The study aims to evaluate the efficacy of ridge preservation with collagen sponge or collagen membrane in combination with collagenated bovine bone mineral in extraction sockets of periodontally diseased teeth.

The study aims to evaluate the changes of clinical and radiographic outcomes following ridge preservation with collagen sponge or collagen membrane in combination with collagenated bovine bone mineral in extraction sockets of periodontally diseased teeth. The included patients will be randomized into two groups. The patients in control group will be treated with collagen membrane + collagenated bovine bone mineral, and those in the test group will be treated with collagen sponge + collagenated bovine bone mineral. The horizontal width of ridge, the vertical height of ridge at the buccal and palatal/lingual plates, width of keratinized tissue and thickness of mucosa will be measured before surgery and at 6 months postoperatively.

Inclusion Criteria:

1. Age ≥ 18 years
2. Need for molar extraction due to periodontal disease and plan for late implantation
3. No acute infection, such as abscess or effusion
4. Presence of bone defects on at one or two socket walls, where the height of the horizontal (suprabony) component of the defect (alveolar bone crest - cement-enamel junction) is >50% of the corresponding root length and the bone height of socket walls is at least 3 mm
5. Presence of one adjacent tooth to the extraction site

Exclusion Criteria:

1. Smoking
2. Pregnancy or lactation
3. Untreated periodontal disease
4. Severe systemic conditions that contraindicate surgery (such as diabetes, heart disease, cancer etc.)
5. Under radiotherapy
6. Systemic disease or medication that influences bone metabolism and mucosal healing (such as immunosuppressants, phenytoin, bisphosphonates etc.)
7. Extraction of multiple adjacent teeth
8. Allergy to any of the materials used in the study