The microbial etiology of gingivitis and marginal periodontitis is unanimously accepted, but several other factors have to be considered. There are many systemic conditions with unvarying manifestations at the level of the gums and deep periodontium; leukemias have varying rates of development, and in most cases a reserved prognosis. In leukemias, periodontal lesions are caused by various microbial factors, coupled with immunological modifications characteristic of the systemic condition and sometimes exacerbated by loco-regional leukocyte infiltration. If the periodontium is free of tumoral infiltrates, then periodontal lesions are easier to treat and the results are more stable. Loco-regional tumoral infiltration requires more sustained local treatment, able to diminish the spread and delay relapse of periodontal lesions. Diagnosing tumoral infiltrates at the level of the oral cavity is therefore of great importance. Computed tomography and magnetic resonance imaging investigations are costly, especially when conducted repeatedly, and histopathological investigations are invasive and predispose to complications. A diagnostic alternative is thermographic imaging; this is useful in inflammations, infections and tumoral infiltrates, and can therefore be used in several distinct pathological medical conditions. Inflammatory and infectious lesions of the oral cavity can be treated locally, and their healing clinically objectified. In the absence of inflammation and infection, any modifications that arise could therefore be attributed with a high probability to loco-regional tumoral infiltrates. The study was conducted on 10 patients at the Fundeni Clinical Hospital, and documented pathological changes at the level of the periodontium, based on clinical, thermographic and histopathological observations. The results suggest that thermographic imaging could be used to reveal possible oral leukemic infiltrates when performed after therapeutic remission of specific infectious and inflammatory periodontal lesions.