Methods: Each patient recruited had from one to three composite restorations with visible margin discoloration. Initially, each defect was recorded with a magnified (20X) digital image through a surgical microscope. A bacterial sample was taken at the interface using a needle biopsy technique to assess for levels of mutans streptococcus. Clinical evaluation was done by two independent examiners using modified USPHS criteria for color, margin discoloration and margin adaptation. Each restoration was then randomly assigned to a control or treatment group. Control restorations were observed yearly for the presence of recurrent caries; treatment restorations were resealed by exposing the margin with a 1/4 round bur, removing all interfacial stain, acid etching, placing an adhesive bonding agent and a flowable composite to restore margin integrity. There were 152 patients recruited with 360 restorations; 180 control and 180 treatment.
Results: At four years, 110 patients were recalled (72%) with 261 restorations in place (73%); 128 untreated control and 133 resealed restorations. At that time, 35 restorations had been lost or replaced for non-related reasons. Clinical evaluation of the remaining 229 restorations determined: penetrating discoloration; control = 82%, resealed = 44% and margin crevice formation; control = 25%, resealed = 13%. Recurrent caries was diagnosed in only 5 control and 6 treatment restorations (<5%). Microscopically, 98 restorations (43%) had crevice formation. Discoloration was distributed: 28% no discoloration, 21% in the composite, 44% in the interface and 8% in tooth structure. Five-year results will be presented.
Conclusions: Resealing of restorations with margin discoloration significantly improved restoration quality over four years. Neither observing nor resealing margin discoloration influenced recurrent caries. Supported by USPHS grant DE12219.