Turku sugar studies V: Final report on the effect of sucrose,fructose and xylitol diets on the caries incidence in man

The purpose was to study differences in the caries increment rate as influenced by various sugars. The trial involved almost complete substitution of sucrose (S) by fructose (F) or xylitol (X) during a period of 2 years. There were no significant initial differences as to caries status between the prospective sugar groups; 35 subjects in the S-group, 38 in the F-group, and 52 in the X-group. During the entire study 10 subjects discontinued or were excluded. The clinical and radiographical observer error was reported and discussed. After 2 years the mean increment of decayed, missed and tilled tooth surfaces was 7.2 in the S-group, 3.8 in the F-group, and 0.0 in the X-group. The weakness of the DMFS-index in not showing the development of new secondary caries and the increase in size of the lesions was overcome by expressing the caries activity in terms of indices showing the total quantitative and qualitative development. The results showed a massive reduction of the caries increment in relation to xylitol consumption. Fructose was found to be less cariogenic than sucrose. It was suggested that the non- and anticariogenic properties of xylitol principally depend on its lack of suitability for microbial metabolism and physico-chemical effects in plaque and saliva.     

Effects of xylitol and carbohydrate diets on dental caries, dentine formation and mineralization in young rats

Female Wistar rats were weaned at the age of 3 weeks and fed for 7 weeks either a high-sucrose diet, a non-cariogenic raw potato-starch diet, a high-sucrose diet with 5% xylitol supplement, a raw potato-starch diet with 5% xylitol supplement or a non-cariogenic, commercial, powdered rat food (Ewos R3) for reference. A low xylitol concentration reduced the progression and severity of carious lesions but did not affect dentine apposition or the width of predentine in rats fed high-carbohydrate diets. Widening of the predentine zone in rats fed a high-sucrose diet might reflect disturbed mineralization, which could not be explained by serum ionized calcium or phosphate ion levels and which could not be corrected by low xylotol concentrations. It is concluded that the reduced area of dentinal carious lesions after low xylitol supplementation is not dependent on dentine formation or mineralization, but rather on direct effects in the mouth.     

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.     

Plaque growth while chewing sorbitol and xylitol simultaneously with sucrose flavored gum

In a recent study, sorbitol flavored chewing gum was found neither to increase nor decrease the normal rate of plaque formation, whereas high plaque scores were obtained with sucrose gum during 4 days of no mechanical tooth cleaning. The aim of the present study was to see if chewing sorbitol or xylitol flavored gum together with sucrose gum would affect the growth rate of plaque and whether chewing of xylitol flavored gum could reduce the amount of already formed plaque. Twenty-seven dental students refrained from mechanical oral hygiene measures from Monday to Friday morning for 3 weeks. The students were randomly divided into three groups. A three time crossed-over double-blind approach was used. During each test period one group chewed a combination of one piece sorbitol and one piece sucrose flavored gum five times per day, the second group correspondingly chewed xylitol and sucrose flavored gum, while the third group served as a no hygiene control group. After each test period the students in the control group chewed one piece of xylitol gum every 15 minutes for 2.5 hours. The participants started out each week with clean teeth and were at the end of each test period scored for visible plaque on the facial, mesial and lingual surfaces of their teeth. There was somewhat more plaque after 4 days of chewing sucrose-sorbitol and sucrose-xylitol gum combinations than after no oral hygiene alone. There was no difference between the two test treatments. The 2.5-hour chewing of xylitol flavored gum after the no oral hygiene period did not result in a reduction of the 4-day-old plaque.     

Long-term effect of xylitol chewing gum on dental caries

About 85% (n = 269) of the subjects who participated in the Ylivieska follow-up studies on the effect of xylitol chewing gum on dental caries during 1982-84 or 1982-85 were re-examined in 1987 for the analysis of possible long-term preventive effects. Further caries reduction was found 2 or 3 yr after the discontinuation of the use of xylitol. The effect was especially marked in girls; the reduction in caries increment in the post-use years was 60% for the 2-yr users, suggesting that more pronounced caries reduction was associated with the most regular use of xylitol. In teeth erupting during the first year of the use of xylitol gum the long-term preventive effect was greater than in other teeth. Several explanations are suggested: lasting effect of the microbiological changes in the mouth, bacterial colonization on newly erupted teeth by organisms other than S. mutans, and/or thorough maturation of the teeth under favorable physico-chemical circumstances. The results suggest that the value of xylitol in caries prevention depends on the timing of the treatment in relation to the development of the dentition.     

Chlorhexidine and xylitol gum in caries prevention

This paper presents the current best evidence on the respective and comparative outcomes of chlorhexidine and xylitol and extrapolates these data to individuals with special needs. It analyzes the probable mechanisms of action for both chlorhexidine and xylitol then reviews individual products and discusses the anticipated effectiveness of these products in individuals with special needs.     

Effect of aluminum concentration on dental caries formation in the rat

OBJECTIVE: Topically applied aluminum (AI) reduced fissure caries in rats with indigenous microflora, but neither therapeutic activity nor concentration effects have been studied in animals infected with caries-inducing bacteria. This study investigated the effects of solutions containing various Al concentrations on formation of smooth surface and sulcal caries in cariogenically challenged rats infected with Streptococcus sobrinus.
METHODS: Weanling rats, inoculated with S . sobrinus, were randomly assigned to six groups which were topically treated twice daily with water (treatment control), a NaF solution of 100 parts/10⁶ F (positive control), or AIK(SO₄)₂ solutions containing 100, 1000, 2000, or 4000 parts/10⁶ Al. Rats were fed a high-sucrose diet and distilied water ad libitum for 10 weeks, then the molars were scored for enamel and dentin caries.
RESULTS: Relative to the water control, NaF and all Al solutions significantly reduced prevalence of both smooth-surface and fissure caries. Protection by Al solutions was greater on smooth surfaces than sulcal areas. Al treatments reduced smooth surface scores by 49–7I% and sulcal scores by 27–53%. For all comparisons the protective effect of the 100 parts/10⁶ Al solution was less than solutions containing 1000 parts/10⁶ Al or more. NaF and all Al solutions also significantly reduced the extent of lesion penetration into dentin.
CONCLUSIONS: Topically applied AI reduced the formation and progression of both smooth surface and Sul. cal caries and showed evidence of a dose response in a rat model infected with S. sobrinus.     

Role of sucrose in plaque formation

Results are presented which support the concept that the bacterial enzyme glucosyltransferase (GTF) plays a crucial role in sucrose induced plaque formation. GTF was shown to adhere strongly to anionic, hydrophobic and polysaccharide solid materials, and to be able to produce glucans in the adsorbed state. It appears conceivable that GTF adsorb to teeth and produce glucans. Glucan chains on (he surface of the bacteria and glucans on the tooth surfaces interact (pack) and form a strong binding mechanism. The rigid α1,3 linked glucans produced by Streptococcus mutans are particularly suited for interaction of this kind. This mechanism could account for sucrose-induced binding of bacteria to enamel, pellicle covered enamel and preformed plaque. S. mutans would adhere particularly strongly to tooth surfaces in the presence of sucrose, according to this model.     

Dental caries and sucrose intake in five South African preschool groups

Abstract Dental caries, debris (DI-S) and sugar intake were determined for 766 rural Black, urban Black, coloured, Indian and While children, using standardized techniques. In general sucrose intake, both quantity and frequency was low in rural Black children yet these children had relatively few caries-free individuals and higher than expected mean dmft scores. Comparison with earlier studies in the same localities has shown a worsening of dental caries in all groups except the White, in which the situation has improved. Sucrose consumption declined in rural Black, and White groups, remained steady in urban Black children and increased in coloured and Indian groups.     

Effect of dextranase on plaque formation and caries development in the rat

abstract — Plaque formation and caries development were studied in 0-M rats fed Diet 2000 and infected with S. mutans 6715 and fecal flora from older caries-active rats. Merck dextranase, Beckman dextranase or Beckman glucanase 447 were administered singly or in combination to groups of 12 rats either as an addition to the diet or as a "mouthwash" twice daily, 5 d per week. All enzymes studied were associated with significant inhibition of both plaque formation and caries development, especially on the buccal and lingual surfaces.     

部分去龋法治疗恒磨牙深龋的疗效观察

目的:探讨部分去龋治疗恒磨牙深龋的临床疗效.方法:对102颗恒牙深龋进行部分去龋法结合树脂严密充填,随访6个月以上,评价其牙髓存留率及治疗主观感受.结果:随访到的97颗患牙中,90颗充填物完好,牙髓活力正常,治疗成功率为92.8％;79.9％的患者治疗感受为轻度不适或无反应.结论:部分去龋法治疗恒牙深龋,可以减少牙髓暴露的风险,减轻患者治疗时的不适,获得较好的充填治疗效果,值得临床推广.     

Effect of fluoridated sucrose on rat caries

The present study was designed to test the effect of frequent pulses of low fluoride levels on rat caries when supplied in a standardized cariogenic rat diet containing 67% sucrose (MIT-200). The test diets were variants of Diet MIT-200 in which the sucrose component had been fluoridated with NaF solution resulting in total concentrations of 0 (control), 2, 3, 5, 10, or 20 ppm fluoride in the final diets. Rats received one of the test lots 17 times daily in a programmed feeding machine beginning at age 22 days, and were inoculated with Streptococcus mutans at age 23, 24, and 25 days. After 5 weeks, the rats were sacrificed and their mandibular molars scored for number and severity of sulcal, buccolingual, and proximal caries. Frequent daily pulses of as little as 2 ppm fluoride in dietary sucrose were effective in significantly (p less than 0.01) reducing buccolingual rat caries.     

第一恒磨牙患龋与乳磨牙患龋相关性的研究

目的 探讨6～10岁儿童第一恒磨牙患龋与乳磨牙患龋的相关性,以期为临床提供参考.方法 采用整群、分层、随机抽样的方法,抽取济南市10个区(县)40所小学,对6 ～ 10岁符合纳入标准的3680名儿童进行患龋情况调查,并分析第一恒磨牙患龋率与年龄、性别及乳磨牙患龋之间的相关性,对第一恒磨牙龋失补牙数(decayed-missed-filled teeth,DMFT)、龋失补牙面数(decayed-missed-filled surfaces,DMFS)及乳磨牙龋失补牙数(decayed-missed-filled teeth,dmft)、龋失补牙面数(decayed-missed-filled surfaces,dmfs)进行相关分析.结果 6～10岁第一恒磨牙DMFT为1440,龋均0.39(1440/3680);患龋率20.7％ (763/3680),女性患龋率[28.9％ (509/1762)]显著高于男性[13.2％ (254/1918)] (P ＜0.01);第一恒磨牙患龋率随年龄增长呈上升趋势.第一恒磨牙DMFT与乳牙dmft呈显著正相关关系(r=0.31,P＜0.01),DMFS与dmfs呈显著正相关(r=0.35,P＜0.01).当dmft＞3、dmfs＞ 19时第一恒磨牙患龋率成倍增长.结论 第一恒磨牙患龋率与性别、年龄及乳磨牙患龋指数有关,对乳磨牙高龋患者应早期对第一恒磨牙采取必要的防龋措施.     

Effect of the antineoplastic agents doxorubicin and methotrexate on rat caries and secondary dentin formation

Because childhood cancer and/or its therapy is known to increase both dental caries and developmental defects in enamel, this experimental study was carried out to obtain information on the effect of two frequently used anticancer drugs, doxorubicin and methotrexate, on fissure caries and dentinal metabolism in healthy rats. Both drugs significantly reduced caries prevalence in the rat molars, the dentinal lesions that developed also being smaller than in the controls. Secondary dentin formation was slightly reduced, probably because of the lower caries prevalence in the rat molars and/or because of the action of the drugs. Thus, these two drugs could scarcely have been the reason for the increased caries activity in cancer patients.     

Turku sugar studies VII:Principal biochemical findings on whole saliva and plaque

Plaque and whole saliva samples of the subjects of the Turku sugar studies were analyzed for several enzymes and biochemical compounds. Strict xylitol diet maintained throughout the study a 50^o₀ lower quantity of plaque than the sucrose or fructose diets. Decreased plaque and whole saliva lactate concentration, diminished activity of salivary amylase, and reduced hydrolysis rate of sucrose in plaque and whole saliva were observed in relation to xylitol consumption. The xylitol diet also reduced the ratio of glucose to proteins in plaque. On the other hand, increased activity in plaque of α and β-glycosidases (against p₂- and 2-nitrophenyl derivatives), fucosidase and aspartate transaminase, as well as increased activity of proteinases and lactoperoxidase in saliva were found in connection with xylitol consumption. The fructose diet caused less clear differences when compared to sucrose, but the experiments indicated a selectivity of the effects of dietary carbohydrates on the biochemistry of whole saliva, plaque and salivary glands. The results contribute in explaining the cariostatic effects of xylitol and the lower cariogenici-ty of fructose when compared to sucrose.     

Molecular pathogenesis of root dentin caries

Human dentin has a higher content of organic matrix and more non-ideal hydroxyapatite than human enamel. Ultrastructural studies indicate that root caries involves both mineral dissolution and breakdown of the organic matrix. Factors involved in the root caries process seem more complicated than those in enamel caries. Moreover, the distinct roles of acids and enzymes and the sequence of events in the root caries process are not well-understood. Although Streptococcus mutans and Actinomyces viscosus are considered to be major pathogenic micro-organisms of root caries, their roles in degradation of the organic matrix components of root dentin need clarification. The purpose of this paper is to review the basic composition of root dentin and the roles of acids and both endogenous and bacterial enzymes in the root caries process.     

冠部牙本质深龋细菌学分析

目的：探明牙本质深龋中的主要相关菌。方法：利用色谱法、裂解法等对龋坏牙本质分三层作细菌分离、鉴定、分析。结果：牙本质龋中的主要相关菌为乳杆菌和变链菌,龋内层牙本质中的细菌含量较外层少。结论：乳杆菌促进牙本质龋的发展,在牙本质龋进展中脱矿在先,细菌入侵在后。