# Taurodontism--Prevalence, Extent, and Clinical Challenge in Ashkelon, Israel--A Retrospective Study
## 1 Introduction  
Taurodontism is an anomaly of tooth shape that most often affects molars in deciduous as well as permanent dentition [1; 2; 3]. It was found in the ancient populations of Homo sapiens neanderthalensis and was assumed to be associated with thin enamel [4; 5]. As the assumption that taurodontism was prehistorically advantageous for people to enable heavy masticatory habits was not proven, other external factors can be attributed to the anomaly [3; 6]. It occurs in both the maxilla and mandible and is more commonly seen in molar teeth, unilaterally or bilaterally [7]. This dental anomaly is characterized by an enlarged apically displaced pulp chamber, a proportionately shortened root, and an enlarged pulp chamber in the affected dentition and apically displaced function areas. The bifurcation may be only a few millimeters above the apices of the roots [7]. Additionally, the teeth did not present the usual constriction at the cementoenamel junction observed in molars with a normal pulp chamber [8]. The pathogenesis of taurodontism is attributed to a disturbance in [PERSON]'s epithelial root sheath (HESR), which forms the initial outline for the root's morphology. A delay or failure in root invagination at the truncation region of themultiple roots of teeth results in the disturbance of a formation of the pulp chamber, which leads to several morphological aberrations, including tautodontism [3; 9]. This vertical elongation of the pulp chamber of the teeth below the CEJ [3] may be a marker of orofacial disorders and has been reported to occur either as an isolated disorder or associated with dental anomalies and developmental syndromes [8]. Associations have been reported between tautodontism and microdontia, dens invisimatus, amelogenesis imperfeta, and dermatological diseases [10]. It has also been linked to the X-chromosome polyploidy, such as 47 XXX, 48 XXXX11, and 47 XXY evident within the Finnish population [11; 12]. An increasing trend of severity was observed with each additional X-chromosome [13; 14]. In addition, Down syndrome patients have presented a greater frequency of tautodontism than in the presumed normal population [15].  
Diagnosis of tautodontism has been mainly based on radiographic assessments, as the external crown morphology was within normal configurations [16]. Taurodontism was initially detected by periapical X rays and in panoramic radiographs [17; 18]. Literature displays a variability of prevalence from less than 0.1% to 48% [19; 20; 21]. This diversity basically results from a lack of uniformity either in methodology or classification performed in different studies [22]. Taurodontism is classified according to its extent from the mildest (hypotaurodontism) through the moderate (mesotaurodontism) to the most severe manifestation (hypertaurodontism) [14]. However, different classifications of taurodontism were not always used by some of the studies that reported only on mesotaurodontism and hypertaurodontism, while ignoring hypotaurodontism and a highly affected comparison of prevalence between the population [21].  
Taurodontism has an impact on the various types of treatment modalities: it complicates endodontic treatments, reduces the root canal surface area available for post anchorage, and jeopardizes orthodontic treatment due to root resorption vulnerability. Thus, the prevalence of taurodontism is important for the dental disciplines of endodontics, orthodontics, prosthodonics [3; 14; 21], and periodontitis.  
The aim of this study is to evaluate the prevalence of taurodontism amongst Israelis in one medical center using measurements from panoramic radiographs in order to discuss its implications for general dental practice treatment modalities.