To investigate the prevalence and risk factors for peri-implant disease in partially edentulous patients rehabilitated with implants supported crown or bridge so as to provide evidence for clinical prevention and control.

The aim of the present study is to identify the prevalence of peri-implant disease in partially edentulous subjects treated with osseointegrated implants, using clinical parameters, as well as to analyse the possible disease association with demographic, behavioural, and biological risk variables.

Inclusion Criteria:

• Partially edentulous patients will implant at least one implant and will be restored with implant-supported fixed partial dentures and single crowns.

Exclusion Criteria:

• Jaw radiotherapy treatment before and after implanting. Patients who have bruxism,xerostomia or the adjacent teeth periapical periodontitis.
• Patients who suffered with oral mucosa disease,or aggressive periodontitis or jaw defect.
• Patients who suffered with mental and psychological disease will influence their oral health normal maintenance.

Partially edentulous patients implant dental implants and will be restored with implant-supported fixed partial dentures and single crowns at the Department of Prosthodontics, School of Stomatology of the Fourth Military Medical University