The most common cause of sensitivity (generally reversible pulpitis) after placement of composite fillings is irritation to the pulp fpllowimg the acid etching process prior to placement of the restorative composite resin.. The etching process even in shallow dentin opens the dentinal tubules which communicate with the pulp. If the tubules are left open with inadequate bonding agent (see #2), placement of composite over this area will not prevent sensitivity (especially thermal sensitivity)Improper or inadequate placement of bonding agent after the etching process prior to composite placement will also result in postoperative sensitivity. There are many generations and brands of dental bonding agents that serve 2 functions: to create a mechanical and chemical bond for the composite resin with the tooth, and also "seal" the open dentinal tubules in the process. Improper or inadequate application can result in those tubules remaining open or inadequately sealed prior to composite placement.Improper placement and curing of the composite resin can result in voids on the walls or floor of the tooth creating microleakage and sensitivity. Generally, a cavity should be filled with composite resin in a layering to prevent the voids that can occur from the "cure shrinkage" that occurs when composite hardens. While newer generations of composite resin have less and eliminated the need for this gradual filling process, most composite resins still experience some shrinkage in the catalyzation process. Also never cure the occlusal (top) first, but rather the lateral (side) walls of the restoration first since light-cured composite resin cures in the direction of the light.Occlusion (bite) is off. This happens more than you think and is not always noticed especially when many times occlusion is adjusted when the patient still has anesthesia and the 'tooth is numb.' One of the common interferences occur in the excursive (side) movements in the chewing process. While it is common to have biting sensitivity when the occlusion is not balanced, very often there is thermal sensitivity (cold) as well. I always check occlusion in a post op visit with the patient when dental anesthesia is worn off.Inadequate or incomplete removal of decay. Failure to remove all caries during the cavity preparation can precipitate postoperative sensitivity as well. Some caries is not visible to the naked eye and I recommend an anti microbial wash material be used prior to beginning the filling process.Bottom line is that sometimes the sensitivity is transient as is the case when a large or juvenile pulp is present. However, if sensitivity remains, review these five conditions and reevaluate if the restoration should be removed and replaced.
