The use of three different imaging methods for the localization of mandibular canal in placement of dental implant in the posterior region of mandible

The purpose of this study was to investigate the efficiency of panoramic radiography, conventional (cross-sectional) and computed tomography (CT) for detection of localization of the mandibular canal before placement of implant to posterior region of mandible. 6 dry edentulous adult human mandibles were used in this study. 12 slicing areas with gaps of 5 mm between each and which are extending from 1st premolar through 3rd molar teeth were determined for each mandible. Images of panoramic radiography, conventional and computed tomography (CT) were obtained from slice areas. Mi and M2 distances were measured on panoramic radiographs. Mi: The distance between alveolar crest and the side of inferior mandible M2: The distance between alveolar crest and superior border of the mandibular canal Cross-sectional images were obtained by using linear tomography option of OP 100 panoramic unit for conventional tomography. Reformatted images of 1 mm thick axial slices were obtained by DentaScan (General Electric Medical System, UK) software for CT images. Following distances were measured on conventional and computed tomography images besides Mi and M2 distances: M3: The distance of bucco-lingual width 5 mm under mandibular crest Mfc The distance of bucco-lingual width at circumference of mandibular canal The gold standard was determined by cutting mandibles from slicing areas with 1 mm thick carbon disc after obtaining all images. The measurements which were obtained from images were compared with actual mandible values. As a conclusion, CT was found as being the most efficient method in preoperative implant planning at posterior region of mandible even though it has disadvantages such as high radiation dose and its absence in most of the dental clinics. However, conventional cross-sectional images were also observed as being useful for obtaining information about bucco- lingual direction before surgery. This method gives information about bucco-lingual direction which is absent in panoramic radiography images and exposed radiation dose is relatively low when compared to CT. Conventional cross-sectional tomography is also available in most of the currently manufactured panoramic units just like the one that we used in this study. This provides an important advantage to clinicians for easy access. However, difficulties are faced in setting tomographic projection angles when obtaining cross-sectional images with these units and blurred images occurs because of the narrow tomographic angles. To minimize these disadvantages, both the staff who are taking images and the clinicians who are interpreting the images should be experienced. Better results may be obtained as an outcome.