|Year : 2013 | Volume
| Issue : 1 | Page : 50-52
Nonsyndromic hypohyperdontia: Report of a case
Santanu Mukhopadhyay1, Bidyut Chakraborty2, Pinaki Roy3
1 Department of Pedodontics, Burdwan Dental College and Hospital, Burdwan, West Bengal, India
2 Department of Oral Pathology, Burdwan Dental College and Hospital, Burdwan, West Bengal, India
3 Department of Orthodontics, Burdwan Dental College and Hospital, Burdwan, West Bengal, India
|Date of Web Publication||30-Dec-2013|
18/1c Diamond city (N), 68 Jessore Road, Kolkata - 700 055, West Bengal
Source of Support: None, Conflict of Interest: None
Simultaneous occurrence of supernumerary teeth and hypodontia is rare. Both represent numerical alteration of human dentition. Hypohyperdontia appears to be more common in certain syndromes like cleft lip and palate, cleidocranial dysplasia, Down syndrome, etc. In the general population, its prevalence is rare. Teeth most commonly affected by hypohyperdontia are maxillary and mandibular mesiodens, second premolars mandibular central incisors and maxillary lateral incisors. Hypohyperdontia in the same arch is very rare. Here we described a case of a 12-year-old girl with hypohyperdontia. Radiographic examination revealed that she had mesiodens and agenesis of a maxillary lateral incisor and all four third molars.
Keywords: Agenesis, hypohyperdontia, maxillary lateral incisor, mesiodens, third molar
|How to cite this article:|
Mukhopadhyay S, Chakraborty B, Roy P. Nonsyndromic hypohyperdontia: Report of a case. Niger J Exp Clin Biosci 2013;1:50-2
| Introduction|| |
Numerical alteration of teeth is common in the permanent dentition. The term "hypodontia" denotes congenital absence of teeth. A tooth is said to be congenitally missing when it is not detected clinically and radiographically, excluding a history of tooth loss due to trauma, or extraction. Agenesis of one or few teeth, usually less than six in number, is termed hypodontia.  The term oligodontia denotes more than six missing teeth excluding third molars. Anodontia describes complete absence of teeth, and it is extremely rare. Tooth agenesis is more common in the permanent dentition than in the primary dentition. The teeth most commonly affected by hypodontia are third molars. The frequency of third molar agenesis ranges from 9% to 30%. 
Hyperdontia or supernumerary teeth indicate excess in tooth number. Supernumerary teeth are teeth present in addition to the normal series. The most common site of occurrence of supernumerary teeth is palatal midline where it is termed as "mesiodens." Prevalence of mesiodens in general population is 0.8%. 
Although both hyperdontia or supernumerary teeth and hypodontia display numerical alteration, they represent opposite extremes of spectrums in the development of dentition.  The term hypohyperdontia was first coined by Gibson.  The condition is seen in both primary and permanent dentition, and may affect maxilla, and/or mandible. The simultaneous existence of hypodontia and supernumerary teeth in the same arch is rare. ,,,,,,,, Even rarer is the case of concomitant hypohyperdontia in the maxillary dental arch of a girl.
| Case Report|| |
A 12-year-old girl reported with a complaint of decayed back tooth. Clinical examination showed a carious left mandibular primary second molar. The patient appeared normal for her age, and was a student of class six. Her medical history and family history were not significant. She was the only child born of a nonconsanguineous marriage. Intraoral examination revealed that the patient was in late mixed dentition stage. The maxillary right permanent lateral incisor had not erupted in the oral cavity [Figure 1]. Instead, her primary right maxillary canine was present in place of maxillary left lateral incisor. Parents and the patient gave a negative history of tooth loss due to trauma or extraction.
|Figure 1: Periapical radiograph showing incompletely formed mesiodens and agenesis of right maxillary permanent lateral incisor|
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Intraoral periapical examination revealed an impacted incompletely formed mesiodens positioned between the roots of the maxillary central incisors. The right permanent maxillary lateral incisor was not visible in the radiograph [Figure 2]. Panoramic radiograph also displayed absence of a permanent maxillary lateral incisor [Figure 3]. Orthopantomogram did not show the incompletely formed mesiodens, possibly because of superimposition of the roots of maxillary permanent central incisors. Panoramic radiograph indicated agenesis of all third molars in this patient.
|Figure 2: Intraoral photograph showing missing right permanent maxillary lateral incisor|
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|Figure 3: Orthopantomogram indicating agenesis of maxillary permanent lateral incisor and all third molars|
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Based on history, clinical and radiological examination, a diagnosis of hypohyperdontia was made. The incompletely formed mesiodens, and carious primary mandibular second molar tooth were extracted under local anesthesia. The condition was explained to the parents, and regular follow up till the exfoliation of primary canine were advised. Institutional review board had approved this case study after obtaining informed consent from the parents.
| Discussion|| |
Mesiodens may appear in several forms like conical, supplemental, and tuberculate type and a majority of them stay impacted.  Although midline supernumeraries may remain asymptomatic, most of them are not free from complications. Clinical complications associated with this anomaly are impaction and rotation and even root resorption of adjacent teeth, diastema formation, and in some cases cyst formation.  In this case, conical mesiodens was not erupted, inverted in position, and was asymptomatic.
The reported prevalence of hypodontia is 2.8% to 7.4%.  In Caucasian population, mandibular second premolar and maxillary lateral incisor are the most frequently missing teeth, whereas in Asian population, mandibular incisor is most often affected by hypodontia.  Although absence of third molars is not uncommon in contemporary human populations, agenesis of all four third molars is rare, accounting for only 2% of cases.  Moreover, in this patient agenesis of maxillary lateral incisor and all four third molars support the observations of Celikoglu et al., who showed that agenesis of 3 and 4 third molars is associated with agenesis of other teeth. 
Concomitant occurrence of hypodontia and supernumerary tooth is uncommon. The exact etiology is not known. Probably genetic and environmental factors play important role in its development.  The condition may arise from disturbances in migration, proliferation, and differentiation of neural crest cells during the initiation of odontogenesis. ,,,,
The prevalence of hypohyperdontia ranges from 0.002% to 3.1%.  Varela et al. studied records of 2108 orthodontic patients and observed 7 (0.33%) hypohyperdontia cases.  Males appear to be more frequently affected than females in their study. Prevalence of hypohyperdontia in the general population is even rarer.
Manjunatha et al. described a case of hypohyperdontia in a 26-year-old male patient with absence of mandibular central incisors and presence of a premaxillary supernumerary tooth.  Sharma observed two cases of hypohyperdontia, where both patients had premaxillary supernumerary teeth.  One of them exhibited missing mandibular second premolar. The other patient showed agenesis of permanent mandibular lateral incisor. Nirmala et al. highlighted a case showing agenesis of both maxillary canines and mesiodens.  Hypodontia and hyperdontia in the same arch is very rare. Agenesis of mandibular permanent central incisor with mandibular mesiodens was reported by Das et al.,  Gibson,  and Verma et al.  Segura et al. reported a case very similar to the one described here showing mesiodens with agenesis of a lateral incisor in the premaxillary area. 
The condition is usually asymptomatic and discovered during clinical and radiographic examination of oral cavity for other purposes. Thus when a numerical anomaly is observed, entire tooth bearing area should be examined to rule out presence of other anomalies. Hypohyperdontia is frequently associated with various syndromes like, cleft lip and palate, Down syndrome, Ellis van Creveld syndrome, cleidocranial dysplasia, etc.;  in our case, the patient was not suffering from any syndrome.
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[Figure 1], [Figure 2], [Figure 3]