PMC5435902_01
Frontal view of the patient class III occlusion.
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Class III molar occlusion was seen with 11 palatally displaced (Figure 1).
OPT of the patient with supernumerary dental group.
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Examination of the OPT (Figure 2) revealed the presence of numerous radiopaque areas in the left incisor region and the consequent difficulty in the eruption of 21 placed over the supernumerary dental group.
(a) CBCT of the patient showing 3 deciduous teeth (61 in red circle, 62 in yellow circle, and 63 in green circle) and 2 supernumerary teeth (blue and violet circles). (b) CBCT of the patient showing displacement of permanent teeth 21 and 22.
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The analysis showed a group of 2 supernumerary teeth placed palatally to 61 and 62 with an indefinite shape (Figure 3(a)) and element 21 being displaced apically. Tooth 22 was placed more apically than the contralateral one, palatally and distally in contact with the root of 63 (Figure 3(b)). Four supernumerary teeth, two visualized in OPT and CBCT (A:blue circle and B:violet circle as reported in Figures 3(a) and 4(d)) and two discovered upon surgical removal (C and D:black circle in Figure 4(d)), were harvested and processed according to a calcified tissue protocol.
(a) Intraoral view after soft tissue elevation. (b) Intrasurgical view after the extraction of deciduous teeth and the exposure of the supernumeraries. (c) The alveolar site free from supernumerary teeth. (d) Deciduous and supernumerary teeth after the extraction. They are indicated with the same colours used in Figure 3(a). Third and fourth supernumeraries can be seen.
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As expected two malformed supernumerary elements were found, but the accurate curettage of the bone revealed a third and fourth abortive elements formed apically and distally to the distal supernumerary tooth (Figures 4(a) and 4(b)). They appeared as small dental germ-like formations with an irregular shape and resulting softer than normal teeth upon compression (Figures 4(c) and 4(d)). Four supernumerary teeth, two visualized in OPT and CBCT (A:blue circle and B:violet circle as reported in Figures 3(a) and 4(d)) and two discovered upon surgical removal (C and D:black circle in Figure 4(d)), were harvested and processed according to a calcified tissue protocol.
The ground sections of tooth A (a-b) and tooth B (c-d) under light microscope (a, c) and polarized microscope (b, d). The sections are not stained and polarization highlights mineralized tissue. Enamel appears more birefringent than dentine due to its higher level of calcification.
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Morphological analysis suggests that tooth A (indicated in Figures 5(a) and 5(b)) presents a morphology similar to a canine tooth, while tooth B (indicated in Figures 5(c) and 5(d)) resembles a premolar tooth.
The ground sections of the two "ghost" teeth C (a-b) and D (c-d) under light microscope (a, c) and polarized microscope (b, d). The sections were stained with Toluidine Blue and Pyronin Y. Polarization highlighted a limited area containing mineralized tissue. The papilla in (b) did not present areas of calcified tissue, thus resulting as not birefringent.
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The tooth C showed a structure similar to a developing dental papilla characterized by dental pulp mesenchymal-like tissue (Figures 6(a) and 6(b)). Furthermore, at one point on the papilla border, indicated with a red arrow (Figure 6(a)), a small area of mineralized tissue similar to dentine was observed. Furthermore, the core was populated by many cells of mesenchymal origin similar to cells described in relation to tooth C (Figure 6(a)).
Details of the "ghost" teeth C and D under light microscope (a-c): (a) mesenchymal-like tissue; (b) dentine fragment; (c) odontoblast-like cells (red arrow) that appear to be in a phase of matrix deposition around calcified granules (yellow arrow). Toluidine Blue and Pyronin Y staining, total magnification 400x.
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It was possible to distinguish a portion characterized by mineralized islands located mainly in peripheral area (Figures 7(a) and 7(b)) and mesenchymal-derived tissue similar to dental pulp core (Figure 7(c)).  Figure 7(a) shows one of the irregular dentine fragments, clearly identifiable by the presence of dentinal tubuli. The cells seemed to be in the process of creating typical fence/palisade structure and ready to deposit dentine (Figure 7(b), red arrow).