Dental OSCE (Objective Structured Clinical Examination) Practice Exam

What condition is described as "marbled bone disease" characterized by the deposition of bone that is weak?

1. Osteopetrosis

2. Osteoporosis

3. Osteomalacia

4. Osteosarcoma

The correct answer is: Osteopetrosis

The condition known as "marbled bone disease" refers to osteopetrosis, which is characterized by an abnormal increase in bone density due to a defect in the osteoclasts, the cells responsible for bone resorption. In osteopetrosis, the excessive deposition of bone leads to a marble-like appearance on radiographs and results in bones that are not only very dense but also structurally weak and brittle. This paradox occurs because, while the bones are dense, they lack the normal remodeling processes that make them strong and functional, leading to an increased risk of fractures. The diagnostic imaging typically reveals bones that appear overly radiopaque or "marbled," which helps differentiate this condition from others that affect bone density, such as osteoporosis, which involves thinning of the bone, or osteomalacia, which is characterized by inadequate mineralization of the bone matrix despite sufficient quantities of bone matrix being present. Osteosarcoma, on the other hand, is a type of bone cancer that primarily impacts the quality of bone formation and is not characterized by the marbling associated with osteopetrosis. Thus, the description of the disease and its features firmly aligns with osteopetrosis.