Every 3 months, ultrasonic instrumentation was carried out with an specific implant tip coated with Polyether Ether Ketone (PEEK), activated subgingivally and circumferentially around the implant. Then, the implants were treated with rubber cup and a polishing paste.

Rate of Presence / absence of Plaque at the implant (6 sites/implant)

Rate of Presence / absence of suppuration at the implant (6 sites/implant)

Intraoral standardised radiographs of the site of interest measured in digital intraoral radiographs using an image-processing software

Samples taken from the gingival crevicular fluid (GCF) were taken from each included implant from the deepest PD site with positive BoP, at baseline and at the final evaluation, always prior to microbiological sampling. Samples were taken using the filter paper technique. After isolation of the area with cotton rolls and gentle cleaning with air and a gauze to remove supragingival biofilm deposits and potential saliva contamination, a paper strip of standard length and height was inserted into the peri-implant pocket, until mild resistance was felt and left in place for 30 seconds. The soaked volume of GCF was measured using the Periotron 8000® device. Subsequently, the paper strips were inserted in micro-centrifuge plastic tubes and immediately stored at -80°C until further processing. Analyses were carried out using a Luminex System (Luminex® 200, Luminex Corporation, Austin, TX, USA) to determine volume of the following biomarkers: IL-1β, IL-6, IL-8 and TNF-α.

Sample from the deepest site in the evaluated implant using two consecutive sterile paper-points kept in place for 10 seconds and then transferred into a screw-capped vial, containing 1.5 mL of reduced transport fluid (RTF). Samples were transferred to the microbiological laboratory within 2 hours and homogenized by vortexing for 30 seconds and serially diluted in phosphate buffer saline (PBS). Then, 0.1 mL of each dilution was plated manually on the specific medium Dentaid-1, for the detection of Aggregatibacter actinomycetemcomitans, and incubated for 3 days in air with 5% CO2 at 37ºC. Samples were also plated into a non-selective blood agar plate, supplemented with haemine (5 mg/l), menadione (1 mg/l) and 5% sterile horse blood, with 7-14 days of anaerobic incubation.

Sample from the deepest site in the evaluated implant using two consecutive sterile paper-points kept in place for 10 seconds and then transferred into a screw-capped vial, containing 1.5 mL of reduced transport fluid (RTF). Samples were transferred to the microbiological laboratory within 2 hours and homogenized by vortexing for 30 seconds and serially diluted in phosphate buffer saline (PBS). Then, 0.1 mL of each dilution was plated manually on the specific medium Dentaid-1, for the detection of Aggregatibacter actinomycetemcomitans, and incubated for 3 days in air with 5% CO2 at 37ºC. Samples were also plated into a non-selective blood agar plate, supplemented with haemine (5 mg/l), menadione (1 mg/l) and 5% sterile horse blood, with 7-14 days of anaerobic incubation.

Sample from the deepest site in the evaluated implant using two consecutive sterile paper-points kept in place for 10 seconds and then transferred into a screw-capped vial, containing 1.5 mL of reduced transport fluid (RTF). Samples were transferred to the microbiological laboratory within 2 hours and homogenized by vortexing for 30 seconds and serially diluted in phosphate buffer saline (PBS). Then, 0.1 mL of each dilution was plated manually on the specific medium Dentaid-1, for the detection of Aggregatibacter actinomycetemcomitans, and incubated for 3 days in air with 5% CO2 at 37ºC. Samples were also plated into a non-selective blood agar plate, supplemented with haemine (5 mg/l), menadione (1 mg/l) and 5% sterile horse blood, with 7-14 days of anaerobic incubation.

Sample from the deepest site in the evaluated implant using two consecutive sterile paper-points kept in place for 10 seconds and then transferred into a screw-capped vial, containing 1.5 mL of reduced transport fluid (RTF). Samples were transferred to the microbiological laboratory within 2 hours and homogenized by vortexing for 30 seconds and serially diluted in phosphate buffer saline (PBS). Then, 0.1 mL of each dilution was plated manually on the specific medium Dentaid-1, for the detection of Aggregatibacter actinomycetemcomitans, and incubated for 3 days in air with 5% CO2 at 37ºC. Samples were also plated into a non-selective blood agar plate, supplemented with haemine (5 mg/l), menadione (1 mg/l) and 5% sterile horse blood, with 7-14 days of anaerobic incubation.