EFFECTS OF SURFACE TREATMENTS ON AMALGAM REPAIR

Dentists are faced with clinical situations that require the decision to replace or repair an amalgam restoration. The purpose of this study was to compare five amalgam repair techniques. Six groups of 15 amalg am beams each were fabricated by mechanical condensation of Tytin into an anodized aluminum split mold. Specimens were aged for 7 days prior to repair. Repaired specimens were stored for 7 days and thermocycled 500 times. Repair strength was measured by transverse strength testin g in an Instron testing machine. Data were analyzed by a one-way ANOVA and a Student-Newman-Keuls test at the P less than or equal to 0.05 l evel. The surface treatments were: Group A) intact beams, B) roughened with a #557 bur, C) air abraded with 50 mu m aluminum oxide, D) reten tive undercuts with a #33 1/2 bur, E) Amalgambond Plus, and F) no trea tment. The repair strength of the various experimental groups ranged f rom 7-18% of the intact specimens. The #557 bur-roughened group yielde d statistically higher repair strengths than all other surface treatme nts, which were statistically equivalent to each other.