牛奶氟化對人類牙釉質脫礦化之影響--體外研究

Abstract

第一章 氟素加入牛奶後之氟離子可得性 牛奶為嬰幼兒的主要食物或飲料，但常造成令父親及牙醫師困擾的「幼兒齲齒」(early childhood caries; ECC)。牛奶加氟用來抗齲的構想是在50年代被提出，目前英國、蘇俄、保加利亞、智利等國家使用此方式來做預防幼兒齲齒的方法之一；但多屬實驗性質。牛奶加氟最大的爭議在於認為氟離子會被牛奶中的鈣所結合，降低氟離子的可得性(availability)，因此牛奶加氟對齲齒預防之效益亦令人質疑。本研究的目的將測量氟化牛奶內氟離子的濃度，以得知氟素加入牛奶後，游離氟離子之存在情形。 本實驗各以去離子水與牛奶為基質，各加入等量的NaF 粉末，製成氟之水溶液及氟之牛奶溶液，以氟電極測量兩者之氟離子濃度，並比較之。結果在高濃度氟化牛奶（250-1000ppm）中，氟離子的可得量約為68％至83％；濃度越高，可得量越高。在低濃度氟化牛奶（0.19-19ppm）中，氟離子的可得量約為35％至65％；濃度越高，可得量越高。比較不同種類的沖泡式牛奶，以全脂牛奶的可得量最高，嬰兒牛奶其次，脫脂高鈣牛奶最低。因此儘管氟素會和牛奶中的物質結合，但還是有35％ 至83％游離之氟離子。 第二章 牛奶加氟對人類牙釉質脫礦化之影響 目前氟化物抗齲的機制，認為局部性的效果勝於系統性的效果，儘管氟化牛奶中氟離子可能會和牛奶中的物質結合，但仍有相當程度的游離氟離子，理論上應可在口腔內提供抗齲的功效。本研究的目的將以體外(in vitro)的方式比較牛奶、氟化牛奶對牙釉質脫礦化之影響，進一步瞭解牛奶、氟化牛奶與齲齒的關係。以連續脫礦法(continuous demineralization) 模式，分別將牙齒 (n=39) 置於脫礦化溶液 (Demineralization Solution); 酸化牛奶(Acidified milk) ; 酸化之氟化牛奶(Acidified F-milk )溶液中，以形成類齲病灶(caries-like lesion)，比較各組類齲病灶之大小。另一組實驗仿照White &Featherstone之體外模式(in vitro model)，分別將牙齒(n=28)置於脫礦化溶液/再礦化溶液(Demineralization Solution / Remineralization Solution); 酸化牛奶/再礦化溶液(Acidified milk / Remineralization Solution); 酸化之氟化牛奶/再礦化溶液(Acidified F-milk / Remineralization Solution)三種酸鹼循環(pH cycling)模式中，以形成類齲病灶，比較各組類齲病灶之大小。結果以連續脫礦法模式中，類齲病灶在三組中分別為各組之樣本(n=39)之100%、48.7% 及 33.3%。而類齲病灶之深度，以脫礦化溶液為最深，而含5ppm氟之酸化牛奶組所形成之病灶深度最小。另一組以酸鹼循環模式，類齲病灶在三組中分別為各組之樣本(n=28)之100%, 60.7% 及 32.1%。而類齲病灶之深度，以脫礦化溶液為最深，而含5ppm氟之酸化牛奶組所形成之病灶深度最小。由此可知酸性牛奶相對於對照組的再礦化溶液而言，形成之類齲病灶數量較少且其深度較淺，牛奶似乎具有抑制齲齒的功能。另外，在含氟之酸性牛奶中，形成之類齲病灶數量最少且其深度最小。牛奶加氟似乎可用於防齲。

Chapter 1 Availability of fluoride in fluoridated milk The nutrients supplied by milk are essential components of the human diet throughout life, especially for babies and young children. From mid-1950, several papers were published concerning the possible use of fluoridated milk as a dental caries preventive measure for children. However, some scientists questioned the suitability of using milk as a vehicle for fluoride, claiming that ionic fluoride interacts with milk constituents and, as a result would be irretrievably lost in the milk. The purpose of this study was to know the availability of fluoride ion after adding to milk. Exact same amount of NaF powder was dissolved into distilled water and milk. Fluoride electrode was used to measure and compare the ionic concentration of the samples . The results show : 1) In higher concentration of fluoridated milk (250-1000 ppm) , the availability of fluoride is about 68% to 83%. In lower concentration of fluoridated milk(0.19-19 ppm), the availability is about 35% to 65%. The higher the concentration, the higher the availability 3) To compare with different kinds of milk, the availability of fluoride is the highest in full milk, the lowest in the milk with lower-fat and higher calcium. In conclusion, although fluoride will bind with the components of milk when adding into milk , there are still available fluoride in fluoridated milk. The availability of fluoride in fluoridated skim with high calcium milk was lower than full milk and baby formula. Chpater 2 Effect of fluoridated milk on demineralization of human enamel The anti-caries effects of fluoride are primarily topical rather than systemic benefits. Although fluoride will bind with the components of milk when adding into milk , there are still available fluoride in fluoridated milk. Therefore, the amount of available fluoride is efficient for prevention of dental caries. The purpose of this study was to investigate the effect of milk and fluoridated milk on enamel caries formation in vitro. We compare the size of artificial caries-like lesions created in demineralization solution (DS), acidified milk, acidified 5 ppm fluoridated milk with the in vitro method of continuous demineralization (n=39) and pH-cycling (n=28). The results show that : 1) in the model of continuous demineralization (n=39), 100%, 48.7% and 33.3% of the specimen in respective group produced lesions. 2) in the model of pH-cycling (n=28), 100%, 60.7% and 32.1% of the specimen in respective group produced lesions. The depth of artificial lesions created most with DS, least with acidified fluoridated milk in both experiments. It seems that milk may have anti-caries effect, because the number of caries-like lesions and the depth of the artificial lesions created in milk were less than those in DS. The number of caries-like lesions and the depth of the artificial lesions created least with acidified fluoridated milk. It implied that the fluoridated milk can be used for the purpose of preventing dental caries.