The aim of this study is to compare the effectiveness in periodontal regeneration of cross-linked hyaluronic acid at 1.8% (Hyadent BG®) with enamel matrix derivative (Emdogain®) in periodontal bone defects evaluating their clinical and radiographic variables.

A high molecular weight polysaccharide, hyaluronic acid, also known as hyaluronan or hyaluronate, has recently been studied as a promising mediator for periodontal regeneration. It has a significant role in mineralized and non-mineralized periodontal tissues for the functioning of its extracellular matrices. It has a multifunctional role in periodontics including the stimulation of cell migration, proliferation and differentiation and the acceleration of wound healing by stimulating angiogenesis. It is used in surgical procedures due to its osteoinductive potential. HA is a key element in soft periodontal tissues, the gingiva and periodontal ligament, and in hard tissue, such as alveolar bone and cementum. It has many structural and physiological functions within these tissues.

This research proposes two experimental groups to whom one of them will be applied cross-linked hyaluronic acid at 1.8% and another group with enamel matrix derivative, and a control group.

The investigator's hypothesis is that the hyaluronic acid shows potential for periodontal regeneration when evaluating its clinical and radiographic variables and when compared with the use of Enamel matrix derivative.

Inclusion Criteria:

1. Periodontitis stage II or III, grade A or B: based on the "Consensus report of workgroup of the 2017 World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions" Tonetti 2017. Clinical attachment loss of 3-5mm, radiographic bone loss to the middle third, loss of teeth ≤4 due to periodontitis, probing depth ≥ 6 mm.
2. At least, 20 teeth in the mouth.
3. Plaque Index (PI) < 1, following initial nonsurgical periodontal therapy and hygiene instructions.
4. At least one interproximal 2, 3-wall bone defect with moderate to deep intrabony defects (≥3mm) on the radiographs, and clinical probing depths (PD) >5mm using William's graduated periodontal probe on premolars or molars following initial nonsurgical periodontal therapy.
5. Absence of caries or overflowing restorations and periapical injuries of the target tooth.
6. Non-smokers.
7. Absence of systemic disease.
8. Negative history for pregnancy
9. No relevant medical history that contraindicate periodontal surgery.
10. All participants signed an inform consent form.
11. The participant is female or male adult of ≥ 18 years. The sample in sex will be compensated.
12. The participant is willing and able to return to the treatments and evaluations programmed throughout this clinical study.

Exclusion Criteria:

1. The participant is pregnant or lactating or plans to become pregnant within the next 6 months.
2. Heavy smoker (>10 cigarettes/day).
3. The participant takes> 4 U of alcohol / day.
4. The participant has a chronic illness or decreased mental capacity which would mitigate the ability to comply with the protocol.
5. Taking drugs that could alter the participant's response in healing or with oral concomitant manifestations that, in the opinion of the investigator, could interfere with the assessment of safety or efficacy.
6. Participants with systemic diseases that interfere with treatment such as, Diabetes mellitus, or rheumatoid arthritis.
7. Allergies to drug compounds.
8. The participant has been treated with antibiotics within 3 months before starting the study or has any other systemic condition that requires antibiotic coverage for routine periodontal procedures (eg, heart disease, prosthetic joints, etc.).
9. Participants should not have received periodontal tretment within the 6-month period prior to study.

Double-blinding: The researchers who performed the measurements will be different from those who performed the surgery; therefore, the examiner will be blinded during the entire duration of the study.