Materials Application Guide:
Bonding Danville's Snowpost
By Dr. Jeffrey C. Hoos, DMD, FAGDRaymond L. Bertolotti, DDS, PhD
As appeared in Dental Equipment & Materials, March 2001
Danville's Snowpost is an esthetic, radiopaque, flexible composite post reinforced with silicium fibers, enriched with zirconia. Its silanated surface is ready for direct bonding with composites. There are no mechanical knurls or other unnecessary stress risers in the post. With a bending E- modulus about twice that of dentin but much less than metal, the Snowpost has excellent stress dissipating qualities. Its low axial E-modulus follows the movements of the tooth, avoiding tensions and minimizing the risk of root fracture. At the same time, the tapered Snowpost stiffens the coronal portion of a composite post and core buildup, minimizing the possibility of a crown becoming loosened around the margins.
There are many considerations for post bonding:
Step 1. A post is selected according to the size of the dedicated reamer used (figure 1). The dedicated reamer may be used as a "try in post" to avoid contamination of the silanated post surface during a try in (figure 2). By keeping the Snowpost clean, cleaning of the post can be avoided. Should the post become contaminated, decontamination can be done by applying phosphoric acid and then washing with water. It is not usually necessary to renew the silane.
 Figure 1 |
 Figure 2 |
Step 2. The canal is cleaned of eugenol by etching with phosphoric acid. Preferably a liquid phosphoric acid etchant is utilized since gels are not easily washed from the canal. Star Etch (Danville Materials) and Gluma Etch 35 Fluid (Heraeus Kulzer) are good examples of liquid etchants.
Step 3. After etching, washing, and drying the canal, a dual curing dentin bonding agent is used to seal and to bond composite to the etched canal. The authors prefer Clearfil Photo Bond (Kuraray America) since it is a dual curing "primer and bond". The Photo Bond is easily applied with a brush such as superfine Microbrush (Microbrush). The Photo Bond is air dried to evaporate solvents. The Photo Bond does not need to be light cured since it cures very well in the dark.
Step 4. Starfill 2B (Danville Materials) or another dual-curing or self-curing flowable composite is mixed on a pad and placed into the canal with a Needle Tube Centrix). Panavia F is another good choice of materials but beware that use of ED Primer with the Panavia F severely limits working time. Photo Bond is preferred to extend the Panavia F working time. When using Panavia F, it is preferred to coat the Snowpost with Panavia F rather than insert the Panavia in the canal.
Step 5. The Snowpost is coated with Photo Bond (figure 3) and may be shortened with a rotary diamond at this time. It is inserted into the Starfill 2B already in the canal (figure 4). When using Panavia F, the Snowpost already coated with Panavia F is inserted in the canal. The Starfill 2B (or Panavia F) at the canal opening may be light cured at this time to stabilize the coronal portion while the dual cure occurs later inside the canal.
 Figure 3 |
 Figure 4 |
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