The different effects of low-level laser therapy before and after overinstrumentation on the expression of substance P and interleukin-10.

Background: One of the causes of endodontic flare-ups is overinstrumentation during canal preparation. In general, to reduce the level of pain and swelling that is caused by endodontic flare-ups, patients it has taken analgesics and antibiotics after treatment. However, some patients have been reported to have allergic reactions to nonsteroidal anti-inflammatory drugs.