# Cold Atmospheric Plasma Treatment of Zirconia to Improve Its Bond Strength and Longevity with Dental Cement

## TL;DR

Cold plasma treatment improves the bond strength and durability of zirconia in dental applications by making its surface more reactive.

## Contribution

This study demonstrates that argon cold atmospheric plasma treatment significantly enhances zirconia's bond strength with dental cement.

## Key findings

- CAP treatment increased initial micro-shear bond strength to 38.3 MPa, compared to 21.6 MPa without treatment.
- CAP-treated zirconia showed 191.2% higher bond strength after 30 days of water storage.
- CAP-treated zirconia had 30.5% higher bond strength after 1000 thermal cycles.

## Abstract

Zirconia restoration debonding is one of the common issues in its dental applications because of its dense and chemically inert structure that is difficult to bond to. In this study, plasma treatment of zirconia was performed to improve its bond strength and longevity with dental resin cement. Sandblasted zirconia specimens were treated using argon cold atmospheric plasmas (CAPs), followed by applying a thin layer of 10-MDP primer, dental resin cement with light curing. Micro-shear bond strength (µSBS) test results showed that 300 s of CAP treatment significantly increased the initial µSBS to 38.3 ± 5.6 MPa as compared with the 21.6 ± 7.9 MPa without CAP treatment. After 30 days of storage in 37 °C deionized (DI) water, CAP-treated zirconia specimens had 191.2% higher bond strength than the bonded specimens without plasma treatment. After 1000 cycles of thermal cycling (TC) between 5 °C and 55 °C, the CAP-treated zirconia specimens gave 30.5% higher bond strength than the bonded specimens without plasma treatment. Surface–water contact angle measurements indicated that the zirconia surface became much more hydrophilic but showed rapid hydrophobic recovery within the first hour of CAP treatment, indicating the importance of promptly applying the primer after the plasma treatment. These findings suggest that the argon CAP technique is effective in the surface preparation of zirconia for enhancing bond strength and longevity with dental cement.