Improving Flexural Strength of Dental Restorative Ceramics Using Laser Interference Direct Structuring

Abstract

Zirconia and alumina ceramics restorative materials were treated with laser interference direct structuring using the third harmonic of a short pulse Nd:YAG and tested in a three‐point bending test to measure the flexural strength. The surface was restructured in a periodic line‐like pattern with controlled surface porosity and a surface composite pattern. As shown in earlier work [J. Am. Ceram. Soc. 91 [7] 2138‐42 (2008), the composite consists of two different defect states rather than different phase compositions. The resulting mechanical properties are a function of the number of laser pulses, laser energy, and angle in between the laser beams defining the periodic feature distance [Adv. Eng. Mater., 9 [7] 823–26 (2005)]. The material's fracture strength could be controlled through the three mentioned laser parameters and in an initial study significantly improved by up to 50% from initial 422 to 630 MPa for alumina and 833 to 1250 MPa for zirconia.

Direct Laser Interference Patterning of Bioceramics: A Short Review

“…At the same time, promising results have been reported on the ability to enhance the flexural strength and biological response of these materials using the same techniques. Novel developments on materials In addition to HA, alumina was also successfully patterned using DLIP [50]. This study showed that the laser treatment can even improve flexural strength of dental ceramics (alumina and zirconia).…”

“…In addition to HA, alumina was also successfully patterned using DLIP [50]. This study showed that the laser treatment can even improve flexural strength of dental ceramics (alumina and zirconia).…”

“…DLIP has been also successfully applied in zirconia substrates without undesirable changes in microstructure and it can even increase its mechanical resistance [49,50]. However, proper control of laser parameters is necessary to achieve surface textures with high feature quality.…”

“…Daniel et al [49] 8% Yttria FSZ Nd:YAG, wavelength: 355 nm, pulse duration: 2.5 ns, pulse number: 1 to 100 pulses applied, fluence: 0.2-0.9 J/cm 2 Daniel et al [50] Y-PSZ and Alumina Nd:YAG, wavelength: 355 nm, pulse duration: 2.5 ns, pulse number: 1, 10 and 50 pulses applied, fluence: 0.35-0.95 J/cm 2 Roitero et al [51] 3Y-TZP Nd:YAG, wavelength: 355 nm, pulse duration: 10 ns, pulse number: 1-10 pulses applied, fluence: 0.15-7.15 J/cm 2 Roitero et al [42] 3Y-TZP Nd:YAG, wavelength: 355 and 532 nm, pulse duration: 10 ns, pulse number: single pulse applied, fluence: 3.5 and 4 J/cm 2 Roitero et al [52] 3Y-TZP Nd:YAG, wavelength: 532 nm, pulse duration: 10 ns, pulse number: single pulse applied, fluence: 4 J/cm 2 Berger et al [53] Hydroxyapatite Nd:YAG, wavelength: 266 and 355 nm, pulse duration: 10 ns, pulse number: 1-100 pulses applied, fluence: 0.6-2.4 J/cm 2…”

The Nd:YAG dual-channel laser system with Q - modulation for direct interference lithography

“…In the last decade the direct interference lithography method utilising lasers of high power density between MW/cm 2 and GW/cm 2 has been used for periodic surface modifications of virtually any solid materials [3][4][5][6]. This method allows in a direct manner for the creation of surface structures in the micro-and sub-micron scale with a well defined long-range arrangement.…”