George Smith arrives from fellow National League side Chesterfield, and Ntumba Massanka joins from Burnley, both on loan deals.
The Whites' manager Chris Kinnear admitted that he was looking for reinforcements after his side lost 3-0 at Leyton Orient on Monday - their fifth defeat in seven games.
A defender, Smith joined the Spireites in January from Northampton but has previously helped Barnsley to promotion to the EFL Championship.
The 22-year old left-back has National League experience having played 38 games for Gateshead.
Striker Ntumba Massanka arrives at Crabble from Premier League Burnley previously had two loan spells with Wrexham in the National League.
The 21-year-old has signed on loan until January and has previously played for Morecambe and York City.