Although dental implants have a high success rate, the prevalence of peri-implantitis has been rising worldwide. Similarly to periodontitis, peri-implantis are complex infections caused by oral pathogens that colonize the oral cavity tissues. Then, several anti-infective treatments have been proposed to treat peri-implantitis. Although an ideal and definitive therapy has not yet been established, one of the most commonly used protocols is the open-flap mechanical decontamination of the implant surfaces. Nonetheless, it has been well established that after the active treatment phase, it is essential that patients enter a maintenance phase, similarly to that followed by patients who have had periodontitis. One of the main risk indicators for peri-implantitis is poor oral hygiene, so the maintenance phase should include strict control of the supra and submucosal biofilms. Several methods, including the use of dental and interdental brushes, are usually recommended for the mechanical control of biofilm accumulated in implant surfaces; however, many patients are not able to effectively remove this biofilm. Thus, the use of a chemical adjunct to traditional mechanical methods during the maintenance phase of peri-implantitis treatment could improve the long term stability of dental implants. Among the several antimicrobial agents used to control biofilm accumulation in the oral cavity, triclosan is one of the most effective. Therefore, the aim of this study was to evaluate the effects of a dentifrice containing 0.3% triclosan on periodontal and peri-implant parameters in patients, with or without periodontitis, treated for peri-implantitis and that were enrolled in a maintenance phase for two years. Subjects presenting at least one implant with peri-implantitis, received surgical anti-infective therapy consisting of mechanical debridement of the implant surfaces with scalers and sodium bicarbonate jet were entered into the study. Sixty days later (baseline), subjects were randomized into two groups: (i) brushing with a toothpaste containing 0.3% triclosan + 1450 ppm fluoride (test) or (ii) brushing with a toothpaste containing 1450 ppm fluoride (control). Subjects received clinical and microbiological monitoring at baseline, 3, 6, 12, 18 and 24 months post-therapy. 102 subjects were enrolled (test, n= 48; control, n=54) in the study. The results for peri-implant parameters showed that the control group had loss of relative clinical attachment level (CAL) over the course of the study (p\<0.05) while the test group showed stability for this parameter. The difference between groups for CAL change between baseline and 24 months (0.55 mm) was statistically significant (primary outcome variable). The red complex pathogens were only reduced in the test group at 24 months. The periodontal parameters results showed that the test group (n=39) had a greater reduction in the percentage of sites exhibiting bleeding on probing and lower levels of plaque in comparison with the control group (n=49) after 24 months of brushing with the assigned toothpastes (p\<0.05). The mean percentage of sites with probing depth ≥ 5mm was reduced over the course of the study only in the test group (p\<0.05). The data of the present study showed that a toothpaste containing 0.3% triclosan was more effective than a regular fluoride toothpaste in maintaining peri-implant clinical stability and a more beneficial subgingival microbial profile in subjects with or without a history of periodontitis, that have been treated for peri-implantitis and were enrolled in a regular maintenance program for 2 years. In addition, a toothpaste containing 0.3% triclosan was more effective in maintaining a healthier periodontal environment around natural teeth.