Omer RS, Anthonappa RP, King NM. Determination of the optimum time for surgical removal of unerupted anterior supernumerary teeth. Pediatr Dent. 2010; 32:14-20
Ata-Ali F, Ata-Ali J, Penarrocha-Oltra D, Penarrocha-Diago M. Prevalence, etiology, diagnosis, treatment and complications of supernumerary teeth. J Clin Exp Dent. 2014; 6:e414-418 https://doi.org/10.4317/jced.51499
Arandi NZ, Abu-Ali A, Mustafa S. Supernumerary teeth: a retrospective cross-sectional study from Palestine. Pesqui Bras Odontopediatria Clín Integr. 2020; 20 https://doi.org/10.1590/pboci.2020.029
Primosch RE. Anterior supernumerary teeth – assessment and surgical intervention in children. Pediatr Dent. 1981; 3:204-215
Anthonappa RP, Omer RS, King NM. Characteristics of 283 supernumerary teeth in southern Chinese children. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2008; 105:48-54 https://doi.org/10.1016/j.tripleo.2008.01.035
Garvey MT, Barry HJ, Blake M. Supernumerary teeth--an overview of classification, diagnosis and management. J Can Dent Assoc. 1999; 65:612-616
Mahabob MN, Anbuselvan GJ, Kumar BS Prevalence rate of supernumerary teeth among non-syndromic South Indian population: an analysis. J Pharm Bioallied Sci. 2012; 4:S373-375 https://doi.org/10.4103/0975-7406.100279
Kumar DK, Gopal KS. An epidemiological study on supernumerary teeth: a survey on 5,000 people. J Clin Diagn Res. 2013; 7:1504-1507 https://doi.org/10.7860/JCDR/2013/4373.3174
Anthonappa RP, King NM, Rabie AB. Aetiology of supernumerary teeth: a literature review. Eur Arch Paediatr Dent. 2013; 14:279-288 https://doi.org/10.1007/s40368-013-0082-z
Kawashima A, Nomura Y, Aoyagi Y, Asada YJPDJ. Heredity may be one of the etiologies of supernumerary teeth. 2006; 16:115-117
Fleming PS, Xavier GM, DiBiase AT, Cobourne MT. Revisiting the supernumerary: the epidemiological and molecular basis of extra teeth. Br Dent J. 2010; 208:25-30 https://doi.org/10.1038/sj.bdj.2009.1177
Melamed Y, Barkai G, Frydman M. Multiple supernumerary teeth (MSNT) and Ehlers-Danlos syndrome (EDS): a case report. J Oral Pathol Med. 1994; 23:88-91 https://doi.org/10.1111/j.1600-0714.1994.tb00263.x
Groden J, Thliveris A, Samowitz W Identification and characterization of the familial adenomatous polyposis coli gene. Cell. 1991; 66:589-600 https://doi.org/10.1016/0092-8674(81)90021-0
Mallineni SK, Jayaraman J, Yiu CK, King NM. Concomitant occurrence of hypohyperdontia in a patient with Marfan syndrome: a review of the literature and report of a case. J Investig Clin Dent. 2012; 3:253-257 https://doi.org/10.1111/j.2041-1626.2012.00148.x
Mallineni SK. Supernumerary teeth: review of the literature with recent updates. Conference Papers in Science. 2014; 2014 https://doi.org/10.1155/2014/764050
Proff P, Fanghanel J, Allegrini S Problems of supernumerary teeth, hyperdontia or dentes supernumerarii. Ann Anat. 2006; 188:163-169 https://doi.org/10.1016/j.aanat.2005.10.005
Russell KA, Folwarczna MA. Mesiodens – diagnosis and management of a common supernumerary tooth. J Can Dent Assoc. 2003; 69:362-366
Oliver G, Hamilton S, Read N, Atack N. The continued development of multiple supernumerary teeth: do they influence orthodontic treatment?. Orthodontic Update. 2021; 14:125-133 https://doi.org/10.12968/ortu.2021.14.3.125
Early removal of supernumeraries to close a midline diastema: a case report Laura Brooks Kelly Smorthit Jonathan Sandler Dental Update 2024 16:1, 707-709.
A midline diastema is a part of normal dental development, which, in the mixed dentition, is termed the ‘ugly duckling’ stage. Supernumerary teeth, however, can also be a cause, with the most common type being a mesiodens. Supernumeraries can cause other complications including delayed or failure of eruption of a permanent tooth, displacement of crowns, crowding, root resorption and cyst formation. Treatment options for supernumeraries include immediate or delayed removal or active monitoring. This article advocates for early diagnosis and treatment to reduce the need for future complex treatment.
CPD/Clinical Relevance: This case emphasizes the importance for clinicians to accurately and carefully diagnose the cause of a midline diastema and the presence of supernumerary teeth early in development. Prompt orthodontic referral can reduce the need for later complex surgical and orthodontic treatment.
Article
A supernumerary tooth (ST) is ‘any tooth or odontogenic structure that is formed from tooth germ in excess of usual number for any given region of the dental arch.’1 They present as single or multiple teeth, unilaterally or bilaterally and can occur in both the maxilla and mandible.2 They are more prevalent in the maxilla by up to 10 times, and are more common in the premaxillary region.3,4 The most common type of ST is the mesiodens5 and they are more prevalent among men than women in a ratio of between 2:1 to 3.25:1.4,6 Prevalence in the deciduous dentition is 0.3–0.8% and 1–3.5% in the permanent dentition.4,7,8,9
The aetiology of ST is still unclear; however, several theories have been proposed:
Atavism: is a type of long distance heredity and so, ST are a reversion to an ancestral human dentition that contained a greater number of teeth.10
Dichotomy: division of a tooth bud into two teeth of equal size or one normal and one dysmorphic tooth.2
Dental lamina hyperactivity: there is a localized, independent and conditional hyperactivity of remnant epithelial cells of the dental lamina, which is the most widely accepted reason.10 A rudimentary form (teeth of abnormal shape and smaller size) develop from the proliferation of epithelial remnants of the dental lamina and a supplemental form (teeth of normal shape and size) develop from the lingual extension of an additional tooth bud.5
Genetic factors: there are multiple reports to support the theory of a familial tendency to ST with autosomal dominant inheritance and a sex-linked pattern being proposed.11 Mouse models are being used to investigate the role of different genes in tooth development, including the regulation of the number and development of supernumeraries.12
Associated syndromes: ST are associated with syndromes such as cleidocranial dysplasia,13 Ehlers–Danlos syndrome, 14 Gardner's syndrome15 and Marfan syndrome.16
Location: mesiodens (between the two central incisors), paramolar (palatal or labial to a molar), distomolar (distally to the third molar) and parapremolar (palatal or labial to a premolar).
Position: buccal, palatal, transverse.
Orientation: vertical or normal, horizontal, inverted.17
The presence of a ST can cause various complications including:
Midline diastemas: often caused by an unerupted or erupted mesiodens.
Delayed or failure of eruption of a permanent tooth: often affects the premaxillary region with a tuberculate ST.
Displacement of the crowns of adjacent teeth: mild rotation to severe displacement.
Crowding: often caused by an erupted or unerupted supplemental ST.
Root resorption: sometimes loss of vitality of the adjacent tooth occurs.
Cyst formation: dentigerous cysts are the common type.1,7,18
Thorough clinical and radiographic examination is required to correctly identify and locate an ST and any of the complications above should alert the clinician that an ST may be present. A vertical or horizontal parallax technique using a combination of long cone peri-apicals, or an upper standard occlusal and a dental panoramic radiograph is required. Where an ST is to be surgically removed, and its location is in the region of important anatomical structures, a small FOV CBCT is justified.19 Treatment options for ST include immediate or delayed removal or, if no complications are present, regular monitoring with no intervention.1,20
A diastema is a space greater than 0.5 mm between the proximal surfaces of two adjacent central incisors.21 A midline diastema in the mixed dentition is often seen, and is labelled as the ‘ugly duckling’ stage and is part of normal dental development. Patients aged 6–8 years have the highest prevalence of maxillary midline diastemas, which usually reduces with age following full eruption of lateral incisors and canines.21
The following case illustrates the benefits of early referral for an orthodontic assessment of a midline diastema due to ST, and early interceptive treatment.
Case report
A 6-year old female patient was referred by the Community Dental Service to Chesterfield Royal Hospital orthodontic department for assessment of two asymptomatic upper midline supernumerary teeth, which were causing a midline diastema. Medically the patient was fit and well, took no regular medications and had no known allergies.
Examination revealed a Class 1 skeletal pattern with an early mixed dentition. Two upper midline supernumeraries were present, preventing the two central incisors coming together. The upper right ST was fully erupted and the upper left ST partially erupted and slightly palatally positioned (Figure 1). The upper central incisors were partially erupted, rotated and positioned lateral to the ST. An OPG and a peri-apical radiograph were taken by the referring clinician (Figure 2).
Figure 1.
(a, b) A 6-year-old female patient showing two midline supernumeraries causing an extremely large midline diastema and rotated upper central incisors.Figure 2.
(a) OPG and (b) peri-apical radiograph showing the two supernumerary teeth at age 6 years.
The treatment plan involved extraction of the two ST under general anaesthetic with the hope of spontaneous improvement in the position of the two central incisors. Surgery was performed when the patient was 7.5 years old. Figure 3 shows spontaneous reduction of the midline diastema 6 months after surgery, and Figure 4 illustrates complete closure of the midline diastema at 10 years old. The patient continues to be reviewed periodically to ensure correct eruption of the upper canine teeth.
Figure 3.
(a, b) Significant closure of the midline diastema 6 months post-surgery.Figure 4.
(a, b) Complete closure of the midline diastema at 10 years old.
Discussion
A midline diastema can be caused by normal dental development, a missing tooth, a peg-shaped lateral, proclination of the upper labial segment, a prominent midline frenum or a midline supernumerary tooth, which occurred in the case described above.22 Ethnic differences also exist, with the prevalence of maxillary midline diastemas greater in those of African origin than in those of European or East Asian origin.23
Indications for removal of ST include when eruption of the central incisor has been delayed or displacement has occurred. Other indications include associated pathology, spontaneous eruption of the ST, if active orthodontic alignment would result in close proximity to the ST, or if the ST compromised alveolar bone grafting in cleft lip and palate patients.7
In the literature, optimal timing for surgical intervention remains controversial, with some clinicians advocating immediate removal, while others favour a delayed approached. The advantages of immediate removal following early diagnosis are avoidance of: space loss, midline shifts, cyst formation and root resorption, failure of correction of the displaced teeth using the spontaneous eruptive forces of adjacent teeth, and preventing extensive future surgical and orthodontic treatment.24 The disadvantages of early removal include the possible risk of loss of vitality and root malformations of adjacent teeth, and the inability of a young child to cope with a surgical procedure.5 Because of these concerns, some clinicians recommend delayed intervention until root formation of adjacent teeth is completed, around 10 years of age for an upper central incisor.5 However, Omer et al state that the optimal age for removal of a maxillary ST is 6–7 years of age after which more complications are expected.1 This can be demonstrated by the case described in Figure 5 where a delayed approach has resulted in a rotated UR1 due to the presence of an unerupted mesiodens.
Figure 5.
(a–c) An unerupted mesiodens causing rotation of the UR1.
Occasionally ST are asymptomatic and may be detected as a chance finding during radiographic examination. Such teeth can be actively monitored if there is no associated pathology, satisfactory eruption of related teeth, no orthodontic treatment planned and removal could risk loss of vitality of the adjacent teeth.7 This decision was taken in the case shown Figure 6. There are no radiographic guidelines related to the frequency of monitoring, but the authors suggest every 2 years would be reasonable. During active monitoring, clinicians need to be aware of the risk of development of late-forming ST, especially in the lower premolar region and which can occur after a patient has previously developed anterior maxillary ST.25
Figure 6.
(a) OPG showing horizontally impacted supplemental supernumerary extending from UR1 to UR3. (b) CBCT axial view showing no pathology related to the supernumerary.
Conclusion
This case demonstrates the importance for clinicians to accurately and carefully diagnose the cause of a midline diastema, which in this scenario was because of ST, early in development. Timely orthodontic referral allowed for optimal treatment, reducing the need for later more complex surgery and orthodontics.
