the present invention will now be described in detail with reference to a number of examples . fifty ( 50 ) g of hydroxy - apatite finely divided to 10 microns or less to which 50 ml of water was added was treated in a chaser mill to obtain a paste . shortly after the teeth were brushed with a dentifrcce followed by rinsing , the paste was carefully rubbed on the surface of the teeth with a fingertip for 3 min . afterwards , excess paste was removed from within the mouth by light rinsing this procedure was carried out whenever teeth were brushed . fifty ( 50 ) g of hydroxy - apatite finely divided to 10 microns or less to which 50 ml of an aqueous solution containing 500 ppm of sodium fluoride was added was treated in a chaser mill to obtain a paste . at the completion of ordinary brushing , teeth were brushed for 3 min with a toothbrush to which paste was applied . this was followed by light rinsing . this brushing was always carried out after ordinary brushing . fifty ( 50 ) g of hydroxy - apatite finely divided to 10 microns or less to which 50 ml of water containing 0 . 01 mg of casein was added was treated in a chaser mill to obtain a paste . at the completion of ordinary brushing , the paste was carefully rubbed on the surface of the teeth with a fingertip for 3 min . this procedure was carried out whenever teeth were brushed . in a manner similar to that described in example 3 , the paste was rubbed on the surface of teeth and excess paste within the mouth was then washed away by rinsing . following drying , a nuva - seal liquid was thinly applied to the surface of the teeth and was hardened by an ultraviolet lamp for sealing purposes . in a manner similar to that described in example 3 , the paste was rubbed on the surface of teeth and excess paste within the mouth was then washed away by rinsing . diamine silver fluoride was applied in the conventional manner . four ( 4 ) g of hydroxy - apatite finely divided to 10 microns or less and 0 . 04 mg of casein were added to and mixed sufficiently with 100 ml of vinyl acetate to prepare a homo - geneous dispersion . after ordinary brushing , the teeth were dried with warm air and then uniformly coated with the dispersion by means of a brush . drying gave a glossy , white and fine coating on the surface of the teeth . fifty ( 50 ) g of tetracalcium phosphate finely divided to 10 microns or less to which 50 ml of water was added was treated in a chaser mill to obtain a paste . shortly after teeth were brushed with a dentifrice followed by thorough rinsing , the paste was carefully rubbed on the surface of the teeth with a fingertip for 3 min . afterwards , excess paste was removed from within the mouth by light rinsing . this procedure was carried out whenever teeth were brushed . fifty ( 50 ) g of tetracalcium phosphate finely divided to 10 microns or less to which 50 ml of an aqueous solution containing 500 ppm of sodium fluoride was added was treated in a chaser mill to obtain a paste . at the completion of ordinary brushing , teeth were brushed for 3 min with a toothbrush to which the paste was applied . this was followed by light rinsing . this brushing was always carried out after ordinary brushing . fifty ( 50 ) g of tetracalcium phosphate finely divided to 10 microns or less to which 50 ml of water containing 0 . 01 mg of casein was added was treated in a chaser mill to obtain a paste . at the completion of ordinary brushing , the paste was carefully rubbed on the surface of the teeth with a fingertip for 3 min . this procedure was carried out whenever teeth were brushed . in a manner similar to that described in example 3 , the paste was rubbed on the surface of teeth and excess paste within the mouth was then washed away by rinsing . following drying , a nuva - seal liquid was thinly applied to the surface of the teeth and was hardened by an ultraviolet lamp for sealing purposes . four ( 4 ) g of tetracalcium phosphate finely divided to 10 microns of less and 0 . 04 mg of casein were added to and mixed sufficiently with 100 ml of vinyl acetate to prepare a homogeneous dispersion . after ordinary brushing , the teeth were dried with warm air and then uniformly coated with the dispersion by means of a brush . drying gave a glossy , white and fine coating on the surface of the teeth . in order to measure the amount of hydroxy - apatite bonded to the surface of a tooth , the following in vitro tests were conducted : one hundred ( 100 ) ml of a 0 . 1 m cacl 2 solution ( containing 45 cacl 2 manufactured by aeroham ) was slowly added dropwise , under agitation , to 100 to 200 ml of 0 . 1m na 2 hpo 4 solutions to synthesize hydroxy - apatite in the conventional manner . on the other hand , a 0 . 1m 45 cacl 2 solution was similarly added dropwise to 100 to 200 ml of 0 . 01 nah 2 hpo 4 solutions to prepare brassid . after preparation , the hydroxy - apatite and brassid were preserved in the corresponding 0 . 1 m na 2 hpo 4 and 0 . 1 m nah 2 po 4 solutions . for use , they were resuspended in 0 . 01 m phosphoric acid buffers of the corresponding ph . the hydroxy - apatite was molded into a disc which was 1 cm in diameter and 3 mm in thickness , and the disc was sintered to form a hydroxy - apatite tablet , the surface of which was evenly abraded with no . 600 sand paper . afterwards , the tablet was brushed to carefully remove powders , while distilled water flowed thereover , thereby making an artificial tooth . ( c ) an acryl tank which was 12 cm in length , 4 cm in width and 10 mm in depth was provided in its bottom with five blind holes for the fixation of hydroxy - apatite tablets , each of which was 1 cm in diameter and 2 mm in depth . five hydroxy - apatite tables were fixed in the blind holes and 5 ml of a hydroxy - apatite or brassid suspension was added to immerse the tablets . the upper surface of the tablets was abraded at 1 rpm . upon elapse of a certain time , the tablets were removed and , soon thereafter , washed by dropwise addition of a large amount of distilled water . two ( 2 ) ml of a psc cocktail was added to the tablets to measure the radioactivity of the tablets with a liquid scintillation counter . as the results of tests performed at ph 9 . 0 and 5 . 0 that were the stable ph of hydroxy - apatite and brassid , respectively , the amount of hydroxy - apatite bonded to the tablets was 5 micrograms after 5 min . thereafter , this increased gradually and reached 164 micrograms after 40 min , as calculated from 5 . 4 × 10 5 cpm / mg and 8 . 9 × 10 5 cpm / mg that where the specific radioactivities of the hydroxy - apatite and brassid used , respectively . this bonded amount was much larger than that of brassid by a factor of 20 after 5 min and 109 after 40 min . from the results of tests performed at ph 5 . 5 , 6 . 8 , 7 . 4 and 8 . 5 , where rubbing was carried out at the same ph , it was also found that the bonding force of hydroxy - apatite to the tablets was markedly increased . these results are tabulated below . ______________________________________ a / bph condition after 10 min after 60 min______________________________________a : ph 9 , b : ph 5 32 . 8 201 . 7a , b ph 8 . 5 2 . 0 5 . 4a , b ph 7 . 4 6 . 6 5 . 4a , b ph 6 . 8 2 . 3 6 . 4a , b ph 5 . 5 11 . 2 8 . 4______________________________________ a : hydroxyapatite ; b : brassid figures represent the amounts in weight ratio of hydroxyapatite and tetracalcium phosphate bonded to the tablets . these results reveal that hydroxy - apatite is selectively bonded to the surface of teeth . thus , according to the method of the present invention , a fine filler containing hydroxy - apatite that is a biomaterial firmly bonding to the pits and fissures or minute decalcified lesions in the surfaces of teeth or tetracalcium phosphate with or without adjuvants is rubbed on the surface of teeth , optionally followed by covering the thus rubbed site with a polymer , to cover the pits and fissures or decalcified lesions with the fine filler , so that spontaneous healing power is augmented under the action of saliva or the adjuvants for the restoration of the decalcified lesions . this method exhibits excellent effects merely by rubbing the fine filler on the surface of teeth . since hydroxy - apatite or tetracalcium phosphate is the most ideal calcium substance , it is harmless if swallowed and the filler can be used without fear of harmful effects . no special clinical skill is required to carry out this method . accordingly , the method of the invention is advantageous in that it can easily be carried out by the patient himself . the present method in which caries is suppressed in its incipient stage by making use of , and augmenting , spontaneous healing power obtained through recalcification by saliva is the most effective means for preventing caries that is not found in the prior art . the present invention is also applicable to the treatment of paresthesia and pyrrhoea alveolaris .
a fine filling method for dental purposes is characterized in that a fine filler in the form of a powder , a granulate , a suspension or paste , containing finely divided particles of hydroxy - apatite or tetracalcium phosphate , with or without an adjuvant , is rubbed on the surface of a tooth and contacted with saliva . the fine filler for use in this method may contain a calcification - promoting protein .