Establishment of a sufficiently wide and thick keratinized gingival/mucosal tissue cuff around teeth/implants is considered of importance for long-term stability. This can more readily be achieved by means of autogenous soft tissue grafts harvested from the palate than with soft tissue substitutes. However, this often implies the creation of an open palatal wound involving secondary intention healing. The aim of this randomized controlled, split-mouth, clinical trial is to assess the effect of a hyaluronic acid containing commercial product on wound healing and patient morbidity after palatal soft tissue harvesting. Altogether, 20 volunteers will be recruited. An individualized splint containing 2 symmetrically located contralateral cylindrical openings will be used for standardized soft tissue harvesting (6 mm in Ø, 2 mm in depth). Soft tissue grafts will be harvested randomly from the right or left side and patients will be monitored for 3 weeks followed by a 1-month wash-out period prior to harvesting the second soft tissue graft from the other side. Participants will randomly start treating the palatal wound either with the test product (GUM Aftaclear Gel, Sunstar Suisse SA, Etoy, Switzerland; 0.3%) or saline solution for 7 days to promote the healing process, which will be reversed for the second round. Patient-related outcomes (morbidity, discomfort, taste alteration, pain killer consumption), frequency of bleeding events, defect closure (area, volume), and microbial colonisation will be recorded and analysed for any differences between the control and test product. Further, in 6 additional volunteers, biopsies of the healing wound are collected in a similar fashion as described above, but with the use of a larger stent in order to harvest also pristine surrounding tissues for histological analysis; biopsies are collected up to 14 days of healing.

Inclusion Criteria:

• Age 18-65 years,
• systemically healthy,
• healthy periodontal conditions at the experimental region or conditions not interfering with proper biopsy harvesting,
• no known sensitivity to HY,
• no uncontrolled diabetes mellitus,
• no radiotherapy or chemotherapy,
• no current pregnancy or breastfeeding,
• no hormonal diseases,
• no infectious diseases,
• no autoimmune diseases or under immunotherapy,
• no systemic bone disease,
• no wound healing disorders or acute inflammatory/infectious processes,
• no systemic diseases with implications on mucous membranes (e.g., Morbus Crohn),
• no increased risk of bleeding (i.e., patient with coagulation disorders or under anticoagulant therapy, and
• no heavy smokers (i.e., no regular tobacco consumption > 10 cigarettes/day).

Exclusion Criteria:

• not meeting the inclusion criteria.