Contamination of the zirconia surface by components of mixed saliva and its control by X-ray photoelectron spectroscopy. Part 2. Influence of the functional monomer MDP-10

INTRODUCTION. The strength of adhesive luting of zirconia restorations largely depends on the surface state. Primers based on the functional monomer 10-methacryloyloxydecyl dihydrogen phosphate (MDP-10) provide chemical bonding of the adhesive to the oxide surface; however, during try-in the framework contacts mixed saliva, whose organic components may adsorb onto the surface. The effect of prior MDP-10 application on such contamination and its subsequent removability is insufficiently studied.

PURPOSE. To study the influence of the functional monomer MDP-10 on the elemental composition of the zirconia surface and on the resistance of the MDP-10-primed surface to salivary mucin contamination using X-ray photoelectron spectroscopy (XPS).

MATERIALS AND METHODS. Yttria-stabilized zirconia (Y-TZP) plates were examined in three states: after application of an MDP-10 solution in isopropanol (MDP-10); after subsequent application of a mucin model (MDP-10 + mucin); and after mucin application followed by distilled-water rinsing (MDP-10 + mucin + rinsing). Atomic concentrations of C, N, O, and P were determined by XPS (PREVAC EA15, Al Kα, hν = 1486.6 eV) and the P/N ratio was calculated (n = 6 per group). Data were analysed by one-way ANOVA with Tukey post-hoc test.

RESULTS. The MDP-10-primed surface showed a pronounced phosphorus signal (P = 7.24 ± 0.12 at.%) with low nitrogen content (N = 1.10 ± 0.05 at.%; P/N = 6.59 ± 0.36). Mucin application increased nitrogen to 2.42 ± 0.05 at.% and reduced P/N to 2.96 ± 0.08 (p < 0.001). After rinsing, nitrogen returned to the level of the MDP-10-primed surface (1.12 ± 0.05 at.%; no difference from the MDP-10 group, p = 0.77), and P/N largely recovered (5.84 ± 0.34). The phosphorus signal persisted in all groups.

CONCLUSION. MDP-10 forms a stable phosphate-containing layer on the zirconia surface. Salivary mucin adsorbs on top of the MDP-10 layer but, unlike on the untreated surface, is effectively removed by water rinsing, with nitrogen returning to baseline. MDP-10 priming increases the resistance of the surface to irreversible organic contamination, which is relevant to the protocol of preparing restorations for luting.

1. Zarone F., Ruggiero G., Leone R., Breschi L., Leuci S., Sorrentino R. Zirconia-reinforced lithium silicate (ZLS) mechanical and biological properties: A literature review. J Dent. 2021;109:103661. https://doi.org/10.1016/j.jdent.2021.103661

2. Ghodsi S., Jafarian Z. A review on translucent zirconia. Eur J Prosthodont Restor Dent. 2018;26(2):62–74. https://doi.org/10.1922/EJPRD_01759Ghodsi13

3. Bruhnke M., Awwad Y., Müller W.D., Beuer F., Schmidt F. Mechanical properties of new generations of monolithic, multi-layered zirconia. Materials. 2022;16(1):276. https://doi.org/10.3390/ma16010276

4. Aziz A.G.A. The Effect of Artificial Aging (LTD) on The Mechanical and Optical Properties of Conventional and Translucent Zirconia for Fixed Prosthodontics [PhD thesis]. Leeds; 2018.

5. Zadorozhnaya O.Yu. Development of the composition and technology of wear-resistant alumina–zirconia ceramics resistant to low-temperature degradation [Dissertation Abstract Cand. Sci. (Eng.)]. Tomsk; 2022. 25 p. (In Russ.).

6. Sakhabieva D.A. Application of zirconia dental crowns using speed-sintering technology [Dissertation Abstract Cand. Sci. (Med.)]. Moscow; 2022. 24 p. (In Russ.).

7. Llaka E. Functional and esthetic aspects of dental prosthetics with monolithic zirconia constructions in the esthetic zone supported by teeth or implants [Dissertation Abstract Cand. Sci. (Med.)]. Moscow; 2023. 23 p. (In Russ.).

8. Kasem A.T., Ellayeh M., Özcan M., Sakrana A.A. Three-year clinical evaluation of zirconia and zirconia-reinforced lithium silicate crowns with minimally invasive vertical preparation technique. Clin Oral Investig. 2023;27(4):1577–1588. https://doi.org/10.1007/s00784-022-04779-1

9. Ismailov F.R. Clinical and laboratory substantiation of the application of methods for optimizing endodontic treatment [Dissertation Abstract Cand. Sci. (Med.)]. Moscow; 2023. 25 p. (In Russ.).

10. Miura S., Tsukada S., Fujita T., Isogai T., Teshigawara D., Saito-Murakami K. et al. Effects of abutment tooth and luting agent colors on final color of high-translucent zirconia crowns. J Prosthodont Res. 2022;66(2):243–249. https://doi.org/10.2186/jpr.JPR_D_21_00025

11. Franz A., Winkler O., Lettner S., Öppinger S., Hauser A., Haidar M. et al. Optimizing the fitting-surface preparation of zirconia restorations for bonding to dentin. Dent Mater. 2021;37(3):464–476. https://doi.org/10.1016/j.dental.2020.12.001

12. Nagaoka N., Yoshihara K., Feitosa V.P., Tamada Y., Irie M., Yoshida Y. et al. Chemical interaction mechanism of 10-MDP with zirconia. Sci Rep. 2017;7:45563. https://doi.org/10.1038/srep45563

13. Yang B., Lange-Jansen H.C., Scharnberg M., Wolfart S., Ludwig K., Adelung R., Kern M. Influence of saliva contamination on zirconia ceramic bonding. Dent Mater. 2008;24(4):508–513. https://doi.org/10.1016/j.dental.2007.04.013

14. Quaas A.C., Yang B., Kern M. Panavia F 2.0 bonding to contaminated zirconia ceramic after different cleaning procedures. Dent Mater. 2007;23(4):506–512. https://doi.org/10.1016/j.dental.2006.03.008