Effect of thermal cycling on denture base and autopolymerizing reline resins

Objective: this study evaluated the fracture toughness (ft) of denture base and autopolymerizing reline resins,with and without thermocycling (t). material and methods: specimens of each material (denture base acrylic resin - lucitone 550 - l; autopolymerizing reline resins - ufi gel hard-uh,tokuyama rebase ii-tr,new truliner-nt and kooliner-k),were produced,notched and divided into two groups (n = 10): cg (control group of autopolymerizing reline resins and l): ft tests were performed after polymerization; tg (thermocycled group): ft tests were performed after t (5°c and 55°c for 5,000 cycles). results: results (mpa.m1/2) were analyzed by two-way anova and tukey's test (p=0.05). l exhibited the highest ft mean values in both groups (cg - 2.33; tg -2.17). for the cg groups,nt showed the highest ft (1.64) among the autopolymerizing reline resins,and k the lowest (1.04). after t,when the autopolymerizing reline resins were compared,a statistically significant difference in ft was found only between the nt (1.46) and tr (1.00). conclusions: thermocycling increased the ft of k and did not influence the ft of l,uh,tr and nt.