RESUMEN
Introduction: The aim of this study was to evaluate the sealing ability of a new temporary filling material X‑Temp LC (DFL, São Paulo, SP, Brazil) compared with that obtained for Coltosol (Vigodent, Rio de Janeiro, RJ, Brazil) and Vitro Fill (DFL, Rio de Janeiro, RJ, Brazil), using a dye penetration test. Methods: Standard endodontic access cavities were prepared in 75 human premolars. The teeth were divided into five groups (n = 15 for each group), including a positive (no sealing of access cavity) and a negative control (Filtek Z350 XT, 3M, São Paulo, SP, Brazil). In the experimental groups, the access cavities were sealed with one of the three tested materials. After that, the teeth were immersed in 10% Indian ink for 14 days. The teeth were then rinsed, dried, sectioned in bucco‑lingual direction and evaluated under a stereomicroscope using scores for dye penetration. Data were analyzed using Kruskall‑Wallis and Student‑Newman‑Keuls tests (α =0.05). Results: Positive control sections exhibited complete dye penetration and negative control had no specimen showing marginal leakage. X‑Temp LC and Coltosol showed similar results, with no statistical difference between them. Vitro Fill exhibited the highest dye penetration among the experimental groups. Conclusion: The results of this in vitro study suggest that all temporary restorative materials exhibit some degree of marginal leakage. X‑Temp LC and Coltosol, however seal better than Vitro Fill glass ionomer cement.