|Year : 2015 | Volume
| Issue : 1 | Page : 44-46
Non-syndromic hypo-hyperdontia in the mandibular anterior region with absence of all four-third molars - A rarity
Department of Pediatric Dentistry, Institute of Dental Sciences, SOA University, Bhubaneswar, Odisha, India
|Date of Web Publication||30-Jul-2015|
Dr. Sonu Acharya
Department of Pediatric Dentistry, Institute of Dental Sciences, SOA University, Bhubaneswar - 751 003, Odisha
Source of Support: None, Conflict of Interest: None
Numeric disturbances in the human dentition are quite a common occurrence in the general population. When less than the normal complement of teeth develops, it is termed as hypodontia, whereas hyperdontia is a condition with an excess number of teeth developing. Therefore, though both conditions manifest as changes in the number of teeth, they represent the opposite ends of the spectrum in the development of the dentition. The literature contains numerous reports of the exclusive occurrence of these anomalies; however coexistent oligodontia, hypodontia, and supernumerary teeth or hyperdontia is a rare manifestation of the human dentition.
Keywords: Hyperdontia, hypodontia, mesiodens, missing tooth
|How to cite this article:|
Acharya S. Non-syndromic hypo-hyperdontia in the mandibular anterior region with absence of all four-third molars - A rarity. Saint Int Dent J 2015;1:44-6
|How to cite this URL:|
Acharya S. Non-syndromic hypo-hyperdontia in the mandibular anterior region with absence of all four-third molars - A rarity. Saint Int Dent J [serial online] 2015 [cited 2019 Oct 19];1:44-6. Available from: http://www.sidj.org/text.asp?2015/1/1/44/161802
Agenesis of teeth in a patient with associated supernumerary tooth/teeth is one of the rare numerical anomalies in human dentition. This numerical anomaly is termed as hypo-hyperdontia  or oligoplieodontia.  Combined hypodontia and hyperdontia is a rare mixed anomaly. Even rarer is the presence of this condition in the same arch and rarest in the mandibular anterior region.  The etiopathogenesis of this simultaneous hyper-hypodontia is obscure. Disturbance in migration, proliferation and differentiation of the neural crest cells, and interaction between the epithelial and mesenchymal cells during the initiation stage of tooth development has been suspected as a possible cause.  Few cases have been reported with the condition manifesting in maxillary arch but rarely in the mandibular arch. 
| Case Report|| |
A 10-year-old male child visited the Department of Pedodontics and Preventive Dentistry, with a chief complaint of pain in the left lower back tooth since 2 days. Clinical examination revealed moderate amounts of calculus and yellowish brown stains in maxillary and mandibular teeth, as the patient was not maintaining his oral hygiene properly. There was also the presence of caries in 74 75 due to which the patient complained of pain. There was no history of trauma, infection or metabolic disorders in his childhood. This was the patient's first dental visit with no prior experience of having undergone any dental procedure. Medical history and family history were noncontributory. Complete physical examination revealed no syndromic features. The boy was of sound physical and mental health. All vital signs were within normal limits. Ultrasound examination of the abdomen did not reveal abnormalities of the kidney, liver, intestine, genitourinary tract, etc. Intraoral soft tissue examination showed reddish, soft, edematous marginal gingivae of the molars with an absence of stippling. Intraoral examination further revealed the absence of the mandibular central incisors and presence of a microdont conical shaped supernumerary tooth in the midline [Figure 1]. There was a conical shaped mesiodens as shown by an intra-oral radiograph too [Figure 2]. An orthopantomogram confirmed the absence of both mandibular incisors and the presence of a conical mesiodens with complete root formation in the midline as well as absence of all four third molars [Figure 3]. The patient had multiple carious lesions in 54, 55, 74, 75, 36, and 46.
| Discussion|| |
The simultaneous occurrence of hypodontia and hyperdontia is an extremely rare anomaly in the human dentition. Many terminologies have been used in the past to describe this condition, such as "concomitant hypodontia and hyperdontia," and oligopleiodontia ("Oligos" meaning few; "Pleion" meaning more or extra in Greek),  however, now the preferred term is "hypo-hyperdontia" as suggested by Gibson  and reported by Anthonappa et al. 
The exact etiology for this condition is unknown and the role played by any specific genes or enzyme defects has not yet been ascertained. Hypo-hyperdontia is rare in isolation and has been associated with over 50 syndromes, notably orodigitofacial dysostosis, Hallermann Streiff, cleidocranial dysplasia syndrome, Ellis van Creveld, Down syndrome, cleft lip and palate, and many others. ,, The reported prevalence for hypo-hyperdontia from various studies has been calculated to range from 0.002% to 3.1%. 
Hypo-hyperdontia does not usually manifest in the same arch and very rarely in the same area of an arch.  Other than the case described herein, only five other cases have been reported with the involvement of the mandibular anterior region, to the best of our knowledge.  Most of the reports suggest that the supernumerary tooth occurs most commonly in the maxillary arch, in particular the premaxillary region (95%), followed by mandibular premolar and maxillary molar regions.  In Asian populations, the mandibular incisors are the most commonly missing teeth, followed by the mandibular second premolars.  In the present case, there were missing mandibular central incisors; however the supernumerary tooth was a mandibular mesiodens, a rare occurrence by itself.  Similar cases were observed by Das et al.  and Karthik et al.  Nayak observed the coexistent hypo-hyperdontia with missing lateral incisors and erupted mandibular mesiodens.  When any numeric anomaly of the dentition is noted, a thorough clinical intra-oral examination is warranted, combined with a judicious use of radiographs. Panoramic radiographs are the best screening modality available by virtue of demonstrating the entire teeth-bearing segment of the jaws and supporting structures in single image.  Additional information about the root morphology and root development can be obtained using periapical views. In the present case, the age of the patient (10 years) precluded any possibility of late development of at least the mandibular central incisors, as some radiographic evidence would have been noted. The association of third molar agenesis with missing teeth from other classes of teeth was shown by Garn et al.  According to them, the association between third molar agenesis and reduction in the number of other teeth fits the hypothesis of a field of variable intensity, which, in its greatest degree of expression, eliminates all four third molar teeth and a maximum number of other teeth. While the degree of independence between these two phenomena may show which hypothesis is correct, the possibility of closely linked genes must also be considered. In this latter event, the monogenic and polygenic hypotheses would be operationally identical. This case presented by us is in accordance with the findings of Garn et al.,  Bailit  and Nuvvula et al.  that third molar agenesis is associated with missing teeth from other classes of teeth. The present case shows agenesis of all the third molars (18, 28, 38, and 48) and the mandibular central incisors (31, 41) with the presence of a midline supernumerary tooth (hypo-hyperdontia). However, it should be emphasized that in most cases supernumerary as well as unerupted teeth go undetected and clinicians have to make the effort to determine these conditions by a thorough clinical as well as radiographic examination. Such rare situations can at times significantly alter the treatment plan and enough latitude should be considered in managing such clinical circumstances.
The major concern for the patient was pain in the lower back tooth on left side for which root canal therapy was done. The patient was also advised for extraction of grossly decayed 55, 73, 74, 75 with nonfunctional removable space maintainers for the extracted teeth as the succedaneous teeth will be erupting soon. Apexification followed by root canal therapy for 46 was also advised. To ensure optimum function and esthetics, the patient was advised to have esthetic rehabilitation for the mandibular anterior region, but he refused. This was unfortunate as the appearance of a conical mesiodens distracts from the alignment of the mandibular teeth. Under other circumstances, the placement of a matched incisor crown or composite resin build-up would have been ideal.
| Conclusion|| |
Due to the rarity of combined hypodontia of the mandibular incisors and the presence of a mandibular mesiodens, treatment of affected children is generally undertaken. Multidisciplinary treatment planning, which takes account of established and emerging techniques, should be considered. Different treatment options that take account of growth and development of the dentition and of the compliance of child can lead to a treatment plan that can produce desirable interim results, which do not compromise any future treatment. Careful treatment planning is important, because there is a need to deal with not only the immediate but also the long-term adverse implications.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]