Dimensional stability of thermosensitive gutta-percha.

The expansion and shrinkage of four commercial brands of endodontic thermosensitive gutta-percha were evaluated. A modified volume dilatometry technique was used; the dilatometric system (DS) consisted of Pyrex glass capillary tubes and a specimen chamber. Each sample was weighed to 10(-4) mg, placed in the specimen chamber, and subjected to vacuum for 45 min to eliminate moisture or gases.