Hyaluronic Acid and Polynucleotides in Ridge Preservation

This is a single-centre, double-blind RCT involving 40 patients in need for a single tooth extraction to be replaced with a dental implant. The study consists of 11 visits, over a minimum period of 20 months. Participants will be recruited at Centro di Odontoiatria, at Università di Parma amongst patients routinely seen in new patient clinics and follow-up clinics. After atraumatic tooth extraction, participants will be randomly allocated to one of the following treatment groups: - DBBM (Bio-oss, Geistlich) mixed with a PNHA gel (Regenfast, Mastelli) and socket sealed with a porcine collagen matrix (Mucograft seal, Geistlich) (Test); - Unassisted socket healing (Control). Patient post-operative discomfort will be assessed with a visual analogue scale (VAS) and through clinician-reported post-operative oedema/swelling. Clinical evaluation of socket healing and recording of soft tissue healing index of Landry will also be performed during the early post-extraction days. With the help of a sterilecollagen sponge, wound exudate will be collected at 3, 7 and 14 days post extraction. A CBCT with a small field of view (e.g. 5X8 cm) will be taken to assess the post-extraction socket dimensions and after 4 months to plan implant placement. The CBCT scan will be processed with its embedded segmentation function to remove scattering defects and obtain the maximal possible quality.

Changes in alveolar ridge width from the extraction until 4 months post extraction between the 2 groups will be assessed with a dedicated software (e.g. SMOP) (primary outcome).

On the day of implant placement, a bone core biopsy will be collected from the drilling site. Undecalcified histology analysis will be done, and qualitative histology will be performed by a blind examiner, who will assess the level of maturation of the tissue in the two groups. Moreover, histomorphometric measurements will be recorded and presented descriptively, including amount of mineralized bone, as well as other standard parameters, such as %graft particles (test group only) and % of immature woven bone. A fully digital workflow will be followed to rehabilitate the patients, which will be followed up at up to 12 months post implant loading.

Inclusion criteria

• ≥25-year-old males and females;
• good systemic health (self-assessment);
• presence of an unrestorable/hopeless tooth with periodontal attachment and buccal bone preserved at least for 2/3rd of the root and not associated with acute periapical pathology;
• full mouth bleeding and plaque scores ≤ 25%

Exclusion criteria

• uncontrolled or untreated periodontal disease;
• history of local (head and neck) radiation therapy in the past 5 years;
• acute endodontic lesion in the test tooth or in the neighbouring areas to the extraction procedure (sites with presence of an asymptomatic chronic lesion are eligible);
• medical history that includes uncontrolled diabetes or hepatic or renal disease, or other serious medical conditions that can impact on bone metabolism (e.g. rheumatoid arthritis, osteoporosis) or transmittable diseases (e.g. HIV-related disease);
• history of alcohol or drug abuse;
• smokers of ≥10 cigarettes a day;
• self-reported pregnancy or lactation.