Heikki Luoma

A simultaneous reduction of caries and gingivitis in a group of schoolchildren receiving chlorhexidine-fluoride applications. Results after 2 years.

A total of 164 schoolchildren, aged 11–15 years with high DMF scores was divided into 4 groups. Subjects of the CXF group brushed their teeth after school lunch and rinsed their mouths with a solution containing 0.05% chlorhexidine gluconate + 0.044% NaF in succinic acid/NaOH buffer, pH 5.9. The F group had 0.044% NaF in the buffer. The PI group used a placebo solution and the C group served as the basic control. Respective nonabrasive toothpaste preparations were used in the evenings and twice a day during weekends and the holidays. After 2 years, the mean DMFS increments in the C, Pl, F and CXF groups were 6.3, 5.1, 4.3 and 2.9, respectively. The percentage of subjects with bleeding vestibular gingival units examined in different groups had changed from initial to final value as follows: C, 40–63; PI, 50–49; F, 71–47 and CXF, 63–14.

Post-treatment Effect of Fluoride Varnishes in Children with a High Prevalence of Dental Caries in a Community with Fluoridated Water

Children with a high prevalence of dental caries living in a community with fluoridated water had received semi-annual half-mouth applications of one of two fluoride varnishes for three years. Two years after the applications were discontinued, we studied the post-treatment effect of the varnishes. The absolute reduction in caries found during the treatment was retained, but the cariostatic effect did not continue after treatment. This finding suggests that fluoride varnish applications should not be discontinued after three years.

Effect of Chlorhexidine-Fluoride Applications Without and With Sr and Zn on Caries, Plaque, and Gingiva in Rats

Molar teeth of four groups of Osborne-Mendel rats, kept on a cariogenic dict, were treated once per day for 48 days with either distilled water (solution C), a solution containing 0.05% chlorhexidine gluconate and 0.04% NaF, pH 5.8 (solution CXF), CXF plus 1000 ppm Sr (solution CXFS), or CXFS plus 1000 ppm Zn (solution CXFSZ). Caries of the hemi-sectioned lower molars was scored according to grades of severity, and the extent of the buccal plaque was estimated. Inflammatory cell infiltration, vascularity, and thickness of the oral mucosa were estimated from stained sections of the buccal oral mucosa to detect possible adverse effects of the treatments. Fissure caries lesions with involvement of the dentin were reduced by 57% (p < 0.01) with the CXF treatment and by 68% (p < 0.001) with the CXFS treatment. The CXFSZ treatment reduced the fissure caries least (44%, p < 0.05), but it appreciably reduced the extent of plaque. The mucosal changes were greatest in the group receiving the CXFSZ treatment, but they were generally small and at a non-pathological level. Supplementation of the CXF solution with Sr thus appeared beneficial for caries reduction.

Phosphorus Translocation between Enamel and Streptococcus mutans in the Presence of Sucrose and Fluoride with Observations on the Acid Phosphatase of S. mutans

Intact cells of Streptococcus mutans K-1 were incubated with enamel powder in buffer, pH 5.8, saturated with enamel salts, the cells or the enamel having been previously labelled wi

Participation of Phosphate of Bacterial Origin in the Phosphate Exchange and Rehardening of the Enamel and the Modifications by Fluoride, Chlorhexidine and Propanol

Washed cells of the FA-1 and K-1 strains of Streptococcus mutans were incubated in buffered solutions, pH 5.9, that were initially either saturated or slightly undersaturated by add

The effect of different strontium concentrations on the efficacy of chlorhexidine-fluoride-strontium gel in preventing enamel softening in vitro

The effects were compared of strontium concentrations of 0, 15, 50 and 250 parts/10(6) in chlorhexidine(0.20%)-fluoride(0.16%) gel in preventing the softening of bovine enamel during bacterial fermentation. Fresh Streptococcus sobrinus cells were suspended in a buffer solution (pH 6.0) with 3.3% sucrose and centrifuged as a plaque-like layer on the top of enamel slabs covered with 10 microliters gel. AFter 24 h incubation, the pH fall of the fluid was significantly smaller in all test groups than in the placebo group. Strontium seemed to have an inhibitory effect on the pH fall. All test gels significantly prevented softening and dissolution of enamel during bacterial fermentation, which was directly related to strontium concentration. The amounts of calcium and phosphorus in the cells and fluid after incubation were the smallest in the group with 250 parts/10(6) strontium. In a second experiment without bacteria, new enamel slabs were covered with 10 microliters gel containing chlorhexidine and NaF with 0 and 250 parts/10(6) strontium to study the protective effect of strontium. After 24 h gel treatment, each enamel slab was dissolved in 1 ml 0.1 M lactic acid, pH 5.0, for 2 h. Significantly less calcium and phosphorus were dissolved from the enamel in both test groups than in the control and placebo groups. However, the placebo gel also prevented calcium and phosphorus dissolution significantly. These results suggest that the addition of strontium to chlorhexidine-fluoride gel improves the ability of this combination to prevent caries-like enamel softening. The inhibition of bacterial acid production by the strontium-containing gel may explain this enhanced protection of enamel.

Caries reduction in rats by phosphate, magnesium and fluoride additions to diet with modifications of dental calculus and calcium of the kidneys and aorta.

To elucidate further our previous findings on the corrective effects of dietary magnesium, phosphate and fluoride additives on the disturbed calcium phosphate balance of the body, including caries, the experimentation was continued by varying the basal diet and the concentration of the additives. Addition of orthophosphate alone to a magnesium-deficient cariogenic diet strongly reduced fissure caries. This was accompanied by an appreciably reduced rate of growth. Phosphate addition per se also promoted both renal and aortic accumulation of calcium as well as accumulation of dental calculus. These undesirable effects of phosphate could be reduced or prevented by further addition of magnesium or fluoride or preferably by both simultaneously. All three additives together reduced fissure caries significantly. During low or medium basal dietary intake of magnesium, the fluoride, when fed with phosphate, reduced caries significantly too, but this could not fully correct phosphate-induced renal calcium accumulation. The additional presence of magnesium was necessary for the full correction of the renal calcium content. Aortic calcium was increased by phosphate in magnesium-deficient rats but it was corrected by fluoride. Phosphate-induced dental calculus accumulation was reduced by fluoride and magnesium together on a high-magnesium basal diet. The results suggests a possibility of preventing the mineral disequilibrium of the body, i. e. demineralization of hard tissues and mineralization of soft tissues through some simple alterations in food composition.

Bovine enamel hardness and its Ca-, P-, Mg- and F-contents modified by the bacterium Streptococcus mutans, artificial dental plaque and fluoride

A layer of cells from buffered Strep. mutans suspension (pH 5.8), with or without sucrose, was centrifuged on bovine enamel surfaces. Fluoride was added to a part of the samples (final F 25 parts/10(6]. Control and test samples were incubated at 37 degrees C for 18 h. The pH of the fermenting plaque dropped to 4.15. When F was present, the final pH was 4.45. Microhardness of the enamel surface was reduced by the presence of sucrose but less in the presence of F. Enamel Ca was liberated during fermentation, but only into the fluid and less in the presence of F. The weight ratio of Ca and P released by sugar fermentation was 3.14 and 1.91 when F was present. The F content of enamel surface was only slightly increased (130 parts/10(6]by the F in distilled water alone. Subsurface enamel gained more F (280 parts/10(6]. When artificial plaque was present, addition of F increased the F content of enamel surface by 450 parts/10(6) and F of subsurface by 210 parts/10(6). The addition of F increased the enamel F content to the greatest extent under the fermenting plaque, 680 parts/10(6) in surface and 400 parts/10(6) in subsurface enamel, compared to the values of the enamel under non-fermenting plaque.

The Effect of a Bicarbonate-Phosphate Combination, without and with Fluoride, on the Growth and Dental Caries in the Rat

A total of 49 rats was littermate-distributed into three dietary groups when 21 days old. The control group (C) was fed a cariogenic nutritionally adequate high- sucrose diet for 40 days. The second group (BP) received the same diet as group C except that 4% of the sucrose component of the diet was replaced by a combination Phosphate, dietary NaHCO3 + KH2PO4 (mole ratio 9.82/1). The third group (BPF) was fed the same diet as group BP except that NaF was also added to the sucrose to give 10 ppm F addition to the whole of diet. The mean gain of body weight in the BPF group was 55% higher than in group C (p

Exchange of fluoride between bovine enamel and the surface-related cells of the oral bacterium Streptococcus mutans

Standard areas of intact bovine enamel surface were fluoridated with dental F-varnish for 24 h and then cleaned from varnish residues and thoroughly rinsed with distilled water. Sucrose fermentation by a plaque-like layer of Streptococcus mutans cells covering such an enamel surface was accompanied by a rapid but transient accumulation of F of enamel origin by the Strep. mutans cells and by a pH drop in the plaque to pH 4.0. The uptake of F from the surface by the control cells, utilizing their carbohydrate stores and causing a smaller pH-drop, was slow but no release of F back to the cell exterior took place within 18 h. In a second experiment, F- varnished and placebo- varnished bovine enamel granules were used as above, but they were not thoroughly washed after being varnish-treated and cleaned. Both the sucrose-fermenting and the control layer of Strep. mutans rapidly released appreciable but equal amounts of fluoride from the F-treated enamel. The accumulation of F of enamel origin by the Strep. mutans cells with or without sucrose was rapid and of almost the same magnitude. In the model with the sucrose-utilizing Strep. mutans and the F-treated enamel granules, the plaque pH-drop was less and the dissolution of the enamel Ca and P completely prevented compared to the respective changes in the sucrose-utilizing model with placebo-treated enamel granules.