Crown-down tip design and shaping

By Del Bello TP, Wang N, Roane JB

Date: 01/2003
Journal: JOE


Purpose: To examine the effect of file tip designs on the prevalence of instrument damage, breakage, extend of transportation, and ledge formation during Roane’s crown down method.

 N= 90. curved canals were divided by degree of curvature into three equal groups of 30


  • Studied shaping effects of 3 types of SS files that differ in tip design in curved canals in acrylic blocks. The sample canals divided by curvature (by schneider) into 3 equal groups. 3 types of file tips: flex-r (biconical) morflex (conical) flex-o (pyrimidal)
  • Instrument sizes 60 to 25 were used(all canals shaped to size 60 file) with water irrigation. The apical 7 mm of the canal spaces were prepared using one of the three different files
  • Pre and post op canals analyzed digitally.

Most highlighted Results:

Significant results between files (P< .05). Biconical tips showed least transportation and no ledges but more damaged than conical-tipped. Pyramidal tips showed most transportation, ledges, damaged files and separation.

Participants reported less difficulty shaping with biconical tips and greatest difficulty with pyramidal tips (more pressure).

Clinical Significance:

Tip design has a strong influence on the final canal shape, biconical tipped files maintain original canal curvature best. Incremental shaping of the crown-down technique depends on the performance of an instrument’s.