第17章P401-3

Switzerland




Considerable agreement exists that sucrose-containing snack foods are the most cariogenic entity in the Western diet. If industry is to make substitutions for sucrose in these products, it would not only want government permission to do so, but also perhaps recognition of such. Clinical investigations to determine the relative cariogenicity of food items containing these substitutes are expensive, difficult to perform and time consuming to the extent that they probably will never be performed, (The Turku-xylitol study is the exception). Alternate methods of assessing the relative cariogenicity of these foods have been proposed, such as animal feeding studies, in vivo plaque studies, in vitro metabolic studies of pure cultures of cariogenic bacteria, and in vivo plaque pH measurements. The last approach, that of measuring the plaque pH response by continuous pH measurements after exposure to the test food, (See "Continuous in vivo pH measurements" in Chapter 10), has been used in Switzerland to define various sucrose substitutes, and confections containing them, as "safe for teeth."



The Swiss Office of Health in the late sixties defined sugarless confections as those containing no fermentable hexoses or disaccharides. These products are sweetened with sucrose substitutes which are nonacidogenic, such as xylitol, or hypoacidogenic, such as sorbitol, mannitol, maltitol and Lycasin™ In order to obtain the description "safe for teeth" the confections are tested by pH telemetry.



In these studies the various sucrose substitutes are administered to volunteers either as a ten percent aqueous rinsing solution or as existing ingredients in marketed products, such as chewing gums, toffees and hard candies. At the beginning and end of each session, as well as between treatments, the neutralization of acidified plaque is achieved by stimulating salivary flow with chewing of neutral paraffin. In the example shown in Figure 17-4, the pH response of seven-day-old plaque (heavy line) and on a plaque-free, lingual surface (light line) is measured following rinsing with either a sucrose or xylitol solution. A three-minute rinse with sucrose rapidly dropped the plaque pH to about 4.0, where it remained until a water rinse, followed by a three percent carbamide rinse (U) and paraffin chewing (PC) restored the pH to about 7.0. A three-minute rinse with xylitol did not lower the pH below 6.0.



瑞士

大多同意在西方飲食中，最容易造成蛀牙的因素是含有蔗糖的零食。若食品企業想使用其他替代物來取代蔗糖，這不只是需要政府的批准，或許需要承認這是必需的機制。臨床上研究包含蔗糖代替物的食品內所含造成蛀牙的相關成分比例是需要大量經費，有執行上的困難，且相當耗時，導致研究無法執行。(The Turku-xylitol study是例外) 其他評估在食物中會引起蛀牙的成分比率的方法也被提出，例如動物餵食實驗(animal feeding study)，人體內牙菌斑實驗(in vivo plaque study)，純粹造成蛀牙的細菌培養在體外代謝實驗?(in vitro metabolic studies of pure cultures of cariogenic bacteria)，以及人體牙菌斑pH值的測量(in vivo plaque pH measurements)最後的方法是，測量牙菌斑在接觸受測食物後，連續對pH值變化的反應(見第十章continuous in vivo pH measurements)。這個測試方法，已在瑞士被使用來確認哪些蔗糖的代替品及其他含此代替品的甜點，用以確定哪些對牙齒是無害的(safe for teeth)。



在1960年晚期瑞士的衛生局定義無糖甜點為不可發酵的已醣或雙醣。這些產品使用蔗糖替代品使其有甜味，這些替代品是不產酸的，像是xylitol，或較不產酸的，像是sorbitol, mannitol, maltitol, Lycasin。測量pH值來區分哪些是對牙齒無害的(safe for teeth)零食。



在這些研究中，不同的蔗糖替代物被提供給自願者以10%濃度的液狀漱口水，或是口香糖、太妃糖及糖果。在個別期間的開始及結束的時間點，及實驗期間中間，藉由咀嚼中性的蠟片刺激口水分泌，來取得酸化的牙菌斑並將其中和，在fig17-3的例子中，測量以蔗糖或xylitol漱口水漱口後七天牙菌斑的pH值反應(粗線)，及在舌側無牙菌斑的表面pH值反應(細線)，在用蔗糖水漱口三分鐘後，其牙菌斑的pH值顯著的下降至4.0，此pH值持續維持4.0直到用水漱口並用3% carbamide rinse (U)及咀嚼蠟片(PC)後，pH值才回復到7.0。以xylitol漱口水漱口三分鐘後，並不會降低pH至6.0以下。



Fig. 17-4

Telemetrically recorded pH in seven-day-old plaque during and after treatment with 10 percent aqueous solutions of sucrose and xylitol, respectively. See text for additional explanations.

Imfeld, T. and Muhlemann, H.R., 1977. J. Prevent. Dent. 4:8-14.



Fig 17-3

測量記錄以10%濃度的液狀蔗糖漱口水及xylitol漱口水漱口前後，七天後的牙菌斑之PH值，請看內文以得到更多解說。

Imfeld, T. and Muhlmann, H.R., 1977. J. Prevent. Dent. 4:8-14







After considerable experience with this methodology, the Zurich group has recommended that a test substance which did not cause the plaque pH to drop below 5.7 for up to 30 minutes after its exposure to the plaque, should be considered as not harmful for teeth. The Swiss government accepted this recommendation and allows Swiss manufacturers, whose products do not lower the pH in this assay system to below 5.7, to advertise that their confections are "safe for teeth". The pH 5.7 value was chosen because it allowed a margin of safety above the critical pH range of 5.0 to 5.5. Candies, toffees, lozenges and chewing gums containing sorbitol, mannitol, xylitol or Lycasin™ have passed this test and are widely marketed in Europe. Food products sweetened with high-fructose corn syrup probably would not be found "safe for teeth" in this pH assay because the fructose should be readily fermented by the plaque bacteria (See Fig. 17-1).



This Swiss government approach to preventive cariology is to be admired as it is based upon scientific results and provides protection and benefits to its citizens. An atmosphere was created which facilitated industry's cooperation with the achievement of better dental health.



在以此實驗方法實驗後，Zurich等人建議，暴露在此實驗物質三十分鐘後不會造成牙菌斑內pH值降到5.7以下的物質，可被視為對牙齒無害的。瑞士政府接受此建議且准許瑞士製造商，生產不會造成pH值5.7以下，才可在產品上標示廣告，說明此產品對牙齒是無害的。選擇pH值5.7是因為，5.7剛好超過安全的pH值(5.0-5.5)。糖果、太妃糖、錠劑和口香糖中含有sorbitol, mannotl, xylitol, Lycasin已經通過此測試且已廣泛在歐洲被生產。以加入高濃度果糖糖漿產生甜味的食品可能不會在此論文中被發現對牙齒是無害的，因為果糖會很快的被牙菌斑中的細菌發酵。



瑞士政府對預防蛀牙的做法是被稱讚的，因為這是根據科學實驗結果且提供國民保護及助益。為了達到更好的牙齒健康，政府必須創造促進產業合作的環境。



SUMMARY



The usage of sucrose substitutes in snack-type foods is a logical and practical means of reducing caries incidence without perturbing normal dietary eating patterns. Carbohydrate substitutes, such as glucose, fructose, or high-fructose corn syrups are readily fermented by the plaque flora and therefore, may not be as noncariogenic as the polyol substitutes such as sorbitol, mannitol and xylitol. S. mutans and L. casei can ferment mannitol and sorbitol but are inactive towards xylitol. Xylitol is comparable to sucrose in sweetness and has been shown to be noncariogenic, and possibly anticariogenic when substituted for sucrose in foods and in chewing gums. In the United States, FDA regulations restrict the usage of food additives. In Switzerland, plaque pH studies are used to determine whether a sucrose substitute is fermented to below pH 5.7. Any compound or products containing these compounds, which are not so fermented, can be labeled as safe for teeth.



Summary

使用蔗糖替代物的零食，可以減少蛀牙產生且不需改變平常的飲食習慣。碳水化合物的替代品，像是葡萄糖、果糖、或高濃度果糖糖將會很快的被牙菌斑中的細菌發酵，因此，並不會像sorbitol, mannitol, xylitol等不易造成蛀牙的物質。S. mutans和L. casei可以使sorbitol, mannoitol發酵但不會對xylitol作用。Xylitol的甜味跟蔗糖差不多且被證實為不會造成蛀牙，甚至用來代替食物及口香糖中的蔗糖，且有抑制蛀牙的作用，在美國，FDA規範禁止使用食品添加物。在瑞士，是用牙菌斑pH值的研究來決定是否蔗糖替代物會在pH值5.7以下被發酵。任何含有此物質的複合物或產品，不被發酵，才可以被標是為對牙齒是無害的(safe for teeth)。