comparison of the level of evidence of four chapters of the reference book on oral diseases in three different editions (2003-2021)

Background: studies are assigned a level of evidence (loe) based on the methodological quality of their design, validity, and applicability to patient care. determining the loe provides insights into evidence-based dentistry (ebd), and the loe of dental education texts is important from an educational viewpoint. the present research aimed to analyze the loe of references used in four clinical chapters in three editions of an oral medicine textbook.methods: the references of the chapters ulcerative and vesiculobullous diseases, oral cancer, oro-facial pain, and cardiovascular diseases in the textbook burket's oral medicine were evaluated in three of its editions (2003, 2008, and 2021). loe was ranked according to study type and an oxford scale from 1 to 5. the chi-square test was used to compare the loe between chapters and editions.results: a total of 3136 references were assessed. the loe had the same distribution in all three editions (p = 0.000). the highest loe in all editions was the cardiovascular diseases chapter. the loe significantly increased over time between the editions for three chapters: oro-facial pain, cardiovascular diseases (p < 0.001), and ulcerative and vesiculobullous diseases (p < 0.05).conclusion: the majority of these four clinical chapters were not written using the evidence-based approach, so they had low loe. researchers must be encouraged to conduct studies with high loe, and the results of such research must also be applied in dental education textbooks.