Implants · patient case question
What is the minimum mesiodistal space required to place a single implant between two natural teeth?
Patient case: Implants, Peri-implantitis, and a Regeneration Question
Patient: 59-year-old male
Chief Complaint: Review of two implants placed four years ago, and assessment of a defect on tooth #6.
Background: Former smoker. History of treated periodontitis. Irregular maintenance attendance.
Medications: None
Vital Signs: BP 130/82 mmHg · HR 74 bpm · RR 16 · T 98.4°F
Findings: Implant at site #19: 6 mm probing depth with bleeding and suppuration, 2 mm of radiographic crestal bone loss. Tooth #6 has a NARROW three-walled intrabony defect on its MESIAL surface, 6 mm deep, with the tooth firm and vital. Posterior mandibular ridge is being assessed for a further implant.
Show answer and explanation
Correct answer: D. 7 mm
- A. 10 mm is generous and comfortable but is not the MINIMUM.
- B. 5 mm would leave only 0.5 mm on each side of a 4 mm implant — insufficient bone, with predictable crestal resorption and papilla loss.
- C. 4 mm is the implant diameter alone with no clearance at all.
- D. CORRECT. Approximately 7 mm. The arithmetic is simple and worth being able to reconstruct: a standard 4 mm diameter implant, plus a minimum of 1.5 mm of bone to the root of each adjacent tooth, gives 4 + 1.5 + 1.5 = 7 mm. That 1.5 mm on each side is what preserves the crestal bone and, with it, the interdental papilla.
Note: Two other dimensions that come up alongside this: the distance from the implant platform to the contact point should be 5 mm or less for reliable papilla fill, and adjacent implants need 3 mm between them (not 1.5) because two implants together produce more crestal resorption than an implant beside a tooth.