Three-body and toothbrush abrasion of novel self-adhesive resin cements

Objectives: To evaluate the wear resistance of novel self-adhesive resin cements in the luting gap using an in vitro three-body wear (ACTA) and a toothbrush abrasion machine and to correlate the two test methods.

Methods: Luting gaps of 300µm width and 2mm depth were prepared on either glassceramic flat substrates (n=12) or on ACTA abrasion wheels (n=9) using a diamond saw. The gaps were filled with four dual-cure self-adhesive and one light-cure resin cements according to manufacturer recommendations, surface grinded and stored for 14d in dist. water. Toothbrush abrasion was conducted in a toothbrush simulator (Willitec, Germany; p=2N) using a commercial toothpaste slurry (Elmex, Gaba, Germany, RDA=70). The resulting gap depths were measured after 20,000 cycles. Three-body wear testing was performed according to the ACTA principles (Willytec, Germany; p=15N) in a millet seed slurry. The wear trace after 400,000 cycles was measured in comparison to the non-worn surface. The luting gap depths and mean wear depths were measured with a confocal laser scanning microscope (CLSM, Leica, Germany). The data were analyzed using a two-way ANOVA and mod LSD test (p<.05).

Results: Same superscripts indicate homogenous subsets [Mean (SD)].

	Toothbrush abrasion depth [µm]	Three-body wear depth [µm]
Exp (Voco)	4.93 (1.36)a	21.00 (2.71)b,c
Maxcem (Kerr)	11.84 (3.51)	24.16 (3.87)
Multilink Sprint (Ivoclar)	6.47 (1.69)a	31.73 (8.84)
RelyX Unicem (3MESPE)	5.77 (1.46)a	27.74 (3.40)
Variolink II Base (Ivoclar)	19.29 (4.06)b	18.28 (2.59)c

Conclusions: Best toothbrush abrasion resistance showed Exp, Multilink Sprint and RelyX Unicem. Lowest three-body wear rates showed Exp and Variolink II Base. There is no correlation between the two test methods (r²=0.385).

This study was supported by Voco