The retentive strength of three different commercial luting cements on metallic substrate: an in vitro study

Objectives: Choosing an optimal luting agent can be challenging even with skillful clinicians, proper selection of a cement should be based on knowledge of physical and biological characteristics. Therefore, the aim of this study was to evaluate the retentive strength of three different commercial luting cements on metallic crowns
Methods: Thirty extracted mandibular first molars with minimal caries, and restoration were prepared to receive a full metal crown. The teeth were divided into 3 groups based on the cement used. Each group (n=10 teeth) had a different luting cement, group A- Zinc Phosphate cement (Flecks), group B- Resin modified Glass ionomer cement (Nexus™ RMGI) and Group C- Resin cement (RelyX™ Ultimate Adhesive Resin Cement). The cementation procedure was done following the manufacturer’s instruction for all the specimens and stored for 72 hours in room temperature. The prepared teeth with the cemented crowns were immersed in thermocycling unit for 48 hours. The retentive strength using tensile test was performed in an Instron machine. One-way ANOVA is used to test for differences among the three groups at P-value ≤ 0.05.
Results: There was significant difference (P= 0.000) between the cements mean retentive strengths. The weakest retentive effect was shown by RMGI cement, for which detachment occurred at an average tensile force of 133.7 N. The strongest retentive force was found for Resin cement for which detachment occurred at an average tensile force of 401.5 N and the average detachment force for Zinc Phosphate was 244.5 N respectively.
Conclusions: RelyX™ Ultimate Adhesive Resin Cement is the most retentive cement on metallic substrate