Abstract: Periodontitis is a chronic inflammatory disease,and oral lichen planus（OLP）is common in oral mucosal disease.In clinic,most OLP patients have poor periodontal status,and periodontal non-surgical treatment has an effect on it.In the pathogenesis,oral lichen planus and periodontitis are both related to immunity,genetics,psychological factors,and etc.Periodontitis and oral lichen planus can both exist,even for the whole life.Actually,health maintenance on periodontal tissue is the biggest problem that every dentist must face.This review has discussed the relationship between periodontitis and oral lichen planus to lay a foundation for the further study.

Key words: periodontitis , oral lichen planus, non –surgical treatment, correlation