Authors: Dr. Smita Singh, Dr. Vinay Kumar.
Darshan Dental College & Hospital, Udaipur, Rajasthan, India



Abstract:
Supernumerary teeth are the teeth in excess of the normal number, varied in form and location and occur in both primary and permanent dentition. Detection of supernumerary teeth is best achieved by thorough clinical and radiographic examination. Supernumerary premolars have been reported to occur in 0.29% of the general population and to represent about 9.1% of all supernumerary teeth. Most reported cases of supernumerary maxillary premolars were of ectopic varieties, erupting buccal or lingual to the natural dentition.

The remarkable features of these cases are that the unilateral and bilateral supernumerary premolars were transposed between the first and second permanent maxillary molars, properly aligned in the arch and not interfering with occlusion. Unilateral supernumerary tooth was treated successfully with endodontic treatment.

This paper report rare cases of the bilateral and unilateral transposed supernumerary premolar distal to the maxillary right first molar. The unilateral supernumerary tooth was successfully treated endodontically

Introduction:
A supernumerary tooth is one that is additional to the normal series and can be found in almost any region of the dental arch¹.The prevalence of this abnormality varies between 1.5% and 3.5% in the permanent dentition in comparison with 0.3 to 0.6% in the deciduous dentition. Supernumerary teeth are more frequent in males than in females in a proportion of 2:1² Supernumerary teeth may occur singly, bilaterally or even in multiples. Supernumerary teeth are situated especially in the premaxillary region 90%, with 93% of them in central incisor region, with 25% of those located in the midline. Of the remaining 10%, about 4% and 1.5% are located in the mandibular premolar and maxillary canine regions, respectively.³

Sometimes supernumerary teeth are found to be associated with some systemic diseases or syndromes like Gardner’s syndrome, cleidocranial dysplasia and in patients with cleft lip and palate, however, literature has evidently reported cases of non-syndromic solitary or multiple supernumerary teeth.⁴

Supernumerary teeth are classified according to morphology and location.  In the primary dentition, morphology is usually normal or conical. There is a greater variety of forms presenting in the permanent dentition.1 According to World Health Organization Classification, supernumerary teeth are: supernumerary K01.18, supernumerary - incisor KOO.10, canine KOO.10, - premolar KOO.ll, - molar K00.12,  - supplementary KOO.l, - transposition K07.34. ⁵

Case report:
Case 1 : A 51 years old man patient reported to the Department of Conservative and Endodontics, with the chief complaint of pain in the upper right back tooth. On intra-oral examination an extra tooth was found between the maxillary right first and second molar. This extra tooth had crown with two cusps and was smaller in size compared to the adjacent normal molars resembling like a premolar crown (Figure -1). Clinical examination revealed a distal carious lesion in relation to supernumerary tooth with pain and tenderness. On soft tissue examination there was inflammation in the interdental papilla between the first and second molars around the supernumerary tooth. This unilateral supernumerary tooth was well placed within the arch, neither palatally nor buccally as seen in cases of paramolars. (Figure 1 , 2)

Figure 1	Figure 2	Figure 3	Figure 4

The preoperative radiograph demonstrated a distal radiolucency approaching the pulp space and widening of periodontal ligament space. The root was tubular in shape with a single root canal. The length of the root was comparatively shorter than the length of adjacent premolars and molars. ( Figure 3)

Patient’s medical and family history was not relevant and there were no signs of any systemic disease or syndromic features. Patient was advised to get the root canal treatment done.

Figure 5	Figure 6	Figure 7	Figure 8

Following local anesthesia, an endodontic access cavity was prepared. Examination of pulp chamber floor revealed one distinct root canal orifice. Cleaning and shaping of canal was done, and the canal was dried with absorbent points. The obturation was done by cold lateral compaction of gutta-percha. After a gap of 1 month tooth was assessed clinically and was found that there was no pain, tenderness. ( Figure 4 ) Tooth was then restored with composite ( Figure 5)  followed by full crown.

Case 2 : A 32 year old male patient was referred to the department for class 2 caries with tooth situated posterior to right maxillary first molar. On intra oral examination, extra teeth were found between the 1st and 2nd maxillary molars on both side of the arch. These extra teeth had crowns with two cusps and resembling a premolar crown ( Figure 6 , 7 ). Radiographic examination revealed, the length of the root was comparable to the adjacent premolars and molars ( Figure 8 ) . Patient’s medical and family history was not relevant and there were no signs of any systemic disease or syndromic features.  Clinical examination revealed a mesial carious lesion in relation to right supernumerary tooth. On soft tissue examination there was inflammation in the interdental papilla between the first molars and the supernumerary tooth. The right maxillary supernumerary tooth was then restored with composite restoration.

Discussion:
Supernumerary premolars, especially in the maxillas, are unusual condition.  In these cases, the supernumerary transposed premolar teeth were properly aligned in the arch and were not interfering with occlusion.

On occasion, the normal or supernumerary teeth may erupt into an inappropriate position. This pattern of abnormal eruption is called dental transposition. One needs to exercise caution when diagnosing transpositions to avoid confusing them with mere ectopic eruptions. In transposition, the teeth exchange places, thereby reversing their sequence in the mouth. Ectopic eruption is a broad category referring to any abnormal or aberrant eruptive position taken by a tooth. Transposition, therefore, must be considered a subdivision of ectopic eruption. All transpositions are examples of ectopic eruption, but few ectopic eruptions are transpositions.^6,7

Supplemental premolars transposed and erupted into occlusion are not frequently reported in the literature.^8,9,10,11,12 Most reported cases of supernumerary maxillary premolars were of ectopic varieties, erupting buccal or lingual to the natural dentition.

Supernumerary premolars are more likely to develop in the mandible than in the maxilla¹³ They have been reported to occur in 0.29% of the general population and to represent about 9.1% of all supernumerary teeth.¹⁴

Barnett reported a case with supernumerary premolars between the first and second molars which was erupted buccally in the maxilla and lingually in the mandible. Lin17 reported cases with supplemental teeth distal to the maxillary first permanent molars which were displaced ducally and not in occlusion. ¹⁵

Vijayavergia et al reported a case of two bilaterally functioning supernumerary transposed premolars located distal to the permanent maxillary first molars in normal occlusion.⁸ Ngeow WC, Means and Tabeling reported a case of a unilateral transposed supernumerary premolar in occlusion.^11,12

The exact etiology of the supernumerary teeth has not yet completely understood. Several theories have been suggested for their occurrence, such as the phylogenetic theory, the dichotomy theory, and occurrence due to hyperactive dental lamina16 and due to a combination of genetic and environmental factors.¹⁷

Most teeth erupted in their expected position in the dental arch. On rare occasions however, a tooth may be reversed in its site of eruption (such as a canine between two premolars). The etiology of transposition remains speculative. Various theories have been proposed to explain the phenomenon, including transposition of dental anlage during development, migration of a tooth during eruption, heredity and trauma.¹⁸

A complete radiographic survey of the entire oral cavity is essential to identify the presence of all impacted supernumerary teeth because the ratio of impacted to erupted supernumerary teeth ranges from 3 to 1.¹⁹ However, radiographs alone are not adequate for the definitive diagnosis. Their interpretation should always be conducted in conjunction with clinical findings.    

Occasionally, supernumerary teeth may lead to complications such as deep caries in the adjacent teeth, which may require restoration or endodontic therapy of the adjacent teeth as well. Treatment depends on the type and location of the supernumerary teeth and on its potential effect on adjacent hard and soft tissue structures. Supernumerary teeth can be managed either by removal or endodontic therapy or by maintaining them in the arch are frequent observation.

When supernumerary teeth and transposed teeth are erupted but not in alignment, they can cause displacement of the adjacent teeth with crowding enhancing various types of malocclusion. The adjacent teeth may be tipped, rotated or in infra occlusion. This may cause trauma to the surrounding structures. Generally, they may also cause difficulty in function like disturbing speech and chewing. In these cases of transposed supernumerary premolars the patient were unaware about the supernumerary teeth, neither such conditions mentioned above were evident with these cases.

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