Taurodontism in premolars

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    SAMUEL SELTZER, DDS Department of Endodontology School of Dentistry Temple University 3223 North Broad Street Philadelphia, Pennsylvania 19140

    Taurodontism in premolars Rafael Llamaf and Amparo Jimenez-Planas,b Seville, Spain

    DENTAL SCHOOL

    Taurodontism is not a dental anomaly that affects only the molars. In a review of 379 premolars extracted for different pathologic reasons, three cases of taurodontism were found. The three cases were in upper premolars and were studied anatomically and radiographically. The literature was reviewed, as well as the low incidence of the condition in premolars, which is probably related to a genetic condition. Our observations support this fact, as suggested by the study of our cases from a restricted population nucleus, within a district area of the city of Seville, Spain. Among the diagnostic criteria of taurodontism, those established by Shifman and Chanannel are more objective. Finally, our findings support an embryologic origin as a result of a delay in the apical epithelial diaphragm evagination or by interference in the epitheliomesenchymatose induction. (ORAL SURC ORAL MED ORAL PATHOL 1993;75:501-5)

    T aurodontism is a dental anomaly characterized by enlargement of the pulp chamber, which may reach the proximity of the root apex. The term was intro- duced by Sir Arthur Keith in 1913, although Gor- janovic-Kramberger2, in 1908, was the first to de- scribe this type of tooth. He had found it in some 50% of a group of 70,000-year-old pre-Neanderthal fossils, discovered in Kaprina, Croatia. For this reason, some authors have considered taurodontism to be typical of Neanderthal man. It has also been reported in cer- tain hominids such as Sinanthropus and Heidelberg man.4

    This dental anomaly was thought to be absent in modern man. However, an increasing number of works report taurodontism in present-day man in permanent dentition,* 6 deciduous dentition,7-9 or both,0-4 and both associated and not associated with determinate pathologic conditions.

    Taurodontism may be associated with certain di.s-

    Associate Professor of Pathology and Dental Therapeutics bProfessor of Odontological Materials. Copyright 1993 by Mosby-Year Book, Inc. 0030-4220/93/$1.00 +.I0 7/15/42861

    eases such as hypophosphatasia,t5-1* or alterations of the sexual chromosomes, such as Klinefelters syn- drome,8, 19-23 trisomy 21, or Downs syndrome,24, 25 X-chromosome aneuploid syndrome,26-28 XXX-chro- mosome syndrome,29 associated with XYY syn- drome,30 or with ectodermal defects such as heredi- tary ectodermal dysplasia,3 tricho-onycho-dental syndrome,32 orofacial digital II syndrome or Mohr syndrome,33 tricho-dento-osseous syndrome,34, 35 amelo-onycho-hypohidrotic syndrome,36 and hypo- hidrotic ectodermal dysplasia linked to the X-chro- mosome.37

    A certain familial tendency has been reported in the presentation of taurodontism.*, 38 Fischer38 described a case of 12 members of the same family having tau- rodont teeth. This was probably related with an auto- somal dominant gene of variable expression.

    This anomaly has been reported to be associated with microcephalic dwarfism39 and external resorp- tion-microcephalic dwarfism,40 with other dental anomalies such as agenesis or fusions,14 microdontias and dens invaginatus,41, 42 amelogenesis imperfec- ta,14, 43-47 and with dermatologic diseases.48

    In 1928, Shaw3 classified taurodontism into hypo-,

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  • 502 L/anlas ard Jimrnez-Plana,!

    Fig. 1. Measurements oftaurudont teeth according to the criteria of Shifman and Chanannel.

    Fig. 2. Taurodont upper premolars

    meso-, and hypertaurodontism, on the basis of the apical displacement of the pulp chamber flo0r.j This arbitrary and subjective classification has led to some teeth being considered taurodont that were not.

    In 1977, Feichtinger and Rossiwall7 considered that to define taurodontism, the distance from the furcation to the amelocementary joint should be greater than the cervico-occlusal distance.

    Later, in 1978, Shifman and Chanannel estab- lished more objective criteria on the basis of deter- mined measurements of the tooth (Fig. I). A tooth is taurodont when the distance from the lowest point ot the pulp chamber roof (A) to the highest point of the floor (B), divided by the distance from A to the root apex (C), is equal to or greater than 0.2 mm, and when the distance from B to the amelocementary joint ii)) is greater than 2.5 mm.

    Fig. 3. K;ldiogr,iph! 01 taurodont upper prcmoiars. C;IK I shoas addition:illc internal resorption 01 palatine root.

    Taurodontixm ih a dental anomaly Ihat 14 dlagnoscd most often in molars and occasionallq in premolars. This was contirmed in the Neanderthal teeth found in Kaprina after the radiographic study carried out 1,) Kallay: O. j1 There is an increasing number of work\ that refer to the incidence of taurodontism in prcmo- jars in modern man.13. 4). 52-i)

    To consider premolars to be taurodont. they must have the following anatomical characteristics: (I ) lower cervical constriction: (2) a broad, prism-shaped root with cervical and apical thickening; (3) a dilated. bifurcated, and slightlq concave root: and (41 enlarge- ment of the pulp chamber with root bifurc:rtion.

    MATERIAL AND METHODS

    A total of 379 premolars was reviewed. These had been extracted over a period of 8 years in one district of the city 01 Seville, Spain. Seventy-siu of these (20.06%) were first upper premolars, 139 (36.67%) were second upper premolars. I I7 ( 30.87G:-p) were first lower premolars. and 47 ( 12.40% ) were second lower premolars. All patients were white. The teeth were extracted for caries, periodontal disease. or orthodon- tic reasons.

    411 were studied anatomicall) and radivgraphi- tally. following the criteria of Madeira ct al. and Shifman and (hanann& mentioned :~bocc

    RESULTS

    Of the 379 teeth studied, only three upper prernu- lars (0.79%-) presented anatomic (Fig. 2) and radio- graphic (Fig. 3) features that corresponded to tauro- dont teeth. All teeth fulfilled the anatomic criteria to be considered ;I> taurodontic.5 loner cervical con- \triction, broad root with slight cervical thickening. and a wide pulp chamber that was bifurcated in the

  • ORAl. St;RGtRY OR \I MLDICIYE ORAL PlTFIOlOG\ Volume 75. Number 5

    Llamas and Jimenez- Plunas 503

    apical third into two ducts. The radiography of the teeth studied was evaluated according to the criteria of Shifman and Chanannel.

    Case I : Age and sex were unknown. Extraction was for caries. The tooth showed caries that affected the occlusal and interproximal surfaces. The anatomy showed a wide pulp chamber that bifurcated in the apical third into two ducts. Both of these had acces- sory ducts, and the palatine showed internal resorp- tion. The data obtained from radiographic evaluation were:AtoB=Smm;AtoC= 13mm;AtoB/Ato C = 0.38 mm; B to D = 5 mm.

    Case 2: Age and sex were unknown. Extraction was for caries. The tooth showed caries affecting the interproximal surface. The data obtained from radio- graphic evaluation were: A to B = 9 mm; A to C = 16 mm; A to B/A to C = 0.56 mm; B to D = 10 mm.

    Case 3: This was a 16-year-old girl. The extraction had been made for orthodontic reasons. Another two premolars from the same patient did not show alter- ations. Calcifications were identified inside the p~,lp chamber. The data obtained from radiographic eval- uation were: A to B = 6 mm; A to C = 14 mm; A to B/A to C = 0.42 mm; B to D = 6 mm.

    DISCUSSION

    Taurodontism is an anomaly of multiroot teeth, sometimes bilateral53 I33 s7, 6o and sometimes multi- ple.3.h0 It is characterized by enlargement of the apical portion of the pulp chamber.

    The incidence of taurodontism is very variable, de- pending on the different series and groups studied. It is lower than 1%~ in modern man and 3% in primitive man and in Eskimos and American Indians6 The in- cidence of this anomaly is evident in an increasing number of determinate ethnic groups, such as those reported by Mjiir,(j in Eskimos, Aleutians, Europe- ans, Israelis. and black and white Americans. In a survey carried out in the region of Navarre in Spain, 68 teeth were studied. These were first, second, and third taurodont molars from 26 patients, which affected between one and six teeth per person.60 In another Spanish series from Granada University, 48 teeth were studied, which comprised definitive and deciduous taurodont molars.14

    Some authors consider this dental anomaly to be a retrograde or atavistic feature because its incidence is decreasing..

    The teeth most frequently affected are the mo- lars.6, 13. 25. 65-67 These are most easily diagnosed by radiographic study. In some series, up to 43.2% can be reached. The premolars present a lower incidence, and the lower ones are more commonly affected than

    the upper ones. jg The anatomic characteristics of the upper premolars make in situ diagnosis difficult in routine radiographic studies.

    The incidence of taurodontism in premolars is low. The works that refer to it are scarce,lj, i2-59 and those that consider the upper premolars are fewer still. Shifman and Buchner57 report a bilateral case in the second upper premolars. A study by Madeira et a1.s9 of 3,449 lower premolars found seven taurodont first premolars and four second premolars but none among I ,010 upper premolars.

    The observation of taurodont upper premolars in such a small series (0.72%) as ours, taken from a re- stricted population nucleus from a district area of Seville, Spain, leads to the thought that taurodontism, observed in certain ethnic groups, of different time periods, may have a certain genetic or hereditary na- ture, 6s 3 68 as Fischer3* reported in 12 members of the sa