Dataset Information

Variation of 3D outer and inner crown morphology in modern human mandibular premolars.

ABSTRACT:

Objectives

This study explores the outer and inner crown of lower third and fourth premolars (P₃ , P₄ ) 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 ?CT 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 P₃ s and P₄ 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 P₃ s and P₄ s. Shape covariation between P₃ s and P₄ 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.

SUBMITTER: Krenn VA

PROVIDER: S-EPMC6767701 | biostudies-literature | 2019 Aug

REPOSITORIES: biostudies-literature

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Publications

Variation of 3D outer and inner crown morphology in modern human mandibular premolars.

Krenn Viktoria A VA Fornai Cinzia C Wurm Lisa L Bookstein Fred L FL Haeusler Martin M Weber Gerhard W GW

American journal of physical anthropology 20190517 4

<h4>Objectives</h4>This study explores the outer and inner crown of lower third and fourth premolars (P<sub>3</sub> , P<sub>4</sub> ) by analyzing the morphological variation among diverse modern human groups.<h4>Materials and methods</h4>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, t ...[more]

PMID: 31099892

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Project description:Importance:In diabetic macular edema (DME), identification of baseline markers on spectral-domain optical coherence tomography (SD-OCT) and their association with severity of diabetic retinopathy (DR) might aid in disease management and the design of future trials. Objective:To examine associations between DR severity, retinal morphology on SD-OCT, and visual acuity in participants with DME. Design, Setting, and Participants:This cross-sectional observational case series was conducted at a single tertiary care referral center. Demographics, visual acuity, SD-OCT, and color fundus photographs of 80 individuals with DME (102 eyes) seen between December 28, 2013, and April 30, 2014, were analyzed between May 1 and July 31, 2016. Main Outcomes and Measures:Features captured on SD-OCT and thickness metrics. On SD-OCT we graded type and shape of DME, shape and presence of septae within the intraretinal cystoid abnormalities, presence of hyperreflective dots and foci, integrity of the external limiting membrane and ellipsoid zone, presence and extent of disorganization of the inner retinal layers (DRIL), and the status of the vitreomacular interface and epiretinal membrane. We measured retinal thickness at the fovea and at the site of maximum pathology, choroidal thickness at the fovea, and 1000 ?m temporal and nasal to the fovea. Color photographs were graded to derive a DR severity stage. Results:The mean (SD) age was 63 (11) years, and 30 participants (37.5%) were women. The odds of having DRIL were greater in eyes with disrupted external limiting membrane (odds ratio [OR], 4.4; 95% CI, 1.6-12.0; P?=?.003), disrupted ellipsoid zone (OR, 2.7; 95% CI, 1.0-7.2; P?=?.03), presence of epiretinal membrane (OR, 2.8; 95% CI, 1.0-7.4; P?=?.03), and increase in retinal thickness at the fovea (OR, 1.6; 95% CI, 1.1-2.2; P?<?.001). Occurrence of DRIL was more likely in eyes with proliferative DR (OR, 7.3; 95% CI, 1.7-31.4; P?=?.007). Mean visual acuity decreased by approximately 4.7 letters for each 100-?m increase in the average global DRIL (95% CI, -7.9 to 1.4; P?=?.006). Conclusions and Relevance:An association was found between DRIL and disruption of the outer retina and increasing DR severity. Further longitudinal studies seem warranted to determine whether DRIL is a clinically relevant noninvasive morphological marker in eyes with DME.

Dataset Information

Variation of 3D outer and inner crown morphology in modern human mandibular premolars.

Objectives

Materials and methods

Results

Conclusions

Publications

Variation of 3D outer and inner crown morphology in modern human mandibular premolars.

Similar Datasets

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