Final answer:
Guided Tissue Regeneration (GTR) is most effectively used for Grade II furcation involvements in periodontal therapy. GTR employs barrier membranes to aid in the regrowth of periodontal tissues and is less effective for advanced furcation defects such as Grade III due to their complexity.
Step-by-step explanation:
Furcation involvements are classified into three grades based on the degree of bone loss and accessibility by a periodontal probe. Grade I indicates a shallow involvements where the furcation is not clinically detectable, Grade II is where the defect is partially accessible, and Grade III is where the furcation is completely exposed.
Moderate furcation involvements (Grade II) typically benefit from GTR procedures that aim to regenerate the periodontal tissues lost due to periodontal disease. GTR involves using barrier membranes that facilitate the regrowth of bone and periodontal ligament while preventing the faster-growing epithelial cells from invading the space. This therapy allows for the potential reattachment of the periodontal tissues to the affected root surface, which could possibly convert a grade II to a grade I or result in complete resolution. The success rate decreases for Grade III furcation defects due to the advanced level of bone loss and complexity of tissue regeneration.