Q and A with Dr. Joe Blaes

March 8, 2010

Question: My patients seem to have a lot of post preparation (crown) sensitivity, even after permanent cementation. I've used different cements, and currently use Infinity. Occlusion doesn’t appear to be the issue. I'm aware 4% to 8% of teeth treated will have pulpal trauma. Are there any "Gems" out there to reduce sensitivity at prep time, or just before cementation? — Dr. T

Answer: Hello Dr. T. This is not a simple question because there are many factors that can cause sensitivity. I must tell you that while I have little sensitivity when cementing crowns, inlays, or veneers, there is often one with sensitivity that I didn’t expect and cannot find a cause for. I truly believe that there are teeth that are symptom free that are just waiting for a dentist to touch them with a bur. Then all hell breaks loose and the patients claim that their teeth were fine until the dentist touched them. Many of these end up with endo, which makes patients really upset.

I have a few suggestions. Some will seem simplistic, and others are from my experience of practicing a long time.

1) If you are prepping a crown on a tooth with an old amalgam, be sure to remove all the amalgam. 999 of 1,000 teeth that have old leaky amalgams will have decay under them that does not show up on X-rays.

2) After all decay is removed, place a resin modified glass ionomer (GC Fuji LINING LC, 3M Espe VITREBOND PLUS). The RMGI will chemically adhere to the dentin, is a great desensitizer, and will release fluoride if there is leakage in the future, thus protecting the tooth from more decay and a future RCT.

3) Etch the RMGI, place an adhesive (Kerr Optibond, DMG America TECO), then place a composite build-up (Kuraray Photo Core, Premier CompCore AF). Now prep the tooth as you normally do, preferably with a shoulder prep with no bevels on the margin.

4) After impressions, place a well-fitting bisacryl temporary (3M Protemp Plus, Caulk Integrity, among others, but be sure to select a 1 to 10 mixing ratio product). Do NOT use any powder liquid-type materials for temps — these are often the cause of post op sensitivity. Cement the temp with a resin temporary cement (Caulk TempGrip, Ivoclar Vivadent Systemp Link, Premier Next Temp).

5) When the patient returns to seat the crown, ask if there was any sensitivity. If the answer is yes, question the cause. If there was sensitivity, I would treat the tooth for it (Heraeus Kulzer Gluma, but since their patent has run out, many companies have a comparable desensitizer, such as Dentsply Caulk Calm-It). Numb the tooth, try-in the crown, check occlusion and fit, remove the crown, isolate the tooth, air dry but do not desiccate, and use an RMGI Cement (3M RelyX Luting Plus, GC FujiCEM in paste pak or automix).

6) Be sure to read the directions for all the products you use and follow the instructions. When in doubt, always read the instructions.

I practice with my clinical assistants before using a new product to assure that all of us know the proper use of the materials. I then rely on my assistants to prompt me in the proper sequence of the materials. Then I can concentrate on restoring the tooth, confident that I am properly using the materials. My assistants are my clinical partners in every procedure. They even wear magnification (Orascoptic or SurgiTel) so they can really see what I’m doing.

I know that if you have a system in place and follow it without omitting any steps, you will solve your sensitivity problems.

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