Uses desensitizing toothpastes and/or topical fluoride treatments with varnishes. Even today, there is nothing wrong with trying these modalities first, since they are inexpensive and require minimal if any staff time.
If the sensitivity does not respond to these simple treatments and since the sensitive areas are usually exposed root surfaces, it makes sense to try to seal these areas using an in-office applied treatment or with potassium nitrate gel in a bleaching-like tray at home.
Blasting the sensitive area of the tooth with ozone gas has been reported to be effective by numerous users.
If the exposed root is accompanied with an actual lesion (carious or abfracted), then a definitive restoration would be indicated.
Desensitize Preparations for Indirect Restorations (at the preparation appointment)
Sealing your preparations (also known as hybridizing the dentin) at the preparation appointment prior to or immediately after taking the impression has been recommended as a way of keeping patients comfortable during the provisionalization period and possibly negates the need to administer local anesthesia at the seating appointment. Using it before the impression would alleviate the concern that the film thickness of the desensitizing layer could prevent full seating of the definitive restoration if this layer was applied after the impression. However, the film thickness of these materials is very low, minimizing this possible problem.
Nevertheless, there are no data on the effect this desensitizing layer may have on the accuracy of the impression and the ability of the lab to read your margins. In addition, if your provisional is fabricated out of a composite material, it may bond with this desensitizer, even if the preparation was lubricated liberally prior to fabricating the provisional.
To test the effect on impression materials, we took impressions of a quadrant of preparations with Aquasil and Honigum before and after applying Gluma Desensitizer to the preparations. We were unable to detect any visible differences either in the impressions themselves or on the die stone models between the control and test groups.
Effect on the bond strength of the definitive restoration is also a concern with this procedure. In other words, if you actually hybridize the dentin at the preparation appointment, will that make it more difficult to bond the definitive restoration? Our tests indicate that there is a price to pay for sealing your preparations at the preparation appointment, although the clinical significance of the slightly lower bond strength is questionable. Nevertheless, if your patients are not having sensitivity now during the provisional period, then there is probably no reason you should seal your preparations at the preparation appointment. Otherwise, the diminution in bond strength may be worth it to keep your patients comfortable.
Desensitize Preparations for Indirect Restorations (at the cementation appointment)
We have all experienced calls from patients who have sensitive teeth after their new indirect restorations have been luted. If you are bonding the restorations, proper application of an adhesive or self-etching primer should seal the tooth, minimizing or eliminating this problem. But for more conventional cementation, applying a desensitizer prior to seating the restoration should help alleviate the typical post-cementation sensitivity.
Desensitize Preparations Prior to Applying a Bonding Agent
Desensitizers are also being applied to preparations after etching, but before the bonding agent is applied. This is supposed to enhance bond strength, minimize the chances for sensitivity postoperatively, and to reduce gaps at the margins. This application can also inactivate MMPs (see Bonding Agents - Etch & Rinse). For most products, we tested the effect of this application on both bond strength and microleakage. The results are listed in the commentary for the products recommended for these functions.
With the Gluma Desensitizer patent expired on using glutaraldehyde and HEMA in this category of products, there are now a host of clones. While the chemistry is time-tested and proven, there is still concern about the mutagenic potential of using glutaraldehyde intraorally. While we do not want to be cavalier about the clinical use of potentially hazardous substances, the apparent safety of Gluma clones can be reasonably assured.
In addition, the caustic effect of HEMA on soft tissue can be problematic, since the sensitive areas on teeth are many times at the cervical. This means that it is virtually impossible to apply a desensitizer without some of it overlapping onto the gingiva. However, while the typical whitish appearance of the tissue along with the moderate soreness that can occur may raise the eyebrows in some patients, healing is usually uneventful. As long as the patient is informed before you perform, his/her reaction to this untoward effect can largely be mitigated, especially if the desensitization procedure is successful.
The significance of pH is uncertain in this group. Nevertheless, it would seem that a low pH would be counterproductive for a desensitizer.
Dedicated Product vs. Bonding Agent
Most desensitizers that are professionally applied have their origins in bonding agents. Indeed, some components of these products are straight out of the adhesive kits. So, the big question is: Do you really need a dedicated product for desensitizing dentin or will the primers of multi-component kits or the adhesive itself in a single-component version do just fine, especially if the product is a self-etching type?
The best answer is: depends on the purpose for which you are using the desensitizer. If you want a material to desensitize cervical abfractions, our experience has found a bonding agent with a primer followed by a light-cured bonding resin is the most effective technique. Or, you can use a double application of a single-component adhesive. Especially useful for this purpose is an all-in-one, self-etching product.
If you are desensitizing a preparation, there could be two good reasons to use a dedicated product: ease of use and film thickness, the latter of which needs to be minimal to allow complete seating of your restoration. However, most single-component adhesives also have minimal film thicknesses.
Sequence for Application on Abfraction Lesion
Clean the sensitive area. This is usually done with a cavity cleaner/disinfectant, mixed with pumice if the preparation is debris-laden. If you are desensitizing a non-anesthetized patient, this cleaning step may not be the most comfortable procedure.
Rinse and leave lesion with the amount of moisture specified as optimal for that specific product.
Apply the desensitizer according to the protocol specific to the product you are using.