10 most common reasons for post-operative sensitivity with composite restorations: Why it happens and solutions to fix it

1. Reason 1: Poor dentin engagement by bonding agent. Solution A: Apply two or more coats of your bonding agent, air thinning and curing each layer individually. Solution B: Switch to a one bottle, self etch resin like 3M’s new Easy Bond that still allows you to use a rinse etch step to maximize the enamel bond. SE (Self Etch) resins are the most foolproof way to eliminate post operative sensitivity but you must also read and understand Reason #6. (see below)


2. Reason 2: Not curing the bonding agent over the dentin before placing flowable composite and paste for injection molding. Solution C: ALWAYS air thin and then light cure the bonding agent over the dentin before re-wetting the cavity with a second application of bonding agent (used as a simple wetting agent) before injecting the flowable followed by the paste. Enamel doesn’t need to have the bonding resin cured first, but dentin does. If you are unfamiliar with the Injection Molded Technique please visit the Bioclear website.


3. Reason 3: Boxy prep with bad C Factor, especially small, shallow composite restorations cut with retentive features. It is mind boggling that a conservative class I composite can cause terrible post-operative pain and on the same patient a deep restorations has no post-operative sensitivity. The problem is C factor. Please contact me for a full description of modern cavity preparations. Most schools, journals and opinion leaders are married to a cavity preparation that is a modified amalgam or silicate preparation. Those 100 year old retentive preparations do not serve modern composites, the tooth, or the clinician. Cutting and restoring a non-retentive class II composite is at once liberating and frightening. Thousands of doctors are now preparing non retentive class II’s with great success, but we remain a small minority Solution D: Cut a non-retentive prep as I have described in other documents and videos available online.


4. Reason 4: Dealing with retreatment of old boxy amalgam and composite preps. Solution E: You can always play it safe and cover all of the dentin with glass ionomer before placing the composite. Solution F: Use strategic and incremental layering of flowable to rebuild the dentin, then place the paste composite “helmet” with cusps built and cured individually to eliminate cross tooth shrinkage and then injection mold the interproximals. For severely broken down molars I would prefer to do a nice PFM. Most composite margins on cementum will microleak. Period.


5. Reason 5: Using flowable as a liner straight over the dentin without a bonding agent. This will cause bizarre and strong post-operative pain. Solution F: Always use a bonding agent which has been air thinned and light cured, or a glass ionomer base underneath flowable composite. (There are some self etching flowables that have just been introduced, check back with me in 2 years to see if they are worth trying)


6. Reason 6: Acid etching (rinse etching) the dentin before using any Self Etch bonding agent other than 3M Easy Bond. Examples: Self Etching adhesives like SE bond or Optibond FL. See solution B above


7. Reason 7: Old, contaminated, or unshaken bonding resins. Solution G and H: Get a new bottle and or check the expiration, and makes sure to shake the bottle each time you dispense a one bottle resin such as Optibond Solo Plus. (The primer and bonding agents can separate like oil and water) If in doubt email me and we will send advice for your favorite bonding resin or a complimentary sample of a bonding resin that is more foolproof.


8. Reason 8: Not following orders. Solutions I, J, and K: Make sure and agitate the bonding resin on the tooth for the time prescribed if the manufacturer calls for that. Air thinning the resin also drives off the solvents if you are using a one bottle bonding agent. Read the directions.


9. Reason 9: Inadvertent and unknowing pulp horn exposure without subsequent hemostasis. Mechanical exposure of a pulp horn is common, especially in young patients and when not using enough magnification. If pulp horn bleeding or weeping is present, placing a bonding agent will nearly always kill the pulp, even on microscopic exposures. Solution L: Use more magnification to avoid and also to identify tiny exposures. Stop the bleeding or oozing with Hemodent, sodium hypochlorite, even sterile water or saline and mild pressure. Once you think that things are dry, count to 20 to make sure it stays absolutely dry. MTA or Biodentine by Septodont show promise as direct pulp capping agents but indirect pulp caps are proven better than direct exposures in outcome studies. Composite or glass ionomer will only work as a pulp capping agent when there is absolute hemostasis. Carious exposures are very high risk to kill the pulp, although the makers of Biodentine think they can predictably treat carious exposures. Check with me in 5 years on that one, and in the meantime stick with indirect pulp caps where you cut a clean margin but leave a little “beret” of carious dentin in the middle of the cavity prep over the pulp. The pre-dentin and pulp will subsequently begin to heal the dentin. Over time the body will harden, disinfect, and dry out that little spot of soggy dentin lying next to a pulp horn. See the Journal of Endodontics 9/2010


10. Reason 10: Occlusal trauma. Solution M: Understand that composites absorb at least 1% of their volume in water after they are placed. In our new preparations, there is a larger cavosurface area covered with composite. I recommend leaving all new composites slightly out of occlusion because in 24 hours the composite will swell. Unless the restoration is in hypo-occlusion when you dismiss the patient, it will likely be in hyper-occlusion within 24 hours.