A seal assembly for a fluid pressure control device includes a guide element having a sealing surface and a first guide surface. A throttling element assembly includes a throttling element positionable within a fluid flow path, the assembly defines a mating surface adapted to seal with the sealing surface, and a second guide surface sized to slidingly engage the first guide surface. A relief void is formed in at least one of the guide element and the throttling element assembly adjacent the first and second guide surfaces to receive loose solid material, to thereby prevent disruption of the seal formed between the sealing surface and the mating surface.