Taurodontism in dental genetics

The relevance of taurodontism in forensic dental age estimation

Taurodontism is a dental morphological anomaly characterized by enlarged pulp cavities repositioned towards the apical region of the tooth, coupled with shortened root structures. Molars are commonly affected by this alteration. Certain populations exhibit up to 48% prevalences for this dental alteration, underscoring its significance in dental age estimation (DAE). In the field of DAE, an individual's chronological age is inferred from specific dental features, frequently employed within the forensic context. The effect of taurodontism on the features of DAE is an unanswered issue. The influence of taurodontism on eruption, mineralization, radiographic visibility of root canals, and radiographic visibility of the periodontal ligament space in mandibular third molars- some of the established criteria for DAE as examples-is currently not systematically examined. Some common staging scales for the dental features of DAE cannot technically be applied to taurodontic teeth. Additionally, given the association of taurodontism with syndromes affecting tooth development, caution is warranted in age assessment procedures. Notably, taurodontic teeth may serve as indicators of syndromes influencing skeletal development, further emphasizing the relevance of taurodontism in forensic age assessment. Presumably taurodontic teeth were included in reference data to some extent due to their partially high prevalence in the past, whereby the influence of taurodontism has been statistically absorbed within the overall spread of the features. Future studies should compare the temporal course of these tooth characteristics in affected and unaffected teeth. Subsequent initiatives should focus on raising awareness among forensic dentists regarding taurodontism, necessitating in-depth exploration of the subject.

Genetic Variants in KCTD1 Are Associated with Isolated Dental Anomalies

KCTD1 plays crucial roles in regulating both the SHH and WNT/β-catenin signaling pathways, which are essential for tooth development. The objective of this study was to investigate if genetic variants in KCTD1 might also be associated with isolated dental anomalies. We clinically and radiographically investigated 362 patients affected with isolated dental anomalies. Whole exome sequencing identified two unrelated families with rare (p.Arg241Gln) or novel (p.Pro243Ser) variants in KCTD1. The variants segregated with the dental anomalies in all nine patients from the two families. Clinical findings of the patients included taurodontism, unseparated roots, long roots, tooth agenesis, a supernumerary tooth, torus palatinus, and torus mandibularis. The role of Kctd1 in root development is supported by our immunohistochemical study showing high expression of Kctd1 in Hertwig epithelial root sheath. The KCTD1 variants in our patients are the first variants found to be located in the C-terminal domain, which might disrupt protein-protein interactions and/or SUMOylation and subsequently result in aberrant WNT-SHH-BMP signaling and isolated dental anomalies. Functional studies on the p.Arg241Gln variant are consistent with an impact on β-catenin levels and canonical WNT signaling. This is the first report of the association of KCTD1 variants and isolated dental anomalies.

CBCT imaging and root canal treatment for taurodontism in mandibular second molar - A case report and literature review

The mandibular second molar exhibits a wide range of intricate root canal variations, which can present challenges and difficulties in achieving successful root canal treatment. This report focuses on two specific cases involving a root canal variation in a typical taurodontism of the mandibular second molar. To provide a comprehensive analysis and illustration of the anatomical structure of intraoral taurodontism and the important considerations for root canal treatment, we utilized advanced imaging techniques such as cone beam computed tomography (CBCT) and a dental microscope. By combining these tools, we were able to gain a deeper understanding of the complex root canal system and make informed decisions during the treatment process.

Prevalence of Taurodontism in Contemporary and Historical Populations from Radom: A Biometric Analysis of Radiological Data

Taurodontism is a morphological anomaly of multirooted molars characterized by apical displacement of the pulp chamber, shortened roots, and the absence of constriction at the dentoenamel junction. It can negatively impact the outcome of dental treatment plans. This study aimed to compare the prevalence of taurodontism among contemporary and historical populations from Radom, Poland. Five hundred eighty-two panoramic radiographs of contemporary patients and 600 radiographs of historical individuals were analyzed using the Shifman and Chanannel index. Group differences were determined with Pearson's chi-square tests according to sex, site, tooth group, and historical period. The study also evaluated the degree of severity of taurodontism in relation to dental groups, gender, and the periods from which contemporary patients as well as historical individuals originated. In the contemporary population, taurodontism was observed in 34% of individuals. In the historical data, the highest prevalence of taurodontism (31%) was observed among individuals from the 18th and 19th centuries, while earlier periods exhibited considerably lower prevalence rates. Across contemporary and historical populations, the maxillary molars were the most commonly affected teeth. Hypotaurodontism was the most prevalent form of taurodontism. The prevalence of taurodontism has gradually increased from the 11th century to the current day. The results of the research are of great importance for the clinician in terms of planning comprehensive dental treatment.

Co-Occurrence of Taurodontism in Nonsyndromic Cleft Lip and Palate Patients in Subset of Indian Population: A Case-Control Study Using CBCT

The present study aimed to assess the co-occurrence of taurodontism in nonsyndromic cleft lip and palate (NSCLP) patients in a subset of Indian population using cone beam computed tomography (CBCT).

The study was a retrospective case-control kinds assessing 1500 CBCT scans over a period of 2 years; 67 scans out of 1500 showed cleft lip and palate (CLP). After fulfilling the inclusion and exclusion criteria, 38 subjects out of 67 comprised the case group; 80 randomly selected subjects constituted the control group. The first and second permanent molars in both the arches (8 teeth) of each subject were assessed for the presence and severity of taurodontism using the objective criteria. Statistical analysis was done using the χ2 test. Inter and intraobserver agreement was evaluated by Kappa statistics.

71.05% subjects showed taurodontism in case group, while 45% subjects showed its presence in control group; results being significant for both the groups. However, the comparison of number of teeth with taurodontism in the 2 groups came out to be statistically insignificant. Also no significant association of taurodontism was seen with gender or the different types of cleft (P = .437). Hypotaurodontism was the most prevalent type.

There was a higher prevalence of taurodontism in both groups which had been underestimated in the previous studies. This emphasizes the significance of the use of CBCT in detection of dental anomalies which would otherwise go undetected.

Non-syndromic generalised hypotaurodontism in a case of Stage III Grade C periodontitis

Taurodontism is a rare dental morphological anomaly characterised by an unusual increase in the vertical height of the pulpal chamber along with an apical displacement of the pulpal floor. The tooth lack constriction at the cementoenamel junction is mimicking a bull tooth. Taurodontism is usually observed as an isolated tooth aberration. However, it can also be associated with specific syndromes such as Down's syndrome, amelogenesis imperfecta, Klinefelter syndrome, Tricho-Dento-Osseous syndrome, Mohr syndrome, Prader-Labhart-Willi syndrome, Ellis van Creveld syndrome and Lowe syndrome. Periodontitis is characterised by microbially associated, host-mediated inflammation that results in loss of periodontal attachment. This case report describes a rare case of non-syndromic generalised taurodontism in a male patient with Stage III Grade C periodontitis. The patient was promptly given periodontal care by root planing and Kirkland flap surgery.

Novel ITGB6 variants cause hypoplastic-hypomineralized amelogenesis imperfecta and taurodontism: characterization of tooth phenotype and review of literature

OBJECTIVES

To characterize phenotype and genotype of amelogenesis imperfecta (AI) in a Thai patient, and review of literature.

MATERIALS AND METHODS

Variants were identified using trio-exome and Sanger sequencing. The ITGB6 protein level in patient's gingival cells was measured. The patient's deciduous first molar was investigated for surface roughness, mineral density, microhardness, mineral composition, and ultrastructure.

RESULTS

The patient exhibited hypoplastic-hypomineralized AI, taurodontism, and periodontal inflammation. Exome sequencing identified the novel compound heterozygous ITGB6 mutation, a nonsense c.625 G > T, p.(Gly209*) inherited from mother and a splicing c.1661-3 C > G from father, indicating AI type IH. The ITGB6 level in patient cells was significantly reduced, compared with controls. Analyses of a patient's tooth showed a significant increase in roughness while mineral density of enamel and microhardness of enamel and dentin were significantly reduced. In dentin, carbon was significantly decreased while calcium, phosphorus, and oxygen levels were significantly increased. Severely collapsed enamel rods and a gap in dentinoenamel junction were observed. Of six affected families and eight ITGB6 variants that have been reported, our patient was the only one with taurodontism.

CONCLUSION

We report the hypoplasia/hypomineralization/taurodontism AI patient with disturbed tooth characteristics associated with the novel ITGB6 variants and reduced ITGB6 expression, expanding genotype, phenotype, and understanding of autosomal recessive AI.

Frequency of occurrence of taurodontism in the historical population of Radom (11th-19th centuries)

OBJECTIVE

The aim of the work was to trace possible changes in the frequency of taurodontism in individuals who inhabited historical Radom from the early Middle Ages to modern periods.

DESIGN

The research was based on the analysis of X-ray images of 640 molars of individuals from the 11th/12th c. (n = 120), 14th/17th c. (n = 76), and 18th/19th c. (n = 444). Radiological images were made with the use of a portable X-ray machine, and the results were biometrically analysed using the Shiffman and Chanannel index.

RESULTS

The highest frequency of taurodontism was observed in the 18th/19th c. (31 %, 138/444). In the 11th/12th and 14th/17th centuries, this percentage was significantly lower (22 %, 26/120 vs. 16 %, 12/76). In subsequent chronological periods, no statistically significant differences between sexes in the occurrence of taurodontism were observed. The highest number of taurodontal teeth was observed among the second and first upper molars (73 % and 52 %, respectively), and the lowest number was observed among the first and second lower molars (16 % and 23 %, respectively). In all historical periods, hypotaurodont forms were most often observed.

CONCLUSIONS

Variations in the frequency of taurodontism may result from many reasons, for example environmental factors. However, it cannot be ruled out that the observed differences result from the increased migration of people to Radom in the 18th/19th century.

Craniofacial and dental features of Axenfeld-Rieger syndrome patients with PITX2 mutations

We aimed to characterize the genetic basis and craniofacial and dental features of Finnish patients with Axenfeld-Rieger syndrome (ARS). Mutational analyses of seven patients in five families were performed by sequencing or comparative genomic hybridization. Phenotypic analysis was based on both clinical and radiographic examinations, as well as on medical data. Lateral cephalometric radiographs of five patients were analysed using Viewbox 3.1-Cephalometric Software. The cephalometric values were compared to Finnish population-standard values of the same age and gender. Two frameshift mutations and three whole gene deletions were detected in five families. Class III skeletal relationship with retrognathic maxilla and mildly retrognathic mandible were detected in all five patients studied. Significant differences compared with the control values were in SNA (P = .0014), ANB (P = .0043) and SNB angles (P = .013). Five patients had anterior crossbite. Six patients showed tooth agenesis. The average number of missing teeth (third molars excluded) was 9 (range 0-15). The tooth agenesis rate was 52% in maxilla and 26% in mandible. Maxillary central and lateral permanent incisors were most often missing (rate 71% equally) while no one lacked canines or first molars in mandible. Two patients had a supernumerary mandibular permanent incisor. Six patients had either taurodontic and/or single-rooted molars. Our results suggest that class III skeletal relationship with maxillary and mandibular retrognathism, anterior crossbite, maxillary incisor agenesis and taurodontic, even pyramidal, roots are common determinants of ARS caused by PITX2 mutations.

BDJ Open 2021 - our most successful year to date

This paper aims to provide an update on the previous version published towards the end of last year, titled 'BDJ Open (2019-2020) and the advantages of open access publishing'. In this paper, we will highlight articles published throughout 2021, in order to focus on which areas authors felt were important to publish open access and also which areas have been expanded upon in the journal. Furthermore, this paper will examine how open access publishing in BDJ Open has enabled the continuous process of hypothesis testing to be shared more widely, as well as how publishing protocols and early results open access gives strength to that by allowing earlier opportunity for comment by other researchers, both through the peer review process and through further correspondence to authors directly and to the journal editors who publish their work.

Provides an update on the previous 2019-2020 paper by examining articles published in BDJ Open in 2021, to highlight which areas researchers felt were important to publish open access.

Highlights the advantages of open access publishing to authors, readers and the scientific community, particularly in light of the ongoing COVID-19 pandemic.

Explores how open access publishing in BDJ Open has enabled the continuous process of hypothesis testing to be shared more widely, allowing earlier opportunity for comment by other researchers.

The Human Genetics of Dental Anomalies

The development of tooth is a highly complex procedure and mastered by specific genetic programs. Genetic alterations, environmental factors, and developmental timing can disturb the execution of these programs, and result in various dental anomalies like hypodontia/oligodontia, and supernumerary teeth, which are commonly seen in our clinical practice. Advances in molecular research enabled the identification of various genes involved in the pathogenesis of dental anomalies. In the near future, it will help provide a more accurate diagnosis and biological-based treatment for these anomalies. In this article, we present the molecular phenomenon of tooth development and the genetics of various dental anomalies.

Comparative dental study between Homo antecessor and Chinese Homo erectus: Nonmetric features and geometric morphometrics

The Chinese Middle Pleistocene fossils from Hexian, Xichuan, Yiyuan, and Zhoukoudian have been generally classified as Homo erectus s.s. These hominins share some primitive features with other Homo specimens, but they also display unique cranial and dental traits. Thus, the Chinese Middle Pleistocene hominins share with other European and Asian hominin populations the so-called 'Eurasian dental pattern'. The late Early Pleistocene hominins from Gran Dolina-TD6.2 (Spain), representing the species Homo antecessor, also exhibit the Eurasian dental pattern, which may suggest common roots. To assess phylogenetic affinities of these two taxa, we evaluated and compared nonmetric and metric dental features and interpreted morphological differences within a comparative hominin framework. We determined that the robust roots of the molars, the shelf-like protostylid, the dendrite-like pattern of the enamel-dentine junction surface of the upper fourth premolars and molars, the strongly folded dentine of the labial surface of the upper incisors, and the rare occurrence of a mid-trigonid crest in the lower molars, are all characteristic of Chinese H. erectus. With regard to H. antecessor, we observed the consistent expression of a continuous mid-trigonid crest, the absence of a cingulum in the upper canines, a complex root pattern of the lower premolars, and a rhomboidal occlusal contour and occlusal polygon and protrusion in the external outline of a large a bulging hypocone in the first and second upper molars. Using two-dimensional geometric morphometrics, we further demonstrated that H. antecessor falls outside the range of variation of Chinese H. erectus for occlusal crown outline shape, the orientation of occlusal grooves, and relative locations of anterior and posterior foveae in the P⁴s, P₃s, M¹s, M²s, and M₂s. Given their geographic and temporal separation, the differences between these two species suggest their divergence occurred at some point in the Early Pleistocene, and thereafter they followed different evolutionary paths.