CASE 18455 Published on 20.02.2024

Maxillary and mandibular late-developing supernumerary premolars (LDSP): A case report


Head & neck imaging

Case Type

Clinical Case


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


11 years, male

Area of Interest Head and neck ; Imaging Technique Cone beam CT, Conventional radiography
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).



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].


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
DOI: 10.35100/eurorad/case.18455
ISSN: 1563-4086