Amalcore strength recovery following refilling of access preparations with amalgam

After endodontic treatment through an amalgam core, the recommended procedure is to replace the entire core. This study examined the strength achieved by restoring the access openings with dental amalgam and reported the type of failure during strength testing. Seventy-two Dispersalloy 8 x 8 mm cylindrical specimens were produced using controlled condensation pressures. The specimens were randomized in three groups: (1) controls, (2) 3 mm access preparations wetted with mercury-rich amalgam before restoration, and (3) 3 mm access preparations restored unwetted. The specimens tested for compressive strength were separated in two subsets. The unwetted group demonstrated significantly less strength than the control and wetted group (p less than 0.05), while the unwetted and wetted groups revealed significantly less strength than the control group (p less than 0.05). The mean diametral tensile strength recovery for the wetted and unwetted groups was 76% and 69%, respectively. The qualitative assessment of the fracture zones indicated that wetted specimens exhibited more fractures through the new amalgam core than the unwetted specimens (p less than 0.05). It would appear that amalgam refilling of access preparations through amalgam cores has clinical potential.