The thermomechanical properties of gutta-percha. I. The compressibility of gutta-percha​

By Schilder H, Goodman A, Aldrich W​

Date: 01/1975
Journal: Oral Surg Oral Med Oral Pathol

Purpose:

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​

Materials/Methods: 

  • 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:

  1. Molecular compression only took place in triaxial series when the stress level was ≈ 2,000 p.s.i. ​
  2. Compounded dental gutta-percha is less compressible than water. ​
  3. 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. ​
  4. No molecular “spring-back” can be expected to assist in the seal at the gutta-percha-dentin interface.​
  5. Compaction, not compression, is what obtained under clinical conditions.  ​

Clinical significance: 

Gutta-percha material undergoes compaction and not true compression during its clinical application.