Jaakko Tiekso

Xylitol chewing gum in caries prevention: a field study in children

As the prevalence of dental caries decreases in industrialized nations like the United States, it simultaneously increases in developing nations and Third World countries. The decrease in the West is attributed to increased use of fluorides, but the increase in developing countries has been explained by an increase in the consumption of sugar. As this information continues to propel researchers to find sucrose substitutes, xylitol has been singled out as a proposed sucrose replacement. The question tackled by this study was: Can the daily use of chewing gum containing xylitol increase the efficacy of the existing caries-preventive measures now regularly used for 11- to 15-year-old children in most industrialized western countries?

Long-Term Effect of Xylitol Chewing Gum in the Prevention of Dental Caries: A Follow-Up 5 Years after Termination of a Prevention Program

About 65% of the original 258 children who participated in 1982-1984 in a caries prevention program involving the use of xylitol chewing gum were retrieved in 1989 for a follow-up study. Ninety-five subjects from the original xylitol (X) group and 70 subjects from the original control (no-gum, C) group were available. In 1984, when the children completed the program at the age of 13-14 years, the caries scores were significantly lower in children who had used xylitol gums daily, compared with the C group. In 1989, 5 years after the discontinuation of the gum program, the difference between the X and C groups had continued to increase in favor of the X group. These effects were explained by assuming that the X gum program had facilitated the establishment of a low-virulent bacterial flora on the surfaces of the teeth, and especially on those teeth that erupted during the trial proper. This type of results are possibly helpful when evaluating cost-benefit ratios of caries prevention.

Oral Biochemical Status and Depression of Streptococcus mutans in Children during 24- to 36-Month Use of Xylitol Chewing Gum

Plaque and whole saliva samples were collected from initially 11- to 12-year-old children randomly chosen from two groups which participated in a 2- to 3-year field trial designed to test the efficacy of xylitol chewing gums in caries prevention. No initial differences were observed between the groups with regard to the plaque levels of Streptococcus mutans, but at the end of the 2-year xylitol gum regimen, the levels were smaller (p less than 0.05) in children using xylitol gum than in control children. In a similar follow-up study on children who were considered to be at high risk with regard to dental caries and who continued the study over a 3rd year, the xylitol-consuming subjects showed at the end of the study significantly smaller (p less than 0.004) salivary S. mutans counts than the control children. These effects were achieved after using up to 3 xylitol gums/day (daily xylitol dose per child was 7-10 g). Salivary flow rate and several salivary chemical parameters did not change.

Collaborative WHO xylitol field studies in Hungary I. Three-year caries activity in institutionalized children

The aim of this 3-year field study was to assess the value of partial substitution of sucrose with peroral xylitol (14-20 g/day) as a caries-preventive measure (X group) in comparison with systemic administration of fluoride (F group) and restorative treatment procedures solely (C group). An F dentifrice was used unsupervised in the X and F groups, the former containing 10% xylitol. The C group used customary, predominantly F-free dentifrices distributed by the local health authorities. The final material consisted of 689 institutionalized children (6-11 years). Caries was scored yearly in duplicate by two continuously calibrated teams. At base line the X group had a significantly higher caries prevalence than the F and C groups. The 3-year DMFS increment was 4.2 in the X group, 6.5 in the F group, and 7.7 in the C group. The corresponding ratio (RS) between caries incidence and the tooth surface population at risk was RSx, 4.9; RSF, 6.6; and RSC, 8.6. It is concluded that dietary xylitol in solid sweets resulted in a lower increment of caries than obtained in the F and C groups (p less than 0.001, covariance analysis, with base-line prevalence, number of permanent teeth, and visible plaque index as covariants).

Flow Rate and Composition of Whole Saliva in Rural and Urban Tanzania with Special Reference to Diet, Age, and Gender

The association of flow rate and biochemical and microbiological characteristics of saliva with diet was studied in 83 12-year-old children and in 127 adults (84 in the age group 35-44 years, 43 in the age group 65-74 years) living in rural and urban communities in Tanzania. No significant differences were observed between the salivary flow rates of the rural and urban subjects. The mean salivary flow rates were slightly lower in women than in men and significantly lower in the 12-year-old children than in the two older age groups (p < 0.05). The buffer effect was higher in the rural than the urban population. Further, it was lower in women than in men (p < 0.001). Salivary protein, IgG, and sialic acid concentrations were significantly higher in the rural than in the urban population, whereas amylase activity and IgA concentrations were lower. Microbiological studies showed mutans streptococci in 97% of the rural and in 91% of the urban subjects (n.s.). Lactobacilli grew significantly less often in the rural than urban samples (p < 0.01). Analyses of 24-hour dietary recalls showed that the rural and urban diets differed. The proteins in the rural diet were largely of plant origin, while in the urban diet animal proteins dominated. The rural diet contained also less sucrose but more fibre (mainly from grain) than the urban diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Collaborative WHO xylitol field studies in Hungary VII. Two-year caries incidence in 976 institutionalized children

The aim was to assess caries increment as influenced by partial substitution of sucrose by xylitol (X group) over a 2-year period in comparison with systemic fluoride (F group) and restorative treatment only (C group). The study differed from the 3-year field study of the same series primarily in that existing base-line differences were eliminated because the protocol required that all the new subjects entering the institutions in the 1st year were to be included for a 2-year trial. During this period the number of dropouts was 243 (19.9% of all subjects), the final material consisting of 976 children (6-12 years old). The 2-year DMFS increment was 3.8 in the X group, 4.8 in the F group, and 6.0 in the C group. The corresponding ratio (RS) between caries incidence and the tooth surface population at risk was RSX, 4.5; RSF, 5.5; and RSC, 7.5. The xylitol regimen resulted in a lower increment of caries than measured in the F and C groups (p less than 0.001; convariance analysis, with base-line prevalence, number of permanent teeth, and visible plaque index as covariants.

PHYSICAL, CHEMICAL, AND HISTOLOGIC CHANGES IN DENTIN CARIES LESIONS OF PRIMARY TEETH INDUCED BY REGULAR USE OF POLYOL CHEWING GUMS

A previous clinical trial showed that long-term use of saliva-stimulating polyol (xylitol and sorbitol) chewing gums was associated with arrest of dental caries in young subjects. After a 20-22-month intervention (when the subjects were 8 years old), a total of 23 primary teeth with extensive dentin caries lesions whose surface in clinical examination was found to be totally rehardened (remineralized) could be removed because the teeth were near their physiologic exfoliation time. These teeth were subjected to histologic, microhardness, and electron microscopic tests. The majority of the specimens had been remineralized from the surface by a non-cellular-mediated process within the remaining collapsed, organic extracellular matrix associated with the remaining dentinal surface. Many of the underlying dentinal tubules were filled with a matrix that had been subsequently mineralized. Dental microanalyses showed that the topmost (outer) 20-microm-thick rehardened layer of the lesions exhibited the highest Ca:P ratio, which leveled off at a depth of approximately 150 microm. The rehardened surface layer (normally <0.1 mm in thickness) was significantly (P < 0.001) harder than sound dentin and nearly as hard as sound enamel. Although the main source of the mineral present in the rehardened layer was most likely of salivary origin, some extracellular remineralization was probably mediated by odontoblasts. The results complete the dinical diagnoses of the original trial and suggest that regular use of polyol chewing gums may induce changes in dentin caries lesions, which in histologic and physiochemical studies show typical characteristics of rehardening and mineralization.