ABSTRACT
Reconstruction of mandibular defects after trauma or tumor resection is one of the most challenging problems facing by maxillofacial surgeons. Few mandibular defects require not just a fixation of an implant, but the reconstruction of the entire mandible. The aim of this study was to design a mandibular prosthesis for a mandibular cancer patient and study its efficacy by stress-strain related mechanical property using finite element analysis [FEA]. One elderly male diagnosed as having mandibular cancer was included in the study. Multi-sliced computed tomography [CT] images of mandible were obtained under standard conditions. The images was analyzed by Materialise's Interactive Medical Image Control System [Mimics] software and Catia software. After applying suitable mechanical property of the bone, the biting and chewing forces were applied on the specific regions of the bone in the following cases: 1] normal mandible; 2] reconstructed mandible. The maximum value of von Mises stress, and the vector sum of displacement were measured. The specific softwares were evaluated through this study toward the needed steps for designing and analyzing the individual 3D models starting from the CT images. As expectedly, in reconstructed mandible, the measured maximum values of Von Mises stress [Pa] as well as the vector sum of the displacement were increased by 36% and 10% respectively, when compared to the normal mandible. It was shown that, the mechanical behaviour of the reconstructed mandible was close to the same of the normal bone. It is highly recommended to adopt such specialized softwares for images processing and for virtual surgery planning before the real operation, which would save the operation time and give more perspectives towards the optimal restorative model and the best fixation method
ABSTRACT
The aim of this study was to identify the configuration of the mandibular canal radiographically in the vertical direction on Digital Panoramic Radiographs to evaluate the relationship of the mandibular canal with the Status of the third mandibular Molar which will add important diagnostic radiographic signs specially before performing extraction of the mandibular 3[rd] molar. The sample consisted of 323 randomly chosen digital Panoramic radiographs for 160 males and 163 females with existing 3[rd] mandibular Molars. The cases were collected and evaluated at one big dental center in Damascus Through 12 months [year 2010], the sample was divided into 2 groups: the first group was for Patients under 40 years old, the second group consisted of Patients over 40 years old. The Radiographs were examined and evaluated with the SIDEXIS XG Programm. Two points were took as landmarks for the measurements: Point 1: the radiographic cross point of external and internal oblique lines and, Point 2: the inferior mandibular border. With the measurement choice in the Programm the distance between Point 1 and the superior border of the mandibular canal is measured, and also the extension of the past line between the inferior border of the canal and the inferior mandibular border in the same region. The ratio between the 2 measurements were calculated to define the location of the mandibular canal in the mandible in the vertical level, 3 classes were defined: Class 1: Ratio > or = 0.9 mm [the mandibular canal is positioned in the superior third of the mandible in the 3[rd] molar region] - Class 2: Ratio > or = 0.5 and < 0.9 mm [the canal is positioned in the middle third] - Class 3: Ratio > 0.1 and < or 0.5 mm [the canal is positioned in the lower third]. The biggest part of the cases [42.7%] had a class 2 localisation for the mandibular canal, class 1 [38%], class 3 [19.2%]. But males and females didn't show significant differences in relationship to the classification of mandibular canal. Class 1 had the biggest percentage [47.9%] of older patients [>40 years old]. In relationship with the radiographic interference of the 3[rd] molar with the canal, the class 1 had the highest percentage [47.9%] of radiographic interference. In relationship with the Impaction, the class 2 had the highest percentage [26.8%] of 3[rd] molars being impacted. The females had the bigger percentage [56.2%] [43.7% for males] of 3[rd] molars which are interfered with the mandibular canal radiographically. The Identification of the Mandibular canal path in the vertical Direction results in 3 types, and the classification wasn't sex or age related. The Classification shows a relationship with the mandibular 3[rd] molar localization relative to the canal especially in female patients. It is necessary to undertake more specific radiographic examinations [dental CT scan] before extracting mandibular 3[rd] molars in females in case a radiographic integration between the tooth and the canal is present
ABSTRACT
Clinical evaluation of the Neural complication after harvesting of mandibular ramus block grafts, by testing the mento-labial sensory disturbance and the vitality of teeth in the ipsilateral side. 13 patient [7 male-6 female] aged 19-47 years [mean 30.3] was included in this study where 15 ramus block grafts was harvested for alveolar ridge augmentation before implant placement, and the study was done in the oral and maxillofacial surgery department and implant clinics in Damascus university-dentistry school, all patients were followed up for 1 week-1 month-2 month- 4 month by testing the labio-mental sensory and the thermal pulp response, the statistical analysis was made by Cochran's Q test [p value<0.05]. The neuro-sensory complication rate was 6.7% and it was temporary with spontaneous resolve within 4 months, no alteration of the vitality of teeth was noted during the follow-up period. Ramus block graft are considered as a safe and suitable technique to augment the alveolar ridge, it is associated with fewer and temporary neural complication and does not alter the vitality of teeth when preformed as described in this study