وضعية لقمة الفك السفلي عند مرضى سوء الإطباق الصنف الثاني نموذج أول : دراسة شعاعية باستخدام التصوير المقطعي المحوسب المخروطي

الملخص EN

Background and Objective :It has been reported in the dental literature that the mandibular condyle-toglenoid fossa relationship varies according to the different types of malocclusion.

In addition, a correlation was found between tempromandibular disorders (TMDs) and the nonconcentric condylar positions.

The purpose of this clinical study was to determine the condyle-fossa relationships in patients displaying a skeletal class II division 1 malocclusion, using cone beam computed tomography.

Methods: Study sample consisted of 18 asymptomatic patients (7 females and 11 males) in the stage of pubertal growth spurt peak, their ages average was 13 years and 5 months.

They had an increased overjet (7.2±1.9 mm), a skeletal class II (ANB=5.6o ±1.9o ), and did not receive any orthodontic treatments.

Cone Beam Computed Tomography was performed using Picasso Pro (VATECH and E.

WOO), and a three dimensional radiograph of the tempromandibular joint in the habitual occlusion position was acquired.

A standard protocol was followed in viewing and orienting the radiographs according to horizontal Frankfort plane.

To evaluate the condyle’s position in each sample, joint space index (JSI) was calculated for three (mesial, central, and distal) corrected parasagittal sections perpendicular to the condyle axis and Frankfort plane.

The One Way ANOVA was carried out to compare means of the measurements in the three studied slices.

Results:The average of anterior interarticular joint space was 1.64, 1.74, 1.73 mm for the distal , central, and mesial sections consecutively.

The average posterior space was 2.17, 2.06, 2.68 mm for the distal , central, and mesial sections consecutively.

The average of posterior joint space was greater than the related anterior joint space in the same section.

In relation to JSI, average values in all three sections were positive, 14%, 8%, 20% for Distal, central, and mesial sections consecutively.

The differences of the measurements means in the three studied slices was not significant (P > .05).

Conclusions:Mandibular condyle was anteriorlly positioned within the glenoid fossa in Skeletal Class II division 2 asymptomatic patients, therefore in the case of tempromandibular disorders (TMDs), the condylar position might be nonconcentric.