Oral Surgery · patient case question
What is the minimum mesiodistal space required between two adjacent natural teeth to place a single standard-diameter implant?
Patient case: Exposed Bone After an Extraction
Patient: 68-year-old male
Chief Complaint: “The bone is showing where they pulled my tooth, and it smells bad.”
Background: Metastatic prostate carcinoma with bone metastases, on monthly intravenous zoledronic acid for 3 years. Tooth #30 extracted 10 weeks ago at another office. No history of head and neck radiation. Non-smoker.
Medications: Zoledronic acid IV monthly · Leuprolide · Calcium and vitamin D
Vital Signs: BP 132/80 mmHg · HR 76 bpm · RR 16 · T 99.1°F
Findings: A 15 mm area of exposed, necrotic-appearing bone at the #30 site with purulent drainage and surrounding erythema. No extraoral fistula. Teeth #29 and #31 are present, sound, and periodontally stable. The patient asks about replacing #30 with an implant once the site heals.
Show answer and explanation
Correct answer: A. 7 mm
- A. Correct. The arithmetic is straightforward: approximately 4 mm for a standard-diameter fixture plus 1.5 mm of clearance to each adjacent root equals 7 mm. Anything narrower requires a reduced-diameter implant or orthodontic space opening.
- B. Incorrect. Five millimeters leaves less than 1 mm of clearance on each side, which risks damage to adjacent periodontal ligaments and compromises the interproximal bone that supports the papilla.
- C. Incorrect. Ten millimeters is generous and comfortable, but well above the stated minimum requirement.
- D. Incorrect. That figure is roughly the diameter of a narrow implant alone, with no allowance for clearance to either adjacent root.