PERI-EDU Professional Education
Peri-implantitis cannot be diagnosed from bleeding, probing depth or a radiograph in isolation. A defensible diagnosis combines inflammatory signs, changes in peri-implant tissue dimensions and radiographic evidence of supporting bone loss. The quality of the conclusion depends on examination technique, baseline documentation and the comparability of serial images.
Educational focus: six-site peri-implant examination, gentle probing, bleeding and suppuration, mucosal recession, baseline comparison, radiographic technique, diagnostic mimics and communication of certainty.
The three diagnostic domains
| Domain | Principal findings | Clinical contribution |
|---|---|---|
| Inflammation | Bleeding and/or suppuration after gentle probing. | Identifies an active mucosal inflammatory lesion. |
| Soft-tissue change | Increasing probing depth or apical migration of the mucosal margin. | Shows alteration in tissue dimensions when compared with baseline. |
| Hard-tissue change | Progressive marginal bone loss on comparable radiographs. | Distinguishes peri-implantitis from inflammation confined to the mucosa. |
Peri-implantitis becomes the most defensible diagnosis when these domains converge. If one domain cannot be evaluated reliably, the record should state the limitation rather than imply certainty.
A reproducible six-site examination
Clinical assessment should include six sites around each implant whenever the restoration permits access. Use a light probing force and record values by site rather than as a single implant-level number.
- Probing depth: document the depth at reproducible sites and compare it with previous measurements.
- Bleeding on probing: record its presence and distribution after gentle probing.
- Suppuration: identify the exact sites where exudate appears.
- Mucosal margin: record recession or coronal position relative to a stable restoration landmark.
- Plaque and deposits: assess the local inflammatory exposure.
- Access: document surfaces where restoration contour prevents reliable probing or cleaning.
Gentle probing is safe and necessary
Careful probing provides essential information about bleeding, pocket depth and the mucosal margin. Routine probing with light force does not produce lasting injury to peri-implant tissues. Avoiding probing simply because an implant is present can delay recognition of inflammatory and structural change.
No universal probing depth separates health from disease. Healthy implants can have relatively deep sulci because tissue thickness, implant position and prosthetic design vary. A deep measurement should therefore prompt comparison with baseline records and inflammatory findings rather than an automatic diagnosis.
Bleeding and suppuration
Bleeding on gentle probing is a sensitive sign of mucosal inflammation, but it does not establish progressive bone loss. Peri-implant mucositis can bleed extensively without peri-implantitis. Radiographic comparison prevents an inflamed site from being overclassified as destructive disease.
Suppuration increases concern for advanced inflammation and should be recorded by site. It still cannot quantify bone loss or define defect morphology. Combine it with probing, mucosal-margin measurements and radiographic findings.
Recession can conceal tissue loss
Probing depth may appear stable when the mucosal margin migrates apically. For example, a two-millimetre reduction in probing depth accompanied by two millimetres of recession does not represent stable tissue support. Record probing depth and the mucosal margin separately so their combined change remains visible.
Diagnosis with baseline records
A post-restorative clinical chart and radiograph provide the strongest diagnostic anchor. When baseline data are available, peri-implantitis is identified by inflammatory signs together with increasing probing depth or recession and bone loss beyond expected initial remodelling. Comparable technique allows progression to be demonstrated rather than inferred.
Early crestal bone adaptation after implant placement and loading is not automatically peri-implantitis. Timing, inflammatory status and further change determine whether a finding represents remodelling or pathological progression.
Diagnosis without baseline records
When previous radiographs and probing measurements are unavailable, the 2018 case definition uses three current findings:
- bleeding and/or suppuration on gentle probing;
- probing depth of at least 6 mm;
- bone level at least 3 mm apical to the most coronal intra-osseous part of the implant.
This threshold-based definition supports classification in the absence of longitudinal data. It carries more uncertainty than a diagnosis based on demonstrated progression and should be documented as such.
Radiographic assessment
Standardised intraoral periapical radiographs remain the primary method for serial evaluation of marginal bone levels. Use a paralleling technique and a reproducible holder when possible. Measure from the same stable implant landmark on every image.
Projection error can mimic marginal bone-level change. Vertical or horizontal angulation differences alter the apparent relationship between implant threads, the implant shoulder and the bone crest. Before interpreting a small change as progression, check image sharpness, projection and visibility of the implant-bone interface.
Limits of two-dimensional imaging
Periapical radiographs display mesial and distal bone most clearly. Buccal and lingual defects may remain hidden by superimposition, and a normal interproximal image does not exclude circumferential bone loss. Three-dimensional imaging should be reserved for situations in which the added information can change management and radiation exposure is justified.
Defect morphology
Peri-implant bone defects often contain circumferential components and can combine intrabony and supracrestal loss. Surgical access may reveal anatomy that a two-dimensional radiograph underestimated. Morphology affects access for decontamination and the potential for regenerative treatment, although it is not required to establish the initial diagnosis.
Prosthetic access and diagnostic confidence
Bulky emergence profiles, deep restoration margins and unfavourable implant position can obstruct probe insertion. If a surface cannot be examined reliably, document the limitation. Prosthetic modification or removal may be appropriate when improved access can change diagnosis or treatment planning.
An inaccessible site should not be recorded as a negative finding. The absence of a measurement is different from a normal measurement.
Diagnostic mimics and competing explanations
| Possible explanation | Potential presentation | Verification |
|---|---|---|
| Residual cement or foreign material | Local bleeding, suppuration or focal bone loss. | Inspect restoration margins and remove the local irritant when indicated. |
| Implant or component fracture | Pain, mobility, recurrent screw problems or local radiolucency. | Assess component fit, prosthetic integrity and implant stability. |
| Technical or occlusal complication | Discomfort, loosening or fracture without the complete inflammatory pattern. | Evaluate occlusion and the restorative complex together with the tissues. |
| Implant malposition or poor contour | Restricted hygiene access, persistent plaque and unreliable probing. | Assess whether prosthetic modification can improve access. |
Biomarkers remain adjunctive
Inflammatory mediators such as interleukin-1 beta and tumour necrosis factor alpha may be elevated at diseased sites. Substantial overlap between health, mucositis and peri-implantitis limits their diagnostic discrimination. No single biomarker currently replaces clinical examination and radiographic comparison in routine care.
Communicating diagnostic certainty
- Confirmed: comparable longitudinal records demonstrate inflammation and progressive supporting bone loss.
- Probable: current findings meet the accepted threshold-based definition, but baseline records are unavailable.
- Indeterminate: inadequate imaging, restricted access or a competing explanation prevents reliable classification.
The clinical record should identify the case definition used, sites examined, image technique, relevant limitations and the next diagnostic or management step.
Key learning points
- Gentle six-site probing is safe, necessary and most informative when repeated consistently.
- Bleeding identifies inflammation, while progressive bone loss distinguishes peri-implantitis from mucositis.
- Baseline clinical measurements and a post-restorative radiograph provide the strongest diagnostic anchor.
- Two-dimensional images can underestimate circumferential, buccal and lingual defects.
- Explicit communication of diagnostic certainty improves referrals, treatment planning and follow-up.
Download the full educational material
The extended PDF provides a complete examination sequence, case definitions, radiographic interpretation principles, diagnostic limitations and a practical documentation workflow.
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Selected references
- Berglundh T, Armitage G, Araujo MG, et al. Peri-implant diseases and conditions: consensus report of workgroup 4 of the 2017 World Workshop. Journal of Clinical Periodontology. 2018;45(Suppl 20):S286-S291. doi:10.1111/jcpe.12957.
- Renvert S, Persson GR, Pirih FQ, Camargo PM. Peri-implant health, peri-implant mucositis, and peri-implantitis: case definitions and diagnostic considerations. Journal of Clinical Periodontology. 2018;45(Suppl 20):S278-S285. doi:10.1111/jcpe.12956.
- Schwarz F, Derks J, Monje A, Wang HL. Peri-implantitis. Journal of Clinical Periodontology. 2018;45(Suppl 20):S246-S266. doi:10.1111/jcpe.12954.
- Herrera D, Berglundh T, Schwarz F, et al. Prevention and treatment of peri-implant diseases: the EFP S3 level clinical practice guideline. Journal of Clinical Periodontology. 2023;50(Suppl 26):4-76. doi:10.1111/jcpe.13823.
- Monje A, et al. Diagnostic methods and parameters to monitor peri-implant conditions. Periodontology 2000. 2024. doi:10.1111/prd.12584.
- Sahrmann P, et al. Radiographic assessment of the peri-implant site. Periodontology 2000. 2024. doi:10.1111/prd.12577.
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This educational material does not replace individual clinical assessment or specialist consultation.
This work was co-funded by the European Union under grant agreement No. 2024-1-PL01-KA220-HED-000251208. Views and opinions expressed are those of the author(s) only and do not necessarily reflect those of the European Union or the Foundation for the Development of the Education System (FRSE). Neither the European Union nor FRSE can be held responsible for them.