Chris Nelson, DDS

I replace a fair number of aging amalgam restorations in my practice, but not simply because they are amalgam. Many silver fillings function well for decades. My concern increases when I begin to see marginal breakdown, surrounding fracture lines, undermined tooth structure, or other signs that the tooth may be progressing toward a larger structural problem. In this case, #12 and #13 had older amalgam restorations with visible radiating fractures, but the teeth were asymptomatic and otherwise favorable candidates for direct composite.

Before removing a large restoration, I usually discuss with the patient that the final treatment plan may change once the old filling is removed. A radiograph and clinical exam can tell us a great deal, but they cannot reveal every fracture pattern. If I uncover a significant mesial-distal fracture, extensive loss of structural support, or another unexpected finding, I may recommend converting the procedure to a crown. In more concerning cases, I may stop and obtain an endodontic consultation before proceeding. This allows us to begin with a conservative plan without committing to direct composite regardless of what is found underneath.

After rubber dam isolation, the existing amalgams were removed and the fracture lines became much easier to evaluate. I do not routinely chase every visible crack until it disappears. Superficial or stable fracture lines can extend deeply into otherwise healthy tooth structure, and following them to a visible endpoint may create an unnecessarily aggressive preparation without a clear improvement in longevity. Instead, I evaluate the overall fracture pattern, remaining cusp thickness, symptoms, occlusion, and structural integrity of the tooth.

The preparations were then air abraded using SilJet with a MicroEtcher II. I primarily use SilJet to clean and roughen the preparation before bonding, but it is also useful when a small amount of residual composite or alloy remains and additional tooth removal is not desirable. The silica-coated aluminum oxide particles help prepare these surfaces for bonding to fresh composite resin. This approach was influenced in part by the adhesive dentistry techniques advocated for many years by Dr. Ray Bertolotti.

The enamel was selectively etched for approximately 10 seconds, while intentionally avoiding the dentin when possible, followed by CLEARFIL Universal Bond Quick 2. In this case, the buccal cusp of #12 was sufficiently weakened that I was concerned a sectional matrix ring could fracture it. I therefore bonded and reinforced that area with composite first, then placed the sectional matrix, wooden wedge, and separation ring once the cusp was more stable.

The restorative materials were CLEARFIL MAJESTY ES Flow Universal Super Low and CLEARFIL MAJESTY ES-2 PLT Universal. When combining flowable and packable composite, I frequently use a “snowplow” technique: a small amount of uncured flowable is placed first, followed immediately by the packable composite. The packable is adapted and sculpted into the uncured flowable, and both materials are then light-cured together. For larger restorations, this sequence is repeated incrementally.

After matrix removal, the restorations were contoured with fine diamonds and carbides and polished with ceramic polishers and diamond polishing paste. The goal was not simply to replace a silver filling with a tooth-colored material, but to preserve as much healthy tooth structure as possible, stabilize the remaining tooth, restore proper proximal contact and occlusal anatomy, and avoid more aggressive treatment when the clinical situation allows.

Direct composite is not appropriate for every large amalgam restoration, and there are situations where cuspal coverage is clearly the better option. However, with good isolation, favorable fracture patterns, and adequate remaining tooth structure, a bonded direct composite restoration can be a conservative and predictable treatment choice.