Newly developed “Screw Bur” to efficiently carry Impression Material or Cement into the prepared Root Canal

Abstract

Impression materials or cement should be delivered smoothly into the prepared root canals. A spiral instrument, made for endodontic treatment, has been traditionally used for this purpose.
This report deals with the efficiency of this conventional instrument in comparison with the “Screw Bur” which we have developed for prosthodontic procedures. A translucent acrylic model was used so that the materials in the canal could be directly observed. The movement of the materials-polysulfide rubber and silicone rubber impression materials and zinphosphate cement-was taken on 8 mm film for analysis.
The results may be summarized as follows:
1. Impression material and cement were delivered into the canal more rapidly when the diameter of the spiral instrument was bigger.
2. It took longer than expected to fill the canal with materials using the conventional instrument. It was too thin for prosthodontic use.
3. High velocity rotation of the instrument delivered materials more efficiently into the canal.
4. The new instrument “Screw Bur”, with a thicker diameter of 0.9mm, shortened delivery time required by the conventional instrument by 1/5 to 1/7.
5. Clinical trial use has confirmed that “Screw Bur” is effective, safe and reliable for taking impressions and when setting post crowns or cast cores onto teeth.