What governing principle allows gradual distraction of bone and soft tissues in distraction protocols?

• A. Tension-Stress Effect
• B. Creep
• C. Piezoelectric Effect
• D. Wolff's Law

Answer: (A)

The governing principle is the Tension-Stress Effect. Gradual, controlled traction applies tensile forces to bone and surrounding soft tissues, stimulating cellular responses that drive new bone formation and soft-tissue lengthening. This staged, resume-and-release distraction encourages osteogenesis and tissue regeneration in the distraction gap, a concept attributed to Ilizarov. Creep describes deformation under a constant load, which isn’t the targeted biological response in distraction. The Piezoelectric Effect involves electrical changes from mechanical strain, not the regenerative process here. Wolff's Law is a general idea that bone remodels with mechanical loading, but it doesn’t specify the staged, progressive distraction mechanism used to lengthen bone and soft tissues.