Effects of frequent mouthrinses with palatinose and xylitol on dental plaque.

The aim was to evaluate the effects of frequent mouthrinses with palatinose, xylitol and a mixture of palatinose and xylitol on plaque pH, plaque formation and cariogenic microorganisms. 15 subjects refrained from toothbrushing during 3 test periods and rinsed 15 x daily for 4 d with 10 ml of: (1) 50% palatinose, (2) 37.5% palatinose + 12.5% xylitol, or (3) 50% xylitol. A contrast period with no mouthrinses was also carried out. The 4 periods were carried out in a randomized order with a cross-over design. After the 4-day periods, 3 parameters were measured: (1) plaque pH during the first 30 min after a mouthrinse with palatinose, a mixture of palatinose and xylitol or xylitol alone, directly followed by a 2nd rinse with 10% sucrose; (2) number of mutans streptococci and lactobacilli in plaque and saliva; (3) plaque index. The most pronounced pH drop for the sugar substitutes was found when rinsing with 50% palatinose after the palatinose period, and the least pH drop with 50% xylitol after the xylitol period. The sucrose rinse gave similar pH fall after all 4 periods. The microbial data showed no differences between the 4 periods, but the mutans streptococcus counts in saliva decreased after the xylitol period in contrast to the 3 other periods. Regarding the plaque index, xylitol gave lower scores compared to the other 3 periods.

Longitudinal study of caries, cariogenic bacteria and diet in children just before and after starting school.

Fifty 5-yr-old preschool children living in Akranes, a small community in West Iceland known to have a high caries prevalence, were investigated with respect to caries, salivary counts of mutans streptococci and lactobacilli, and consumption of cariogenic foods. Fifteen months later, after being in school for half a year, 43 of the 50 children were reexamined and investigated as before. Mean dmfs scores rose from 7.1 to 9.0, but the scores including initial caries rose from 9.7 to 15.3. Mutans streptococci were carried by 84% of children on both occasions with a mean count 2.1 and 3.6 x 10(5) cfu/ml. Lactobacillus carriage increased from 29 to 38% and the mean count from 5.1 to 13 x 10(3) cfu/ml at 6 yr. The frequency of consumption of sugar-containing foods increased from 4.2 to 5.2 intakes per day and between-meal snacks rose from 3.0 to 3.7 per day. Children classified as "misusing" sugar were 59% at 5 yr and 83% at 6 yr. The mean caries score at 6 yr for children "misusing" sugar was 10.7 but only 2.0 for those not misusing sugar. Thus the deterioration in dental health appears, in these children, to be associated with the increased consumption of sweets and other cariogenic between-meal snacks after starting school.

Effect of partial substitution of invert sugar for sucrose in combination with Duraphat treatment on caries development in preschool children: the Malmö Study.

The aim was to study the effect of substitution of invert sugar for sucrose, in combination with fluoride varnish (Duraphat) treatment twice a year, on caries development in preschool children. One hundred and eighty-seven 4-years-olds were divided randomly into four sugar groups: (1) sucrose (S), (2) sucrose-Duraphat (SD), (3) invert sugar (I), and (4) invert sugar-Duraphat (ID). All families were asked to buy beverages, biscuits, breakfast cereals, marmalade, ice cream, jam, ketchup, sweets and table sugar, totally 32 different food items, sweetened with invert sugar or sucrose. The substitution was, thus, restricted to a number of sugar-rich between-meal products. The study was carried out double-blind for 2 years. The children of those parents who did not want to participate in the sugar groups were divided randomly into one of the following two groups: (5) Duraphat (D), and control (C). Because of lack of cooperation, only 114 of the 187 children (61%) were considered to have completed the study. The mean caries increment, including initial lesions, was 3.86 dmfs in the combined groups S and SD (n = 63) and 3.10 dmfs in the combined groups I and ID (n = 51) during the 2 years (p = 0.34). The corresponding values for the 2nd year only were 1.84 and 0.67 dmfs, respectively (p = 0.09). The mean caries increment was 2.86 dmfs in group D (n = 113) and 4.10 dmfs (p = 0.08) in group C (n = 93). If initial caries lesions were excluded from the index, the difference between groups D and C was significant (p = 0.008).(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of a model for short-term clinical testing of cariogenicity.

Conventional mirror and probe examination and laser fluorescence were used to score caries-like alterations on the buccal surfaces of posterior teeth in 60 panelists, allotted to one of three groups. All subjects refrained from oral hygiene for five days. In one group each subject consumed 12 sucrose candies daily between meals and in the second group each subject similarly consumed 12 palatinose (isomaltulose) candies. The third group served as a control. At the end of the experimental period the tooth surfaces reexamined. Conventional and laser fluorescence scoring techniques showed an increase in the number of caries-like alterations for all groups, but there were no significant differences between the groups. For all groups, the laser method gave significantly greater scores throughout. The findings imply that certain aspects of the early development of enamel caries in subjects regularly using fluorides must be considered in the design of a short-term cariogenicity test. It is concluded that sensitive quantitative methods for the registration of caries are necessary in such tests.

Secretion rate and buffer effect of resting and stimulated whole saliva in relation to general health.

The aim of this investigation was to study the possible relationship between general health and the salivary secretion rate and buffer effect. Based on the results of duplicate salivary tests, 92 consecutive dental patients with a very low secretion rate and/or buffer effect of resting and/or stimulated whole saliva were referred for a medical examination, which included blood and urine analyses. Various medical findings were made for 39 per cent of these patients. As comparison, the same medical and salivary variables were studied in 50 subjects who participated in medical screening programs. Medical findings were made for 32 per cent of the subjects, of whom only about one fourth had one or more very low salivary values. For both groups, no statistically significant difference was found for any of the variables studied when comparing individuals with and without medical findings. Therefore, the results obtained did not indicate a relationship between impaired health and a very low salivary secretion rate and/or buffer effect of whole saliva.

Effect of repeated intake of a sugar free fluoride-containing chewing gum on acidogenicity and microbial composition of dental plaque.

In a double blind cross-over study, 20 subjects were given either a sugar free chewing gum containing 0.25 mg fluoride or the same chewing gum without fluoride, eight times a day for 7 days. The pH of 3-day-old plaque was determined before and after each experimental period following a 30-s mouth-rinse with 10 ml 15% sucrose. The pH-decrease was significantly less pronounced after using the fluoride gum than after the placebo gum (P less than 0.001). In a second study, 20 subjects participated in a similar study. In this experiment the acid production activity from sucrose in dental plaque in vitro was determined with the aid of a titration method. In addition, the dental plaque wet weight and the total number of cultivable organisms, Streptococcus mutans and lactobacilli, expressed as the number of colonies per mg plaque, were determined. No significant effect was found on any of these parameters after using the fluoride gum compared to the placebo gum. Thus, the results indicate that slightly elevated levels of fluoride in saliva during daytime, achieved by repeated intake of fluoride gums for 7 days, are sufficient to influence the acidogenicity of dental plaque in vivo.

Palatinose--a sucrose substitute. Pilot studies.

Pilot studies on isomaltulose, (Palatinose), a sucrose substitute, including acid production in plaques, acid production in suspensions of dental plaque material or of Streptococcus mutans were performed, as well as studies on the effect of isomaltulose on glucan synthesis, by Strep. mutans. Also an experimental caries study in the rat was carried out in a few animals. The results indicated that isomaltulose is only slowly fermented in the oral cavity and that glucan formation from isomaltulose, if any, is very small. Sulcal caries only was found in rats challenged with isomaltulose. Since the animals developed very well on the isomaltulose diet and did not have stomach disorders, isomaltulose is considered to be of great interest as a sucrose-like, low-cariogenic and nontoxic sucrose substitute.

Cariogenicity of isomaltulose (palatinose), sucrose and mixture of these sugars in rats infected with Streptococcus mutans E-49.

Each of three groups of Wistar rats, 19-20 animals per group, was fed an experimental diet containing either (1) isomaltulose 56%, (2) sucrose 56%, or (3) a mixture of isomaltulose and sucrose (17.5% + 38.5%). The animals were infected with Streptococcus mutans E-49 and one half of the animals was kept on the diet for 8 weeks and the other half for 14 weeks. Only sulcal caries was found in the isomaltulose animals after 8 weeks and 14 weeks. the group fed sucrose had high numbers of carious bucco-lingual, proximal and sulcal surfaces. The group fed the mixture of sucrose and isomaltulose had fewer lesions than the sucrose group on bucco-lingual surfaces after the 8 week experiment (P less than 0.01) and fewer bucco-lingual and proximal surfaces (P less than 0.01) after the 14 week experiment.

Interaction between xylitol and sorbitol in plaque metabolism.

Xylitol and sorbitol, when metabolized by microorganisms, are transported through the cell membrane and phosphorylated by membrane-bound phosphoenolpyruvate-dependent phosphotransferase systems. Sorbitol-6-phosphate may be oxidized by a sorbitol-6-phosphate dehydrogenase to fructose-6-phosphate and further decomposed in the Embden-Meyerhof pathway. Xylitol-5-phosphate - if not metabolized - may be toxic to the cell. There are few specific pathways known for xylitol metabolism in microorganisms. Due to structural resemblance between the xylitol and the sorbitol molecules interaction between xylitol and sorbitol metabolism is likely to occur. Xylitol - although only slowly taken up by plaque and oral microorganisms - may reduce plaque formation and cause an increase in plaque pH. Evidence for a phosphotransferase system for xylitol has recently been demonstrated in Strep. mutans, which may cause accumulation of xylitol-5-phosphate in the cell. Some studies carried out by the author and associates on acid production in the oral cavity from cell. Some studies carried out by the author and associates on acid production in the oral cavity from sorbitol in the presence of xylitol in chewing gum containing sorbitol reduces acid production from sorbitol. This may be explained by the following effects of xylitol: Reduction of plaque and the number of microorganisms on the teeth. This is thought to be a consequence of the toxic effect of xylitol-5-phosphate. Inhibition of acid production from sorbitol. This is believed to be a consequence of competitive blocking of the phosphotransferase system due to structural similarities between xylitol and sorbitol.

Effects of xylitol on the acid production activity from sorbitol by Streptococcus mutans and human dental plaque.

-A method for the determination of acid production from 20-25 mg (wet weight) of Streptococcus mutans and 12-33 mg (wet weight) of human dental plaque is described. After endogenous acid production had been followed, either sorbitol or xylitol or a mixture of sorbitol and xylitol (2:1) was added. After about ten minutes glucose, sucrose or Palatinose were added for a vitality test. Addition of xylitol to the bacterial suspension caused inhibition of acid production from sorbitol by Streptococcus mutans grown on sorbitol or a mixture of sorbitol and glucose. It was also observed that it had a similar effect on acid production from sorbitol in suspensions of dental plaque with few exceptions. On the other hand, Streptococcus mutans cells grown on glucose, sucrose and xylitol media, produced no or insignificant amounts of acid from sorbitol. Streptococcus mutans cells grown on media containing glucose, sucrose, sorbitol and a mixture of sorbitol and glucose generally formed a large amount of acid from glucose and sucrose after the addition of sorbitol and xylitol. However, Streptococcus mutans cells grown on a medium containing xylitol and the mixture of sorbitol and xylitol formed less acid from glucose. The acid production activity from sorbitol in suspensions of dental plaque after the xylitol addition was somewhat lower than the acid production from sorbitol alone (p less than 0.02).

Caries increment in primary teeth after application of Duraphat fluoride varnish.

In order to evaluate the possible cariostatic effect of a fluoride varnish in the primary dentition, Duraphat varnish was applied twice yearly for 2 years to the teeth of 195 3 1/2-year-old children of both sexes attending nine preparatory schools in the Warsaw area. A control group of 127 children attending nine other preparatory schools was also examined. For each child a dmfs1 index (including "caries without macroscopic defect") and a dmfs2 index ("caries without macroscopic defect" excluded) were determined as well as a dmft1 and a dmft2 index. After 2 years the difference between the test and the control groups regarding the mean dmfs1 and dmft2 index increments was 9.39% (P greater than 0.1) and 24.09% (P less than 0.05), respectively. No significant differences were found, however, concerning the dmft2 and dmfs2 indices, the percentage children with new gingival caries, the number of teeth extracted on account of caries and the number of remaining teeth. A test group of 46 children treated with fluoride varnish in which a complete radiological examination could be carried out before and after the experimental period and which was treated with fluoride varnish was compared with a similar group of 27 children, which was not treated with fluoride varnish. The differences in caries increments were small, less than 15%, and were not significant. Taking into consideration the great variation between the schools it was concluded that the cariostatic effect of Duraphat application twice yearly in the primary dentition of these children was slight.

The effect of fluoride on the acid production of Streptococcus mutans and other oral streptococci.

The influence of fluoride on the acid production of streptococcal strains was examined using an established method for the determination of acid production by microorganisms. The inhibitory effects of fluoride on acid production increased when the pH dropped from 5.5 to 4.0. A concentration of 5 ppm fluoride inhibited the acid production activity of Streptococcus mutants at pH 5 and below. Susceptibility to fluoride varied among streptococcal strains. These results suggest that fluoride in dental plaque may affect acid production below pH 5.5.

A colourimetric screening test for evaluation of the buffer capacity of saliva.

A colourimetric method for screening buffer capacity of mixed paraffin stimulated saliva in general practice is described. Mixed paraffin stimulated saliva (1.00 ml) is pipetted into a standard tube belonging to a commercial "saliva kit" (Dentobuff, Orion Diagnostics Ltd). The tube is sealed with a plastic stopper and vigorously shaken for 10 seconds. The stopper is then removed and carbon dioxide is allowed to evaporate for 2--5 minutes. The colour is compared with a scale graded from pH 3 to pH 6. The method was evaluated using 136 dental patients and dental students, and a number of dentists and nurses, and the results were compared with the generally accepted clinical method developed by Ericsson (1959). Several different nurses, dentists and dental students took part in registering the results. In four cases the results differed by more than +/- 2.0 pH units between the two methods and in another 18 by more than +/- 1.0 units. Of the 80 tests performed on no occasion was a person with a "low" salivary buffer capacity evaluated as "normal" or "good". There was no obvious systematic deviation between the two methods, provided carbon dioxide was allowed to evaporate for 2--5 minutes before reading the colour. A thorough examination revealed that at a final pH over 5.5 the method gives lower values than Ericsson's method because of retained carbonic acid, a fact which was considered to be of minor importance, clinically. The method was found to be easy to handle and rapid and the accuracy was considered adequate. It is advisable, however, to repeat the test once or twice because of biological variation and in doubtful cases if "intermediate" results are repeatedly found to send the patient to a clinic with facilities for a complete test.