Dentinal fluid movement associated with loading of restorations.

Post-operative biting sensitivity is a significant clinical problem after placement of posterior resin composites and may be due to dentinal fluid movement. The occlusal surfaces of extracted teeth were filled with amalgam (control) or various posterior resin composites, and the movement of the dentinal fluid induced by the loading of the restorations was studied. In addition, the firing of pulpal nerves induced by the loading of class 5 resin composite restorations in canine teeth of dogs was also investigated. When the entire cavity was etched with an acid gel and then filled with resin composite, dentinal fluid movement in response to loading was significantly (p less than 0.01) greater than in the amalgam-filled or unoperated controls. The dog canine tooth filled with resin composite showed firing of pulpal nerves when loaded. These results suggest that the movement of dentinal fluid induced by masticatory pressure on resin composite restorations may elicit biting sensitivity.