###### Abstract  
Aim: To analyze and compare the effectiveness of two antibacterial gels in the treatment of mucositis. Methods: After signing the informed consent, in accordance with the Helsinki Declaration of 1975, revised in 2000, 21 patients were included in the study and divided by randomization into two groups. At the baseline, the modified bleeding index (mBI) and plaque index (PI) values were measured, and an oral hygiene and implant disinfection session was carried out. The session was repeated at 7, 15, and 30 days and after 2 and 3 months from the baseline. Two products were used--a bioadhesive gel in the test group and a 1% chlorexcidine gel in the control group. Results: Due to three dropouts, the final sample was composed of 18 patients. An improvement in periodontal indices was observed, similar to mBI and PI values, in both groups. There were no complications except for the appearance of pigmentations in the control group. Conclusions: The antibacterial power and effectiveness of the two gels are comparable. Considering the small sample size of the study cohort, further studies are needed to validate the results obtained from this pilot study.  
peri-implant health; plaque control; bleeding index; plaque index; peri-implant mucositis; chlorhexidine; cetylpyridinium chloride; triclosan; dental implant 202331328  
One of the most documented methods for the treatment of mucositis is non-surgical therapy, which involves the mechanical breakdown of bacterial biofilm, the removal of the irritant factors present inside the peri-implant sulcus, and the decontamination of the implant surface using antibacterial solutions [2; 9; 10; 11].  
This therapy must be combined with proper oral hygiene at home and a program of periodic professional checks in order to verify the qualitative status of the marginal seal [12].  
In the literature, many useful active ingredients have been suggested for the disinfection of implants, including chlorheximide at different concentrations and formulations and different antibiotics with topical or systemic administration [13].  
Chlorheximide has small contraindications if used for a fairly long period of time, such as those required for the treatment of mucositis. Among the most frequent are the appearance pigmentation on the tongue, dental surfaces, and prostheses and a marked alteration of taste [14]. It would therefore be necessary for a treatment to contain active ingredients that the patient can use even for medium-long periods without contraindications.  
The objective of this study is to evaluate the healing of peri-implant tissues affected by mucositis with a non-surgical treatment protocol comparing two different methods. In the control group a gel containing 1% chlorheximide was used, whose antiseptic power has now been validated with numerous scientific trials [14; 15], while in the test group a bio-adhesive gel with natural active ingredients was used.  
The test gel contains antibacterial substances, Cetylpyridinium chloride and essential oils of Manuka and Melaleuca and re-epithelial substances, including the same essential oils; hyaluronic acid at different molecular weights, including molecule oligomers; and a PVP/hydrogen peroxide complex. It also has a marked bio-adhesion thanks to a complex original system of natural gums and resins (Ca/Na PVM-Ma copolymer). In addition, in its interior there are soothing substances, such as allantoin, bisabolol, and vitamin E.  
Cetylpyridinium chloride is a cationic quaternary ammonium compound [16]; its effectiveness has been demonstrated in the control of gingival plaque and in case of gingivitis [17; 18; 19].  
The null hypothesis for this study is that there is no difference for mBI and PI between the two processing protocols used.