This study evaluated the marginal sealing ability of six temporary restorative materials. Seventy-six human premolars were extracted and divided into six groups (n = 12); the remaining four teeth were used as a control group. Coronal access and biomechanical preparation were performed and the root canals were sealed. The external dental surfaces were covered and the coronal access cavities were filled with one of the six materials. At that point, the teeth were immersed in 0.2% Rhodamine B solution for 72 hours and subjected to thermal cycling. Samples were rinsed in running water and sectioned longitudinally; at that point, the images of each tooth were digitized and marginal leakage was measured using the Image Tool program. Data were subjected to statistical analysis by ANOVA and Tukey's test for comparison between experimental groups. All of the glass ionomer cements tested, particularly Maxxion R, offered satisfactory sealing ability as temporary restorative materials.