52
Članek prispel / Received
10. 12. 2020
Članek sprejet / Accepted
9. 10. 2021
Abstract
Purpose: To present the case of a 
patient with an inter-radicular super-
numerary tooth. 
Case report: A 45–year–old male 
patient presented with sepsis of odon-
togenic origin. Oral clinical investi-
gation and panoramic radiography 
revealed the presence of four avital 
teeth with inadequate root canal fil-
lings, including both maxillary first 
molars. The right one had periapical 
radiolucencies, indicating periapical 
periodontitis. The left one had an 
unusual radiopaque structure between 
the roots. Condensing osteitis, odon-
toma, and benign cementoblastoma 
were included in differential diagnosis; 
however, cone-beam computed tomo-
graphy (CBCT) showed a miniature 
supernumerary tooth located between 
the buccal roots of this tooth. Surgical 
removal of the inter-radicular tooth 
was not indicated, because there were 
no associated pathological changes. 
Izvleček
Namen: Namen prispevka je pred-
staviti primer medkoreninskega nad-
številnega zoba.
Poro~ilo o primeru: V primeru 
predstavljamo 45–letnega pacienta 
s sepso odontogenega izvora. Klinični 
pregled ustne votline in panoramski 
rentgenski posnetek sta pokazala štiri 
avitalne zobe z neustreznimi korenin-
skimi polnitvami, med katerimi sta 
bila oba prva zgornja stalna kočnika. 
Ob koreninah desnega so bile vidne 
periapikalne radiolucence, značilne 
za periapikalni parodontitis, med 
koreninami levega pa nenavadna 
radiolucentna struktura. V diferen-
cialni diagnozi so bili kondenzirajoči 
osteitis, odontom in benigni cement-
oblastom, računalniška tomografija s 
stožčastim snopom (RTSS) pa je po-
kazala, da gre za miniaturen nadšte-
vilni zob med bukalnima koreninama 
omenjenega zoba. Odstranitev med-
koreninskega zoba ni bila indicirana, 
Ključne besede: 
Zobne nepravilnosti, zobna 
nadštevilnost, dentalna radiologija, 
diferencialna diagnoza
Key words: 
Tooth abnormalities, hyperodontia, 
dental radiography, differential 
diagnosis
Opis redkega primera: Nadštevilen zob med 
koreninami prvega zgornjega stalnega kočnika 
Report of a rare case: supernumerary tooth between 
the roots of the permanent maxillary first molar
Avtor / Author Lucija Strmšek1, Iztok Štamfelj1, 2
Ustanova / Institute 1Univerza v Ljubljani, Medicinska fakulteta, Katedra za zobne bolezni in normalno morfologijo 
zobnega organa, Ljubljana, Slovenija; 2Univerzitetni klinični center Ljubljana, Center za 
zobne bolezni in endodontijo, Ljubljana, Slovenija;
1University of Ljubljana, Faculty of Medicine, Department of Dental Diseases and Normal 
Dental Morphology, Ljubljana, Slovenia; 2University Medical Centre Ljubljana, Department 
of Operative Dentistry and Endodontics, Ljubljana, Slovenia;
Poročilo o primeru / Case report: 
ACTA MEDICO-BIOTECHNICA
2021; 14 (1): 11–19
53
Poročilo o primeru / Case report: 
ACTA MEDICO-BIOTECHNICA
2021; 14 (1): 11–19
INTRODUCTION
Supernumerary teeth are those in excess of the nor-
mal number of 20 primary and 32 permanent teeth. 
The prevalence of supernumerary teeth in the per-
manent dentition varies from 0.5% to about 3.0% 
in different populations (1). The molar region in the 
maxilla is one of the most frequent regions for the 
occurrence of supernumerary teeth (2). Most of them 
are situated buccally to the molar row (paramolars) 
or distally to the third molar (fourth molars or dis-
tomolars). In this article, we describe a rare case of 
a supernumerary tooth located between the roots of 
the permanent maxillary first molar (inter-radicular 
tooth).
CASE PRESENTATION 
A 45-year-old male patient with sepsis was referred 
to the University Dental Clinic for evaluation and 
treatment. An oral focus of infection was suspected 
based on a positron emission tomography scan and 
isolation of a common oral pathogen, Aggregati-
bacter actinomycetemcomitans, from his blood. Pri-
or to referral, parenteral antibiotic treatment with 
ceftriaxone was initiated.
Oral clinical investigation and panoramic radiogra-
phy revealed no signs of periodontal disease; how-
ever, there were four avital teeth with inadequate 
root canal fillings: 25, 16, 26, and 46. Periapical 
radiography and cone-beam computed tomography 
(CBCT) showed periapical radiolucencies and thick-
ening of the antral mucosa associated with the roots 
of tooth 26. A diagnosis of asymptomatic periapical 
periodontitis was made. Periapical radiography also 
revealed an unusual radiolucent structure among the 
roots of tooth 16 (Figure 1). CBCT images clearly 
showed that this structure was a miniature supernu-
merary tooth (mesio-distal crown diameter 2.1 mm, 
bucco-palatal crown diameter 2.8 mm, tooth length 
7.7 mm) with a single root and a simple conically-
shaped crown (Figure 2). It looked like a small re-
placement tooth inside the bony septum separating 
the buccal roots (Figure 3). The root of the supernu-
merary tooth was in close proximity to the floor of 
the maxillary sinus (Figure 4). Surgical removal of 
ker ni bilo spremljajočih bolezenskih 
sprememb. V nadaljevanju je bil de-
sni prvi zgornji kočnik kot najverje-
tnejši izvor sistemske okužbe ekstrahi-
ran, preostali avitalni zobje pa so bili 
ponovno endodontsko zdravljeni.
Zaklju~ek: Medkoreninski nadšte-
vilen zob se pojavi redko, vendar je 
treba tudi to možnost upoštevati pri 
obravnavi radiopačne spremembe v 
predelu zgornjega stalnega kočnika. 
Njegova slika na običajnih rentgen-
skih posnetkih je lahko nejasna zaradi 
prekrivanja s sosednjimi koreninami. 
RTSS ima ključno vlogo pri postavi-
tvi pravilne diagnoze in ugotavljanju 
anatomskih odnosov. 
Subsequently, the right first molar was 
extracted as the most likely source of 
systemic infection. The remaining 
three avital teeth were endodontically 
re-treated.
Conclusion: An inter–radicular su-
pernumerary tooth is a rare occurren-
ce; however, it is important to take 
into account when evaluating a radi-
opacity associated with a permanent 
maxillary molar. Its image on conven-
tional radiographs may be unclear due 
to overlap with the neighbouring roots. 
CBCT plays a leading role in radiolo-
gic diagnosis and the establishment of 
anatomical relationships.
Naslov za dopisovanje /  
Correspondence
Doc. dr. Iztok Štamfelj, dr. dent. med., 
spec., Univerza v Ljubljani, Medicinska 
fakulteta, Katedra za zobne bolezni in 
normalno morfologijo zobnega organa, 
Hrvatski trg 6, 1000 Ljubljana, 
Slovenija
Telefon: +386 15224372
E–pošta: iztok.stamfelj@mf.uni-lj.si
54
Poročilo o primeru / Case report: 
ACTA MEDICO-BIOTECHNICA
2021; 14 (1): 11–19
this tooth was not indicated, because there were no 
associated pathological changes.
Tooth 26 was extracted. Endodontic re-treatment of 
the remaining three avital teeth was accomplished 
over the following seven months. Tooth 16 had a 
mesiobuccal root with three canals and distobuc-
cal and palatal roots with one canal each (Figure 5). 
DISCUSSION 
One of the unusual sites in the jaw where a super-
numerary tooth can develop is the inter-radicular 
septum of a maxillary molar. We have been able to 
find only three previous references to the presence of 
supernumerary teeth at this location. Schulze (3) de-
scribed a miniature supernumerary tooth, which was 
firmly lodged between the roots of an extracted max-
illary second molar. Huffman and Thatcher (4) and 
Jones (5) presented two patients, each with a slightly 
larger supernumerary tooth between the roots of the 
maxillary first and second molar, respectively.
An inter-radicular tooth tends to remain unerupted 
within the jaw, unless the adjacent maxillary molar is 
extracted. In the unlikely case that it remains in the 
jaw after extraction, it might erupt and replace the 
extracted molar, as if it were its true successor. An 
inter-radicular tooth may initiate external resorption 
in the furcal region of the roots (3, 4) and, although 
not documented, could cause follicular cyst forma-
tion. In our case, the patient was asymptomatic, 
there was no associated pathology, and the risk of 
developing external resorption in the future was con-
sidered negligible. Firstly, there was a considerable 
distance between the crown of the inter-radicular 
tooth and the furcal region of the maxillary first mo-
lar. Secondly, the root of the supernumerary tooth 
was fully formed, and no further tooth migration 
could be expected. The tooth was, therefore, left in 
place and kept under observation.
From a diagnostic viewpoint, it is important to dif-
ferentiate inter-radicular teeth from pathologic enti-
ties with a potentially similar radiographic appear-
ance but different prognosis and treatment, e.g., 
condensing osteitis, odontoma, and benign cement-
Figure 1. Periapical radiograph of the right perma-
nent maxillary first molar showing the presence of a 
radiopaque structure between the roots (arrow). 
Figure 3. Axial CBCT image of the right permanent 
maxillary first molar: MB – mesiobuccal root, DB – 
distobuccal root, P – palatal root, ST – root of the 
supernumerary tooth. 
Figure 2. Sagittal 
CBCT image re-
vealing the presence 
of a supernumer-
ary tooth between 
the buccal roots of 
the right perma-
nent maxillary first 
molar.
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Poročilo o primeru / Case report: 
ACTA MEDICO-BIOTECHNICA
2021; 14 (1): 11–19
oblastoma. In our case, the inter-radicular tooth was 
detected incidentally on conventional radiographs; 
however, the image was unclear due to its small size 
and superimposition on the roots of the adjacent 
maxillary molar. CBCT was helpful in making an ac-
curate diagnosis and determining the exact anatomi-
cal relationships. The additional finding of three 
canals in the mesiobuccal root of the first maxillary 
molar has also rarely been reported in the literature 
(6-8).
CONCLUSIONS
Clinicians should be aware that the inter-radicular 
septum of a permanent maxillary molar is a rare, 
yet possible location of a supernumerary tooth. The 
image of an inter-radicular supernumerary tooth on 
conventional radiographs may be unclear. CBCT is 
indicated to rule out pathologic entities with poten-
tially similar radiographic appearance but different 
prognosis and management.
Figure 
4. Cross-
sectional 
CBCT image 
of the right 
permanent 
maxillary 
first molar: 
P – palatal 
root, ST – 
supernumer-
ary tooth.
Figure 5. 
Postoperative 
radiograph 
of the right 
permanent 
maxillary 
first molar.
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