Compressive Strength
The maximum stress a dental material can sustain under axial compressive loading before fracture, reported in megapascals (MPa), used to characterise luting cements and restorative materials.
Full Definition
Compressive strength is determined by loading a standardised cylindrical or prismatic specimen along its long axis to failure and dividing the maximum load by the original cross-sectional area. In dental materials testing, it is particularly informative for brittle materials such as cements, ceramics, and amalgam, where compressive loading predominates in vivo. Editors should note that compressive strength does not predict tensile or flexural behaviour and should not be conflated with either. Values are always expressed in megapascals (MPa); use of kPa or N/mm² requires editorial flagging. ISO 9917-1 (water-based cements) and ISO 4049 (polymer-based restorative materials) specify standardised test geometries and loading rates.
Usage
Usage note: Always report in MPa. Flag any manuscripts expressing compressive strength in non-SI or non-standard units. Do not conflate with hardness, which measures surface resistance rather than bulk failure load.
In Context
- "The zinc phosphate cement demonstrated a compressive strength of 104 MPa, exceeding the ISO 9917-1 minimum of 70 MPa." — ISO compliance test report
- "Reporting compressive strength in kN instead of MPa is a unit error requiring correction before publication." — Manuscript review checklist