Comparative evaluation of microleakage of metallic copings luted with three different commercially available luting cements: An in vitro study

Comparison of marginal leakage and retentive strength of implant-supported milled zirconia and cobalt-chromium copings cemented with different temporary cements

Background

Few studies assessed the effect of coping material (particularly milled metal copings) on the retentive strength of cements and reported contradictory results. Thus, this study aims to assess the marginal leakage and retentive strength of implant-supported milled zirconia and cobalt-chromium (Co-Cr) copings cemented with different temporary cements.

Materials and Methods

In this in vitro study, Zirconia and Co-Cr copings were fabricated on 100 straight titanium abutments. Each group of copings was divided into five subgroups (n = 10) for the use of different cements: permanent zinc-phosphate (ZP) cement, temporary zinc oxide eugenol cement (temp bond [TB]), calcium hydroxide-based temporary cement (Dycal [DC]), polymer-based eugenol-free acrylic-urethane temporary cement (Dentotemp [DT]), and methacrylate-based temporary cement (Implantlink [IL]). The retentive strength and marginal leakage of restorations were assessed. Data were analyzed by one-way ANOVA, Tukey, and Fisher's exact tests (α = 0.05).

Results

In the Co-Cr group, the retentive strength values (in Newtons) were as follows: ZP (411.40 ± 5.19) >DC (248.80 ± 5.01) >IL (200.10 ± 5.06) >DT (157.90 ± 5.19) >TB (98.50 ± 6.88). This order was as follows in the zirconia group: ZP (388.70 ± 5.35) >DC (226.60 ± 5.08) >IL (179.00 ± 3.71) >DT (136.00 ± 4.88) >TB (78.60 ± 3.50). All pairwise comparisons were statistically significant (P < 0.001). The difference in marginal leakage was not significant among the groups (P = 0.480).

Conclusion

The type of coping material and cement type significantly affected retentive strength, but not marginal leakage, of implant restorations. Milled Co-Cr copings showed higher retentive strength than zirconia copings, and ZP cement followed by DC yielded the highest retention.

Dental Luting Cements: An Updated Comprehensive Review

The cementation of indirect restoration is one of the most important steps in prosthetic and restorative dentistry. Cementation aims to bond the prosthetic restoration to the prepared enamel or enamel and dentine. Successful cementation protocols prevent biofilm formation at the margin between tooth and restoration and minimize mechanical and biological complications. With the advancements in dental cements, they have been modified to be versatile in terms of handling, curing, and bond strengths. This review presents updates on dental cements, focusing on the composition, properties, advantages, limitations, and indications of the various cements available. Currently, dental restorations are made from various biomaterials, and depending on each clinical case, an appropriate luting material will be selected. There is no luting material that can be universally used. Therefore, it is important to distinguish the physical, mechanical, and biological properties of luting materials in order to identify the best options for each case. Nowadays, the most commonly used dental cements are glass-ionomer and resin cement. The type, shade, thickness of resin cement and the shade of the ceramic, all together, have a tangible influence on the final restoration color. Surface treatments of the restoration increase the microtensile bond strength. Hence, the proper surface treatment protocol of both the substrate and restoration surfaces is needed before cementation. Additionally, the manufacturer's instructions for the thin cement-layer thickness are important for the long-term success of the restoration.

Microleakage at Implant Abutment and Prosthesis Interface in Cemented Implant-Supported Prosthesis

BACKGROUND

Dental implants have an important role in mainstream dental practice today to restore esthetics. The present study was conducted to evaluate the microleakage at implant abutment and prosthesis interface in cemented implant-supported prosthesis.

MATERIALS AND METHODS

The present study comprised sixty replicas of abutment analog with length 5 mm, width of platform 4.8 mm, and taper 6° which were milled and divided into three groups. In Group I, nickel-chromium copings were fabricated; marginal gap was evaluated with optical microscope and luted with zinc oxide noneugenol cement, Group II with zinc polycarboxylate cement, and Group III with zinc phosphate cement. Microleakage was scored by the method used by Tjan et al.

RESULTS

The mean microleakage score in Group I was 2.5, in Group II was 1.9, and in Group III was 1.05. The difference was significant (P < 0.05).

CONCLUSION

All cements showed microleakage. Minimum microleakage was seen with zinc phosphate cement than zinc oxide noneugenol cement and zinc polycarboxylate cement.