The only BIG BUT we accept has 2 T's

There are never any "but's" that work for me. 
And yes, I mean the but with one "T" ! 

But he's young,
But he's only just started working,
But he has no bit in his mouth,
But he eats well,
But 2 years ago there was nothing to be seen,
But he's super easy to ride,
But I didn't know,
But my godmother's neighbour who is in charge of the horse feeding at the barn told my friend it's useless,
But unicorns didn't get this done,
But in nature horses don't get this done either,
But my coach's son's girlfriend, who teaches looked and said it wasn't worth doing it,
But, but... BUT... nothing at all.

There's no but, there are only excuses. Excuses that lead to many problems and pain.

So yes, let me put it clearly. Even if you didn't know ... he can be in pain when you don't had dental work done. 

In pain not just when you're riding. 
When he eats, when he drinks, when he works, and all the rest of the time actually, he just hurts.

Don't look for excuses, look for a vetrinarian with specialisation in dental work, your horse dentist and have your horse checked once a year at least, just to be sure ! 
Check your horses mouth (ponies, donkeys, llamas, unicorns for the lucky ones), this is in one word: important.