PurposeThe aim of this work was to evaluate the effectiveness of a gel with active oxygen in the prevention of MRONJ. MethodsUsing split-mouth study design, twelve Wistar rats were used, females (n = 6) and males (n = 6). All rats received a weekly intravenous injection of zoledronate (80 μg / kg body weight in PBS) for 8 weeks. Then, the animals underwent surgery to remove the first and second right and left mandibular molars to induce osteonecrosis. The animals received topical application of oxygen gel (blue®m) on the right-side extraction site (Group T) 3 times a week until euthanasia after 6 weeks, with no intervention on the left side (Group C). The clinical parameters analyzed included the presence and dimension of bone exposure, suppuration and epithelialization. ResultsStatistical analysis using chi-square and Mann-Whitney test (p value < 0.05) demonstrated that group C had more severe signs of MRONJ at euthanasia than in the group T. ConclusionWithin the limitations of this pilot study, we can conclude that the application of active oxygen gel could be beneficial in the prevention of MRONJ.