Evaluation of the effects of different periodontal instrumentations on roughness of monolitic zirconium surfaces

Zirconia dental prostheses are widely used in dental practice. However, the effect of periodontal instrumentation and polyturing procedures performed as part of professional dental cleaning on monolithic zirconia dentures has not been fully investigated. This in vitro study aims to evaluate the effects of different periodontal instrumentation and polyturing procedures on monolithic zirconia surface roughness. 240 samples, 8x8 mm in size, prepared by cutting from zirconia blocks, were sintered according to the manufacturer's instructions. The aging procedures of the samples were carried out for 1 year and 5 years by means of Thermocycler Sd Mechatronic device. After aging, the samples were divided into five groups: control groups (n = 20), handpiece instrumentation groups (n = 60), sonic instrumentation groups (n = 60), ultrasonic instrumentation groups (n = 60) and polyture groups (n =40). While no treatment was applied to the control groups (Ka-Kb) other than aging, the handpiece, sonic and ultrasonic instrument groups were divided into three groups as the groups that did not undergo any further treatment after the first treatment (EG1a, EG1b, SG1a, SG1b, UG1a, UG1b), as the groups that were treated with paste and polyturing (EG2a, EG2b, SG2a, SG2b, UG2a, UG2b) and air-powder spraying system and polyturing (EG3a, EG3b, SG3a, SG3b, UG3a, UG3b). Polyturing was applied to the polyture groups with a paste (PG1a, PG1b) or air-powder spray system (PG2a, PG2b) without applying an instrument. The surface roughness of each sample was measured using a profilometer device and an atomic force microscope. The only group with a roughness difference in the one-year aging groups was found between PG1a and PG2a (p<0,05). The Ra, Rz and Rmax values of the one and five-year aged groups applied the same procedures were similar (p>0,05). Most of the differences in multiple comparisons of the five-year-aged groups were found between the control and treatment groups. There was a significant difference in the roughness of the UG1b-UG3b, UG2b-UG3b and EG3b-UG3b groups between the treatment groups (p<0,05). The group with high roughness that makes the difference is the group in which polyturing (UG3b) is applied with the air-powder spray system after ultrasonic instrumentation (p<0,05). Although periodontal instrumentation does not seem to affect the monolithic zirconia surface directly, its structure and roughness change when it spends a long time in the oral environment due to the nature of the material. Most periodontal treatments tend to reduce the roughness that may occur. In monolithic zirconia samples aged for five years, it was determined that the polyture increased the roughness with the air-powder spray system after ultrasonic instrumentation. It can be said that the polishing process with the paste contributes to the reduction of the roughness in general.