CASE 18455 Published on 20.02.2024
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Maxillary and mandibular late-developing supernumerary premolars (LDSP): A case report

Section

Head & neck imaging

Case Type

Clinical Case

Authors

Fiona Lourenco 1, Anish Patel 2

1 Oral and Maxillofacial Surgery and Orthodontic Department, Princess Royal Hospital, Shrewsbury and Telford Hospital Trust, Telford, United Kingdom

2 Orthodontic Department, Royal Shrewsbury Hospital, Shrewsbury and Telford Hospital Trust, Shrewsbury, United Kingdom

Connected authors
Patient

11 years, male

Categories
Area of Interest Head and neck ; Imaging Technique Cone beam CT, Conventional radiography
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Clinical History

An 11-year-old boy was referred to the Orthodontic Department with a Class II division I malocclusion, 6mm overjet and moderate crowding; he presented with three supernumerary teeth (ST) in the lower arch. The patient developed two additional ST in the upper and lower arch mid-treatment.

Imaging Findings

A diagnostic panoramic radiograph taken in September 2018 showed a developing dentition (Figure 1). Three unerupted supplemental ST were visible in the mandible; one between the 44 and 45 and another between the 45 and 46. There is also another ST in the lower left quadrant between the 34 and 35. Furthermore, a highly-positioned maxillary ST is evident close to the midline. Due to the proximity to the mental foramen bilaterally, elective premolar orthodontic extractions were limited to the maxillary arch. An up-to-date diagnostic OPG was taken post-COVID-19, demonstrating the presence of two additional ST (Figure 2). The first is visible in the lower left quadrant between 35 and 36, and the second is visible in the upper left quadrant between 23 and 25. Post-operative CBCT imaging demonstrated no signs of root resorption and confirmed the proximity of the ST to the mental nerve and inferior dental nerve (Figures 4 to 10).

Discussion

Background

Supernumerary teeth may be defined as any teeth or tooth substance over the usual configuration of twenty deciduous, and thirty-two permanent teeth [1]. It is vital to differentiate between permanent non-erupted dentition and unerupted supernumerary teeth. This is done by a combination of clinical and radiographic assessment while accounting for all expected 32 permanent teeth and checking for any discrepancies [2]. Frequently, patients are affected by a single supernumerary (76–86%), less by double supernumeraries (12–23%), and rarely by multiple supernumeraries (<1%) [3]. Supernumeraries commonly form from hyperactive of the dental lamina. Common complications associated with ST include cyst formation, crowding, delayed eruption or prevented eruption of permanent teeth, and resorption of adjacent structures [4,5]. 8% to 10% of ST are found in the premolar area [5].

Clinical Perspective

ST can be classified based on morphology, such as rudimental (conical (75%), tuberculate (12%) or odontome (6%)) or in a supplemental (7%) form. These are commonly present in the anterior maxilla (mesiodens) or posterior mandible (distomolar) [6]. They can also be found in the paramolar and parapremolar regions. We can further classify them based on their orientation (vertical, horizontal or inverted). Lastly, they can be classified based on their location (buccal, palatal, transverse) as well as if they are located within the alveolus (normotrophic) versus being located in the surrounding jaw, sinuses or nasal cavity (heterotrophic) [7]. A common problem is clinically unerupted supernumerary teeth; these are often incidentally detected on diagnostic radiographs.

Imaging Perspective

The full dentition is visible on panoramic radiographs; however, superimposition of the spine limits our ability to detect supernumeraries on the anterior maxilla. Hence, intra-oral radiographs in conjunction with an OPG enable improved detection of ST. Cone-beam computed tomography (CBCT) imaging may be indicated in assessing the exact location of ST and resorption of adjacent teeth [8].

Outcome

Management of ST varies from no therapeutic intervention to elective extraction. It is dependent on the impact of the ST on the adjacent structures. Due to the risk of paraesthesia, this patient opted for no treatment in the lower arch. Hence, CBCT imaging of the lower arch was delayed to a later stage. A post-operative OPG demonstrated further root formation of the aforementioned ST (Figure 3). Post-operative CBCT imaging, in this case, confirmed no evidence of root resorption (Figures 4 and 5). A GP referral was carried out for investigation for underlying genetic syndromes.

Take Home Message

More frequent monitoring of patients presenting with multiple supernumerary teeth must be considered. An OPG aids in the primary evaluation of ST and root resorption; CBCT imaging must be considered a vital adjunct to assess root resorption and proximity to adjacent vital structures such as the mental nerve or ID canal (Figures 6 to 10) [9]. An appropriate referral to the GP must be considered for common underlying genetic syndromes associated with ST, such as Gardner’s Syndrome, Cleidocranial Dysplasia or Familial Adenomatous Polyposis [4,10].

All patient data have been completely anonymised throughout the entire manuscript and related files.

Differential Diagnosis List
Supernumerary teeth
Late-developing supernumerary premolars
Gardner’s syndrome
Cleidocranial dysplasia
Final Diagnosis
Late-developing supernumerary premolars
Case information
URL: https://www.eurorad.org/case/18455
DOI: 10.35100/eurorad/case.18455
ISSN: 1563-4086
License

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

Figure 1

Diagnostic panoramic radiograph taken in September 2018 showing the developing dentition. Three unerupted ST (yellow arrows) were visible in the mandible; two in the lower right quadrant, one between 44 and 45 (labelled LR$1) and another between 45 and 46 (labelled LR$2). There is also another ST in the lower left quadrant between 34 and 35 (labelled LL$1). Furthermore, a highly-positioned maxillary ST (labelled UR$1) is evident close to the midline. Proximity to the mental foramen bilaterally (blue arrows)
Diagnostic panoramic radiograph taken in September 2018 showing the developing dentition. Three unerupted ST (yellow arrows) were visible in the mandible; two in the lower right quadrant, one between 44 and 45 (labelled LR$1) and another between 45 and 46 (labelled LR$2). There is also another ST in the lower left quadrant between 34 and 35 (labelled LL$1). Furthermore, a highly-positioned maxillary ST (labelled UR$1) is evident close to the midline. Proximity to the mental foramen bilaterally (blue arrows) is noted.
Figure 2

An up-to-date diagnostic OPG in March 2021 (post-pandemic) showed the presence of two additional ST. The first is visible in the lower left quadrant between the 35 and the 36 (LL$2), and the second is visible in the upper left maxillary segment between 23 and 25 (UL$1).
An up-to-date diagnostic OPG in March 2021 (post-pandemic) showed the presence of two additional ST. The first is visible in the lower left quadrant between the 35 and the 36 (LL$2), and the second is visible in the upper left maxillary segment between 23 and 25 (UL$1).
Figure 3

A post-operative OPG demonstrated further root formation of the aforementioned ST.
A post-operative OPG demonstrated further root formation of the aforementioned ST.
Figure 4

Sagittal slice of the small volume CBCT scan taken post-operatively confirming no root resorption of the adjacent teeth in the lower right quadrant.
Sagittal slice of the small volume CBCT scan taken post-operatively confirming no root resorption of the adjacent teeth in the lower right quadrant.
Figure 5

Sagittal slice of the small volume CBCT scan taken post-operatively confirming no root resorption of the adjacent teeth in th
Sagittal slice of the small volume CBCT scan taken post-operatively confirming no root resorption of the adjacent teeth in the lower left quadrant.
Figure 6

Coronal view of the post-operative CBCT scan demonstrating proximity of the LL$1 to the left mental foramen. The left mental foramen is buccal to LL$1.
Coronal view of the post-operative CBCT scan demonstrating proximity of the LL$1 to the left mental foramen. The left mental foramen is buccal to LL$1.
Figure 7

Coronal view of the post-operative CBCT scan demonstrating proximity of LL$1 to the left inferior dental (ID) canal. The left inferior dental canal makes direct contact with the open apex of LL$1 but not LL$2.
Coronal view of the post-operative CBCT scan demonstrating proximity of LL$1 to the left inferior dental (ID) canal. The left inferior dental canal makes direct contact with the open apex of LL$1 but not LL$2.
Figure 8

Coronal view of the post-operative CBCT scan demonstrating proximity LR$1 to the right mental foramen. The right mental foramen is buccal to LR$1.
Coronal view of the post-operative CBCT scan demonstrating proximity LR$1 to the right mental foramen. The right mental foramen is buccal to LR$1.
Figure 9

Coronal view of the post-operative CBCT scan demonstrating proximity of the LR$1 to the right ID canal. The right ID canal makes direct contact with the open apices of LR$1.
Coronal view of the post-operative CBCT scan demonstrating proximity of the LR$1 to the right ID canal. The right ID canal makes direct contact with the open apices of LR$1.
Figure 10

Coronal view of the post-operative CBCT scan demonstrating proximity of the LR$2 to the right ID canal. The right ID canal makes direct contact with the open apices of LR$2.
Coronal view of the post-operative CBCT scan demonstrating proximity of the LR$2 to the right ID canal. The right ID canal makes direct contact with the open apices of LR$2.