Fused primary first mandibular macromolar with a unique relation to its permanent successors: A rare tooth anomaly

Abstract

Dental anomalies of number and forms may occur in the primary and permanent dentition. Various terms have been used to describe dental twinning anomalies: Germination, fusion, concrescence, double teeth, conjoined teeth, twinned teeth, geminifusion, and vicinifusion. Fused tooth is a developmental anomaly that is seen more frequently in the primary than the permanent dentition. Double tooth involving deciduous anterior teeth is found mostly in the mandible. Very few cases of nonsyndromic double primary molar have been reported in the literature. The succeeding permanent tooth is often found missing congenitally in the same region. This article reports a very rare unilateral occurrence of an anomalous, primary mandibular first macromolar formed by fusion with a dysmorphic premolar like supernumerary tooth in deciduous dentition period. Instead of agenesis of succedaneous tooth, the double tooth has been succeeded by normally developing mandibular first premolar in the same region.

Keywords: Fusion; nonsyndromic; supernumerary.

Figure 1

(a) Clinical picture of the mandibular arch showing unilateral presence of fused macromolar L. Difference in shape can be appreciated by comparing with S, (b) Clinical crown shows extra mesio-lingual cusps of L resembling a rudimentary premolar with abnormal bulge and swelling in relation its attached gingival lingually.

Figure 2

IOPA radiograph showing fused macromolar L, which is partially fused to a supernumerary tooth resembling a bicuspid, with divided pulp chamber and 3 roots. Normally developing 21 can be well appreciated.

Figure 3

Anatomical view of extracted macrodont L, partially fused with an extra rudimentary premolar like tooth with prominent middle lobe, on the lingual aspect of its crown.

Figure 4

Various views of extracted macrodont L (a) Mesial aspect showing crown ridge and part of root of supernumerary rudimentary premolar (b) Lingual aspects showing deep carious lesion (c) Distolingual aspect (d) Occlusal aspect showing full anatomy of partially fused supernumerary rudimentary premolar.

Figure 5

The radiographic image of contralateral right mandibular molar is provided. It has only two roots with nor mal crown dimension which can also be seen in the clinical photograph. The dimension, presence of three roots, site of attachment of premolar and all side image of extracted tooth confirmed the fusion of mandibular first molar with supernumerary tooth.