Novel silane encapsulation system for tribochemical resin bonding to a Co-Cr alloy

Raphael Pilo, Maria Dimitriadi, Nick Silikas, George Eliades*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Objectives Encapsulated silane has been introduced in powders for tribochemical coating (SilJet Plus, SP), eliminating the need for a separate silane primer. The aim of the study was to comparatively evaluate the effect of SP on the surface properties and bond strength of a Co-Cr alloy with a resin composite. Methods Co-Cr cast alloy disks were subjected to tribochemical treatments with CoJet (CJ), SilJet (SJ) and SP. Polished specimens were used as control (CR). The alloy surfaces were studied by optical profilometry (OIP; parameters Sa,Sz,Sdr,Sci), reflection FTIR microscopy (RFTIRM; CR,CJ,SJ silanized with S-Bond), scanning electron microscopy/energy dispersive X-ray microanalysis (SEM/EDX; Al + Si coverage), contact angle with water (CW) and shear bond strength with a flowable resin composite (SBS). Statistical analysis for OIP, Al + Si coverage, CW and SBS was performed by one-way ANOVA and Holm-Sidak multiple comparison tests and by Chi-square for the failure mode (α = 0.05). Results CR demonstrated the lowest Sa,Sz,Sdr values from all sandblasted surfaces, excluding Sci of SJ. Among tribochemical treatments, no differences were found in Sa,Sz. CJ showed lower Sdr and SJ higher Sci. The peaks of Si-O- were very weak on CR, but detectable on CJ, SJ and SP, with no evidence of Si-O-CH3 groups. The ranking of the statistical significant differences in CW measurements was SP > SJ + silane > CJ + silane > CR + silane. Well-defined Al and diffuse Si distributions were found on the alloy surface following tribochemical treatments. The maximum Al + Si coverage ranged between 50 and 54% (5000×) and the random coverage between 7 and 11% (1000×, p > 0.05 for both). Tribochemical treatments showed higher SBS from CR (p < 0.05), but with no statistically significant differences among them. CR demonstrated exclusively adhesive failures, whereas in tribochemically coated groups adhesive failures ranged from 10 to 20%. Clinical significance Tribochemical treatments with encapsulated silane may be considered an efficient single-step alternative to conventional two-step systems for bonding to Co-Cr alloys, offering a significant reduction in chairside time.

Original languageEnglish
Pages (from-to)60-68
Number of pages9
JournalJournal of Dentistry
StatePublished - 1 Jul 2016


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