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Case report: a rare occurrence of non-syndromic hypo-hyperdontia in the mandibular anterior region.


Numeric anomalies in the human dentition are quite a common occurrence in the general population. When fewer than the normal complement of teeth develop, 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 extremes of the spectrum in the development of the dentition [Anthonappa et al., 2008]. The literature contains numerous reports of exclusive occurrence of these anomalies; however coexistent oligodontia, hypodontia and supernumerary teeth or hyperdontia is a rare mixed anomalous condition of the human dentition [Das et al., 2006]. Even rarer is the presence of this condition in the same area of a dental arch and very rare is the occurrence of this condition in the mandibular anterior region [Nayak et al., 2010].


The aetiopathogenesis of this simultaneous hyper-hypodontia is obscure [Ratna, 1988]. 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 [Sharma, 2001]. Very few cases have been reported with this condition in the literature and this is the fifth case to be reported with these two anomalies manifesting in the mandibular anterior region. The rarity of this condition of mixed numerical superiority and inferiority of the human dentition in the mandibular incisor region prompted this report.

Case report

History: A 15 1/2-year male reported to the Dept. of Paedodontics and Preventive Dentistry (Sri Ganganagar, India) with a chief complaint of yellowish brown stains in his maxillary and mandibular teeth for the previous 3 to 4 months. Clinicsl examinations revealed moderate amounts of calculus and yellowish brown stains in maxillary and mandibular teeth, as the patient was not maintaining his oral hygiene properly. He said that he brushed his teeth about once every two days using a horizontal brushing technique. 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 non-contributory. The patient was the younger of two siblings born to parents of a non-consanguinous marriage. Complete physical examination revealed no syndromic features. The boy was of normal build and height and with a normal I.Q. All vital signs were within normal limits. Haematological and serological values were within normal limits. Ultrasound examination of the abdomen did not reveal abnormalities of the kidney, liver, intestine, genitourinary tract etc.



Intra-oral examination: Soft tissue examination showed reddish, soft, oedematous marginal gingivae of the molars with an absence of stippling. Hard tissue examination revealed the absence of the mandibular central incisors bilaterally and presence of a microdont conical shaped supernumerary tooth in the midline [Figure 1]. The morphology of the clinical crowns of the two incisors present and the absence of spacing between the incisors and canines indicated the congenitally missing central incisors.

Radiographs: An intra-oral periapical radiograph of the lower anterior region showed the absence of 31 and 41. There was a conical shaped mesiodens with complete root formation and with no evidence of any pathologic periapical changes [Figure 2]. The close approximation of the roots of the mesiodens and incisors, and no spacing between the incisors and canines, highlighted the absence of the central incisors.

An orthopantomogram confirmed the absence of both mandibular incisors and the presence of a mesiodens in the midline. Other findings in the orthopantomogram were within normal limits considering the boy's age [Figure 3].

Diagnosis: Based upon the history and clinical examination, a provisional diagnosis of mandibular hypo- and hyperdontia and chronic generalised gingivitis was made and the differential diagnosis of orodigitofacial dysostosis, Hallerman Streiff and Cleidocranial dysplasia syndromes were considered. Based upon the history, clinical features and radiological investigations the final diagnosis of mandibular anterior hypohyperdontia was made.

Treatment: The treatment of choice here would have been to restore the mesiodens to the appearance of a normal incisor. Although this would have been a centrally placed 'incisor' the alignment in the arch would not have appeared abnormal. However, while this approach to treatment was fully explained to the patient he refused. Accordingly, the only dental care provided was a full-mouth prophylaxis with scaling and removal of calculus to improve the gingival condition. Class I dental caries were observed in maxillary right and left first molars which were restored with composite restorations. Oral hygiene instructions were given.

Follow-up: The patient has been followed-up every six months for over two years. His intra-oral health remains good with regular re-inforcement of oral hygiene. However, he still refuses any aesthetic restoration of the mesiodens. Composite restorations were checked for microleakage and secondary caries. Restorations were intact, without any secondary caries. Oral prophylaxis was performed at each visit, to maintain the oral hygiene status of the patient. The patient followed the oral hygiene instructions at home. There has been no evidence of development of any other new carious lesions intra-orally.


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 [Nayak et al., 2010, however, now the preferred term is "hypo-hyperdontia" as suggested by Gibson and reported by Anthonappa et al., [2008].

The exact aetiology 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, Hallerman Streiff, cleidocranial dysplasia syndrome, Ellis van Creveld, Down syndrome, cleft lip and palate, and many others [Zhu et al., 1996; Anthonappa et al., 2008; Varela et al., 2009]. The reported prevalence for hypo-hyperdontia from various studies has been calculated to range from 0.002% to 3.1% [Anthonappa et al., 2008].

Hypo-hyperdontia does not usually manifest in the same arch and very rarely in the same area of an arch [Das et al., 2006; Anthonappa et al., 2008]. Other than the case described herein, only four other cases have been reported with involvement of the mandibular anterior region, to the best of our knowledge, [Das et al., 2006]. Most of the reports suggest the supernumerary tooth occurs most commonly in the maxillary arch, in particular the premaxillary region (95%), followed by mandibular premolar and maxillary molar regions [Zhu et al., 1996; Anthonappa et al., 2008; Varela et al., 2009]. In Asian populations, the mandibular incisors are the most commonly missing teeth, followed by the mandibular second premolars [Nagaveni and Umashankara, 2009].

In the present case there were missing mandibular central incisors; however the supernumerary tooth was a mandibular mesiodens, a rare occurrence by itself [Sharma, 2001; Zengin, 2007]. Similar cases were observed by Das et al. [2006] and Karthik et al. [2011]. Nayak in 2010 observed the coexistent hypo-hyperdontia with missing lateral incisors and erupted mandibular mesiodens. Another consideration of this case is that the size of the two incisors present could be thought to be rather larger than expected. It might be that these teeth represent the full fusion of the first and second mandibular incisor tooth germs to produce a larger than normal incisor. However because the radiographs indicate normal single root morphology this suggestion is speculative.

Patients with hypo-hyperdontia usually do not present any symptoms and are detected during examination for other causes or on radiographic examination of the jaws [Sharma, 2008; Raghavan, 2009]. The current case was only recognised when the patient came for oral prophylaxis.

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 a single image [Marilia, 2005]. Additional information about the root morphology and root development can be obtained using periapical views. In the present case, the age of the patient (15 1/2 years) precluded any possibility of late development of at least the mandibular central incisors, as some radiographic evidence would have been noted. However, it should be emphasised 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.

Treatment: To ensure optimum function and aesthetics, the patient was advised to have aesthetic rehabilitation for the mandibular anterior region, but he refused. This was unfortunate as the appearance of a conical mesiodens detracts from the alignment of the mandiculr teeth. Under other circumstances the placement of a matched incisor crown or composite resin build-up would have been ideal.


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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K. G. Verma *, P. Verma **, S. Rishi **

Depts. of * Paedodontics and Preventive Dentistry, ** Oral Medicine and Radiology, Surendra Dental College & Research Institute, Sri Ganganagar (Rajasthan), India.

Postal address: Dr. K. Gupta Verma, 52- Satnam Nagar, P.O Model Town,

Jalandhar City, Punjab-144003, India.

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Author:Verma, K.G.; Verma, P.; Rishi, S.
Publication:European Archives of Paediatric Dentistry
Article Type:Case study
Geographic Code:9INDI
Date:Feb 1, 2012
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