Twin supernumerary teeth: A tale of two cases

Abstract

Multiple supernumerary teeth are one of the most common developmental anomalies in humans. They could be associated with prolonged retention of deciduous teeth, displacement or rotation of the adjacent teeth, crowding, aberrations in the root morphology (dilacerations), and failure in eruption or impaction of the succedaneous teeth. This article highlights 2 cases of non-syndromic mandibular twin supernumerary teeth in young female clients with a chief complaint of spacing between the teeth and over-retained deciduous teeth. A diligent clinical and radiographic monitoring is warranted considering the early innocuous effects and delayed adverse effects of this condition.

INTRODUCTION

Supernumerary teeth can be defined as any teeth or tooth substance in excess of the habitual conformation of 20 primary and 32 permanent teeth considered as vital constituents of the jaw. Its incidence may be single or multiple, unilateral or bilateral, erupted or impacted involving the maxilla, mandible or both. The clinical presentations are myriad, ranging from a simple odontome appearing as a conical or tuberculate tooth, to a supplemental tooth that can closely mimic a normal tooth (Figure 1).¹

There is no sex predilection in primary supernumerary teeth unlike in permanent supernumerary teeth, which are more prevalent among males. It has been linked to numerous genetic syndromes such as Ellis Van Creveld syndrome^{2, 3}, familial adenomatous polyposis⁴, trichorhinophalangeal syndrome^{2, 3}, Type I Rubinstein-Taybi syndrome³, Nance-Horan syndrome³, Opitz G/BBB syndrome⁴, occulofaciocardiodental syndrome⁴, Robinow syndrome⁴, and developmental disorders such as cleft lip and palate^2,3, cleidocranial dysplasia^2,3, and Gardner’s syndrome^2,3.

Potential complications associated with supernumeraries include local effects upon the developing occlusion (crowding, spacing, impaction, displacement or rotation), cystic formation, and resorption of adjacent teeth.⁵

The objective of this short communication is to highlight that unexplained spacing between teeth is a possible indication of the presence of supernumerary teeth or other pathologies of the jaw. Supernumerary teeth can be an early manifestation of an underlying genetic or hereditary disorder. It is rare to find multiple supernumeraries in individuals with no other associated disease or syndrome, although a few fragmented case reports have been published.^6,7,8

CASE 1

A 17-year-old female reported to the dental clinic for a routine dental check-up. She was concerned about the spacing between her teeth. She did not complain of any painful symptoms, and her medical and dental history were unremarkable. Clinical examination revealed spacing, multiple retained deciduous teeth, and missing permanent teeth. Her familial history was also non-contributory to spacing or prolonged retention of deciduous teeth. This initial exam prompted further investigation, which included a dental panoramic radiograph (DPR) (Figure 2) and an intraoral periapical radiograph (IOPA) (Figure 3), which confirmed the presence of twin supernumerary teeth and an impacted lateral incisor underneath the retained deciduous lateral incisor in the lower left region. The maxillary impacted canine would be favourably placed in the arch following extraction of the retained deciduous canine on the left side. The factors that would favour the early eruption of the maxillary canine into the arch in this case would be the presence of optimal space within the arch, favourable stage of root development, and minimal distance to traverse.⁹A diligent cephalocaudal general examination was done to look for abnormalities, growths, and swelling, considering a possible syndromic link, but the results were inconclusive.

Figure 1.

An algorithm illustrating the classification and syndromes associated with supernumerary teeth

The ugly duckling stage is a transient phenomenon in a mixed dentition known to cause spacing for the maxillary corner stones to erupt.¹⁰ However, in this case, considering the chronological age and spacing seen in the lower arch, the role of the ugly duckling stage was questionable. The surgeon then opted for extraction of the retained deciduous teeth (Figure 4), twin supernumerary teeth (Figure 5), and orthodontic traction of the impacted lateral incisor at a later date if required. Munns¹¹opined that the earlier the aberrant supernumerary tooth is removed, the better the prognosis.

Figure 2.

Orthopantomogram showing deciduous lateral incisor and twin supernumerary teeth

Figure 3.

Intraoral periapical film showing deciduous lateral incisor and twin supernumerary teeth

Figure 4.

Transalveolar extraction of supernumerary teeth

Figure 5.

Extracted mandibular deciduous canine and twin supernumerary teeth

CASE 2

An 11-year-old girl reported to the clinic for a routine dental check-up. She was concerned about her retained anterior deciduous teeth in the upper arch. She had no history of pain nor any relevant medical or dental history. Upon further questioning her mother disclosed the normal eruption pattern of the permanent lower central incisors (7 years) which was in accordance with her chronological age. Clinical examination revealed firmly retained deciduous maxillary central incisors, right deciduous lateral incisors, and highly placed angulated permanent left lateral incisors (Figure 6). Her familial history was also non-contributory to prolonged retention of deciduous teeth or any dental anomalies. Further investigations included a DPR that confirmed the presence of twin supernumerary teeth on the upper left lateral incisor region (Figure 7). The surgeon raised an envelope flap to extract the retained deciduous teeth (Figure 8) that had no signs of root resorption. Surgical exposure of the impacted tuberculate supernumerary teeth (Figure 9) was done with judicious bone removal under copious saline irrigation. Foster et al.¹²stated that tuberculate supernumerary teeth barely erupt and are often associated with delayed eruption of the incisors. This is in contrast to conical shaped roots that frequently erupt and do not hinder the eruption of the succedaneous tooth. Care was taken to avoid injury to the follicle of the unerupted superiorly placed permanent central incisors. Wound healing was satisfactory, one week postsurgery (Figure 10); a wait and watch policy was advised for the eruption of the permanent central incisors.

DISCUSSION

The first incidence of supernumerary teeth was reported between 23 and 79 AD.¹³The prevalence of supernumerary permanent teeth is approximately 1% to 3% with the order of frequency being the maxillary anterior teeth, the maxillary molars, and the maxillary/mandibular premolars. Only a meagre incidence of 0.01% in the mandibular anterior region has been reported in the literature.^14,15

Figure 6.

Retained deciduous central incisors with missing permanent central incisors and malposed maxillary lateral incisors

Figure 7.

Orthopantomogram confirming the presence of twin supernumerary teeth

Figure 8.

Extraction of retained deciduous central incisors

Figure 9.

Twin tuberculate supernumerary teeth

Figure 10.

One week postoperative satisfactory wound healing

The literature is replete with multiple theories hypothesized to trace the possible source of supernumerary teeth. Dichotomy of the tooth bud¹⁶, hyperactivity theory¹⁶, atavism theory^7,14, and hereditary and environmental factors have all been posited as a possible source of origin of supernumerary teeth.⁷

The evolution of the teeth and the jaws seems to involve a complex interplay between genetics and the environment. Aberrations in the stages of tooth development can cause a bizarre architecture of the tooth and its functions. Current knowledge concerning tooth development is based on mouse models, which has helped to understand the molecular wizardry as to how the population of the tooth is controlled at the molecular level.¹⁶The untimely regulation of Sonic hedgehog (Shh) activity may play a vital role in the development of supernumerary teeth.¹⁷The other molecular signaling pathways, such as components of fibroblast growth factor (FGF), wingless (Wnt), tumour necrosis factor (TNF) and bone morphogenetic protein (BMP) families, which are involved in the normal development of the tooth germ, can give rise to additional teeth if inappropriately regulated.^18,19,20

These cases offer a rare presentation of non-syndromic twin supernumerary teeth and highlight their possible clinical ramifications, which include displacement, rotation, ectopic eruption of the adjacent teeth, resorption of the adjacent teeth, and occurrence of primordial cysts.¹⁶These ramifications did not arise in either of the 2 cases, other than the subtle spacing, thanks to the early diagnosis. A periodic clinical and radiographic examination is important in an asymptomatic supernumerary tooth with red flags such as spacing, painless expansion, and an incongruency between the chronological and dental age. ,Supernumerary teeth are often removed surgically in over-retained deciduous teeth when they hinder the path of eruption of the permanent teeth. In cases where the supernumerary teeth do not cause alterations in the eruption, position or integrity of the permanent dentition, a conservative approach is preferred. ²¹

The tuberculate type of supernumerary teeth have more than one cusp or tubercle (barrel shaped). There are 4 morphologically diverse types of supernumerary teeth in the permanent dentition: conical, tuberculate, supplemental, and odontome.^1,22The conical is a miniature peg-shaped tooth located between the maxillary central incisors as a mesiodens.^8,23,24Tuberculate supernumerary teeth are bulky and barrel shaped with several tubercles or cusps, and their roots are incomplete or abnormally formed. They are frequently paired and rarely erupt into the oral cavity. A sequelae to this is either delayed eruption of the permanent incisors or displacement.^{12, ,25} Both of these findings were seen in the second case. Because a single supernumerary tooth has been reported to be the most common, the presence of twin supernumerary teeth in the maxilla and mandible with innocuous clinical presentation warrants the reporting of these cases.²⁶

Tuberculate supernumerary teeth are known to remain indolent for years before complications arise. These include cessation of tooth eruption, delayed eruption of permanent teeth, ectopic eruption, diastema, displacement, rotation of adjacent teeth, and crowding. The other less common manifestations include periodontitis, dilacerations, dentigerous cyst formation, root resorption of adjacent teeth, occlusive disturbance, and unaesthetic appearance.^23,27

CONCLUSION

Supernumerary teeth represent one of the most common developmental anomalies in humans, with a clear genetic component.³ However, little information exists on its molecular wizardry and biogenesis. Dental hygienists need to be vigilant while they examine their clients with spacing or a mismatch between the chronological age and dental age. Treatment of each case must be individually tailored, taking into account possible sequelae like malocclusion, retention of permanent teeth or tendency for cyst formation.

CONFLICT OF INTEREST

The authors have declared no conflicts of interest.