In patients presenting peri-implant mucositis, effective sub-mucosal debridement is crucial to prevent peri-implantitis. The aim of this pilot study was to assess the 3-month clinical and microbiological effects of a locally delivered liquid desiccant agent with molecular hygroscopic properties, in association with sub-gingival manual debridement, in sites with peri-implant mucositis.

Twenty-three patients presenting at least one implant with no radiographically detectable bone loss, a pocket probing depth ≥ 4 mm and bleeding on probing, were included in a 3-month randomized, parallel-groups, single-blind, prospective study. At baseline (T0), patients were randomly assigned to receive a desiccant liquid agent with molecular hygroscopic properties before debridement (Test-Group), or a Chlorhexidine 1% disinfectant gel after debridement (Control-Group). Treatments were performed also after 7 and 14 days. Peri- implant soft tissues assessment (PPD, BOP, mBI, VPI, mPLI) and microbial sampling were assessed at baseline and at 3-month follow-up (T1).

A single-center, single-masked, parallel-groups, randomized clinical and microbiological study, was conducted between July and October 2018 at the Dentistry and Maxillo-facial Surgery Clinic, Department of Surgery, Dentistry, Paediatrics and Gynaecology (DIPSCOMI), University of Verona, Verona, Italy. The experimental protocol (Protocol HX-GL-ITA13, approval date 20/11/2013) was approved by the Ethical Committee of the University of Verona. The study was conducted in accordance with the Ethical Principles of the 64th World Medical Association Declaration of Helsinki and was consistent with good clinical practices. All participants signed a written informed consent.

The subjects were enrolled among individuals examined through a survey on prevalence of peri- implant infections (mucositis and peri-implantitis) in single-crown plateau-design locking-taper implants with a 3-year follow-up period. Twenty-three patients, aged between 37 and 71 years, met the study criteria.

Patients were randomly assigned (using a predefined computer-generated randomization scheme) to the Test-Group, which received the administration of a desiccant liquid with molecular hygroscopic properties (HYBENX® Oral Tissue decontaminantTM, HBX) before SRP, or to the Control-Group, which received the administration of a disinfectant gel after SRP (Chlorhexidine Digluconate CorsodylTM Dental Gel 1%, CHX).

Chlorhexidine Digluconate CorsodylTM Dental Gel 1% is an antiseptic gel with cationic nature, effective against a wide range of Gram positive and negative bacteria, favourable to the plaque control and oral inflammation prevention. HYBENX® Oral Tissue decontaminantTM is a concentrated aqueous solution of sulfonated aromatics and free sulphates. Once placed onto susceptible organic material, the product instantly absorbs free and electrostatically bonded water, denaturing the molecular structure of the organic matter. Biofilm is expected to be especially sensitive to the disruptive action of HBX solution by virtue of its porous structure and high water content. On the Test-Group of this study, HBX was administered before the Teflon-curettes debridement and left in contact with supra and sub-gingival plaque biofilm for up to 60 seconds, then rinsed with water and evacuated.

At baseline (T0) subjects were randomly assigned to the Test-Group or to the Control-Group, in order to be examined for microbial sampling, peri-implant soft tissues assessment and radiographic bone levels. The implants were consequently treated with HBX, before a SRP professional session, or CHX, after a SRP professional session. The treatment, performed by the same operator, was then repeated on days 7 and 14.

Inclusion Criteria:

- presence of at least one implant with a pocket probing depth (PPD) ≥ 4 mm, bleeding on probing (BOP) or pus on probing and no radiographically detectable bone loss (Qualifying site).

Exclusion Criteria:

• pregnant or lactating females;
• patients with severe systemic diseases, or with uncontrolled diabetes mellitus;
• assumption of agents affecting the periodontal status within 1 month prior to the study;
• use of systemic antibiotics within 3 months prior to the study;
• prophylactic antibiotics requirement;
• peri-implant specific treatments within 6 months prior to the study;
• allergy to sulphates and its derivatives.