A methodologic study of the effect of dental materials on growth and adhesion of animal cells in vitro

Abstract

– An in vitro method was used to investigate the ability of animal cells to (a) grow in the proximity of various dental materials, (b) adhere to and grow on the surface of the same materials during long‐term contact. Disks (30 × 1 mm), made from the different materials, were placed in the center of plastic Petri dishes and incubated with human epithelial cells (NCTC 2544) and mouse fibroblasts (L 929). The growth around and on the surface of the disks was followed by measuring the amount of deoxyribonucleic acid (DNA) and/or cell number. The cultures were stained with crystal violet to visualize the distribution of the cells. In the presence of gold alloy, growth was similar to that obtained in control cultures, whereas the other materials tested showed various degrees of a toxic effect. With the two heat‐cured acrylics tested, a transient toxic effect was observed on the surface of the disks. In the presence of silicate cement, various degrees of growth inhibition were observed, both on the surface of and around the disks. A toxic effect of silver amalgam was evident on the surface of and in the close proximity of the disks, whereas Addent 12® and copper amalgam appeared to have a general toxic effect. The present method might thus be of value in the evaluation of the tissue compatibility of biomaterials.

pH and the cytotoxicity of fluoride in an animal cell culture system

“…Combinations of fluoride and pH within the range found in silicate cement cultures (15 to 24 |j,g fluoride/ml and pH from 7.0 to 6.4, HELGELAND & LEIRSKAR 1973) caused a rapid cytotoxic effect. This suggests that fluoride and a low pH may play a decisive role in the observed cytotoxicity of this material (HELGELAND & LEIRSKAR 1972). When pH of the medium was lowered from 7.4 to 6.7, the intracellular-to-extracellular fluoride ratio increased from 0.4 to 0.8, i.e.…”

“…Glucose and lactate contents were measured enzymatically with reagents from Boehringer Mannheim, GmbH, Mannheim, West Germany. Details of the analytical procedures have been described previously (HELGELAND & LEIRSKAR 1972, 1973.…”

“…Upon lowering the pH of the incubation medium from 7.4 to 6.7 a twofold increase in the intracellular concentration of fluoride was found. Previously, we have described the growth inhibitory effect of silicate cement in a cell culture system (HELGELAND & LEIRSKAR 1972), During incubation, zinc, silicon, fluoride and phosphate were released from the silicate cement disks (HELGELAND & LEIRSKAR 1973), pH decreased and magnesium and calcium were adsorbed from the medium.In the present experiments the importance of acidification and the release of fluoride for the observed cytotoxicity of silicate cement was studied. The effects of fluoride and pH on glucose metabolism, growth and morphology of human epithelial cells in culture were tested separately and in combination.…”

“…Upon lowering the pH of the incubation medium from 7.4 to 6.7 a twofold increase in the intracellular concentration of fluoride was found. Previously, we have described the growth inhibitory effect of silicate cement in a cell culture system (HELGELAND & LEIRSKAR 1972), During incubation, zinc, silicon, fluoride and phosphate were released from the silicate cement disks (HELGELAND & LEIRSKAR 1973), pH decreased and magnesium and calcium were adsorbed from the medium.…”

A timeline of biological assessments: Our nonspatial continuum

“…We have endeavored to present all of the available literature to develop our biological testing timeline of restorative materials-the beginnings are traced from Dr. Kinyoun of the Marine hospital of Ellis Island of 1779. In vivo tests were first reported by Manley in 1936 [46] followed by an in vitro report of Kawahara in 1959 [37][38][39]. Since then, the scientific community has refined biological testing models to demonstrate that microleakage of microörganisms & their products through the restorative interface are of greater damage to vital pulp tissues than the pH of restorative agents [75][76][77][78][79][80][81][82].…”