Some feel a dentist is burdened (5)
I believe the answer is:
laden
'is burdened' is the definition.
(synonyms)
'some feel a dentist' is the wordplay.
'some' indicates the answer is hidden within the clue (some of the parts of the word are used).
'LADEN' is hidden in the letters of 'feel a dentist'.
(Other definitions for laden that I've seen before include "Of ship, having taken on cargo" , "Like cargo boat" , "Like many a cargo ship" , "Carrying a load" , "Filled (with)" .)