One operator repaired defective dimethacrylate-based resin restorations that were randomly assigned to one of two treatment groups : control ( n = 50 ) , repaired with Adper SE Plus and Filtek P60 Posterior Restorative ( 3M ESPE ) ; or test ( n = 50 ) , repaired with P90 System Adhesive Self-Etch Primer and Bond and Filtek P90 Low Shrink Posterior Restorative ( 3M ESPE ) .