Randomization and treatment
tooth
PLAQUE
Following baseline examination, included patients were block- randomized to either receive subgingival ultrasonic/curette instrumentation and the erythritol powder/air-polishing system (test) or conventional ultrasonic/curette instrumentation only (control). Block-size for the randomization was set to 10. The computer-generated lists were printed and packed in opaque envelopes marked by randomization numbers. Prior to treatment interventions, the sealed envelopes containing group allocation, were opened by the operator (AS). Author ML, masked to treatment assignments, performed all clinical and radiographic recordings. Operator AS, unaware of previously recorded data, performed peri-implant crevicular fluid (PCF) sampling and all treatments, which were performed at baseline and repeated at 3, 6, 9, and 12 months.Pre-treatment, each patient rinsed for one minute with a mouthwash, a combination of chlorhexidine and hydrogen peroxide, intended to reduce potential COVID-19 transmission [Following treatment of test and control implants, remaining teeth and implants in the control group were treated with ultrasonic and hand-instruments and polished using polishing paste and rubber cup. In the test group, the remaining teeth and implants were treated with ultrasonic and hand- instruments and the low-abrasive erythritol powder.Based on the percentage tooth and implant surfaces with visible plaque, the patients received individualized oral hygiene instruction at each appointment. At the end of the study, each patient was re-enrolled in an individually tailored maintenance care program in which site-specific adjunctive therapy including surgical treatment was continuously considered.