The intra-articular injection is considered the first line of minimally invasive treatment in temporomandibular joint with internal derangement (TMJ-ID) patients who do not respond to conservative treatment. The single-needle technique arthrocentesis has emerged to add reliability, convenience, ease the performance of the procedure, and eliminate the need for multiple punctures the Aim of this study is to assess clinical applicability and therapeutic outcomes of computer guided single needle arthrocentesis with platelet rich plasma using Shepard's cannula, in comparison with conventional free-hand technique, in the management of disc displacement with reduction of the TMJ.

A total of 24 patients with a magnetic resonance imaging (MRI) diagnosis of reducing disc displacement will be included and assigned randomly into one of two groups. Computer-guided arthrocentesis with PRP will be performed on patients in the study group using the single needle technique by Shepard cannula technique; while the conventional free hand technique will be performed in the control group. Procedure-related parameters will be assessed, while Clinical evaluation will be conducted on day 1, 1 and 3 months postoperatively.

Inclusion Criteria:

1. Patients diagnosed with internal derangement according to Wilkes stage I and II.
2. Adult patients above 18 years old.
3. Patients who would not respond to conservative treatment as a first line of treatment

Exclusion Criteria:

1. Patients with Wilkes stage III, IV, V.
2. Patients suffering from any systemic diseases, platelets function disorders, fibrinogen deficiency.
3. History of mandibular fracture.
4. Lactating, pregnant or planning pregnancy women.
5. Patients receiving anticoagulation treatment or NSAIDS within 48 hours preoperatively, corticosteroid injection at treatment site within 1 month or systemic use of corticosteroids within 2 weeks.

all data will be de-identified to protect the participant data. patients signed an informed consent for the use of their medical records and data for study

Sequentially numbered, opaque, sealed envelopes (SNOSE) allocation concealment method will be utilized. Each participant included in the study will be given a serial number that will be used in the allocation. These numbers will be written in identical sheets of paper with the group to which each participant is allocated and placed inside opaque envelopes carrying the respective names of participants. A trial independent personnel will be assigned the role of keeping the envelopes and unfolding them only at the time of the operation, so that the participant is allocated to a group which is concealed from the operator