|Year : 2012 | Volume
| Issue : 3 | Page : 190-194
Idiopathic nonsyndromic tooth agenesis: A report of rare three
Mamta Dali1, Robin Singh2, Deependra Naulakha3
1 Department of Pedodontics and Preventive Dentistry, Nobel Medical and Dental College and Teaching Hospital and Research Centre, Biratnagar, Nepal
2 Department of Prosthodontics and Implantology, Nobel Medical and Dental College and Teaching Hospital and Research Centre, Biratnagar, Nepal
3 Department of Conservative Dentistry and Endodontics, Nobel Medical and Dental College and Teaching Hospital and Research Centre, Biratnagar, Nepal
|Date of Web Publication||11-Jun-2013|
Department of Pedodontics and Preventive Dentistry, Nobel Medical and Dental College and Teaching Hospital and Research Centre, Biratnagar
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Tooth agenesis is a common developmental anomaly that appears in 2.2-10% of the general population (excluding agenesis of third molars). Congenital tooth agenesis can be either hypodontia (agenesis of fewer than six teeth excluding third molars) or oligodontia (agenesis of more than six teeth excluding third molars). Oligodontia can occur either as an isolated condition (nonsyndromic oligodontia) or it can be associated with cleft lip or palate and other genetic syndromes (syndromic oligodontia). The exact aetiology of oligodontia is unknown. The management includes various procedures such as restorative, surgical, and orthodontic to improve the aesthetics and function. This article reports rare three cases of congenitally missing permanent teeth with over-retained deciduous dentition and review the literature citing its etiology, clinical implications, and management.
Clinical relevance to interdisciplinary dentistry
- The timing of diagnosis is not only important for choosing an appropriate treatment plan, but also for obtaining successful treatment results.
- The missing teeth, abnormal occlusion, or altered facial appearance may cause psychological distress in some or all patients.
- Treatment includes multidisciplinary team approach of pedodontists, orthodontists, oral and maxillofacial surgeons, and prosthodontists to restore aesthetics, functional, and psychological reasons depending on the severity of the condition and patient's perceived need for care
- The treatment not only improves speech and masticatory function, but also has psychological implications that may greatly help in regaining self-confidence.
Keywords: Congenital, hypodontia, nonsyndromic, oligodontia, tooth agenesis
|How to cite this article:|
Dali M, Singh R, Naulakha D. Idiopathic nonsyndromic tooth agenesis: A report of rare three. J Interdiscip Dentistry 2012;2:190-4
| Introduction|| |
Dental agenesis is the most common developmental anomaly in humans, often presenting a significant clinical problem. It is classified according to the number of missing permanent teeth excluding the third molars.  Hypodontia is used to describe the absence of one or few teeth, oligodontia is used for agenesis of numerous teeth (more than six teeth) excluding the third molars and anodontia is the extreme of oligodontia where there is total absence of any dental structure.  Oligodontia is also known as partial anodontia, severe or advance anodontia.  Some of them also refer this as selective tooth agenesis.  According to different authors, the frequency of hypodontia is 1-10% and oligodontia 0.1-0.9%. , Anodontia occurs very rarely (17 cases were described over the last 50 years).  Oligodontia may occur as a part of a genetic syndrome, as a nonsyndromic isolated familial trait, as an infrequent finding or as an isolated condition that has been linked to mutations of the MSX1and PAX9. 
The list of all the genes and molecular pathways involved in tooth agenesis are shown in [Table 1]. In addition to genetic factors, the congenital absence of teeth may result from disturbances during the initial stages of tooth development such as trauma, radiation, metabolic disorders, localized inflammation, infectious disease such as syphilis, severe intrauterine disturbances, systemic problems, and idiopathic. 
|Table 1: List of all the genes and molecular pathways involved in tooth agenesis|
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Syndromic and nonsyndromic form of oligodontia can be differentiated by conducting thorough physical examination of hair, nails, sweat glands, eyes, and checks for any congenital disorders. For the orthodontist, the subject of the congenital absence of teeth has direct clinical importance. Treatment planning and space management for patients during the mixed dentition period must obviously include an evaluation of the number of teeth in both jaws. Knowledge of a congenitally absent tooth in one position should lead the clinician to consider the size and number of the remaining teeth.
The aim of this article is to report rare three cases of congenitally missing permanent teeth with over retained deciduous dentition and to review the literature citing its etiology, clinical implications, and management.
| Case Reports|| |
A 10-year-old male patient reported to the Department of Pediatric Dentistry, College of Dental Sciences, Nobel Medical College, Biratnagar, Nepal, complaining of space in the lower anterior teeth. Clinical examination revealed that intraorally there was the presence of retained conical-shaped maxillary and mandibular incisors with missing maxillary both central incisors and with complete set of other remaining primary teeth [Figure 1]a-c. Dentition was characterized with generalized spacing. Extra oral examination revealed concave profile with hypoplastic maxilla and a relative prognathic mandible [Figure 2]. No other abnormalities as such were observed that are associated with typical ectodermal dysplasia. The child was born to nonconsanguineous parents. The pregnancy and delivery were uneventful. There was no history of any severe systemic diseases. The oral hygiene was good with no clinically visible caries and the gingival tissues appeared healthy. Radiographic examination in orthopantomogram (OPG) revealed erupted complete set of primary teeth with missing maxillary both central incisor and right lateral incisor and complete absence of permanent tooth buds [Figure 3]. There was no evidence of root resorption with retained primary teeth. According to the past dental history given by the patient's mother, there was physiologic exfoliation of primary maxillary both central incisor and the permanent teeth did not erupt after the shedding in the maxillary anterior region. Based on clinical and radiological examinations, a diagnosis of nonsyndromic oligodontia was made. The line of treatment planned for the above-reported case was to restore the missing maxillary right incisor with removable partial prosthetic appliance as our patient was in the adolescent age group. The patient is to be monitored every 6 months to determine the need to refit or remake of removable partial prosthetic appliance. Implants and fixed prosthesis are recommended later in life after the complete growth of the jaw bones.
|Figure 1: (a) Clinical photograph showing conical shaped deciduous maxillary incisors. (b) Clinical photograph showing missing 55, 56, and 65. (c) Clinical photograph showing generalized spacing between teeth and note microdontia|
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|Figure 3: OPG exhibiting retained deciduous teeth without root resorption and complete agenesis of permanent tooth buds|
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A 15-year-old male patient reported for oral prophylaxis. On clinical examination, retained deciduous mandibular both second molar with dentinal caries were found. There was no evidence of mobility with retained deciduous molars. The patient was generally healthy. The medical history did not provide any essential information explaining the cause of agenesis. OPG revealed congenitally missing tooth buds of 35, 38, and 45 [Figure 4]. All other permanent teeth were erupted except that of the third molars. Patient had been informed about the absence of both permanent second premolar. As the retained deciduous molars were still firm without evidence of root resorption, composite restoration after excavation of dentinal caries was done at present. For this case, in the future, once the primary molars undergo exfoliation, fabrication of removable or fixed partial prosthesis or orthodontic closure of the space was planned. Patient was kept under observation, but he did not return back for follow up.
|Figure 4: OPG shows the absence of tooth buds 35, 45 and also note the complete absence of tooth bud of 38|
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A 14-year-old male patient reported for routine dental check up. Intraoral examination showed the presence of retained deciduous molars bilaterally on maxillary and mandibular arches with no mobility [Figure 5]a and b.
|Figure 5: (a) Clinical photograph showing retained 55 and 65. (b) Clinical photograph showing retained 75 and 85|
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Permanent maxillary and mandibular, central, lateral, canine, first premolar, first molar and second molar, were clinically present. His past medical history was noncontributory and family history revealed that he was born to nonconsanguineous marriage with normal delivery and no one in his family have congenitally missing teeth. The patient had no history of trauma or extractions. Panaromic examination revealed congenital agenesis 25, 35, and 45 [Figure 6]. The maxillary and mandibular arches were symmetrical. The oral hygiene was good with restoration on retained right maxillary second molar and the gingival tissues appeared healthy. Patient had been informed about the congenital absence of teeth. As there was no evidence of root resorption and patient was not willing for any further treatment; no treatment was done at present. Treatment objective in this case was to maintain primary teeth by protecting the thin enamel cap and dentin from occlusal abrasion and trauma. So ultimately in this case, treatment that was planned was to maintain primary teeth as long as possible followed by prosthetic replacement.
| Discussion|| |
Tooth agenesis is defined as a common anomaly of human dentition characterized by the developmental absence of one or more teeth.  Oligodontia is defined as the congenital absence of 'many' teeth, without any specification as to the meaning of 'many', usually associated with systemic manifestations.  Frequency of congenitally missing teeth was higher in girls than in boys in one of the studies on oligodontia patients. However, in another study there was no significant difference.  Data from the Danish school children study showed that condition is more frequent in girls than in boys.  The inborn lack of tooth buds may appear as isolated defect or may be accompanied with pathological syndromes [Table 2]. ,
|Table 2: Dental manifestations are seen in several syndromes along with malformations of other organs|
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Severe hypodontia or oligodontia is often associated with conical teeth, microdontia, and delayed eruption of permanent teeth, an increased freeway space and retention of deciduous teeth. , Garn and LewisBaum  and Cohen  noted changes in tooth morphology and size of teeth in persons with tooth agenesis. They reported a diminution in size of the associated teeth, particularly in the mesiodistal dimension. Tooth agenesis has also been reported in association with taurodontism. 
In all the reported cases here, the patient was ruled out for being associated with any syndrome and systemic disorder. Thus, congenital lack of permanent teeth without any systemic disorder or syndrome was suggestive of idiopathic non syndromic tooth agenesis in permanent dentition. However in Case 1, we observed that tooth agenesis was associated with microdontia and generalized spacing.
Congenital agenesis of teeth can create dental and facial disfigurement, which can lead to social withdrawal, especially in adolescent years. Treatment in all the presented three cases includes multidisciplinary team approach of pedodontists, orthodontists, oral and maxillofacial surgeons, and prosthodontists to restore aesthetics, functional, and psychological reasons depending on the severity of the condition and patient's perceived need for care. 
Factors to be taken into account before treatment planning includes age of the patient, number and condition of retained teeth, number of missing teeth, condition of supporting tissues, the occlusion, and the interocclusal space. 
Endo et al. have concluded from their study that, before planning-implementing orthodontic treatment on a patient with congenital missing incisors, some factors such as retroclination of alveolar bone and reduced mandibular alveolar bone area should be taken into consideration, as these may affect the treatment outcome. 
Treating such patient requires a thorough knowledge of growth and development and long-term follow up is necessary for the modification and/or replacement of the prosthesis. Adjustments related to fit of prosthesis and occlusion must be monitored periodically at regular intervals due to jaw growth. When growth is stabilized, osseointegrated implants may be an alternative aid to support, stabilize, and retain the prosthesis.  There are also reports on teeth autotransplantation. It applies to patients with hypodontia in one arch and crowded teeth in the other. 
Considering research supports, the congenital absence of teeth can result in minimal volume of bone for the placement of endosseous implants in locations favorable for subsequent restorations. Also, craniofacial growth will necessitate remake and redesign of the prosthesis as growth occurs. But there are other reports showing good results with implants. , If implant-supported prosthesis were shown to have positive effects on craniofacial growth, social development, self image, and food choice of a patient, their use might be routinely recommended in younger patients with the absence of teeth. With the advent of new designs in dental implants and their abutments, it is possible to consider replacing missing teeth with implant borne prosthesis. 
Studies have shown that retained deciduous molars have potential chances to result into infraocclusion and ankylosis as the child reaches to the adult age. Infraocclusion deteriorates with increasing age can create greater consequence in young children because there will be increased vertical compensatory eruption of adjacent teeth during continued growth to magnify the submergence. Malmgren et al. have recommended decoronation procedure for such cases that involves removal of the crown and leaving the root in place to preserve alveolar bone height and width or to eliminate the need for alveolar ridge augmentation prior to future implant placement.  However, scientific study of its effectiveness is lacking.
In our reported cases, as patients reach adolescence, conservative fixed prosthetic replacement of missing teeth is the treatment of choice for Case 1, whereas in the Case 2 and Case 3 decoronation followed by comprehensive orthodontic treatment to close space and advanced treatment strategy such as use of osseointegrated implants are the treatments of choice. Depending upon the extent of the severity, orthodontists team up with prosthodontists in treating such cases. Thus, it is the general dentist's responsibility to identify these patients for early referral to receive multidisciplinary treatment before any complications can occur.
| Conclusion|| |
Careful treatment planning and current understanding of rare conditions like tooth agenesis is important, because there is a need to deal with not only the immediate, but also the long-term adverse implications. Hence, multidisciplinary treatment planning that takes account of established and emerging techniques needs to be practiced. Patient with tooth agenesis may not only have functional problems but also psychological distress that requires early diagnosis and proper evaluation to improve oral health and psyche of the child.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6]
[Table 1], [Table 2]