دراسة شعاعية راجعة لتحديد مسار قناة الفك السفلي وعلاقتها مع الرحى الثالثة السفلية في دمشق

Background& Objective: 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 3rd molar . Materials & Methods: The sample consisted of 323 randomly chosen digital Panoramic radiographs for 160 males and 163 females with existing 3rd 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 3rd 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) Results: 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 3rd 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 3rd molars being impacted . The females had the bigger percentage (56.2%) (43.7% for males) of 3rd molars which are interfered with the mandibular canal radiographically Conclusion: 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 3rd 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 .