To determine the mechanism through which volume of gutta-percha is presumed to be reduced with pressure with uniaxial and triaxial systems of physically absolute design
- Samples of both compounded (rolled cones) and uncompounded (slabs 1/2 inch thick) gutta-percha Each were weighed to ≈8 grams, placed into the cylinder system, diameter & thickness were recorded.
- Compression tested to 20,000 pounds in triaxial state, at room temperature & 68o C.
- Uniaxial testing was performed at room temperature only.
- A Tinius-Olsen tension compression machine was used for the actual compression phase of the experiment.
Most highlighted Results:
- Molecular compression only took place in triaxial series when the stress level was ≈ 2,000 p.s.i.
- Compounded dental gutta-percha is less compressible than water.
- The reduction in apparent volume which takes place as a result of mechanical manipulation is due to consolidation and collapse of internal voids and occurs well within compaction forces.
- No molecular “spring-back” can be expected to assist in the seal at the gutta-percha-dentin interface.
- Compaction, not compression, is what obtained under clinical conditions.
Gutta-percha material undergoes compaction and not true compression during its clinical application.