At 20 years implants hold up like natural teeth — but only with maintenance

How do implants behave over the very long term in patients who have had periodontitis? This observational cohort study followed 167 systemically healthy, non-smoking patients with treated periodontitis and 419 implants, comparing each implant with its contra-lateral natural tooth at 5, 10, 15 and 20 years under regular supportive periodontal care (SPC). Clinical attachment level (CAL), probing pocket depth (PPD), gingival margin and bleeding on probing (BOP) were recorded at every recall.

The headline finding is reassuring: over twenty years, implants and natural teeth showed comparable clinical stability and survival. Mean CAL rose significantly at both, roughly doubling every five years, reaching about 4.5 mm of loss at implants and 4.4 mm at teeth by 20 years, with between-group differences largely non-significant beyond 5 years. Implants, however, showed greater PPD increases than teeth at 10 and 15 years, a sign that pockets tend to deepen somewhat faster around implants. Implant survival was 100% and only three contra-lateral teeth were lost over 20 years.

Two caveats temper the optimism. First, attachment loss progressed at both teeth and implants despite maintenance: SPC limits but does not abolish the slow drift. Second, no association emerged between SPC frequency and change in CAL or PPD, a result to read in light of the selected, compliant population rather than as licence to relax recalls.

In practice, in well-selected, maintained periodontitis patients the implant is a durable replacement, with survival equal to that of the natural dentition at 20 years. The deeper lesson is vigilance: long survival does not mean static tissues, and peri-implant PPD in particular deserves continuous monitoring.