Qualitative Evaluation of the Effects of Professional Oral Hygiene Instruments on Prosthetic Ceramic Surfaces

During professional hygiene procedures, different instruments used may cause various damage to dental prostheses. Deplaquing and scaling with curettes and ultrasonic instruments may inadvertently increase the surface roughness of the material and the risk of future bacterial adhesion and/or also compromise the marginal seal of the prosthesis. Hence, the aim of this study was to assess the qualitative effects of two types of curettes and one piezoelectric instrument with a stainless-steel tip on three types of metal-free samples. After treating the samples with different instrumentations, they were analyzed using the scanning electron microscope and then underwent a qualitative microanalysis by using a spectroscopy machine. All the materials tested in this study have undergone significant changes of their superficial structure after instrumentation both with mechanical and manual instruments. Plastic curettes appeared to be less aggressive than the other instruments. Disilicate samples show a significantly lower degree of surface glazing erosion compared to the zirconia sample with all the instruments used.

Comparison of the Shear Bond Strength of Acid Etched and Er,Cr:YSGG Laser Irradiated IPS Empress II and Feldspathic Ceramic Surfaces to Metal Brackets: an in-Vitro Study

In this experimental study, the effects of Er,Cr:YSGG laser on the shear bond strength (SBS) of brackets bonded to two ceramic surfaces (Feldspathic and IPS Empress II) were compared to hydrofluoric (HF) acid etching. 60 ceramic discs were prepared, including two groups: Feldspathic and IPS Empress II surfaces. In each group, the following subgroups were prepared: 2W Er,Cr:YSGG laser, 2.5W Er,Cr:YSGG laser, and HF acid-etching. Ceramic primer and adhesive resin composite were applied and then light-cured to bond the ceramic cylinders to brackets. The samples were stored in distilled water for 24h and then, thermocycled. SBS testing was performed with a universal testing machine. Two-way ANOVA was used to compare SBS among subgroups (P<0.05). The highest SBS was seen in feldspathic surfaces with HF preparation (14.61±3.11MPa). There was a significant difference in SBS between different surface treatments except between the laser groups of IPS Empress II. Also, feldspathic surfaces had significantly higher SBS than IPS Empress II in all groups except HF. Conventional surface treatment provides much stronger adhesion than laser regardless of the ceramic type. Er,Cr:YSGG laser is effective on the SBS of the feldspathic ceramics, but not in IPS Empress II ceramics. So, laser treatment can be recommended as a favorable setting for treating feldspathic surfaces.

Validation of Antibacterial Systems for Sustainable Ceramic Tiles

Ceramic tiles are bacteriostatic materials; however, the COVID-19 emergency has pushed tile producers to improve surfaces’ antibacterial properties. The aim of this work was to validate a silver-based antibacterial treatment applied to porcelain stoneware tiles based on natural and waste materials, thus correlating surface functionalization to tile composition and relevant physical, microstructural, and textural parameters. The treatment was applied before firing, with and without a polymeric primer. Antibacterial activity tests, stain resistance tests, and contact angle measurements were carried out on fired tiles. Further investigations were made by SEM and optical profilometry in order to study the morphological–structural profile of tile surfaces. Results showed strong antibacterial activities for all the functionalized tiles, which were mainly correlated to the morphological and textural parameters of ceramic surfaces, as well as the presence of the polymeric primer.