Peri-implantitis Risk Assessment (PiRA) Part 1: Umbrella Review of a Multifactorial Disease with Many Risk Factors

To identify relevant preoperative risk factors for peri-implantitis and provide an overview of their relative impact to reduce the incidence of the disease, which may be helpful in convincing patients to change their lifestyle-thereby reducing risk factors-or to forgo implant therapy in high-risk conditions.

An umbrella review was performed to identify patient-related risk factors and their relative impact (odds ratio/relative risk). Potential treatment-related confounders for the development of peri-implantitis were also searched for.

Ten relevant patient-related risk factors for peri-implantitis were identified. While some of them are modifiable (smoking, bleeding on probing, plaque control, number of sites with PPD ≥ 5 mm, recall frequency, and occlusal overload), others are not (history of periodontitis, implant location, number of teeth lost, and systemic diseases). The relative impact of these factors differed largely between systematic reviews, most of which unfortunately limited their analysis to one or only a few factors. Without taking other factors into consideration, these studies have a risk of result misinterpretation or overrating the results. Moreover, patients' susceptibility might change due to a number of confounders (iatrogenic factors, surgical protocol, implant and implant site characteristics, etc), and these factors should also be considered.

The number of risk factors and potential confounders underlie the complexity and multifactorial etiology of peri-implantitis.