حمید مجتهدی

Condylar fractures are one of the most common fractures of the facial region. Currently there is no general agreement on surgical or nonsurgical treatment of condylar fractures. Facial nerve injury is the known as an unfavorable consequence of surgical treatments. The aim of this study was to assess the application of retromandibular transmasseteric antero-parotid approach in open reduction and internal fixation of subcondylar fractures.
Case Report: In a case series study from January 2014 to February 2015, 10 patients with subcondylar fractures underwent surgical treatment with retromandibular transmasseteric antero-parotid approach in Sina Educational/Treatment Center. Follow-ups were carried out at 1- and 2-week and 3- and 6-month postoperative intervals for the assessment of range of mouth opening, occlusion, facial nerve injury, salivary gland complications, infection and the amount of visible scar remaining. At 6-month follow-up of patients there was no case of facial nerve injury. All the patients exhibited normal range of motion of the mandible. Surgical scar was inconspicuous.
Retromandibular transmasseteric antero-parotid approach is appropriate and safe for open reduction and internal fixation of subcondylar fractures. This can be the method of choice for high and low subcondylar fractures and also coronoid and ramus fractures. Despite short surgical incision, it provides direct surgical access to the fracture area and the remaining surgical scar is indistinctive.

Nowadays Ni-Ti rotary files have many advantages and are totally accepted in endodontic treatment. Sterilization of Ni-Ti rotary files is essential due to their frequent clinical use. The aim of this study was to evaluate the surface characteristics of M-two rotary files before and after autoclaving with scanning electron microscopy (SEM).

Ten #25 new M-two Ni-Ti rotary files (VDW, Munich, Germany) with 0.06 taper were analyzed with scanning electron microscopy under two magnifications of ×200 and ×1000 before and after 1, 5 and 10 autoclave cycles in this experimental prospective study. Scanning electron microscopic images were inspected in relation to surface changes, including the presence of millings, debris and surface irregularities. Paired-sample t-test was used for data analysis with SPSS 22 (α=0.05).

Scanning electron microscopy measurements showed cavities, debris and surface irregularities on specimens of both file groups, in the as-received condition and after sterilization. Surface irregularities and corrosion increased significantly after 10 autoclave cycles (p value = 0.001).

The results showed that after multiple autoclave cycles, debris, holes and surface corrosion increased significantly. These surface imperfections were proportional to the number of autoclave cycles and single autoclave cycle seemed to have a less detrimental effect on rotary files. However, multiple autoclave cycles increased surface irregularities progressively. The results showed inherent Ni-Ti rotary file limitations in clinical usee and after multiple sterilization cycles.