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OBJECTIVES: The aim of this study was to evaluate the amount of the residual cement excess after cementation and cleaning of implant-supported restorations with various positions of the margins. MATERIAL AND METHODS: Twenty-five casts with embedded implant analogs and flexible soft-tissue imitation were used in the study. Individual abutments with different position of the margin - from 1 mm supragingivally to 3 mm below the gingival level - were modelled and divided equally into five groups. The same amount of polished metal crowns was luted to prosthetic abutments, excess cement was cleaned and the restorations were removed for evaluation of the undetected cement remnants. All quadrants of each specimen were photographed for calculation of the ratio between the cement remnants area and the total specimen area using Adobe Photoshop. Afterwards, cement remnants were cleared from each specimen and weighed with analytical balances. RESULTS: The measurements in all the groups consisted of (1) the relation between the cement remnants area and the total area of the specimen; and (2) cement excess weight in grams after cleaning: group 1 (0.0111 ± 0.021; 0.0003 ± 0.0001 g); group 2 (0.0165 ± 0.019; 0.0008 ± 0.0003 g); group 3 (0.0572 ± 0.028; 0.0013 ± 0.0005 g); group 4 (0.1158 ± 0.054; 0.0051 ± 0.0013 g); and group 5 (0.1171 ± 0.059; 0.0063 ± 0.0021 g). Results showed significant increase of undetected cement quantity, as the restoration margins were located deeper subgingivally, using weighting (P=0) and calculation of proportion (P=0). There was a significant correlation between evaluation techniques (r=0.889; P=0). CONCLUSIONS: The amount of residual cement after cleaning increased as the restoration margins were located more subgingivally.
Linkevičius et al. (Tue,) studied this question.