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Biomedical subjects

C J Spak

Publications and source records attributed to C J Spak.

17 recordsLinked to original sources
PubMed1994

Caries incidence, salivary flow rate and efficacy of fluoride gel treatment in irradiated patients.

The caries-preventive effect of daily applications of a fluoride gel was studied in 55 patients receiving radiotherapy for tumors of the head and neck. The study was designed as a randomized, double-blind study with two parallel groups. From the start of radiotherapy one group received a 0.42% F gel once a day for 1 year. The other group received a daily application of a 1.23% F gel for 4 weeks followed by the use of the 0.42% F gel daily for 1 year. The results showed that in patients with an unstimulated saliva flow of > 0.1 ml/min daily fluoride gel treatment with a fluoride concentration of 0.42% F was sufficient to inhibit caries almost completely. The use of the 1.23% F gel was not superior to the 0.42% gel treatment program alone. In an attempt to evaluate the salivary flow rate as a diagnostic criterion for increased caries risk, sensitivity and specificity were evaluated. It was found that with an unstimulated saliva flow rate of < 0.1 ml/min the positive predictive value was 80%. The corresponding value for stimulated salivary flow rate of < 0.5 ml/min was 85%. One can therefore predict that 80% of patients with flow rates < 0.1 ml/min will develop at least one carious lesion per year. The corresponding negative predictive value for unstimulated saliva flow > 0.1 ml/min was 75%. That means that 75% of patients using the 0.42% F gel daily and with at least some saliva secretion will not develop any new carious lesions.

Dental Caries↗
PubMed1991

Caries-inhibitory effect of titanium tetrafluoride in rats.

The purpose of this study was to evaluate the caries-inhibitory effect of TiF4 as compared with equimolar solutions of neutral and acidified NaF. Sixty Sprague-Dawley rats were weaned 19 days after birth and given a cariogenic diet. They were randomly divided into four groups and given a 1-min topical treatment of the molar teeth on day 1 and day 17 of the experiment with the following solutions: group 1: 1% TiF4, pH 1.5; group 2: 1.3% NaF, pH 7.0; group 3: 1.3% NaF, pH 1.5; and group 4: control, distilled water. From day 2 the rats were inoculated with Streptococcus mutans twice weekly. On day 55 the rats were killed, and caries scored in accordance with Keyes. Total caries scored were (mean +/- SD): group 1, 12.7 +/- 9.5; group 2, 17.4 +/- 8.6; group 3, 14.3 +/- 9.7; and group 4, 29.5 +/- 9.0. There were significantly (p less than 0.05) reduced caries scores for total caries and for buccal + lingual and sulcal areas for all test groups as compared with the control group. Differences between control and test groups in proximal surfaces and between fluoride groups were non-significant. The results showed that the caries-inhibitory effect of TiF4 is at least as good as that of NaF in rats.

Animals↗
PubMed1991

The effect of a chewing gum on salivary secretion, oral mucosal friction, and the feeling of dry mouth in xerostomic patients.

A new chewing gum (PTC) with the ability to release flavoring substances for a rather long time was tested for its ability to stimulate saliva secretion. The chewing gum is mildly flavored and contains non-cariogenic sweeteners (xylitol and sorbitol). Measurements of saliva secretion rate and oral mucosal sliding friction and subjective evaluations on visual analog scales were made in relation to chewing and compared with those when chewing a commercially available gum (V6). The study was a randomized, crossover comparison with blind evaluation. Both chewing gums stimulated saliva secretion and decreased oral mucosal friction. The PTC gum gave consistently higher mean values of saliva secretion rate and lower oral mucosal friction values than V6. The difference was statistically significant for the saliva secretion rate and most pronounced after 5-10 min of chewing. There was also a statistically significant difference between the subjective evaluations of V6 and PTC with regard to saliva-stimulating ability and taste in favor of the PTC gum.

Aged↗
PubMed1990

Fluoride pharmacokinetics: its implications in the fluoride treatment of osteoporosis.

This report reviews some aspects of fluoride pharmacokinetics in relation to the treatment of osteoporosis. The bioavailability of conventional plain NaF tablets has been shown to be close to 100, for sustained-release NaF tablets close to 90%, and for enteric-coated NaF tablets 65%. The simultaneous intake of food and/or calcium tablets reduces the bioavailability by 30 to 40%. Fluoride renal clearance is influenced by both urinary pH and flow and the clinical consequences of this is discussed. Studies on plasma kinetics of fluoride during chronic fluoride intake suggests that a plasma sample taken at mid-dosage intervals will give reproducible "mean steady-state" levels. It is suggested that improvements of the clinical benefit of fluoride therapy in osteoporosis might be achieved if the dosage regimen were based on the pharmacokinetic properties of the fluoride preparation used as well as plasma fluoride monitoring.

Biological Availability↗
PubMed1990

Studies of human gastric mucosa after application of 0.42% fluoride gel.

Dental prophylaxis with APF gels (1.23%) may cause gastric distress as a side-effect. This gastric irritation is probably due to a direct toxic effect of fluoride (F), swallowed in conjunction with the treatment, on the gastric mucosa. The aim of the present study was to investigate whether--and to what extent--a dental treatment with 3 g of a 0.42%-F gel could affect the gastric mucosa due to inadvertent swallowing of the gel. Ten subjects underwent a control gastroscopy, and two weeks later, a second gastroscopy was performed two h after a F gel treatment. During the gastroscopy, the mucosa was examined and the injuries graded according to an arbitrary scale. Four biopsies of the antral and corpus regions of the stomach were taken and evaluated histologically. The mean (+/- SD) amount of F retained after the application was 5.1 +/- 2.1 mg, i.e., 40% of the applied amount of F. Petechiae and erosions were found in the mucosa in seven of the ten patients. The histopathological evaluation revealed changes in nine of ten patients, with the surface epithelium as the most affected component of the mucosa. The present study clearly shows that a treatment with a F gel of rather low F concentration may result in injuries to the gastric mucosa. The importance of current recommended guidelines so that the amount of F swallowed during a gel application can be minimized is emphasized. From a toxicological standpoint, the use of a low-F gel instead of a 1.23%-F gel in small children is recommended for avoidance of adverse gastric effects.

Binomial Distribution↗
PubMed1990

Pharmacokinetics of fluoride in man and its clinical relevance.

A large number of parameters will influence and mediate the activity and the pharmacological response of dental fluoride products after systemic or topical treatment. This report reviews some aspects of the pharmacokinetics of fluoride in man, fluoride bio-availability, plasma kinetics, and kinetics of fluoride in saliva and plaque fluid. Pharmacokinetic studies in growing dogs show that 90% of a single injected fluoride dose is retained shortly after birth, but at maturity it decreases to about 50%. The degree of fluoride accumulating in calcifying tissues seems to be strongly related to age. The bio-availability of fluoride from swallowed fluoride toothpaste is shown to be decreased if the toothpaste is ingested close to a meal. Several studies show that fluoride exerts its cariostatic effects through the liquid phase surrounding the enamel. The importance of fluoride in the fluid environment of the teeth and the kinetics of fluoride in saliva are discussed. Clinical studies using different slow-release fluoride systems indicate that they are promising cariostatic agents--in particular intra-oral slow-release devices and lozenges. A new micro-analytical method to study the kinetics of fluoride in plaque fluid collected from single tooth sites has been developed. Preliminary studies show that the clearance of fluoride from plaque fluid is slowest in the upper incisor region, followed by the molar region, and faster in the lower incisor region. A site-by-site study of the concentration of fluoride in plaque fluid after topical fluoride administration could be extremely beneficial in optimization of the methods and recommended safety regimens for fluoride therapy.

Biological Availability↗
PubMed1985

Renal clearance of fluoride in children and adolescents.

Renal function and fluoride excretion have been studied in 38 children. The children were divided into three groups according to their glomerular filtration rate: normal (92 to 136 mL/min/1.73 m2 of body surface area [BSA]), low (less than 92 mL/min/1.73 m2 BSA, and super-normal (greater than 136 mL/min/1.73 m2 BSA). Standard clearance technique with infusion of inulin and p-aminohippuric acid during water diuresis was used. Mean renal fluoride clearance was 45.0 +/- 9.8 (SD) mL/min in the group of children with normal glomerular filtration rates and 31.4 +/- 8.8 mL/min in the group with low glomerular filtration rates. This difference was statistically significant. There was a close linear relationship between renal fluoride clearance and glomerular filtration rate, urinary flow, and free water clearance. The fractional fluoride excretion did not differ between the groups. About 60% of the filtered fluoride was reabsorbed. No evidence for tubular secretion exceeding the reabsorption could be found. The results suggest that children have lower renal fluoride clearance rates than adults and indicate that a moderate impairment of the renal function could lead to increased retention of fluoride.

Adolescent↗
PubMed1983

Fluoride in human milk.

Reported contents of fluoride (F) in human milk vary considerably. The aim of this study was to determine the F content in human milk under different levels of F intake using a siliconfacilitated microdiffusion technique, which had a good accuracy and precision. The mean F concentration of colostrum from mothers in a 1.0 ppm and a 0.2 ppm F area was 0.36 +/- 0.02 mumol/l (+/- SEM) and 0.28 +/- 0.02 mumol/l, respectively. The mean F concentration of mature milk from a 1.0 ppm F area was 0.37 +/- 0.04 mumol/l. Within the 1.0 ppm F area, the intra- and interindividual differences in F concentration were very small. No statistically significant difference in milk F concentration between the two areas was found. Consequently, breastfed infants living in a 1 ppm or a 0.2 ppm F area will have an approximately equal F intake of 5-10 micrograms per day, in spite of great differences in F intake among the nursing mothers.

Circadian Rhythm↗
PubMed1982

Renal clearance of fluoride in a steady state condition in man: influence of urinary flow and pH changes by diet.

In order to study fluoride renal clearance, four subjects were given 3 mg fluoride as sodium fluoride tablets every 6 hrs for 60 hrs during two separate periods - during production of acid urine induced by a protein rich diet and during production of alkaline urine obtained by giving a vegetarian diet. Plasma and urine were collected every third hour for 72 hours during each experiment. In the protein rich diet period urinary pH was significantly lower than when the subjects were maintained on the vegetarian diet. Lower urinary output of fluoride during the protein rich diet experiment was recorded, however, the difference was not significant. Plasma fluoride at steady state was almost the same during both experiments. Renal fluoride clearance was significantly correlated to urinary pH in both types of experiments. When renal fluoride clearance was plotted versus urinary flow, the correlation was only significant during alkaline conditions. The average renal clearance was not significantly different between the two sets of experiments. It may be concluded, that pH and diuresis both influences fluoride renal clearance. Moreover, the results suggests that dietary components as such, influence renal clearance of fluoride in some way or another.

Adult↗