Presentation with PowerPoint slides has become a widely used technique in teaching. Although PowerPoint software has provided numerous features to make the presentation more effective g, poor preparation of slides could lead to lower students’ learning. The aim of the current study was to evaluate the quality of PowerPoint slides used in theoretical courses in an Iranian Dental School. A validated check-list was designed according to the criteria mentioned in papers. Teaching slides of 51 professors were collected. Slides were all put into a union file and became blind. An instructed operator filled the check-list for these union files in the same situation of classroom in Mashhad Dental School. Data were qualitatively reported. Total of 2218 slides were collected. 56.5%, 48.3%, and 30.1% of the slides had inappropriate tables and graphs, used complete sentences, had low quality images respectively. Most of the slides had appropriate font size, type, and color and the text and background had good contrast. 6.7% of the slides had misspellings and 5% had inappropriate abbreviations. According to the results of current study, some features of PowerPoint presentation were used inappropriately in the school and it have to be mentioned in faculty staff development workshops. 

Keywords: Slide; Power point; Dentistry.