Australian Dental Council (ADC) Practice Test

The main reason for preferring hard alloys in dental prosthetics is their high strength and sag resistance. Hard alloys, typically composed of materials like cobalt-chrome or nickel-chrome, are specifically engineered to withstand the forces exerted during chewing and biting. This high strength ensures that dental restorations can maintain their integrity and function over time, even under the rigorous conditions of oral environments.

Additionally, sag resistance refers to the ability of the material to retain its shape and not deform under load, which is crucial for the longevity and performance of dental prosthetics. Ensuring that restorations do not warp or sag helps maintain the proper occlusion and alignment in the patient's mouth, which is vital for optimal function and comfort.

Other factors such as cost, ease of manipulation, and aesthetic results play roles in material selection as well, but they do not outweigh the necessity for strength and sag resistance when it comes to the functional performance of dental prosthetics.