ORIGINAL Gupta andARTICLE Saxena
Prevalence of Taurodontism and its Association with Various Oral Conditions in an Indian Population Saurabh Kumar Guptaa/Payal Saxenaa Purpose: The aim of this retrospective study was to assess the prevalence of taurodont molars among an Indian population. The goal was also to determine sexual dimorphism, distribution of taurodontism as well as any association between taurodontism and simultaneously occurring syndromes and anomalies. Materials and Methods: Full-mouth periapical radiographs of a total of 1360 patients were screened. A total of 9792 molars (including third molars) were evaluated. The relative incidence and the correlations regarding the location of taurodonts (right versus left side and maxillary versus mandibular) were analysed using the Z test. Results: The overall incidence of subjects with taurodont molars among this Indian population was 2.5% (34/1360). Sexual distribution showed female dominance (21 females, 13 males), but this was statistically insignificant (P > 0.05). Maxillary second molars (35/118) were the most commonly involved teeth, followed by mandibular second molars (32/118). No significant differences were obtained for distribution by side (right vs left; P > 0.05) or interarch distribution (maxillary vs mandibular; P > 0.05). Out of 34 subjects with taurodonts, 50% (17/34) were associated with pyramidal molars and 32.35% (11/34) had impacted molars. Conclusions: Taurodontism is not uncommon in the Indian population and it might be associated with other conditions, such as pyramidal molars and impaction. Further larger scale studies are required to assess its prevalence in the general population and to establish any associations. Key words: anomalies, association, prevalence, pyramidal molars, taurodont Oral Health Prev Dent 2013;11:155-160 doi: 10.3290/j.ohpd.a29363
U
nusually shaped teeth having a cylindrical or prismatic form were described in modern humans by Pickerill (1909) who used the term ‘radicular dentinoma’. Sir Arthur Keith (1913) coined the term ‘taurodontism’ to describe this unusual tooth form. Witkop (1971) defined taurodontism as ‘teeth with large pulp chambers in which the bifurcations and trifurcations are displaced apically, so that the chamber has greater occlusoapical height than in normal teeth and lacks the constriction at cervico enamel junction. The distance from the trifurcation and bifurcation from the roots to CEJ is greater than the occluso-cervical junction.’ Shaw (1928) classified subtypes of the condition as ‘hypotaurodontism,’ ‘mesotaurodontism’ and ‘hypertaurodon-
a
Assistant Professor, Department of Conservative Dentistry and Endodontics, Government College of Dentistry, Indore, India.
Correspondence: Saurabh Kumar Gupta, Department of conservative dentistry and Endodontics, Government College of Dentistry, Sardar Patel Marg, Indore, India 452001. Tel: +91-810-307-8123. Email:
[email protected]
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Submitted for publication: 05.01.12; accepted for publication: 13.06.12
tism’ to more accurately define the degree to which this condition is manifested. Shifman and Chanannel (1978) also included an index to calculate the degree of taurodontism as shown radiographically. The aetiology of taurodontism is unclear. It is thought to be caused by the failure of Hertwig’s epithelial sheath diaphragm to invaginate at the proper horizontal level (Hamner et al, 1964; Terezhalmy et al, 2001). Interference in the epitheliomesenchymatose induction has also been proposed as a possible cause (Llamas and JimenezPlanas, 1993). Other theories concerning the aetiology of taurodontism include ‘a specialized or retrograde character’(Shafer et al, 1999), a primitive pattern (Gregory, 1921), a Mendelian recessive (Shaw, 1928; Mena, 1971) and ‘without doubt, a mutation’ (Shafer et al, 1999). There is a wide range of variability of prevalence from 0.3% in a Swedish population (Bäckman and Wahlin, 2001) to 48% in a Senegalese population (Sarr et al, 2000). Although taurodontism does not involve molars exclusively (Madeira et al, 1986), it
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is found to be significantly more prevalent in second maxillary molars than in other teeth (Toure et al, 2000). Taurodontism appears most frequently as an isolated anomaly. However, its association with several syndromes and abnormalities has also been reported (Shifman and Buchner, 1976; Genc et al, 1999). Taurodontism, although not common, is an important occurrence that may influence dental management of patients; especially endodontic treatment becomes challenging. In view of the wide discrepancies in the reported prevalence in different ethnic groups (Jafarzadeh et al, 2008) and the fact that to date little information is available for the Indian population, this study was undertaken to assess the frequency of taurodontism in a sample of the Indian population. The goal was also to determine sexual dimorphism, distribution of taurodontism as well as any association between taurodontism and simultaneously occurring syndromes and anomalies.
MATERIALS AND METHODS A total of 1360 patients’ retrospective periapical radiographs, which were already recorded in the Government Dental College, Indore, India from June 2009 to July 2010, were screened and examined. Each of these patients had to have a full-mouth series of radiographs, be at least 18 years at the time of radiographic examination and of Indian origin. Personal details including age, sex, race and detailed medical history together with presence of any syndrome or cleft lip and/or palate of all these patients were recorded. Dental history regarding prior extraction or any dental treatment was also noted. The x-ray machine used for tooth analysis was Heliodent DS (Sirona; Bensheim, Germany) (7 mA and 60 kV). Kodak Ultraspeed film (Eastman Kodak; Rochester, NY, USA) was used for image retention. All radiographs were evaluated under optimal conditions using double magnifying glasses and an x-ray viewer (Illuminator 5000, RP Beard; London, UK). Radiographs were inspected by two endodontists (GS and SP) separately. Disagreement in the interpretation of radiographs was discussed between the two investigators until a consensus was reached. The Taurodont Index (TI) established by Keene (1966) and modified by Shifman and Chanannel (1978) was used. They proposed an arbitrary distance of 2.5 mm between the CEJ and the floor of the pulp chamber and assumed that in a taurodont,
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the ratio between the height of the pulp chamber and the distance between the roof of the pulp chamber and the root apex is at least 0.2. The TI has four different categories: hypotaurodont molars with a value of 20% to 29.9%, mesotaurodont molars with 30% to 39.9% and hypertaurodont molars with 40% to 75%. Teeth with values less than 20% are called cynodonts, which thus can be considered normal teeth. The values were recorded for all the molars present in the radiographs. To assess the presence of any associated anomaly, the radiographs were carefully examined for the presence of pulp calcification, pyramidal molars (molars with a fused, single conical root), number of missing (including third molars) or supernumerary teeth and impaction. The relative incidence and distribution of taurodont was analysed using the Z test.
RESULTS The prevalence of subjects with taurodont molars among this Indian population was 2.5% (34/1360). Out of the 34 individuals with taurodont molars, 21 (3.13%) were females and 13 were males (1.89%). However, this difference in sexual distribution was statistically insignificant (P > 0.05, Table 1). Out of a total 9792 molars examined, 1.21% (118/9792) were taurodont with significant female dominance (72 in females and 46 in males) (P < 0.05, Table 1). The distribution regarding location of taurodont molars showed maximum frequency in the second molar region (67/118), followed by the first (28/118) and third molar (23/118) region. Maxillary second molars (35/118) were the most commonly involved teeth, followed by mandibular second molars (32/118), maxillary first molars (17/118), mandibular third molars (14/118) and mandibular first molars (11/118) (Table 2). The Z test showed this predominance of maxillary second molars to be highly significant (P < 0.01) compared to all other molars, except mandibular second molars. Least commonly involved were maxillary third molars (9/118). No significant differences were obtained in distribution by side (right vs left; P > 0.05) or interarch distribution (maxillary vs mandibular; P > 0.05). On analysing the classification of taurodont teeth, hypotaurodontic molars appeared in 51.7% (61/118) of total taurodonts (1.22% of total teeth examined) and were significantly more numerous (P < 0.01) than mesotaurodonts (30.5%; 36/118) and hypertaurodonts (17.79%; 21/118).
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Table 1 Frequency and incidence of taurodont molars in the study group Male n (%) Subjects with taurodont
Female n (%)
13 (1.89)
Total subjects
21 (3.13)
688
Taurodont teeth
672
46 (0.92)
Total teeth
Level of significance (P-value)
34 (2.5)
0.14
1360
72 (1.45)
4988
Total n (%)
118 (1.21)
4808
0.01*
9792
*P < 0.05 is considered to be significant.
Table 2 Distribution of taurodont molars in the present study Total
First molar
Second molar
Third molar
R
L
R
L
R
L
Male
Female
Maxillary
61
7
10
22
13
4
5
25
36
Mandibular
57
7
4
16
16
7
7
21
36
Total
118
14
14
38
29
11
12
46
72
Hypertaurodont
21
2
1
7
4
5
2
12
09
Mesotaurodont
36
3
1
16
8
2
6
15
21
Hypotaurodont
61
9
12
15
17
4
4
19
42
R: right; L: left.
Table 3 Association of taurodontism to other conditions Anomalies considered
Male
Female
Total
Cleft lip and palate
-
1
1
Pyramidal molars
7
10
17
Hypodontia
3
6
9
Impaction
5
6
11
Amelogenesis imperfecta
-
-
-
Pulp calcification
2
5
7
Supernumerary
-
-
-
Total number subjects with taurodontism = 118.
Results regarding the association of taurodontism to other conditions selected in the present study showed that out of 34 subjects with taurodonts, 50% (17/34) also had pyramidal molars and 32.35% (11/34) had impacted molars (Table 3). The presence of hypodontia (26.47%; 9/34) followed by molars having pulp calcification (20.6%; 7/34) in one or more teeth on the same or contralateral side along with taurodontism was observed. Only one female subject had cleft lip and
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palate. No subject selected in the study had amelogenesis imperfecta (AI) or any other syndrome (Table 3).
DISCUSSION Using a periapical radiographic method, this study investigated the occurrence of taurodontism in an Indian population and found that 2.5% of all pa-
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tients and 1.21% of all teeth examined had taurodontism that could potentially affect the various dental procedures. These results were in accordance with previous studies in a German (Bürklein et al, 2011) and Israeli (Shifman and Chanannel, 1978) population. Darwazeh et al (1998) found a higher rate of 8.0% in Jordanian dental patients, whereas MacDonald-Jankowski and Li (1993) reported an even higher rate (46.4%) of taurodontism in an adult Chinese population. The difference might arise from racial differences or differences in diagnostic criteria. In the present study, females presented a higher prevalence of taurodont teeth. Among all molars examined, significant female dominance was seen (P < 0.05). Except for a higher prevalence of taurodontism amongst females in a Chinese sample (MacDonald-Jankowski and Li, 1993) and a German population (Bürklein et al, 2011), no study has found a gender difference for this abnormality. According to the results of present study, maxillary second molars were most commonly affected, followed by mandibular second molars. Our finding of a higher prevalence of taurodonts in the maxillary posterior teeth, especially the second molars, is consistent with that of Toure et al (2000), Darwazeh et al (1998) and MacDonald-Jankowski (1993). In contrast, Shifman and Channanel (1978) found taurodontism to be more frequent in the mandibular second molars. Several attempts have been made to define the term ‘taurodontism’ objectively. These attempts followed Shaw’s (1928) subclassification of taurodont teeth into hyper-, meso- and hypotaurondont types. Keene (1966) developed a taurodontism index by comparing the vertical height of the pulp chamber to the vertical height of the tooth portion containing the pulp. Using this index, Keene (1966) was able to biometrically define Shaw’s hypo-, meso- and hypertaurodont teeth. Keene’s taurodontism index, however, was criticised by Stenvik et al (1972), who felt that a biometric description of taurodontism did not consider the changes in the size of the pulp chamber brought about by physiological aging. Shifman and Chanannel (1978) tried to overcome these shortcomings by using landmarks not exhibiting modifications caused by apposition of reparative dentin or morphological changes of the root anatomy. This method is currently the most common and accepted and was thus used in the present investigation. However, even this ratio can be affected by incomplete root formation or radicular resorption. In addition, root length varies by sex and ethnic
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groups, which may cast some doubt on the credibility of any metric method as a screening tool for taurodontism between different populations and limits the comparability of the results of different studies. In this study, hypotaurodontic molars were significantly more common than mesotaurodonts and hypertaurodonts. Taurodontism appears most frequently as an isolated anomaly. However, its association with several syndromes and abnormalities has also been reported, for instance with cleft lip and palate (Laatikainen and Ranta, 1996), Mohr syndrome (Goldstein and Medina, 1974), tricho-dento-osseous syndrome (Koshiba et al, 1978; Terezhalmy et al, 2001), Down’s syndrome (Bell et al, 1989; Jaspers, 1981), hypophosphatasia (Kjellman et al, 1973), Klinefelter syndrome (Darbyshire et al, 1989; Simpson et al, 2003), ectodermal dysplasia (Gros, 2010), Smith-Magenis syndrome (Tomona et al, 2006), hypodontia (Gomes, 2010; Lai and Seow, 1999), oligodontia (Schalk-van der Weide et al, 1993), Van der Woude syndrome (Nawa, 2008), sex chromosome aberrations (eg, XXX and XYY) (Bell et al, 1989) and amelogenesis imperfecta (Pavlic, 2007). An association with late genes expressed during root formation (ALPL and DLX3 genes) has also been described (Hu and Simmer, 2007). Other conditions reported to be associated with taurodontism are supernumerary teeth (Genc et al, 1999), pulpal calcification (Darwazeh, 1998), ectodermal dysplasia (Bell et al, 1989), osteoporosis (Fuks et al, 1982), thalassaemia major (Hazza’a and Al-Jamal, 2006), dwarfism, dyskeratosis and congenital and epidermolysis bullosa (Terezhalmy et al, 2001).
CONCLUSION In the present study, possible associations of selected oral conditions (cleft lip and palate, pyramidal molars, hypodontia, impaction, amelogenesis imperfecta, pulp calcification and supernumerary teeth) were examined in the subjects with taurodontism. 32.35% of the subjects with taurodontism also had impacted molars, 26.47% (9/34) were associated with hypodontia and 20.6% exhibited pulp calcification. Only one female subject had cleft lip and palate, while none of the subjects with taurodont had AI or any other syndrome. Within the limits of our knowledge, no study to date had examined any association between taurodontism and pyramidal molars. In the present study, 50% of the pa-
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tients having taurodont molars also possessed pyramidal molars on the same or contralateral side, which shows there might be some association between the two. Further studies may be required to establish this association.
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20. Koshiba H, Kimura O, Nakata M, et al. Clinical, genetic, and histologic features of the trichoonychodental (TOD) syndrome. Oral Surg Oral Med Oral Pathol 1978;46:376–385. 21. Laatikainen T, Ranta R. Taurodontism in twins with cleft lip and/or palate. Eur J Oral Sci 1996;104:82–86. 22. Lai PY, Seow WK. A controlled study of the association of various dental anomalies with hypodontia of permanent teeth. Pediatr Dent 1989;1:291–296. 23. Llamas R, Jimenez-Planas A. Taurodontism in premolars. Oral Surg Oral Med Oral Pathol 1993;75:501–505. 24. Mac Donald-Jankowski DS, Li TT. Taurodontism in a young adult Chinese population. Dentomaxillofac Radiol 1993;22:140–144. 25. Madeira MC, Leite HF, Niccoli Filho WD, Simões S. Prevalence of taurodontism in premolars. Oral Surg Oral Med Oral Pathol 1986;61:158–162. 26. Mena CA. Taurodontism. Oral Surg Oral Med Oral Pathol 1971;32:812–823. 27. Nawa H, Oberoi S, Vargervik K. Taurodontism and Van der Woude syndrome. Is there an association? Angle Orthod 2008;78:832–837. 28. Pavlic A, Lukinmaa PL, Nieminen P, Kiukkonen A, Alaluusua S. Severely hypoplastic amelogenesis imperfect with taurodontism. Int J Paediatr Dent 2007;17:259–266. 29. Pickerill HP. Radicular Aberrations. Proc R Soc Med 1909;2:145–161. 30. Sarr M, Toure B, Kane AW, Fall F, Wone MM. [Taurodontism and the pyramidal tooth at the level of the molar. Prevalence in the Senegalese population 15 to 19 years of age]. Odontostomatol Trop 2000;23:31–34. 31. Schalk-van der Weide Y, Steen WH, Bosman F. Taurodontism and length of teeth in patients with oligodontia. J Oral Rehabil 1993;20:401–412. 32. Shafer WG, Hine MK, Levy MB. A textbook of oral patholog, ed 4. W. B. Saunders: Philadelphia, 1999:43. 33. Shaw JC. Taurodont teeth in South African races. J Anat 1928;62:476–498. 34. Shifman A, Buchner A. Taurodontism. Report of sixteen cases in Israel. Oral Surg Oral Med Oral Pathol 1976;41:400–405. 35. Shifman A, Chanannel I. Prevalence of taurodontism found in radiographic dental examination of 1200 young adult Israeli patients. Community Dent Oral Epidemiol 1978;6:200–203. 36. Simpson JL, de la Cruz F, Swerdloff RS. Klinefelter syndrome: expanding the phenotype and identifying new research directions. Genet Med 2003;5:460–468. 37. Stenvik A, Zachrisson BU, Svatun B. Taurodontism and concomitant hypodontia in siblings. Oral Surg Oral Med Oral Pathol 1972;33:841–884. 38. Terezhalmy GT, Riley CK, Moore WS. Clinical images in oral medicine and maxillofacial radiology. Taurodontism. Quintessence Int 2001;32:254–255. 39. Tomona N, Smith ACM, Guadagnini JP, Hart TC. Craniofacial and dental phenotype of Smith-Magenis syndrome. Am J Med Genet 2006;140A:2556–2561. 40. Toure B, Kane AW, Sarr M, Wone MM, Fall F. Prevalence of taurodontism at the level of the molar in the black Senegalese population 15 to 19 years of age. Odontostomatol Trop 2000;23:36–39. 41. Witkop CJ Jr. Manifestations of genetic diseases in the human pulp. Oral Surg Oral Med Oral Pathol 1971;32:278–316.
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APPENDIX Department of Conservative Dentistry and Endodontics, College of Dentistry, Indore DENTAL TREATMENT CONSENT FORM 1. DRUGS AND MEDICATIONS I understand that antibiotics and analgesics and other medications can cause allergic reactions causing redness and swelling of tissues, pain, itching, vomiting and/or anaphylactic shock (severe allergic reaction). 2. CHANGES IN TREATMENT PLAN I understand that during treatment it may be necessary to change or add procedures because of conditions found while working on the teeth that were not discovered during examination, the most common being root canal therapy following routine restorative procedures. 3. TEMPORARY RESTORATIONS I understand that the temporary restorations are only for certain duration of time and need to be replaced. They are to be taken care of during this period and chewing is to be avoided from the concerned side. It is my responsibility to return in the specified time period to get these restoration replaced. 4. FILLINGS (RESTORATIONS) I understand that care must be exercised in chewing on fillings especially during the first 24 hours to avoid breakage. I understand that a more expensive filling that initially diagnosed may be required due to additional decay. I understand that slight sensitivity might occur for few days and is an after effect of a newly placed filing. 5. ENDODONTIC TREATMENT (ROOT CANAL) I realize that the treatment may take several appointments and there is no guarantee that root canal treatment will save my tooth, and that complications can occur from the treatment, and that occasionally metal objects are cemented in the tooth, which does not necessarily affect the success of the treatment. I understand that occasionally additional surgical procedures may be necessary following root canal treatment (apicoectomy). I agree to allow the use of my dental records (study models, radiographs etc.) to be used for educational purposes and research, provided my identity is not disclosed. I understand that dentistry is not an exact science and that, therefore, concerned doctors cannot fully guarantee results. I acknowledge that no guarantee or assurance has been made by anyone regarding the dental treatment which I have requested and authorized. I have had the opportunity to read this form and ask questions. My questions have been answered to my satisfaction. I consent to the proposed treatment. Signature: ________________ Date: ___________
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