Peri-implantitis is the infection-driven destruction of the bone supporting a dental implant. Prevalence estimates in the literature range from 22–65% of implant patients over 10 years. It is the single greatest threat to long-term implant survival and the most common reason experienced implantologists lose cases they placed years earlier.
Understanding the Disease
Peri-implant disease exists on a spectrum. Peri-implant mucositis — the reversible precursor — is confined to soft tissue and resolves with improved plaque control. Peri-implantitis involves progressive bone loss and requires active intervention. The transition from mucositis to peri-implantitis is a critical window for prevention.
Risk Factors
- History of periodontitis: Single strongest predictor. Patients who lost teeth to periodontal disease are at highest risk.
- Smoking: 2–4x increased risk. Nicotine impairs angiogenesis and host immune response at the implant site.
- Poorly controlled diabetes: HbA1c above 7.5% correlates with increased peri-implant bone loss.
- Excess cement: Subgingival residual cement is a major local cause. Use screw-retained restorations wherever possible.
- Implant depth: Over-buried implants create a deep peri-implant pocket difficult to instrument. Platform switch to equip crestal bone.
The CIST Protocol for Treatment
Cumulative Interceptive Supportive Therapy (CIST) stages treatment by severity:
- Stage A (mucositis): Mechanical debridement, oral hygiene instruction
- Stage B (shallow pockets, no bone loss): A + antiseptic treatment (0.2% CHX gel or irrigation)
- Stage C (bone loss present): A + B + systemic antibiotics (metronidazole + amoxicillin 7 days)
- Stage D (advanced bone loss): A + B + C + surgical intervention (resective or regenerative)
Prevention Protocol — Build This Into Your Practice
Review at 6 months post-loading, then annually. At each review: probe all implants, take periapical radiograph, compare to baseline. Any bleeding on probing = mucositis. Begin treatment immediately. Do not wait for bone loss to appear on radiograph — by then you are already at Stage C.
