Micromorphology analysis after professional oral hygiene procedures on zirconia restorations: in vitro study

Objectives The aim of this in vitro study was to determine whether routine dental procedures, such as brushing and ultrasonic scaling, affect the surface microtopography of veneered and CAD/CAM milled zirconia (partially stabilized with yttrium) prosthetic restorations. Methods The samples (4 × 4 mm, thickness 2 mm; n = 36) were separated from zirconia blanks (3Y-TZP-LA). One group was veneered with ceramics (F) , and the other group of samples was CAD/CAM milled (C). Each group had two subgroups: polished (1) and glazed (2). The samples of both groups: zirconia veneered and zirconia milled were divided into 3 subgroups: 0-no treatment (control samples); a- exposed to ultrasonic scaling (with a ultrasonic scaler incorporated in a dental unit) for one minute; b- exposed to brushing with a professional dental polishing nylon brush and abrasive paste (Super Polish, Kerr) for one minute. The application of brushing or ultrasonic scaling of the samples lasted 1 min (in 10 rounds), imitating the procedure carried out over a period of 5 years. The parameters of surface micromorphology were calculated before and after simulating the given methods of the professional maintenance of oral hygiene. Scanning electron microscopy (SEM, Model JSM-6390, JEOL, Inc., Tokyo, Japan) was used to evaluate zirconia surface properties carried out at 150× magnification. Results The SEM analysis showed the greatest change in surface microtopography after the use of ultrasonic scaling on glazed zirconia samples, both veneered (88.31 μm) and CAD/CAM milled (45.38 μm) samples. Conclusions Routine methods of oral hygiene professional maintenance can damage the surfaces of glazed zirconia restorations.