Incorporation of Arginine to Commercial Orthodontic Luting Cements – Physical and Adhesive Properties

Objectives: White spot lesions affect more than 60% of patients undergoing orthodontic treatment. The purpose of this study was to evaluate the shear bond strength (SBS), ultimate tensile strength (UTS) and antimicrobial potential (CFU) of two orthodontic luting cements incorporated with arginine.
Methods: Method: Forty human lower incisors were separated into 4 groups (n=10): Orthocem, Orthocem + arginine (2.5 wt%), Transbond XT and Transbond XT + arginine (2.5 wt%). The brackets were fixed to the flat surface of the enamel and after 24 hours the SBS was evaluated using the universal testing machine (Instron). For the UTS test, hourglass samples (n=10) were made and tested in a mini-testing machine (OM-100, Odeme). For the antimicrobial test (colony forming unit - CFU), six cement discs from each group were made and exposed to Streptococcus mutans biofilm for 7 days and performed by serial and triplicate dilutions. Data was analyzed using two-way ANOVA, followed by Tukey's test (α=0.05).
Results: Results: SBS mean values for Transbond XT were significantly higher than Orthocem, with and without arginine (p=0.02033). Regardless of the argine incorporation, there was no significant difference in the SBS mean values within luting cement (p=0.29869). UTS of the Transbond XT was signigicantly higher than the Orthocem, and the incorporation of arginine did not influence the UTS for both resin cements. The Orthocem + arginine orthodontic resin cement significantly reducethe growth of S. mutans growth (p=0.03439), but no difference was observed for Transbond XT.
Conclusions: Conclusion: Incorporation of 2.5% arginine to two commercial orthodontic luting cements did not affect the physical and adhesive properties tested here and was effective decreasing the growth of S. mutans for Orthocem.