I'm gonna just note the results. Server is arena.
Debuff: Item Skill: Silence lv.3
Resist: none > 12/53
Resist: Arcane Protection > 14/59
Resist: Arcane Protection + Mental Shield > 6/57
Debuff: Item Skill: Silence lv.8
Item skill: Silence affects on silenced target.
Sample 1
No resist : 15/30
Mental Shield : 12/30
Sample 2
No resist : 13/30
Mental Shield : 11/30
Debuff: Block wind walk / Block shield
Resist: Arcane Protection + Mental Shield
BWW > 28/66
BS > 8/37