Background. Disk displacement without reduction (DDwoR) is one of the most common temporomandibular joint disorders (TMDs); it can manifest itself in joint pain and limited mouth opening. Nowadays, many arthrocentesis techniques are used with no consensus on which technique is optimal. Objectives. The aim of this study was to investigate the efficacy of 3 techniques in the treatment of TMD known as DDwoR and to compare them in order to determine whether one is superior to the others. Material and methods. A prospective study was conducted between May 2015 and June 2018. The sample consisted of 30 adult patients (6 males and 24 females; mean age: 38.87 ±6.40 years) with DDWoR, confirmed with magnetic resonance imaging (MRI). The patients were randomly divided into 3 groups according to the treatment technique applied: arthrocentesis only (control); arthrocentesis plus hyaluronic acid (HA); and arthrocentesis plus platelet-rich plasma (PRP). The maximum mouth opening (MMO) as well as pain intensity and masticatory efficiency on a visual analog scale (VAS) were measured at the time of diagnosis (baseline) and at 1-month, 3-month, 6-month, and 9-month follow-up appointments. The significance level was set at 0.05 for all statistical tests. Results. The 3 techniques resulted in significant improvement in MMO and all VAS parameters. The one-way analysis of variance (ANOVA) revealed significant differences (p < 0.05) in the variables between the 3 groups. The increase in MMO in the PRP and HA groups was significantly greater than in the case of the control group, whereas no significant difference was found between the PRP and HA groups. The pain intensity and masticatory efficiency results were significantly better in the PRP group than in the HA group or the control group; at the same time, no significant differences were noted between the HA group and the control group. Conclusions. Despite the fact that patients benefited from all of the 3 techniques, arthrocentesis plus PRP appeared to be superior to arthrocentesis plus HA or arthrocentesis alone.