Purpose: Despite the high success rate of implant-supported fixed restorations in dentistry, there is a lack of evidence on the marginal seal for dental cement. Thus, this study aimed to evaluate the marginal seal of implant-supported crowns and partial dentures cemented using four different dental cements.

Materials and methods: The study evaluated the marginal seal of implant-supported crowns and partial dentures cemented using zinc phosphate, resin-modified glass-ionomer, self-adhesive resin, and noneugenol, acrylic-urethane polymer-based temporary dental cements. After cementation and thermal cycling procedures, the samples were incubated in Escherichia coli suspension for 5 days at 37°C under an aerobic environment. After debonding the restorations under sterile conditions, sterile cotton swabs were used to obtain microbial samples from the inner surface of each restoration and abutment surface. To analyze the contamination, each sample was immersed in a brain-heart infusion culture medium and incubated at 37°C for 24 hours, and then, the colony-forming units were counted and recorded.

Results: Regarding the number of colonies for Escherichia coli, the results revealed no substantial difference between the crowns and the fixed partial restorations (P = .25). However, the differences in the level of contamination between the cement groups were significant (P ≤ .001). The self-adhesive resin cement samples showed the lowest level of contamination, followed by the zinc phosphate and resin-modified glass-ionomer cements. The difference in the level of contamination between these groups was not significant. The temporary cement group exhibited significantly higher numbers of bacterial colonies in comparison to the other cement groups.

Conclusion: Self-adhesive resin cement has better biologic properties for retaining implant-supported restorations than other types of dental cement.