23 1 V o l 23, N o 1 2003 1 TR IBOLO GY Jan, 2003 1, 3, 2, 1, 3 (1., 730000; 2., 200433; 3., 730050) : 3 ph,,, ;,. : ph = 4. 0, ; ph = 4. 0 ; ph = 2. 0 3.,,.,. : ; ; ; : TQ 174. 75 + 8 : A : 100420595 (2003) 0120042206,,,. 1980 1995 15, 26. 7%., [1, 2 ],. [3 ], 52% 5 6. P indbo rg [4 ], 3.,. 3, [5 ],. 1 1. 1,,,, 300 # 500 # 800 # 1 200 #, A l2o 3,.. 0. 06 ggl (m alic acid, M ) ( citric acid, C) ( lactic acid, L ), ph 2. 0 4. 0 2. 0. 4 g N ac l 0. 4 g KC l 0. 795 g CaC l2 2H 2O 0. 005 g N a2s 2H 2O 0. 78 g N ah 2PO 4 2H 2O 1 g, 1 000 ml,. 1. 2 56 7, 6 ( W ) 10 m in,. Op timo l SRV ;, 24 (, ) ; 2 ; 0. 5 mm, 10 H z, 20 N,, 6 000. 2201, : 2002203215; : 2002206220g, e2m ail: qiuyinong@w est163. com. :,, 1971,,.
1 : 43 ; (SEM ), X t. 7, 7 10 m in, Everone M H 25, 10,.,, 2. 1, JSM 25600LV (EDA X) Ca P. 2 1 7 1 Table 1 Averaged wear volume loss of enamel and standard dev iation af ter treated with distilled water and var ious ac id solution s and the one way ANOVA result So lution Samp les tested X { ṡ d. gmm 3 F value P value M 2. 0 8 0. 02648 0. 0044 M 4. 0 8 0. 02128 0. 0021 C2. 0 8 0. 0285 0. 0077 C4. 0 8 0. 02442 0. 0029 4. 32 P < 0. 01 L 2. 0 8 0. 02998 0. 0088 L 4. 0 8 0. 03355 0. 0102 W 8 0. 02054 0. 0034, M 2. 0 M 4. 0 C2. 0 C4. 0 L 2. 0 L 4. 0 W ph 2. 0 4. 0, F [6 ] : F = S A, S A = S A S E, S E= S E k- 1 n- k. (1) : S A ; S E ; k ; n, F = 4. 32, P 0. 00142,. t, F 2, t : : t= S x - y 1 n x + 1 ny ; (2) : t= - x - y S 2 x + S 2 y n x ny. (3) t 2, P < 0. 05, 2 t ( ) Table 2 Compar ison of the wear volume loss of enamel by t- test So lution L 4. 0 L 2. 0 C4. 0 C2. 0 M 4. 0 M 2. 0 W 3. 4 2. 81 2. 45 2. 66 0. 55 3 M 2. 0-1. 79 1 1. 11-0. 64 3. 01 - M 4. 0-3. 31 2. 7-2. 49-2. 54 - - C2. 0-1. 11 0. 36 1. 4 - - - C4. 0-2. 42 1. 69 - - - - L 2. 0-0. 75 - - - - - Refers to P < 0. 05, o therw ise P > 0. 05. P < 0. 05, P > 0. 05.,. : ph = 4. 0, ; ph = 4. 0, ; ph = 2. 0, 3 ; ph, ph 2. 0 4. 0. 2. 2 1
44 23 (a) D ecreasing rate of hardness (b) Increasing rate of toughness F ig 1 V ariation of hardness and toughness of enam el treated w ith different so lutions 1. :, M 4. 0 ; 3 ; ph 3 > >, > >. 2. 3 (, HA ) [7 ], : Ca10 (PO 4) 6 (OH ) 2 10Ca 2+ + 6PO 4 3- + 2OH - PO 4 3- + 3H + H PO 4 2- + 2H + H 2PO 4 3- + H + H 3PO 4,,,. ph 2. 2 4. 9 [8 ], ph 2. 0 4. 0. H ughes [2 ] 3, ph ; ; 30 m in 10 Λm, ;., HA, R etziu s, [9, 10 ],, HA Ca 2+ PO 4 3- OH -,,,,. 2 SEM. : [ 2 (a b) ],,,, ph = 4. 0, ph = 2. 0 ;,, [ 2 (c d) ];,,, ph = 2. 0 [ 2 (e f) ];, [ 2 (g) ]. Ca P [9 ], Ca P,. 3 EDA X. : ph = 4. 0, Ca P ph = 2. 0 ; ph = 4. 0 Ca, Ca P.., ph,, Ca P.,.,,,, [11 ].,
1 : 45 (a) T reated w ith M 2. 0 (b) T reated w ith M 4. 0 (c) T reated w ith C2. 0 (d) T reated w ith C4. 0 (e) T reated w ith L 2. 0 (f) T reated w ith L 4. 0 (g) T reated (h) M agnified im age of (a), w ith W W refers to w o rn area, N to eroded area F ig 2 SEM mo rpho logies of w o rn surfaces of enam el treated w ith different so lutions 2 SEM [ 2 (h) ],. 3,,,..,, ph = 2. 0 ph = 4. 0. ph, [ 4 (a) ], [ 4 (b) ].,,
46 23 F ig 3 V ariation of Ca and P content w ith in and out of the enam el w ear scar treated w ith different so lutions 3 C r P (a) T reated w ith C4. 0 (b) T reated w ith L 4. 0 F ig 4 SEM mo rpho logies show ing w ear debris of the enam el treated w ith C4. 0 and L 4. 0 4 C4. 0 L 4. 0 SEM, ph = 4. 0 ;,. ph = 2. 0,,,,,. [12 ],. Dogan [13 ],,,.,,,,,. 3 a. 3,. 3. b. ph (2. 0),, ; ph (4. 0),,. : [ 1 ] W est N X, M axw ell A, H ughes J A, et al. A m ethod to m easure clinical ero sion: the effect of o range juice consump tion on ero sion of enam el [J ]. 1998, 26: 3292335. Journal of D entistry, [ 2 ] H ughes J A,W est N X, Parker D M, et al. Effects of ph and concentration of citric, m alic and lactic acids on enam el, vitro [J ]. Journal of D entistry 2000, 28: 472152. [ 3 ] M O B rien. Ch ildren s dental health in the U nited Kingdom in
1 : 47 1993 [ R ]. O ffice of Population Censuses and Surveys, L ondon: HM SO, 1994. [ 4 ] P indbo rg J J. Patho logy of the dental hard tissues [M ]. Copenhagen: M unskgaard, 1970. [ 5 ] L i Hong ( ), Zhou Zhongrong ( ), Zhang J ie ( ), et a l. Comparative study of the friction and w ear behavio r of natural too th and several dental p ro sthetic m aterials ( ) [J ]. T ribo logy ( ), 2001, 21: 1722175. [ 6 ] Zhou H uaiw u ( ). M athem atical statistics ( ) [M ]. J inan ( ) : Shandong Educational P ress ( ), 1984. [ 7 ] Do rozhk in J R. Surface reactions of apatite disso lution [J ]. J Co llo id interf Sci, 1997, 191: 4892498. [ 8 ] M eurm an J H, H arkonen M, N averi H, et a l. Experim ental spo rts drinks w ith m inim al ero sive effect [ J ]. Scandinavian Journal of D ental Research, 1990, 98: 12028. [ 9 ] Yue Songling ( ). M odern caries ( ) [M ]. Beijing ( ) : Beijing M edical U niversity P ress ( ), 1993. [10 ] Johansson A K, So rvari R, B irkhed D, et al. D ental ero sion in deciduous teeth2an in vivo and in vitro study [J ]. Journal of D entistry, 2001, 29: 3332340. [11 ] D ing Suidong ( ). F racture D ynam ics ( ) [M ]. Beijing ( ) : Ch ina M achanical Industry P ress ( ), 1997. [12 ] Kong Yongfa ( ), Gong J ianghong ( ), Yang Zhengfang ( ). W ear of structural ceram ic ( ) [J ]. J of Ch inese Ceram ic Society ( ), 1998, 17: 32235. [13 ] Dogan C P, H aw k J A. M icro structure and abrasive w ear in silicon nitride ceram ics[j ]. W ear, 2001, 250: 2562263. Fr iction and W ear Behav ior of Human Enam el Eroded with D ifferen t Organ ic Ac ids Q IU Y i2nong 1, 3, L I Tong2sheng 2, L IU W ei2m in 1, L IU L an2zhong 3 (1. S tate K ey L aboratory of S olid L ubrication, L anz hou Institu te of Chem ical P hy sics, Ch inese A cad em y of S ciences, L anz hou 730000, Ch ina; 2. T he K ey L aboratory of M olecu lar E ng ineering of P olym ers, M inistry of E d ucation, S hang hai 201203, Ch ina; 3. D ep artm ent of S tom atology, L anz hou General H osp ital, L anz hou Comm and PL A, L anz hou 730050, Ch ina) Abstract: T he friction and w ear behavio r of 56 hum an enam el samp les eroded w ith differen t o rgan ic acids w ere investigated by sliding again st artificial po rcelain teeth on an Op timo l SRV o scillating friction and w ear test rig, u sing a syn thetic saliva as the lub rican t m edium. T he w ear vo lum e lo ss data w ere analyzed statistically. T he w ear scars of the enam el of the hum an too th ob served w ith a scann ing electron m icro scope and the elem en t concen tration s of Ca and P w ith in and ou t of the w ear scars w ere determ ined w ith energy dispersion spectrom etry. T he co rrelation among the w ear behavio r and the hardness and toughness of the enam el samp les w as discu ssed as w ell. A s the resu lts, the samp les gave h igher w ear vo lum e lo ss after eroded w ith the acids than imm ersed w ith distilled w ater, excep t that the one eroded w ith m alic acid of ph 4. 0 had a sm aller w ear vo lum e lo ss. T he lactic acid resu lted in the largest enam el w ear vo lum e lo ss, fo llow ed w ith the citric acid and m alic acid at a ph value of 4. 0 (p < 0. 05), bu t they show ed no sign ifican t difference at a ph value of 2. 0. T he enam els eroded w ith the o rgan ic acids w ere m ain ly characterized by ab rasive w ear and m icro crack ing. T he difference of w ear data w as attribu ted to the differen t co rro sive ab ility of the acids w h ich led to differen t action s to the m echan ical strength of the enam els and had little difference w ith decreasing ph va lue. T hough the w ea r2resistance of the enam els w a s rela ted to the ha rdness and fractu re toughness, it m igh t depend on variou s o ther facto rs as w ell. Key words: hum an enam el; o rgan ic acid; ero sion; w ear behavio r Author: Q IU Y i2nong, m ale, bo rn in 1971, L ectu rer, e2m ail: qiuyinong@vip. sina. com.