Given the novelty of this risk assessment tool, this study will be interested in evaluating its effectiveness through a retrospective approach. The IDRA risk will be analyzed at the time of loading the implant (s) in patients who have already placed an implant (s) during the last five years at the Department of Periodontology and Oral Surgery using the information collected from the periodontal file previously completed. Therefore, patients whose IDRA has been calculated will be called for a clinical and radiological examination to verify the development or not of peri-implantitis or the loss of the implant. In this way, this tool for predicting peri-implant disease will be evaluated to see if it is really effective.

First, the files of patients who have placed an implant(s) at the Departments of Periodontology and Oral Surgery of the Faculty of Dental Medicine of Saint Joseph University, Beirut-Lebanon over the past five years (2015, 2016, 2017, 2018 and 2019) will be collected. Subsequently, thanks to the periodontal file and to the X-rays previously taken, the eight periodontal parameters necessary for the determination of the IDRA will be recorded (history of periodontitis; percentage of bleeding on probing; the number of teeth / implants with a pocket depth ≥ 5mm; the ratio between the level of bone loss (evaluated radiographically using retro-alveolar or panoramic X-rays already present in the patient's radiological record on the DBSWIN® software) and the patient's age ( at the time of loading the implant); the susceptibility to periodontitis (diagnosis) as described by the new classification of periodontal diseases and peri-implant from the World Workshop in 2017; compliance with maintenance visits; the distance (in mm) between the limit of the prosthesis and the marginal bone level (seen on the X-ray of the infrastructure or after sealing / screwing the prosthesis); prosthetic factors (such as the precision of adaptation of the prosthesis to the implant or the excess cement) and filled in on an Excel sheet. These data will then be reported online by following this link http://www.ircohe.net/IDRA which will make it possible to calculate by itself the IDRA of each patient.

As a result, each patient will have a personalized IDRA chart and they will be either at low, medium or high risk of developing peri-implantitis.

The retrospective analysis of the files being completed, the patients will be called to come to the Department of Periodontology in order to take the necessary measures to verify the presence or absence of a possible peri-implantitis on the one hand or the loss of the implant on the other hand.

Inclusion Criteria:

1. Adults> 18 years old.
2. Patients who have placed one or more implants in the last five years at the Departments of Periodontology or Oral Surgery of the FMD and the implants have / have been loaded.
3. Patients whose periodontal file has been completed and the periodontal parameters required for IDRA reported.
4. Patients having an x-ray with the loaded implant or an x-ray during the try-in of the infrastructure.

Exclusion Criteria:

1. Patients with incomplete periodontal charts and missing parameters related to IDRA.
2. Patients not having an x-ray after loading the implant or during the try-in of the infrastructure
3. Totally edentulous patients.

All patients having placed one or more implants in the Departments of Periodontology or Oral Surgery between 01/01/2015 and 12/31/2019 and whose inclusion criteria are present to allow them to join the study .

The IPD that will be collected are confined to the Saint Joseph University's patients and their file are confidential.