###### Abstract  
This study aimed to evaluate and compare the quality of matching single-cone obturation using three different single-file systems--WaveOne(r) Gold (Dentsply Sirona, Bensheim, Germany), Recipro(r) blue (VDW GmbH, Munich, Germany), and Procedile(r) (Komet Medical, Gebr. Braseler GmbH & Co. KG, Lemgo, Germany). The evaluation focused on the percentage of gutta-percha-filled areas (PGFAs), sealer-filled areas (PSFAs), and unfilled areas (PUAs) across three different sections of curved and straight root canals. Sixty extracted human teeth were categorized into six groups. Based on radiographically determined root canal curvature, thirty curved and thirty straight root canals were prepared using the single-file systems according to the manufacturers' instructions and obturated with matching gutta-percha cones using AH-Plus sealer. A total of 180 sections were evaluated digitally under the microscope and the results were statistically analyzed. The mean gutta-percha percentages for Recipro(r) blue, Procedile(r), and WaveOne(r) Gold were 83%, 82%, and 80%, respectively. No significant (\(p>0.05\)) and relevant (\(\text{n}_{\text{p}}^{2}<0.10\)) differences were found in the proportion of form-fitting gutta-percha cones between the systems in all sections. Similarly, canal anatomy showed no significant influence (\(p>0.05\)). Ex vivo, all three systems showed comparable filling quality in all sections of curved and straight canals. Therefore, it can be concluded that all three file systems, in combination with their corresponding gutta-percha points, might be reliable methods for root canal obturation. Recipro(r) Blue, Procedile(r), and WaveOne(r) Gold consistently achieved comparable obturation results across various root configurations and levels of the root canal. single-file systems; root canal obturation; single-cone obturation; reciprocating motion  
(CCW) direction and are immediately released in a clockwise (CW) reciprocating motion, rather than a rotating motion. Since the CW rotation is smaller than the CCW rotation, the instrument can advance into the root canal, reducing the risk of procedural errors (e.g., instrument fracture and canal transportation), preserving the original canal curvature effectively, and allowing the preparation of the majority of root canals without glide path preparation [6; 7]. Nevertheless, the use of a glide path in a curved canal before the reciprocating single-file system is recommended due to the reduction in apical canal transportation [8; 9]. There are several reciprocating single-file systems on the market, including WaveOne(r) Gold (Dentsply Sirona Deutschland GmbH, Bensheim, Germany), Reciproc(r) blue (VDW GmbH, Munich, Germany), and Procedile(r) (Komet Medical Gebr. Braseler GmbH & Co. KG, Lemgo, Germany), which demonstrate promising results in terms of reduced preparation time and a lower incidence of procedural errors [10; 11; 12; 13; 14]. Root canal preparation, coupled with a matching-taper single-cone obturation technique, offers a dependable means of shaping the root canal, resulting in fewer procedural errors and more satisfactory filling quality in terms of length and homogeneity, particularly in the apical third [15]. Obturated root canals using reciprocating file-matched single cones demonstrate comparable quality to other obturation techniques like lateral condensation, along with similar healing rates for apical lesions [16; 17]. They also prove to be faster than traditional lateral condensation [18; 19; 20]. Therefore, the aim of this study was to compare three different single-cone obturation techniques regarding the portion of gutta-percha-filled areas (PGFAs), sealer-filled areas (PSFAs), and unfilled areas (PUAs) across three different sections of curved and straight canals using the three different reciprocating single-file systems--Reciproc(r) blue, Procedile(r), and WaveOne(r)--for root canal preparation and their corresponding matching gutta-percha cones for single-cone obturation.