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PloS One 2018Tooth crown tissue proportions and enamel thickness distribution are considered reliable characters for inferring taxonomic identity, phylogenetic relationships, dietary...
Tooth crown tissue proportions and enamel thickness distribution are considered reliable characters for inferring taxonomic identity, phylogenetic relationships, dietary and behavioural adaptations in fossil and extant hominids. While most Pleistocene hominins display variations from thick to hyper-thick enamel, Neanderthals exhibit relatively thinner. However, the chronological and geographical origin for the appearance of this typical Neanderthal condition is still unknown. The European late Early Pleistocene species Homo antecessor (Gran Dolina-TD6 site, Sierra de Atapuerca) represents an opportunity to investigate the appearance of the thin condition in the fossil record. In this study, we aim to test the hypothesis if H. antecessor molars approximates the Neanderthal condition for tissue proportions and enamel thickness. To do so, for the first time we characterised the molar inner structural organization in this Early Pleistocene hominin taxon (n = 17) and compared it to extinct and extant populations of the genus Homo from African, Asian and European origin (n = 355). The comparative sample includes maxillary and mandibular molars belonging to H. erectus, East and North African Homo, European Middle Pleistocene Homo, Neanderthals, and fossil and extant H. sapiens. We used high-resolution images to investigate the endostructural configuration of TD6 molars (tissue proportions, enamel thickness and distribution). TD6 permanent molars tend to exhibit on average thick absolute and relative enamel in 2D and 3D estimates, both in the complete crown and the lateral enamel. This condition is shared with the majority of extinct and extant hominin sample, except for Neanderthals and some isolated specimens. However, while the total crown percentage of dentine in TD6 globally resembles the low modern values, the lateral crown percentage of dentine tends to be much higher, closer to the Neanderthal signal. Similarly, the H. antecessor molar enamel distribution maps reveal a relative distribution pattern that is more similar to the Neanderthal condition (with the thickest enamel more spread at the periphery of the occlusal basin) rather than that of other fossil specimens and modern humans (with thicker cuspal enamel). Future studies on European Middle Pleistocene populations will provide more insights into the evolutionary trajectory of the typical Neanderthal dental structural organization.
Topics: Animals; Biological Evolution; Crowns; Dental Enamel; Fossils; Humans; Molar; Neanderthals; Paleodontology; Phylogeny; Spain; Tooth Crown
PubMed: 30281589
DOI: 10.1371/journal.pone.0203334 -
BMC Oral Health Feb 2020In this study, we conducted a quantitative analysis of the clinical parameters of crown and gingival morphology (CGM) of the maxillary anterior teeth (MAT). We also...
BACKGROUND
In this study, we conducted a quantitative analysis of the clinical parameters of crown and gingival morphology (CGM) of the maxillary anterior teeth (MAT). We also analyzed the correlation of these parameters with periodontal biotype (PB), with a view to providing objective standards for PB diagnosis.
METHODS
The three-dimensional (3D) maxillary digital models of 56 individuals were obtained using an intra-oral scanner. The following parameters were measured with the SpaceClaim software: gingival angle (GA), papilla width (PW), papilla height (PH), crown length (CL), crown width (CW), crown width/crown length ratio (CW/CL), bucco-lingual width of the crown (BLW), contact surface width (CSW), and contact surface height/crown length ratio (CS/CL). The PB were determined based on the transparency of the periodontal probe through the gingival sulcus. Independent factors influencing PB were analyzed by logistic regression, and the optimal cutoff values for the independent influencing factors were analyzed using receiver operating characteristic curves (ROC curves).
RESULTS
There was no significant difference in the parameters of CGM of the MAT at the left and right sides. The thick biotype accounted for 69.6%, and the parameters of GA, PW, PH, CW, CW/CL and CS/CL were significantly correlated with PB (P ≤ 0.2). GA (odds ratio (OR) = 1.206) and PW (OR = 5.048) were identified as independent predictive factors of PB, with areas under the ROC curve (AUC) of 0.807 and 0.881, respectively, and optimal cutoff values of 95.95° and 10.01 mm, respectively.
CONCLUSION
The CGMs of the MAT at the left and right side are symmetrical. The thin biotype accounts for a small proportion, and GA and PW are independent influencing factors of PB. GA of 95.95° and PW of 10.01 mm are the optimal cutoff values for categorization of individuals as thick biotype. This indicates that when the GA and PW of the right maxillary central incisor are G ≥ 95.95° and ≥ 10.01 mm, respectively, there is a higher probability that these individuals will be categorized as thick biotype.
Topics: Crowns; Gingiva; Humans; Incisor; Maxilla; Periodontics; Tooth Crown
PubMed: 32075626
DOI: 10.1186/s12903-020-1040-x -
Journal of Forensic Sciences Sep 2022Cone-beam computed tomography (CBCT) enables the assessment of regressive morphological changes in teeth, which can be used to predict chronological age (CA) in adults....
Cone-beam computed tomography (CBCT) enables the assessment of regressive morphological changes in teeth, which can be used to predict chronological age (CA) in adults. As each tooth region is known to have different correlations with CA, this study aimed to segment and quantify the sectional volumes of the tooth crown and root from CBCT scans to test their correlations with the chronological age (CA). Seventy-five CBCT scans from individuals with age between 20 and 60 years were collected retrospectively from an existing database. A total of 192 intact maxillary anterior teeth fulfilled the eligibility criteria. The upper tooth volume ratio (UTVR), lower tooth volume ratio (LTVR), and sex were used as predictor variables. The UTVR and LTVR parameters were both found to be differently correlated to CA and independent from each other. Regression models were derived from each tooth, with the highest R being the maxillary lateral incisor (R = 0.67). Additional single predictor models using each ratio were capable of reliably predicting the CA. The segmentation approach in volumetric adult dental age estimation proved to be beneficial in enhancing the reliability of the regression model.
Topics: Adult; Cone-Beam Computed Tomography; Crowns; Humans; Incisor; Middle Aged; Reproducibility of Results; Retrospective Studies; Tooth Crown; Young Adult
PubMed: 35819122
DOI: 10.1111/1556-4029.15094 -
The Angle Orthodontist Apr 2004This systematic review addresses the question whether prematurity results in alteration of palatal morphology, dental occlusion, tooth-crown dimensions, and tooth... (Review)
Review
This systematic review addresses the question whether prematurity results in alteration of palatal morphology, dental occlusion, tooth-crown dimensions, and tooth maturation. A literature survey from the PubMed database covering the period from January 1966 to November 2002 used the Medical Subject Headings terms "infant, premature," and "infant, low birth weight" in combination with "jaws," "dental physiology," "dentition," and "tooth abnormalities." Controlled studies written in English and with definitions of premature birth according to the World Health Organization were selected. Two reviewers selected and extracted the data independently and also assessed the quality of the studies. The search strategy resulted in 113 articles, of which 13 met the inclusion criteria. Scientific evidence was found for altered palatal morphology in the short term among the premature children, and oral intubation was a contributing factor to the alterations. If corrected age was considered for the premature children, no delay in dental development and eruption was found compared with normally born children. Thus, the early birth of premature children must be taken in account when planning for orthodontic treatment. Because of the contradictory results and lack of longitudinal studies, the scientific evidence was too weak to answer the questions whether premature birth causes permanent alteration of palatal morphology, alteration of dental occlusion, and altered tooth-crown dimensions. To answer these questions and obtain reliable scientific evidence whether premature children are at risk for malocclusions from possible alterations of palatal morphology such as asymmetry and high arched palates, further well-designed controlled studies as well as longitudinal studies are needed.
Topics: Dental Research; Humans; Infant, Newborn; Infant, Premature; Intubation, Intratracheal; Malocclusion; Odontometry; Palate, Hard; Tooth Crown; Tooth Eruption
PubMed: 15132456
DOI: 10.1043/0003-3219(2004)074<0269:ASROTC>2.0.CO;2 -
PloS One 2015Shark and ray (elasmobranch) dentitions are well known for their multiple generations of teeth, with isolated teeth being common in the fossil record. However, how the...
Shark and ray (elasmobranch) dentitions are well known for their multiple generations of teeth, with isolated teeth being common in the fossil record. However, how the diverse dentitions characteristic of elasmobranchs form is still poorly understood. Data on the development and maintenance of the dental patterning in this major vertebrate group will allow comparisons to other morphologically diverse taxa, including the bony fishes, in order to identify shared pattern characters for the vertebrate dentition as a whole. Data is especially lacking from the Batoidea (skates and rays), hence our objective is to compile data on embryonic and adult batoid tooth development contributing to ordering of the dentition, from cleared and stained specimens and micro-CT scans, with 3D rendered models. We selected species (adult and embryonic) spanning phylogenetically significant batoid clades, such that our observations may raise questions about relationships within the batoids, particularly with respect to current molecular-based analyses. We include developmental data from embryos of recent model organisms Leucoraja erinacea and Raja clavata to evaluate the earliest establishment of the dentition. Characters of the batoid dentition investigated include alternate addition of teeth as offset successional tooth rows (versus single separate files), presence of a symphyseal initiator region (symphyseal tooth present, or absent, but with two parasymphyseal teeth) and a restriction to tooth addition along each jaw reducing the number of tooth families, relative to addition of successor teeth within each family. Our ultimate aim is to understand the shared characters of the batoids, and whether or not these dental characters are shared more broadly within elasmobranchs, by comparing these to dentitions in shark outgroups. These developmental morphological analyses will provide a solid basis to better understand dental evolution in these important vertebrate groups as well as the general plesiomorphic vertebrate dental condition.
Topics: Animals; Biological Evolution; Dentition; Fossils; Models, Anatomic; Phylogeny; Sharks; Skates, Fish; Species Specificity; Tooth; Tooth Crown; Tooth Root; Vertebrates
PubMed: 25874547
DOI: 10.1371/journal.pone.0122553 -
PloS One 2024Morphological variation in modern human dentition is still an open field of study. The understanding of dental shape and metrics is relevant for the advancement of human...
Morphological variation in modern human dentition is still an open field of study. The understanding of dental shape and metrics is relevant for the advancement of human biology and evolution and is thus of interest in the fields of dental anthropology, as well as human anatomy and medicine. Of concern is also the variation of the inner aspects of the crown which can be investigated using the tools and methods of virtual anthropology. In this study, we explored inter- and intra-population morphometric variation of modern humans' upper third and fourth premolars (P3s and P4s, respectively) considering both the inner and outer aspects of the crown, and discrete traits. We worked by means of geometric morphometrics on 3D image data from a geographically balanced sample of human populations from five continents, to analyse the shape of the dentinal crown, and the crown outline in 78 P3s and 76 P4s from 85 individuals. For the study of dental traits, we referred to the Arizona State University Dental Anthropology System integrated with more recent classification systems. The 3D shape variation of upper premolar crowns varied between short and mesio-distally broad, and tall and mesio-distally narrow. The observed shape variation was independent from the geographical origin of the populations, and resulted in extensive overlap. We noted a high pairwise correlation (r1 = 0.83) between upper P3s and P4s. We did not find any significant geographic differences in the analysed non-metric traits. Our outcomes thus suggest that geographical provenance does not play a determinant role in the shaping of the dental crown, whose genesis is under strict genetic control.
Topics: Animals; Humans; Bicuspid; Anthropology, Physical; Hominidae; Anthropology; Tooth Crown
PubMed: 38593117
DOI: 10.1371/journal.pone.0301482 -
Hua Xi Kou Qiang Yi Xue Za Zhi = Huaxi... Dec 2016We measured and analyzed the angle between the longitudinal axis of incisor crown and tooth to provide a reference for orthodontists for selecting orthodontic methods...
OBJECTIVE
We measured and analyzed the angle between the longitudinal axis of incisor crown and tooth to provide a reference for orthodontists for selecting orthodontic methods and evaluating treatment results.
METHODS
A total of 120 participants were included according to the criteria of Andrews' six keys, and cephalometric radiograph under the instructions of modified natural head position acquirement method was performed. The angles of maxillary incisor crown longitudinal axis, tooth longitudinal axis, occlusion plane (OP), and true vertical (TV) plane were measured, as well as mandibular incisors.
RESULTS
As for maxillary incisors, the angle between crown longitudinal axis and TV plane, OP, and tooth longitudinal axis were 11.72°±4.71°, 73.29°±5.69°, and 20.04°±3.71°, respectively. For mandibular incisors, the angle between crown longitudinal axis and TV plane, OP, and tooth longitudinal axis were 16.03°±5.40°, 81.76°±4.81°, and 14.82°±4.01°, respectively. For the maxillary incisor, the angles between crown longitudinal axis and tooth longitudinal axis were mainly within 15° to 25°, whereas those for mandibular incisors were within 10° to 20°.
CONCLUSIONS
The longitudinal axis inclinations of the maxillary and mandibular incisor crown and of the incisor tooth need to be considered when cephalometric radiographs are used for treatment planning or for evaluating the treatment result.
Topics: Cephalometry; Dental Occlusion; Humans; Incisor; Mandible; Maxilla; Tooth Crown
PubMed: 28318162
DOI: 10.7518/hxkq.2016.06.011 -
Dento Maxillo Facial Radiology May 2011The present review article is aimed at describing the radiological methods utilized for human age identification. (Review)
Review
OBJECTIVE
The present review article is aimed at describing the radiological methods utilized for human age identification.
METHODS
The application and importance of radiological methods in human age assessment was discussed through the literature survey.
RESULTS
Following a literature search, 46 articles were included in the study and the relevant information is depicted in the article. Dental tissue is often preserved indefinitely after death. Implementation of radiography is based on the assessment of the extent of calcification of teeth and in turn the degree of formation of crown and root structures, along with the sequence and the stages of eruption. Several radiological techniques can be used to assist in both individual and general identification, including determination of gender, ethnic group and age. The radiographic method is a simpler and cheaper method of age identification compared with histological and biochemical methods. Radiographic and tomographic images have become an essential aid for human identification in forensic dentistry, particularly with the refinement of techniques and the incorporation of information technology resources.
CONCLUSION
Based on an appropriate knowledge of the available methods, forensic dentists can choose the most appropriate since the validity of age estimation crucially depends on the method used and its proper application. The multifactorial approach will lead to optimum age assessment. The legal requirements also have to be considered.
Topics: Adult; Age Determination by Teeth; Child; Forensic Dentistry; Humans; Molar, Third; Radiography, Dental; Tooth Calcification; Tooth Crown; Tooth Eruption; Tooth Root
PubMed: 21493876
DOI: 10.1259/dmfr/19478385 -
American Journal of Physical... Aug 2019This study explores the outer and inner crown of lower third and fourth premolars (P , P ) by analyzing the morphological variation among diverse modern human groups.
OBJECTIVES
This study explores the outer and inner crown of lower third and fourth premolars (P , P ) by analyzing the morphological variation among diverse modern human groups.
MATERIALS AND METHODS
We studied three-dimensional models of the outer enamel surface and the enamel-dentine junction (EDJ) from μCT datasets of 77 recent humans using both an assessment of seven nonmetric traits and a standard geometric morphometric (GM) analysis. For the latter, the dental crown was represented by four landmarks (dentine horns and fossae), 20 semilandmarks along the EDJ marginal ridge, and pseudolandmarks along the crown and cervical outlines.
RESULTS
Certain discrete traits showed significantly different regional frequencies and sexual dimorphism. The GM analyses of both P s and P s showed extensive overlap in shape variation of the various populations (classification accuracy 15-69%). The first principal components explained about 40% of shape variance with a correlation between 0.59 and 0.87 of the features of P s and P s. Shape covariation between P s and P s expressed concordance of high and narrow or low and broad crowns.
CONCLUSIONS
Due to marked intragroup and intergroup variation in GM analyses of lower premolars, discrete traits such as the number of lingual cusps and mesiolingual groove expression provide better geographic separation of modern human populations. The greater variability of the lingual region suggests a dominance of functional constraints over geographic provenience or sex. Additional information about functionally relevant aspects of the crown surface and odontogenetic data are needed to unravel the factors underlying dental morphology in modern humans.
Topics: Adolescent; Adult; Anthropology, Physical; Bicuspid; Child; Child, Preschool; Dental Enamel; Dentin; Female; Humans; Imaging, Three-Dimensional; Male; Middle Aged; Multivariate Analysis; Odontometry; Tooth Crown; X-Ray Microtomography; Young Adult
PubMed: 31099892
DOI: 10.1002/ajpa.23858 -
The Journal of Forensic... Dec 2021The purpose of this study was to assess the correlation between the known chronological age and the dental cementum thickness (DCT) in male and female subjects in...
UNLABELLED
The purpose of this study was to assess the correlation between the known chronological age and the dental cementum thickness (DCT) in male and female subjects in different age groups.
MATERIAL AND METHODS
The study sample consisted of 57 donor teeth of both sexes. Teeth were classified by donors' sex and divided into three age groups: 10-19, 30-39 and 60-69 years. Tooth roots were cut with transverse ground sections in the apical, middle, and cervical thirds. DCT measurements were made on photomicrographs of light microscope. The correlation between DCT and the chronological age was calculated using the Spearman correlation coefficient.
RESULTS
A positive correlation was found (r=0.47, p <0.001) between DCT and age of the donor. DCT decreased from apical to cervical ground section (median [IQR] apical section 216.72 [128.25-375.00] μm, middle section 158.44 [87.66-284.90] μm; cervical section 96.60 [70.05-165.59] µm). DCT variability was influenced by sex, number of tooth roots and the condition of the tooth crown. The influence differed depending on the location of the section, being most prominent cervically.
CONCLUSION
The present study showed correlation of DCT with age, with significant influence of sex, number of tooth roots, condition of the tooth crown and location of the root section.
Topics: Age Determination by Teeth; Child; Dental Cementum; Female; Humans; Male; Microscopy; Tooth; Tooth Crown; Tooth Root
PubMed: 34999579
DOI: No ID Found