Hints & Tips

• Is EndoRez re-treatable?
  

  EndoRez is re-treatable. It sets harder than ZOE - more like a hard ZOE (e.g., ZOE B&T) - but not as hard as other resin fillers or restoratives. Begin by making a channel with gates-glidden drills following the gutta percha. Remove the remaining EndoRez with files. There is no chemical solvent for EndoRez.

• Can EndoRez be used by itself? With other obturating techniques?
  

  EndoRez is FDA accepted as a filler as well as a sealer. So, while it can be used alone, we recommend using at least a single cone. This gives an apical plug as well as a guide for post preparation. It may also be used with other filling techniques as a sealer in place of whatever sealer you are currently using. Its hydrophilic nature, biocompatibility, radiopacity, and superior flow characteristics will only enhance the seal of any system it is used with.

• What if EndoRez is expressed out a portal of exit (“puff” out of apex or accessory canal)?
  

  EndoRez is biocompatible, so it will not cause the irritation associated with nonbiocompatible materials. As with most sealers, it will eventually resorb. Its radiopacity makes it easier to “track” until it resorbs.

• Can a tetrachloroethylene softening solution solution be used to remove residual EndoRez?
  

  No, softening solutions will not dissolve EndoRez.

• How do I perform a post prep on the same visit when the canal is obturated with EndoRez?
  

  EndoRez takes 30–45 minutes to set up in the mouth and up to an hour to set hard. It does, however, have high oxygen inhibition. This means that it will set more slowly when exposed to air.

  In order to do a post prep the same visit, apply DeOx to the exposed EndoRez, remove the rubber dam, and have the patient bite on a cotton roll. Check the fill every 15 minutes with an explorer. When the material tests hard, the post prep may proceed.

  Begin the post channel with gates-glidden drills, using the single gutta percha as a guide. Use post drills to enlarge the post prep as usual.

• The instructions describe the use of EndoRez in cases with normal apical anatomy. Can EndoRez be used in teeth with funnel shaped or open apices? If it is possible, what are the necessary modifications to the technique?
  

  Should you encounter a large open apex, EndoREZ can be used for obturation in the following manner: Fit a cone of gutta percha into the canal for tug back, then apply a small amount of EndoRez to the apical portion of the canal. Insert the gutta percha. Now mix the EndoRez and deliver it into the canal through a NaviTip itp that is slipped alongside the gutta percha in the canal. Fill the canal as usual from the bottom up to avoid entrapment of air.

• EndoRez sets moderately hard inside the canal. Is there any solvent that can soften the set resin in the canal?
  

  EndoRez is easily removed using a gates-glidden drill or ProTaper endo removal files to gain access, followed by regular files. There are no solvents to dissolve it should a re-treatment be necessary.

• How do the sealing ability and shrinkage rate of EndoRez compare to those of gutta percha?
  

  EndoRez performs favorably. If using hot gutta percha, it is important to remember that gutta percha shrinks about 6-7% as it cools. Even with cold gutta percha and “lateral condensation,” there are numerous gaps, since it has historically been used with hydrophobic sealing materials.

  To reduce or prevent gaps in the middle third with wide canal spaces, we recommend inserting additional gutta percha but not to condense laterally.

• If resins shrink upon polymerisation, how can a resin-based obturation material seal effectively?
  

  Remember that all resin materials should not be lumped together into one category. Why? All resin-based sealers prior to EndoRez were/are hydrophobic. The hydrophilic property of EndoRez contributes a very important difference. A number of studies now show good sealing with EndoRez, and even 1200µm into dentinal tubules.

  When using EndoRez, researchers have seen unsurpassed adaptation and seal in the apical region and no shrinkage was observed there. Why? With gutta percha fit with tug-back, the dimensions of resin in the apical portion are minimal. Using the NaviTip tip to deliver EndoRez to the apex adds significantly to the predictability of this apical seal.

  Even up in the broader sections of the canal in the middle third, shrinkage gaps are minimal and less than what would be seen with lateral condensation with gutta percha. Since the tubules are filled to 1200µm, even adjacent to such a gap, bacteria in the tubules are entombed in the set resin and the apical portion is sealed.

  Having hydrophilic properties is a step forward for sealing potential for a few reasons:
  - The capability to infiltrate and seal dentin tubules that have been treated with EDTA (of File Eze or any other) and sodium hypochlorite.
  - The low contact angle at which a hydrophilic material approaches even moist dentin. This improves the capability to adapt into tiny irregularities and even into accessory canals.

• After cleaning and disinfecting, the root canal still contains a smear layer. How is it possible that the EndoRez penetrates the tubules?
  

  Cleaning with EDTA (File-Eze) followed by disinfecting with sodium hypochlorite, (ChlorCid) not only removes all the smear, but also much or all of the decalcified collagen. EDTA can be used as a conditioning agent for dentin bonding. It doesn't function in the acid sense, but chelated as a base. Sodium hypochlorite removes the decalcified collagen making an even better surface for hydrophilic resin adhesion and sealing. Such is not used for restorative dentistry because it takes many minutes to be effective and it could be damaging to surrounding soft tissues.