The procedures will be explained to all participants and they will be asked to sign an informed consent.~All patients will receive oral hygiene instructions and will receive phase I therapy comprising supragingival scaling and subgingival debridement.~After completion of phase I therapy the patients will be re-examined to ensure meeting all inclusion criteria. Then the participants will be allocated to 2 groups.~Group I will receive ozone therapy after harvesting free gingival graft. Group II following the harvesting of the free gingival graft, will be protected by a periodontal pack.~Surgical intervention:~Graft harvesting at donor site (Sullivan, & Atkins, 1968) To prepare the donor area, a rectangular-shape incision with 1-1.5 mm thickness will be made, and care will be taken to place most of the coronal part of the incision at least 2 mm apical from gingival margins of the upper teeth. The apical coronal dimension of the graft.~Following administration of anaesthesia by local infiltration (2% lidocaine with 1:100,000 epinephrine), a template will be placed over the palatal mucosa and will be used to outline the dimensions of the graft. The area chosen to harvest the free gingival graft will be chosen between first premolar and first molar.~The outlined graft will be carefully harvested as follows: The surgical blade entered in the contour incision, always in the posterior limit, sliding below the mucosa, and continued to find the opposite contour incision, in the anterior limit. The connective tissue surface will be carefully inspected for irregularities or adipose tissue after graft separation. Graft thickness will be immediately prepared (thinned) to obtain a graft approximately 1 to 1.5 mm thick.~The palatal wound will be protected by a periodontal pack; for the control group.~While the test group, will receive ozone therapy.~Ozone Application Protocol:~An ozone generator device (Ozone DTA-APOZAa- enterPrize Co9-Taiwan,R.0,C) with different probe numbers (#1 pointed probe,#2 pointed probe and #3 flat probe) will be used according to the manufacturer's instructions. Ozone will be applied on donor sites immediately after surgery and at days 1, 3, 7, 14 post-surgeries in the test group with output power at level 6-12 for 1 minute.~Ozone application in the control group will be simulated without starting the ozone generator.~Postoperative Protocol:~The participants will be instructed to abstain from brushing and flossing the teeth at the surgical area until suture removal (7days) and to use an antimicrobial rinse (0.12% chlorhexidine, 15 ml for 60 seconds twice daily) solution two times a day for 4 weeks.~The participants will be also instructed to consume only soft foods during the first week and to avoid any other mechanical trauma to the treated sites.~The participants will be given a prescription of Ibuprofen (600 mg every 12 hours) to be taken if necessary and the participants will be asked to record the number of tablets taken.~Participants will be enrolled in a professional plaque control program weekly for the first 4 weeks, then monthly until the end of the study.
Gaseous ozone (O3-triatomic oxygen) is the third-strongest oxidizing agent worldwide. It influences the cellular and the humoral immune system, by stimulating the proliferation of immunocompetent cells and the synthesis of immunoglobulin. Additionally; biologically active substances, such as interleukins, leukotrienes and prostaglandins which are beneficial in reducing inflammation and wound healing are orchestrated following ozone application. Given that after harvesting of a free gingival graft from the palatal donor site, healing occurs by secondary intention process; for patients with mucogingival conditions. The investigators will compare the natural process of healing at the donor site versus the healing process consecutive to ozone application; with the primary outcome is to evaluate the postoperative pain perception using visual analogue scale and to estimate the consumption of analgesics tablets after surgery.