This prospective split-mouth clinical study will evaluate the effects of different plasma systems on the early microbiological colonization of implant healing abutments after implant surgery. Written informed consent will be obtained from all volunteers prior to participation.

Before implant placement, all patients will be instructed to rinse with 0.2% chlorhexidine for 1 minute. Surgery will be performed under local anesthesia using articaine containing 1:100,000 epinephrine. Full-thickness flaps will be elevated, and implant-site osteotomies will be prepared under saline irrigation in accordance with the manufacturer's protocols. In all patients, four implants will be placed during the same surgical session. After completion of the osteotomies for all four implants, each implant site will be assigned, using the sealed-envelope method, to one of the following conditions: control, vacuum plasma, argon jet plasma, or cold atmospheric plasma. The corresponding healing abutment will then be placed, and the wound margins will be primarily sutured.

The intervention arms will be defined as control, vacuum plasma, argon jet plasma, and cold atmospheric plasma, and these operational group labels will be used in all statistical analyses. In all groups, titanium Medentika healing abutments measuring 4.5 mm in diameter and 6 mm in length will be used; no pretreatment will be applied in the control group. In the cold atmospheric plasma group, plasma will be applied for 60 seconds using the piezobrush® PZ3 device manufactured by relyon plasma GmbH (Germany), with ambient air as the working gas (electrical connection: 110-240 V/50-60 Hz; maximum power consumption: 18 W). The nozzle-to-surface distance will be standardized at 5 mm, and the application angle will be kept perpendicular. In the argon jet plasma group, the same piezobrush® PZ3 device will be used with the Multigas Module and argon gas; a flow rate of 11 L/min will be provided via the regulator, and the application time, distance, and angle will be kept identical to those in the cold atmospheric plasma group. In the vacuum plasma group, a 60-second treatment will be applied using the Plasma Active device. The nominal technical specifications of the device are as follows: dimensions, 150 × 354 × 267 mm; capacitive touchscreen IPS LCD display; 2 treatment slots; chamber dimensions, 65 × 28 mm; treatment duration, 60-120 seconds; power supply, 220 V/50-60 Hz; and power consumption, ≤200 W.

During the postoperative period, a standard care protocol will be applied to all patients; amoxicillin/clavulanate (or clindamycin in cases of penicillin allergy) will be prescribed for 7 days, ibuprofen for 3 days, and 0.2% chlorhexidine mouthwash twice daily. Sutures will be removed at postoperative week 1. At the same visit, the healing abutments will also be removed and sent for microbiological analysis, and new abutments will be placed in their position.

Inclusion Criteria:

• Patients presenting to the Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Kahramanmaraş Sütçü İmam University, for implant treatment, with edentulous areas requiring at least four implants to support a fixed prosthesis.
• Willingness to participate in the study.
• Age over 18 years.
• No allergy to any of the products used in the study.
• Non-smokers or light smokers (<10 cigarettes/day).
• Good patient compliance, adequate understanding of the study information, and provision of signed informed consent.
• Good or moderate oral hygiene.

Exclusion Criteria:

• Refusal to participate in the study.
• Need for alveolar ridge augmentation.
• Poor general health status (including immune system disorders, uncontrolled diabetes, ongoing chemotherapy or radiotherapy, history of radiotherapy to the head and neck region, alcohol dependence, drug dependence, or psychiatric illness).
• Presence of untreated periodontal disease.
• Heavy smoking (>10 cigarettes/day).
• Age under 18 years.