Well, this was an interesting case from 8 years ago. #18 and #19 were restored with CEREC inlay using the beloved Red Camera system and ProCAD (precursor to Empress CAD). #18b had caries on what would be it’s distal surface and we restored it with a glass ionomer.
Gemination is when one tooth bud attempts to generate two different teeth, as in this case. Whereas “fusion” occurs with two toothbuds running into each other during development. Fusion tends to occur on lower anterior teeth. Imaging with Galileos wasn’t completely necessary to diagnose this, but it sure helped the patient to understand why this could potentially cause trouble with the adjacent tooth. Even in early versions of Galileos, you could pick up detail like the resin cement layer of the inlays. It is exciting to watch the details of 3D scans become finer and finer. The periapical x-ray was taken with a phosphor plate system, ScanX.
We think he is quite lucky to have two lower second molars, but even more lucky to even have a first molar butted up against that!