Abstract: Objective: To compare the clinical effect of filling with composite resin and Lava^TM Ultimate composite resin nanoceramics inlay in repairing children first permanent molars with massive defects. Methods: The first permanent molars of 84 massive defects in 62 children treated in our hospital were randomly divided into two groups: group A was repaired with Lava^TM Ultimate composite resin nanoceramics inlay under CAD/CAM, group B was repaired with composite resin and regularly followed up. The effect of the two groups was evaluated with reference to the modified FDI standard after 6 and 12 months, respectively. Results: Six months later, there was no significant difference between two groups (P>0.05). After 12 months, there were no significant differences in surface staining, margin staining, marginal adaptation, and postoperative sensitivity between two groups (P>0.05), but the effect of group A was superior to that of group B in comparison of surface luster, fractures, retention, recurrence of caries, erosion, and exfliation (P<0.05). Conclusion: For the first permanent molars with severe defects, the long-term effect of Lava^TM Ultimate excellent-toughness porcelain is superior to resin in terms of fracture resistance, surface luster, and recurrence of caries, and is a good restorative material, which deserves to be vigorously promoted.

Key words: Lava^TM Ultimate toughness porcelain, inlay, CAD/CAM, first permanent molar, adolescent prosthetic treatment