Effect of prolonged direct and indirect peroxide bleaching on fracture toughness of human dentin.

Statement Of The Problem: The effects of prolonged exposure to peroxide bleaching agents on dentin structural integrity are uncertain.

Purpose: To evaluate the effect of in vitro prolonged tooth bleaching on the fracture toughness (K(1C)) of human dentin.

Materials And Methods: Dentin from recently extracted molar teeth was directly or indirectly treated to simulate a prolonged at-home (10% carbamide peroxide or 3% hydrogen peroxide, 6 hours/day, 5 days/week for 8 weeks) or in-office (30% hydrogen peroxide, 1 hour/week for 8 weeks) bleaching regimen (N=8/group).