile: 6.00 [4.88,7.13]/15.30 [13.34,17.26]); whereas the Control treatment did not (7/14 d Schiff difference -0.03 [-0.13,0.06]/-0.10 [-0.25,0.06]; tactile: 0.77 [-0.36,1.90]/0.77 [-1.20,2.74]). Differences between Test and Control were statistically significant (p < 0.0001 all cases). In Study 2, both treatments reduced DH compared to baseline by both measures, but there were no significant between-treatment differences. Toothpastes were generally well-tolerated. DISCUSSION AND CONCLUSIONS: Previous studies and Study 1 support SnF2/5% STP toothpaste efficacy; Study 2 results may have been influenced by placebo/Hawthorne effects. DH study design needs to, where possible, negate such effects.

Efficacy of an Experimental Occlusion Technology Toothpaste in the Relief of Dentinal Hypersensitivity: An 8-week Randomised Controlled Trial.

PURPOSE: A novel anhydrous toothpaste formulation has been developed containing the anti-dentinal hypersensitivity (DH) ingredient stannous fluoride (SnF2). MATERIALS AND METHODS: This randomised, controlled, examiner-blind, parallel-group, stratified (by baseline Schiff sensitivity score) study compared efficacy of an experimental 'Test' toothpaste (n = 67) containing 0.454% SnF2, 0.072% sodium fluoride and 5% sodium tripolyphosphate (all percentages w/w) with a negative 'Control' 0.76% sodium monofluorophosphate toothpaste (n = 68) in relieving DH in healthy Chinese adults. After 4-6 weeks acclimatisation, DH was assessed at baseline and following 4 and 8 weeks' twice-daily brushing by response to evaporative (air) (Schiff sensitivity score) and tactile (Yeaple probe) stimuli. An analysis of covariance model was used (factor: treatment group; covariate: baseline Schiff sensitivity score). RESULTS: Both Test and Control toothpastes statistically significantly reduced Schiff sensitivity score from baseline after 8 weeks' use; the Test toothpaste also statistically significantly reduced the score after 4 weeks' use (all p < 0.001). The Test toothpaste reduction was statistically significantly superior to the Control toothpaste reduction at both timepoints (p < 0.001). Percentage differences in treatment effects between Test and Control groups were 24.1% at 4 weeks and 31.7% at 8 weeks. Tactile threshold scores for both treatments statistically significantly increased from baseline at both timepoints (all p < 0.001); however, there were no statistically significant differences between Test and Control groups. Both toothpastes were well-tolerated with no adverse events reported. CONCLUSION: The Test toothpaste containing 0.454% SnF2 reduced DH statistically significantly more than the Control as evaluated by the Schiff sensitivity score, but not by tactile threshold.

In situ efficacy of an experimental toothpaste on enamel rehardening and prevention of demineralisation: a randomised, controlled trial.

BACKGROUND: A novel sodium fluoride toothpaste containing lactate ion and polyvinylmethylether-maleic anhydride has been developed to promote enamel remineralisation and resistance to demineralisation. In this in situ study, we compared this toothpaste ('Test') with a stannous fluoride-zinc citrate (SnF2-Zn) toothpaste ('Reference') (both 1100-1150 ppm fluoride) and a fluoride-free toothpaste ('Placebo') using an enamel dental erosion-rehardening model. METHODS: In each phase of this randomised, investigator-blind, crossover study, participants wore palatal appliances holding bovine enamel specimens with erosive lesions. They brushed their natural teeth with either the Test, Reference or Placebo toothpastes, then swished the resultant slurry. Specimens were removed at 2 h and 4 h post-brushing and exposed to an in vitro acid challenge. Surface microhardness was measured at each stage; enamel fluoride uptake was measured after in situ rehardening. Surface microhardness recovery, relative erosion resistance, enamel fluoride uptake and acid resistance ratio were calculated at both timepoints. RESULTS: Sixty two randomised participants completed the study. Test toothpaste treatment yielded significantly greater surface microhardness recovery, relative erosion resistance and enamel fluoride uptake values than either Reference or Placebo toothpastes after 2 and 4 h. The acid resistance ratio value for Test toothpaste was significantly greater than either of the other treatments after 2 h; after 4 h, it was significantly greater versus Placebo only. No treatment-related adverse events were reported. CONCLUSIONS: In this in situ model, the novel-formulation sodium fluoride toothpaste enhanced enamel rehardening and overall protection against demineralisation compared with a fluoride-free toothpaste and a marketed SnF2-Zn toothpaste. TRIAL REGISTRATION: ClinicalTrials.gov; NCT03296072; registered September 28, 2017.

Three randomized studies of dentine hypersensitivity reduction after short-term SnF2 toothpaste use.

AIM: To evaluate effects of a 0.454% stannous fluoride test toothpaste on dentine hypersensitivity (DH) applied by fingertip, then 3 days' brushing, versus a sodium monofluorophosphate-based control. MATERIALS AND METHODS: In three randomized clinical studies, DH was assessed using evaporative (Schiff scale) and tactile (Yeaple probe) stimuli. Participants applied toothpaste to two sensitive teeth by fingertip (60 s each); DH was re-assessed, prior to brushing. Test treatment participants brushed their sensitive teeth, with all participants then brushing all teeth for ≥60 s, twice daily for 3 days. DH was re-assessed. Data were analysed by study and then pooled. RESULTS: In two studies, test treatment significantly reduced DH versus control treatment after fingertip application and 3 days' brushing (both measures). In one study, both treatments significantly reduced DH without between-treatment differences. Mean Schiff differences (95% confidence intervals) for fingertip/3d were as follows: Study 1: -0.09 (-0.280, 0.092)/ -0.18 (-0.442, 0.072); Study 2: -0.72 (-0.839, -0.610)/ -1.02 (-1.150, -0.882); and Study 3: -0.26 (-0.387, -0.123)/ -0.92 (-1.055, -0.793). Pooled analysis indicated test treatment significantly reduced DH versus control (both timepoints, both measures). Toothpastes were generally well-tolerated. CONCLUSION: Studies indicated that single, fingertip application of a SnF2 toothpaste reduced DH versus a control. DH relief increased over 3 days.

Randomised clinical studies investigating immediate and short-term efficacy of an occluding toothpaste in providing dentine hypersensitivity relief.

BACKGROUND: Dentine hypersensitivity (DH) can occur after gum recession or enamel loss and may impact quality of life. Treatments include toothpastes that decrease DH by occluding dentine tubules. One effective occluding ingredient used in toothpastes is stannous fluoride (SnF2), but this can be unstable in aqueous formulation. These three studies aimed to characterise the short-term effects of an experimental, anhydrous SnF2 dentifrice on DH. METHODS: Three examiner-blind, parallel-group studies evaluated DH in participants with the condition after a single brushing and after 3d brushing with an experimental anhydrous 0.454% SnF2/polyphosphate toothpaste (Test) or a toothpaste containing 0.76% sodium monofluorophosphate (Control). Test treatment participants brushed two pre-identified sensitive teeth first, then their remaining dentition for ≥1 min ('focused brushing'). Control treatment participants brushed their whole dentition for ≥1 min. DH was measured after single brushing and after 3d twice-daily use, via evaporative (air) (Schiff Sensitivity Scale) and tactile (Yeaple probe) stimuli and analysed using an ANCOVA model. RESULTS: In all studies, after 3d treatment, the Test toothpaste/brushing regimen significantly reduced DH compared to the Control regimen by both evaporative and tactile stimuli assessment (p < 0.0001 for all). The Test regimen also significantly reduced DH from baseline at both time-points by both measures in all studies (p < 0.0001 for all). Mean Schiff sensitivity score differences (95% confidence intervals) between Test and Control regimens after 3d were: Study 1: - 0.45 (- 0.577, - 0.319); Study 2: - 0.40 (- 0.505, - 0.300); Study 3: - 1.31 (- 1.500, - 1.128). Mean tactile score differences were: Study 1: 11.30 (7.927, 14.662); Study 2: 3.57 (2.531, 4.614); Study 3: 24.54 (20.349, 28.736). After single use, in Studies 2 and 3, the Test toothpaste/brushing regimen significantly reduced DH versus Control by both measures (p < 0.001 for all); in Study 1, treatment differences were not significant. Toothpastes were generally well-tolerated. CONCLUSIONS: Taken together, these studies indicated focused brushing with an experimental anhydrous 0.454% SnF2/polyphosphate toothpaste reduces DH compared to brushing with a conventional toothpaste after single use, with greater reduction after 3d. TRIAL REGISTRATION: Registrations at ClinicalTrials.gov : Study 1: NCT02832375 (registered 26.July.2016); Study 2: NCT02731833 (registered 26.April.2016); Study 3: NCT02923895 (registered 5.October.2016).

Assessment of tubule occlusion properties of an experimental stannous fluoride toothpaste: A randomised clinical in situ study.

OBJECTIVES: To evaluate the ability of a modified in situ model to differentiate dentinal tubule occlusion properties of toothpaste formulations over 10 days of treatment. METHODS: This was a single-centre, three-treatment period, crossover, randomised, single-blind study with healthy participants wearing two lower oral appliances, each retaining four dentine samples, for 10 treatment days during each period of the study. Samples were power-brushed ex vivo twice on each treatment day with a Test toothpaste containing 0.454% stannous fluoride, a Control fluoride toothpaste containing 0.76% sodium monofluorophosphate, or mineral water. Dentine samples were subjected to in situ acid challenge (orange juice) on Days 9 and 10. Scanning electron microscopy images obtained at baseline and after 1, 4, 8 and 10 days of treatment were graded for degree of surface coverage by four calibrated examiners; the primary study endpoint was Day 8. RESULTS: After 4, but not 8, days' treatment, the degree of tubule occlusion increased in the dentine samples treated with the Test or Control toothpastes compared with the water-treated samples (p < 0.01 and p < 0.05, respectively). Following the acid challenge (Day 10), there was a statistically significantly greater degree of occlusion in the Test toothpaste-treated dentine samples compared with those treated with water (p < 0.01). No other comparisons were statistically significant. All study treatments were generally well-tolerated. CONCLUSIONS: This modified in situ model was unable to demonstrate statistically significant between-treatment differences in dentinal tubule occlusion after 8 days. Conversely, there are recognised developments that could be made to better identify product differences. Clinicaltrials.gov: NCT02768194. CLINICAL SIGNIFICANCE: Dentine hypersensitivity can be managed through brushing with stannous fluoride toothpastes, which occlude patent dentine tubules. Clinical studies measure pain but in situ models are needed to demonstrate occlusion intra-orally. However, this study did not demonstrate superior occlusion with stannous toothpaste; further methodological development is required to investigate its mode of action.

In situ anticaries efficacy of dentifrices with different formulations - A pooled analysis of results from three randomized clinical trials.

OBJECTIVES: Data generated from three similar in situ caries crossover studies presented the opportunity to conduct a pooled analysis to investigate how dentifrice formulations with different fluoride salts and combinations at concentrations of 1400-1450 ppm F, different abrasive systems and in some cases, carbomer (Carb), affect enamel caries lesion remineralization and fluoridation. METHODS: Subjects continuously wore modified partial dentures holding two gauze-covered partially-demineralized human enamel specimens for 14 days and brushed 2×/day with their assigned dentifrice: Study 1: sodium fluoride (NaF)/Carb/silica, NaF/silica, NaF + monofluorophosphate (MFP)/chalk; Study 2: NaF/Carb/silica, NaF + MFP/dical, amine fluoride (AmF)/silica; Study 3: NaF/Carb/silica, NaF + stannous fluoride (SnF2)/silica/hexametaphosphate (HMP). All studies included Placebo (0 ppm F) and/or dose-response controls (675 ppm F as NaF [675F-NaF]) ±Carb. Specimens were evaluated for percentage surface microhardness recovery (SMHR) and enamel fluoride uptake (EFU). RESULTS: All 1400-1450 ppm F dentifrices except NaF + SnF2/silica/HMP provided significantly greater lesion remineralization than Placebo (p < 0.0001): differences in SMHR ranged from 17.46% (NaF + MFP/dical) to 26.66% (AmF/silica). For EFU (back-transformed log EFU), all 1400-1450 ppm F dentifrices gave significant fluoride uptake compared to Placebo (p < 0.0001): increases in EFU ranged from 4.95 µg F/cm2 (NaF + SnF2/silica/HMP) to 16.32 µg F/cm2 (NaF/carb/silica). Dentifrices containing NaF or AmF as sole fluoride source provided the greatest remineralization and fluoridation; Carb addition did not alter fluoride efficacy; some excipients appeared to interfere with the cariostatic action of fluoride. Treatments were generally well-tolerated with ≤4 treatment-related adverse events per study. CONCLUSION: Commercially available fluoride dentifrices varied greatly in their ability to remineralize and fluoridate early caries lesions. CLINICAL SIGNIFICANCE: Fluoride dentifrices are the most impactful anticaries modality worldwide. While clinical caries trials have not consistently shown the superiority of one formulation over another, these findings using a sensitive in situ caries model indicated that dentifrices containing NaF or AmF as the sole fluoride source provided the greatest remineralization and fluoridation benefits.

Effect of phytate and zinc ions on fluoride toothpaste efficacy using an in situ caries model.

OBJECTIVES: To compare and explore the dose-response of phytate-containing 1150 ppm fluoride toothpastes on model caries lesions and to determine the impact of zinc ions. METHODS: This was a single-centre, randomised, blinded (examiner/laboratory analyst), six-treatment, four-period crossover, in situ study in adults with a removable bilateral maxillary partial denture. Study treatments were toothpastes containing: 0.425% phytate/F; 0.85% phytate/F; 0.85% phytate/Zn/F; F-only; Zn/F and a 0% F placebo. Where present, F was 1150 ppm as NaF; Zn was 0.3% as ZnCl2. Human enamel specimens containing early-stage, surface-softened (A-lesions) or more advanced, subsurface (B-lesions) caries lesions were placed into the buccal flanges of participants' modified partial denture (one of each lesion type per side). A-lesions were removed after 14 days of twice-daily treatment use; B-lesions were removed after a further 14 days. A-lesions were analysed for surface microhardness recovery. Both lesion types were analysed by transverse microradiography and for enamel fluoride uptake, with B-lesions additionally analysed by quantitative light-induced fluorescence. Comparison was carried out using an analysis of covariance model. RESULTS: Statistically significant differences between 1150 ppm F and the placebo toothpastes (p < 0.05) were shown for all measures, validating the model. No differences between fluoride toothpastes were observed for any measure with little evidence of a dose-response for phytate. Study treatments were generally well-tolerated. CONCLUSIONS: Results suggest phytate has little impact on fluoride's ability to promote early-stage lesion remineralisation or prevent more advanced lesion demineralisation in this in situ caries model. Similarly, results suggest zinc ions do not impair fluoride efficacy. CLINICAL SIGNIFICANCE: Toothpastes may contain therapeutic or cosmetic agents that could interfere with fluoride's caries prevention efficacy. The present in situ caries study has demonstrated that phytate, added to provide enhanced extrinsic stain removal/prevention, and zinc, added to inhibit malodour, do not impair fluoride efficacy.

A randomized clinical trial to evaluate the stain removal efficacy of a sodium phytate dentifrice formulation.

OBJECTIVES: Phytate is an organic, cyclic polyphosphate analogous to linear condensed polyphosphates used as stain removal agents. This study investigated stain removal efficacy of an experimental sodium phytate-containing dentifrice compared to a reference dentifrice. METHODS: An experimental, moderate abrasivity (relative dentine abrasivity [RDA] âˆ¼130) antisensitivity fluoride dentifrice containing sodium phytate (0.85% w/w as the hexasodium salt) (n = 111) was compared to a reference, marketed, low-abrasivity (RDA âˆ¼ 43), anti-sensitivity fluoride dentifrice (n = 113), both containing 1150 ppm fluoride as sodium fluoride. Primary efficacy variables were between-treatment differences in extrinsic dental stain of anterior teeth after 6 and 12 weeks' twice-daily use, using Lobene stain index (MacPherson modification, MLSI) mean area (A) and intensity (I) scores. Comparisons included whole-tooth and hard-to-reach areas (gingival, interproximal, body of lingual). RESULTS: At both 6- and 12-week timepoints, MLSI (A × I) scores for total area and hard-to-reach areas for the experimental dentifrice were statistically significantly lower than baseline (P < .0001 for all). This was demonstrated for the reference dentifrice at 6 weeks only, for total, interproximal (P < .0001 for both), and body of lingual (P = .0395) scores. Compared with the reference, the experimental dentifrice had statistically significantly lower MLSI scores at both 6 and 12 weeks for all outcome variables including both total MLSI (A × I) and hard-to reach areas (P < .0001 in all cases). Products were generally well-tolerated. CONCLUSIONS: Differences between treatments were considered clinically differentiable. Sodium phytate may therefore be a suitable additive ingredient to improve tooth stain control performance within an otherwise conventional dentifrice formulation. CLINICAL SIGNIFICANCE: Following 6 and 12 weeks brushing, clinically differentiable differences were shown in stain index scores with an experimental dentifrice containing sodium phytate compared to a reference dentifrice without sodium phytate. Sodium phytate may therefore be a suitable additive ingredient to improve tooth stain control performance within an otherwise conventional dentifrice formulation.

Effects of a sodium fluoride- and phytate-containing dentifrice on remineralisation of enamel erosive lesions-an in situ randomised clinical study.

OBJECTIVE: The objective of this work was to evaluate effects of a dentifrice containing sodium fluoride (1150 ppm F) and the organic polyphosphate phytate (0.85% w/w of the hexa-sodium salt) on in situ remineralisation of early enamel erosive lesions and resistance to subsequent demineralisation. MATERIALS AND METHODS: Subjects (n = 62) wore palatal appliances holding eight bovine enamel specimens with pre-formed erosive lesions. They brushed their natural teeth with the phytate test dentifrice (TD); a positive control dentifrice (PC, 1150 ppm fluoride as NaF); a reference dentifrice (RD, disodium pyrophosphate + 1100 ppm fluoride as NaF) or a negative control dentifrice (NC, fluoride-free) in a randomised, double-blind, crossover design. Specimens were removed at 2, 4 and 8 h post-brushing and exposed to an ex vivo acid challenge. Surface microhardness (Knoop) was measured at each stage. The primary efficacy variable was relative erosion resistance (RER); other variables included the surface microhardness recovery (SMHR), acid resistance ratio (ARR) and enamel fluoride uptake (EFU). RESULTS: After 4 h, the results for RER, ARR and EFU were in the order PC > TD = RD > NC with PC > TD = RD = NC for SMHR. Results at 2 and 8 h were generally consistent with the 4 h data. Mineralisation progressed over time. Dentifrices were generally well-tolerated. CONCLUSIONS: In this in situ model, addition of phytate or pyrophosphate to a fluoride dentifrice inhibited the remineralising effect of fluoride. Both formulations still delivered fluoride to the enamel and inhibited demineralisation, albeit to a lesser extent than a polyphosphate-free dentifrice. CLINICAL RELEVANCE: Addition of phytate or pyrophosphate to a fluoride dentifrice may reduce its net anti-erosive properties.

A Randomized in situ Clinical Study of Fluoride Dentifrices on Enamel Remineralization and Resistance to Demineralization: Effects of Zinc.

This study aimed to determine the effect of zinc ions and F concentration in a dentifrice on remineralization of early caries lesions in situ and on resistance to subsequent demineralization. This was a single-center, 6-period, 6-product, blinded (examiner, subject, analyst), randomized (n = 62), crossover study. Products (all NaF) were: 0, 250, 1,150 and 1,426 ppm F (dose-response controls), "Zn-A" (0.3% ZnCl2, 1,426 ppm F), and "Zn-B" (as Zn-A, with high-foaming surfactants) in a conventional silica base. Subjects wore palatal appliances holding partially demineralized bovine enamel specimens. They brushed their teeth with 1.5 g test dentifrice (25 s), then swished the slurry ensuring even exposure of specimens (95 s), expectorated, and rinsed (15 mL water, 10 s). After 4 h intraoral remineralization, specimens were removed and acid-challenged in vitro. Surface microhardness (SMH), measured pre-experimental, post-initial acid exposure, post-remineralization, and post-second acid exposure, was used to calculate recovery (SMHR), net acid resistance (NAR), and a new, specifically demineralization-focused calculation, "comparative acid resistance" (CAR). Enamel fluoride uptake (EFU) was also measured. For the F dose-response controls, all measures showed significant relationships with dentifrice F concentration (p < 0.0001). The presence of zinc counteracted the ability of F to promote remineralization in this model. Compared to the 1,426 ppm F control, the zinc formulations gave reduced SMHR, EFU, and NAR (all p < 0.0001); however, they showed evidence of increased CAR (Zn-A: p = 0.0040; Zn-B: p = 0.0846). Products were generally well tolerated. In this study, increasing dentifrice F concentration progressively increased in situ remineralization and demineralization resistance of early caries enamel lesions. Zinc ions reduced remineralization but could increase demineralization resistance.

A Randomized Clinical Study to Evaluate the Effect of Two Experimental Toothpastes on Tooth Enamel Gloss and Smoothness.

OBJECTIVES: The study compared the effects on examiner-assessed tooth gloss and smoothness of two experimental toothpastes (1% or 2% alumina abrasive) with a reference, silica-based toothpaste used twice daily for one, four, and eight weeks. The study also monitored the safety of the products. METHODS: This was a randomized, examiner-blind study, stratified by gloss score and age, three-treatment, parallel-group using healthy adult volunteers. Following a two-week washout period where subjects brushed with a conventional silica-abrasive toothpaste, 169 subjects began the trial period after receiving a dental scaling and polishing using the washout toothpaste. Subjects brushed for two minutes, twice daily, with their assigned toothpaste. The experimental toothpastes contained 927 ppm fluoride as NaF with either 1% or 2% alumina as the sole abrasive. The reference toothpaste contained 927 ppm fluoride as NaF in a conventional amorphous silica abrasive base. Enamel polish (i.e., gloss) was assessed visually by comparing the facial surfaces of the maxillary incisors with a set of standards. Tooth smoothness was assessed by lightly dragging a dental explorer over the surface. RESULTS: Subjects using the 2% alumina toothpaste had significantly higher gloss compared to the reference toothpaste at Weeks 1 and 4, but the difference was of borderline significance at Week 8 (one-covariate analysis: p = 0.0529; two-covariate analysis: p = 0.0494). Subjects using the 1% alumina toothpaste had significantly higher gloss improvement scores than the reference toothpaste at Weeks 4 and 8, but not at Week 1. All three treatment groups' gloss scores improved during the study. Regarding tooth smoothness, the effects of the experimental toothpastes followed a broadly similar profile to the effects on tooth gloss. After four weeks' use, both experimental toothpastes were superior to the reference. After eight weeks' use, however, only the 2% alumina toothpaste approached significant superiority versus the reference (p = 0.0639). CONCLUSIONS: The 1% and 2% alumina toothpastes improved tooth gloss compared to a standard silica toothpaste when used twice daily for two minutes over an eight-week study period. Furthermore, there was evidence of a corresponding increase in tooth smoothness.

The effect of dentifrice quantity and toothbrushing behaviour on oral delivery and retention of fluoride in vivo.

While toothpaste F(-) concentration and rinsing regimen have well-characterised impacts on fluoride's effectiveness, other aspects of brushing regimen have much less well-established effects, in particular, dentifrice quantity and brushing duration. An in vivo study (n = 42) of oral fluoride delivery (i.e. oral disposition post-brushing), and retention (i.e. concentration of F(-) in saliva post-brushing, a known efficacy predictor), was performed to compare effects observed with those of dentifrice F(-) concentration and rinsing regimen. Subjects brushed with a NaF-silica dentifrice (Aquafresh Advanced, 1,150 ppm F(-) ) or a control dentifrice (250 ppm F(-) , same base), for 45, 60, 120 or 180 seconds with 0.5 or 1.5 g dentifrice, and rinsed with 15 ml water once or three times in a cross-over design. The F(-) concentration was measured in post-brushing expectorate, rinse and toothbrush washing samples, and in saliva between 5-120 minutes after brushing. Using 1.5 g versus 0.5 g dentifrice increased F(-) in all samples: oral retention of F(-) was almost doubled by this increase. Increasing duration of brushing had more complex effects. The amount of F(-) in the expectorate increased but decreased in both rinse and toothbrush washing samples. Oral F(-) retention increased, but only in the period 30-120 minutes after brushing. Over the ranges investigated, the order of importance on oral F(-) retention was: dentifrice F(-) concentration > quantity > rinsing regimen > brushing duration. Hence, increasing dentifrice quantity and, to a lesser extent, the duration of brushing, can elevate oral fluoride post-brushing. Evidence is accumulating that the importance of these variables to fluoride efficacy may have been underestimated.

How much is a 'pea-sized amount'? A study of dentifrice dosing by parents in three countries.

To provide optimal fluoride effectiveness against caries while minimising risk of negative effects from excessive ingestion from toothbrushing, the fluoride dose delivered at each occasion is critical. This is particularly important for young children, so using a 'pea-sized amount' is generally recommended. However, there appears little guidance regarding what this means in practice, although it has been indicated to be 0.25 g. This study investigated, using conventional toothpastes and toothbrushes in Germany, the USA and the UK, how much toothpaste parents dispense for their 3- to 6 year-old children, and their interpretation of a 'pea-sized' amount of toothpaste. When asked to dispense the amount they would normally for their child, the majority of parents dosed substantially more than 0.25 g; in Germany, all parents over-dispensed. The amount dispensed varied widely: those parents at the 75th centile dispensed approximately twice the amount dispensed by those at the 25th centile, irrespective of country. When asked to dispense a pea-sized amount, the mean amount dosed decreased significantly in all countries. In the USA, electric toothbrush users dispensed about 0.1 g more than manual toothbrush users. While over-dispensing of fluoride toothpaste remains a cause for concern, it may be argued that the general recommendation to use a pea-sized amount of toothpaste generally works well in practice to balance the conflicting demands of risk and benefit from toothbrushing with fluoride toothpaste in young children.

The effect of brushing time and dentifrice on dental plaque removal in vivo.

PURPOSE: Routine toothbrushing is the principal method by which individuals remove plaque and control plaque-related diseases, such as periodontitis and caries. Oral health care professionals generally recommend at least 2 minutes brushing with an appropriate technique, and yet the average brushing time in the general population is closer to 45 seconds. Our understanding of the relationship between brushing time and plaque removal, in an untutored general population using a conventional manual toothbrush and dentifrice, is limited. The role of dentifrice in plaque removal is also unclear. METHODS: This study was undertaken to measure plaque removal during untutored brushing over timed periods between 30 and 180 seconds with 1.5 g dentifrice, using an Aquafresh Flex brush and Aquafresh Advanced dentifrice. Plaque removal after brushing without dentifrice was also determined (at the 60 second time point only). Forty-seven subjects participated in the study, in which plaque level was assessed using the Quigley-Hein (Turesky-modification) Index. RESULTS: Plaque removal increased with brushing time across the range studied, tending towards a maximum at longer brushing times. At the extremes, brushing for 180 seconds removed 55% more plaque than brushing for 30 seconds. Brushing for 120 seconds removed 26% more plaque than brushing for 45 seconds. The use of dentifrice did not increase plaque removal during 60 seconds of brushing. CONCLUSIONS: Oral health care professionals should reinforce efforts to persuade patients to brush for longer periods of time, as increasing brushing time to the consensus minimum of 2 minutes from a more typical 45 seconds increases plaque removal to an extent likely to provide clinically significant oral health benefits.

Interplay between fluoride and abrasivity of dentifrices on dental erosion-abrasion.

OBJECTIVES: Eroded teeth are more susceptible to toothbrushing wear than sound teeth. We tested the hypothesis that fluoride and abrasivity of dentifrices can interact, modulating the development of erosive-abrasive lesions. METHODS: Human enamel and root dentin specimens were submitted to cycles of demineralization, remineralization and toothbrushing using six dentifrices formulated with three different abrasivity levels: low (L), medium (M) and high (H); with (+F) and without (-F) fluoride. Surface loss was quantified by optical profilometry and compared among groups (alpha=0.05). RESULTS: In dentin, it was ranked: L

The effect of human saliva substitutes in an erosion-abrasion cycling model.

Saliva may affect dental erosion-abrasion by reducing demineralization, enhancing remineralization, and acting as lubricant. This study tested the effect of human saliva substitutes in an erosion-abrasion cycling model designed for enamel and root dentin. Specimens were randomly assigned into the following groups (n = 8): artificial saliva (AS), artificial saliva + mucin (AS+M), deionized water (DIW, negative control), and pooled human saliva (HS, clinical reference). Each group was submitted to a cycle of 5 min in 1% citric acid (pH 3.75), 30 min in the testing solutions, and toothbrushing (enamel, 500 strokes; dentin, 150 strokes, approximately 200 g load) in fluoridated dentifrice (1,100 p.p.m. NaF) slurry. Specimens were rinsed and dried after each procedure. This cycle was repeated three times each day, for 3 d. Substrate loss was measured daily using optical profilometry. Analysis of variance (anova) and Tukey tests (alpha=0.05) showed a significant increase in enamel and dentin wear throughout the experiment for all groups. At the end of the experiment, enamel wear for each group was ranked as: (AS)<(AS+M) and (HS)<(DIW), with AS+M not differing from HS. For dentin, groups AS and AS+M did not differ from each other or from DIW, but showed significantly higher wear than HS. The artificial saliva with mucin showed promise as a potential substitute for human saliva in the enamel erosion-abrasion cycling model. For dentin, none of the artificial salivas performed similarly to human saliva.

The effect of anti-sensitivity dentifrices on brushing abrasion of eroded dentin in vitro.

OBJECTIVE: To investigate the abrasive effects of three marketed anti-sensitivity, and one marketed regular dentifrice on dentin, using an erosion-abrasion in vitro model. METHODS: Standardized human dentin specimens were prepared and exposed to cycles of erosion, remineralization, and tooth brushing, utilizing the four commercially available dentifrices. Dentin surface loss was then measured by optical profilometry after a total of nine complete cycles. The RDA and pH values of the dentifrices were also measured to assist in the interpretation of results. RESULTS: Profilometry showed significantly greater dentin surface loss for both Colgate Sensitive Fresh Stripe and Colgate Sensitive Multi Protection when compared with Sensodyne Total Protection or Crest Cavity Protection dentifrices. The abrasive level of dentifrices correlated positively (r-squared = 0.66; p < 0.05) with dentin surface loss. CONCLUSION: This study demonstrated that the abrasivity of dentifrices can have a significant effect on the wear of eroded dentin in vitro.

Surface microhardness changes, enamel fluoride uptake, and fluoride availability from commercial toothpastes.

OBJECTIVE: The aim of the present study was to evaluate the ability of a new fluoride-containing dentifrice to protect surface-softened enamel against further erosive challenges in an in vitro cycling model, and to relate any effects to enamel fluoride uptake (EFU) and free fluoride. METHODOLOGY: Human enamel specimens were subjected to a daily cycling regimen comprising: three two-minute treatments; five two-minute challenges using 1% citric acid pH 3.8; and remineralization in a mixture of human saliva and mucin-containing artificial saliva. Surface microhardness (SMH) was measured at baseline, 10, and 20 days, and the fluoride content of biopsied specimens determined at 20 days. EFU studies were based on method #40 described in the United States Food and Drug Administration (FDA) testing procedures. Free-fluoride availability was determined from slurries of one part toothpaste plus three parts deionized water. RESULTS: SMH showed that a 1150 ppm NaF test dentifrice protected enamel specimens greater than Crest Cavity Protection (1100 ppm NaF) and a fluoride-free placebo at both 10 days and 20 days (p < 0.05). The fluoride content of specimens treated with this prototype was higher than either Crest or the placebo. SMH for a 1450 ppm NaF test dentifrice was greater than for Elmex Sensitive (1450 ppm amine F) and placebo at 10 days, while both products were greater than the placebo at 20 days. The fluoride content of specimens treated with this test dentifrice was higher than Elmex Sensitive, which was higher than placebo. The fluoride uptake seen in the cycling model correlated for the NaF dentifrices with a standard EFU procedure. Different EFU results for a series of commercial dentifrices demonstrated that EFU is not necessarily a function of free-fluoride availability. CONCLUSION: This study demonstrated that fluoride dentifrices can increase the protection of enamel against an erosive challenge in vitro, and that the increased protection correlated with fluoride uptake. The fluoride uptake seen in the cycling model correlated with a standard FDA EFU procedure for the NaF dentifrices. The present studies demonstrate the importance of formulation effects on driving performance in in vitro models.