Vertical root fractures are a major reason for extraction of endodontically treated teeth and teeth after root canal treatment are more prone to fracture compared to untreated teeth. One suggested reason for this difference is the destructive effects of some files and filling methods used during root canal treatment. However, most studies that investigated the effects of specific instrumentation and filling methodologies on the root canal walls are in vitro destructive experiments and a concern has lately been raised on the clinical relevancy of the results of these studies. Novel non-destructive methodologies and a cadaver study recently tried to challenge the concept of dentinal defects caused by instrumentation alone. This article presents an overview of the various studies conducted on the effect of endodontic procedures on the appearance of dental defects and will critically examine the evidence in light of the relevant literature.