Fractal Analysis Applied to the Diagnosis of Oral Cancer and Oral Potentially Malignant Disorders: A Comprehensive Review

In nature, everything is regular and orderly arranged. The degree of derailment from geometry is related to the disarrangement of living tissues associated with diseases. In the diagnostic field, fractal analysis calculates the fractal dimension (FD), a numerical measure of the degree of regularity of a tissue or structure. As for oral lesions, fractal analysis has been reported to determine the degree of irregular tissue/vascularization derailment mathematically, and this event has been correlated with the nature of the lesion. The purpose of this paper is to evaluate the scientific literature on the fractal analysis of oral cancer and its precursors (oral potentially malignant disorders, OPMDs) to convey whether the specific fractal dimension may be predictive of cancer or the cancerous progression of OPMDs. For this purpose, three databases (PubMed, Scopus, and ISI Web of Science) were investigated according to the PRISMA checklist to answer the following query: "Is fractal analysis a support method to diagnose oral cancer and distinguish it from its precursors?" The risk of biases was also assessed. All original articles published in English were considered; letters, reviews, editorials, and proceedings were excluded.