zygoma

The zygomatic arch is the most prominent portion of the face and is commonly injured during facial trauma. It articulates with the frontal bone, temporal bone, maxilla, and sphenoid bone, and serves as the main bridge amongst these bones. Isolated arch fractures comprise 10% of all zygomatic fractures and 5% of all facial bone fractures. Treatment of zygomatic arch fractures varies from observation to open reduction. The Gilles temporal approach is a commonly used surgical technique for the reduction of zygomatic arch fractures. However, this surgical approach is associated with a facial scar in the hairline and risks of facial nerve palsy. In this research, we performed a new method using a fifty millimeter needle without surgery cut for replacement of broken zygomatic arch and evaluated the amount of pain, edema, maximum mouth opening, and ecchymosis before and after the surgery.

CT scans were taken of all the patients with isolated zygomatic arch fracture who were referred to Imam Reza Medical Center and department of maxillofacial surgery during 2019-20. The 50 mm needle was used for reduction with the new method.

This study was performed on 7 patients with isolated fractures of zygomatic bone. The mean age of patients was 33.85. 5.87 years. Significant reduction in pain was reported during 7 days after surgery, but the rate of edema (p = 0.539) and the amount of mouth opening after surgery did not show a significant difference.

In reviewing the above studies and comparing them with the present study, it was observed that in simple fractures, the surgical method of the present study was a very useful and uncomplicated method in patients. Despite open reduction methods, these methods have a lower scar rate, the duration of surgery is reduced, and this can lead to faster recovery of the patient.

 Pterion is a suture that is located in the lateral side of the skull in the depth of which there are middle meningeal vessels, the root of the lateral sulucus, the sinus cavernus, the bruca area and the insula cortex. In addition, it is a landmark for craniotomy and surgical approaches in tumors of the Willis ring or the frontal lobe for neurosurgeons. Due to the importance of pterion morphometry for neurologists, in the present study, morphometric indices of pterion and its types were studied in dry skulls.

This descriptive study was performed on 37 skulls with no deformity and pathologic problems in 2017-2018. The vertical distance of the pterion to the center of the zygomatic arch and its horizontal distance to the frontosigmatic suture were measured. Murphy division was used to investigate the types of pterions. Finally, the data were entered into SPSS software and analyzed with descriptive statistics and T-test.

A total of 37 skulls were examined. The mean vertical distance of the pterion to the center of the zygomatic arc was 1.99 ± 1.41 cm and the mean horizontal distance of the pterion to the frontosigmatic suture was 2.80 ± 0.76 cm. The frequency of the sphenoparital, frontotemporal, stellate, and epipetric types were 89.1%, 5.4%, 2.7%, and 2.7%, respectively. The statistical test did not show any significant difference between the distance between the pterion and the zygomatic arch (p = 0.16) on the left and right. There was a significant difference between the pterion and the fento-zygomatic suture on the left and right (p = 0.005).

The study of morphological features of the skull bone is useful for neurologists, forensic specialists, and anatomists. However, other studies with a higher sample size on the skull bone, as well as radiographs and CT scans in different parts of the country appear necessary.

A good radiograph with appropriate tube angulation can provide the dental practitioner with useful data، especially in multi-rooted teeth. The aim of this study was to compare three techniques of mesial tube shift، parallel and bisecting angle in preventing superimposition of zygomatic arch and the buccal and palatal roots of maxillary second molars on periapical radiographs.

In this cross-sectional research، 240 periapical radiographs were taken with the mesial tube shift، parallel and bisecting techniques، from 80 maxillary second molars (80 radiographs from each technique). Each radiograph was scored from 0 to 4، based on superimposition of zygomatic arch and the roots. Chi-squared test was used for data analysis (α = 0. 05).

The results of this research showed that in 73. 8% of cases the parallel technique had separated the root canals from the zygomatic arch; the separation was 57. 7% in the mesial tube shift technique but only 40% in the bisecting angle technique. There were statistically significant differences between the three techniques (p value < 0. 05).

Based on the results of this study، in the mesial tube shift technique separation of zygomatic arch from the roots of maxillary second molars was observed، but roots were superimposed on each other. However، in the parallel technique the roots and the zygomatic arch were separated without any superimposition. Mesial tube shift technique is the second choice in patients in which the parallel technique is not feasible; the bisecting angle technique is not recommended because of the superimposition of zygomatic arch on the roots.