) V o l. 40 N o. 1 : O : A. (Ca3 (PO 4) 2 [ TCP ] CaH PO 4 2H 2O [DCPD ] Ca8H 2 (PO 4) 6 5H 2O [OCP ] ) (Ca10 (PO 4) 6 (OH ) 2 [HA P ]) .

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1 40 1 ( ) V o l 40 N o Jou rnal of X iam en U n iversity (N atu ral Science) Jan 2001 : (2001) ,, (,, ) : (HA P),, (DCPD ) XRD SEM, 37 DCPD N af ph, HA P ph DCPD HA P, DCPD N af : (DCPA ) DCPA + (FA P) FA P FA P+ CaF 2 ph, : ; ; ; ph : O : A (Ca10 (PO 4) 6 (OH ) 2 [HA P ]) (Ca3 (PO 4) 2 [ TCP ] CaH PO 4 2H 2O [DCPD ] Ca8H 2 (PO 4) 6 5H 2O [OCP ] ),,,,, HA P [ 1 5,, HA P ] DCPD HA P, [ 6 ], DCPD [ 7 ],, 37 DCPD, HA P : : ( ), (E ) : (1976- ),, :,,

2 1 : 53 1 DCPD HA P ( 260 ) N af ( , , , m o l L - 1 ) 1 0 gg50 ml, 37,, ph 2206 ph,,, N af ( , , , , , m o l L - 1, 1 DCPD mo l L - 1 ), : N af ph E = (- lg [F - ]) (P < F ig 1 H ydro lysis of DCPD in , : mo l L - 1 N af so lutions m o l L - 1 ) R igaku Ro taflex D gm ax2c X H itach i S2520 DCPD HA P m o l L - 1 N af 10 h 0 1 m o l L - 1 KNO 3 ( 0 1 m o l L - 1 HNO 3 ph 6 00), 0 1 m o l L - 1 HNO 3, ( ZD 22A D Z21 ) ph ph, 2 DCPD N af ph 10 h X ph,,, m o l L DCPD mo l L - 1 N af 10 h, m o l L - 1, ph XRD, XRD F ig 2 XRD patterns of the hydro lysate of, N af DCPD obtained after 10 hours hy2, dro lysis in mo l : (DCPA ) DCPA + L - 1 N af so lutions (FA P) FA P FA P + CaF , DCPD N af 10 h

3 54 ( ) 2001,, 0, 100% F - 3 DCPD m o l L - 1 N af SEM,DCPD,, 3 DCPD mo l L - 1 N af 4 HA P 5-10 h ( 2 100) F ig 3 M o rpho logy of hydro lysate of DCPD obtained after 10 hours hydro lysis in mo l L - 1 N af so lutions at 37 ( 2 100) mo l L - 1 N af ph F ig 4 HA P hydro lysis in mo l L - 1 N af so lutions 1 DCPD N af 10 h F - (37 ) T ab 1 T he fluo ride ion concentration and the amount of F up take after DCPD w as hydro lyzed in ppm N af so lutions at 37 F - g 10-6 mo l L F - gmo lgl gm g L - 1 DCPD , F - ( mo lgl ) 3 3 HA P ph 4, ph, 0 25 m o l L HA P m o l L - 1 N af 10 h XRD 5,, CaF 2 6 DCPD, HA P m o l L - 1 N af 10 h

4 1 : 55 5 HA P mo l L - 1 N af 6 DCPD HA P mo l L h XRD F ig 5 XRD pattern of hydro lysate of HA P ob2 tained after 10 hours hydro lysis mo l L - 1 N af so lution in N af 10 h F ig 6 Curve fo r the disso lution of DCPD, HA P and their hydro lysate ob tained after 10 hours hydro lysis in mo l L - 1 N af so lution,, DCPD HA P CaF 2, DCPD, F - DCPD, DCPD,, DCPD (F m o l L - 1 ), DCPD DCPA (CaH PO 4) + FA P: 15CaH PO 4 2H 2O + 2F - Ca10 (PO 4) 6F 2+ 5CaH PO 4+ 2H 2PO H 3PO 4+ 30H 2O DCPD, Ca 2+, H 3PO 4 FA P, ph, XRD FA P,DCPD, H 3PO 4, ph 1, ( m o l L - 1 ), 0, F -, Ca 2+ PO 3-4 DCPD,,, F - DCPD,, F m o l L - 1,DCPD FA P: 10CaH PO 4 2H 2O + 2F - Ca10 (PO 4) 6F 2+ 2H 2PO H 3PO 4+ 20H 2O ph,dcpd,, 0 25 m o l L - 1, F -, F - CaF 2: 13CaH PO 4 2H 2O + 8F - Ca10 (PO 4) 6F 2+ 6H 2PO CaF 2+ H 2PO H 2O

5 56 ( ) 2001 ph m o l L - 1 ( 1),, DCPD, Ca 2+ PO 3-4 FA P CaF 2, DCPD ( 3) DCPD, (F - ), [ 8, ],, HA P 4, ph F -, HA P : Ca10 (PO 4) 6 (OH ) 2+ XF - Ca10 (PO 4) 6FX (OH ) 2- X+ XOH - F -,, ph, HA P,, CaF 2 ( 5), HA P, ph HA P F - OH - DCPD,,, ph ( ), HA P ;, F DCPD,,,,, ph, ph, N anco llas ph [ 9, 10 ], ph ph, ph,, ph, ph, HNO 3 H +, ( 6), DCPD m o l L - 1 N af DCPD HA P,, DCPD, DCPD FA P HA P HA P,OH - c F - OH - (rf - = nm, roh - = 0 16 nm ), F - OH -, HA P FA P FHA P,, 2, U = AN Z1Z2E 2g4ΠΕ0r1,,,, F - OH -, FA P [ 11, 12 HA P,, ] (K SPFA P= , K SPFA P = ) DCPD FA P, DCPD, HA P m o l L - 1 N af FA P CaF 2, HA P (K SPCaF 2 = , K SPHA P= ) [ 13 ], DCPD

6 1 : 57 4 (1) DCPD,,, DCPA + FA P FA P FA P+ CaF 2 CaF 2, ph HA P ph, (2) DCPD HA P, CaF 2 (3),, DCPD : [ 1 ] M o reno E C, K resak M, Zah radnik R T F luo ridated hydroxyapatite so lubility and caries fo rm ation [J ] N atu re, 1974, 247: [ 2 ] T anizaw a Y, T duch ikane M, Saw am ura K, et al R eaction characteristics of hydroxyapatite F - w ith PO 3F 2- and ions (Chem ical states of fluo rine in hydroxyapatite) [J ] J Chem Soc Faraday T ranṡ, 1991, 97 (14): [ 3 ] T anizaw a Y, Suzuk i T X2R ay pho toelectron spectro scopy study on chem ical states of fluo ride in bovine dentine treated w ith N af [J ] J Chem Soc Faraday T ranṡ, 1993, 89(15): [4 ] V an den Hoek W G M, Feenstra T P, D e B ruyn P L Influence of fluo ride on the fo rm ation of calcium pho sphates in m oderately supersatu rated so lu tion s[j ] J Phyṡ Chem, 1980, 84: [5 ] N arasaraju T S B, Phebe D E Som e physico2chem ical aspects of hydroxylapatite[j ] J M ateṙ Sci, 1996, 31: 2-21 [6 ] Glim cher M J, Bonar L C, GrynpasM D, et al R ecent studies of bone m ineral: Is the amo rphous cal2 cium pho sphate theo ry valid[j ] J C rystal Grow th, 1981, 53: [ 7 ] Zhang J, N anco llas G H Interaction of disso lution k inectics of dicalcium pho sphate dihydrate [J ] J C rystal Grow th, 1992, 125: [8 ] Zhang J, E rah impour A, N anco llas G H D ual constant compo sition studies of phase transfo rm ation of dicalcium pho sphate D ihydrate in to O ctacalcium Pho sphate[j ] J Co llo id and In terface Science, 1992, 152 (1): [9 ] Tom son M B, N anco llas G H M ineralization k inetics: A constant compo sition app roach [J ] Science, 1978, 200: [ 10 ] Koutsouko s P, Am jad Z, Tom son M B, et al C rystal grow th of calcium po sphateṡ A constant com 2 po sition study[j ] J Am erican Chem ical Society, 1980, 102 (5): [11 ] H eughebaert J C, Zaw alk i S J, N anco llas G H T he h row th of octacalcium pho sphate on beta tricalci2 um pho sphate[j ] J C ryṡ Grow th, 1983, 63: [12 ] L iu Y, N anco llas G H F luo rapatite grow th k inetics and the influence of so lution compo sition[j ] J C ryṡ Grow th, 1996, 165: [13 ], [M ] :,

7 58 ( ) 2001 Effect of sodium fluo ride so lu tion on the hydro lysis of CaH PO 4 2H 2O and the so lub ility of its hydro lysate CH EN Fe i, FEN G Zu2de, L IN Chang2jian (D ep ṫ of M aterials Sci and Engin, T he State Key L ab fo r Phyṡ Chem of So lid Su rfaces, X iam en U n iv, X iam en , Ch ina) Abstract: D ecrease of the so lub ility of the m ineral phases of teeth w ill aid in p reven ting carieṡ T he effect of fluo ride ion on the so lub ility of hydroxyapatite (Ca10 (PO 4) 6 (OH ) 2, HA P) has been w ell repo rted How ever, the effect of fluo ride ion on the so lub ility of the cal2 cium hydrogen pho sphate (CaH PO 4 2H 2O, DCPD ) w as no t very cleaṙ DCPD is one of the p recu rso rs of hydroxyapatite and the im po rtan t ino rgan ic com po sition s in teeth as w ell purpo se of th is study w as to investigate the hydro lysis characteristic of DCPD and HA P in N af so lu tion ṡ T he T he variation s of ph of DCPD hydro lysis in N af so lu tion s of concen tration ranging from to w ere determ ined by a ph electrode under 37 T he crystal structu re and m o rpho logy of the hydro lysate w as determ ined u sing XRD and SEM, respectively W hen the fluo ride ion concen tration in the so lu tion w as low er than , the ph at equ ilib rium decreased w ith the increase of fluo ride ion concen tration in the so lu tion How ever, due to the fo rm ation of CaF 2, ph increased to a h igh value w hen the flu2 o ride ion concen tration in the so lu tion w as T he XRD diffraction pattern s indi2 cated that w ith the increasing of fluo ride ion concen tration hydro lysate w as CaH PO 4, CaH 2 PO 4 + Ca10 (PO 4) 6F 2, Ca10 (PO 4) 6F 2, and Ca10 (PO 4) 6F 2+ CaF 2, respectively A t low fluo ride ion concen tration the fluo ride up take w as very clo se to the w ho le am oun t of the fluo ride in the in itial so lu tion A ph 2stat m ethod w as u sed to assess the disso lu tion p roperties of DCPD and its hydro lysate F rom the so lu tion cu rves it can be concluded that the calcium pho s2 phates becam e m o re resistan t to acid than they did befo re the fluo ridation Key words: ca lcium hyd rogen p ho sp ha te; sod ium fluo ride; hyd roxyap a t ite; ph 2sta t m ethod