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Showing 3 results for Ramus
An investigation on the incidence of neurosensory disturbances of inferior alveolar nerve and condylardisplacement with Choung (IVSRO) osteotomy
Gh. Shirani , D. Kazemi ,
Volume 16, Issue 4 (1-2004)
Abstract
 Statement of Problem:The choung osteotomy (Intraoral Vertico- Sagittal Ramus Osteotomy) has developed since 1992 in the treatment of mandibular prognathism. In IVSRO, osteotomy plane is theoretically parallel to the original sagittal plane and thereby attempting to decrease the incidence of condylar dispacement. This osteotomy designed additionally to decrease neurosensory disturbances.
Purpose: The aim of this study was to evaluate the incidence of neurosensory deficit and condylar displacement with IVSRO and Sagittal Split Ramus Osteotomy (SSRO).
Materials and Methods: In this study, mandibular set back surgery was accomplished upon 7 patients by choung osteotomy. In addition to choung osteotomy, in 2 patients Lefort 1 osteomy was performed for maxillary protrusion and for 2 other patients, chain surgery was performed. Variables such as the neurosensory disturbances of inferior alveolar nerve and condylar displacement following choung osteotomy were investigated. All the patients were followed up one year after osteotomy. OPG, Lateral Cephalogram and Submentovertex radiographies were take pre and postoperatively for all patients.
Results: No statistically significant differences were found in condylar displacement (P>0.5). However, Mc Nemar analysis showed significant difference of neurosensory deficit between IVSRO and SSRO (P=0.001).
Conclusion: It is suggested that choung osteotomy is a safe procedure for mandibular surgery.
Assessment and comparison of proximal segment changes following mandibular set-back through bilateral sagittal split ramus osteotomy and intraoral verticosagittal ramus osteotomy
H. Mahmood Hashemi , P. Shokri ,
Volume 20, Issue 4 (1-2008)
Abstract

Background and Aim: Proximal segment movements following different methods of ramus osteotomy is one of the undesired consequences of orthognathic surgery. Theoretically, it seems that intraoral verticosagittal ramus osteotomy can minimize the movement of proximal segment. In this study, changes in intergonial distance and ramus flaring angles were evaluated and compared in transverse plane after mandibular set back by two osteotomy techniques.

Materials and Methods: In this randomized clinical trial 20 patients with mandibular prognathism without any asymmetry were selected and divided into two groups of 10 each.One group was treated by bilateral sagittal split ramus osteotomy and the other by intraoral verticosagittal ramus osteotomy technique. Intergonial width and inner ramal angle in transverse plane were measured on radiographs before and 1 and 12 weeks post surgery . Data were analyzed using covariance test with P<0.05 as the level of significance.

Results: Changes of intergonial distance and interramal angle in each group were significant after 1 and 12 weeks after surgery. No statistically significant difference was observed between the two studied groups.

Conclusion: According to the results of this study, there is no difference between bilateral sagittal split and intraoral verticosagittal ramus osteotomy techniques regarding mandibular width and ramus flaring changes.


Determination of the most appropriate stress distribution by Finite Element Analysis in fixation with resorbable screws after Blateral Sagittal Split Ramus Osteotomy surgery
F. Sarkarat, B. Bohluli, Sh. Ansari, H. Shahabi,
Volume 22, Issue 3 (12-2009)
Abstract

Background and Aim: Due to the complications associated with fixation by Titanium screws and plates in Bilateral Sagittal Split Ramus Osteotomy (BSSRO) surgery, the use of resorbable polymers has been increasingly recommended. Since there are not enough studies on this issue, this study aimed to assess the most appropriate stress distribution in fixation with resorbable screws after BSSRO surgery by Fnite Element Analysis (FEA).
Materials and Methods: This experimental study was performed on simulated human mandible using Ansys and Catia softwares. The osteotomy line was applied to the simulated model and experimental loads of 75, 135 and 600 N were respectively exerted according to the natural direction of occlusal force. The distribution pattern of stress was assessed and compared for fixation with one resorbable screw, two resorbable screws in vertical pattern, two resorbable screws in horizontal pattern, three resorbable screws in L pattern and three resorbable screws in inverted backward L pattern using Ansys software.
Results: Among the four simulated fixations, L pattern showed the highest primary stability. Two screws in vertical pattern were also associated with sufficient primary stability and less trauma and cost for patients. One screw did not provide enough stability under 600 N.
Conclusion: Polymer-based resorbable screws (polyglycolic acid and D, L polylactide acid) provided satisfactory primary stability in BSSRO surgery.


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