|CASE IN POINT - ENDODONTICS
|Year : 2016 | Volume
| Issue : 4 | Page : 217-220
Unilateral taurodontism in permanent maxillary tooth with hypodontia in lower premolar
IE Neena, Snehayadav, P Poornima, KB Roopa
Department of Pedodontics and Preventive Dentistry, College of Dental Sciences, Davangere, Karnataka, India
|Date of Web Publication||22-Sep-2016|
I E Neena
Department of Pedodontics and Preventive Dentistry, College of Dental Sciences, Pavilion Road, Davangere - 577 004, Karnataka
Source of Support: None, Conflict of Interest: None
Dental anomalies are formative defects caused by genetic disturbances during tooth morphogenesis.Taurodontism is one such anomaly. Taurodontism can be defined as as “a tendency for the body of the tooth to enlarge at the expense of the roots.” Whereas Witkop defined it as “teeth with large pulp chambers in which the bifurcation or trifurcation is displaced apically and hence that the chamber has greater apico-occlusal height than in cynodont teeth and lacks the constriction at the level of cemento-enamel junction (CEJ). The distance from the trifurcation or bifurcation of the root to the CEJ is greater than the occluso-cervical distance.
Keywords: Hypodontia, premolar, taurodontism
|How to cite this article:|
Neena I E, Snehayadav, Poornima P, Roopa K B. Unilateral taurodontism in permanent maxillary tooth with hypodontia in lower premolar. Astrocyte 2016;2:217-20
|How to cite this URL:|
Neena I E, Snehayadav, Poornima P, Roopa K B. Unilateral taurodontism in permanent maxillary tooth with hypodontia in lower premolar. Astrocyte [serial online] 2016 [cited 2021 Dec 1];2:217-20. Available from: http://www.astrocyte.in/text.asp?2016/2/4/217/191043
| Introduction|| |
It was first described by Gorjanovic-Kramberger in 1908 and it aroused interest in researches after it was found in fossil remains of the Neanderthal race at Krapina in Croatia in a 70,000-year-old anthropological specimen. In humans it was described by Pickerill in 1909 and he used the term “radicular dentinoma” to describe the condition. Sir Arthur Keith (1913) later replaced it with the term taurodontism which can be splited as tauros which in Latin means 'bull' and odus meaning 'tooth' or 'bull tooth' in Greek. It was named so because of the morphological resemblance of it to the tooth of hoofed animal, especially bulls.
It is seen in both permanent and primary teeth, affecting single tooth or in several molars in the same quadrant, and can be unilateral or bilateral. However, permanentmolar teeth are most commonly affected and the degree increases from the first to the third molar. According to a survey conducted on patients with a mean age of 21.8 years in northern part of India the prevalence of taurodontism was of 0.4% of which 0.21% were males and 0.19% females.
Hypodontia that is agenesis of tooth less than 6 is other kind of dental anomaly seen with reference to the number of teeth present. The prevalence of hypodontia is 6-8% excluding the third molar. Taurodontism has also been found in association with various dental anomalies, including hypodontia.
Etiology of taurodontism is diverse and unclear. It is commonly attributed to the failure of invagination of Hertwig's epithelial sheath diaphragm to invaginate at the proper horizontal level to form the cynodont. This alteration in the Hertwig's epithelial root sheath involves failure of the epithelial diaphragm to form a bridge prior to dentin deposition resulting in large pulp chambers.
| Case Report|| |
With a chief complain of dull pain in the tooth present in the left upper back teeth region a 12 year old patient visited the Department of Pedodontics and Preventive Dentistry in the College of Dental Sciences along with his guardian. Patient was facing this problem since 1 month with the exacerbation of pain at night and while having food. A routine case history was recorded where it was seen that the patient was a product of non-consanguineous marriage of healthy parents with non-significant family history. Pre and post-natal history were noncontributory. On examining the oral cavity of the tooth of concern it was seen that tooth 65 had a deep dental caries and the tooth was tender on percussion thus indicating chronic apical periodontitis. To confirm the diagnosis and plan the treatment an intraoral periapical radiograph was made. The radiograph showed grossly decayed 65 with resorbed root indicating extraction. Other interesting finding that was noticed was abnormal morphology of 26 which was more or less rectangular shape [Figure 1]. The crown structure was large and the roots were small. The constriction of the crown portion which is normally seen at the area of CEJ was less marked the pulp chamber was large and elongated than seen normally with greater apico-occlusal height extending apically below CEJ. Most importantly the furcation of root shifted apically. Cross examination of the tooth clinically showed no abnormality. This may be because that variation is with the body and root which lies below alveolar ridge and not seen clinically. Therefore, the diagnosis of taurodontism is usually a subjective determination made from diagnostic radiographs.
To rule out presence of similar condition with other molar IOPAR of all permanent molar were made. Out of all only 26 showed this trait, however, other finding that caught notice was agenesis of mandibular left second premolar [Figure 2]. The patient was treated for his chief complain with 65 and parents were informed and explained about the presence of taurodontism with 26 and absence of 35.
| Discussion|| |
Taurodontism is a morpho-anatomical change in the tooth shape characterized by enlargement of the body with shortened roots of the tooth; enclosing comparative large pulp chamber which may approximate of the root apex. The involved teeth appear rectangular in shape instead of tapering towards the roots as the normal constriction at the level of the CEJ is absent in such tooth. It mostly it affects the multirooted teeth where pulpal floor and furcation are displaced apically.
The diagnosis for taurodonism can be based on the distance between the baseline connecting the two CEJ and the highest point in the floor of the pulp chamber; if it exceeds 2.5 mm then the tooth is bull tooth. In the above mentioned case the tooth showed the typical feature of taurodont.
Shaw, in 1928, classified taurodontism based on the degree to which this condition manifests
- Hypotaurodont: the least pronounced form moderate enlargement of the pulp chamber
- Mesotaurodont: moderate form, pulp is quite large and the roots are short, but still separate tooth roots are divided only at the middle third
- Hypertaurodont: is the most severe form that consists of prismatic or cylindrical forms where the pulp chamber nearly reaches the apex and then breaks up into two or four channels.
The theories behind the formation of a taurodont are:
- A mutation resulting from odontoblastic deficiency during dentinogenesis of the roots
- Alteration in Hertwig's epithelial root sheath
- Unusual developmental pattern
- Disrupted developmental homeostasis such as osteomyelitis, high-dose chemotherapy or a history of bone marrow transplantation.
According to Mangion the possible causes of taurodontism might be a specialized or retrograde character or primitive pattern; it might be expressed as a Mendelian recessive trait or an atavistic feature. Fischer (1963), Witkop (1971), Goldstein and Gottlieb (1973) supported genetic to be the cause and Gage (1978) found an association between taurodont and increased number of X chromosome. Blumberg et al. (1971) carried out a biometric study on the trait ascribed taurodontism to a polygenic system, and described the anomaly as a continuous trait without discrete modes of expression. Llamas and Jimenez-Planas (1993) explained failure of Interference in the epitheliomesenchymatose induction result in taurodont.
Taurodontism has been reported in association with few genetic defects like hypodontia, oligodontia, supernumerary teeth, cleft lip/palate, and certain syndromes such as Down syndrome (Trisomy 21), Klinefelter syndrome, Lowe syndrome (Oculo-cerebro renalsyndrome), Smith-Magenis syndrome, Wolf-Hirschhorn syndrome, Seckel syndrome, Williams syndrome, Mohr syndrome (Oral-facial-digital II syndrome), tricho-onycho-dental syndrome (TOD), Tricho-dento-osseous syndrome (TDO), Kabuki syndrome, Apert syndrome, Lenz microphthalmia syndrome, Ellis van Crevel syndrome, McCune-Albright syndrome More Details, Prader- Labhart-Willi syndrome More Details, 47, XXY karyotype (Additional X chromosome), 47, XXX karyotype (Additional X chromosome), amelogenesis imperfect (hypoplastic-hypomaturation with taurodontism), triad of microdontia-taurodontia-dens Invagination, ectodermal dysplasia (e.g. otodental dysplasia, cranioectodermal dysplasia, and Rapp-Hodgkin syndrome) osteoporosis, Thalassaemia major, focal dermal hypoplasia or goltzgorlin syndrome, hypophosphatasia, hyperphosphatasia-oligophrenia-taurodontism, microcephalic dwarfism-taurodontism, dyskeratosis, congenital Epidermolysis bullosa, otodental dysplasia, oculo-dento-digital dysplasia, rapp-hodgkin syndrome, smith-magenis syndrome, van der woude syndrome, X-chromosome aneuploid syndrome with ectodermal defects, and maroteaux-Lamy syndrome.
When non syndromic it is usually associated with missing teeth. According to a survey conducted by Wayne et al. taurodontism was found in 22% of children with a single tooth missing and 52% of children with multiple teeth missing. Whereas survey used a novel biometric method for the assessment of taurodontism and found that 34.8% of 66 patients with hypodontia (0.4% had missing premolars) had at least one mandibular first permanent molar that showed taurodontism compared with only 7.5% of a control group without hypodontia. Survey was conducted in the northern province of India to find an association between taurodontism and abnormal number of teeth. According to the results of the survey total 164 cases showed taurodontism with 62 simultaneous having hypodontia, 9 with oligodontia and 12 patients had supernumerary teeth at the same time. Presence of anomalies in the same patient can be more than being just a chance thus indicating that there is a a preferential association between tooth number polymorphisms and the size, development, and calcification timing of the dentition as a whole including taurodontism. This fundamental association is important to be known as it might help to determine the possible cause of the condition.
Taurodontism shows autosomal dominant or recessive and X_linked type of inheritance or an anomaly of ectodermally derived structure in clinical and molecular studies. The distal-less homeobox gene (DLX3) expressed during root morphogenesis has been associated with taurodontism. Considering agenesis of tooth excluding third molars, permanent lateral incisors and second premolars are the teeth most frequently absent. In cases of nonsyndromic hypodontia, associations with genes such as MSXl and PAX9, which are expressed in early tooth development, have been found. Whereas genes expressed later during root morphogenesis such as ALPL and DLX3 have been identified in taurodontism. These genes, which are expressed at two distinctly different points in time during the entire tooth formation process, are likely to provide the link between hypodontia and taurodontism. Another school of thought is the common ectodermal origin may a link between taurodontism and hypodontia. Other reason be that the syndromes involve ectodermal defects which causes both hypodontia and taurodontism. However in this case the patient didn't had any syndrome thus excluding this possibility.
Apart for being a variation in the shape taurodont can lead to major problem to a dentist. There are higher chances of pulpal exposure due to caries or dental procedure in such cases. Increased bleeding during access opening may be mistaken for perforation. Chances of perforation increases owing to the short roots and apical position of the pulpal floor. In primary taurodont the large bulk of zinc oxide eugenol used to obturate it may take longer time to resorb thus delaying natural exfoliation of the tooth.
It may complicate endodontic as well as prosthetic and/or orthodontic treatment planning. The biggest problem when such teeth is its endodontic treatment; owing to the complexity of the root canal anatomy, potential for additional root canal systems, the proximity of the buccal orifices and difficulty in completely filling of the root canal. Procedure like negotiation, instrumentation and obturation can be challenging to an endodontist. A modified filling technique, which a combination of lateral compaction in the apical region and vertical compaction of the elongated pulp chamber, using the system B device can be used to obturate such teeth. Apart from this use of magnification, ultrasonic irrigationwith 2.5% sodium hypochlorite can be useful to remove the voluminous pulp. On the contraryin cases of hypertaurodont vital pulpotomy instead of routine pulpectomy may be considered as the treatment of choice. For the prosthetic treatment of a taurodont tooth, the post placement for tooth reconstruction should be avoided because of the less surface area embedded in the alveolus thus decreasing the stability. The apical shift of the furcation makes extraction of a taurodont tooth complicated. In contrast, it has also been hypothesized that the large body with little surface area embedded in the alveolus makes extraction less difficult. Taurodont enjoys the favour from a periodontal point of view. For a tooth to be periodontally weak needs to have its furcation involvement; but the furcation of taurodont are too apical to get involved early.
Similar condition may be seen in pseudo-hypoparthyroidism, hypophosphatasia, hypophosphataemic vitamin D-resistant, dependent rickets; however the pulp chamber may be enlarged but the teeth are of relatively normal form. The condition of early stages of dentinogenesis imperfect have similar appearance of large pulp chambers. Also the developing molars may appear similar to taurodonts; but the presence of wide apical foramina and incompletely formed roots helps in the differential diagnosis. It should be noted that taurodontism may be masked by wear-induced secondary dentine deposition, so caution should be employed in interpreting an expression of taurodontism in heavily worn molars.
| Conclusion|| |
Thus the presence of taurodontism is an indicator of developmental instability and tooth agenesis is suggested as an expression of a general abnormality of dental development. Therefore whenever comes across a clinican should be alerted to the possibility of this unusual dental morphology in patients especially presence of other taurodont or missing teeth. Apart from this a taurodont special attention while performing any treatment.
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Conflicts of interest
There are no conflflicts of interest.
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[Figure 1], [Figure 2]