Wound Healing Following Extraction and Ridge Preservation in Smokers and Non-smokers

All research procedures will start after IRB approval. Patients of the Graduate Periodontics Clinic in need of extraction, bone graft and membrane will be recruited. There will be two groups (smokers and non-smokers) and their demographic and social, periodontal, surgery-related, anatomical and healing variables as well as patient-reported outcomes will be recorded at different time points (immediately before, during and immediately after surgery and 1, 2, 6 weeks and 4 months) in order to evaluate wound healing outcomes and differences between the groups. The demographic and social variables evaluated are age, gender, race, medical history, medications, smoking (via interview and breath test-smokerlyzer) and alcohol consumption (via interview). The periodontal variables are tooth mobility, probing depth, attachment level, gingival and plaque index. The surgery-related variables include intraoperative complications, duration of procedure, anesthetic amount, type and approach and operator experience. The anatomical variables are bone height and width (buccolingual and buccal dimension), bone density (in Cone Beam Computed Tomographies - CBCTs) and gingival width and thickness. The healing variables include wound opening (tested clinically and in photos), bleeding, grafting material discharge, flap necrosis, loose sutures, and temporary restoration adjustment. The patient-reported outcomes are Oral Health Impact Questionnaire-14 (OHIP-14), Visual Analogue Scale (VAS) for pain, swelling and difficulty of mouth opening. At 4 months during the implant placement appointment, a bone core will be harvested via a 3D printed surgical guide based on virtual CBCT planning. The core willl be used of microCT and histological analysis as well as total RNA extraction and RNA sequencing.

Inclusion criteria

• Adult patients (18-75 years)
• Good general health (controlled conditions)
• Smokers (≥10 cigarettes/day for ≥5 years) and never smokers. Confirmation of smoking status will be done via use of a smokerlyzer. The cut-off point for distinguishing smokers from non-smokers is 8 carbon monoxide parts per million (ppm).
• Periodontal status: periodontal health, gingivitis on intact or reduced periodontium, treated periodontitis
• Intact post-extraction bony walls or less than 50% bone dehiscence
• Distance at least 8 mm of vertical bone height between bone crest and anatomical structures (i.e. sinus floor, inferior alveolar nerve (IAN) canal, mental foramen)
• Extracted tooth root in the same three-dimensional position as the future implant placement so that the bone core biopsy can be taken from a site totally within the confines of the former tooth socket without inclusion of surrounding native alveolar bone
• Scheduled for single tooth extraction with bone graft placement and membrane

Exclusion criteria

• Uncontrolled periodontal disease
• Uncontrolled systemic disease
• Pregnancy
• Use of therapy and/or medication that impairs wound healing (e.g., bisphosphonates, steroids, chemotherapy, radiotherapy etc.)