CONCEALMENT OF HYPOMINERALISED LESIONS
20220183810 · 2022-06-16
Assignee
Inventors
Cpc classification
A61Q11/00
HUMAN NECESSITIES
A61K6/20
HUMAN NECESSITIES
A61P1/02
HUMAN NECESSITIES
A61C19/063
HUMAN NECESSITIES
A61K8/64
HUMAN NECESSITIES
International classification
A61K6/20
HUMAN NECESSITIES
Abstract
The present invention relates to compositions and uses for reducing the visibility of hypomineralised dental surfaces or subsurfaces, in particular in dental enamel. In one aspect, the invention involves a method of reducing visibility of a hypomineralised dental surface or subsurface, the method comprising (i) contacting the hypomineralised dental surface or subsurface with a liquid composition comprising at least 40% w/v of phosphopeptide (PP)-stabilized amorphous calcium phosphate (ACP) and/or amorphous calcium fluoride phosphate (ACFP) at a pH of less than or equal to pH 6; and (ii) subsequently to (i), raising the pH of the liquid composition applied to the hypomineralised dental surface or subsurface to equal to, or greater than, about 9, thereby forming a gel in and/or on the hypomineralised dental surface or subsurface, thereby reducing visibility of a hypomineralised dental surface or subsurface.
Claims
1. A method of reducing visibility of a hypomineralised dental surface or subsurface, the method comprising contacting the hypomineralised dental surface or subsurface with a liquid composition comprising at least 40% w/w of phosphopeptide (PP)-stabilized amorphous calcium phosphate (ACP) and/or amorphous calcium fluoride phosphate (ACFP) at a pH of greater than or equal to pH 5 but less than or equal to pH 9, thereby reducing visibility of a hypomineralised dental surface or subsurface.
2. A method of treating or preventing dentinal sensitivity in a subject in need thereof, the method comprising: contacting exposed dentinal tubules with a liquid composition comprising at least 40% w/w of phosphopeptide (PP)-stabilized amorphous calcium phosphate (ACP) and/or amorphous calcium fluoride phosphate (ACFP) at a pH of greater than or equal to pH 5 but less than or equal to pH 9, thereby treating or preventing dentinal sensitivity in the subject in need thereof.
3. A method according to claim 1 or 2, wherein the pH of the liquid composition is greater than or equal to 6 but less than or equal to 8, preferably, greater than or equal to 7 but less than or equal to 8.
4. A method according to any one of claims 1 to 3, wherein the liquid composition further comprises free fluoride ions.
5. A method according to claim 4, wherein the free fluoride ions are present in the liquid composition at a concentration in the range of about 200 ppm to 10,000 ppm.
6. A method according to claim 4, wherein the free fluoride ions are present in the liquid composition at a concentration in the range of about 2,600 ppm to about 8,500 ppm.
7. A method according to claim 4, wherein the free fluoride ions are present in the liquid composition at a concentration of about 7,800 ppm.
8. A method according to any one of claims 1 to 7, the method further comprising heating of the dental surface or subsurface, or lesion.
9. A method according to claim 8, wherein the dental surface or subsurface is heated to a temperature greater than 37° C.
10. A method according to claim 8, wherein the dental surface or subsurface is heated to a temperature greater than or equal to 40° C.
11. A method according to claim 8, wherein the dental surface or subsurface is heated to a temperature greater than or equal to 45° C.
12. A method according to claim 8, wherein the dental surface or subsurface is heated to a temperature greater than or equal to 50° C.
13. A method according to claim 8, wherein the dental surface or subsurface is heated to a temperature greater than or equal to 55° C.
14. A method according to claim 9, wherein the dental surface or subsurface is heated to a temperature greater than or equal to 60° C.
15. A method according to claim 9, wherein the dental surface or subsurface is heated to a temperature greater than or equal to 65° C.
16. A method according to any one of claims 1 to 15, wherein the liquid composition comprises greater than 45% w/w stabilized ACP and/or ACFP.
17. A method according to any one of claims 1 to 15, wherein the liquid composition comprises greater than 50% w/w stabilized ACP and/or ACFP.
18. A method according to any one of claims 1 to 15, wherein the liquid composition comprises greater than 55% w/w stabilized ACP and/or ACFP.
19. A method according to any one of claims 1 to 15, wherein the liquid composition comprises greater than 60% w/w stabilized ACP and/or ACFP.
20. A method according to any one of claims 1 to 15, wherein the liquid composition comprises about 65% w/v stabilized ACP and/or ACFP.
21. A method according to any one of claims 1 to 15, wherein the liquid composition comprises about 70% w/v stabilized ACP and/or ACFP.
22. A method according to any one of claims 1 to 15, wherein the liquid composition comprises about 75% w/v stabilized ACP and/or ACFP.
23. A method according to any one of claims 1 to 22, wherein the phosphopeptide is a casein phosphopeptide.
24. A method of reducing visibility of a hypomineralised dental surface or subsurface, the method comprising: (i) contacting the hypomineralised dental surface or subsurface with a liquid composition comprising at least 40% w/v of phosphopeptide (PP)-stabilized amorphous calcium phosphate (ACP) and/or amorphous calcium fluoride phosphate (ACFP) at a pH of less than or equal to pH 6; and (ii) subsequently to (i), raising the pH of the liquid composition applied to the hypomineralised dental surface or subsurface to equal to, or greater than, about 9, thereby forming a gel in and/or on the hypomineralised dental surface or subsurface, thereby reducing visibility of a hypomineralised dental surface or subsurface.
25. A method of forming a gel in and/or on a dental surface or sub-surface lesion, the method comprising: (i) contacting the dental surface or sub-surface lesion with a liquid composition comprising at least 40% w/v of phosphopeptide (PP)-stabilized amorphous calcium phosphate (ACP) and/or amorphous calcium fluoride phosphate (ACFP) at a pH of less than or equal to pH 6; and (ii) subsequently to (i), raising the pH of the liquid composition applied to the dental surface or sub-surface lesion to equal to, or greater than, about 9, thereby forming a gel in and/or on the dental surface or sub-surface lesion, thereby forming a gel in and/or on the dental surface or sub-surface lesion.
26. A method of treating or preventing dentinal sensitivity in a subject in need thereof, the method comprising: (i) contacting exposed dentinal tubules with a liquid composition comprising at least 40% w/v of phosphopeptide (PP)-stabilized amorphous calcium phosphate (ACP) and/or amorphous calcium fluoride phosphate (ACFP) at a pH of less than or equal to pH 6; and (ii) subsequently to (i), raising the pH of the liquid composition applied to the hypomineralised dental surface or subsurface to equal to, or greater than, about 9, thereby forming a gel in and/or on the exposed dentinal tubules, thereby treating or preventing dentinal sensitivity in the subject in need thereof.
27. A method of forming a protective layer on a dental surface, the method comprising: (i) contacting the dental surface with a liquid composition comprising at least 40% w/v of phosphopeptide (PP)-stabilized amorphous calcium phosphate (ACP) and/or amorphous calcium fluoride phosphate (ACFP) at a pH of less than or equal to pH 6; and (ii) subsequently to (i), raising the pH of the liquid composition applied to the dental surface to equal to, or greater than, about 9, thereby forming a protective layer on the dental surface.
28. A method according to any one of claims 24 to 27, wherein the pH of the liquid composition applied to the dental surface or sub-surface lesion is raised to equal to, or greater than, about 10.
29. A method according to any one of claims 24 to 27, wherein raising the pH of the liquid composition applied to the dental surface or sub-surface is by contacting the liquid composition applied to the dental surface or sub-surface with a further composition of alkaline pH.
30. A method according to any one of claims 24 to 29, wherein the dental surface is dental enamel.
31. A method according to any one of claims 24 to 30, wherein the dental surface is a lesion in enamel is caused by caries, dental erosion or fluorosis.
32. A method according to claim 31, wherein the lesion is a white spot lesion.
33. A method according to any one of claims 24 to 32, wherein raising the pH of the liquid composition applied to the dental surface or sub-surface is by contacting the liquid composition applied to the dental surface or sub-surface with a further composition of alkaline pH.
34. A method of reducing visibility of a hypomineralised dental surface or subsurface, the method comprising: (i) mixing (a) a liquid composition comprising at least 40% w/v of phosphopeptide (PP)-stabilized amorphous calcium phosphate (ACP) and/or amorphous calcium fluoride phosphate (ACFP) at a pH of less than or equal to pH 6, and (b) a further composition of alkaline pH, thereby forming a mixed composition with a pH of equal to, or greater than, about 9; (ii) contacting the hypomineralised dental surface or subsurface with the mixed composition, thereby forming a gel in and/or on the hypomineralised dental surface or subsurface, thereby reducing visibility of a hypomineralised dental surface or subsurface.
35. A method of treating or preventing dentinal sensitivity in a subject in need thereof, the method comprising: (i) mixing (a) a liquid composition comprising at least 40% w/v of phosphopeptide (PP)-stabilized amorphous calcium phosphate (ACP) and/or amorphous calcium fluoride phosphate (ACFP) at a pH of less than or equal to pH 6, and (b) a further composition of alkaline pH, thereby forming a mixed composition with a pH of equal to, or greater than, about 9; (ii) contacting exposed dentinal tubules with the mixed composition, thereby forming a gel in and/or on the exposed dentinal tubules, thereby treating or preventing dentinal sensitivity in the subject in need thereof.
36. A method of forming a protective layer on a dental surface, the method comprising: (i) mixing (a) a liquid composition comprising at least 40% w/v of phosphopeptide (PP)-stabilized amorphous calcium phosphate (ACP) and/or amorphous calcium fluoride phosphate (ACFP) at a pH of less than or equal to pH 6, and (b) a further composition of alkaline pH, thereby forming a mixed composition with a pH of equal to, or greater than, about 9; (ii) contacting a dental surface with the mixed composition, thereby forming a protective layer on the dental surface.
37. A method according to claims 34 to 36, wherein the alkaline pH of the further composition is a pH of about 8.
38. A method according to claims 34 to 36, wherein the alkaline pH of the further composition is a pH of about 9.
39. A method according to claims 34 to 36, wherein the alkaline pH of the further composition is a pH of about 10.
40. A method according to claims 34 to 36, wherein the alkaline pH of the further composition is a pH of about 11.
41. A method according to claims 34 to 36, wherein the alkaline pH of the further composition is a pH of about 12.
42. A method according to claims 34 to 36, wherein the alkaline pH of the further composition is a pH of about 13.
43. A method according to claims 34 to 36, wherein the alkaline pH of the further composition is a pH of about 14.
44. A method according to any one of claims 24 to 43, wherein the liquid composition further comprises free fluoride ions.
45. A method according to claim 44, wherein the free fluoride ions are present in the liquid composition at a concentration in the range of about 200 ppm to about 10,000 ppm.
46. A method according to claim 44, wherein the free fluoride ions are present in the liquid composition at a concentration in the range of about 2,600 ppm to about 8,500 ppm.
47. A method according to claim 44, wherein the free fluoride ions are present in the liquid composition at a concentration of about 8,200 ppm.
48. A method according to any one of claims 24 to 33, wherein step (i) further comprises heating of the dental surface or subsurface, or lesion.
49. A method according to any one of claims 24 to 33, wherein step (i) is followed by heating of the dental surface or subsurface, or lesion.
50. A method according to any one of claims 24 to 49, wherein step (ii) further comprises heating of the dental surface or subsurface, or lesion.
51. A method according to any one of claims 24 to 49, wherein step (ii) is followed by heating of the dental surface or subsurface, or lesion.
52. A method according to any one of claims 48 to 51, wherein the dental surface or subsurface, or lesion is heated to a temperature greater than 37° C.
53. A method according to any one of claims 48 to 51, wherein the dental surface or subsurface, or lesion is heated to a temperature greater than or equal to 40° C.
54. A method according to any one of claims 48 to 51, wherein the dental surface or subsurface, or lesion is heated to a temperature greater than or equal to 45° C.
55. A method according to any one of claims 48 to 51, wherein the dental surface or subsurface, or lesion is heated to a temperature greater than or equal to 50° C.
56. A method according to any one of claims 48 to 51, wherein the dental surface or subsurface, or lesion is heated to a temperature greater than or equal to 55° C.
57. A method according to any one of claims 48 to 51, wherein the dental surface or subsurface, or lesion is heated to a temperature greater than or equal to 60° C.
58. A method according to any one of claims 48 to 51, wherein the dental surface or subsurface, or lesion is heated to a temperature greater than or equal to 65° C.
59. A method according to any one of claims 48 to 51, wherein the dental surface or subsurface, or lesion is heated to a temperature less than 65° C.
60. A method according to any one of claims 24 to 59, wherein the liquid composition comprising greater than 40% w/v phosphopeptide (PP)-stabilized ACP and/or ACFP comprises greater than 45% w/v stabilized ACP and/or ACFP.
61. A method according to any one of claims 24 to 59, wherein the liquid composition comprising greater than 40% w/v phosphopeptide (PP)-stabilized ACP and/or ACFP comprises greater than 50% w/v stabilized ACP and/or ACFP.
62. A method according to any one of claims 24 to 59, wherein the liquid composition comprising greater than 40% w/v phosphopeptide (PP)-stabilized ACP and/or ACFP comprises greater than 55% w/v stabilized ACP and/or ACFP.
63. A method according to any one of claims 24 to 59, wherein the liquid composition comprising greater than 40% w/v phosphopeptide (PP)-stabilized ACP and/or ACFP comprises greater than 60% w/v stabilized ACP and/or ACFP.
64. A method according to any one of claims 24 to 59, wherein the liquid composition comprising greater than 40% w/v phosphopeptide (PP)-stabilized ACP and/or ACFP comprises about 65% w/v stabilized ACP and/or ACFP.
65. A method according to any one of claims 24 to 59, wherein the liquid composition comprising greater than 40% w/v phosphopeptide (PP)-stabilized ACP and/or ACFP comprises about 70% w/v stabilized ACP and/or ACFP.
66. A method according to any one of claims 24 to 59, wherein the liquid composition comprising greater than 40% w/v phosphopeptide (PP)-stabilized ACP and/or ACFP comprises about 75% w/v stabilized ACP and/or ACFP.
67. A method according to any one of claims 24 to 33, wherein the hypomineralised dental surface or subsurface, or lesion, is contacted with the liquid composition in (i) for up to 20 minutes before the raising the pH of the liquid composition applied to the hypomineralised dental surface or subsurface to equal to, or greater than, about 9.
68. A method according to claim 67, wherein the hypomineralised dental surface or subsurface, or lesion, is contacted with the liquid composition in (i) for at least about a few seconds to at about 5 minutes.
69. A method according to claim 68, wherein the hypomineralised dental surface or subsurface, or lesion, is contacted with the liquid composition in (i) for at least about 5 minutes to about 20 minutes.
70. A method according to any one of claims 24 to 69, wherein the method further comprises acid etching the hypomineralised surface, subsurface or lesion, prior to contacting with the liquid composition in (i).
71. A method according to any one of claims 24 to 70, wherein the phosphopeptide is a casein phosphopeptide.
72. A method according to any one of claims 1 to 71, wherein the liquid, further and/or mixed compositions are applied to the dental surface, subsurface or lesion by a dental health care professional.
73. A method according to claim 72, wherein the liquid, further and/or mixed compositions are applied to the dental surface, subsurface or lesion using a microbrush.
74. A method according to any one of claims 1 to 73, wherein the method further comprises a step of identifying a subject having a white spot lesion, a fluorotic lesion, a caries lesion, or a lesion caused by tooth erosion.
75. A cosmetic method of reducing visibility of a hypomineralised dental surface or subsurface, the method comprising: (i) contacting the hypomineralised dental surface or subsurface with a liquid composition comprising at least 40% w/v of phosphopeptide (PP)-stabilized amorphous calcium phosphate (ACP) and/or amorphous calcium fluoride phosphate (ACFP) at a pH of less than or equal to pH 6; and (ii) subsequently to (i), raising the pH of the liquid composition applied to the hypomineralised dental surface or subsurface to equal to, or greater than, about 9, thereby forming a gel in and/or on the hypomineralised dental surface or subsurface, thereby reducing visibility of a hypomineralised dental surface or subsurface.
76. A cosmetic method reducing visibility of a hypomineralised dental surface or subsurface, the method comprising contacting the hypomineralised dental surface or subsurface with a liquid composition comprising at least 40% w/w of phosphopeptide (PP)-stabilized amorphous calcium phosphate (ACP) and/or amorphous calcium fluoride phosphate (ACFP) at a pH of greater than or equal to pH 6 but less than or equal to pH 8, thereby reducing visibility of a hypomineralised dental surface or subsurface.
77. A kit for reducing visibility of a hypomineralised dental surface or subsurface, the kit comprising or consisting of: (a) a liquid composition comprising at least 40% by weight of phosphopeptide (PP)-stabilized amorphous calcium phosphate (ACP) and/or amorphous calcium fluoride phosphate (ACFP) at a pH of less than or equal to pH 6, and (b) a further composition of alkaline pH.
78. A kit according to claim 77, wherein the kit further comprises written instructions for use in any method according to claims 1 to 76.
79. A kit for reducing visibility of a hypomineralised dental surface or subsurface comprising or consisting of: (a) a first composition comprising a powder of phosphopeptide stabilized ACP and/or ACFP; (b) a second composition comprising a solution of fluoride at a pH of less than or equal to pH 6; and (c) a third composition of alkaline pH.
80. A kit according to any one of claims 77 to 79, wherein the alkaline pH of the third composition is a pH of about 9, 10, 11, 12, 13 or 14.
81. A kit according to claim 77 or 78, wherein the first composition comprises an amount of phosphopeptide stabilized ACP and/or ACFP that when mixed with the second composition, a liquid composition comprising at least 40% w/v of phosphopeptide stabilized ACP and/or ACFP is formed.
82. A kit for reducing visibility of a hypomineralised dental surface or subsurface, the kit comprising or consisting of: (a) 5 g of CPP-ACP and/or CPP-ACFP, (b) 5 ml of 0.73 M NaF in 1.146 M HCl, and (c) 1.5 M NaOH.
83. A kit according to claim 82, wherein the kit further includes two microbrushes.
84. A method or process for preparing a liquid composition comprising at least 40% w/v PP stabilized ACP and/or ACFP, the method or process comprising or consisting of: mixing a solvent and a powder comprising or consisting of PP stabilized-ACP and/or ACFP, and maintaining the pH below 7.
85. A method or process for preparing a liquid composition comprising at least 40% w/v PP stabilized ACP and/or ACFP, the method or process comprising or consisting of: mixing a solvent to a powder comprising or consisting of PP stabilized ACP and/or ACFP, and lowering the pH below 7, preferably, the pH is lowered to, or below, 6, preferably 5.5.
86. A method or process according to claim 84 or 85, wherein the pH is maintained at, or below, 6, preferably the pH is maintained at, or below, 5.5.
87. A method or process according to any one of claims 84 to 86, further comprising the following steps to prepare a powder comprising or consisting of PP stabilized-ACP and/or ACFP: admixing one or more solutions comprising phosphopeptides, calcium ions, phosphate ions, hydroxide ions and optionally fluoride ions, while maintaining the pH at about 7.0 or above, preferably about 9, to form a solution comprising stabilized-ACP and/or ACFP, and drying the solution comprising PP stabilized-ACP and/or ACFP, thereby forming a powder comprising or consisting of PP stabilized-ACP and/or ACFP.
88. A method or process according to claim 87, wherein the drying is spray drying or freeze drying.
89. A method or process according to claim 87 or 88, further comprising the step of filtering the solution comprising PP stabilized-ACP and/or ACFP, prior to drying, to form a retentate, wherein the retentate is subsequently dried to form powder comprising or consisting of PP stabilized-ACP and/or ACFP.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION OF THE INVENTION
[0187] Further aspects of the present invention and further embodiments of the aspects described in the preceding paragraphs will become apparent from the following description, given by way of example and with reference to the accompanying drawings. 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.
[0188] Reference will now be made in detail to certain embodiments of the invention. While the invention will be described in conjunction with the embodiments, it will be understood that the intention is not to limit the invention to those embodiments. On the contrary, the invention is intended to cover all alternatives, modifications, and equivalents, which may be included within the scope of the present invention as defined by the claims.
[0189] One skilled in the art will recognize many methods and materials similar or equivalent to those described herein, which could be used in the practice of the present invention. The present invention is in no way limited to the methods and materials described.
[0190] All of the patents and publications referred to herein are incorporated by reference in their entirety.
[0191] For purposes of interpreting this specification, terms used in the singular will also include the plural and vice versa.
[0192] As used herein, except where the context requires otherwise, the term “comprise” and variations of the term, such as “comprising”, “comprises” and “comprised”, are not intended to exclude further additives, components, integers or steps. As used herein, except where the context requires otherwise, “comprise” and “include” can be used interchangeably.
[0193] An aspect of the current invention is based on several surprising findings, the first that a composition comprising a high concentration of phosphopeptide (PP)-stabilized amorphous calcium phosphate (ACP) and/or amorphous calcium fluoride phosphate (ACFP) can remain in a liquid state (i.e. does not form a gel). Prior to the present invention it was thought that high concentrations of phosphopeptide-stabilized ACP and/or ACFP would result in the composition forming a gel or paste, and all liquid compositions described to date had relatively low concentrations of phosphopeptide-stabilized ACP and/or ACFP. The second surprising finding is that raising the pH of the acidic liquid composition changes the form of the composition to a gel, and this can occur in and/or on a dental surface, subsurface or lesion. Without being bound by any theory or mode of action it is believed that raising the pH destabilises the PP-ACP and/or PP-ACFP complexes to form an amorphous embryonic hydroxyapatite or fluorohydroxyapatite gel. The third surprising finding is that this formation of a gel occurs rapidly after raising the pH of the composition, for example by applying a further composition with an alkaline pH. The fourth surprising finding is that the gel that is formed changes the refractive index and reduces the visibility of the hypomineralised surface, subsurface or lesion by returning the hypomineralised surface, subsurface or lesion to translucency. An advantage of the present invention is that it masks or conceals visible hypomineralised lesions to substantially improve the appearance and reduce visibility, i.e. to return the surface to translucency, within minutes in a dental surgery during a single patient visit. Further, it does so with calcium and phosphate (with or without fluoride). This represents a substantial improvement in current in-surgery dental treatments of, for example, white spot lesions. At the same time as providing a cosmetic benefit, the gel then provides a reservoir of high concentrations of calcium, phosphate and optionally fluoride, to remineralize the surface, subsurface or lesion.
[0194] The liquid composition comprising a high concentration of phosphopeptide-stabilized ACP and/or ACFP is typically at a pH of 6 or less can be combined or mixed with a further liquid composition of alkaline pH prior to application to the dental surface. A further surprising finding is that the combined or mixed composition formed, which comprises a high concentration of phosphopeptide-stabilized ACP and/or ACFP where the pH is equal to, or greater than, about 9, is maintained in a state that allows it to be applied to a dental surface. In other words, the combined or mixed composition exists in a liquid form for a time, for example 1 to 2 minutes, which allows application to a dental surface.
[0195] A yet another surprising finding is that a composition comprising a high concentration of phosphopeptide (PP)-stabilized amorphous calcium phosphate (ACP) and/or amorphous calcium fluoride phosphate (ACFP) can remain in a liquid state (i.e.
[0196] does not form a gel) and does so at a near neutral pH. This composition does not need to be prepared at the dental professional surgery, at the physical location where the individual is treated. This liquid composition can then be used to reduce the visibility of white spot lesions, reduce dentinal hypersensitivity and other uses as described herein.
[0197] A dental subsurface is typically a hypomineralised lesion such that the first composition and the second composition, or mixed composition, contacted to the dental surface migrates through any surface layer, i.e. pellicle and/or plaque, through the porous dental surface to the region requiring mineralization. Preferably, the PP-stabilized ACP or ACFP is in the form of a casein phosphopeptide stabilized ACP or ACFP complex. The dental surface is preferably dental enamel. The dental surface may be a lesion in the enamel, such as a lesion caused by caries, dental erosion or fluorosis.
[0198] A reduction in visibility of a hypomineralised surface, subsurface or lesion can be determined simply by visual inspection by the human eye. A reduction in visibility may be any level of reduction such that the hypomineralised surface, subsurface or lesion is less noticeable. A reduction in visibility may result in the hypomineralised surface, subsurface or lesion adopting a translucent appearance such that there is little or no difference with surrounding normal, mineralised dental surface as determined by the human eye.
[0199] Visibility of a surface, subsurface or lesion may also be determined as follows. A Chroma Meter (Minolta ChromaMeter CR241, Minolta, Japan) can be used to record surface reflectance. Surface reflectance measurement was established in L*a*b* color space by the Commission de L'Eclairage in 1978, and measurements relate to human colour perception in three colour dimensions (Commision Internationale de L'Eclaige (1978). Recommendations on uniform colour spaces, colour difference equations and psychometric colour terms. Paris: Bureau Centrale de la DIE Suppl. 2:15.). The L* values represent colour gradients from white to black, a* values represent colour gradients from green to red, and b* values represent colour gradients from blue to yellow (Commision Internationale de L'Eclaige, 1978). Only L* value measurements may be used with whiter colours having a higher reading, and darker colours a lower reading. To ensure a reproducible position of specimens in the Chroma Meter, a wax mold for each sample may be prepared and stored. All samples may be air-dried with a dental triplex syringe for 60 s before each measurement. Individual specimens may be repositioned ten times both before and after treatment, and colour reflectance L* values were recorded.
[0200] Dentinal hypersensitivity results when protective enamel or cementum covering dentine is lost. Cementum is typically easier to breach than enamel, because cementum is thinner and more easily eroded by acids. However, breach of cementum cannot happen until there is gingival recession and exposure of the root surface to the oral environment. Individuals with breached cementum and suffering with dentinal hypersensitivity often experience pain when the exposed area of the tooth comes into contact with cold air, hot and cold liquids, foods that are sweet or acidic, or is touched with a metal object. Patients suffering from tooth hypersensitivity have larger number of open dentinal tubules and/or tubules with a larger diameter than normal.
[0201] An advantage of an aspect of the present invention is the formation of a protective layer. This layer typically has the same, or similar, composition as hydroxyapatite or fluorapatite. It can form on enamel or dentine and can be used to seal or occlude dentinal tubules thereby reducing dentinal sensitivity.
[0202] Such a layer may be characterised has a calcium : phosphate ratio equivalent to normal apatite, preferably where the ratio is about 1.5-2:1. The layer ideally contains an amount of calcium that is about 20 wt %.
[0203] Preferably, the layer contains carbon, oxygen, phosphate and calcium, and optionally fluoride.
[0204] Methods of the invention that result in sealing of exposed dentine reduce tooth sensitivity and reduce the risk of caries, for example tooth root surface caries. Further, as dental restoratives can shrink and form microgaps with the dental surface, the present invention would find particular application prior to applying a restorative material such as a composition that include glass ionomer cement. The gel or protective layer would then act as a cavity sealer and reduce the formation of microgaps.
[0205] The words ‘treat’ or ‘treatment’ refer to therapeutic treatment wherein the object is to slow down (lessen) an undesired physiological change or disorder. For the purposes of this invention, beneficial or desired clinical results include, but are not limited to, alleviation of symptoms, diminishment of extent of the condition, stabilized (i.e., not worsening) state of the condition, delay or slowing of condition progression, amelioration or palliation of the disease/condition state, and remission (whether partial or total), whether detectable or undetectable. Treatment may not necessarily result in the complete absence of detectable symptoms of the condition but may reduce or minimise complications and side effects of the condition. The success or otherwise of treatment may be monitored by physical examination of the individual or response to any thermal, tactile or chemical treatment as described herein. Where a method of the invention is used to treat a subject for dentinal sensitivity, or hypersensitivity, preferably, the subject experiences a reduction in the severity of the pain or a reduction in the incidence of pain over time. Methods for identifying subjects having different degrees of dentinal sensitivity, and for measuring success of treatment or prevention, are described herein and also include those outlined in Med Oral Patol Oral Cir Bucal. 2008 Mar. 1; 13(3): E201-6. Treatment of a subject may be determined by comparing the level of pain experienced when exposed to any stimuli described herein before and after treatment, whereby a reduction in pain after treatment indicates a reduction in sensitivity.
[0206] The words ‘prevent’ and ‘prevention’ generally refer to prophylactic or preventative measures for protecting or precluding an individual not having a condition or symptom, for example sensitivity, from progressing to having the condition or symptom, for example sensitivity. Individuals in whom prevention may be required are those undergoing a dental procedure, particularly a dental procedure that exposes dentine.
[0207] In any aspect of the invention, the hypomineralised dental surface or subsurface, or lesion, is contacted with the liquid composition in (i) for a period of time that allows the liquid composition to penetrate the dental surface, subsurface or lesion. Typically, the liquid composition is applied for a period of time that allows the liquid composition to penetrate porosities of the hypomineralised dental surface or subsurface, or lesion. This then provides the liquid composition within those porosities so that the visibility of the the hypomineralised dental surface or subsurface, or lesion can be reduced when the pH of the liquid composition in the porosities is raised thereby forming a gel. The gel may therefore be formed in the subsurface or lesion, or in and on the subsurface or lesion. In one embodiment, the hypomineralised dental surface or subsurface, or lesion, is contacted with the liquid composition in (i) for up to 20 minutes before raising the pH of the liquid composition applied to the hypomineralised dental surface or subsurface to equal to, or greater than, about 9. In one embodiment, the hypomineralised dental surface or subsurface, or lesion, is contacted with the liquid composition in (i) for at least about a few second to at about 5 minutes, preferably at least about 5 minutes to about 20 minutes.
[0208] Typically the gel is formed any time from when the further composition is applied until about 5 to 20 minutes. Therefore, in one embodiment the further composition is applied to raise the pH of the first composition and a period of about 5 to about 20 minutes is allowed to pass before any further compositions are applied to, or procedures conducted on, the dental surface, subsurface or lesion.
[0209] As used herein % w/v may be taken to be equivalent to g/100 ml.
[0210] In any aspect the dental surface is in need of such treatment. Therefore, in another aspect, the invention includes in addition to the steps of any method described herein a step of identifying a subject suffering fluorosis, dental caries, dentinal hypersensitivity or dental calculus, a white spot lesion; a fluorotic lesion; a caries lesion; or a lesion caused by tooth erosion.
[0211] A further composition of alkaline pH is a composition with a pH greater than 7 that includes a base or a compound capable of producing a base. A base is defined as a compound which can accept hydrogen cations (protons) or, more generally, donate a pair of valence electrons. The composition may include a compound that may not necessarily normally be regarded as a base, for example a polypeptide with numerous acidic and basic residues but nonetheless has the ability to increase the pH of the composition to greater than 7, preferably to pH about 9 or greater. Non-limiting examples of bases suitable for use in the invention include hydroxides, borates, phosphates including hydrogen phosphates, amines and any salt forms thereof including an alkali metal salt forms. More specifically, non-limiting examples of suitable pharmaceutically acceptable bases include ammonium hydroxide, sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, magnesium hydroxide, ferrous hydroxide, zinc hydroxide, sodium hypochlorite, copper hydroxide, aluminum hydroxide, ferric hydroxide, isopropylamine, trimethylamine, diethylamine, triethylamine, tripropylamine, ethanolamine, 2-dimethylaminoethanol, 2-diethylaminoethanol, lysine, arginine, histidine or urea. In one embodiment, the further composition comprises sodium hydroxide, preferable at a concentration of greater than or equal to 1 or 2 M.
[0212] Any pharmaceutically acceptable compounds described as a base are suitable for use in the invention. Typically, the base is suitable for oral use. Preferably, the compound acts as a base, i.e. only releases hydroxide ions or donates electrons, in the presence of an acid. The base may be a free-base form, or in a pharmaceutically acceptable salt form. Non-limiting examples of bases suitable for use in the invention include hydroxides, borates, phosphates including hydrogen phosphates and dihydrogen phosphates, citrates, carbonates, bicarbonates, hypochlorites, amines and any salt forms thereof including an alkali metal salt forms. More specifically, non-limiting examples of suitable pharmaceutically acceptable bases include ammonium hydroxide, sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, magnesium hydroxide, ferrous hydroxide, zinc hydroxide, copper hydroxide, aluminum hydroxide, ferric hydroxide, isopropylamine, trimethylamine, diethylamine, triethylamine, tripropylamine, ethanolamine, 2-dimethylaminoethanol, 2-diethylaminoethanol, lysine, arginine, histidine. A hypofluorite capable of acting as a base as described herein is also useful in the invention as the agent for increasing or maintaining pH. A suitable hypofluorite would react in situ to produce fluoride ions and hydroxide (or another base) ions. One skilled in the art will appreciate that fluoride ions can substitute for hydroxide in the crystal structure of apatite forming fluorapatite.
[0213] Any heat source may be used in a method or use of the invention to heat or cure the dental surface or subsurface. Heat sources that emit light or radiation and are suitable for use in dental applications are known in the art. Specific examples include dental curing lights, for example a 10W high-power blue light LED such as X-Cure by Guilin Woodpecker Medical Instrument Co. Ltd. In any method or use of the invention, there may be an additional step of heating or curing the liquid composition once it has contacted the dental surface or sub-surface. The heating or curing may be for a period of equal to or at least 30 seconds, equal to or at least 40 seconds, equal to or at least 50 seconds, equal to or at least 60 second, equal to or at least 2 minutes or equal to or at least 5 minutes. The heating or curing may increase temperature in bursts to 45-50° C. (with patient comfort). The heading or curing may be for any time or at any temperature as described herein including the examples.
[0214] Any composition described herein may be applied to a dental surface, subsurface or lesion using any technique known in the art or described herein. An exemplary application technique is using a microbrush.
[0215] Further, any resin barrier, such as a rubber dam, may be used to protect soft tissue in the oral cavity from application of any composition described herein.
[0216] As used herein, “stabilized-ACP or ACFP” and “stabilized-ACP or ACFP complex” are used interchangeably.
[0217] A stabilized-ACP or ACFP complex as described in the current specification may be the “closed” complexes as shown in
[0218] A stabilized-ACP or ACFP complex as referred to herein includes a stabilized-ACP or ACFP complex as described in WO2006/056013 (PCT/AU2005/001781) the contents of which are incorporated by reference.
[0219] In a preferred embodiment, the phosphopeptide stabilized amorphous calcium phosphate (ACP) or amorphous calcium fluoride phosphate (ACFP) complex has tightly bound and loosely bound calcium, wherein the bound calcium in the complex is less than the tightly bound calcium in an ACP or ACFP complex formed at a pH of 7.0. Optionally, the ACP or ACFP is predominantly in a basic form.
[0220] A stabilized-ACP or ACFP complex as referred to herein include a stabilized-ACP or ACFP complex formed at a pH of below 7.0. Preferably, the complex is formed at a pH in the range of about 5.0 up to but below 7.0. More preferably, the complex is formed at a pH range of about 5.0 to about 6.0. In a preferred embodiment, the complex is formed at a pH of about 5.0 or about 5.5. Preferably, the ACP or ACFP in the complex is predominantly in a basic form.
[0221] A stabilized-ACP may be produced by a method comprising the steps of:
[0222] (i) obtaining a solution comprising at least one phosphopeptide and;
[0223] (ii) admixing solutions comprising calcium ions, phosphate ions and hydroxide ions, while maintaining the pH at about 5.5 to 9.
[0224] In one embodiment, the pH is maintained at 7.0 or below.
[0225] A stabilized ACFP may be produced by a method comprising the steps of:
[0226] (i) obtaining a solution comprising at least one phosphopeptide; and
[0227] (ii) admixing solutions comprising calcium ions, phosphate ions, hydroxide ions and fluoride ions, while maintaining the pH at about 5.5 to 9.
[0228] In one embodiment, the pH is maintained at 7.0 or below.
[0229] The hydroxide ions may be titrated into the solution to maintain the phosphopeptide solution at an essentially constant pH. The calcium and phosphate ions may be titrated into the phosphopeptide solution with constant mixing and at a rate that avoids the formation of a calcium phosphate precipitate in the phosphopeptide solution.
[0230] A phosphopeptide stabilized amorphous calcium phosphate (ACP) or amorphous calcium fluoride phosphate (ACFP) complex may also include wherein the ACP in the complex has tightly bound and loosely bound calcium, wherein the tightly bound calcium in the complex is less than the tightly bound calcium in an ACP or ACFP complex formed at a pH of 7.0 and the ACP or ACFP is predominantly in a basic form, obtainable or obtained by a method comprising:
[0231] a) admixing a first solution comprising calcium ions, a second solution comprising phosphate ions, and optionally a third solution comprising fluoride ions, to a solution comprising phosphopeptides and a solvent with a pH of from about 5 up to but below 7; and
[0232] b) maintaining the pH of the solution at about 5.0 up to but below 7.0 during the admixing by adding hydroxide ions.
[0233] “Tightly” and “loosely” bound calcium and phosphate can be determined using analytical ultrafiltration. Briefly, the solution of phosphopeptide, calcium, phosphate and optionally fluoride admixed while maintaining the pH at about 7.0 or below can be first filtered through a 0.1 micron filter to remove free calcium and phosphate that is not associated with the complexes. This free calcium and phosphate is present in the filtrate and discarded. Any free calcium or phosphate that is not associated in any way with the complexes would not be bioavailable, i.e. delivered by the phosphopeptide to the tooth. The retentate from the 0.1 micron filtration can be further analyzed by centrifugation through a 3000 mw cutoff filter at 1,000 g for 15 min. The resulting filtrate contains calcium and phosphate that is loosely bound or associated with the complexes. At this centrifugal force calcium and phosphate that is not tightly bound to the complexes are released and move into the filtrate. The Ca and Pi that is tightly bound in the complexes is retained in the retentate. The amount of tightly bound Ca and Pi in the retentate can then be determined by subtracting the amount of Ca and Pi in the filtrate from the total amount of Ca and Pi in the retentate of the 0.1 micron filtration.
[0234] A stabilized-ACP or ACFP complex as referred to herein include a stabilized-ACP or ACFP complex as described in WO2006/135982 (PCT/AU2006/000885) the contents of which are incorporated by reference.
[0235] A “superloaded” phosphopeptide or phosphoprotein (PP) stabilized-amorphous calcium phosphate (ACP) or amorphous calcium fluoride phosphate (ACFP) complex.
[0236] The complex may be formed at any pH (e.g. 3-10). Preferably the phosphopeptide includes the sequence -A-B-C-, where A is a phosphoamino acid, preferably phosphoserine, B is any amino acid including a phosphoamino acid and C is glutamic acid, aspartic acid or a phosphoamino acid. The phosphoamino acid may be phosphoserine. The PP is superloaded with calcium and phosphate ions. The calcium ions may be in the range 30-1000 mole Ca per mole of PP, or in the range of 30-100 or 30-50 mole Ca per mole of PP. In another embodiment, the mole Ca per mole of PP is at least 25, 30, 35, 40, 45 or 50.
[0237] The present invention includes a phosphopeptide or phosphoprotein (PP) stabilized amorphous calcium phosphate or amorphous calcium fluoride phosphate complex having a calcium ion content greater than about 30 moles of calcium per mole of PP. In a preferred embodiment, the calcium ion content is in the range of about 30 to 100 moles of calcium per mole of PP. More preferably, the calcium ion content is in the range of about 30 to about 50 moles of calcium per mole of PP.
[0238] The invention also provides a phosphopeptide or phosphoprotein (PP) stabilized-amorphous calcium phosphate (ACP) or amorphous calcium fluoride phosphate (ACFP) complex produced by a method comprising the steps of:
(i) obtaining solutions comprising calcium, inorganic phosphate and fluoride (optional); and
(ii) admixing (i) with a solution comprising PP-ACP.
[0239] In a preferred embodiment, the PP is casein phosphopeptide (CPP).
[0240] In a further aspect, the present invention also includes use of a formulation of a PP stabilized ACP and/or ACFP complex together with at least an equal amount by weight of calcium phosphate. Preferably, the calcium phosphate is CaHPO4 or calcium lactate or any other soluble calcium phosphate compound. Preferably, the calcium phosphate (e.g. CaHPO.sub.4) is dry blended with the PP stabilized ACP and/or ACFP complex. In a preferred embodiment, the PP-ACP and/or PP-ACFP complex: calcium phosphate ratio is about 1:1-50, more preferably about 1:1-25, more preferably about 1:5-15. In one embodiment, the PP-ACP and/or PP-ACFP complex: calcium phosphate ratio is about 1:10.
[0241] The oral care formulation that includes a phosphopeptide or phosphoprotein (PP) stabilized amorphous calcium phosphate (ACP) and/or amorphous calcium fluoride phosphate (ACFP) complex having a calcium ion content greater than about 30 moles of calcium per mole of PP when used in the oral cavity may be produced by a method including the steps of:
(i) obtaining a powder including a PP-ACP and/or PP-ACFP complex;
(ii) dry blending with an effective amount of calcium phosphate; and
(iii) formulating the dry blended PP-ACP and/or PP-ACFP and calcium phosphate mixture into an oral care formulation.
[0242] Preferably, the form of calcium phosphate for dry blending is any soluble calcium phosphate including, but not limited to, CaHPO.sub.4, Ca.sub.2HPO.sub.4 and calcium lactate.
[0243] A composition as described herein may further include free fluoride ions. The fluoride ions may be from any suitable source. A source of fluoride ions may include free fluoride ions or fluoride salts. Examples of sources of fluoride ions include, but are not limited to the following: sodium fluoride, sodium monofluorophosphate, stannous fluoride, sodium silicofluoride and amine fluoride. These may be provided in solution (typically an aqueous solution), or a suspension.
[0244] The fluoride ions are preferably present in the composition in an amount greater than 1 ppm. More preferably, the amount is more than 3 ppm. In another embodiment, it is preferably more than 10 ppm. In typical embodiments described below, the amount may be several hundred or thousand ppm. The fluoride content is typically measured as a ppm in oral compositions in the manner commonly used in the art. Where the fluoride is provided from a source with the stabilized ACP, the ppm refers to the concentration of the fluoride in that source, typically a solution or suspension of bioavailable fluoride.
[0245] A stannous-associated ACP or ACFP complex as referred to herein include any described in PCT/AU2014/050447, the entire contents of which are incorporated by reference in its entirety.
[0246] A composition as described herein for use in a method of use of the invention may include a stannous-associated ACP or ACFP complex. The composition may include 2% CPP-ACP and 290 ppm fluoride with 220 ppm fluoride as stannous fluoride and 70 ppm as sodium fluoride.
[0247] In any aspect or embodiments as described herein, the stabilized ACP and/or ACFP is phosphopeptide (PP)-stabilized. Preferably, the phosphopeptide (as defined below) is a casein phosphopeptide. Preferably, the ACP or ACFP is in the form of a casein phosphopeptide stabilized ACP or ACFP complex.
[0248] “Phosphopeptide” in the context of the description of this invention means an amino acid sequence in which at least one amino acid is phosphorylated. Preferably, the phosphopeptide includes one or more of the amino acid sequence -A-B-C-, where A is a phosphoamino residue, B is any amino acyl residue including a phosphoamino residue and C is selected from a glutamyl, aspartyl or phosphoamino residue. Any of the phosphoamino residues may independently be a phosphoseryl residue. B is desirably a residue the side-chain of which is neither relatively large nor hydrophobic. It may be Gly, Ala, Val, Met, Leu, Ile, Ser, Thr, Cys, Asp, Glu, Asn, Gln or Lys. Preferably, at least two of the phosphoamino acids in the sequence are preferably contiguous. Preferably, the phosphopeptide includes the sequence A-B-C-D-E, where A, B, C, D and E are independently phosphoserine, phosphothreonine, phosphotyrosine, phosphohistidine, glutamic acid or aspartic acid, and at least two, preferably three, of the A, B, C, D and E are a phosphoamino acid. In a preferred embodiment, the phosphoamino acid residues are phosphoserine, most preferably three contiguous phosphoserine residues. It is also preferred that D and E are independently glutamic or aspartic acid.
[0249] In one embodiment, the ACP or ACFP is stabilized by a casein phosphopeptide (CPP), which is in the form of intact casein or fragment of the casein, and the complex formed preferably has the formula [CPP(ACP).sub.8].sub.n or [(CPP)(ACFP).sub.8].sub.n where n is equal to or greater than 1, for example 6. The complex formed may be a colloidal complex, where the core particles aggregate to form large (e.g. 100 nm) colloidal particles suspended in water. Thus, the PP can be a casein protein or a phosphopeptide.
[0250] The PP may be from any source; it may be present in the context of a larger polypeptide, including a full length casein polypeptide, or it may be isolated by tryptic or other enzymatic or chemical digestion of casein, or other phosphoamino acid rich proteins such as phosphitin, or by chemical or recombinant synthesis, provided that it comprises the sequence -A-B-C- or A-B-C-D-E as described above. The sequence flanking this core sequence may be any sequence. However, those flanking sequences in α.sub.s1(59-79), β(1-25), α.sub.s2(46-70) and α.sub.s2(1-21) are preferred. The flanking sequences may optionally be modified by deletion, addition or conservative substitution of one or more residues. The amino acid composition and sequence of the flanking region are not critical.
[0251] The phosphopeptide may be selected from any described in WO2006/056013, WO2006/135982 or U.S. Pat. No. 5,015,628.
[0252] Examples of conservative substitutions are shown in Table 1 below.
TABLE-US-00001 TABLE 1 Original Exemplary Conservative Preferred Conservative Residue Substitution Substitution Ala Val, Leu, Ile Val Asn Gln Lys His Phe Gln Gln Asn Asn Gly Pro Pro Ile Leu, Val, Met, Ala, Phe Leu Leu Ile, Val, Met, Ala, Phe Ile Lys Arg, Gln, Asn Arg Phe Leu, Val, Ile, Ala Leu Pro Gly Gly Ser Thr Thr Val Ile, Leu, Met, Phe, Ala Leu Asp Glu Glu Thr Ser Ser Trp Tyr Tyr Tyr Trp Phe Thr Ser Phe
[0253] The flanking sequences may also include non-naturally occurring amino acid residues. Commonly encountered amino acids which are not encoded by the genetic code, include:
[0254] 2-amino adipic acid (Aad) for Glu and Asp;
[0255] 2-aminopimelic acid (Apm) for Glu and Asp;
[0256] 2-aminobutyric (Abu) acid for Met, Leu, and other aliphatic amino acids;
[0257] 2-aminoheptanoic acid (Ahe) for Met, Leu and other aliphatic amino acids;
[0258] 2-aminoisobutyric acid (Aib) for Gly;
[0259] cyclohexylalanine (Cha) for Val, and Leu and Ile;
[0260] homoarginine (Har) for Arg and Lys;
[0261] 2, 3-diaminopropionic acid (Dpr) for Lys, Arg and His;
[0262] N-ethylglycine (EtGly) for Gly, Pro, and Ala;
[0263] N-ethylasparigine (EtAsn) for Asn, and Gln;
[0264] Hydroxyllysine (Hyl) for Lys;
[0265] allohydroxyllysine (AHyl) for Lys;
[0266] 3-(and 4) hydroxyproline (3Hyp, 4Hyp) for Pro, Ser, and Thr;
[0267] alloisoleucine (Alle) for Ile, Leu, and Val;
[0268] ρ-amidinophenylalanine for Ala;
[0269] N-methylglycine (MeGly, sarcosine) for Gly, Pro, Ala.
[0270] N-methylisoleucine (Melle) for Ile;
[0271] Norvaline (Nva) for Met and other aliphatic amino acids;
[0272] Norleucine (Nle) for Met and other aliphatic amino acids;
[0273] Ornithine (Orn) for Lys, Arg and His;
[0274] Citrulline (Cit) and methionine sulfoxide (MSO) for Thr, Asn and Gln;
[0275] N-methylphenylalanine (MePhe), trimethylphenylalanine, halo (F, CI, Br and I) phenylalanine, triflourylphenylalanine, for Phe.
[0276] In one embodiment, the PP is one or more phosphopeptides selected from the group consisting of α.sub.s1(59-79) [1], β(1-25) [2], α.sub.s2(46-70) [3] and α.sub.s2(1-21) [4]:
TABLE-US-00002 (SEQ ID NO: 1) [1] Gln.sup.59-Met-Glu-Ala-Glu-Ser(P)-Ile-Ser(P)- Ser(P)-Ser(P)-Glu-Glu-Ile-Val- Pro-Asn-Ser(P)-Val-Glu-Gln-Lys.sup.79 α.sub.s1(59-79) (SEQ ID NO: 2) [2] Arg.sup.l-Glu-Leu-Glu-Glu-Leu-Asn-Val- Pro-Gly-Glu-Ile-Val-Glu-Ser(P)-Leu- Ser(P)-Ser(P)-Ser(P)-Glu-Glu-Ser- Ile-Thr-Arg.sup.25 β(1-25) (SEQ ID NO: 3) [3] Asn.sup.46-Ala-Asn-Glu-Glu-Glu-Tyr-Ser-Ile- Gly-Ser(P)-Ser(P)-Ser(P)-Glu-Glu- Ser(P)-Ala-Glu-Val-Ala-Thr-Glu-Glu- Val-Lys.sup.70 α.sub.s2(46-70) (SEQ ID NO: 4) [4] Lys.sup.1-Asn-Thr-Met-Glu-His-Val-Ser(P)- Ser(P)-Ser(P)-Glu-Glu-Ser-Ile-Ile- Ser(P)-Gln-Glu-Thr-Tyr-Lys.sup.21 α.sub.s2(1-21).
[0277] In certain preferred forms of the invention a liquid composition may be a mouthwash, rinse or spray. In such a preparation the vehicle is typically a water-alcohol mixture desirably including a humectant. Generally, the weight ratio of water to alcohol is in the range of from about 1:1 to about 20:1. The total amount of water-alcohol mixture in this type of preparation is typically in the range of from about 70 to about 99.9% by weight of the preparation. The alcohol is typically ethanol or isopropanol. Ethanol is preferred.
[0278] It will be understood that, as is conventional, the oral preparations will usually be sold or otherwise distributed in suitable labelled packages. Thus, a jar of mouth rinse will have a label describing it, in substance, as a mouth rinse or mouthwash and having directions for its use.
[0279] Prior to addition of the liquid composition the dental surface, subsurface or lesion may be prepared (e.g. cleaned) using preparative compositions. Such compositions may include the following components. Organic surface-active agents may be used in the compositions to achieve increased prophylactic action, assist in achieving thorough and complete dispersion of the active agent throughout the oral cavity, and render the instant compositions more cosmetically acceptable. The organic surface-active material is preferably anionic, non-ionic or ampholytic in nature and preferably does not interact with the active agent. It is preferred to employ as the surface-active agent a detersive material which imparts to the composition detersive and foaming properties. Suitable examples of anionic surfactants are water-soluble salts of higher fatty acid monoglyceride monosulfates, such as the sodium salt of the monosulfated monoglyceride of hydrogenated coconut oil fatty acids, higher alkyl sulfates such as sodium lauryl sulfate, alkyl aryl sulfonates such as sodium dodecyl benzene sulfonate, higher alkylsulfo-acetates, higher fatty acid esters of 1,2-dihydroxy propane sulfonate, and the substantially saturated higher aliphatic acyl amides of lower aliphatic amino carboxylic acid compounds, such as those having 12 to 16 carbons in the fatty acid, alkyl or acyl radicals, and the like. Examples of the last mentioned amides are N-lauroyl sarcosine, and the sodium, potassium, and ethanolamine salts of N-lauroyl, N-myristoyl, or N-palmitoyl sarcosine which should be substantially free from soap or similar higher fatty acid material. The use of these sarconite compounds in the oral compositions of the present invention is particularly advantageous since these materials exhibit a prolonged marked effect in the inhibition of acid formation in the oral cavity due to carbohydrate breakdown in addition to exerting some reduction in the solubility of tooth enamel in acid solutions. Examples of water-soluble non-ionic surfactants suitable for use are condensation products of ethylene oxide with various reactive hydrogen-containing compounds reactive therewith having long hydrophobic chains (e.g. aliphatic chains of about 12 to 20 carbon atoms), which condensation products (“ethoxamers”) contain hydrophilic polyoxyethylene moieties, such as condensation products of poly (ethylene oxide) with fatty acids, fatty alcohols, fatty amides, polyhydric alcohols (e.g. sorbitan monostearate) and polypropyleneoxide (e.g. Pluronic materials).
[0280] Various other materials may be incorporated in the oral preparations of this invention such as whitening agents, preservatives, silicones, chlorophyll compounds and/or ammoniated material such as urea, diammonium phosphate, and mixtures thereof. These adjuvants, where present, are incorporated in the preparations in amounts which do not substantially adversely affect the properties and characteristics desired. Any suitable flavouring or sweetening material may also be employed. Examples of suitable flavouring constituents are flavouring oils, e.g. oil of spearmint, peppermint, wintergreen, sassafras, clove, sage, eucalyptus, marjoram, cinnamon, lemon, and orange, and methyl salicylate. Suitable sweetening agents include sucrose, lactose, maltose, sorbitol, xylitol, sodium cyclamate, perillartine, AMP (aspartyl phenyl alanine, methyl ester), saccharine, and the like. Suitably, flavour and sweetening agents may each or together comprise from about 0.1% to 5% more of the preparation.
[0281] The further composition of alkaline pH may further comprise additional components to enhance gel formation. For example the addition of stannous, zinc, magnesium or other metal ions or other chemicals which help cross-link the phosphopeptide-stabilized ACP or ACFP to enhance gelation.
[0282] It will be clearly understood that, although this specification refers specifically to applications in humans, the invention is also useful for veterinary purposes. Thus in all aspects the invention is useful for domestic animals such as cattle, sheep, horses and poultry; for companion animals such as cats and dogs; and for zoo animals.
[0283] The invention will now be further described with reference to the following non-limiting examples.
EXAMPLE 1
Preparation of High Concentration Liquid CPP-ACFP and CPP-ACP Solutions
[0284] Stock solutions of 3.25 M CaCl.sub.2 and 1.25 M NaH.sub.2PO.sub.4 (pH 5.5) were added in approximately thirty aliquots to a 10-15% w/v tryptic digest of casein until just before precipitation or gelation (usually producing a final concentration of approximately 78 mM to 124 Ca.sup.2+ and 48 to 76 mM inorganic phosphate). The solutions were added slowly (that is, less than approximately 1% volume addition per minute) with adequate mixing. An aliquot of the phosphate solution was added first, followed by an aliquot of the calcium solution. The bulk solution pH was maintained at 9.0 using 1 to 10 M NaOH with thorough mixing. The sodium hydroxide solution was added automatically by a pH stat with the addition of the hydroxide ions usually being after each addition of the calcium ions. After completion of the addition of the calcium ions, phosphate ions and hydroxide ions the solution was filtered through a 0.1 micron filter to concentrate 1-2 fold. The retentate was then washed with 1-2 volumes of water to remove salts and inactive (and bitter tasting) peptides. The CPP-ACP solutions prepared were then spray dried or freeze dried to produce a white powder. This dried powder was then added to water to form a 45% w/v CPP-ACP solution at pH 5.5 by addition of 1-10 M HCl or a 63% w/v CPP-ACP solution with added NaF to produce 8,200 ppm F at pH 5.5 by addition of 1-10 M HCl.
[0285] The 75% w/v solution was prepared by adding 75 g CPP-ACP powder to 20 ml water with a small amount of powder each addition (0.5 g/min) while maintaining the pH at 5.5 by the addition of 10 M HCl. The solution was thoroughly mixed after each addition to ensure dispersion. A concentrated NaF (0.95 M) solution was added together with 10 M HCl to ensure that 52 mmol of F was finally added. The CPP-ACP powder, NaF and HCl were added over 2-3 hours with water to a final volume of 100 ml. This produced a liquid composition of 75% w/v CPP-ACP, 9,880 ppm F at pH 5.5.
EXAMPLE 2
Masking a White Spot Lesion Using CPP-ACP and Alkaline Solution
[0286] A 45% w/v CPP-ACP pH 5.5 liquid solution was applied with a microbrush (for a few seconds) to the surface of an enamel block with a white spot lesion. The enamel block was then incubated for 20 minutes at 37° C. Then a 1 M NaOH solution (about pH 14) was applied with a microbrush (for a few seconds) and the enamel block was then incubated at 37° C. for a further 20 minutes.
[0287]
[0288] The white spot lesions in the treatment sample were substantially masked by the treatment by returning the lesion translucent compared to the control sample where the white spot lesions are still clearly visible.
EXAMPLE 3
Masking a White Spot Lesion Using 63% w/v CPP-ACP, Free Fluoride and Alkaline Solution
[0289] A 63% w/v CPP-ACP and 8,200 ppm F as NaF pH 5.5 liquid solution was applied with a microbrush (for a few seconds) to the surface of an enamel block with a white spot lesion. The enamel block was then incubated for 20 minutes at 37° C. Then a 1 M NaOH solution was applied with a microbrush (for a few seconds) and the enamel block was then incubated at 37° C. for a further 20 minutes.
[0290]
EXAMPLE 4
[0291] In a dental clinic, a patient in need of a reduction in the visibility of a hypomineralised dental surface or subsurface of the tooth enamel may be treated using the steps of:
1. Apply rub dam and acid etch the white spot [this step is optional and not necessary for very porous (active) lesions]. This can involve standard liquid rubber dams (resin barrier to protect soft tissue) and acid etching techniques (e.g. 30% phosphoric acid or 15% HCl).
2. Apply high concentration (>40% w/v) stabilised CPP-ACP or CPP-ACP/F acid solutions (e.g. less than pH 6) to white spots using a microbrush and then leave for 5-20 min. Heat can be optionally applied by using a high intensity LED curing light (e.g. 1 Ow high power blue light) to increase temperature in bursts to 45-50° C. (with patient comfort).
3. Apply high concentration base (e.g. 4% w/v NaOH) using a microbrush and then leave for 5-20 min. Heat can be optionally applied by using a high intensity LED curing light (e.g. 10W high power blue light) to increase temperature in bursts to 45-50° C. (with patient comfort).
EXAMPLE 5
Exemplary Dental Kit
[0292] A dental kit comprising or consisting of three parts:
[0293] (a) 5 g of a CPP-ACP powder, preferably prepared as described herein,
[0294] (b) 5 ml of 0.73 M NaF in 1.146 M HCl, and
[0295] (c) 1.5 M NaOH, including two microbrushes.
[0296] Part (a) was added to part (b) with thorough mixing. This mixture was then applied with one microbrush to the white spot lesions on the left (see image in
EXAMPLE 6
Masking a White Spot Lesion Using 75% w/v CPP-ACP, Free Fluoride and Alkaline Solution
[0297] A 75% w/v CPP-ACP and 9,880 ppm F as NaF pH 5.5 liquid was applied with a microbrush (for a few seconds) to the surface of an enamel block with a white spot lesion. The enamel block was then incubated for 10 minutes at 37° C. Then a 2M NaOH solution was applied with a microbrush (for a few seconds) and the enamel block was then incubated at 37° C. for a further 20 minutes.
[0298]
EXAMPLE 7
Masking a White Spot Lesion by Forming Mixed Composition Prior to Application to the Dental Surface
[0299] A liquid composition of a degassed 63% w/v CPP-ACP/ 8,000 ppm F at pH 5.5 was mixed with a solution of 1.5 M NaOH prior to application to a dental surface. The mixed composition was then painted on to a white spot lesion. A dental curing light on setting 2 was then applied to the surface for 40 secs. The result is an impressive covering of the enamel white spots (
EXAMPLE 8
Formation of a Protective Layer Over Dentine
[0300] Another application of this invention is to seal or occlude exposed tooth root (dentine) surfaces (aging population has exposed root surfaces and they are more susceptible to caries/erosion). To simulate these exposed root surfaces tooth root dentine was treated with 15% EDTA for 2 min thereby removing the smear layer to expose dentinal tubules (
[0301] Further, when the mixed composition was applied to the dentine surface (either sound or prior demineralised with acid buffer) the solution not only gels but also starts to form a fluorapatite (FA) layer on the surface to seal the dentine (shown in
[0302] The protective layer formed was purposefully dehydrated (as shown in
[0303] An elemental analysis revealed that the formed protective layer had a composition similar to fluorohydroxyapaptite (
EXAMPLE 9
Formation of a protective layer over dentine
Metho:
[0304] All dentine blocks were polished
[0305] Dentine block treated with 15% EDTA for 2 min
[0306] 15 second etch (37% phosphoric acid)
[0307] Mix degassed 63% (w/v) CPP-ACP/8,100 ppm F (pH 5.5) with equal volume of 2 M NaOH
[0308] Topical application of pre-mixed 63% (w/v) CPP-ACP/8,100 ppm F (pH 5.5) and 2 M NaOH on dentine surface using microbrush
[0309] 40 second light cure
[0310] Leave at 37° C. for 48 h
[0311] Sectioned, lapped and microradiographed.
As shown in
EXAMPLE 10
Formation of a Protective Layer Over Enamel
Method
[0312] All enamel blocks were polished
[0313] 15 second etch (37% phosphoric acid)
[0314] Mix 63% (w/v) CPP-ACP/8100ppm F (pH 5.5) with equal volume of 2 M NaOH
[0315] Topical application of pre-mixed 63% (w/v) CPP-ACP/8,100 ppm F (pH 5.5) and 2 M NaOH on enamel surface using microbrush
[0316] 40 second light cure
[0317] Leave at 37° C. for 48 h
[0318] Sectioned, lapped and microradiographed.
[0319] As shown in
EXAMPLE 11
Masking a White Spot Lesion by Forming Mixed Composition Prior to Application to the Dental Surface
[0320] 30 g of CPP-ACP powder (commercial Recaldent) was added to 19.5 g of a 20,000 ppm F (NaF) solution to which 0.5 g of an 11 M HCl solution was added to give the final weight 50 g (hence this final solution is a 60% w/w CPP-ACP with 7,800 ppm F at pH 7.8 or 75% w/v CPP-ACP containing 10,000 mg/L F at pH 7.8).
[0321] With thorough stirring (around 30 min) a homogeneous very viscous but stable solution was prepared with a pH of 7.8. This solution was then degassed to remove trapped air bubbles by placing the solution under vacuum for 24 hours.
[0322] The solution was applied to white spot lesions using a microbrush and then light cured for 40 sec using the dental curing light (as described previously). The images of before and after (
[0323] The viscous, stable and safe (neutral pH) solution is easy to apply in the dental surgery and is more concentrated so produces a better effect over a longer period of time.
[0324] 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.