Despite the bright and sunny conditions, Trent Bridge once again proved a bowlers' paradise and after Saggers had both openers caught at slip Nottinghamshire were always struggling to post a big total.
Samit Patel dug in with Wagh and Voges to give the home innings an air of respectability, but with all 10 batsmen out caught, a number will be unhappy with loose shots.
Sidebottom had seen at close quarters how much the ball was moving through the air and made the point with the first ball of the Kent innings, with a prodigious inswinger piercing Joe Denly's defences.
Charlie Shreck got in on the act to dismiss Martin van Jaarsveld leg-before in the next over, before Sidebottom took two more late in the day to force Kent onto the back foot.