Such treatment can be upsetting to a lad about ten (6)
I believe the answer is:
dental
'such treatment can be upsetting' is the definition.
I can't judge whether this defines the answer.
'lad about ten' is the wordplay.
'about' indicates an anagram.
'lad' mixed up with 'ten' makes 'DENTAL'.
'to a' acts as a link.
Can you help me to learn more?
(Other definitions for dental that I've seen before include "Pertaining to teeth" , "Concerning teeth" , "surgery" , "sort of surgeon" , "concerned with choppers" .)