Abstract: Objective: To analyze the clinical manifestion and treatment method of one patient with severe periodontitis complicated with oral lichen planus, and to clarify the effect of combined treatment method and the importance of regular follow-up.Methods: The clinical manifestion of the patient was that the bilateral moral teeth had become looseness and the gum had bled for six months,and the patients had a history of oral lichen planus in gum for 2 years old. The probing depth(PD) of all the teeth was 5-6 mm and the attachment loss(AL)was 8-9 mm,with Ⅱ°-Ⅲ°mobility and bleeding on probing (BOP)(+).The teeth was treated with the regular basis periodontal treatment combined with gingival triamcinolone acetonide injection treatment.When the inflammation situation remained stable, the delayed implantation was performed and the crown restoration treatment was done for 26,27,36 and 37.The splinting treatment was done for 31 and 41 Ⅱ° mobile teeth. The regular follow-up periods were 1 week,2 weeks,1 month,3 months,and 6 months after treatment during periodontal maintenance.Results: After combined treatment and regular follow-up,the PD of both anterior and premolar were 4 mm,and the BOP was negative. The clinical symptom of oral lichen planus of the patient was relieved, and there were no symptoms of congestion and erosion on the gum. After the inflammation situation was controlled, the chewing function of the left molar region was restored by implantation rehabilitation. A 3-month-follow-up cycle and excellent treatment compliance were beneficial for the control of disease. The optimal follow-up period of gingival condition maintained best was once per 2 weeks.Conclusion: The combined treatment can relieve the clinical symptoms of the patient with severe periodontitis complicated with oral lichen planus. Regular follow-up and excellent treatment compliance are conducive to controlling the condition of disease.

Key words: severe periodontitis, oral lichen planus, basic periodontal treatment, treatment compliance, probing depth