Fluoride composition and methods for dental mineralization

Abstract

The present invention relates to compositions and methods for mineralizing a dental surface or subsurface including providing a composition including stabilized ACP and a source of fluoride ions.

Claims

1. A method of mineralizing a dental surface or subsurface comprising providing a composition to contact the dental surface or subsurface, wherein the composition, prior to contacting the dental surface or subsurface, comprises (i) about 0.01% to 50% by weight casein phosphopeptide-stabilized amorphous calcium phosphate or casein phosphopeptide-stabilized amorphous calcium fluoride phosphate, and, separately, (ii) free fluoride ions in an amount of from at least 400 ppm to about 3,000 ppm, and wherein the composition does not include a calcium chelator and does not include an additional phosphate buffer.

2. A method according to claim 1, wherein the composition is selected from the group consisting of toothpaste; tooth gel; tooth powder; dental creme; liquid dentifrice; mouthwash; troche; chewing gum; gingival massage creme; gargle tablet and dental restorative.

3. A method according to claim 1, wherein the composition comprises sodium fluoride.

4. A method for remineralizing a subsurface enamel lesion comprising providing a composition to contact the subsurface enamel lesion, wherein the composition, prior to contacting the subsurface enamel lesion, comprises (i) about 0.01% to 50% by weight casein phosphopeptide-stabilized amorphous calcium phosphate or casein phosphopeptide-stabilized amorphous calcium fluoride phosphate, and, separately, (ii) free fluoride ions in an amount of from at least 400 ppm to about 3,000 ppm, and wherein the composition does not include a calcium chelator and does not include an additional phosphate buffer.

5. A method according to claim 4, wherein the composition is selected from the groups consisting of toothpaste; tooth gel; tooth powder; dental creme; liquid dentifrice; mouthwash; troche; chewing gum; gingival massage creme; gargle tablet and dental restorative.

6. A method of treating and/or preventing dental caries in tooth enamel comprising providing a composition to contact the tooth enamel, wherein the composition, prior to contacting the tooth enamel, comprises (i) about 0.01% to 50% by weight casein phosphopeptide-stabilized amorphous calcium phosphate or casein phosphopeptide-stabilized amorphous calcium fluoride phosphate, and, separately, (ii) free fluoride ions in an amount of from at least 400 ppm to about 3,000 ppm, and wherein the composition does not include a calcium chelator and does not include an additional phosphate buffer.

7. A method of increasing fluoride uptake into a dental surface or subsurface from an oral composition, the method comprising incorporating about 0.01% to 50% by weight casein phosphopeptide-stabilized amorphous calcium phosphate or casein phosphopeptide-stabilized amorphous calcium fluoride phosphate into the oral composition prior to treatment of the dental surface or subsurface, wherein the oral composition separately comprises free fluoride ions in an amount of from at least 400 ppm to about 3,000 ppm, and wherein the oral composition does not include a calcium chelator and does not include an additional phosphate buffer.

8. A method of mineralizing a dental surface or subsurface according to claim 4, wherein the composition further comprises a dentally acceptable polishing material and a surfactant prior to contacting the dental surface or subsurface.

9. A method for manufacturing a composition for mineralizing a dental surface or subsurface comprising preparing a composition comprising (i) about 0.01% to 50% by weight casein phosphopeptide-stabilized amorphous calcium phosphate or casein phosphopeptide-stabilized amorphous calcium fluoride phosphate, and, separately, (ii) free fluoride ions in an amount of from at least 400 ppm to about 3,000 ppm, wherein the composition does not include a calcium chelator and does not include an additional phosphate buffer.

10. A method according to claim 1, wherein the composition comprises free fluoride ions in a range of about 400 ppm to 1500 ppm.

11. A method according to claim 1, wherein the composition comprises about 900 ppm free fluoride.

12. A method according to claim 4, wherein the composition comprises free fluoride ions in a range of about 400 ppm to 1500 ppm.

13. A method according to claim 4, wherein the composition comprises about 900 ppm free fluoride.

14. A method according to claim 6, wherein the composition comprises free fluoride ions in a range of about 400 ppm to 1500 ppm.

15. A method according to claim 6, wherein the composition comprises about 900 ppm free fluoride.

16. A method according to claim 1, wherein the composition comprises about 1% to 10% by weight casein phosphopeptide-stabilized amorphous calcium phosphate or casein phosphopeptide-stabilized amorphous calcium fluoride phosphate.

17. A method according to claim 1, wherein the composition comprises about 20% casein phosphopeptide-stabilized amorphous calcium phosphate or casein phosphopeptide-stabilized amorphous calcium fluoride phosphate.

18. A method according to claim 1, wherein the composition comprises about 5% casein phosphopeptide-stabilized amorphous calcium phosphate or casein phosphopeptide-stabilized amorphous calcium fluoride phosphate.

19. A method according to claim 1, wherein the composition comprises about 3% casein phosphopeptide-stabilized amorphous calcium phosphate or casein phosphopeptide-stabilized amorphous calcium fluoride phosphate.

20. A method according to claim 4, wherein the composition comprises about 1% to 10% by weight casein phosphopeptide-stabilized amorphous calcium phosphate or casein phosphopeptide-stabilized amorphous calcium fluoride phosphate.

21. A method according to claim 4, wherein the composition comprises about 20% casein phosphopeptide-stabilized amorphous calcium phosphate or casein phosphopeptide-stabilized amorphous calcium fluoride phosphate.

22. A method according to claim 4, wherein the composition comprises about 5% casein phosphopeptide-stabilized amorphous calcium phosphate or casein phosphopeptide-stabilized amorphous calcium fluoride phosphate.

23. A method according to claim 4, wherein the composition comprises about 3% casein phosphopeptide-stabilized amorphous calcium phosphate or casein phosphopeptide-stabilized amorphous calcium fluoride phosphate.

Description

EXAMPLE 1

(1) A plaque fluoride study was conducted as a randomized, double-blind three-way crossover design involving three coded mouthrinses. The three mouthrinses were (i) 2% w/v CPP-ACP (Recaldent™) as supplied by Recaldent Pty Ltd (Melbourne, Australia) and 450 ppm F as NaF in deionized water, (ii) 450 ppm F as NaF in deionized water, (iii) a placebo control rinse as deionized water. The CPP-ACP mouthrinse was adjusted to pH 7.0 with 1M HCl. Subjects were supplied with the coded rinses in opaque plastic tubes and used 15 ml of each rinse for 60 s three times a day, after breakfast, after lunch and at night before retiring, for four days and kept a diary of mouthrinse use. On the fifth day the rinse was used after breakfast and supragingival plaque was collected 2-3 hr later. Subjects refrained from all oral hygiene procedures while using the rinses. Each subject crossed over to use each mouthrinse with a four week washout period between treatments. Supragingival plaque was collected using a Gracey 7/8 curette from the buccal and lingual surfaces of ail teeth. Plaque was collected into a preweighed microcentrifuge tube, re-weighed and then stored at −70° C. After thawing of the plaque samples they were centrifuged for 5 min at 20,000 g, dried in a Jouan RC10.10 rotary evaporator and then re-weighed to determine dry weights. The dry samples were then extracted with 200 μl of 1M HCl by mixing in a vortex mixer for 1 min and then treated in ice water in a Bransonic 12 ultrasonic bath (Consolidated Ultrasonic, Melbourne, Australia) for 8 h. After centrifugation (20,000 g, 5 min) fluoride ion concentrations in the supernatant were determined as described previously (Silva and Reynolds, 1996). The plaque fluoride levels were statistically analyzed using a non-parametric Friedmans test with Wilcoxon Signed-Ranks tests (Norusis, 1993).

(2) Both fluoride rinses produced an increase in plaque fluoride levels with the 450 ppm fluoride rinse nearly doubling the fluoride level obtained with the placebo control rinse (Table 2). The addition of 2% CPP-ACP to the 450 ppm fluoride rinse significantly increased the incorporation of fluoride ions into plaque where the plaque fluoride level was over double that obtained with the fluoride rinse. No significant difference was observed in the dry weights of plaque for the three rinses, however the dry weight of the plaque obtained with the 2% CPP-ACP plus 450 ppm fluoride rinse exhibited a tendency to be greater than that obtained with the other two rinses.

(3) TABLE-US-00003 TABLE 2 Fluoride levels in supragingival plaque after treatment with various mouthrinses Plaque Fluoride Level Dry Weight of Plaque Mouthrinse (nmol/mg dry wt) (mg) Placebo Control 7.4 ± 4.7.sup.a, b 4.3 ± 2.5.sup.a Fluoride (450 ppm) 14.4 ± 6.7.sup.a,b  3.9 ± 1.9.sup.a 2% CPP-ACP plus 450 ppm F 33.0 ± 17.6.sup.a,b 5.0 ± 2.1.sup.a .sup.aMean ± SD (n = 14). .sup.bSignificantly different from all values in same column (P < 0.001).

EXAMPLE 2

(4) A remineralization study was conducted as a randomized, double-blind, 5-way crossover remineralization study with five toothpaste slurries using an in situ model previously described (Shen et al., 2001; Reynolds et al., 2003). Palatal appliances containing six human enamel half-slabs with subsurface demineralized lesions were prepared as described by Shen et al. (2001). Toothpastes were prepared as coded products and the base of the product consisted of sorbitol, silica, sodium lauryl sulphate, flavour, sodium carboxymethyl cellulose, titanium dioxide, xanthan gum, sodium saccharin and water. The pH of the formulation was adjusted to 7.0 with phosphoric acid. Five toothpaste formulations were prepared: (i) placebo, (ii) 1100 ppm fluoride as sodium fluoride, (iii) 2800 ppm fluoride as sodium fluoride, (iv) 2% CPP-ACP and (v) 2% CPP-ACP plus 1100 ppm fluoride as sodium fluoride. Toothpaste slurries were prepared by adding 1 g of paste to 4 ml deionized water and vortex mixing for 60 s. Subjects rinsed with the slurries for 60 s four times per day for 14 days at the following times: 10.00 am, 11.30 am, 2.00 pm and 3.30 pm. Subjects kept diaries of toothpaste slurry use and were instructed not to eat, drink or perform oral hygiene procedures while wearing the appliances. When the appliances were not in the mouth they were stored in a sealed moist plastic bag at room temperature. Subjects were instructed to rinse their appliances using deionized water. After the completion of each treatment the enamel half-slabs were removed from the appliances and prepared for acid challenge.

(5) For the acid challenge of the remineralized lesions, the test enamel blocks were covered with acid-resistant nail varnish to leave only half of each remineralized window (1×3 mm.sup.2) exposed. The slabs were mounted onto the end of 3-4 cm sticks of dental wax and immersed in 40 ml of unagitated lactic/Carbopol demineralization buffer (Reynolds, 1997) for 8 hours at 37° C. After completion of this acid challenge the enamel slabs were rinsed with deionized water and sectioned through the midline of both windows to produce two blocks. These two enamel blocks containing remineralized lesions and acid challenged remineralized lesions were paired with their control block containing the original demineralized lesions and embedded, sectioned and microradiographed as described previously (Shen et al., 2001). Images of the lesions and the neighbouring sound enamel were scanned and the percent mineral profile of each lesion determined as described by lijima et al. (2004). The difference between the areas under the densitometric profile of the original demineralized lesion and sound enamel, calculated by trapezoidal integration, is represented by ΔZd. The difference between the areas under the densitometric profile of the remineralized lesion and sound enamel, calculated by trapezoidal integration, is represented by ΔZr. Percentage remineralization (% R) represents the percentage change in ΔZ values

(6) $\mathrm{eg}\%R-\frac{\Delta \mathrm{Zd}-\Delta \mathrm{Xr}}{\Delta \mathrm{Zd}}\times 100\left(\mathrm{ljima}\mathrm{et}\mathrm{al}.,2004\right).$
Data were statistically analyzed using a repeated measures ANOVA with post hoc Scheffe test (Norusis, 1993).

(7) All toothpaste formulations replaced mineral in the enamel subsurface lesions in the in situ study (Table 3). Fluoride produced a dose-response remineralization with the 2800 ppm replacing significantly more mineral than the 1100 ppm formulation which replaced significantly more than the placebo control. The toothpaste with 2% CPP-ACP produced a level of remineralization similar to the 2800 ppm fluoride formulation and the paste with 2% CPP-ACP plus 1100 ppm fluoride was superior to all other formulations including the 2800 ppm fluoride paste. Microradiography of the lesions after remineralization revealed that fluoride ion alone tended to promote remineralization of the surface layer whereas CPP-ACP promoted remineralization, even in the presence of fluoride, throughout the body of the lesion (Figure 1).

(8) Acid challenge in vitro of the in situ remineralized enamel slabs resulted in substantial loss of mineral from the placebo-treated enamel slabs. A smaller amount of mineral was lost from the lesions remineralized with 2% CPP-ACP upon acid challenge. Although there was a tendency to lose a small amount of mineral from the enamel treated with the fluoride formulations the loss was not statistically significant. The residual remineralization after acid challenge was significantly greater for the paste containing 2% CPP-ACP plus 1100 ppm fluoride when compared with the residual remineralization obtained with all other pastes including the paste containing 2800 ppm fluoride. Microradiography of the remineralized lesions after acid challenge revealed that the acid removed mineral predominantly from underneath the remineralized zone.

(9) This in situ study showed a clear dose response in enamel subsurface lesion remineralization by fluoride, with 8.2±0.2% remineralization by the toothpaste containing 1100 ppm F− and 15.5±2.4% by that containing 2800 ppm F−. It also revealed that the paste containing 2% CPP-ACP was superior in remineralizing enamel subsurface lesions when compared with the paste containing 1100 ppm F− and was not significantly different to the paste containing 2800 pm F. The paste containing 2% CPP-ACP plus 1100 ppm F− produced greater remineralization than the paste containing 2800 ppm F−. Addition of 2% CPP-ACP to 1100 ppm F− increased enamel subsurface remineralization by 156% relative to the 1100 ppm F− paste.

(10) The casein phosphopeptides (CPP) have been shown to not only stabilize amorphous calcium phosphate (ACP), but also to deliver and localize ACP at the tooth surface (Reynolds, 1998; Reynolds et al., 1999; Reynolds et al., 2003). CPP-ACP in a mouthwash significantly increased the level of calcium and inorganic phosphate ions in supragingival plaque with the CPP bound to salivary pellicle and to the surface of bacteria in the supragingival plaque biofilm (Reynolds et al., 2003). This clinical trial demonstrated that CPP-ACP can also promote the uptake of fluoride ions into plaque. Therefore CPP-ACP should promote the uptake of calcium, phosphate and fluoride ions into supragingival plaque when added to a fluoride-containing toothpaste formulation. The present in situ study demonstrated that CPP-ACP delivered in a toothpaste formulation was very effective in enamel subsurface remineralization, and that the mineral formed was more resistant to acid than natural enamel apatite. Enamel remineralized by CPP-ACP in the presence of fluoride showed greater resistance to acid challenge relative to natural enamel or enamel remineralized by CPP-ACP. This suggests that CPP-ACP in the presence of F− ions promotes remineralization with acid-resistant fluorapatite. These results demonstrate that addition of CPP-ACP, to a toothpaste formulation significantly enhances the ability of fluoride to remineralize enamel subsurface lesions with acid resistant fluorapatite.

(11) TABLE-US-00004 TABLE 3 Percentage remineralization of enamel subsurface lesions by various toothpaste formulations followed by acid challenge 1100 ppm 2800 ppm 2% CPP-ACP plus Placebo control fluoride fluoride 2% CPP-ACP 1100 ppm fluoride Initial lesion depth (μm)   105 ± 7.sup.a   106 ± 9   102 ± 7   107 ± 8   104 ± 8 ΔZd (vol % min. μm) 4,489 ± 2,465 3,544 ± 1,432 3,704 ± 1,278 4,287 ± 2,282 4,382 ± 1,714 ΔZd − ΔZr   138 ± 122.sup.d   290 ± 136.sup.d   576 ± 222   580 ± 311   919 ± 462.sup.d % R.sup.b  3.1 ± 1.6.sup.e  8.2 ± 2.0.sup.e  15.5 ± 2.4  13.5 ± 1.5  21.0 ± 5.9.sup.e % R.sup.c.sub.AC  −4.1 ± 1.6.sup.f,g  7.1 ± 1.3.sup.f  13.2 ± 1.1.sup.f  8.7 ± 1.5.sup.f,g  17.4 ± 1.2.sup.f .sup.aMean ± SD (n = 14). .sup.b% R = ΔZd − ΔZr/ΔZd × 100 (Shen et al., 2001). .sup.cR.sub.AC = % R after acid challenge. .sup.dsignificantly different from all other values in row (P < 0.01). .sup.esignificantly different from all other values in row (P < 0.01). .sup.fsignificantly different from all other values in row (P < 0.01). .sup.gsignificantly different from % R value in same column (P < 0.01).

EXAMPLE 3

(12) Electron microprobe wavelength dispersive spectrometry was used to measure fluoride levels in remineralized lesions as follows.

(13) Enamel sections were embedded in epoxy resin on a one inch specimen holder. The resin was flat polished to expose the enamel sections using 2400 grit abrasive paper. To achieve optical smoothness 3 μm and 1 μm diamond polishing pastes were used on a cloth pad with final finishing accomplished with a 0.25 μm aluminium oxide paste. All samples and standards were coated with 20 nm of carbon using a Dynavac 300. The electron probe (8900R SuperProbe JEOL, Japan) was operated at a 15 kV accelerating voltage, 12 nA specimen current, 40° take-off angle. Dwell times of 10 seconds for the peak and 10 seconds for the background per point were used. The detection limit for F was 800 ppm. The beam diameter employed during collection of standards was a 10 μm spot whereas the diameter for analysis of lesions was 2 μm. Calcium, phosphorous, fluoride, and chloride X-ray intensities were measured simultaneously using four spectrometers with filter crystals of Pentaerythritol, Pentaerythritol, W/Si layered synthetic, Pentaerythritol, respectively. The standard was analysed using a 10 μm (defocused) and 2 μm (focused) diameter beam to calibrate the X ray count intensity. The standard was synthetic fluorapatite with a calcium to phosphorous ratio of 1.667 and a fluoride content of 3.70 wt %. Elemental maps and quantitative line scans for calcium, phosphorous, fluoride, oxygen and chlorine were collected across the lesions starting from the base of the lesion to the surface layer. Data was corrected using a Phi(RhoZ)-Parabolic method correction procedure implemented in STRATA (Thin Film Analysis Package).

(14) Microradiography of the remineralized lesions after acid challenge revealed that the acid removed mineral predominantly from underneath the remineralized zone. The fluoride level of the remineralized lesions for the placebo, 1100 ppmF and 2% CPP-ACP plus 1100 ppmF pastes was determined using electron microprobe wavelength dispersive spectrometry (Table 4). The fluoride incorporated into the lesion was significantly higher for the 2% CPP-ACP plus 1100 ppmF paste when compared with the 1100 ppmF paste (Table 4). Further, the measured fluoride levels for the 2% CPP-ACP plus 1100 ppmF paste was close to that predicted assuming the remineralized mineral was fluorapatite (Table 4).

(15) TABLE-US-00005 TABLE 4 Predicted and measured fluoride levels in the remineralized lesions Remineralization level Predicted.sup.a Measured.sup.b Toothpaste (vol % min) F (wt %) F (wt %) Placebo 1.31 0.05 0.05 ± 0.05.sup.c 1100 ppmF 2.74 0.10 0.23 ± 0.09.sup.c CPP-ACP 2% plus 8.84 0.33 0.30 ± 0.13.sup.c 1100 ppmF .sup.aPredicted F level based on remineralized mineral being fluorapatite (3.768 wt % F) .sup.bMeasured using electron microprobe wavelength dispersive spectrometry with a JEOL 8900 SuperProbe microprobe. Mean level of fluoride measured by line scans from the base of the lesion to the surface layer. .sup.cSignificantly different from other values in same column (p < 0.01).

EXAMPLE 4

(16) A topical crème may be produced in accordance with the present invention having the following ingredients:

(17) Water

(18) glycerol

(19) CPP-ACP complexes

(20) D-sorbitol

(21) sodium carboxymethylcellulose (CMC-Na)

(22) propylene glycol

(23) silicon dioxide

(24) titanium dioxide

(25) xylitol

(26) phosphoric acid

(27) sodium fluoride

(28) flavouring

(29) sodium saccharin

(30) ethyl p-hydroxybenzoate

(31) propyl p-hydroxybezoate

(32) butyl p-hydroxybenzoate

EXAMPLE 5

(33) A mouthrinse formulation be produced in accordance with the present invention having the following composition:

(34) Water

(35) Alcohol

(36) Poloxamer 407

(37) Sodium Lauryl Sulphate

(38) CPP-ACP complexes

(39) Sodium Fluoride

(40) Flavours

(41) Sodium Saccharin

(42) Ethyl p-hydroxybenzoate

(43) Propyl p-hydroxybenzoate

(44) Butyl p-hydroxybenzoate

EXAMPLE 6

(45) A sugar-free chewing gum formulation be produced in accordance with the present invention having the following composition:

(46) Crystalline sorbitol/mannitol/xylitol

(47) Gum base

(48) Calcium carbonate

(49) Glycerine

(50) CPP-ACP complexes

(51) Sodium Fluoride

(52) Flavour oil

(53) Water

(54) It will be understood that the invention disclosed and defined in this specification extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative aspects of the invention.

REFERENCES

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