The effect of saliva on the formation of KOH-soluble fluoride after topical application of amine fluoride solutions of varying fluoride concentration and pH.

The effect of saliva on the amount of KOH-soluble fluoride formed on a sound enamel surface after application of amine fluoride solution of varying fluoride concentrations (1, 0.5 and 0.25% F) and pH (5.3, 4.5 and 4.0) was examined in an in vitro study. The saliva pretreatment increased the amount of KOH-soluble fluoride at the highest pH value. For any given fluoride concentration, the presence of saliva did not influence the amount of KOH-soluble fluoride. These data suggest that saliva could enhance the amount of KOH-soluble fluoride if the topical fluoride preparations are not highly acid.

In vitro fluoride uptake by enamel from different amine fluoride concentrations.

The aim of this in vitro study was to examine whether the concentration of amine fluoride solution influences the uptake of fluoride by enamel after topical treatment. Four slabs were prepared from each of 31 impacted third molars and selected at random so that one slab from each tooth was present in each group. One group of slabs served as an untreated control (D). The slabs of the other three groups were shaken for 3 min in an amine fluoride solution on 3 successive days: group A (1% F), group B (0.5% F) and group C (0.25% F). The amounts of KOH-soluble fluoride produced with 1 and 0.5% amine fluoride solution did not differ significantly and were superior to 0.25% amine fluoride solution. A statistically significant increase in structurally bound fluoride was observed in groups A, B and C compared with control group D. The difference in the amounts of structurally bound fluoride was significant only between 1 and 0.25% F concentrations. These data suggest that the fluoride content in an amine fluoride solution (1%) can be decreased by half without reducing its ability to form alkali-soluble or structurally bound fluoride. The results of this study are consistent with those of previous clinical studies.

Current concept on the anticaries fluoride mechanism of the action.

The paper discusses a possible new concept of the role of fluoride and its mechanism of action in caries prevention. In the past fluoride inhibition of caries was ascribed to reduced solubility due to incorporation of fluoride (F) into the enamel minerals (firmly bound fluoride or fluorapatite). Based on the new findings, it appears that fluoride, either released into or present in the fluid phase bathing the hard tissue, is more important for the reduction of caries development and progression. There is convincing evidence that fluoride has a major effect on demineralization and remineralization of dental hard tissue and that it interferes with acid production from cariogenic bacteria. The provision of dissolved fluoride is the key to successful therapy. The source of this fluoride could either be fluorapatite or calcium fluoride (CaF2) (like) precipitates, which are formed on the enamel and in the plaque after application of topical fluoride. The precipitates of calcium fluoride do not dissolve quickly as was initially believed. Calcium fluoride coating at neutral pH by pellicle proteins and phosphate is the main reason for this. The dissolution of the fluoride from calcium fluoride is pH dependent. At lower pH, the coating is lost and an increased dissolution rate of calcium fluoride occurs. The CaF2, therefore, act as an efficient source of free fluoride ions during the cariogenic challenge. These are subsequently incorporated into the enamel as hydroxyfluorapatite or fluorapatite.

Effect of amine fluoride on enamel surface morphology.

In this in vitro study, examination of the enamel surface morphology after topical application of an amine fluoride solution with different fluoride (F) content was carried out. Sound human enamel slabs were treated with an amine fluoride solution containing either 1.0, 0.5 or 0.25% F for 3 min. during 3 days. All slabs were examined using scanning electron microscopy and energy-dispersive spectroscopy (SEM/EDS) qualitative analysis. The globular precipitates were revealed in all treated specimens, regardless of F content. The distribution of the deposits was more homogeneous in groups treated with higher concentrations; however, the globules were larger and more cubical in groups treated with lower fluoride concentrations. These larger globules could be less soluble and thus serve as a fluoride reservoir for a more extended period and so they could contribute to the caries preventive effect in professional topical products with lower fluoride concentration. Following the 24-hour treatment with KOH the precipitates could be removed; however, the enamel surfaces covered with the precipitates were less degraded than the untreated enamel. The EDS qualitative analysis showed that the intensities of fluoride signals were increased with the higher concentration of fluoride in an amine fluoride solution, while the intensities of calcium signals were decreased. The enamel surface precipitates were alkali-soluble, but we were not able to demonstrate that they are pure calcium fluoride.

Anticaries effect of different amine fluoride concentrations in schoolchildren.

A double-blind 3-year clinical trial was conducted in a nonfluoridated water community in which 354 schoolchildren aged 9-10 years were assigned randomly to three groups (A, B and C) and subjected to a treatment with 1 of 3 different concentrations of amine fluoride solution every 2 months. Clinical examinations were conducted at baseline and after 1, 2, and 3 years. For group A (positive control) receiving topical applications of amine fluoride solution (1%), the 3-year DMFT and DMFS increments were 4.0 +/- (SD) 2.7 and 8.5 +/- 5.6, respectively. For group B (0.5% F), the DMFT and DMFS increments were 4.4 +/- 3.0 and 8.4 +/- 5.7, respectively; these differences being statistically not significant. The mean caries increments in group C (0.25% F) were 5.1 +/- 2.9 for DMFT and 10.0 +/- 5.5 for DMFS. The differences in incremental caries scores between group C and groups A or B were statistically significant (p < 0.05). Thus, the amine fluoride solution, in which the fluoride content was reduced by half, provided similar caries reductions in schoolchildren as did a standard amine fluoride solution with 1.0% F.

Caries-preventive effect of two different topical fluoride concentrations with two different frequencies of application in preschool children.

The effects of standard topical amine fluoride solution (1% F) and a low-fluoride solution (0.5% F) with two different frequencies of application (5 and 10 times a year) on 2 years dental caries increment were compared in a double-blind clinical trial involving 199 kindergarten children. The results suggest that increased frequency of application of a low fluoride topical solution (10 times a year) may provide caries protection in preschool children with relatively high caries activity.

[Dentist's patient under antineoplastic therapy]. / Stomatoloski pacijent pod antineoplasticnom terapijom.

The side effects of antineoplastic drugs can be manifest in the oral cavity. Every dentist must be familiar with these groups of drugs and their mechanisms of action and the management of their adverse oral manifestations. The most common oral reactions to administered antineoplastic drugs are: mucositis, local or generalized infections and hemorrhages. The right way in which these manifestations may be handled therapeutically can ensure dentist's patient a langer life of better quality.

[Topical fluorides--possible side effects]. / Topikalna fluoridacija--moguci nepozeljni ucinci.

The use of topical fluoride products is established as an effective method in caries prevention and might be a considerable extra source of fluoride. Following the use of topical fluoride products variable amounts of fluoride are swallowed and adsorbed into the systemic circulation, amounts which may be sufficient to produce some effects on physiologic and biochemical processes like dental fluorosis, changes in the structure and function of the gastric mucosa, kidney function and plasma and tissue cAMP levels. These possible side effects are all, except that of dental fluorosis, transient and reversible. For the purpose of enhancing the safety of topical fluoride application, several recommendations are mentioned all of which are designed to reduce the ingestion and absorption of fluoride.