Implants · patient case question
Which bacteria predominate in peri-implantitis?
Patient case: Implant treatment planning
Patient: Male, 38 years old
Chief complaint: “I'm missing some teeth and I'd like replacements.”
History: Ectodermal dysplasia. Skeletal growth complete. Otherwise healthy, non-smoker.
Findings: Hypodontia with several edentulous spaces. Adequate bone volume on CBCT. A single edentulous space between two natural teeth measures 7 mm mesiodistally. Peri-implant inflammation is present around an implant placed elsewhere three years ago.
Show answer and explanation
Correct answer: B. Gram-negative anaerobes
- A. Gram-positive facultative rods such as Actinomyces species belong to early plaque maturation and root-surface caries.
- B. CORRECT. The peri-implantitis microbiota closely resembles that of chronic periodontitis — predominantly GRAM-NEGATIVE ANAEROBES including Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Prevotella intermedia and Fusobacterium species. This is the practical basis for treating implant patients' remaining natural teeth first: untreated periodontal pockets act as a reservoir that seeds the implant surface.
- C. Gram-positive aerobic cocci such as Streptococcus sanguinis dominate EARLY supragingival plaque and healthy peri-implant sulci. They are where colonisation starts, not where disease ends up.
- D. Obligate aerobes cannot survive in the anaerobic environment of a deep peri-implant pocket.
Note: The key management distinction: peri-implant MUCOSITIS is inflammation confined to soft tissue and is REVERSIBLE with debridement and hygiene. Peri-implantITIS involves progressive BONE loss and is not reliably reversible — which makes early detection and regular probing essential.