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Biomedical subjects

L Forsten

Publications and source records attributed to L Forsten.

At least 19 recordsLinked to original sources
PubMed1995

Resin-modified glass ionomer cements: fluoride release and uptake.

The aim was to study the short- and long-term fluoride release from resin-modified glass ionomer cements (GIC). The aim was also to determine the effect of fluoride treatment of 9-month-old specimens, consistency of the mix, and pH of the environment on the fluoride release. GIC test specimens were continually exposed to running water, and the fluoride release was measured periodically by storing the specimens in 5 ml deionized water for 1 week and measuring the fluoride content of the solution. After 24 h, 1 month, 9 months, and 11 months in running water four of the six resin-modified GICs released as much as or more fluoride than the auto-curing GIC tested for comparison. Fluoride treatment after 9 months also increased the fluoride release of these four brands, as was the case with the conventional GIC. At 24 h and 1 month two of the resin-modified GICs released smaller amounts of fluoride than the other materials, and the fluoride treatment used on those had no or only a minimal effect. Thin consistency of a mix resulted in higher fluoride release for one resin-modified material than a thick mix. Low pH increased the fluoride release for all materials.

Acrylic Resins↗
PubMed1991

Short- and long-term fluoride release from glass ionomer based liners.

The aim of the study was to measure the fluoride release from glass ionomer based liners/bases after storing the specimens for 24 h and for 6 months in running water. The fluoride release was greater in the beginning than after half a year. From most liner materials the initial and the long-term release was greater than from the glass ionomer filling material studied for comparison. From two liners the release was minimal, just at the detection limit.

Acrylic Resins↗
PubMed1991

Fluoride release and uptake by glass ionomers.

The aim was to study the fluoride release 1) from 7 and 15-month-old glass ionomer specimens after treating them with fluoride; 2) from fresh compared with matured material; and 3) from specimens stored for 29 months in running water. Glass ionomer test specimens which had been in running water for first 7 then 15 months were treated with a 50 ppm fluoride solution after which the specimens were again exposed to running water for first 24 h and then 1 wk. The fluoride release was measured after each of the two periods of time. The fluoride treated specimens released more fluoride than the nontreated ones. This effect was not observed with composite resin specimens which were studied for comparison. Fluoride release from fresh glass ionomer specimens was observed to be 3-10 fold compared to specimens that had matured for 3 days. The release of fluoride from specimens that had been in running water for 29 months was measured and the results were compared with those of earlier measurements. It was found that the release reached a constant level for all tested glass ionomers during the second year.

Absorption↗
PubMed1990

Glass ionomers in proximal cavities of primary molars.

Proximal cavities with or without a dovetail were prepared in primary molars of 5-7-yr-old children. The cavities were filled with either a traditional glass ionomer (Ketac-Fil) or a cermet (Ketac-Silver). A total number of 199 treated teeth were available for evaluation 5-14 months after placement of the fillings. The percentage of success was 84% for Ketac-Fil and 77% for Ketac-Silver. There was no clear difference in rate success between the two different types of cavities.

Cermet Cements↗
PubMed1990

Short- and long-term fluoride release from glass ionomers and other fluoride-containing filling materials in vitro.

Test specimens of seven different glass ionomer filling materials and one fissure sealant were exposed to running water for 2 yr. One amalgam and one composite, both containing fluoride, were included for comparison. The fluoride release from the specimens was measured periodically after storing the specimens for 24 h or 1 wk in a small amount of water. The fluoride release from the glass ionomers decreased with time and a constant level was reached for most products during the 2-yr period. The release was increased by lowering the pH of the storage solution. The release from the glass ionomers was clearly greater than from the amalgam and the composite.

Cermet Cements↗
PubMed1984

Bond between subsequently added light activated composite resin and hardened material.

Because of the limited depth of cure, subsequent layers frequently have to be cured separately in connection with large fillings of light activated composite resins. This method is successful only provided that the different layers adhere to each other. Rectangular rodlike specimens of four light activated composites, two macro- and two microfilled brands, were made in three pieces cured separately (test specimens). The transverse strength of these specimens was compared with that of specimens made in one piece (controls). The strength of both test and control specimens of the macrofilled brands was the same even when water contamination was included when preparing the test specimens. In connection with the microfilled brands there was an indication of lower strength, at least after water contamination.

Chemical Phenomena↗
PubMed1984

The alkaline and antibacterial effect of seven Ca(OH)2 liners in vitro.

The alkaline effect of seven Ca(OH)2 liners was studied, using extractions with unbuffered 0.9% NaCl solutions and buffered bacterial growth media. The antibacterial effect was studied by cultivating Streptococcus mutans in the presence of liner specimens. All liners made the NaCl solutions strongly alkaline (pH greater than 10), although MPC and Reolite released much less Ca than did Dycal, Life, Procal, Renew, and Reocap-E. The weaker alkaline effect of MPC and Reolite was shown by the extractions with the growth media. Consequently, these two liners were not able to prevent the growth of Str. mutans. No growth was observed in the presence of the other five liners, and the media remained alkaline during the 12-h incubation period. Regrowth of the bacteria grown in the presence of these effective liners showed that only Dycal could be considered bactericidal, whereas the four other liners acted bacteriostatically.

Alkalies↗
PubMed1984

Curing depth of visible light-activated composites.

Three composites, two microfilled (Heliosit and Silux) and one macrofilled (Prisma-Fil), were exposed to visible light from three different light units. The depth of the cure was estimated by measuring the length of the test specimen after removing the uncured material. The macrofilled composite cured to a greater depth than the microfilled materials. The curing depth of Heliosit was lower, of Silux about the same, and of Prisma-Fil higher than the values of curing depth given by the manufacturers. The shade of the pastes influenced the curing depth of the macrofilled more than that of the microfilled composites. Doubling the exposure time increased the curing depth by about 1/3. Exposure through tooth substance reduced the curing depth by at least 1/3. The curing effectivity of Prisma-Lite was slightly greater than that of Heliomat and the 3M unit.

Color↗