- Email: [email protected]
Resin composite bonds to amalgam
Restorative Dentistry Resin composite bonds to amalgam Background.—Complete cusp fracture in teeth restored with amalgam restorations is relatively common, especially in posterior teeth with extensive amalgam restorations. Most cusp fractures are found in and limited to the supragingival location, making restorative procedures possible. Cusp fractures in teeth restored with amalgam are traditionally restored with either total restoration replacement or indirect restorations. Both require extensive preparations, which destroy sound tooth tissue and progressively weaken the tooth, have detrimental effects on the dental pulp, and potentially damage adjacent teeth. Some amalgam restorations with adjacent cusp fractures may have an extended lifespan through the use of repair procedures. These involve cusp replacement with or without partial replacement of the amalgam restoration and preserve the part of the restoration that has no clinical or radiographic evidence of failure. This is a more conservative approach and offers the advantages of retaining more tooth tissue, reducing the risk of iatrogenic damage, reducing the need for local anesthesia, offering a possibly enhanced patient experience, and saving both time and resources. Using resin composite as the repair material also offers esthetic and structural benefits. The quality of the interfacial bond between the amalgam and the resin composite repair material is an essential ingredient in the success of these repairs. The effects of various amalgam surface conditioning methods on the tensile bond strength (TSB) between amalgam and a nanohybrid resin composite restorative material were investigated. Various intraoral restoration repair systems were used. In addition, the type of interfacial failure was noted through scanning electron microscopy (SEM) and profilometry examinations of the involved surfaces. Methods.—The 160 Gamma 2 amalgam specimens were randomly assigned to one of eight conditioning groups, as follows: group 1, air abrasion, alloy primer, and Panavia 21; group 2, air abrasion and Amalgambond Plus; group 3, air abrasion and All-Bond 3; group 4, diamond bur, alloy primer, and Panavia 21; group 5, diamond bur and Amalgambond Plus; group 6, diamond bur and All-Bond 3; group 7, silica coating technique; and group 8, nonconditioned amalgam surfaces (control). Resin composite material was then added to the substrate surfaces. TBS tests were done, then SEM and profilometry were performed on representative samples to determine the type of failure that occurred. Results.—Surfaces conditioned with alumina sandblasting and use of alloy primer and Panavia 21 had
significantly greater bond strength values than the other combinations. The specimens treated with All-Bond 3 had significantly lower bond strength values than the other groups with alumina sandblasting. Bond strength values were similar between the specimens that were sandblasted and conditioned with All-Bond 3 and the specimens that were conditioned using bur roughening of the amalgam. Bond strengths of specimens prepared with the CoJet system were similar to those prepared with the diamond bur Panavia system and those prepared with the diamond bur Amalgambond Plus. SEM found that all specimens failed adhesively. Surface roughness review noted that the roughness of specimens prepared using alumina sandblasting was significantly less than that of samples prepared using the diamond bur. The lowest degree of surface roughening was achieved using CoJet silicatization. Discussion.—Repair procedures have many advantages over total restoration replacement or tooth preparation for a cast restoration. For cusp fracture in teeth restored with amalgam, veneering the amalgam with tooth-colored material offers the potential advantage of better esthetics. The various intraoral adhesive repair systems and surface treatments differed with the surface roughening and product used. The mean TBS was highest with conditioning by air abrasion and use of the Panavia 21 adhesive system.
Clinical Significance.—The TBS of resin composite to amalgam differs with the surface roughness and type of conditioning technique used. Combining alumina sandblasting of the amalgam surface and the use of the Panavia 21 adhesive system offered significantly greater TBS than the other repair protocols investigated. Interfacial failure was adhesive in nature no matter which method was used.
Blum IR, Hafiana K, Curtis A, et al: The effect of surface conditioning on the bond strength of resin composite to amalgam. J Dent 40:1521, 2012 Reprints available from IR Blum, Univ. of Bristol Dental Hosp. & School, Lower Maudlin St., Bristol BS1 2LY, United Kingdom; e-mail: [email protected]
Volume 58
Issue 5
2013
269
significantly greater bond strength values than the other combinations. The specimens treated with All-Bond 3 had significantly lower bond strength values than the other groups with alumina sandblasting. Bond strength values were similar between the specimens that were sandblasted and conditioned with All-Bond 3 and the specimens that were conditioned using bur roughening of the amalgam. Bond strengths of specimens prepared with the CoJet system were similar to those prepared with the diamond bur Panavia system and those prepared with the diamond bur Amalgambond Plus. SEM found that all specimens failed adhesively. Surface roughness review noted that the roughness of specimens prepared using alumina sandblasting was significantly less than that of samples prepared using the diamond bur. The lowest degree of surface roughening was achieved using CoJet silicatization. Discussion.—Repair procedures have many advantages over total restoration replacement or tooth preparation for a cast restoration. For cusp fracture in teeth restored with amalgam, veneering the amalgam with tooth-colored material offers the potential advantage of better esthetics. The various intraoral adhesive repair systems and surface treatments differed with the surface roughening and product used. The mean TBS was highest with conditioning by air abrasion and use of the Panavia 21 adhesive system.
Clinical Significance.—The TBS of resin composite to amalgam differs with the surface roughness and type of conditioning technique used. Combining alumina sandblasting of the amalgam surface and the use of the Panavia 21 adhesive system offered significantly greater TBS than the other repair protocols investigated. Interfacial failure was adhesive in nature no matter which method was used.
Blum IR, Hafiana K, Curtis A, et al: The effect of surface conditioning on the bond strength of resin composite to amalgam. J Dent 40:1521, 2012 Reprints available from IR Blum, Univ. of Bristol Dental Hosp. & School, Lower Maudlin St., Bristol BS1 2LY, United Kingdom; e-mail: [email protected]
Volume 58
Issue 5
2013
269