The goal of this clinical trial is to compare two periodontal regenerative treatments in adults with Stage III or IV periodontitis and infrabony periodontal defects ≥3 mm.

The study aims to determine whether hyaluronic acid and polynucleotides (Regenfast®) combined with bovine bone graft material (Bio-Oss®) provides similar or improved periodontal regeneration compared with enamel matrix derivative proteins (Emdogain®) combined with Bio-Oss®.

Researchers will evaluate:

• Periodontal healing and bone regeneration
• Changes in probing depth, clinical attachment level, gingival recession, and tooth mobility
• Radiographic bone fill
• Survival of treated teeth after 1, 3, and 5 years

Participants will:

• Receive initial periodontal treatment and oral hygiene instruction
• Undergo clinical and radiographic evaluation
• Receive minimally invasive periodontal regenerative surgery under local anesthesia
• Be randomly assigned to receive either Regenfast® + Bio-Oss® or Emdogain® + Bio-Oss®
• Attend follow-up visits with periodontal examinations and radiographs over 5 years

This clinical study evaluates two regenerative approaches used during minimally invasive periodontal surgery for the treatment of infrabony periodontal defects deeper than 3 mm. The study compares a combination of hyaluronic acid and polynucleotides (Regenfast®) with enamel matrix derivative proteins (Emdogain®), both used together with a bovine bone graft material (Bio-Oss®).

This is a randomized, multicenter clinical study conducted in three specialized periodontal clinics by experienced periodontists. Adults with Stage III or IV periodontitis who continue to have deep periodontal defects after initial periodontal treatment may be eligible to participate.

Participants will first receive standard non-surgical periodontal treatment, including professional cleaning, root planing, oral hygiene instruction, and chlorhexidine mouth rinses. Eight weeks later, a clinical and radiographic reevaluation will be performed. Patients who meet the study criteria will undergo minimally invasive periodontal surgery using papilla preservation techniques.

During surgery, the periodontal defect will be cleaned and treated with one of the two regenerative materials selected randomly through a sealed-envelope allocation process. Patients will receive either Regenfast® with Bio-Oss® or Emdogain® with Bio-Oss®. All participants will receive local anesthesia, postoperative antibiotics, pain medication, and supportive periodontal care.

Researchers will monitor healing and treatment outcomes through clinical examinations and radiographic evaluations performed at 1 year, 3 years, and 5 years after surgery. Measurements will include periodontal pocket depth, gum recession, clinical attachment level, bleeding on probing, tooth mobility, and the amount of bone regeneration seen on radiographs. The study will also evaluate long-term tooth survival and analyze whether factors such as smoking habits or defect shape influence treatment outcomes.

Inclusion Criteria:

• Adults aged 18 years or older
• Non-smokers or light smokers (fewer than 10 cigarettes per day)
• No diabetes or well-controlled diabetes
• At least one infrabony periodontal defect ≥ 3 mm in depth
• Periodontal pocket depth ≥ 6 mm at baseline (after initial treatment)
• Full-mouth plaque and bleeding scores ≤ 20%, ≤15% at re-evaluation
• Ability and willingness to attend follow-up visits for 1, 3, and 5 years
• Teeth included in the study must be healthy from an endodontic point of view or properly root-treated

Exclusion Criteria:

• Pregnant or breastfeeding women
• Patients with weakened immune systems or significant systemic diseases
• Heavy smokers (more than 10 cigarettes per day)
• Full-mouth plaque or bleeding scores >20%, >15%
• Current alcohol or drug abuse
• Patients who have received periodontal treatment within the last 6 months
• Patients unwilling or unable to attend follow-up visits required for the study