###### Abstract  
The aim of this systematic analysis was to assess the prevalence of dental microcracks at various levels (3, 6, and 9 mm from the apex) after using instruments made with conventional, R-Phase, and M-Wire NiTi alloys and the SAF system. **Materials and Methods:** Electronic searches were conducted in the databases Embase, Cochrane Library, Scopus, PubMed, and Web of Science. To arrange search methods, \"MeSH\" terms and/or keywords typically associated with the subject were paired with the Boolean operators \"AND\" and \"OR.\" Additional searches were conducted on the websites of four separate endodontic journals. After reading the titles and excluding duplicates, 1000 of the 1343 documents originally found were eliminated. Upon reviewing the abstracts, 310 of the remaining 343 experiments were also eliminated. Based on qualifying requirements, only 13 of the remaining 33 articles were included in the qualitative review. **Results:** All systems triggered dental microcracks; however, when chemo-mechanical preparation was performed using Self-Adjusting File (SAF) and systems manufactured with R-phase technology--K3 XF and Twisted File Adaptive (TFA)--less of these defects were found when compared to those manufactured with traditional NiTi--ProTaper Universal and Mtwo--and with M-Wire--ProTaper Next, Reciproc, and WaveOne. **Conclusions:** A lower prevalence of dental microcracks was observed after using SAF and endodontic systems manufactured with R-phase. NiTi instruments; dentin microcracks; Self-Adjusting File system; martensite-wire; R-phase; ProTaper Universal files; Mtwo files; ProTaper Next files; Reciproc files; WAVEONE files; TF Adaptive files; K3 XF files +
Footnote †: journal: Applied Sciences  
radiographs, it can be present [4], and treatment is done to control the endodontic infection and avoid or preserve the integrity of the peri-radicular tissues [5]. The key step in removing the pulp or controlling the endodontic infection is biomechanical preparation [6]. It is performed by operating endodontic instruments and irrigating solutions confined within the radicular space [7]. While the cleaning and shaping processes occur concurrently and thus didactically [8], it is crucial to consider the whole process as it occurs in stages. Endodontic files are mostly responsible for shaping and mechanical cleaning of the root canal, while irrigating solutions have a chemical effect on root canals' contents [3]. Stainless steel hand files were traditionally used to shape the root canal. Due to its metallurgical characteristics, the occurrence of errors and injuries was high [9]. In the late 1980s, the invention of nickel-titanium (NiTi) alloys culminated in a breakthrough in endodontics. These files have significant advantages over stainless steel files, especially in terms of instrumentation safety [10]. The existence of a fixed taper and radial lands along the length of the active section distinguished the first generation of these instruments. The first generation NiTi rotary files included Lightspeed (Lightspeed Endodontics--1992), Profile (Dentsply Tulsa--1993), Quantec (Sybron Endo--1996), and GT System (Dentsply Tulsa--1998) [11; 12; 13]. Conventional NiTi endodontic instruments contain approximately 56% nickel and 44% titanium. The finish temperature of austenite is lower than body temperature. As a result, these instruments are mostly composed of the austenite phase and exhibit super elastic properties. Traditional NiTi endodontic instruments, on the other hand, are made using a machining procedure, which can result in surface defects. These flaws are to blame for negative effects on fracture resistance, cutting performance, and corrosion resistance of the files [14]. In 2007, Sportswire LLC (Langley, OK, USA) developed a patented thermomechanical manufacturing established with the aim of producing a more flexible NiTi alloy with improved cyclic fatigue resistance. The new NiTi alloy is known as M-Wire [15].