Fracture Toughness
A material property indicating a dental material's resistance to crack propagation, expressed as the critical stress intensity factor (K₁c).
Full Definition
Fracture toughness is the ability of a material containing a crack or flaw to resist further fracture under mechanical loading. In dental materials science, it is especially relevant for brittle restorative materials such as ceramics and glass-ceramics. It is reported in MPa·m¹/² and is a key parameter distinguishing materials intended for high-stress posterior restorations from those suited to anterior aesthetics. Editors should be aware that fracture toughness is a distinct property from both flexural strength and elastic modulus, even though all three appear in the same materials characterisation tables. The term is sometimes loosely used in clinical literature to mean simply 'resistance to breakage,' which editors should flag.
Usage
Usage note: Distinguish carefully from 'flexural strength' (MPa) and 'elastic modulus' (GPa); all three are distinct properties with different units.
In Context
- "The newly formulated glass-ceramic exhibited a fracture toughness of 2.5 MPa·m¹/², superior to conventional feldspathic porcelain." — Journal article abstract
- "Reviewers flagged the author's use of 'fracture toughness' where 'flexural strength' was the parameter actually tested." — Peer-review editorial note