Xylitol in caries prevention: what is the evidence for clinical efficacy?

Xylitol has attracted much attention as an alternative sweetener. Essentially all clinical studies concerning the effect of xylitol on caries development consent to its non-cariogenicity and to the beneficial effect of substituting sucrose with xylitol in chewing gums and sweets. However, claims of anti-caries or therapeutic effects, and superiority of xylitol over other polyols are still to be confirmed by well designed and conducted studies from independent research groups.     

木糖醇注射液与临床常用五种抗菌药物的配伍稳定性考察

目的模拟临床常用静滴浓度,研究阿奇霉素、氨苄青霉素钠、羟氨苄青霉素钠、头孢曲松钠、加替沙星五种常用抗菌药物与木糖醇注射液的配伍稳定性。方法采用紫外分光光度法测定8 h内配伍液中五种药物的含量变化,同时观察室温(25℃)下的外观及pH变化。结果阿奇霉素、加替沙星、头孢曲松钠和木糖醇注射液配伍后在室温下8 h内外观、含量、pH值没有明显变化,保持稳定状态。但氨苄青霉素钠、羟氨苄青霉素钠和木糖醇注射液配伍后在室温下2 h后含量明显下降。结论在上述条件下,木糖醇注射液可与阿奇霉素、加替沙星和头孢曲松钠配伍应用。但与氨苄青霉素钠、羟氨苄青霉素钠配伍不稳定。     

木糖醇牙膏对菌斑抑制效果的临床试验

目的:评价木糖醇牙膏在抑制菌斑生成的临床效果。方法: 60名军校学员随机分为3组,即黑妹木糖醇牙膏组、黑妹空白牙膏组、高露洁全效牙膏组,双盲法评价1周和4周后的刷牙效果。结果:使用木糖醇牙膏4周后,试验组全口平均菌斑指数持续下降,第4周与第1周比较P<0. 01。1周后,三组菌斑清除率无显著性差异; 4周后,黑妹木糖醇牙膏组平均菌斑清除率最高。黑妹木糖醇牙膏组与高露洁全效牙膏组菌斑清除率无显著性差别,而与黑妹空白牙膏组比较有显著性差异。结论:长期使用木糖醇牙膏能显著抑制牙菌斑形成,黑妹木糖醇牙膏与高露洁全效牙膏抑菌效果相当,均优于不含木糖醇的空白牙膏。     

Effect of xylitol on mutans streptococci and lactic acid formation in saliva and plaque from adolescents and young adults with fixed orthodontic appliances

This study aimed to investigate two dose regimens of xylitol-containing tablets on the ecology of dental plaque and saliva during treatment with fixed orthodontic appliances. The study group comprised 56 healthy patients (mean age 15.8 yr) randomly assigned into the following groups: A, (n = 23) two xylitol tablets two times a day (1.7 g xylitol d(-1)) for 18 wk; B, (n = 23) two tablets four times per day (3.4 g xylitol d(-1)) for 18 wk; and C, (n = 10) no tablets. The levels of mutans streptococci (ms) were enumerated in plaque and saliva and the proportion of xylitol-sensitive (X(S)) strains in saliva was determined by autoradiography with [(14)C]-xylitol at baseline and at 6, 12, and 18 wk. The lactic acid formation rate was assessed enzymatically in sucrose-challenged plaque suspensions. A drop in salivary ms levels was found in Group A after 6 wk but not after 12 or 18 wk. The proportion of X(S) ms was decreased after 6 wk in groups A and B and remained so during the experimental period. The lactic acid formation rates decreased slightly ( approximately 10%) in the two xylitol groups compared with baseline. In conclusion, our results showed that although an alteration of ms strains was demonstrated following a regular daily low-dose intake of xylitol, the long-term total ms counts in plaque and saliva as well as plaque acidogenicity remained unchanged.     

人体新能源木糖醇及其应用

木糖醇不需胰岛素的促进能通过细胞膜成为组织的营养并转化为能量,口服或静滴木糖醇均不影响血糖。木糖醇还有抗酮体作用和刺激胰脏分泌胰岛素的功能,是糖尿病人代谢异常的调整剂和营养剂,并能促进肝糖原的合成,降低转氨酶,还能提高葡萄糖和氨基酸的利用率,适用于治疗年老体弱重症糖尿病和危重病人及其他手术前后病人的能量补充。     

Effect of xylitol on dentin formation in molars of adult rats

A xylitol-induced reduction in dentin formation has been observed in molars of post-weanling rats, but the effect in older animals with a slower rate of secondary dentinogenesis has not been investigated. We examined the effects of different concentrations of dietary xylitol on dentinogenesis in molars of young adult rats. The control group received a commercial basal diet, while for the other 3 groups, the same diet was supplemented with 5. 10 and 20% of xylitol. After 8 weeks, dentin thickness beneath the main fissures in the mandibular 1st and 2nd molars was measured. The final body weights did not differ between the groups. Dentin formation in the 1st molars of the 10 and 20% xylitol groups was significantly lower as compared to the controls, whereas no difference was found between these 2 groups. In conclusion, dietary xylitol reduces dentin formation in young adult rats in spite of the slow rate of dentinogenesis.     

Effects of xylitol, xylitolsorbitol, and placebo chewing gums on the plaque of habitual xylitol consumers

Xylitol reduces plaque but the reduction mechanism is largely unknown. The main aim of the present study was to determine whether the xylitol-induced reduction in the amount of plaque and the number of mutans streptococci could be demonstrated in subjects with (presumably) high levels of xylitol-resistant (X^R; not inhibited by xylitol) mutans streptococci acquired following previous xylitol consumptions. 37 healthy dental students participated in the double-blind study. All subjects had been uncontrolled, habitual consumers of xylitol-containing products for at least 1 yr before the study, A 1-month washout period was followed by a 2-week test period during which either xylitol, xylitol-sorbitol or unsweetened chewing gum base was chewed 3–5 × a day. Plaque and saliva samples were collected at baseline and at the 2-week point for determination of the amount of plaque, microbiological variables, and hydrolytic enzymes. Mixtures of xylitol and sorbitol seemed to perform equally well with respect to reduction in the amount of plaque but not the number of mutans streptococci. Thus, polyols were the active ingredients of chewing gums able to modulate the amount of plaque and its microbial composition. Xylitol reduced plaque with a mechanism which appeared not to be associated with the study-induced changes in the proportion (%) of mutans streptococci in plaque, the number of salivary mutans streptococci, the proportion of X^R strains in plaque or saliva, or the hydrolytic enzyme activities of plaque.     

Are sodium lauryl sulfate–containing toothpastes suitable vehicles for xylitol?

The hypothesis to be tested in this study was that toothpastes containing sodium lauryl sulfate (SLS) is unsuitable vehicles for xylitol. The bacteriostatic (and cariostatic) effect of xylitol is assumed to be caused by intracellular accumulation of xylitol-5-P in plaque bacteria. Experiments were designed to investigate whether presence of SLS would affect the uptake of xylitol by interacting with the bacterial membranes and thus inhibit xylitol-5-P formation. It was shown in an in vitro study that even very low concentrations of the strong anionic detergent SLS inhibited uptake of xylitol and xylitol-5-phosphate formation by dental plaque totally. The mild nonionic detergent ethoxylated stearyl alcohol (30x EO) had no such effect. In vivo experiments with toothpastes containing xylitol and either the strong or the mild detergent, showed that xylitol in toothpaste with SLS was not available for the plaque bacteria and gave no adaptation to xylitol, whereas in the presence of 30x EO it was available, and a xylitol adaptation was observed. Glucose metabolism, which was also studied for the plaque samples, was not significantly affected by presence of any of the 2 detergents, indicating that the amounts of xylitol in toothpastes were presumably too low to give clinical significant effects, even when mild detergents are used.     

E-Beam Effects on Poly(Xylitol Dicarboxylate-co-diol Dicarboxylate) Elastomers Tailored by Adjusting Monomer Chain Length

Poly(xylitol dicarboxylate-co-diol dicarboxylate) elastomers can by synthesized using wide variety of monomers with different chain lengths. Obtained materials are all biodegradable, thermally stable elastomers, but their specific properties like glass transition temperature, degradation susceptibility, and mechanical moduli can be tailored for a specific application. Therefore, we synthesized eight elastomers using a combination of two dicarboxylic acids, namely suberic and sebacic acid, and four different diols, namely ethanediol, 1,3-propanediol, 1,4-buanediol, and 1,5-pentanediol. Materials were further modified by e-beam treatment with a dose of 100 kGy. Materials both before and after radiation modification were tested using tensile tests, gel fraction determination, ¹H NMR, and ¹³C NMR. Thermal properties were tested by Differential Scanning Calorimetry (DSC), Dynamic Thermomechanical Analysis (DMTA) and Thermogravimetric Analysis (TGA). Degradation susceptibility to both enzymatic and hydrolytic degradation was also determined.