cusp deflection, infraction and fracture in endodontically treated teeth filled with three temporary filling materials (in vitro)

Aim: the aim of this study was to compare cusp deflection, infraction and fracture in teeth filled with three temporary filling materials. materials & method: forty five extracted human premolar teeth were chosen. after root canal therapy and mesio-occluso-distal cavity preparation, samples were randomly divided into three groups , each contained 15 teeth and filled with three temporary filling materials: cavisol (golchai-iran), coltosol f (coltene,swiss) and coltene (ariadent,iran). teeth were kept in normal saline at room temperature and every day the intercuspal distance was measured under stereomicroscope for 20 days. infractions as well as fractures were also noted. data were analyzed in spss 17 using repeated measurement anova test to evaluate the intercuspal distance and expansion of each sample every day. results: intercuspal distance increased in all three groups but was significantly more in coltosol f group. on the days 10 and 16 two teeth filled with coltosol f had cusp fracture. conclusion: temporary filling materials have hygroscopic expansion and cause cusp deflection which may lead to cusp fracture, so it is recommended to use them in short period of time.