Dental Implant Planning — ORE Part 1 MCQ

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HardProsthodonticsDental Implant PlanningORE Part 1

CBCT planning is undertaken for a delayed implant-supported single crown replacing the lower right first premolar. A 4-mm-diameter implant is planned without simultaneous ridge augmentation. If at least 1 mm of bone must remain on both the buccal and lingual aspects of the implant, what is the minimum bucco-lingual ridge width required?

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Correct answer: B — 6 mm

**A. 6 mm** is correct. The stem specifies a 4-mm implant and requires at least 1 mm of bone on both buccal and lingual surfaces. Therefore, the minimum ridge width is 4 + 1 + 1 = 6 mm. This tests whether the candidate translates the required peri-implant bone envelope into the available ridge dimension, rather than recalling an unsupported universal value. **B (4 mm)** accommodates only the implant, with no surrounding bone. **C (5 mm)** leaves only 0.5 mm per side if centrally positioned. **D (7 mm)** and **E (8 mm)** would provide more bone than the stated minimum and may be clinically advantageous in some situations, but are not the minimum requested. Ridge width remains important even where vertical bone height is adequate, because insufficient bucco-lingual bone increases the risk of dehiscence and unfavourable peri-implant bone outcomes.

Reference: Alami M, et al. Ten-Year Follow-Up of Oral Implants in Bone With Limited Bucco-Oral Dimensions: A Prospective Case Series. Journal of Clinical Periodontology, 2024. https://pubmed.ncbi.nlm.nih.gov/39322233/