Complex Amalgams Retained by Pins, Amalgapins and Amalgam Bonding Agents

Objective: Compare resistance of complex amalgam restorations retained by either 4 regular TMS pins (a), 4 amalgapins 2mm deep and 1mm in diameter (b), Amalgambond Plus (c), Amalgambond Plus with HPA (d), Scotchbond Multipurpose Plus (SBMP)(e), PQ Amalgam (f), Panavia F 2.0 (g), All Bond 2 (h), and Resinomer (i). Method: Ninety caries free third molars were embedded in acrylic resin and their occlusal surfaces reduced to within 2 mm of their CEJ. Tytin was hand condensed in to copper band matrices reinforced with modeling compound after placement of mechanical retention or application of the amalgam bonding agents. Modeling compound and copper bands were removed after 24 hours and the restorations adjusted to produce specimens (n=10) 5mm in height with a 1mm bevel on the axial-occlusal surface. Specimens were stored in 100% humidity for one month followed by immersion in de-ionized water for 24 hours at 37 degrees Centigrade. Specimens were loaded in compression at a 45 degree angle in an Instron Universal Testing Machine at a crosshead speed of 0.02 inches/min. Results: mean failure load and S.D. were as follows: Amalgambond Plus with HPA 2159N (376), SBMP 1896N (375), 4 Amalgapins 1769N (343), PQ Amalgam 1657N (274), Panavia F 2.0 1622N (442), Amalgambond Plus 1566N (386), 4 TMS Pins 1325N (406), All Bond 2 1300N (393), and Resinomer 1245N (309). Conclusion: An one-way ANOVA and Tukey post hoc analysis indicated the following groups were statistically similar p<0.05 (b,d,e,f), (b,c,e,f,g), and (a,b,c,f,g,h,i). All amalgam bonding agents were statistically equal to either 4 TMS pins or 4 amalgapins.