On

IDS ,, Why  When  How 

 

Immediate dentin sealing is an approach to seal dentin for indirect restorations. This technique has become very famous that Pascal Magne poked , 2005 . But if you go to the literature 📚 , you’ll find the same technique named Dual bonding technique and sometimes Resin coating technique. There are three kinds of descriptions but their intention is the same, to protect dentin when we have dentin exposure.

👉🏻 For instanceduring veneer preparation, despite a major effort to confine the preparation to the enamel, some situations such as prominent or malaligned teeth may still involve deeper preparations reaching dentin. Whenever a substantial amount of dentin has been exposed by the preparation, local application of a dentin bonding agent is recommended. 

When the preparation is finished, the surface of the tooth is carefully examined in order to find the exposed dentin areas. Under normal circumstances they will usually appear on the gingival third of the tooth. However in cases of facially protruded tooth, the dentin can even be exposed on the incisal area, due to the aggressive nature of the teeth preparation.

A clinical advantage is that this precautionary measure seals and protect the pulp-dentin complex to prevent post-operative sensitivity and bacterial invasion of the exposed dentin, protection for the period between preparation and final cementation is important. It is only possible to partially seal the surface with the temporary materials (resin composite or acrylic resin) that are presently available. The use of a filled adhesive resin after acid-etching might facilitate this procedure.


Why 

This precaution not only enhances bonding and protection of the pulp-dentin complex but also prevents tooth sensitivity to keep people comfortable during the provisional phase. The frequent problem of bacterial leakage and dentin sensitivity experienced during the temporary phase, can be avoided through the use of a bonding agent. In this situation, various contaminants can alter further adhesion to dentin. Such a situation must be anticipated and solved at the time of tooth preparation because of all aforementioned problems can be prevented by the immediate application and curing of the dentin adhesive, prior to taking the final impression.
Application of this technique has been found to improve the bond strength. The recovery of crown stiffness has improved due to the more efficient bonding to dentin techniques.


When 

Because the dentin bonding agent appears to have a superior potential for adhesion when applied to freshly cut dentin, it is recommended that right after the completion of the tooth preparation, the bonding agent should be applied immediately on the freshly prepared dentin, before the final impression is taken.


How 

 Etching

After the dentin is etched for 15 seconds, a primer, which is a hydrophilic reactive monomer in an organic solvent, can be more effectively used to prime the exposed dentin. If the exposed dentin surface area is adequately retreated at the appointment prior to the actual cementation, then the primers or desensitizers that are used after the preparation do not seem to deteriorate the adhesion to the dentin.
In clinical practice, the most important factor with today's etching agents is that the dentist should not exceed the recommended time of application that is usually less than 15 seconds. Longer applications will cause the collagen to collapse and negatively affect the bonding.
If etching is properly done, the smear layer should be removed to permit bonding to the dentin matrix. It will also cause the demineralization of the matrix dentin, uncovering both the intertubular and peritubular dentin, to permit resin infiltration. It will also clean the dentinal surface free of any biofilms.

 Primer and Adhesive Application

Then the etchant is washed thoroughly, but the surface is not dried. It should only be blot-dried with the help of a cotton pellet/spong. The dentin itself has a wet character, which does not necessarily interfere with proper bonding. There should be no misunderstanding about the term wetness, as it is not a technique that allows saliva, blood or gingival fluid to contaminate the etched dentin as they contain proteins that coat the surface of the conditioned dentin and the spaces between the collagen fibers through which the resin must diffuse.
While the dentin is reasonably wet, the primer should be applied and left there for a minimum of 30 seconds. It can then be gently air-dried from a distance. At the end of this stage a shiny, stable surface should be visible.
Now the adhesive can be applied over the primer. The resin tags can penetrate into the intertubular dentin. This micromechanical bond can be better achieved if the bonding agent is cured directly after application.
Additional curing of the dentin bonding agent through a layer of glycerin jelly is recommended after the initial curing to remove the oxygen inhibiting layer and prevent interaction of the dentin adhesive with the impression material (especially polyethers) .

As the dentin is hybridized at the preparation appointment, it is fully protected. To prevent the provisional from totally bonding to, or from damaging the area, the hybridized area must be scrubbed with Vaseline after taking the impression and prior to provisional cementation.

 Cervical Marginal Check

However, the existence of this 80-micron thick adhesive may stay on the gingival margin. Therefore, the last thing to do in the tooth preparation is to delicately go over the gingival margin with an ultra fine, round-ended fissure bur, to create a clear fine margin for the impression.
When gingival margins are in dentin, a marked chamfer is recommended to provide adequate margin definition and enough space for the adhesive and overlying restoration. Magnification helps to accurately place the adhesive and remove excess resin from the margin. 

At the time of final bonding of the restoration, the surface of the adhesive must be meticulously cleansed with pumice. Further adhesion of the luting agent to the pre-existing adhesive layer must be promoted by surface roughening with a bur or microsandblasting plus drying just before luting.


👉🏻 Another instance, after crown preparation, to avoid acid etching is very recommended and the versatility of adhesive systems made it possible.

Let’s see the difference, the effect of SE primer “ two bottles “ without acid etching is more conservative. When we are close to the pulp it is recommended to avoid acid-etching technique.
  1. Clean with pumice mixed with chlorhexidine 2% .
  2. Avoid saliva contamination .
  3. Avoid acid etching .
  4. Dry dentin “ avoid overdrying “.
  5. Apply primer for 20 - 30 seconds .
  6. Do not wash .
  7. Gentle air jets for 30 seconds to evaporate the solvent .
  8. Apply bond " self-etch adhesive with two steps ".
  9. Light cure for 10 seconds each surface .
  10. Apply water based glycerin jelly .
  11. Light cure for 10 seconds each surface .
  12. Wash the glycerin jelly .
  13. Finish the preparation (only the margin).
  14. Put the retraction cord .
  15. Clean the surface with a cotton pellet & alcohol .
  16. Take the impression .
  17. Temporaries cemented with free-eugenol material .
Stay tuned for the next posts ,,
Regards ..