Durability of Resin Bonding to Zirconia Using Products Containing 10-Methacryloyloxydecyl Dihydrogen Phosphate.

Purpose To examine the durability of composite bonding to zirconia after artificial aging using different products containing 10-methacryloyloxydecyl dihydrogen phosphate (MDP). Materials and methods Conditioning methods were: none (control [Ctr]; Clearfil SA Luting [CSL]; Panavia SA Luting Plus [PSLP]), MDP-containing zirconia primers (Z-Prime Plus [ZP]; Clearfil Ceramic Primer [CCP]), and MDP-containing universal adhesives (Single Bond Universal [SBU]; Clearfil Universal Bond [CUB]). For the Ctr, ZP, CCP, SBU, and CUB groups, the Y-TZP plates were bonded with MDP-free composite cement. For the remaining two groups, each Y-TZP plate was bonded with one of MDP-containing self-adhesive composite cements (CSL; PSLP). The specimens in each group (n = 30) were divided into two subgroups, with one subgroup of samples subjected to 24-h water storage and the other to aging through 30,000 thermocycles plus 180-day water storage. Shear bond strength (SBS) was measured. For each conditioning method, inductively coupled plasma-mass spectrometry (ICP-MS) was used to quantify the release of phosphorus, and microleakage was evaluated through a methylene-blue dyeing technique. Results The Ctr group exhibited the lowest SBS regardless of aging. Thermocycling and water storage significantly decreased the SBS in all groups, with the exception of the groups with the MDP-containing zirconia primers. Groups with MDP-containing universal adhesives and self-adhesive composite cements presented brand-dependent higher SBS, even after aging. ICP-MS detected phosphorus release from all of the MDP-containing products. Microleakage was identified at the interfaces of all bonded specimens, with the highest rate detected in the Ctr group. Conclusion MDP-containing primers, universal adhesives, and composite cements create bonds to zirconia with acceptable strength after long-term aging.