The purpose of this randomized controlled clinical trial (RCT) is to determine the efficacy hyaluronic acid (HA) in combination with the coronally advanced flap (CAF) for the treatment of single gingival recession site.

The hypothesis is that HA will result in improved the clinical outcomes and will reduce the pos-operative morbidity

Gingival recession is a common clinical finding in patients with high standards of oral hygiene and can be found in more than 90% of patients. Buccal exposure of roots with aesthetic impairments and dentinal hypersensitivity The ultimate goal of root coverage procedures is the complete coverage of the recession defect with an aesthetic appearance comparable to adjacent healthy soft tissues in combination with physiological probing pocket depths.Several surgical techniques have already provided good results and have been shown to attain root coverage at individual recession sites these different methods.To date, connective tissue grafts (CTG) and enamel matrix derivatives (EMD) in conjunction with a coronally advanced flap (CAF) have been shown to provide the highest probability of obtaining complete root coverage (CRC) in Miller class I and II single gingival recession as compared to CAF alone.

Hyaluronic acid (HA) is a major component of the extracellular matrix in almost all tissues. The primary role of HA is to bind water and to permit the transportation of key metabolites and therefore to maintain the structural and homeostatic integrity of these tissues.

In vitro and animal studies have demonstrated that hyaluronic acid have many properties that are essential for tissue regeneration and wound healing.

However, to the best of our knowledge, there have been limited clinical application studies in the field of root coverage procedures performed and still no consistent published data with longer follow-ups on the usage of HA are available.

Therefore, the aim of this randomized controlled clinical trial (RCT) was to evaluate the potential benefit of the adjunctive use of HA in combination with a coronally advanced flap (CAF) and to compare the outcomes with CAF alone, when treating single Miller Class I gingival recessions.

Inclusion Criteria:

• age ≥ 18 years
• full-mouth plaque score (FMPS) and full-mouth bleeding score (FMBS) < 15% (measured at four sites per tooth)
• presence of at least one buccal recession (depth ≥2 mm) classified as Miller Class I. Only gingival recession sites localized in the anterior area of the maxillary or mandibular arch (central and lateral incisors, canine and first and second premolars) and associated with aesthetic problems and/or dental hypersensitivity were enclosed
• gingival recession with at least 1 mm of keratinized tissue (KT) apical to the recession
• presence of a clearly identifiable cemento-enamel junction (CEJ), 10) no teeth with prosthetic crown or restoration with the cervical edge in the CEJ area

Exclusion Criteria:

• systemic diseases or pregnancy
• smokers
• systemic antibiotic therapy in the last 6 months
• active periodontal disease with a sites (probing pocket depth <4 mm and no bleeding on probing)
• history of mucogingival or periodontal surgery at the experimental site