Famlial nonsyndromic oligodontia.

Oligodontia is one of the most common developmental abnormalities in humans. The present case report highlights the features of oligodontia in a 12-year-old male patient which was managed successfully with multidisciplinary approach. Familial oligodontia represents as an absence of varying numbers of secondary teeth seen as an isolated trait. The advance in the understanding of tooth development and genetic control of tooth morphology not only allows clinical research to broaden the knowledge of tooth agenesis but also provides optimum clinical care.

Introduction

Agenesis of one or more teeth is the most common anomaly of tooth development. The expression of developmentally missing teeth may range from the absence of one or a few teeth to the absence of numerous teeth. Schalk-vander weide defines in her Dutch study, hypodontia of six or more permanent teeth as oligodontia. It is a relatively rare condition affecting 0.1–0.2 % of the population.

Oligodontia can occur as an isolated nonsyndromic condition or as a part of a syndrome. Oligodontia has associated anomalies with a tendency toward delayed tooth formation, reduced tooth size, ectopic maxillary canines, ectopic eruption of other teeth, short roots of teeth, enamel hypoplasia, hypocalcification, dentinogenesis imperfecta, and taurodontism.

Diagnosis and comprehensive management of oligodontia is of a significant challenge to the clinicians. Counseling from a geneticist might be essential to determine whether the specific type of oligodontia is a stand-alone condition or one associated with other anomalies. This article presents a case of familial nonsyndromic oligodontia, where an esthetic and functional dentition was established through restorative and orthodontic intervention.

Case Report

A 12-year-old male patient with an interesting presentation of multiple congenitally missing permanent teeth in maxilla and mandible was referred to the Department of Pedodontics with a chief complaint of forwardly placed upper front teeth. Medical history revealed absence of systemic diseases or syndromes. When questioned about similar presentation in the family, it was found that the maternal grandfather, the mother, and the maternal uncle had missing teeth, which was clinically and radiographically confirmed. [Figures 1–4]

Figure 1

Pedigree chart

Figure 4

OPG of the proband's maternal uncle aged 26 years

OPGs of a family with familial nonsyndromic oligodontia

OPG of the proband's mother aged 37 years

Extraoral clinical examination did not show any developmental anomaly and was noncontributory to the oral findings. Intraoral findings showed retained mandibular primary anterior teeth. The maxillary and mandibular arches showed polidiestema with symmetrical spacing in the anterior region. The oral hygiene was poor, with localized gingivitis in relation to lower anteriors. Retained 75 and 84 were also present. Pulpal involvement of 75 was confirmed in intraoral periapical radiographs. Macrodontia in relation to 46 was evident. A tooth was considered to be developmentally missing when it was not seen clinically or radiographically and the history revealed no previous extraction. Radiographically it was confirmed that 31, 32, 33, 35, 37, 38, and 41, 42, 43, 44, 45, 48, 85 were missing. Pulpectomy and stainless steel crown was done on 75. Patient has been enrolled for orthodontic and prosthetic treatment for esthetic management.

Discussion

Oligodontia may result in significant psychological, dental, esthetic, and functional problems, and is classified as syndromic or nonsyndromic. The present case with congenital lack of 12 permanent teeth without any systemic disorders or syndromes is suggested as isolated or nonsyndromic oligodontia. Missing teeth are a common trait in modern populations and it is often encountered by dental practitioners.[1] Eruption of some teeth may be developmentally delayed by a number of years after the established time and others may show evidence of development as late as a year after the contralateral tooth. The panoramic radiography together with clinical examination of the oligodontia is recommended for the detection or confirmation of dental development and performing the diagnosis.

Numerous studies have reported on the prevalence of oligodontia in different countries, showing some variation in populations and among races. Family studies have shown the frequency of mutation. In Dutch and Danish studies, the prevalence of oligodontia was 0.08% and 0.16%, respectively.[2] The prevalence of permanent tooth agenesis ranges between 1.6% and 9.6%, and the prevalence of deciduous teeth agenesis is lower, ranging between 0.5% and 0.9%.[34]

Several studies have reported that bilateral agenesis of tooth was more common than the unilateral form, which correlates with the current case report.[56] According to recent literature, missing teeth are more common in the maxilla than in the mandible.[6-8] Kirzioglu reported[ that missing teeth are more common in the mandible than in the maxilla. Similar findings have been observed in the present case report. The most affected teeth were maxillary lateral incisors, mandibular and maxillary second premolar, and the least affected teeth were the maxillary central incisors, maxillary first molars, and mandibular canines.

The formation of third molar shows very large variations. Usually at the age of 8–10 years, the first signs of third molars appear on a radiograph and are evaluated after 10 years of age. Hence, third molars have been taken into consideration for the number of missing teeth. Missing teeth may be the result of numerous independent pathologic mechanisms that can affect the orderly formation of the dental lamina, failure of a tooth germ to develop at the optimal time, multi-agent chemotherapy, radiation therapy, fracture, surgical procedures on the jaws, extraction of the preceding primary teeth, lack of necessary space imposed by a malformed jaw, and a genetically determined disproportion of tooth mass and jaw size.

Although tooth agenesis is occasionally caused by environmental factors, in the majority of cases, oligodontia has a genetic basis. In familial oligodontia, the type of inheritance in majority of the families seems to be autosomal dominant with incomplete penetration and variable expressivity. An autosomal recessive model of inheritance is also possible; mutations in transcription factors MSX1 and PAX9 have been identified in families with an autosomal dominant oligodontia. A nonsense mutation in the b-catenin binding protein AXIN2 has recently been detected to cause familial oligodontia.[59]

Oligodontia is associated with malformation of crowns, enamel hypoplasia, and failure of eruption. It occurs with other dental anomalies such as microdontia, taurodontism, talon cusp, macrodontia, and gemination.[10]

No definite etiologic relationship was found between oligodontia and systemic diseases or endocrine disturbances. Missing teeth were the mandibular anteriors, second premolars, second molar, and third molars. As reported in earlier case studies, the remaining teeth had malposition, polidiestema, and malformation. Missing teeth together with abnormal occlusions or altered facial appearance may cause psychological distress in these patients. Thus, an early diagnosis and prompt treatment becomes more important for them. The pediatric dentistthe head of the multidisciplinary team psychologically managed the child and assured him of a normal dentition like his peers.

Conclusion

Successful outcome in the management of patients with oligodontia depends on careful diagnosis and treatment planning which requires cohesive cooperation between specialists of different disciplines. Additionally excellent communication with patients and parents (including informed consent) is necessary, as the treatment duration for patients with oligodontia may extend over many years.