An unusual occurrence of bilaterally geminated mandibular second premolars resulting in premolar molarization: A case report.

Gemination refers to an attempt by a single tooth bud to divide, with a resultant formation of either a large tooth with a bifid crown or two completely divided teeth throughout the crown and root. This report describes a rare case of bilateral gemination of permanent mandibular second premolar tooth giving rise to molarization of premolars. The mesiodistal width of these teeth is similar to mandibular molars, but the cervicoocclusal width is lesser than that of the molar tooth. This paper also discusses the potential orthodontic, periodontal, and endodontic complications of premolar molarization.

INTRODUCTION

Developmental dental disorders occurs either due to the abnormalities in the differentiation of the dental lamina and the tooth germs (anomalies in number, size and shape) or to abnormalities in the formation of the dental hard tissues (anomalies in structure).[123] Fusion has been described as a developmental anomaly characterized by the union of two adjacent teeth. This union of two separate tooth germs may be either complete or incomplete. Fused teeth have separated or shared pulp chambers and canals.[4] Gemination is defined as an attempt by a single tooth bud to divide, with a resultant formation of either a large tooth with a bifid crown or two completely divided teeth throughout the crown and root.[5] In fusion, the crowns are united by enamel and/or dentine, but there are two roots or two root canals in a single root. In contrast, in gemination, the structure most often presents two crowns, either totally or partially separated, with a single root and one root canal. In cases where union of a normal tooth bud to a supernumerary tooth germ occurs, the differentiation between fusion and gemination becomes difficult.[6] For better understanding, a tooth was recognized as fused if its crown and root were enlarged and the tooth count was less than one. A tooth was recognized as geminated if its crown was enlarged with a normal root and the tooth count was normal.

Gemination is observed both in the primary and permanent dentition. Gemination when occurs in the anterior region can cause unpleasant esthetic appearance due to irregular morphology. Moreover, if gemination presents with a deep groove, these teeth may be susceptible to caries and periodontal disease.[7] Gemination is more frequent in primary than in permanent teeth. Geminated teeth have a characteristic appearance; the mesiodistal diameter of the clinical crown is larger than normal, and from the incisal edge to the apex of the root a groove of unequal depth divides the tooth into two, usually unequal parts. The frequency of gemination or fusion ranges from 0.01-0.04% in the primary, and 0.05% in the permanent dentition and the bilateral presentation is rare.[3] Gemination rarely occurs in mandibular second premolar region and can cause the appearance of molar-like premolar. This anomaly known as molarization of premolars have been infrequently described in the dental literature.[89] This paper presents an unusual case of bilaterally geminated mandibular second premolar tooth giving rise to molarization of premolars.

CASE REPORT

A 27-year-old, healthy male was reported with the chief complaint of pain in the lower left back tooth region for the past 1 week. Following a clinical examination, molar resembling second premolar tooth were seen in the left mandibular region. A thorough clinical examination confirms the presence of molar resembling second premolar tooth also in the right quadrant due to gemination. This molar resembling second premolar tooth gives the impression of four molars [Figure 1] in both the quadrant. The involved teeth had normal morphology; crowns and roots were significantly developed but smaller in size. The length of the root was normal relative to its crown. The root apex was completely developed. The panoramic radiograph [Figure 2] reveals the presence of single root and single root canal in both the involved mandibular second premolar teeth.

Figure 1

Occlusal photograph showing premolar molarization in both the quadrants of the mandible

Figure 2

Panoramic radiograph revealing premolar molarization in the mandible

DISCUSSION

Fusion and gemination are two different morphological dental anomalies, characterized by the formation of a clinically wide tooth. Gemination occurs when two teeth develop from one tooth bud and, as a result, the patient has a larger tooth but a normal number, in contrast to fusion where the patient would appear to be missing one tooth.[12] Fused teeth arise through union of two normally separated tooth germs, and depending upon the stage of development of the teeth at the time of union, it may be either complete or incomplete. In geminated teeth, division is usually incomplete and results in a large tooth crown that has a single root and a single canal.[610]

Gemination is usually asymptomatic. The possible complications with geminated tooth are the presence of labial and lingual vertical grooves on the crown surface. These grooves are pronounced in cases of incomplete fusion. Since these grooves are difficult to clean, caries may result. Placement of a sealant or composite material into these grooves decreases the caries risk.[11] If these defects are very deep and extend subgingivally, the possibility of bacterial plaque accumulation is quite high. Strict oral hygiene is imperative to maintain periodontal health. Furthermore, gemination may have an adverse effect on occlusion, causing deviation, and sometimes, delaying the eruption of other teeth with esthetic problems resulting from tooth. Orthodontic and prosthodontics management should be considered to ensure functional occlusion and improve esthetics.[12]

In this case report, we have presented an unusual case of bilateral gemination of mandibular second premolar tooth. This phenomenon has been rarely described in the dental literature and is referred as molarization of premolars.[89] The mesiodistal diameter of the tooth crown is larger than the average size of mandibular second premolar tooth, but similar in size when compared with that of the mandibular molars [Table 1]. The cervicoocclusal width of these teeth is lesser when compared to the molars [Table 2]. Crowding is evident in the mandibular right quadrant due to the unusually large size of mandibular second premolar. This molarization of premolars can be associated with any syndromes or it may be asyndromic.[9] Our patient had no associated syndrome.

Table 1

Comparison of the real values between the mesiomolar and the other molars in the lower left quadrant

Table 2

Comparison of the real values between the mesiomolar and the other molars in the lower right quadrant

CONCLUSION

The dentist must be familiar with dental anomalies like gemination and fusion, which can influence tooth alignment, and interdigitation, arch symmetry, appearance, and associated periodontal tissues. A multidisciplinary approach comprises of conservative, endodontic, prosthodontics, periodontic, and orthodontic considerations are required for the successful management of these cases.