The most common and most likely answer to this crossword clue is the 8 letter word DENTISTS
I've seen this crossword clue in The Guardian
D
E
N
T
I
S
T
S
More clues leading to the result DENTISTS
- They look down in the mouth when at work
- They fill much of their working days
- First to fill cavities?
- First people with drills
- They may fill craters covering island road
- These should be able to cap disastrous D in tests
- It’s about filling cavities for these doctors
- They make money from cavities?
- They prefer wide, open mouths with dimples having one small indentation in the middle
- It's wrong to be limited by impressions some may drill into you
Buddy explains!
The straight part
We know that "They fill much of their working days" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case they fill much of their working days = dentists.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does DENTISTS mean?
DENTISTS noun- A medical doctor who specializes in dentistry.