Periodontics · patient case question
Guided tissue regeneration gives the most predictable result in which defect?
Patient case: Black triangles and a furcation
Patient: Female, 34 years old
Chief Complaint: “Since my braces came off there are dark gaps between my front teeth.”
Background: Fixed appliance treatment completed four months ago for anterior crowding. Non-smoker, excellent plaque control.
Findings: Triangular-shaped maxillary central incisors contacting only near the incisal edge, with an open gingival embrasure below the contact point. The distance from the contact point to the crest of interproximal bone measures 7 mm. Separately, tooth #30 has a Class II buccal furcation involvement with a narrow three-wall intrabony defect on the mesial.
Show answer and explanation
Correct answer: A. A Class II buccal furcation or a narrow two- to three-wall intrabony defect
- A. CORRECT. GTR works by placing a barrier membrane that excludes the fast-migrating gingival epithelium and connective tissue from the root surface, so that the slower periodontal ligament and bone cells can repopulate it and form a new attachment. That requires a CONTAINED, SELF-SUPPORTING SPACE with surrounding bony walls. The best-documented indications are therefore a mandibular Class II buccal furcation and a NARROW, DEEP two- or three-wall intrabony defect — the more walls and the narrower the defect angle, the better the result.
- B. Horizontal bone loss offers no contained defect at all — there are no walls to support a clot or a membrane, so there is nothing for regeneration to work with. It is managed non-surgically or with resective surgery.
- C. A Class III furcation is through-and-through. The space cannot be contained or maintained under a membrane, and regeneration there is not predictable. Class III defects are managed by root resection, hemisection, tunnel preparation or extraction.
- D. The one-wall or hemiseptal defect is the LEAST favourable of the intrabony defects for regeneration, precisely because only a single wall remains to support the blood clot and the barrier. Such defects are usually treated by osseous resection instead.
Note: Maxillary furcations respond poorly to GTR because of root proximity, trunk anatomy and access. Smoking substantially reduces regenerative outcomes and is a relative contraindication. Plaque control and resolution of inflammation must be established BEFORE any regenerative surgery, and the defect must be diagnosed by careful probing and, ideally, bone sounding rather than radiographs alone.