Thank you for the explanations!
When you said that the problem should be "rectified", do you mean reapplying LA to the patient?

And I've one other question (that doesn't really fit in this thread though): most people believe that dentists have the highest suicide rates, would this be fact or fiction? If it does end up being true, could you please shed any light on why this may be? I thought unappreciative patients might be one reason.

One dentist I asked told me that it was merely a rumour created by "jealous" medical students (but I think it was meant to be a joke)