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Biomedical subjects

H Luoma

Publications and source records attributed to H Luoma.

At least 55 records · Page 3Linked to original sources
PubMed1984

Reduction of the lethality and the nephrocalcinotic effect of single fluoride doses by magnesium in rats.

Magnesium chloride, administered by gavage to fasting young rats, 30 min prior to sodium fluoride, elevated the LD50 for fluoride from 76 to 104 mg/kg body wt. The LD50 was elevated to greater than 180 mg/kg when magnesium was given in a dose equivalent to 2 or 3 times that of fluoride. In two experiments, a dose of 50 mg F/kg caused a mean 14- and 19-fold increase above the level of the control animals in the renal calcium content. The nephrocalcinotic effect of fluoride was nearly completely prevented by administering magnesium in a dose which is 3-fold the equivalent of the fluoride dose 30 min prior to fluoride.

Animals↗
PubMed1983

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.

Animals↗
PubMed1983

Risk of myocardial infarction in Finnish men in relation to fluoride, magnesium and calcium concentration in drinking water.

To study the influence of drinking water composition on the risk of myocardial infarction, the following study was conducted: The cases (C), men 30-64 years of age, had been discharged with a first acute myocardial infarction (AMI) from Kotka Central Hospital. The hospital controls (HC), matched for age and type of community, were selected for each case among surgical patients. Population controls (PC), matched for age and municipality, were drawn for each case from the population register. Subjects submitted a sample of their drinking water and a filled-in questionnaire. After exclusions, a series of 50 C-HC and 50 C-PC pairs was finally constructed. The point estimate of relative risk (RR) for the association between low F (less than or equal to 0.1 ppm) and increased risk of AMI was 3.0 in the C-HC series. In the C-PC comparison, RR was 4.4 RR for low Mg (less than or equal to 1.2 ppm) was 2.0 in the C-HC comparison and 4.7 in the C-PC comparison. The results are consistent with the hypothesis that both a low F and a low Mg intake are conducive to atherosclerosis leading to AMI.

Adult↗
PubMed1983

Effect of a sodium fluoride varnish on the progress of initial caries lesions.

Effect of applications of a sodium fluoride varnish, Duraphat, on progress of initial caries lesions was studied in 11-13-year-old children. All 60 children included in the study had high caries activity and life-long exposure to fluoridated drinking water. The varnish was applied semiannually using the half mouth technique, and annual clinical and radiographic examinations were made for 3 years. The treatment had little effect on the progress of initial caries lesions present before the first application of varnish. The progress of caries lesions formed during the study was inhibited more distinctly, and the difference between test and control side in the rate of progress of caries lesions was highly statically significant. Use of fluoride varnish seems to help prevent further development of early caries lesions.

Adolescent↗
PubMed1983

Arrestment of caries in rats by adding fluoride and magnesium to the diet.

90 weanling Osborne-Mendel rats were divided into six groups of 15 animals each. Half of them received a modified MIT 200 control diet in which one third of the sucrose of the original formula was replaced by high-extraction wheat fluor, magnesium content reduced to 360 parts/10(6) and phosphorus content increased NaH2PO4 . 2H2O to 0.49%. For the experimental diet, an additive containing 75 parts/10(6) fluoride as (NaF) and 50 parts/10(6) magnesium (as MgO) was mixed into the above composition. Each diet was given to three experimental or three control groups for 25, 40, or 55 d. Caries involving dentin-enamel junction was significantly reduced through the F+Mg addition by 37%, 51%, and 61% on the 25th, 40th, and 55th day, respectively. Caries involving dentin was significantly reduced by 58%, 68%, and 70%, respectively. Caries arrestment was observable in both the control rats and rats fed the F rMg additive but in the latter animals the reduction meant an arrestment at a lower level than in controls. This arrestment resembles an early caries arrestment obtained recently in a clinical trial by fluoridation of dietary sugar products. The growth of the animals was only temporarily retarded by the additives.

Animals↗
PubMed1982

Differences in PH fall, phosphorus content and dissolution of enamel in layers of the oral bacterium Streptococcus mutans deposited in vitro on bovine enamel granules with and without fluoride varnish.

Bovine enamel granules were treated with fluoride varnish for 24 h. Samples of F-treated and untreated control enamel were covered with maleic-acid-NaOH buffer (pH 5.8) previously saturated with enamel salts and containing a standard amount of fresh Strep. mutans cells plus KCl and MgCl2 (6 and 1 mM, respectively). The cells were centrifuged on the enamel; sucrose was added to the test and to control systems with fluoridated and non-fluoridated enamel; distilled water was added to non-fermenting controls. After incubation at 37 degrees C for intervals up to 2 h, fluoridation of the enamel had reduced the drop in pH of Strep. mutans plaque by 0.7 pH unit and reduced the release of Ca and P from enamel. Bacterial P levels were also significantly reduced in plaque in contact with fluoridated enamel. Magnesium concentrations outside the enamel were not altered.

Animals↗
PubMed1982

Caries reduction in rats through F + Mg supplementation of dietary sucrose with observations on bone mineral density and soft and hard tissue minerals.

Two control diets with different sucrose contents (44% and 22%) were given to weanling rats for 55 d. The test diets were supplemented with an F + Mg combination, 75 parts/10(6) F as NaF + 50 parts/10(6) Mg as MgO and 38 parts/10(6) F + 25 parts/10(6) Mg, respectively, i.e. using the same supplement/sucrose ratio in each test diet. The supplementation in each test diet caused the same percentage fissure caries reduction, but the absolute mean caries scores were higher in the high-sucrose groups than in the respective low-sucrose groups. Enamel solubility was reduced by the supplementation. Despite the high fluoride supplementation, no untoward effects were recorded in growth and in aortic, heart, and renal calcium contents. Bone mineral density was reduced in the low-sucrose controls and slightly reduced in the high-sucrose F + Mg supplemented rats, as compared with the high-sucrose controls.

Animals↗
PubMed1982

Three-year report on caries prevention of using fluoride varnishes for caries risk children in a community with fluoridated water.

The benefit of semiannual application of the sodium fluoride varnish Duraphat and the silane fluoride varnish Fluor Protection was studied in 11--13-year-old children with high caries activity and life-long exposure to fluoridated drinking water (1--1.2 parts/10(6)). Annual clinical and radiographic examinations were made of 62 children in the Duraphat group and 70 children in the Fluor Protector group. Fluoride varnish was applied semiannually using the half-mouth technique. After 3 years, for the Duraphat group mean total DMFS increments on the control side were 6.2 and on the test side 4.3 (P less than 0.001); for the Fluor Protector group the DMFS increments were 4.9 and 4.4, respectively (NS). The caries reductions were 30% and 11%. Since there were no differences between initial mean DMFS scores of the groups, it is possible that the increment in the Fluor Protector control side compared to the Duraphat control side was due to fluoride ions from Fluor Protector crossing the midline and providing protection on the control side as well. Therefore, we conclude that Duraphat proved effective, but definite conclusion of the effect of Fluor Protector cannot be made. Children with the highest DMFS increment on the control side (Duraphat) gained most from the applications.

Adolescent↗
PubMed1981

A 2-year report on caries prevention by fluoride varnishes in a community with fluoridated water.

The benefit of semi-annual applications of sodium fluoride varnish (Duraphat) and silane fluoride varnish (Fluor Protector) was studied in 11-13 year-old children with life-long exposure to fluoridated drinking water (1-1.2 parts/10(6)). Annual clinical and radiographic examinations were made on 67 children in the Duraphat group and 71 children in the Fluor Protector group. Fluoride varnish was applied semi-annually using the half-mouth technique. At the end of 2 years, the mean overall DMFS-increments on the control side and test side of the Duraphat group were 5.0 and 3.8 (p less than 0.01), respectively, and of the Fluor Protector group 3.7 and 3.3 (NS). The caries reductions were 24% and 12%, respectively. Since there were no differences between initial mean DMFS scores of the groups, it was assumed that lower increments in the Fluor Protector group were due to Fluoride ions crossing the midline and providing protection on the control side as well. When increments in the Duraphat control side and the Fluor Protector test side were compared, the caries reduction of Fluor Protector was 35% (p less than 0.01). Fluoride varnishes provide additional benefit even when fluoride intake from drinking water is optimal.

Adolescent↗