Titanium Particles and Foreign Body Reactions in Peri-Implantitis with Implications for Comparison with Peri-Implant Mucositis: A Systematic Review and Meta-Analysis

Abstract

Background: Titanium particles and corrosion products have been proposed as contributors to peri-implant inflammation. However, detecting titanium does not establish a foreign-body reaction or distinguish peri-implantitis from peri-implant mucositis. This review examined human tissue evidence on titanium detection, particle burden, and associated inflammatory findings, prioritizing direct comparison of these two conditions.

Methods: A structured eligibility framework was applied to reports identified by web, publisher and reference-list searching on 6 October 2026. Human studies assessing titanium in peri-implant biopsies, surgical tissue or exfoliative cytology were eligible. Peri-implantitis was required; healthy implant sites, periodontitis and no-implant controls were accepted as secondary comparators. One reviewer made the original selection decisions. Targeted source verification on 7 October resolved one previously uncertain report. Findings were synthesized narratively because the direct comparison was absent and other outcomes differed in sampling, detection methods and comparator populations. Bibliographic database searching and formal risk-of-bias assessment were not completed.

Results: Of 38 identified reports, nine were retained: six comparative studies and three peri-implantitis-only studies. Twenty-three reports were excluded and six remained awaiting classification. No included study directly compared peri-implantitis with clinically defined peri-implant mucositis. Titanium was detected frequently in peri-implantitis samples, but was also found at reference implant sites. One study reported titanium concentrations of 98.7 ± 85.6 µg/g in peri-implantitis and 1.2 ± 0.9 µg/g in periodontitis controls. A paired implant-site study found no difference in particle density between diseased and reference sites. Another study detected particles in all 39 peri-implantitis specimens without histological evidence of particle-engulfing macrophages or multinucleated giant cells.

Conclusions: The identified evidence supports the presence of titanium in peri-implant tissues but does not establish that titanium is a disease-specific marker or a sufficient cause of peri-implantitis. Differences from mucositis remain unresolved. Incomplete searching, outstanding eligibility decisions and heterogeneous measurements limit the conclusions and preclude a defensible pooled estimate.