The lingual bar must be shaped half pear-shaped with the bulge inferiorly to provide maximum strength and rigidity while minimizing tissue contact. This design allows the bar to resist deformation under masticatory forces, ensuring durability and patient comfort. The inferior bulge keeps the bar away from the delicate lingual gingiva and floor of the mouth, reducing soft tissue irritation and potential ulceration. Additionally, the half pear shape fits the anatomical contour of the lingual sulcus, preserving tongue space and avoiding interference during function.

Reference: Prosthodontics: Principles and Management Strategies, George A. Zarb, Edition 4