CDA Essentials 2019 • Volume 6 • Issue 4

35 Issue 4 | 2019 | S upporting Y our P ractice  Observations • There is a diffuse radiopacity in the right mandible extending from about the location of the mandibular right third molar to the mandibular right central incisor. The bony cortices are within the range of normal at the superior and inferior aspects of the right mandible. • Although I see the tipping of the maxillary right third molar and associated periodontal bone loss, the generalized periodontal bone loss, the radiolucency at the apex of the maxillary left second premolar and the caries on this tooth (and the maxillary left third molar which is in an identical state), these observations are not the “main event.” • The maxillary left sinus may be somewhat more radiopaque than the one on the right (and compare the size of these sinuses to the case above). This opacity of the left sinus is something we may want to come back to later. • I counted the teeth in the maxilla and mandible and we are coming up short, probably due to extractions. • The rest of the teeth have some issues. There are restorations, including some large restorations; some chipped teeth; caries; malalignment etc. • If we next focus on the internal bony structures, nothing seems out of the ordinary, other than the apical lucencies in the maxillary areas previously pointed out. There is a bit of a patch of radiolucency in the region of the maxillary right first permanent molar right behind the maxillary right second premolar—within the range of normal—and some loss of the alveolar bone in the left maxilla— again within the range of normal—although I might want to check these areas clinically. • Focusing on the region of interest in the right mandible we have a poorly demarcated, not corticated, not encapsulated, mixed radiopacity/ radiolucency in the area formerly occupied by the second premolar, first permanent molar and second permanent molar. With regards to the internal structure, it is the same opacity as bone, not teeth, and if we compare right to left we can see that the bone of the right mandible is subtly but definitely more opaque, yet it retains its normal bony architecture. In short, the internal structure I see is bone—not tooth and not something else. • Considering the effect on adjacent structures, there are a few important points: 1. The inferior-alveolar neurovascular canal is very well-visualized and appears narrowed when compared to the one on the left. 2. I can still see some residua of the lamina dura, especially on the mandibular right first permanent molar. 3. There appears to be possible widening of the periodontal membrane space on the mandibular right first premolar apically (maybe even the lateral incisor and cuspid as well). 4. Of special note are four or five dense radiopacities surrounded by radiolucency, if you look closely apical to the first premolar but all above the mandibular canal. The more you look for them the more you will see. They are not normal. 5. The trabecular bone pattern is far less latticed and the struts are thickened.  Navigation to a differential interpretation • First fork in the road: normal or not normal? Not normal. • Second fork in the road: developmental or acquired? Acquired. From there we are going to rule out the following: 1. Cyst 2. Benign tumour 3. Trauma (we don’t count the trauma of extraction) 4. Fibro-osseous. Widened periodontal ligament spaces are not a feature of fibro-osseous lesions and neither are those punctate dense radiopacities. 5. Metabolic systemic conditions (which almost always affect the whole of the jaws). We are left with only two categories from which to pick: infection/inflammatory or malignant tumour. So let’s look at these two choices. Factors that favour infection as the probable cause: there is no overt osseous destruction, presence of those punctate radiopacities surrounded by lucency (sequestra), presence of a normal bony architecture that is more opaque than the contralateral side, really well-visualized mandibular right inferior alveolar canal, and perhaps a dentition that has been neglected and a history of extrac- tion. We will, of course, integrate these observations with the history and the clinical findings. Some might speculate that widening of the periodontal membrane spaces on the teeth adjacent to the region of interest are sine qua non of osteogenic sarcoma, and you are wise to suspect it. But widening of the periodontal membrane space can happen for a number of reasons. I view the presence of sequestra as the most important