Comparative Effectiveness of Multiple Laser Scanning and Conventional Techniques on Zirconia Shear Bond Strength

Adil Othman Abdullah,Yi Liu,Xudong Sun,Fenik Kaml Muhammed,Yu Hui,Sarah Pollington

doi:10.3390/coatings9070422

Adil Othman Abdullah, Yi Liu + Show 4 more

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https://doi.org/10.3390/coatings9070422

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Abstract

This study aimed to compare the impact of different laser scanning with that of conventional methods on zirconia surface treatment through evaluation of shear bond strength (SBS) values. One hundred and thirty-two sintered zirconia cubic-samples were prepared and randomly divided into six study groups: milling control (without surface treatment); grinding; sandblasting; and three-times, four-times, and five-times laser scanning groups. The treatment process for the first three groups was performed before the zirconia coating, while the last three groups were treated after zirconia coating with veneer slurry through a spraying technique. In the current study, the surface roughness Ra, contact angle measurement, phase transformation, topography and interfaces, SBS in unaged and aged conditions, and fracture mode patterns of zirconia cores were investigated. The results were analyzed using laser confocal scanning microscopy, drop analyzer, X-ray diffractometry (XRD), scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS), universal testing machine and stereomicroscope. The results indicated that three-times laser scanned specimens presented higher Ra values than the other studied groups. The minimum contact angle value was detected in the mentioned group, while the control group presented the highest value. The XRD showed phase transformation from tetragonal to monoclinic t–m following grinding and sandblasting. However, the laser scanned specimens and the control group preserved the structural integrity of the zirconia core, presenting the tetragonal phase only. The highest SBS values were recorded in specimens treated with three-times laser scanning in the unaged and aged conditions. A mixed fracture was a common fracture pattern among the studied groups. The results confirmed that SBS could be optimized through three-times laser scanning and it provided better adhesion between zirconia and the veneer ceramic material. Multiple scanning processes of more than three times are not recommended for zirconia surface treatment.

Highlights

The development of dental ceramics from their inception to modern ceramic compositions, along with different technologies, dates back to the 1770s [1]
The results showed that the highest mean of shear bond strength value was achieved in group L3; 31.7 ± 2.91 MPa, while the lowest was in group L5; 24.4 ± 4.27 MPa, followed by group L4; 25.8 ± 3.68 MPa
The results indicated that L5 group presented the lowest shear bond strength (SBS) value, 22.5 ± 3.06 MPa; the highest was in L3 group; 29.8 ± 2.97 MPa, followed by S group; 28.15 ± 2.4 MPa

Summary

Introduction

The development of dental ceramics from their inception to modern ceramic compositions, along with different technologies, dates back to the 1770s [1]. Ceramics have become increasingly popular as restorative materials due to their inertness, aesthetics, and biocompatibility [1]. Ceramic materials have developed rapidly in the field of dentistry and have enabled the production of metal-free restorations, i.e., using all-ceramic materials [2]. Technological development in the dental industry, in the field of ceramic materials, has enabled the production of all-ceramic materials due to a variety of highly sophisticated approaches [2]. Improvements in all-ceramic materials provide many advantages over the metal-porcelain system in terms of mechanical and physical properties [2]

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