This investigation evaluated the shear rebond strength of Rexillium III to enamel using various resin composite luting systems (Panavia, Imperva Dual, ABC Enhanced, C & B Met abond, Optibond, and Comspan). Cast Rexillium III cylinders (3.9% x 6.0 mm) were bonded to human molar buccal enamel surfaces (n = 8) with each cement type after etching with 37% phosphoric acid for 30 seconds. Bonded specimens were stored in distilled water for 7 days at 37 degrees C ± 2 degrees C and thermocycled (1,500 cycles) in 5 degrees C and 55 degrees C water baths (1 minute dwell time). Specimens were randomly tested in shear mode on an Instron Testing Machine at a crosshead speed of 0.5 mm per minute. Debonded specimens were then rebonded after appropriate metal conditioning and re-etching the enamel surface for 30 seconds. Analysis of variance (P 0.001) and the Ryan-Einot-Gabriel-Welsh multiple range test showed significant differences between several of the resin cements (P 0.05). Panavia exhibited significantly higher shear rebond strength than any of the other cements tested. Only Imperva Dual exhibited a significantly lower shear rebond strength compared to its initial shear bond strength.