Temporomandibular joint (TMJ) disk displacement without reduction (DDwoR) is characterized by abnormal displacement of the articular disk during jaw movements (Dworkin and Leresche, 1992; Poluha, et al., 2019). DDwoR can cause pain and limitations in mandibular movement (Miernik, et al., 2015). Treatment should initially involve reversible conservative approaches, and surgical interventions can be considered if initial methods fail (Al-Baghdadi et al., 2014).

TMJ arthrocentesis is a minimally invasive surgical procedure that involves washing the joint space with a biocompatible substance, without direct viewing (Nitzan, 1991; Nitzan, 2006). The goal is to alleviate pain and enhance joint function through the successful resolution of adhesions and removal of inflammatory elements (Pasqual et al., 2018; Grossmann et al., 2019a; Guarda-Nardini et al., 2021).

There are approximately 12 different arthrocentesis techniques described in the literature, essentially divided by the number of punctures performed and needles used (Şentürk et al., 2018). Classical techniques involve two punctures for the placement of two needles, ensuring that the entry and exit points of the fluid are independent, maximizing the results of the procedure (Nitzan, 1991; Grossmann and Poluha, 2021). Since 2008, the proposition of new techniques has intensified, with authors suggesting arthrocentesis with a single puncture and a single needle, making the procedure more conservative but, unfortunately, also dependent on patient cooperation (Guarda-Nardini, 2008). Another technique involves a single puncture but with a double-cannula needle, maintaining the conservative nature of a single perforation but requiring special needles (Folle et al., 2018).

With the idea of combining the conservative nature of a single puncture with the mechanical benefits of using two conventional needles, the concentric needle technique was proposed by Öreroğlu et al. (2011). This method involves the insertion of a longer and thinner needle into the interior of a shorter and thicker needle; the difference between the lumens allows the flow of fluid. This concentric needle technique has already been proven to be better than the classic two-puncture, two-needle technique, because it is less time consuming, minimally invasive, and results in better mouth opening (Kumar et al., 2020). However, the use of conventional needles limits the capacity for lumen difference and maintains the possibility of greater trauma to intraarticular tissues, since both needles have a sharp bevel. A possible solution to these limitations would be to replace the internal needle with an even thinner cannula with a rounded tip. However, no studies have evaluated the effectiveness of this concentric needle-cannula technique.

Therefore, our study aimed to compare the effectiveness of TMJ arthrocentesis using the concentric needle-cannula technique with the classic concentric needle technique for managing DDwoR. The null hypothesis being tested was that there are no differences between the two techniques.