Keratinized Gingival Defect Treatment: A Comparative Study of Decellularized Dermal Matrix, Collagen Matrix Membrane, and Autogenous Free Gingival Grafts

1. Patient inclusion: Based on the inclusion and exclusion criteria, 60 patients with keratinized gingival defects were randomly assigned into experimental groups and underwent surgery according to their group numbers.

2. Specific surgical procedure: Decellularized dermal matrix group: Before surgery, the surgical site, soft tissue biotype, and attached gingiva width at the buccal side of the alveolar crest or implant were carefully evaluated. After confirming the accuracy, local anesthesia was administered with lidocaine, and a horizontal incision was made along the mucogingival junction. A partial thickness flap was raised towards the root direction and pushed downward, leaving the periosteum and some connective tissue on the alveolar bone surface. The edge of the fixed partial thickness flap was sutured, and a certain size and width of the recipient site wound was prepared. The decellularized extracellular matrix biomaterial, which was trimmed to match the size of the wound, was placed on the surface of the connective tissue at the recipient site, closely adhered and sutured, and compressed to further fit the wound and stop bleeding. The length and width of the wound and allogeneic decellularized extracellular matrix biomaterial were recorded.

Collagen matrix membrane group: The same procedure as above was performed.

Control group: Autogenous free gingival grafts were prepared by infiltrating local anesthesia with lidocaine, and a graft was harvested from the hard palate mucosa 2-3 mm from the gingival margin between the maxillary premolars and first molars according to the required attached gingival size. The thickness of the free gingival graft was between 1.0-1.5 mm, and the glandular and adipose tissues on the graft were trimmed. The free gingival graft was then transplanted onto the surface of the connective tissue at the recipient site, closely adhered and sutured, and compressed to further fit the wound and stop bleeding.

3. Postoperative care and medication: After surgery, patients were instructed to use 0.12% chlorhexidine gluconate mouthwash for rinsing, with a dosage of 20 mL per use, three times a day, for 1-2 minutes per use.

Patients could take painkillers according to their own pain level. Recommended analgesics include ibuprofen capsules, taken after meals at a dosage of 60 mg (1 capsule) per use, three times a day, until the wound and surgical site no longer hurt.

Routine oral antibiotics were prescribed after surgery, either amoxicillin or erythromycin. The dosage of amoxicillin was 0.25g per use, three times a day, for one week; the dosage of erythromycin was 150mg per use, twice a day, for one week.

4. Postoperative follow-up: The stitches were removed 2 weeks after surgery. Patients were asked to complete a questionnaire about bleeding, swelling, pain, and the dosage of oral painkillers, and photographs were taken. Patients were reassessed at 1, 2, 3, and 6 months after surgery to record their soft tissue healing, attached gingiva width and thickness, and other clinical indicators. Aoralscan 3 intraoral scanner was used to perform 3D oral examinations to obtain aesthetic indicators such as color and shape, and photographs and digital images of the oral cavity were taken.