CDA Essentials 2019 • Volume 6 • Issue 4

34 | 2019 | Issue 4 S upporting Y our P ractice Case 2: Patient presents with pain. This 40-year-old patient presents six months following extraction of the right-sided premolar/molar teeth in the mandible. There is pain on palpation that is dull and boring in nature. You have a panoramic radiograph. ( Figure 2 )  Navigation to a differential interpretation In the lower anterior, we have a reduction in the normal number of teeth. A periapi- cal radiograph ( Figure 1b ) shows that we also have one large tooth that appears to have taken the place of the mandibular right permanent cuspid and mandibular right permanent lateral incisor. They seem to share the same perio- dontium and pulpal space and the crown is far larger than the contralateral cuspid. • First fork in the road: normal or abnormal? There may be other abnormalities, but we will have another look at these at another appointment. Let’s address the chief complaint. It is not normal to have one large tooth replacing two teeth. It is normal to have four mandibular incisors; the radiographs show there are three normal mandibular incisors. • Second fork in the road: developmental or acquired? Are there any acquired conditions that push two teeth together to form one large tooth? No, so this is likely a developmental condition, but what are the possibilities? In order of likelihood: 1. Fusion of the mandibular right permanent lateral incisor and mandibular right permanent cuspid. 2. Prior extraction of the mandibular right permanent lateral incisor with concomitant partial germination of the mandibular right permanent cuspid. 3. Prior extraction of the mandibular right permanent lateral incisor with concomitant occurrence of a megadont mandibular right cuspid. The above is a differential diagnosis list, ordered by likelihood, of possible causes for the radiographic changes. In this list, the first possible cause is by far most likely due to the radiographic findings.  Fig. 1b Fig. 2