The effect of temperature changes on adaptation of resin fillings. II

Abstract

In earlier laboratory investigations of thermal percolation at resinous fillings the duration of the heating periods was too long to be realistic. The aim of the present work was to investigate the effect of repeated heatings of realistic duration on the formation of marginal gaps between filling and tooth during a subsequent cooling below the minimum value in the temperature cycling process. Fillings made in extracted human teeth were studied. The brands investigated were Adaptic, Blendànt, Concise, Opotow, Sevriton Simplified, and Swedon. After closure of the initial gaps by water absorption expansion the fillings were polished and subjected to thermal cycling. The specimens were cycled between either 37° and 50° C or 37° and 60° C, the duration of each immersion in the warmer bath was 2 or 5 seconds, and the number of cycles was 1, 10, 100 or 1000. The effect of the cycling was investigated by measuring the width of marginal gaps appearing at a temperature lower than 37° C. It was found that the width of the gaps was only little affected by thermal cycling between 37° and 50° C. Cycling between 37° and 60° C increased the gap widths only with Opotow, Sevriton Simplified, and Swedon. The data indicate that thermal percolation for a number of brands may be of no clinical importance.