COMPOSITION FOR THE REMINERALIZATION OF TEETH

Abstract

The present invention relates to a composition for the remineralization of teeth and to the use thereof. The composition comprises calcium phosphate (CaP) glass, and aqueous silica sol.

Claims

1. A composition for remineralizing teeth, comprising: a) calcium phosphate (CaP) glass, and b) aqueous silica sol.

2. The composition as claimed in claim 1, wherein the CaP glass is ground and sieved and has a particle size <100 μm.

3. The composition as claimed in claim 2, wherein the particle size of the CaP glass has a D.sub.50<35 μm and/or a D.sub.90<90 μm.

4. The composition as claimed in claim 1, further comprising fully demineralized water and dilute hydrochloric acid.

5. The composition as claimed in claim 1, further comprising chlorhexidine digluconate and/or dilute hydrochloric acid.

6. The composition as claimed in claim 1, wherein the calcium phosphate glass is produced of approximately equimolar amounts of CaCO.sub.3 and P.sub.2O.sub.5.

7. The composition as claimed in claim 1, comprising: approximately SiO.sub.2 sol 30-35% w/w, water 60-70% w/w, and CaP glass 2-3% w/w, based on the total amount of the SiO.sub.2 sol, water and CaP glass constituents.

8. The use of the composition as claimed in claim 1 for remineralizing teeth.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0038] FIG. 1: left) oven charge; right) oven programming.

[0039] FIG. 2: SEM images (magnification 2500) of treated dentin surfaces after 0 d, 1 d, 7 d and 14 d.

[0040] FIG. 3: Dentin surfaces with vertical dentinal tubules before (0 d) and after (14 d) the treatment with the composition of the invention.

[0041] FIG. 4: Topographic SEM image of the untreated (0 d) and treated (14 d) dentin surface.

[0042] FIG. 5: Cross section through dentinal tubuli in a dentin surface treated with the composition of the invention after 14 d (top in the image).

EXAMPLES

1 Production of Calcium Phosphate Glass

1.1 Production of Raw Glass Mixture

[0043] Producing a crucible charge of the calcium phosphate glass requires 101.09 g of CaCO.sub.3 (1.00 mol) and 141.94 g of P.sub.2O.sub.5 (1.00 mol).

[0044] 25.27 g of CaCO.sub.3 (0.250 mol) are weighed out and placed in an agate mortar. Then, using a ceramic spatula, 35.48 g of P.sub.2O.sub.5 (0.250 mol; NB: highly hygroscopic!) are weighed out rapidly and added to the CaCO.sub.3 in the agate mortar.

[0045] The mixture undergoes intimate trituration for 2 minutes. The mixture must then rest for 5 minutes, and is then triturated again for 2 minutes.

[0046] The mixture is introduced into the aluminum oxide crucible, and a further portion is prepared as described above from 25.27 g of CaCO.sub.3 and 35.48 g of P.sub.2O.sub.5, and so on. Owing to the capacity of the agate mortar, larger amounts must not be triturated at once, in order to ensure effective mixing.

1.2 Preparation of the Firing Oven (Glass Melting)

[0047] The oven is charged as shown in FIG. 1. The oven is closed and the sintering program is selected with a heating rate of 0° C.-1050° C.: 300 K/h.

[0048] See FIG. 1: left) oven charging; right) oven programming.

1.3 Glass Casting

[0049] A heat-resistant pail must be provided with cold mains water (not FD water, to prevent leaching of the glass!).

[0050] The crucible is grasped with the tongs (verify secure grip), moved to a short way above the pail (avoid splashing), and the glass melt is poured into the cold water. The operation must be carried out safely but rapidly in order to prevent the glass melt cooling in the crucible.

[0051] Thereafter, the crucible is to be placed back into the ceramic housing in the oven, the oven sealed, and allowed to cool down freely.

[0052] The solidified glass should be removed from the water as soon as possible and dried in a drying cabinet at 40° C. for 16 hours. After that it can be ground.

1.4 Glass Grinding

[0053] The solidified glass should be roughly comminuted and then divided between two aluminum oxide grinding cups. Aluminum oxide grinding beads (3 medium beads d=1.5 cm, 4 small beads, d=1 cm) are added and the glass is ground in the planetary ball mill at 200 rpm for 4 hours. In order to ensure that no relatively large particles are left (there may be glass splinters and relatively large grains!), the ground glass is sieved with a sieve (200 μm) in the sieving tower. For determination of the mean particle size, a sample is taken and subjected to measurement by laser granulometer (D.sub.50<25 μm).

2 Production of the Mixture Components

2.1 Chemicals

[0054] Köstrosol® 0830 (aqueous silica sol, see “Köstrosol 830 data sheet”) [0055] fully demineralized water (FD water), boiled for sterilization [0056] dilute hydrochloric acid (1.62 g of 35% hydrochloric acid to 100 g of FD water) [0057] calcium phosphate glass (ground and sieved; particle size <100 μm, see section 1) [0058] Chlorhexidine digluconate 20% (optional)

2.2 Apparatus

[0059] Sartorius CP324S analytical balance [0060] Brand Transferpette S (volume 500-5000 μl) [0061] Brand Transferpette S (volume 100-1000 μl) [0062] Portamess 911 pH pH meter (from Knick) [0063] 150 ml beakers (for preparing the liquid component) [0064] 1 small rolled-edge glass vessel (for weighing out calcium phosphate glass) [0065] 12 rolled-edge glass vessels (50 mm×20 mm, 15 ml capacity) for the application units [0066] 12 fitting lids [0067] 12 magnetic stirring rods (10×6 mm) [0068] Multipoint stirrer (from. VarioMag)

[0069] Beakers, rolled-edge glass vessels and magnetic stirring rods are sterilized by boiling in fully demineralized water (FD water). The lids are disinfected with Bacillol® (cleaning product based on 2-propanol, 1-propanol and ethanol).

2.3 Preparation of Liquid Component

[0070] 26.8 g of Köstrosol® and 53.2 g of boiled water are weighed out. The two components are then combined and stirred for around 15 minutes.

2.4 Preparation of Suspensions

[0071] For each application unit, 5 g of the liquid component are used. Weighing takes place on the Sartorius CP324S analytical balance. In each case 4710 μl of the liquid component (density: 1.06 g/ml) are pipetted using the Brand Transferpette S (volume 500-5000 μl) into the 12 rolled-edge glass vessels. Subsequently in each case 0.125 g of the solid component (calcium phosphate glass) are weighed out into a small rolled-edge glass vessel on the Sartorius CP324S analytical balance and transferred into the 12 rolled-edge glass vessels containing the liquid component.

[0072] Suspensions are formed by combining liquid and solid components. The rolled-edge glass vessels are sealed with the associated lids. The samples are subsequently stirred on the multipoint stirrer (from VarioMag) at 700-750 rpm for around 1 hour.

2.5 pH Measurement and HCl Addition

[0073] After a stirring time of 1 hour, 300 μl of dilute hydrochloric acid in each case are added using the Brand Transferpette S (volume 100-1000 μl). The 12 rolled-edge glass vessels are then sealed again. The samples are stirred overnight.

2.6 Addition of Chlorhexidine Digluconate (20%)

[0074] Lastly, chlorhexidine digluconate (20%) is added. It is weighed out on the Sartorius CP324S analytical balance. 50 μl of chlorhexidine digluconate (20%) in each case are transferred using the Brand Transferpette S (volume 100-1000 μl) into the 12 samples. The individual weighed amounts are recorded. Following the addition of chlorhexidine digluconate, the samples are sealed again and stirred further for 5 minutes more. A flocky precipitate is formed. On prolonged standing (around 2 hours) the sample become solid.

3 Sealing of Dentinal Tubules in an In Vitro Experiment

3.1 Sample Preparation

[0075] Tooth samples were polished transversely to the dentinal tubules. Remineralization suspension was applied using cotton buds to the cleaned and dried samples. The suspension acted on the tooth (dentin) for 10 minutes. The samples were subsequently stored for defined times (0 d, 1 d, 7 d, 14 d) in saline solution (medium was changed daily). This setup served to simulate the environment in the oral cavity. At the observation times, the samples were removed, dried and analyzed by scanning electron microscopy (SEM).

3.2 Experimental Results

[0076] The SEM images in FIG. 2 show the treated dentin surfaces at the various observation times (0 d, 1 d, 7 d, 14 d).

[0077] See FIG. 2: SEM images (magnification 2500) of treated dentin surfaces after 0 d, 1 d, 7 d and 14d.

[0078] At time 0 d, only roughened enamel is present. Thereafter the bioglass-based remineralizing paste identified in the use example is applied. After 1 d a continuous layer is still perceivable. After 7 d the coating beings to disintegrate, and release of calcium ions and phosphate ions commences. These ions remineralize to form calcium phosphate and seal the dentinal tubules under the coating, by exceeding the solubility product of calcium and phosphate.

[0079] Following complete disintegration of the coating, two effects can be observed (FIGS. 3, 4).

[0080] FIG. 3 shows dentin surfaces with vertical dentinal tubules before (0 d) and after (14 d) the treatment with the composition of the invention. In FIG. 3 it is apparent that the dentinal tubules are completely closed, in comparison to the untreated surface.

[0081] In FIG. 4 it is evident that the unevennesses and defects on the dentin surface have been significantly minimized as a result of the treatment. FIG. 4 shows a topographic SEM image of the untreated (0 d) and treated (14 d) dentin surface.

[0082] When a transverse section relative to the dentinal tubules is prepared (FIG. 5), the sealing of the tubules as a result of the treatment with the bioglass-based remineralizing paste is clearly evident.