Evaluation of the Effect of Ozonated Oil on the Healing of Palatal Donor Area of Free Gingival Grafts.

Study design This is a prospective longitudinal clinical trial, being a patient-centered, double-blind (patient and examiner), randomized by lottery, placebo-controlled study. The intention will be to serve patients at the dental clinics of the Nova Friburgo Health Institute, however, due to the pandemic, provisionally, until the calls return, some patients will be treated in a private dental office. Research volunteers will be attended to, complying with all biosafety procedures and will receive all care free of charge, in addition to the acrylic plate to be used after surgery, as well as all materials to be used before and after the procedure, as well as such as pain control medications.

Participants eligible for inclusion criteria will be invited to participate in the research, voluntarily, after clarifying doubts about the project and will sign an informed consent form. All principles of this study will be established in accordance with the Declaration of Helsinki. The study protocol will be analyzed and must receive approval from the research ethics committee of the health institute of Nova Friburgo-RJ, Universidade Federal Fluminense.

Sample calculation The sample calculation was performed considering the primary outcome. Considering the t test for two independent samples regarding the residual healing area in square milimetersl in the ozone group (36.04 ± 9.66) vs. control (48.21 ± 13.2) at 14 days (80% power; alpha level of 0.05), a sample of 14 patients per group was estimated. The program used to calculate the sample size was BioEstat 5.3 (Mamirauá , Belém, PA, Brazil).

Clinical groups and procedures Epithelial free gingival tissue (EGL) grafts will be removed from the palate to be placed in a post - extraction socket in order to achieve ridge preservation. Both procedures, extraction and obtaining the EGL, will be performed in the same surgical procedure. In the first surgical step, the tooth will be extracted using atraumatic instruments . In the second step, the EGL will be removed from the palate, in a standardized way, using a circular scalpel with 8 mm in diameter and 2 mm in thickness (Maximus Instrumental Odontológico®, Contagem, Brazil). The EGL will be adjusted at the entrance of the alveolus and sutured with 5.0 non-resorbable monofilament nylon thread (Ethicon ®, Johnsons & Johnsons do Brasil®, São José dos Campos, São Paulo, Brazil).

The donor area will be sutured with non-resorbable 4.0 polypropylene thread , considering that this thread is a monofilament thread , in order not to accumulate bacterial biofilm (Ethicon ®, Johnsons & Johnsons do Brasil ®, São José dos Campos, São Paulo, Brazil) . After suturing, the patient will receive a 1 mm thick acetate plate that covers part of the donor area of the palate, providing protection to the palatal wound against mechanical trauma. The suture from the palatal region will be removed at 7 days, while the suture from the recipient area will be removed at 14 days. Only the donor area will be evaluated in the present study.