Effect of Primers on Bonding of Resin Cements to Ceramics

Objectives:  

One of the major concerns with ceramic restorations is their ability to be bonded (Dent Mater 2010; 26: 608-615).  The purpose of this study was to evaluate the effect of ceramic primers (CP) on the bond strength to ceramics (IPS e.max Press, Ivoclar (EM)), cemented with six self-adhesive resin cements (SAC) (SpeedCEM, Ivoclar (SC); RelyX Unicem 2 Automix & Clicker, 3M ESPE (UA & UC); GAM-200, GC (GM); BeautiCem SA, Shofu (BC); Clearfil SA Cement, Kuraray (SA)) and one adhesive resin-cement (AC) (Multilink Automix, Ivoclar (MA)).

Methods:  

The surfaces of EM were pretreated with IPS Ceramic Etching Gel (20 s, Ivoclar) and either pretreated by the manufacturer’s recommended CP, or not pretreated (Non).  Stainless steel rods, approximately 3.5 mm diameter & 2 mm height, were prepared and inserted into a Teflon mold, 3.6 mm diameter and 2.0 mm height, for cementation to EM with the seven resin-cement groups.  Shear bond strength (SBS) between rods and EM were measured after 24 h storage in water (37 ^oC).  Statistical analyses were performed by t-Test (Non vs. CP, p<0.05, S: Significantly different, NS: Not significantly different) and two-way ANOVA and Tukey test (between 7 groups, p>0.05, Means with the same letter were not significantly different).

Results:  

Summary: (SBS, Mean (S.D.), MPa, n=10)

         SC                UA                UC                GM                BC                SA                 MA

Non  27.0 (4.5)a   19.9 (3.6)b   24.6 (3.9)a   29.4 (8.0)a   25.8 (5.6)a   27.8 (5.9)a   19.7 (4.8)b

         S                   S                 NS                 NS                 NS                NS                NS

CP   34.1 (2.7)c   24.8 (5.4)d   25.3 (4.4)d   32.9 (6.6)c    28.5 (5.8)d    28.4 (4.6)d   19.7 (3.6)c

Conclusions:

The bond strengths of many SACs to EM pretreated by CP were not significantly greater than that of AC. Pretreatment with 5 out of 7 CPs gave no significant bond-enhancements.