1
|
Kenessey DE, Stojanowski CM, Paul KS. Evaluating predictions of the patterning cascade model of crown morphogenesis in the human lower mixed and permanent dentition. PLoS One 2024; 19:e0304455. [PMID: 38935640 DOI: 10.1371/journal.pone.0304455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 05/13/2024] [Indexed: 06/29/2024] Open
Abstract
OBJECTIVE The patterning cascade model of crown morphogenesis has been studied extensively in a variety of organisms to elucidate the evolutionary history surrounding postcanine tooth form. The current research is the first to use a large modern human sample to examine whether the crown configuration of lower deciduous and permanent molars aligns with expectations derived from the model. This study has two main goals: 1) to determine if metameric and antimeric pairs significantly differ in size, accessory trait expression, and relative intercusp spacing, and 2) assess whether the relative distance among early-forming cusps accounts for observed variation in accessory cusp expression. METHODS Tooth size, intercusp distance, and morphological trait expression data were collected from 3D scans of mandibular dental casts representing participants of the Harvard Solomon Islands Project. Paired tests were utilized to compare tooth size, accessory trait expression, and relative intercusp distance between diphyodont metameres and permanent antimeres. Proportional odds logistic regression was implemented to investigate how the odds of greater accessory cusp expression vary as a function of the distance between early-developing cusps. RESULTS/SIGNIFICANCE Comparing paired molars, significant differences were identified for tooth size and cusp 5 expression. Several relative intercusp distances emerged as important predictors of cusp 6 expression, however, results for cusp 5 and cusp 7 did not match expected patterns. These findings support previous quantitative genetic results and suggest the development of neighboring crown structures represents a zero-sum partitioning of cellular territory and resources. As such, this study contributes to a better understanding of the foundations of deciduous and permanent molar crown variation in humans.
Collapse
Affiliation(s)
- Dori E Kenessey
- Department of Anthropology, U niversity of Nevada, Reno, Nevada, United States of America
| | - Christopher M Stojanowski
- Center for Bioarchaeological Research, School of Human Evolution and Social Change, Arizona State University, Tempe, Arizona, United States of America
| | - Kathleen S Paul
- Department of Anthropology, University of Arkansas, Fayetteville, Arkansas, United States of America
| |
Collapse
|
2
|
Blankenship-Sefczek EC, Goodman AH, Hubbe M, Hunter JP, Guatelli-Steinberg D. Nutritional supplementation, tooth crown size, and trait expression in individuals from Tezonteopan, Mexico. PLoS One 2024; 19:e0305123. [PMID: 38843220 PMCID: PMC11156277 DOI: 10.1371/journal.pone.0305123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 05/23/2024] [Indexed: 06/09/2024] Open
Abstract
Understanding how epigenetic factors impact dental phenotypes can help refine the use of teeth for elucidating biological relationships among human populations. We explored relationships among crown size, principal cusp spacing, and accessory cusp expression in maxillary dental casts of nutritionally supplemented (n = 34) and non-supplemented (n = 39) individuals from Tezonteopan, Mexico. We hypothesized that the non-supplemented group would exhibit smaller molar crowns and reduced intercusp spacing. Since intercusp spacing is thought to be more sensitive to epigenetic influences than crown size, we predicted that the supplemented and non-supplemented groups would differ more in the former than the latter. Previous work suggests that molar accessory cusp expression may be elevated under conditions of stress. We therefore expected evidence of greater Carabelli and Cusp 5 trait expression in the non-supplemented group. We further hypothesized that anterior teeth would be affected by nutritional stress during development, with the non-supplemented group having smaller anterior tooth crowns and therefore limited space to form the tuberculum dentale. Finally, we tested whether the presence of molar accessory traits followed predictions of the Patterning Cascade Model of tooth morphogenesis in the entire sample. Our results supported the expectation that cusp spacing would differ more than molar crown size between the two groups. Carabelli trait showed little evidence of frequency differences between groups, but some evidence of greater trait scores in the non-supplemented group. The non-supplemented group also showed evidence of greater Cusp 5 frequency and expression. In the central incisors and canines, there was strong evidence for smaller crown sizes and reduced tuberculum dentale frequency in the non-supplemented group. With both groups pooled together, there was strong evidence of closer mesiodistal distances among principal cusps in molars with accessory cusps, a finding that is consistent with the PCM. Overall, our findings suggest that nutritional stress may affect accessory cusp expression.
Collapse
Affiliation(s)
- Erin C. Blankenship-Sefczek
- Department of Oral Biology, School of Dentistry, Creighton University, Omaha, Nebraska, United States of America
- Department of Anthropology, The Ohio State University, Columbus, Ohio, United States of America
| | - Alan H. Goodman
- School of Natural Sciences, Hampshire College, Amherst, Massachusetts, United States of America
| | - Mark Hubbe
- Department of Anthropology, The Ohio State University, Columbus, Ohio, United States of America
| | - John P. Hunter
- Department of Evolution, Ecology and Organismal Biology, The Ohio State University, Newark, Ohio, United States of America
| | | |
Collapse
|
3
|
Selig KR. Hypoconulid loss in cercopithecins: Functional and developmental considerations. J Hum Evol 2024; 187:103479. [PMID: 38181576 DOI: 10.1016/j.jhevol.2023.103479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 11/28/2023] [Accepted: 11/28/2023] [Indexed: 01/07/2024]
Abstract
Cercopithecins differ from papionins in lacking a M3 hypoconulid. Although this loss may be related to dietary differences, the functional and developmental ramifications of hypoconulid loss are currently unclear. The following makes use of dental topographic analysis to quantify shape variation in a sample of cercopithecin M3s, as well as in a sample of Macaca, which has a hypoconulid. To help understand the consequences of hypoconulid loss, Macaca M3s were virtually cropped to remove the hypoconulid and were also subjected to dental topographic analysis. The patterning cascade model and the inhibitory cascade model attempt to explain variation in cusp pattern and molar proportions, respectively. These models have both previously been used to explain patterns of variation in cercopithecines, but have not been examined in the context of hypoconulid loss. For example, previous work suggests that earlier developing cusps impact the development of later developing cusps (i.e., the hypoconulid) and that cercopithecines do not conform to the predictions of the inhibitory cascade model in that the size of the molars is not linear moving distally. Results of the current study suggest that the loss of the hypoconulid is associated with a reduction in dental topography among cercopithecins, which is potentially related to diet, although the connection to diet is not necessarily clear. Results also suggest that the loss of the hypoconulid can be explained by the patterning cascade model, and that hypoconulid loss explains the apparent lack of support for the inhibitory cascade model among cercopithecines. These findings highlight the importance of a holistic approach to studying variation in molar proportions and developmental models.
Collapse
Affiliation(s)
- Keegan R Selig
- Department of Evolutionary Anthropology, Duke University, Biological Sciences Building, 130 Science Drive, Durham, NC, 27708, USA.
| |
Collapse
|
4
|
Chapple SA, Skinner MM. A tooth crown morphology framework for interpreting the diversity of primate dentitions. Evol Anthropol 2023; 32:240-255. [PMID: 37486115 DOI: 10.1002/evan.21994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 03/25/2023] [Accepted: 06/19/2023] [Indexed: 07/25/2023]
Abstract
Variation in tooth crown morphology plays a crucial role in species diagnoses, phylogenetic inference, and the reconstruction of the evolutionary history of the primate clade. While a growing number of studies have identified developmental mechanisms linked to tooth size and cusp patterning in mammalian crown morphology, it is unclear (1) to what degree these are applicable across primates and (2) which additional developmental mechanisms should be recognized as playing important roles in odontogenesis. From detailed observations of lower molar enamel-dentine junction morphology from taxa representing the major primate clades, we outline multiple phylogenetic and developmental components responsible for crown patterning, and formulate a tooth crown morphology framework for the holistic interpretation of primate crown morphology. We suggest that adopting this framework is crucial for the characterization of tooth morphology in studies of dental development, discrete trait analysis, and systematics.
Collapse
Affiliation(s)
- Simon A Chapple
- School of Anthropology and Conservation, University of Kent, Canterbury, UK
| | - Matthew M Skinner
- School of Anthropology and Conservation, University of Kent, Canterbury, UK
- Department of Human Origins, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| |
Collapse
|
5
|
Wang JQ, Zhang Y, Pang M, Wang YQ, Yuan J, Peng H, Zhang W, Dai L, Li HW. Biomechanical Comparison of Six Different Root-Analog Implants and the Conventional Morse Taper Implant by Finite Element Analysis. Front Genet 2022; 13:915679. [PMID: 35769992 PMCID: PMC9234945 DOI: 10.3389/fgene.2022.915679] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 04/29/2022] [Indexed: 11/13/2022] Open
Abstract
Taper implants differ greatly from anatomical teeth in shape. In this study, seven three-dimensional finite element models were established, including a conventional taper implant and six root-analog implants with different root numbers and shapes. Vertical, horizontal, and oblique instantaneous loads of 100 N were applied to the models to obtain stress distribution in the implant, mucosa, cortical bone, and cancellous bone. ANSYS was used to perform the analysis under hypothetical experimental conditions. We find the stresses in all the implants and surrounding tissues varied by loading direction, the sequence of stress magnitude is vertical load, oblique load, and then horizontal load. The maximum stress values in root-analog implants were significantly less than in the taper implant. Moreover, stress distribution in the former was equalized contrary to the concentrated stress in the latter. Root-analog implants with different root geometry also revealed a pattern: stresses in multiple-root implant models were lower than those in single-root implants under the same load. The implant with a long and rounded root distributed the stress more uniformly, and it was mainly concentrated on the implant itself and cancellous bone. However, the opposite effect was observed in the short implant on mucosa and cortical bone. The root geometry of anatomical teeth can modify their functions. A uniform-shaped implant can hardly meet their functional requirements. Thus, the root-analog implant could be a possible solution.
Collapse
Affiliation(s)
- Jia-Qing Wang
- Department of Oral and Maxillofacial Surgery, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
- Jiangsu Province Key Laboratory of Oral Diseases, Nanjing, China
- Jiangsu Province Engineering Research Center of Stomatological Translational Medicine, Nanjing, China
| | - Yuan Zhang
- Department of Oral and Maxillofacial Surgery, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
- The Fourth Outpatient Department, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
| | - Min Pang
- Department of Oral and Maxillofacial Surgery, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
- The Fourth Outpatient Department, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
| | - Yue-Qiu Wang
- Department of Oral and Maxillofacial Surgery, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
- The Fourth Outpatient Department, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
| | - Jun Yuan
- Department of Oral and Maxillofacial Surgery, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
- The Fourth Outpatient Department, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
| | - Hui Peng
- Department of Oral and Maxillofacial Surgery, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
- The Fourth Outpatient Department, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
| | - Wen Zhang
- Department of Oral and Maxillofacial Surgery, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
- The Fourth Outpatient Department, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
| | - Lu Dai
- Department of Oral and Maxillofacial Surgery, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
- The Fourth Outpatient Department, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
- *Correspondence: Lu Dai, ; Hong-Wei Li,
| | - Hong-Wei Li
- Department of Oral and Maxillofacial Surgery, The Affiliated Stomatological Hospital of Nanjing Medical University, Nanjing, China
- Jiangsu Province Key Laboratory of Oral Diseases, Nanjing, China
- *Correspondence: Lu Dai, ; Hong-Wei Li,
| |
Collapse
|
6
|
Roksandic M, Radović P, Lindal J, Mihailović D. Early Neanderthals in contact: The Chibanian (Middle Pleistocene) hominin dentition from Velika Balanica Cave, Southern Serbia. J Hum Evol 2022; 166:103175. [PMID: 35339947 DOI: 10.1016/j.jhevol.2022.103175] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 02/16/2022] [Accepted: 02/16/2022] [Indexed: 12/26/2022]
Abstract
Neanderthals are Eurasian fossil hominins whose distinctive morphology developed in the southwestern corner of Europe and later spread throughout the continent, reaching Southwest Asia before the Late Pleistocene and spreading into Central Asia by 59-49 ka. The timing, tempo, and route of the Neanderthal movements eastward are poorly documented. The earliest probable evidence of Neanderthals in Asia comes from Karain E Cave (Anatolia, Turkey), dated to 250-200 ka. We present four Chibanian (Middle Pleistocene) hominin specimens, representing at least two individuals, from Velika Balanica Cave (Serbia): a permanent upper third molar (BH-2), a deciduous upper fourth premolar (BH-3) refitted to a poorly preserved maxillary fragment with the permanent first molar in the alveolus (BH-4), and a permanent upper central incisor (BH-5). We provide descriptions of the teeth, as well as a comparative analysis of the well-preserved M1 (BH-4), including assessments of cusp angles, relative occlusal polygon area, relative cusp base areas, two- and three-dimensional enamel thickness, and taurodontism. Morphology of both the occlusal surface and the enamel dentine junction of the M1 indicates that the maxillary fragment and associated dP4 belonged to an early Neanderthal child. The heavily worn I1 and M3 are consistent with the Neanderthal morphology, although they are less distinct taxonomically. These Chibanian remains with provenance from layer 3a are constrained by two thermoluminescence dates: 285 ± 34 ka and 295 ± 74 ka. They represent the earliest current evidence of Neanderthal spread into the Eastern Mediterranean Area. We discuss these findings in light of recent direct evidence for cultural connections between Southwestern Asia and Southeast Europe in the Chibanian.
Collapse
Affiliation(s)
- Mirjana Roksandic
- Department of Anthropology, University of Winnipeg, 515 Portage Avenue, Winnipeg, MB, R3B 2E9, Canada; Department of Anthropology, University of Manitoba, 432 Fletcher Argue Building, 15 Chancellor Circle, Winnipeg, MB, R3T 2N2, Canada; Fellow, DFG Center for Advanced Studies 'Words, Bones, Genes, Tools', University of Tübingen, 23 Rümelinstrasse, Room 603a, Tübingen, Germany.
| | - Predrag Radović
- Department of Archaeology, Faculty of Philosophy, University of Belgrade, 18-20 Čika Ljubina Belgrade, 11000, Serbia; National Museum Kraljevo, 2 Trg Svetog Save, Kraljevo, 36000, Serbia
| | - Joshua Lindal
- Department of Anthropology, University of Manitoba, 432 Fletcher Argue Building, 15 Chancellor Circle, Winnipeg, MB, R3T 2N2, Canada
| | - Dušan Mihailović
- Department of Archaeology, Faculty of Philosophy, University of Belgrade, 18-20 Čika Ljubina Belgrade, 11000, Serbia
| |
Collapse
|
7
|
Lifestyle changes and its effect towards the evolution of human dentition. EGYPTIAN JOURNAL OF FORENSIC SCIENCES 2022. [DOI: 10.1186/s41935-022-00268-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
The dentition of modern humans has evolved from their hominid ancestors to their current form. Factors regarding the changes of lifestyle such as dietary habits and usage of tools have affected the evolution of human dentition. This article aimed to discuss the effect of dietary changes on the evolution of human teeth. An online literature search in the PubMed database was conducted according to the inclusion criteria of this study.
Main body
The culture transition from a hunter-gatherer society to agriculture is followed by dietary changes, which result in a decrease of tooth wear due to more refined food sources in agricultural intensification. By analyzing the microwear pattern such as shear, striation, and pattern of the buccal teeth, the dietary hypothesis based on the occlusal tooth microwear analysis could be examined.
Conclusion
The dietary hypothesis based on the occlusal tooth microwear study could be tested by analyzing the microwear pattern (shear, striation, pattern) of the buccal teeth. Posterior teeth are more closely related to diet, while anterior teeth are related to non-dietary tooth-use behaviors, or using the teeth as a tool or third hand which causes more limited striations at the labial surface.
Collapse
|
8
|
Gong X, Zhang H, Xu X, Ding Y, Yang X, Cheng Z, Tao D, Hu C, Xiang Y, Sun Y. Tracing PRX1 + cells during molar formation and periodontal ligament reconstruction. Int J Oral Sci 2022; 14:5. [PMID: 35078971 PMCID: PMC8789835 DOI: 10.1038/s41368-021-00155-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2021] [Revised: 12/15/2021] [Accepted: 12/28/2021] [Indexed: 12/11/2022] Open
Abstract
Neural crest-derived mesenchymal stem cells (MSCs) are known to play an essential function during tooth and skeletal development. PRX1+ cells constitute an important MSC subtype that is implicated in osteogenesis. However, their potential function in tooth development and regeneration remains elusive. In the present study, we first assessed the cell fate of PRX1+ cells during molar development and periodontal ligament (PDL) formation in mice. Furthermore, single-cell RNA sequencing analysis was performed to study the distribution of PRX1+ cells in PDL cells. The behavior of PRX1+ cells during PDL reconstruction was investigated using an allogeneic transplanted tooth model. Although PRX1+ cells are spatial specific and can differentiate into almost all types of mesenchymal cells in first molars, their distribution in third molars is highly limited. The PDL formation is associated with a high number of PRX1+ cells; during transplanted teeth PDL reconstruction, PRX1+ cells from the recipient alveolar bone participate in angiogenesis as pericytes. Overall, PRX1+ cells are a key subtype of dental MSCs involved in the formation of mouse molar and PDL and participate in angiogenesis as pericytes during PDL reconstruction after tooth transplantation.
Collapse
Affiliation(s)
- Xuyan Gong
- Department of Implantology, School & Hospital of Stomatology, Tongji University, Shanghai, China.,Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai, China
| | - Han Zhang
- Department of Implantology, School & Hospital of Stomatology, Tongji University, Shanghai, China.,Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai, China
| | - Xiaoqiao Xu
- Department of Implantology, School & Hospital of Stomatology, Tongji University, Shanghai, China.,Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai, China
| | - Yunpeng Ding
- Department of Implantology, School & Hospital of Stomatology, Tongji University, Shanghai, China.,Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai, China
| | - Xingbo Yang
- Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Zhiyang Cheng
- Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Dike Tao
- Department of Implantology, School & Hospital of Stomatology, Tongji University, Shanghai, China.,Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai, China
| | - Congjiao Hu
- Department of Implantology, School & Hospital of Stomatology, Tongji University, Shanghai, China.,Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai, China
| | - Yaozu Xiang
- Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Yao Sun
- Department of Implantology, School & Hospital of Stomatology, Tongji University, Shanghai, China. .,Shanghai Engineering Research Center of Tooth Restoration and Regeneration, Shanghai, China.
| |
Collapse
|
9
|
Bastos VC, Gomez RS, Gomes CC. Revisiting the human dental follicle: From tooth development to its association with unerupted or impacted teeth and pathological changes. Dev Dyn 2021; 251:408-423. [PMID: 34324745 DOI: 10.1002/dvdy.406] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 07/16/2021] [Accepted: 07/22/2021] [Indexed: 02/06/2023] Open
Abstract
Dental follicles are involved in odontogenesis, periodontogenesis, and tooth eruption. Dental follicles are unique structures, considering that their remnants can persist within the jawbones after odontogenesis throughout life if the tooth does not erupt. Pathological changes may occur in these tissues as individuals age. The changes range from benign to life threatening. Thus, the assessment of age-related changes in dental follicles associated with unerupted teeth is of paramount importance. In this review, we summarize the physiological roles and changes in dental follicles in odontogenesis, tooth eruption, and aging, in addition to the pathological changes associated with these structures. We encourage investigators to consider this peculiar tissue as a unique model and explore its potential to clarify its importance from the viewpoints of developmental biology, tissue physiology, and pathology.
Collapse
Affiliation(s)
- Victor Coutinho Bastos
- Department of Oral Surgery and Pathology, Faculty of Dentistry, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil.,Department of Pathology, Biological Sciences Institute, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Ricardo Santiago Gomez
- Department of Oral Surgery and Pathology, Faculty of Dentistry, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil
| | - Carolina Cavaliéri Gomes
- Department of Pathology, Biological Sciences Institute, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, Brazil
| |
Collapse
|
10
|
Paul KS, Stojanowski CM, Hughes T, Brook A, Townsend GC. The genetic architecture of anterior tooth morphology in a longitudinal sample of Australian twins and families. Arch Oral Biol 2021; 129:105168. [PMID: 34174590 DOI: 10.1016/j.archoralbio.2021.105168] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 05/24/2021] [Accepted: 05/25/2021] [Indexed: 12/21/2022]
Abstract
OBJECTIVE This study presents a quantitative genetic analysis of human anterior dental morphology in a longitudinal sample of known genealogy. The primary aim of this work is to generate a suite of genetic correlations within and between deciduous and permanent characters to access patterns of integration across the diphyodont dental complex. DESIGN Data were recorded from casted tooth crowns representing participants of a long-term Australian twin and family study (deciduous n = 290, permanent n = 339). Morphological trait expression was observed and scored following Arizona State University Dental Anthropology System standards. Bivariate genetic correlations were estimated using maximum likelihood variance decomposition models in SOLAR v.8.1.1. RESULTS Genetic correlation estimates indicate high levels of integration between antimeres but low to moderate levels among traits within a tooth row. Only 9% of deciduous model comparisons were significant, while pleiotropy was indicated for one third of permanent trait pairs. Canine characters stood out as strongly integrated, especially in the deciduous dentition. For homologous characters across dentitions (e.g., deciduous i1 shoveling and permanent I1 shoveling), ∼70% of model comparisons yielded significant genetic correlations. CONCLUSIONS Patterns of genetic correlation suggest a morphological canine module that spans the primary and secondary dentition. Results also point to the existence of a genetic mechanism conserving morphology across the diphyodont dental complex, such that paired deciduous and permanent traits are more strongly integrated than characters within individual tooth rows/teeth.
Collapse
Affiliation(s)
- Kathleen S Paul
- Department of Anthropology, University of Arkansas, Fayetteville, AR 72701, United States.
| | - Christopher M Stojanowski
- Center for Bioarchaeological Research, School of Human Evolution and Social Change, Arizona State University, Tempe, AZ 85287, United States
| | - Toby Hughes
- Adelaide Dental School, The University of Adelaide, Adelaide, SA 5005, Australia
| | - Alan Brook
- Adelaide Dental School, The University of Adelaide, Adelaide, SA 5005, Australia; Barts and the London Dental Institute, Queen Mary University of London, London, E1, UK
| | - Grant C Townsend
- Adelaide Dental School, The University of Adelaide, Adelaide, SA 5005, Australia
| |
Collapse
|
11
|
Davies TW, Alemseged Z, Gidna A, Hublin JJ, Kimbel WH, Kullmer O, Spoor F, Zanolli C, Skinner MM. Accessory cusp expression at the enamel-dentine junction of hominin mandibular molars. PeerJ 2021; 9:e11415. [PMID: 34055484 PMCID: PMC8141287 DOI: 10.7717/peerj.11415] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 04/16/2021] [Indexed: 11/20/2022] Open
Abstract
Studies of hominin dental morphology frequently consider accessory cusps on the lower molars, in particular those on the distal margin of the tooth (C6 or distal accessory cusp) and the lingual margin of the tooth (C7 or lingual accessory cusp). They are often utilized in studies of hominin systematics, where their presence or absence is assessed at the outer enamel surface (OES). However, studies of the enamel-dentine junction (EDJ) suggest these traits may be more variable in development, morphology and position than previously thought. Building on these studies, we outline a scoring procedure for the EDJ expression of these accessory cusps that considers the relationship between these accessory cusps and the surrounding primary cusps. We apply this scoring system to a sample of Plio-Pleistocene hominin mandibular molars of Paranthropus robustus, Paranthropus boisei, Australopithecus afarensis, Australopithecus africanus, Homo sp., Homo habilis and Homo erectus from Africa and Asia (n = 132). We find that there are taxon-specific patterns in accessory cusp expression at the EDJ that are consistent with previous findings at the OES. For example, P. robustus M1s and M2s very often have a distal accessory cusp but no lingual accessory cusp, while H. habilis M1s and M2s show the opposite pattern. The EDJ also reveals a number of complicating factors; some apparent accessory cusps at the enamel surface are represented at the EDJ only by shouldering on the ridges associated with the main cusps, while other accessory cusps appear to have little or no EDJ expression at all. We also discuss the presence of double and triple accessory cusps, including the presence of a double lingual accessory cusp on the distal ridge of the metaconid in the type specimen of H. habilis (OH 7–M1) that is not clear at the OES due to occlusal wear. Overall, our observations, as well as our understanding of the developmental underpinnings of cusp patterning, suggest that we should be cautious in our comparisons of accessory cusps for taxonomic interpretations.
Collapse
Affiliation(s)
- Thomas W Davies
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Zeresenay Alemseged
- Department of Organismal Biology and Anatomy, University of Chicago, Chicago, Illinois, United States
| | - Agness Gidna
- Paleontology Unit, National Museum of Tanzania, Dar es Salaam, Tanzania
| | - Jean-Jacques Hublin
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.,Collège de France, Paris, France
| | - William H Kimbel
- Institute of Human Origins, and School of Human Evolution and Social Change, Arizona State University, Tempe, Arizona, United States
| | - Ottmar Kullmer
- Department of Paleobiology and Environment, Institute of Ecology, Evolution, and Diversity, Goethe University, Frankfurt, Germany.,Department of Palaeoanthropology, Senckenberg Research Institute and Natural History Museum Frankfurt, Frankfurt am Main, Germany
| | - Fred Spoor
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.,Centre for Human Evolution Research, Department of Earth Sciences, Natural History Museum, London, United Kingdom.,Department of Anthropology, University College London, London, United Kingdom
| | - Clément Zanolli
- Univ. Bordeaux, CNRS, MCC, PACEA, UMR 5199, F-33600 Pessac, France
| | - Matthew M Skinner
- Department of Human Evolution, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany.,School of Anthropology and Conservation, University of Kent, Canterbury, United Kingdom.,Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa
| |
Collapse
|
12
|
Fung S, Lee J, Yong R, Ranjitkar S, Kaidonis J, Pilbrow V, Panagiotopoulou O, Fiorenza L. A functional analysis of Carabelli trait in Australian aboriginal dentition. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2020; 174:375-383. [PMID: 32779189 DOI: 10.1002/ajpa.24120] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 06/16/2020] [Accepted: 07/08/2020] [Indexed: 12/24/2022]
Abstract
OBJECTIVES Carabelli is a nonmetric dental trait variably expressed as a small pit to a prominent cusp in the maxillary molars of modern humans. Investigations on the occurrence and expression rates of this trait have been conducted extensively, tracing its origin to genetic sources. However, there remains a lack of understanding about its potential role in chewing. In this study, we examine molar macrowear with the aim of reconstructing Carabelli trait occlusal dynamics occurring during chewing. METHODS We have examined 96 deciduous and permanent maxillary molars of children and young adults from Yuendumu, an Australian Aboriginal population that was at an early stage of transition from a nomadic and hunter-gatherer way of life to a more settled existence. We apply a well-established method, called Occlusal Fingerprint Analysis, which is a digital approach for analyzing dental macrowear allowing the reconstruction of jaw movements required to produce wear pattern specific to each tooth. RESULTS Carabelli trait slightly enlarges the surface functional area, especially in those molars where this feature is expressed in its cuspal form and it is closer to the occlusal plane. Moreover, the highly steep contact planes would also indicate that Carabelli wear areas contribute to increasing the shearing abilities of the occluded teeth, which are particularly important when processing fibrous and tough foods. CONCLUSIONS The macrowear analysis suggests that Carabelli trait in the Aboriginal people from Yuendumu slightly enhanced occlusion and probably played some functional role during mastication. Future biomechanical and microwear analyses could provide additional information on the mechanical adaptation of Carabelli trait in modern human dentition.
Collapse
Affiliation(s)
- Sarah Fung
- Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria, Australia
| | - Jinyoung Lee
- Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria, Australia
| | - Robin Yong
- Adelaide Dental School, University of Adelaide, Adelaide, South Australia, Australia
| | - Sarbin Ranjitkar
- Adelaide Dental School, University of Adelaide, Adelaide, South Australia, Australia
| | - John Kaidonis
- Adelaide Dental School, University of Adelaide, Adelaide, South Australia, Australia
| | - Varsha Pilbrow
- Australian Institute of Archaeology, La Trobe University, Melbourne, Victoria, Australia
| | - Olga Panagiotopoulou
- Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria, Australia
| | - Luca Fiorenza
- Monash Biomedicine Discovery Institute, Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria, Australia.,Earth Sciences, University of New England, Armidale, New South Wales, Australia
| |
Collapse
|
13
|
Fiorenza L, Menter CG, Fung S, Lee J, Kaidonis J, Moggi-Cecchi J, Townsend G, Kullmer O. The functional role of the Carabelli trait in early and late hominins. J Hum Evol 2020; 145:102816. [PMID: 32580080 DOI: 10.1016/j.jhevol.2020.102816] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 04/17/2020] [Accepted: 04/17/2020] [Indexed: 01/04/2023]
Abstract
The Carabelli trait is a dental feature that forms along the lingual margin of the protocone of deciduous and permanent maxillary molars. It is variably expressed, ranging from a small pit or furrow to a large cusp, and its development seems to be associated with crown size and molar cusp spatial configuration. The degree of expression of the Carabelli trait differs systematically between hominin taxa, and for this reason, it has been used extensively in the reconstruction of their phylogeny. However, the functional implications of having a large Carabelli trait remain unclear. In this study, we analyze the macrowear pattern of maxillary molars of early and late hominins using the occlusal fingerprint analysis method, an approach based on digital models of teeth that helps in reconstructing occlusal dynamics occurring during mastication. Tooth crowns with a small Carabelli cusp generally exhibit larger wear contact areas that extended cervically, while two additional new occlusal contact areas are common in teeth characterized by a large Carabelli cusp. These wear areas are created at the beginning of the chewing cycle, when occluding with the slopes of the lingual groove of the lower molars, between the metaconid and entoconid cusps. Advancing tooth wear leads to a slight enlargement of Carabelli occlusal contacts increasing their functional area. A steep inclination could be mechanically important in food reduction and in balancing the functional load distribution during mastication contacts. Steep wear areas are particularly developed in primates that process foods characterized by tough and fibrous textural properties. Future biomechanical and microwear texture analyses could provide additional information on the mechanical adaptation of this dental trait.
Collapse
Affiliation(s)
- Luca Fiorenza
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, 3800, Australia; Earth Sciences, University of New England, Armidale, NSW, 2351, Australia.
| | - Colin G Menter
- Department of Biology, University of Florence, 50122, Firenze, Italy
| | - Sarah Fung
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, 3800, Australia
| | - Jinyoung Lee
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, VIC, 3800, Australia
| | - John Kaidonis
- Adelaide Dental School, University of Adelaide, Adelaide, SA, 5005, Australia
| | | | - Grant Townsend
- Adelaide Dental School, University of Adelaide, Adelaide, SA, 5005, Australia
| | - Ottmar Kullmer
- Department of Paleoanthropology, Senckenberg Research Institute and Natural History Museum Frankfurt, Senckenberganlage 25, 60325 Frankfurt a. M., Germany; Department of Paleobiology and Environment, Institute of Ecology, Evolution, and Diversity, Johann Wolfgang Goethe University, Max-von-Laue-Str. 13, 60438, Frankfurt, Germany
| |
Collapse
|
14
|
Affiliation(s)
- David Jablonski
- Department of Geophysical Sciences University of Chicago Chicago Illinois
| |
Collapse
|
15
|
Stojanowski CM, Paul KS, Seidel AC, Duncan WN, Guatelli‐Steinberg D. Quantitative genetic analyses of postcanine morphological crown variation. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2019; 168:606-631. [DOI: 10.1002/ajpa.23778] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 11/20/2018] [Accepted: 12/26/2018] [Indexed: 01/05/2023]
Affiliation(s)
- Christopher M. Stojanowski
- Center for Bioarchaeological Research School of Human Evolution and Social Change, Arizona State University Tempe Arizona
| | - Kathleen S. Paul
- Center for Bioarchaeological Research School of Human Evolution and Social Change, Arizona State University Tempe Arizona
| | - Andrew C. Seidel
- Center for Bioarchaeological Research School of Human Evolution and Social Change, Arizona State University Tempe Arizona
| | - William N. Duncan
- Department of Sociology and Anthropology East Tennessee State University Johnson City Tennessee
| | | |
Collapse
|