The purpose of this randomized controlled clinical trial (RCT) is to determine the efficacy hyaluronic acid (HA) versus enamel matrix derivatives (EMD) in the treatment of infrabony periodontal defects.

Intrabony defects associated with periodontal pockets represent a risk factor for periodontitis progression and additional loss of attachment if left untreated.

Over the years, several strategies have been implemented for their surgically reconstruction with the aim of pocket reduction and clinical attachment level gain.

Grafting of intrabony periodontal defects has been used extensively over the years incorporating various materials, including autogenic bone, demineralized allogenic bone, xenogenic and alloplastic materials. Controlled clinical studies have shown a significantly higher gain of clinical attachment and radiographic bone gain in intra-bony periodontal defects treated with open flap debridement combined with EMD when compared with open flap debridement alone.

Hyaluronic acid (HAc) is a naturally occurring linear polysaccharide of the extracellular matrix of connective tissue, synovial fluid, and other tissues. It possesses various physiological and structural functions, which include cellular and extracellular interactions, interactions with growth factors and regulation of the osmotic pressure, and tissue lubrication. All these functions help in maintaining the structural and homeostatic integrity of the tissue.

In the field of dentistry, in vitro and animal studies have demonstrated that hyaluronic acid prevents oxygen free-radical damage to granulation tissue, stimulates the clot formation , induces angiogenesis and does not interfere in the calcification nodule during bone formation.

A randomized controlled trial evaluated the effect of local application of 0.8% Hyaluronan gel in conjunction with periodontal surgery. After initial non-surgical periodontal therapy and re-evaluation, defects were randomly assigned to be treated with modified Widman flap surgery in conjunction with either 0.8% Hyaluronan gel (test) or placebo gel (control) application. Statistically, significant differences were noted for Clinical Attachment Level and gingival recession, (P < 0.05) in favor of the test sites. But non-significant results were found regarding PD, BOP and PI values (P > 0.05).

At the present time no comparative data are available about the use of HA versus EMD in treatment of infrabony defects. Therefore the aim of this study will be evaluated the effectiveness of hyaluronic acid versus enamel matrix derivatives alone in the regeneration of infrabony defects.

Inclusion Criteria:

Patient related:

• adults aged 18-65 years with periodontal disease
• sites with infrabony defects and persisting pockets [probing pocket depth (PPD) ≥ 5 mm and bleeding on probing (BOP)] at re-evaluation 6 weeks after non-surgical periodontal therapy
• full-mouth plaque score (FMPS)1 and full-mouth bleeding score (FMBS)2 < 20% before surgery
• at least one radiographically detectable infrabony lesion,3
• good physical health.

Site-specific:

• Interproximal angular defects on single-rooted teeth
• radiographic infrabony component ≥ 3 mm
• PPD ≥ 6 mm and CAL ≥ 7 mm.

Exclusion Criteria:

• relevant medical conditions contraindicating surgical interventions
• pregnancy or lactation
• tobacco smoking
• untreated periodontal conditions
• any condition associated with poor compliance or failure to maintain good oral hygiene
• acute infectious lesions in areas intended for surgery
• teeth with grade 2 or higher mobility
• restorations or carious lesions on root surfaces that are associated with the intrabony defect.