Patients with arthralgia and limited mouth opening at least 3 moths, if volunteered, will be enrolled to this group. The patients will undertake a TMJ arthrocentesis, will be recommended behavioural modifications and diet alterations.

Patients with arthralgia and limited mouth opening at least 3 moths will be enrolled to this group. The patients, if volunteered, will undertake a TMJ arthrocentesis, will be recommended behavioural modifications and diet alterations. Following the arthrocentesis procedure, the patients will be instructed an exercise regimen adopted from the current literature, and asked to perform the regimen for postoperative six weeks.

The symptomatic temporomandibular joint (TMJ), either right or left, will be anesthetized using an auriculotemporal nerve block and intracapsular anesthesia. The arthrocentesis procedure will be performed using the double-puncture technique. A 21-gauge needle will be inserted into the posterior region of the joint capsule, targeting the upper joint compartment at a point located 10 mm anterior to the tragus. A second 21-gauge needle will be introduced into the anterior region of the joint capsule, also targeting the upper compartment, at a point located 20 mm anterior to the tragus. The upper joint compartment will then be irrigated with a minimum of 200 mL of saline solution through one of the needles.

For mouth opening measurement, the distance between the incisal edges of the lower and upper first incisors will be measured using a digital caliper and will be recorded in millimeters at the end of each examination. In patients with missing teeth, the teeth on the left side will be used for the measurement. In order to determine the amount of movement of the lower jaw in the lateral direction, patients will be asked to shift their lower jaws to the right and left. The amount of displacement of the midline of the lower jaw teeth relative to the midline of the upper jaw teeth will be measured with a digital caliper. The distances obtained will be recorded in millimeters at the end of each examination.

A visual analog scale (VAS) will be used to measure pain intensity. The scale consists of a 10-centimeter straight line, with '0' at the starting point indicating no pain and '10' at the endpoint representing the highest pain level tolerable. During each examination session, individuals will mark the point on the line that corresponds to their pain intensity. The distance from the '0' point to the marked position will be measured in centimeters, with greater distances indicating higher pain intensity.

The Jaw Function Limitation Scale (JFLS-20) will be administered to patients during all examination sessions using a standardized form. This scale assesses the extent to which daily activities are restricted by TMD symptoms. It includes 20 jaw functions, each scored by the patient on a scale from 0 to 10, where '0' indicates no impact and '10' indicates extreme difficulty performing the function due to TMD. The individual scores are summed to calculate a total score, with higher scores indicating greater limitations in jaw function.