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Sgheiza V. Sex and ancestry patterning of residual correlations in human dental development: Cooperative genetic interaction and phenotypic plasticity. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2024; 184:e24908. [PMID: 38329212 DOI: 10.1002/ajpa.24908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 10/31/2022] [Accepted: 01/22/2024] [Indexed: 02/09/2024]
Abstract
OBJECTIVES Most research in human dental age estimation has focused on point estimates of age, and most research on dental development theories has focused on morphology or eruption. Correlations between developing teeth using ordinal staging have received less attention. The effect of demographic variables on these correlations is unknown. I tested the effect of reference sample demographic variables on the residual correlation matrix using the lens of cooperative genetic interaction (CGI). MATERIALS AND METHODS The sample consisted of Moorrees et al., Journal of Dental Research, 1963, 42, 1490-1502, scores of left mandibular permanent teeth from panoramic radiographs of 880 London children 3-22.99 years of age stratified by year of age, sex, and Bangladeshi or European ancestry. A multivariate cumulative probit model was fit to each sex/ancestry group (n = 220), each sex or ancestry (n = 440), and all individuals (n = 880). Residual correlation matrices from nine reference sample configurations were compared using Bartlett's tests of between-sample difference matrices against the identity matrix, hierarchical cluster analysis, and dendrogram cophenetic correlations. RESULTS Bartlett's test results were inconclusive. Cluster analysis showed clustering by tooth class, position within class, and developmental timing. Clustering patterns and dendrogram correlations showed similarity by sex but not ancestry. DISCUSSION Expectations of CGI were supported for developmental staging. This supports using CGI as a model for explaining patterns of variation within the dentition. Sex was found to produce consistent patterns of dental correlations, whereas ancestry did not. Clustering by timing of development supports phenotypic plasticity in the dentition and suggests shared environment over genetic ancestry to explain population differences.
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Affiliation(s)
- Valerie Sgheiza
- Department of Anthropology, University of Illinois at Urbana-Champaign, Urbana, USA
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Cavare A, Decaup PH, Boileau MJ, Garot E. Patterns and sexual dimorphism of non-syndromic hypodontia among a French orthodontic population. Arch Oral Biol 2024; 159:105894. [PMID: 38232498 DOI: 10.1016/j.archoralbio.2024.105894] [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: 11/21/2023] [Revised: 01/05/2024] [Accepted: 01/06/2024] [Indexed: 01/19/2024]
Abstract
OBJECTIVES This retrospective study aimed to estimate the prevalence of non-syndromic congenitally missing teeth (CMT) and to explore the frequency of CMT patterns in a French orthodontic population. In addition, the study sought to assess sex-based differences in CMT patterns. DESIGN Panoramic radiographs of 4569 orthodontic patients between 9 and 21 years-old performed over a 16-year period (2006-2022) were examined to identify non-syndromic tooth agenesis, excluding third molars. A chi-square test or a Fisher exact test were used to determine the difference in the prevalence of tooth agenesis between sex and between arches. RESULTS Tooth agenesis was observed in 7.3% of the sample (7.9% for females and 6.6% for males). Approximately 86% of the included subjects presented 1 or 2 missing teeth. Single tooth agenesis was significantly more frequent in females than males (p = 0.002, χ2). In total, 23 of the 67 different patterns of CMT observed, were present more than once. 75.5% of male patients and 79.5% of female patients presented one or both missing lateral incisors or second premolars, rarely affected at the same time. This study showed no sex difference in the patterns of tooth agenesis. LIMITATIONS This study has limitations due to its retrospective nature and our findings apply solely to an orthodontic population from a white ethnic background. CONCLUSIONS Clinicians should be aware of this particular incisor/premolar phenotype regardless of biological sex. Issues associated with congenitally missing teeth can be managed more effectively with early teenage diagnosis.
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Affiliation(s)
- Anaïs Cavare
- Univ. Bordeaux, CNRS, MCC, PACEA, UMR 5199, Pessac F-33600, France
| | - Pierre-Hadrien Decaup
- Univ. Bordeaux, CNRS, MCC, PACEA, UMR 5199, Pessac F-33600, France; Univ. de Bordeaux, UFR des Sciences Odontologiques, Bordeaux, France; Centre de Compétence des Maladies Rares Orales et Dentaires, CCMR O-Rares, C.H.U. de Bordeaux, Bordeaux, France
| | - Marie-José Boileau
- Univ. de Bordeaux, UFR des Sciences Odontologiques, Bordeaux, France; Centre de Compétence des Maladies Rares Orales et Dentaires, CCMR O-Rares, C.H.U. de Bordeaux, Bordeaux, France
| | - Elsa Garot
- Univ. Bordeaux, CNRS, MCC, PACEA, UMR 5199, Pessac F-33600, France; Univ. de Bordeaux, UFR des Sciences Odontologiques, Bordeaux, France; Centre de Compétence des Maladies Rares Orales et Dentaires, CCMR O-Rares, C.H.U. de Bordeaux, Bordeaux, France.
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Miyazaki J, Kondo S, Tanijiri T, Negishi S. Morphological differences between the first and second maxillary premolar crowns: A three-dimensional surface homologous modeling analysis. J Oral Biosci 2024; 66:20-25. [PMID: 38280717 DOI: 10.1016/j.job.2024.01.010] [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: 11/22/2023] [Revised: 01/21/2024] [Accepted: 01/22/2024] [Indexed: 01/29/2024]
Abstract
OBJECTIVES The current study used a three-dimensional (3D) surface homologous modeling to analyze the structure of maxillary first premolar (P1) and second premolar (P2) crowns, to identify any morphological differences between them, particularly in their cuspal structures. METHODS The study sample comprised 27 male elementary and junior high school students from Chiba Prefecture, Japan. Plaster casts were collected and the 3D coordinates were used to measure the crown structures. Thereafter, principal component (PC) analysis was carried out using the 3D coordinates of the homologous models, containing 4498 anatomical data points, including 9 landmarks. RESULTS The findings indicated that P1 was significantly larger than P2, despite both teeth exhibiting similar intercuspal distances. The homologous model analysis revealed that 61.5 % of the total variance could be explained up to the fourth PC. Overall size and shape in the mesiodistal and buccolingual directions were estimated using PC1 and PC2, respectively. Both components highlighted a shape factor, indicating that the buccal cusp was more well-developed than the lingual cusp in P1 compared to P2. CONCLUSIONS The variations in the size of the mesial and distal premolar teeth and the relationships between the cusps in the completed tooth crowns can be explained using molecular biology developmental models.
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Affiliation(s)
- Julie Miyazaki
- Department of Orthodontics, School of Dentistry at Matsudo, Nihon University, Chiba, Japan
| | - Shintaro Kondo
- Research Institute of Oral Science, School of Dentistry at Matsudo, Nihon University, Chiba, Japan.
| | | | - Shinichi Negishi
- Department of Orthodontics, School of Dentistry at Matsudo, Nihon University, Chiba, Japan
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Štamfelj I, Hitij T, Strmšek L. Radix entomolaris and radix paramolaris: A cone-beam computed tomography study of permanent mandibular molars in a large sample from Slovenia. Arch Oral Biol 2024; 157:105842. [PMID: 37979392 DOI: 10.1016/j.archoralbio.2023.105842] [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: 07/16/2023] [Revised: 10/29/2023] [Accepted: 11/01/2023] [Indexed: 11/20/2023]
Abstract
OBJECTIVES To investigate the prevalence, unilateral/bilateral concurrency, and external morphology of permanent mandibular molars (PMMs) with radix entomolaris (RE) and radix paramolaris (RP) in a sample from Slovenia. DESIGN Medium field-of-view cone-beam computed tomography images of 1315 participants (681 males, 634 females) aged 13-90 years (mean age 45.5) were retrospectively examined. A total of 1363 first, 1824 second, and 1314 third PMMs were evaluated. The external morphology of the affected teeth was categorized according to Carlsen and Alexandersen's classifications. RESULTS The individual-level RE frequencies in the first, second, and third PMMs were 1.6%, 1.9%, and 10.1%, respectively. The respective RP frequencies were 0%, 1.8%, and 3.2%. The first PMMs exclusively exhibited type A RE morphology, whereas in the second and third PMMs, types B and AC morphologies predominated. Bilateral concurrence rates were low (0-7.1%), with the exception of type A RE in first PMMs (62.5%). RE occurrences in the first and second PMMs were correlated (odds ratio = 70.2; 95% confidence interval 17.4 -282.7; P < 0.001). In concurrent cases, the second PMM followed its anterior neighbor in expressing type A morphology, and conversely, all affected second PMMs standing next to a two-rooted first PMM exhibited non-type A morphology. CONCLUSIONS In this sample, the first and second PMMs exhibited low supernumerary root frequencies comparable to those of other European samples. The third PMM was most often affected. The presence of RE on the first PMM increased the possibility of its presence on the adjacent second PMM and vice versa.
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Affiliation(s)
- Iztok Štamfelj
- Department of Dental Diseases and Dental Morphology, Faculty of Medicine, University of Ljubljana, Hrvatski trg 6, SI-1000 Ljubljana, Slovenia; Department of Operative Dentistry and Endodontics, University Medical Center Ljubljana, Hrvatski trg 6, SI-1000 Ljubljana, Slovenia.
| | - Tomaž Hitij
- Department of Dental Diseases and Dental Morphology, Faculty of Medicine, University of Ljubljana, Hrvatski trg 6, SI-1000 Ljubljana, Slovenia; Institute for Palaeobiology and Evolution, Novi trg 59, SI-1241 Kamnik, Slovenia
| | - Lucija Strmšek
- Department of Dental Diseases and Dental Morphology, Faculty of Medicine, University of Ljubljana, Hrvatski trg 6, SI-1000 Ljubljana, Slovenia
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Fang Z, Atukorallaya D. Count Me in, Count Me out: Regulation of the Tooth Number via Three Directional Developmental Patterns. Int J Mol Sci 2023; 24:15061. [PMID: 37894742 PMCID: PMC10606784 DOI: 10.3390/ijms242015061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 10/05/2023] [Accepted: 10/08/2023] [Indexed: 10/29/2023] Open
Abstract
Tooth number anomalies, including hyperdontia and hypodontia, are common congenital dental problems in the dental clinic. The precise number of teeth in a dentition is essential for proper speech, mastication, and aesthetics. Teeth are ectodermal organs that develop from the interaction of a thickened epithelium (dental placode) with the neural-crest-derived ectomesenchyme. There is extensive histological, molecular, and genetic evidence regarding how the tooth number is regulated in this serial process, but there is currently no universal classification for tooth number abnormalities. In this review, we propose a novel regulatory network for the tooth number based on the inherent dentition formation process. This network includes three intuitive directions: the development of a single tooth, the formation of a single dentition with elongation of the continual lamina, and tooth replacement with the development of the successional lamina. This article summarizes recent reports on early tooth development and provides an analytical framework to classify future relevant experiments.
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Affiliation(s)
| | - Devi Atukorallaya
- Department of Oral Biology, Dr. Gerald Niznick College of Dentistry, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB R3E0W2, Canada;
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Ranjitkar S, Wong C, Edwards S, Anderson PJ. Computed tomography assessment of hypodontia and crown size in hemifacial microsomia. Arch Oral Biol 2023; 147:105633. [PMID: 36738488 DOI: 10.1016/j.archoralbio.2023.105633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 01/22/2023] [Accepted: 01/26/2023] [Indexed: 01/29/2023]
Abstract
OBJECTIVE Our aims were to assess the prevalence of hypodontia in unilateral hemifacial microsomia (HFM), and to compare tooth (crown) size between affected and unaffected sides. DESIGN In a retrospective cross-sectional study of South Australians, computed tomography (CT) scans were used to assess hypodontia and crown size (mesiodistal length, buccolingual width and crown height). The inclusion criteria were the absence of other congenital anomalies and the availability of CT scans. The exclusion criteria were the lack of extraction history or reproducible landmarks for morphometric assessment. The final sample comprised 41 participants in both dentitions, including 32 children and 9 adults (median age 13.9 years, range 0.4 - 47.6 years; 19 males and 22 females). Hypodontia was assessed in all participants, and the permanent crown size in 30 (73.2%) participants. Linear mixed-effects models were performed to determine if crown size was significantly different between the two sides, controlling for sex, HFM severity, and tooth and jaw type. RESULTS Hypodontia occurred in none of the participants in the primary dentition, but in 6/30 (20%) participants in the permanent dentition (3/30 each on the affected and unaffected sides). There was no significant difference in the mean crown dimensions between the two sides, but the crown size was larger in males (p < 0.05), except for mesiodistal length, and became progressively smaller with increased HFM severity (p < 0.05). CONCLUSIONS Hypodontia spared the primary dentition but featured prominently in the permanent dentition. The permanent crown dimensions were unaltered between the two sides.
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Affiliation(s)
- Sarbin Ranjitkar
- Adelaide Dental School, The University of Adelaide, Adelaide, SA, Australia.
| | - Calvin Wong
- Adelaide Dental School, The University of Adelaide, Adelaide, SA, Australia
| | - Suzanne Edwards
- Adelaide Health Technology Assessment (AHTA), School of Public Health, University of Adelaide, Adelaide, Australia
| | - Peter J Anderson
- Adelaide Dental School, The University of Adelaide, Adelaide, SA, Australia; South Australian Health and Medical Research Institute, Adelaide, SA, Australia; Mesenchymal Stem Cell Laboratory, School of Biomedicine, The University of Adelaide, Adelaide, SA, Australia; Cleft and Craniofacial South Australia, Women's and Children's Hospital, Adelaide, SA, Australia
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Selvaraj M, Sennimalai K, Samrit VD, Duggal R. A Rare Incidence of Nonsyndromic Mandibular Incisor Agenesis in a Three-generation Family: Case Report and Literature Review. Int J Clin Pediatr Dent 2023; 16:388-395. [PMID: 37519973 PMCID: PMC10373786 DOI: 10.5005/jp-journals-10005-2539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/01/2023] Open
Abstract
Hypodontia is an inherited condition involving the absence of one to six teeth. The permanent dentition is the most frequently affected; however, it may also affect the primary dentition. A congenitally missing tooth (CMT) is the most common dental abnormality, with the missing mandibular second premolar, maxillary lateral incisor, maxillary second premolar, and mandibular central incisor accounting for 90% of CMT in hypodontia studies. The etiology of CMT has been attributed to environmental and genetic contributing factors, with the latter having a strong influence. It may occur in isolation or in association with syndromes. Congenitally missing mandibular incisor is more common in the Asian population and females. Depending on the number and location of missing teeth, hypodontia may be a considerable issue for the clinician since it may impact occlusal balance, mastication, speech, and esthetics and often requires a multidisciplinary approach. Missing mandibular incisors are of particular interest to orthodontists because of the possibility of mandibular retrognathism, the potential for the development of malocclusion, and difficulty in achieving a balanced occlusion. This case report describes the skeletal and dental features of a nonsyndromic familial occurrence of missing mandibular incisors in three generations. A comprehensive literature search was also performed to review the familial cases with missing mandibular incisors. How to cite this article Selvaraj M, Sennimalai K, Samrit VD, et al. A Rare Incidence of Nonsyndromic Mandibular Incisor Agenesis in a Three-generation Family: Case Report and Literature Review. Int J Clin Pediatr Dent 2023;16(2):388-395.
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Affiliation(s)
- Madhanraj Selvaraj
- Department of Dentistry, Jawaharlal Institute of Postgraduate Medical Education and Research, Puducherry, India
| | - Karthik Sennimalai
- Department of Orthodontics, All India Institute of Medical Sciences, Jammu, Jammu & Kashmir, India
| | - Vilas D Samrit
- Department of Orthodontics and Dentofacial Deformities, Centre for Dental Education and Research, All India Institute of Medical Sciences, Delhi, India
| | - Ritu Duggal
- Department of Orthodontics and Dentofacial Deformities, Centre for Dental Education and Research, All India Institute of Medical Sciences, Delhi, India
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Kanchanasevee C, Chantarangsu S, Pittayapat P, Porntaveetus T. Patterns of nonsyndromic tooth agenesis and sexual dimorphism. BMC Oral Health 2023; 23:37. [PMID: 36691053 PMCID: PMC9869554 DOI: 10.1186/s12903-023-02753-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 01/13/2023] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND Sex dimorphism has been implicated in oral health differences and the pathogenesis of oral diseases, such as tooth agenesis, periodontal disease, dental caries, and tooth loss. Tooth agenesis (TA) is one of the most common developmental anomalies in humans, and its prevalence and patterns are different across ethnic groups. The aim of this study was to investigate the phenotypes and sex-associated patterns of nonsyndromic tooth agenesis (TA) in Thai dental patients. METHODS One thousand ninety panoramic radiographs were examined. One hundred and one subjects (37 males, 64 females, 15-20 years-old) with nonsyndromic TA were evaluated. Differences in TA prevalence between groups were analyzed using the chi-square or Fisher exact test. RESULTS The TA prevalence, excluding third molars, was 9.3% and more frequently found in the mandible compared with the maxilla. The maxilla demonstrated a higher prevalence of first premolar agenesis than the mandible (P = 0.012), while the mandible had a higher prevalence of second premolar agenesis than the maxilla (P = 0.031). There were significantly more males missing one tooth than females, however, there were more females missing two or more teeth than males (P = 0.042). A missing maxillary left lateral incisor was significantly more frequent in males (P = 0.019), while a missing mandibular right lateral incisor was more frequent in females (P = 0.025). In females, the pattern of two mandibular lateral incisors agenesis was the most common and significantly present in females more than males (P = 0.015). In contrast, the pattern of one mandibular left lateral incisor agenesis was only observed in males and significantly found in males more than females (P = 0.047). CONCLUSIONS We demonstrate sex-associated differences in nonsyndromic tooth agenesis. The prevalence of single tooth agenesis was higher in males, while that of two or more teeth agenesis was higher in females. We found different patterns of lateral incisor agenesis between males and females.
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Affiliation(s)
- Charinya Kanchanasevee
- Center of Excellence in Genomics and Precision Dentistry, Department of Physiology, Faculty of Dentistry, Chulalongkorn University, Bangkok, 10330, Thailand
- Geriatric Dentistry and Special Patients Care Program, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
| | - Soranun Chantarangsu
- Department of Oral Pathology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
| | - Pisha Pittayapat
- Department of Radiology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
| | - Thantrira Porntaveetus
- Center of Excellence in Genomics and Precision Dentistry, Department of Physiology, Faculty of Dentistry, Chulalongkorn University, Bangkok, 10330, Thailand.
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Kerekes-Máthé B, Mártha K, Bănescu C, O’Donnell MB, Brook AH. Genetic and Morphological Variation in Hypodontia of Maxillary Lateral Incisors. Genes (Basel) 2023; 14:231. [PMID: 36672972 PMCID: PMC9858681 DOI: 10.3390/genes14010231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 01/13/2023] [Accepted: 01/14/2023] [Indexed: 01/18/2023] Open
Abstract
(1) Background: Hypodontia has a multifactorial aetiology, in which genetic factors are a major component. Associated with this congenital absence, the formed teeth may show differences in size and shape, which may vary with the specific genetic variants and with the location of the missing teeth. The aims of the present study were to investigate a specific variant of MSX1, derive morphometric tooth measurements in a sample of patients with isolated maxillary lateral incisor agenesis and matched controls, and model the findings. (2) Methods: Genotyping of the MSX1 rs8670 genetic variant and morphometric measurements with a 2D image analysis method were performed for 26 hypodontia patients and 26 matched controls. (3) Results: The risk of upper lateral incisor agenesis was 6.9 times higher when the T allele was present. The morphometric parameters showed significant differences between hypodontia patients and controls and between the unilateral and bilateral agenesis cases. The most affected crown dimension in the hypodontia patients was the bucco-lingual dimension. In crown shape there was significant variation the Carabelli trait in upper first molars. (4) Conclusions: The MSX1 rs8670 variant was associated with variations in morphological outcomes. The new findings for compensatory interactions between the maxillary incisors indicate that epigenetic and environmental factors interact with this genetic variant. A single-level directional complex interactive network model incorporates the variations seen in this study.
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Affiliation(s)
- Bernadette Kerekes-Máthé
- Department of Morphology of Teeth and Dental Arches, Faculty of Dentistry, George Emil Palade University of Medicine, Pharmacy, Science and Technology of Targu-Mures, 540142 Targu-Mures, Romania
| | - Krisztina Mártha
- Department of Orthodontics, Faculty of Dentistry, George Emil Palade University of Medicine, Pharmacy, Science and Technology of Targu-Mures, 540142 Targu-Mures, Romania
| | - Claudia Bănescu
- Genetics Laboratory, Center for Advanced Medical and Pharmaceutical Research, George Emil Palade University of Medicine, Pharmacy, Science and Technology of Targu-Mures, 540142 Targu-Mures, Romania
| | | | - Alan H. Brook
- School of Dentistry, University of Adelaide, Adelaide, SA 5005, Australia
- Dental Institute, Barts and the London Medical Faculty, Queen Mary University of London, London E1 4NS, UK
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Yang G, Chen Y, Li Q, Benítez D, Ramírez LM, Fuentes-Guajardo M, Hanihara T, Scott GR, Acuña Alonzo V, Gonzalez Jose R, Bortolini MC, Poletti G, Gallo C, Rothhammer F, Rojas W, Zanolli C, Adhikari K, Ruiz-Linares A, Delgado M. Dental size variation in admixed Latin Americans: Effects of age, sex and genomic ancestry. PLoS One 2023; 18:e0285264. [PMID: 37141293 PMCID: PMC10159210 DOI: 10.1371/journal.pone.0285264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 04/19/2023] [Indexed: 05/05/2023] Open
Abstract
Dental size variation in modern humans has been assessed from regional to worldwide scales, especially under microevolutionary and forensic contexts. Despite this, populations of mixed continental ancestry such as contemporary Latin Americans remain unexplored. In the present study we investigated a large Latin American sample from Colombia (N = 804) and obtained buccolingual and mesiodistal diameters and three indices for maxillary and mandibular teeth (except third molars). We evaluated the correlation between 28 dental measurements (and three indices) with age, sex and genomic ancestry (estimated using genome-wide SNP data). In addition, we explored correlation patterns between dental measurements and the biological affinities, based on these measurements, between two Latin American samples (Colombians and Mexicans) and three putative parental populations: Central and South Native Americans, western Europeans and western Africans through PCA and DFA. Our results indicate that Latin Americans have high dental size diversity, overlapping the variation exhibited by the parental populations. Several dental dimensions and indices have significant correlations with sex and age. Western Europeans presented closer biological affinities with Colombians, and the European genomic ancestry exhibited the highest correlations with tooth size. Correlations between tooth measurements reveal distinct dental modules, as well as a higher integration of postcanine dentition. The effects on dental size of age, sex and genomic ancestry is of relevance for forensic, biohistorical and microevolutionary studies in Latin Americans.
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Affiliation(s)
- Guangrui Yang
- Ministry of Education Key Laboratory of Contemporary Anthropology and Collaborative Innovation Center of Genetics and Development, School of Life Sciences and Human Phenome Institute, Fudan University, Shanghai, China
| | - Yingjie Chen
- Ministry of Education Key Laboratory of Contemporary Anthropology and Collaborative Innovation Center of Genetics and Development, School of Life Sciences and Human Phenome Institute, Fudan University, Shanghai, China
| | - Qing Li
- Ministry of Education Key Laboratory of Contemporary Anthropology and Collaborative Innovation Center of Genetics and Development, School of Life Sciences and Human Phenome Institute, Fudan University, Shanghai, China
| | - Daniel Benítez
- Department of Anthropology, University of Kentucky, Lexington, Kentucky, United States of America
| | | | - Macarena Fuentes-Guajardo
- Departamento de Tecnología Médica, Facultad de Ciencias de la Salud, Universidad de Tarapacá, Arica, Chile
| | - Tsunehiko Hanihara
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Japan
| | - G Richard Scott
- Department of Anthropology, University of Nevada Reno, Reno, Nevada, United States of America
| | - Victor Acuña Alonzo
- Molecular Genetics Laboratory, National School of Anthropology and History, Mexico City, Mexico
| | - Rolando Gonzalez Jose
- Instituto Patagónico de Ciencias Sociales y Humanas, Centro Nacional Patagónico, CONICET, Puerto Madryn, Argentina
| | - Maria Catira Bortolini
- Departamento de Genética, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brasil
| | - Giovanni Poletti
- Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Carla Gallo
- Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | | | - Winston Rojas
- GENMOL (Genética Molecular), Universidad de Antioquia, Medellín, Colombia
| | | | - Kaustubh Adhikari
- School of Mathematics and Statistics, Faculty of Science, Technology, Engineering and Mathematics, The Open University, Milton Keynes, United Kingdom
| | - Andres Ruiz-Linares
- Ministry of Education Key Laboratory of Contemporary Anthropology and Collaborative Innovation Center of Genetics and Development, School of Life Sciences and Human Phenome Institute, Fudan University, Shanghai, China
- Laboratory of Biocultural Anthropology, Law, Ethics, and Health (Centre National de la Recherche Scientifique and Etablissement Français du Sang, UMR-7268), Aix-Marseille University, Marseille, France
| | - Miguel Delgado
- Ministry of Education Key Laboratory of Contemporary Anthropology and Collaborative Innovation Center of Genetics and Development, School of Life Sciences and Human Phenome Institute, Fudan University, Shanghai, China
- División Antropología, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, La Plata, República Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas, CONICET, Buenos Aires, República Argentina
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Maaranen N, Zakrzewski S, Schutkowski H. Who Were the Hyksos? CURRENT ANTHROPOLOGY 2022. [DOI: 10.1086/723141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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12
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Pojar T, Langstieh BT, Hemphill BE. An initial investigation of dental morphology variation among three southern Naga ethnic groups of Northeast India. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2022; 179:184-210. [PMID: 36790681 DOI: 10.1002/ajpa.24605] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 04/29/2022] [Accepted: 07/28/2022] [Indexed: 11/07/2022]
Abstract
OBJECTIVES This study examines dental morphology trait prevalence among three southern Naga groups and compares them to 10 ethnic groups from other regions of South Asia to accomplish two objectives: assess the biological relationship of these Tibeto-Burman-speakers to speakers of non-Tibeto-Burman languages in other South Asian regions, and determine which traits distinguish northeast Indians from other South Asians. METHODS Dental morphology traits were scored with the Arizona State University Dental Anthropology System. Tooth-trait combinations were evaluated for significant inter-trait correlation and intra-trait correspondence within dental fields. Comparisons were based on simple trait prevalence and with Smith's MMD. Affinities based on the former were accomplished with correspondence analysis and principal components analysis. Affinities based on the latter were undertaken with neighbor-joining cluster analysis and multidimensional scaling. RESULTS After elimination due to inter-trait correlations and uniform prevalence, biodistances based on the remaining 17 tooth-trait combinations identify significant differences between northeast Indians and other South Asian ethnic groups due to high frequencies of shoveling on the maxillary incisors and Cusp 6 on the mandibular molars coupled with low frequencies of Carabelli's trait and Cusp 5 on UM1 and UM2, respectively. CONCLUSIONS Patterns of biodistances obtained from dental morphology are consilient with those obtained from DNA indicating statistically significant differences between northeast Indians from members of ethnic groups of other regions of South Asia. Researchers should explore the sex-specific patterns. Biodistances should not be limited to "key" teeth within dental fields, for in almost every case traits present on mesial and distal teeth yield non-redundant information.
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Affiliation(s)
- Tsiapisa Pojar
- Department of Anthropology, North-Eastern Hill University, Shillong, India
| | | | - Brian E Hemphill
- Department of Anthropology, University of Alaska, Fairbanks, Fairbanks, Alaska, USA
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13
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Paul KS, Stojanowski CM, Hughes T, Brook AH, Townsend GC. Genetic Correlation, Pleiotropy, and Molar Morphology in a Longitudinal Sample of Australian Twins and Families. Genes (Basel) 2022; 13:genes13060996. [PMID: 35741762 PMCID: PMC9222655 DOI: 10.3390/genes13060996] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 05/24/2022] [Accepted: 05/25/2022] [Indexed: 01/01/2023] Open
Abstract
This study aims to expand our understanding of the genetic architecture of crown morphology in the human diphyodont dentition. Here, we present bivariate genetic correlation estimates for deciduous and permanent molar traits and evaluate the patterns of pleiotropy within (e.g., m1–m2) and between (e.g., m2–M1) dentitions. Morphology was observed and scored from dental models representing participants of an Australian twin and family study (deciduous n = 290, permanent n = 339). Data collection followed Arizona State University Dental Anthropology System standards. Genetic correlation estimates were generated using maximum likelihood variance components analysis in SOLAR v.8.1.1. Approximately 23% of deciduous variance components models and 30% of permanent variance components models yielded significant genetic correlation estimates. By comparison, over half (56%) of deciduous–permanent homologues (e.g., m2 hypocone–M1 hypocone) were significantly genetically correlated. It is generally assumed that the deciduous and permanent molars represent members of a meristic molar field emerging from the primary dental lamina. However, stronger genetic integration among m2–M1/M2 homologues than among paired deciduous traits suggests the m2 represents the anterior-most member of a “true” molar field. The results indicate genetic factors act at distinct points throughout development to generate homologous molar form, starting with the m2, which is later replaced by a permanent premolariform crown.
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Affiliation(s)
- Kathleen S. Paul
- Department of Anthropology, University of Arkansas, Fayetteville, AR 72701, USA
- Correspondence: ; Tel.: +1-479-718-1352
| | - Christopher M. Stojanowski
- Center for Bioarchaeological Research, School of Human Evolution and Social Change, Arizona State University, Tempe, AZ 85287, USA;
| | - Toby Hughes
- Adelaide Dental School, The University of Adelaide, Adelaide, SA 5005, Australia; (T.H.); (A.H.B.)
| | - Alan H. Brook
- Adelaide Dental School, The University of Adelaide, Adelaide, SA 5005, Australia; (T.H.); (A.H.B.)
- Barts and the London Dental Institute, Queen Mary University of London, London EC1M 6AX, UK
| | - Grant C. Townsend
- Adelaide Dental School, The University of Adelaide, Adelaide, SA 5005, Australia; (T.H.); (A.H.B.)
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14
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Boughner JC, Marchiori DF, Packota GV. Unexpected variation of human molar size patterns. J Hum Evol 2021; 161:103072. [PMID: 34628299 DOI: 10.1016/j.jhevol.2021.103072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 08/15/2021] [Accepted: 08/16/2021] [Indexed: 11/17/2022]
Abstract
A tenet of mammalian, including primate dental evolution, is the Inhibitory Cascade Model, where first molar (M1) size predicts in a linear cline the size and onset time of the second (M2) and third (M3) molars: a larger M1 portends a progressively smaller and later-developing M2 and M3. In contemporary modern Homo sapiens, later-developing M3s are less likely to erupt properly. The Inhibitory Cascade Model is also used to predict molar sizes of extinct taxa, including fossil Homo. The extent to which Inhibitory Cascade Model predictions hold in contemporary H. sapiens molars is unclear, including whether this tenet informs about molar initiation, development, and eruption. We tested these questions here. In our radiographic sample of 323 oral quadrants and molar rows from contemporary humans based on mesiodistal crown lengths, we observed the distribution of molar proportions with a central tendency around parity (M1 = M2 = M3) that parsed into 13 distinct molar size ratio patterns. These patterns presented at different frequencies (e.g., M1 > M2 > M3 in about one-third of cases) that reflected whether the molar row was located in the maxilla or mandible and included both linear (e.g., M1 < M2 < M3) and nonlinear molar size ratio progressions (e.g., M1 > M2 < M3). Up to four patterns were found in the same subject's mouth. Lastly, M1 size alone does not predict M3 size, developmental timing, or eruption; rather, M2 size is integral to predicting M3 size. Our study indicates that human molar size is genetically 'softwired' and sensitive to factors local to the human upper jaw vs. lower jaw. The lack of a single stereotypical molar size ratio for contemporary H. sapiens suggests that predictions of fossil H. sapiens molar sizes using the Inhibitory Cascade Model must be made with caution.
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Affiliation(s)
- Julia C Boughner
- Department of Anatomy, Physiology & Pharmacology, College of Medicine, University of Saskatchewan, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada.
| | - Denver F Marchiori
- Department of Anatomy, Physiology & Pharmacology, College of Medicine, University of Saskatchewan, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada.
| | - Garnet V Packota
- College of Dentistry, University of Saskatchewan, 105 Wiggins Road, Health Sciences Building, Saskatoon, SK, S7N 5E5, Canada
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15
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Irish JD, Grabowski M. Relative tooth size, Bayesian inference, and Homo naledi. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2021; 176:262-282. [PMID: 34190335 DOI: 10.1002/ajpa.24353] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 05/04/2021] [Accepted: 06/08/2021] [Indexed: 01/29/2023]
Abstract
OBJECTIVES Size-corrected tooth crown measurements were used to estimate phenetic affinities among Homo naledi (~335-236 ka) and 11 other Plio-Pleistocene and recent species. To assess further their efficacy, and identify dental evolutionary trends, the data were then quantitatively coded for phylogenetic analyses. Results from both methods contribute additional characterization of H. naledi relative to other hominins. MATERIALS AND METHODS After division by their geometric mean, scaled mesiodistal and buccolingual dimensions were used in tooth size apportionment analysis to compare H. naledi with Australopithecus africanus, A. afarensis, Paranthropus robustus, P. boisei, H. habilis, H. ergaster, H. erectus, H. heidelbergensis, H. neanderthalensis, H. sapiens, and Pan troglodytes. These data produce equivalently scaled samples unaffected by interspecific size differences. The data were then gap-weighted for Bayesian inference. RESULTS Congruence in interspecific relationships is evident between methods, and with many inferred from earlier systematic studies. However, the present results place H. naledi as a sister taxon to H. habilis, based on a symplesiomorphic pattern of relative tooth size. In the preferred Bayesian phylogram, H. naledi is nested within a clade comprising all Homo species, but it shares some characteristics with australopiths and, particularly, early Homo. DISCUSSION Phylogenetic analyses of relative tooth size yield information about evolutionary dental trends not previously reported in H. naledi and the other hominins. Moreover, with an appropriate model these data recovered plausible evolutionary relationships. Together, the findings support recent study suggesting H. naledi originated long before the geological date of the Dinaledi Chamber, from which the specimens under study were recovered.
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Affiliation(s)
- Joel D Irish
- Research Centre in Evolutionary Anthropology and Palaeoecology, School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, UK.,The Centre for the Exploration of the Deep Human Journey, University of the Witwatersrand, Johannesburg, South Africa
| | - Mark Grabowski
- Research Centre in Evolutionary Anthropology and Palaeoecology, School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, UK.,Centre for Ecology and Evolutionary Synthesis, Department of Biosciences, University of Oslo, Oslo, Norway
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16
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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.
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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
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17
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McFarlane G, Guatelli-Steinberg D, Loch C, White S, Bayle P, Floyd B, Pitfield R, Mahoney P. An inconstant biorhythm: The changing pace of Retzius periodicity in human permanent teeth. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2020; 175:172-186. [PMID: 33368148 DOI: 10.1002/ajpa.24206] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 11/06/2020] [Accepted: 12/06/2020] [Indexed: 12/25/2022]
Abstract
OBJECTIVES Human tooth enamel retains evidence of growth in the form of Retzius lines. The number of daily growth increments between the regularly occurring lines defines their repeat interval, or periodicity. Retzius periodicity is often incorporated into enamel formation times, age-at-death reconstructions, or used to provide a basis from which to explore an underlying biorhythm. Biological anthropologists typically assume that RP remains constant within an individual and does not vary along the tooth-row. Here, we test that assumption. MATERIALS AND METHODS RP was calculated from n = 223 thin sections of human permanent teeth from individuals of British and southern African origin. Forty individuals provided multiple teeth (n = 102 teeth) and a further 121 individuals each provided a single tooth. RESULTS We report first evidence that RP of permanent teeth does not always remain constant within an individual. Of those individuals that provided multiple teeth, 42% (n = 17/40) demonstrated a decrease in RP along the tooth row, with most shifting by two or more days (n = 11). Across the entire sample, mean RP of anterior teeth was significantly higher than molars. Mean premolar RP tended to be intermediate between anterior teeth and molars. DISCUSSION Our data do not support the assumption that RP invariably remains constant within the permanent teeth of an individual. Transferring RP from molars to incisors within an individual can result in a miscalculation of formation time and age-at-death by up to 1 year. Implications for biological anthropologists and the source of the underlying long period biorhythm are discussed.
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Affiliation(s)
- Gina McFarlane
- Human Osteology Lab, School of Anthropology and Conservation, University of Kent, Canterbury, UK
| | - Debbie Guatelli-Steinberg
- Human Osteology Lab, School of Anthropology and Conservation, University of Kent, Canterbury, UK.,Department of Anthropology, The Ohio State University, Columbus, Ohio, USA
| | - Carolina Loch
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, New Zealand
| | - Sophie White
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, New Zealand
| | | | - Bruce Floyd
- School of Social Sciences, University of Auckland, New Zealand
| | - Rosie Pitfield
- Human Osteology Lab, School of Anthropology and Conservation, University of Kent, Canterbury, UK
| | - Patrick Mahoney
- Human Osteology Lab, School of Anthropology and Conservation, University of Kent, Canterbury, UK
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18
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Scheiwiller M, Oeschger ES, Gkantidis N. Third molar agenesis in modern humans with and without agenesis of other teeth. PeerJ 2020; 8:e10367. [PMID: 33240669 PMCID: PMC7678444 DOI: 10.7717/peerj.10367] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 10/24/2020] [Indexed: 12/25/2022] Open
Abstract
Background The number of teeth in the human dentition is of interest both from developmental and evolutionary aspects. The present case-control study focused on the formation of third molars in modern humans aiming to shed more light on the most variable tooth class in the dentition. Materials and Methods For this reason, we investigated third molar formation in a sample of 303 individuals with agenesis of teeth other than third molars (agenesis group) and compared it to a sex and age matched control group of 303 individuals without agenesis of teeth other than third molars. Results The prevalence of third molar agenesis in the agenesis group was 50.8%, which is significantly higher than the 20.5% in the control group (p < 0.001). The chance of a missing third molar in the agenesis group was increased by 38.3% (p < 0.001), after controlling for the agenesis in other teeth factor. When considering the amount of missing third molars per individual, a clear tendency towards more missing third molars was evident in the agenesis group compared to the control group. The frequency of bilaterally missing third molars in the agenesis group was 29% in the maxilla, as well as in the mandible, which is about three times higher than the frequency of unilaterally missing third molars (p < 0.001). In the control group, bilaterally missing third molars occurred in 8.6% in the maxilla and 8.9% in the mandible. Conclusion The present results indicate that genetic factors involved in tooth agenesis affect also the dentition as a whole. Furthermore, the third molars are more vulnerable to factors involved in agenesis of other teeth and they are more often affected as a whole. These findings seem to be associated with the evolutionary trend in humans towards reduced molar number.
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Affiliation(s)
- Maya Scheiwiller
- Department of Orthodontics and Dentofacial Orthopedics, University of Bern, Bern, Switzerland
| | - Elias S Oeschger
- Department of Orthodontics and Dentofacial Orthopedics, University of Bern, Bern, Switzerland
| | - Nikolaos Gkantidis
- Department of Orthodontics and Dentofacial Orthopedics, University of Bern, Bern, Switzerland
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19
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Khalaf K, Seraj Z, Hussein H, Mando M. Root Dimensions in Patients with Mild Hypodontia and a Control Group. Eur J Dent 2020; 13:574-580. [PMID: 31891974 PMCID: PMC6938418 DOI: 10.1055/s-0039-1700658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Objectives
The aim of this study was to compare root dimensions (length and mesiodistal widths) between subjects with mild hypodontia and an age- and sex-matched control group.
Materials and Methods
Root dimension measurements of all permanent teeth excluding third molars were made on standardly taken orthopantomograms of 50 individuals (25 hypodontia and 25 controls) attending the University of Sharjah Dental Hospital. The length and two mesiodistal widths were measured for each fully formed root. The length of the root was measured digitally by drawing a line from the midpoint and bisecting the mesiodistal cemento-enamel junction (CEJ) of the tooth and extended to its apex. The mesiodistal widths of each root were measured at the cervical region and at half way of and perpendicular to the length of the root.
Statistical Analysis
Two sample
t
-tests were used to compare root dimension measurements between the hypodontia and control groups.
Results
There were no significant differences between genders with regard to root length or widths measurements, and therefore genders were combined for further analysis. Patients with hypodontia have significantly shorter root lengths than controls for the upper central incisors, upper canines, first premolars, and lower first molars (
p
< 0.05). Similarly, root width at the midpoint of the root was found to be less in hypodontia group than that in controls for the upper central incisors, lower first premolars, upper first molars, and all second premolars (
p
< 0.05). Similar pattern of differences was found with regard to the root width at the cervical region (
p
< 0.05).
Conclusions
Patients with hypodontia have shorter and narrower roots of the whole permanent dentition except the upper lateral incisors, lower incisors, lower canines, and all second molars when compared with controls. In effect, this may affect the orthodontic treatment planning and implant placement.
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Affiliation(s)
- Khaled Khalaf
- Department of Preventive and Restorative Dentistry, University of Sharjah, Sharjah, United Arab Emirates
| | - Zahra Seraj
- Department of Preventive and Restorative Dentistry, University of Sharjah, Sharjah, United Arab Emirates
| | - Hesham Hussein
- Department of Preventive and Restorative Dentistry, University of Sharjah, Sharjah, United Arab Emirates
| | - Mahmoud Mando
- Department of Preventive and Restorative Dentistry, University of Sharjah, Sharjah, United Arab Emirates
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20
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Brăescu R, Săvinescu SD, Tatarciuc MS, Zetu IN, Giuşcă SE, Căruntu ID. Pointing on the early stages of maxillary bone and tooth development - histological findings. ROMANIAN JOURNAL OF MORPHOLOGY AND EMBRYOLOGY = REVUE ROUMAINE DE MORPHOLOGIE ET EMBRYOLOGIE 2020; 61:167-174. [PMID: 32747908 PMCID: PMC7728135 DOI: 10.47162/rjme.61.1.19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 07/21/2020] [Indexed: 11/17/2022]
Abstract
Although the morphological stages of tooth development, in parallel with maxillary bone construction, are known for decades, the intimate mechanisms of early development of the oral cavity structures and tooth's proper and associated tissues are still incompletely elucidated. Nowadays, the research in embryology was shifted from the morphological to the molecular and genetic approach. This new approach is accomplished by using in vivo and in vitro experimental studies performed on animal models and cell lines. The interest in the knowledge of these events at gene and molecular level is still current, aiming to sustain the progress in the endorsement of novel regenerative and restorative therapies. However, the morphological standpoint maintains its interest, because the extrapolation of the results of experimental studies in humans requires a strong confirmation. Within this context, our work aims to analyze the histological characteristics of the maxillary bone and integrated tooth germs during the early stages of embryonic development. The study group consisted in mandible fragments obtained by dissection of the cephalic extremities collected from fetuses aged from 10 to 24 weeks, after medical or spontaneous abortions. The tissue specimens were processed for the histological exam. The histoarchitectonic traits of the initial stages of mandibular bone tissue and tooth development were assessed. The results revealed the dynamics of the ossification stages, from stages of early-dispersed intramembranous ossification to the organization of the dental alveoli, incorporated step-by-step in the maxillary body, and the simultaneous presence of tooth germs with different sizes and shapes, in accordance with the development stage. Our study complements the existing data regarding the embryonic period, bringing an important contribution for the enlargement of existing morphological, visual information for maxillary bone and tooth development.
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Affiliation(s)
- Radu Brăescu
- Department of Morphofunctional Sciences I - Pathology, Grigore T. Popa University of Medicine and Pharmacy, Iaşi, Romania; ,
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21
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Schottenstein NH, Hubbe M, Hunter J. Modules and Mosaics in the Evolution of the Tetonius – Pseudotetonius Dentition. J MAMM EVOL 2019. [DOI: 10.1007/s10914-019-09488-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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22
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Three-dimensional geometric morphometric analysis of tooth shape in hypodontia: II size variation. Anat Sci Int 2019; 95:85-96. [PMID: 31401789 DOI: 10.1007/s12565-019-00497-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Accepted: 07/24/2019] [Indexed: 10/26/2022]
Abstract
The study aimed to evaluate differences in tooth size between patients with hypodontia and those with normal complement of permanent teeth using three-dimensional geometric morphometric analysis. The number of anatomical landmarks was recorded on the clinical crown of the permanent teeth on three-dimensional scanned study models of hypodontia and in control subjects. The study sample comprised 120 patients with hypodontia (mild, moderate, severe) and 40 controls matched for age and sex. Tooth size differences were tested statistically using multivariate statistics. Size variation was for the most part found to be significant, especially when the control subjects were compared with the hypodontia groups. The explained variance among group membership was generally larger in the anterior and premolar region than in the molar region Sexual dimorphism was found less in the anterior region than in the posterior region; therefore, the sexes were pooled more often for teeth in the anterior region. Quantitative measurement of tooth size in patients with hypodontia may enhance the multidisciplinary management of these patients.
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23
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Monson TA, Boisserie J, Brasil MF, Clay SM, Dvoretzky R, Ravindramurthy S, Schmitt CA, Souron A, Takenaka R, Ungar PS, Yoo S, Zhou M, Zuercher ME, Hlusko LJ. Evidence of strong stabilizing effects on the evolution of boreoeutherian (Mammalia) dental proportions. Ecol Evol 2019; 9:7597-7612. [PMID: 31346425 PMCID: PMC6635932 DOI: 10.1002/ece3.5309] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 04/25/2019] [Accepted: 04/28/2019] [Indexed: 11/28/2022] Open
Abstract
The dentition is an extremely important organ in mammals with variation in timing and sequence of eruption, crown morphology, and tooth size enabling a range of behavioral, dietary, and functional adaptations across the class. Within this suite of variable mammalian dental phenotypes, relative sizes of teeth reflect variation in the underlying genetic and developmental mechanisms. Two ratios of postcanine tooth lengths capture the relative size of premolars to molars (premolar-molar module, PMM), and among the three molars (molar module component, MMC), and are known to be heritable, independent of body size, and to vary significantly across primates. Here, we explore how these dental traits vary across mammals more broadly, focusing on terrestrial taxa in the clade of Boreoeutheria (Euarchontoglires and Laurasiatheria). We measured the postcanine teeth of N = 1,523 boreoeutherian mammals spanning six orders, 14 families, 36 genera, and 49 species to test hypotheses about associations between dental proportions and phylogenetic relatedness, diet, and life history in mammals. Boreoeutherian postcanine dental proportions sampled in this study carry conserved phylogenetic signal and are not associated with variation in diet. The incorporation of paleontological data provides further evidence that dental proportions may be slower to change than is dietary specialization. These results have implications for our understanding of dental variation and dietary adaptation in mammals.
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Affiliation(s)
- Tesla A. Monson
- Department of Integrative BiologyUniversity of CaliforniaBerkeleyCalifornia
- Human Evolution Research CenterUniversity of CaliforniaBerkeleyCalifornia
- Museum of Vertebrate ZoologyUniversity of CaliforniaBerkeleyCalifornia
- Anthropologisches Institut und MuseumUniversität ZürichZürichSwitzerland
| | | | - Marianne F. Brasil
- Department of Integrative BiologyUniversity of CaliforniaBerkeleyCalifornia
- Human Evolution Research CenterUniversity of CaliforniaBerkeleyCalifornia
| | - Selene M. Clay
- Department of Integrative BiologyUniversity of CaliforniaBerkeleyCalifornia
- Department of Human GeneticsUniversity of ChicagoChicagoIllinois
| | - Rena Dvoretzky
- Department of Integrative BiologyUniversity of CaliforniaBerkeleyCalifornia
| | | | | | | | - Risa Takenaka
- Department of Integrative BiologyUniversity of CaliforniaBerkeleyCalifornia
- Museum of Vertebrate ZoologyUniversity of CaliforniaBerkeleyCalifornia
| | - Peter S. Ungar
- Department of AnthropologyUniversity of ArkansasFayettevilleArkansas
| | - Sunwoo Yoo
- Department of Integrative BiologyUniversity of CaliforniaBerkeleyCalifornia
| | - Michael Zhou
- Department of Integrative BiologyUniversity of CaliforniaBerkeleyCalifornia
| | | | - Leslea J. Hlusko
- Department of Integrative BiologyUniversity of CaliforniaBerkeleyCalifornia
- Human Evolution Research CenterUniversity of CaliforniaBerkeleyCalifornia
- Museum of Vertebrate ZoologyUniversity of CaliforniaBerkeleyCalifornia
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Hardin AM. Genetic contributions to dental dimensions in brown-mantled tamarins (Saguinus fuscicollis) and rhesus macaques (Macaca mulatta). AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2019; 168:292-302. [PMID: 30508220 PMCID: PMC6328332 DOI: 10.1002/ajpa.23744] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2018] [Revised: 10/11/2018] [Accepted: 10/16/2018] [Indexed: 12/16/2022]
Abstract
OBJECTIVES The use of dental metrics in phylogenetic reconstructions of fossil primates assumes variation in tooth size is highly heritable. Quantitative genetic studies in humans and baboons have estimated high heritabilities for dental traits, providing a preliminary view of the variability of dental trait heritability in nonhuman primate species. To expand upon this view, the heritabilities and evolvabilities of linear dental dimensions are estimated in brown-mantled tamarins (Saguinus fuscicollis) and rhesus macaques (Macaca mulatta). MATERIALS AND METHODS Quantitative genetic analyses were performed on linear dental dimensions collected from 302 brown-mantled tamarins and 364 rhesus macaques. Heritabilities were estimated in SOLAR using pedigrees from each population, and evolvabilities were calculated manually. RESULTS Tamarin heritability estimates range from 0.19 to 0.99, and 25 of 26 tamarin estimates are significantly different from zero. Macaque heritability estimates range from 0.08 to 1.00, and 25 out of 28 estimates are significantly different from zero. DISCUSSION Dental dimensions are highly heritable in captive brown-mantled tamarins and free-ranging rhesus macaques. The range of heritability estimates in these populations is broadly similar to those of baboons and humans. Evolvability tends to increase with heritability, although evolvability is high relative to heritability in some dimensions. Estimating evolvability helps to contextualize differences in heritability, and the observed relationship between evolvability and heritability in dental dimensions requires further investigation.
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Affiliation(s)
- Anna M Hardin
- Department of Pathology and Anatomical Sciences, University of Missouri, Columbia, Missouri
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Tadros M, Brook AH, Ranjitkar S, Townsend GC. Compensatory interactions between developing maxillary anterior teeth in a sample of twins. Arch Oral Biol 2019; 97:198-207. [DOI: 10.1016/j.archoralbio.2018.10.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 09/09/2018] [Accepted: 10/08/2018] [Indexed: 11/15/2022]
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Mallineni SK, Jayaraman J, Wong HM, King NM. Dental development in children with supernumerary teeth in the anterior region of maxilla. Clin Oral Investig 2018; 23:2987-2994. [PMID: 30374829 DOI: 10.1007/s00784-018-2709-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 10/17/2018] [Indexed: 10/28/2022]
Abstract
OBJECTIVE Development of human dentition has been used as a predictor for evaluating the growth and maturity of an individual. It is fairly identical in a specific population, but the effect of development on subjects with dental anomalies had not been fully explored, particularly on subjects with supernumerary teeth (ST). This study hence aims to evaluate the dental development of children with and without ST. MATERIALS AND METHODS Sample size calculation was conducted and 320 radiographs of subjects with and without supernumerary teeth (ST) were obtained from the archives of a teaching hospital. The subjects in both groups were age and sex matched. All the subjects belong to southern Chinese ethnicity aged 2 to 14 years. The left-side dentition was scored, and dental age (DA) was estimated by obtaining scores from the southern Chinese dental reference dataset. Paired t test was used to calculate the difference between chronological age and dental age (CA-DA) for boys and girls with and without ST and further based on the number and position of ST. RESULTS The difference between chronological age and dental age (CA-DA) was 0.10 years for boys and 0.19 years for girls with ST whilst 0.01 and 0.05 years for boys and girls without ST (p > 0.05). The boys with bilateral ST showed significant delay in dental development of 0.23 years (p < 0.05). Position of the ST did not have any influence on dental age. CONCLUSIONS No significant difference was observed in the dental development of children with and without supernumerary teeth. CLINICAL RELEVANCE Understanding dental development of children with supernumerary teeth may be useful in appropriate treatment planning of such conditions.
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Affiliation(s)
- Sreekanth K Mallineni
- Department of Paedodontics and Preventive Dentistry, Narayana Dental College and Hospital, Nellore, India
| | - Jayakumar Jayaraman
- Children's Dentistry & Orthodontics, School of Dentistry, International Medical University, 57000, Kuala Lumpur, Malaysia.
| | - Hai Ming Wong
- Paediatric Dentistry & Orthodontics, Faculty of Dentistry, The University of Hong Kong, 34, Hospital Road, Hong Kong, Hong Kong
| | - Nigel M King
- Paediatric Dentistry, School of Dentistry, University of Western Australia, Perth, WA, 6009, Australia
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Yong R, Ranjitkar S, Lekkas D, Halazonetis D, Evans A, Brook A, Townsend G. Three‐dimensional (3D) geometric morphometric analysis of human premolars to assess sexual dimorphism and biological ancestry in Australian populations. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2018; 166:373-385. [DOI: 10.1002/ajpa.23438] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Revised: 01/28/2018] [Accepted: 01/29/2018] [Indexed: 11/12/2022]
Affiliation(s)
- Robin Yong
- Adelaide Dental SchoolUniversity of AdelaideAdelaide South Australia 5005 Australia
| | - Sarbin Ranjitkar
- Adelaide Dental SchoolUniversity of AdelaideAdelaide South Australia 5005 Australia
| | - Dimitra Lekkas
- Adelaide Dental SchoolUniversity of AdelaideAdelaide South Australia 5005 Australia
| | - Demetrios Halazonetis
- School of DentistryNational and Kapodistrian University of AthensAthens 11527 Greece
| | - Alistair Evans
- School of Biological SciencesMonash UniversityClayton Victoria 3800 Australia
| | - Alan Brook
- Adelaide Dental SchoolUniversity of AdelaideAdelaide South Australia 5005 Australia
- Institute of DentistryQueen Mary University of LondonLondon E1 4NS United Kingdom
| | - Grant Townsend
- Adelaide Dental SchoolUniversity of AdelaideAdelaide South Australia 5005 Australia
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McLean BS, Helgen KM, Goodwin HT, Cook JA. Trait‐specific processes of convergence and conservatism shape ecomorphological evolution in ground‐dwelling squirrels. Evolution 2018; 72:473-489. [DOI: 10.1111/evo.13422] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 12/18/2017] [Indexed: 12/27/2022]
Affiliation(s)
- Bryan S. McLean
- Department of Biology and Museum of Southwestern Biology University of New Mexico Albuquerque New Mexico 87131
- Florida Museum of Natural History University of Florida Gainesville Florida 32611
| | - Kristofer M. Helgen
- School of Biological Sciences University of Adelaide Adelaide SA 5005 Australia
| | - H. Thomas Goodwin
- Department of Biology Andrews University Berrien Springs Michigan 49104
| | - Joseph A. Cook
- Department of Biology and Museum of Southwestern Biology University of New Mexico Albuquerque New Mexico 87131
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Kemoli AM, Junior TM. Bilateral Second Premolars Agenesia Together with a Unilateral Canine Radiculomegaly. Contemp Clin Dent 2017; 8:151-154. [PMID: 28566869 PMCID: PMC5426150 DOI: 10.4103/ccd.ccd_1136_16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Congenitally missing teeth is a common feature for the third molars. However, missing teeth, macrodontia and radiculomegaly occurring in a single patient is very rare. This article describes a case of agenesis of mandibular second premolars, radiculomegaly with dilacerations of a canine tooth together with elongated roots of other canines. All these features had been discerned through diagnostic radiographs taken during a routine treatment planning.
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Affiliation(s)
- Arthur Musakulu Kemoli
- Department of Paediatric Dentistry and Orthodontics, University of Nairobi, Nairobi, Kenya
| | - Thomas Munyao Junior
- Department of Paediatric Dentistry and Orthodontics, University of Nairobi, Nairobi, Kenya
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Gkantidis N, Katib H, Oeschger E, Karamolegkou M, Topouzelis N, Kanavakis G. Patterns of non-syndromic permanent tooth agenesis in a large orthodontic population. Arch Oral Biol 2017; 79:42-47. [PMID: 28288390 DOI: 10.1016/j.archoralbio.2017.02.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 02/23/2017] [Accepted: 02/27/2017] [Indexed: 12/26/2022]
Abstract
OBJECTIVE The aim of this study is to explore patterns of non-syndromic permanent tooth agenesis in a large orthodontic patient group. DESIGN A record review was performed in various orthodontic clinics to identify white patients with non-syndromic permanent tooth agenesis, excluding 3rd molars. Four hundred and fourteen subjects fulfilled the inclusion criteria. RESULTS In the 414 subjects with tooth agenesis, approximately 70% presented 1-2 missing teeth. Symmetric agenesis patterns were often observed in the sample (by jaw, by side, or crossed quadrants), with prevalence approaching 30% for cases with contralateral tooth agenesis within a jaw. In cases with 1 or 2 missing teeth, from the total number of potential tooth agenesis patterns in the sample, a certain part was evident, limiting the variation to 27.8% (44/158). In the entire sample, both in the maxilla and the mandible a certain incisor/premolar agenesis phenotype was observed in 59.0% of cases in isolated form. CONCLUSIONS Although there was variation in the tooth agenesis patterns, our findings suggest the involvement of particular genetic, epigenetic, and/or environmental factors in the formation of the entire dentition, which often lead to specific tooth agenesis phenotypes in cases where this process is disrupted. The present study provides a comprehensive categorization of orthodontic cases with tooth agenesis and can assist in planning future epidemiological and genetic studies.
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Affiliation(s)
- Nikolaos Gkantidis
- Department of Orthodontics and Dentofacial Orthopedics, University of Bern, Freiburgstrasse 7, CH-3010, Bern, Switzerland.
| | - Hattan Katib
- Department of Orthodontics and Dentofacial Orthopedics, University of Bern, Freiburgstrasse 7, CH-3010, Bern, Switzerland
| | - Elias Oeschger
- Department of Orthodontics and Dentofacial Orthopedics, University of Bern, Freiburgstrasse 7, CH-3010, Bern, Switzerland
| | - Marina Karamolegkou
- Department of Orthodontics, School of Dentistry, University of Athens, 2 Thivon Str, 115 27, Goudi, Athens, Greece
| | - Nikolaos Topouzelis
- Department of Orthodontics, Aristotle University of Thessaloniki, University Campus, 54 124, Thessaloniki, Greece
| | - Georgios Kanavakis
- Department of Orthodontics, Tufts University School of Dental Medicine, 1 Kneeland Street, MA 02111, Boston, USA
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Paul KS, Astorino CM, Bailey SE. The Patterning Cascade Model and Carabelli's trait expression in metameres of the mixed human dentition: exploring a morphogenetic model. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2016; 162:3-18. [DOI: 10.1002/ajpa.23080] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 08/08/2016] [Accepted: 08/13/2016] [Indexed: 01/09/2023]
Affiliation(s)
- Kathleen S. Paul
- Center for Bioarchaeological Research, School of Human Evolution and Social ChangeArizona State UniversityTempe Arizona85287
| | - Claudia M. Astorino
- The Graduate School and University Center, The City University of New YorkNew York New York10016
- New York Consortium in Evolutionary PrimatologyNew York New York10028
| | - Shara E. Bailey
- New York Consortium in Evolutionary PrimatologyNew York New York10028
- Center for the Study of Human Origins, Department of AnthropologyNew York UniversityNew York New York10012
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Nova Delgado M, Galbany J, Pérez-Pérez A. Molar shape variability in platyrrhine primates. J Hum Evol 2016; 99:79-92. [PMID: 27650581 DOI: 10.1016/j.jhevol.2016.07.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Revised: 07/18/2016] [Accepted: 07/22/2016] [Indexed: 11/26/2022]
Abstract
Recent phylogenetic analyses suggest that platyrrhines constitute a monophyletic group represented by three families: Cebidae, Atelidae, and Pitheciidae. Morphological variability between and within these three families, however, is widely discussed and debated. The aim of this study was to assess molar shape variability in platyrrhines, to explore patterns of interspecific variation among extant species, and to evaluate how molar shape can be used as a taxonomic indicator. The analyses were conducted using standard multivariate analyses of geometric morphometric data from 802 platyrrhine lower molars. The results indicated that the interspecific variation exhibited a highly homoplastic pattern related to functional adaptation of some taxa. However, phylogeny was also an important factor in shaping molar morphological traits, given that some phenotypic similarities were consistent with current phylogenetic positions. Our results show that the phylogenetic and functional signals of lower molar shape vary depending on the taxa and the tooth considered. Based on molar shape, Aotus showed closer similarities to Callicebus, as well as to some Cebidae and Ateles-Lagothrix, due to convergent evolutionary trends caused by similar dietary habits, or due to fast-evolving branches in the Aotus lineage, somewhat similar to the shape of Callicebus and Cebidae.
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Affiliation(s)
- Mónica Nova Delgado
- Secció de Zoologia i Antropologia Biològica, Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Universitat de Barcelona, Av. Diagonal 643, 08028 Barcelona, Spain
| | - Jordi Galbany
- Secció de Zoologia i Antropologia Biològica, Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Universitat de Barcelona, Av. Diagonal 643, 08028 Barcelona, Spain; Center for the Advanced Study of Human Paleobiology, Department of Anthropology, George Washington University, 800 22nd Street NW, Ste 6000, Washington, D.C. 20052, USA
| | - Alejandro Pérez-Pérez
- Secció de Zoologia i Antropologia Biològica, Departament de Biologia Evolutiva, Ecologia i Ciències Ambientals, Universitat de Barcelona, Av. Diagonal 643, 08028 Barcelona, Spain.
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Irish JD, Hemphill BE, de Ruiter DJ, Berger LR. The apportionment of tooth size and its implications in
Australopithecus sediba
versus other Plio‐pleistocene and recent African hominins. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2016; 161:398-413. [DOI: 10.1002/ajpa.23039] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2015] [Revised: 06/08/2016] [Accepted: 06/09/2016] [Indexed: 11/06/2022]
Affiliation(s)
- Joel D. Irish
- Research Centre in Evolutionary Anthropology and Palaeoecology, School of Natural Sciences and PsychologyLiverpool John Moores UniversityLiverpoolL3 3AF UK
- Evolutionary Studies Institute and Centre for Excellence in PaleoSciencesUniversity of the WitwatersrandPrivate Bag 3, WITS 2050Johannesburg South Africa
| | | | - Darryl J. de Ruiter
- Department of AnthropologyTexas A&M UniversityCollege Station TX77843
- Evolutionary Studies Institute and Centre for Excellence in PaleoSciencesUniversity of the WitwatersrandPrivate Bag 3, WITS 2050Johannesburg South Africa
| | - Lee R. Berger
- Evolutionary Studies Institute and Centre for Excellence in PaleoSciencesUniversity of the WitwatersrandPrivate Bag 3, WITS 2050Johannesburg South Africa
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Heikkinen T, Harila V, Ollikkala A, Alvesalo L. Primary tooth size asymmetry in twins and singletons. Orthod Craniofac Res 2016; 19:145-53. [PMID: 26898820 DOI: 10.1111/ocr.12122] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/23/2016] [Indexed: 12/01/2022]
Abstract
OBJECTIVES To explore asymmetry values of antimeric deciduous tooth crown dimensions in three types of twins: monozygotic (MZ), dizygotic same-sex (DZ) and opposite-sex (OS) vs. single-born controls. SETTING AND SAMPLE POPULATION Mesiodistal and labio-lingual crown dimensions of second deciduous molars and mesiodistal canine and first molar crown dimensions of 2159 children at 6-12 years of age were evaluated, originating from the US cross-sectional Collaborative Perinatal Study from the 1970s, including altogether MZ (n = 28), DZ same-sex (n = 33) and OS (n = 39) pairs. Single born (n = 1959) were used as controls. MATERIAL AND METHODS Dental casts were measured for comparison of variance relationships calculated from antimeric teeth, exhibiting fluctuating (FA), and directional (DA) asymmetry using anova. RESULTS Significant differences appeared in MZ and OS girls in DA of deciduous canines, which gain size in the first and second trimester, and deciduous second molars, which finally stop crown growth during the early post-natal period. Significantly, increased FA values appeared for lower deciduous canines and second molars, indicating greatest environmental stress in OS girls, MZ girls and DZ boys. Twin girls had more fluctuating and directional crown asymmetry than twin boys, but in some dimensions, the twins were more symmetric than controls. CONCLUSIONS Transmembrane hormonal influence between opposite-sex twins, and late gestational stress factors, caused by placental malfunction and/or monochorionicity, may be involved in asymmetric growth of antimers, during critical periods of crown size gain.
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Affiliation(s)
- T Heikkinen
- Oral Development and Orthodontics, Unit of Oral Health Sciences, University of Oulu, Oulu, Finland.,Medical Research Center, Oulu, Oulu, Finland.,Oulu University Hospital, Oulu, Finland
| | - V Harila
- Oral Development and Orthodontics, Unit of Oral Health Sciences, University of Oulu, Oulu, Finland.,Medical Research Center, Oulu, Oulu, Finland.,Oulu University Hospital, Oulu, Finland
| | - A Ollikkala
- Oral Development and Orthodontics, Unit of Oral Health Sciences, University of Oulu, Oulu, Finland.,Medical Research Center, Oulu, Oulu, Finland.,Oulu University Hospital, Oulu, Finland
| | - L Alvesalo
- Oral Development and Orthodontics, Unit of Oral Health Sciences, University of Oulu, Oulu, Finland.,Medical Research Center, Oulu, Oulu, Finland.,Oulu University Hospital, Oulu, Finland
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Elucidating the evolution of hominid dentition in the age of phenomics, modularity, and quantitative genetics. Ann Anat 2016; 203:3-11. [DOI: 10.1016/j.aanat.2015.05.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Revised: 05/17/2015] [Accepted: 05/18/2015] [Indexed: 12/11/2022]
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Kerekes-Máthé B, Brook AH, Mártha K, Székely M, Smith RN. Mild hypodontia is associated with smaller tooth dimensions and cusp numbers than in controls. Arch Oral Biol 2015. [DOI: 10.1016/j.archoralbio.2015.06.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Deepak V, Goryawala SN, Reddy Y, Chhabra RJ, Nandaprasad, Shah NK. Assessment of Ethnicity in Indian Population using Tooth Crown Metric Dental Traits. J Int Oral Health 2015; 7:83-7. [PMID: 26435624 PMCID: PMC4589727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
BACKGROUND Tooth crown dimensions vary between different ethnic groups, providing insights into the factors controlling human dental development. This present study compares permanent mesiodistal (MD) and buccolingual crown dimensions between four ethnic groups, highlighting patterns of tooth size between these groups and considers the findings in relation to genetic and environmental influences. MATERIALS AND METHODS MD and buccolingual tooth crown dimensions were recorded using digital vernier calipers on dental casts derived from four different human population: Iranians, Hindus, Muslims, and Christians. RESULTS Obtained measurements were subjected to statistical analysis. The Christian sample was found to have the largest teeth overall, whereas the Iranian sample generally displayed the smallest MD and buccolingual crown dimensions (P < 0.001). Comparisons of coefficients of variation for teeth within each class showed that the later-forming teeth displayed greater variation in MD size than the earlier-forming teeth. CONCLUSION The different patterns of tooth size observed between the study samples are thought to reflect differences in the relative contributions of genetic and environmental influences to dental development between the four population. Using a standardized methodology, significant differences in MD and buccolingual crown dimensions have been demonstrated between four human ethnic groups. There were also distinct differences in the patterns of crown size between the groups, with the later-forming teeth in each type generally showing greater size variation.
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Affiliation(s)
- V Deepak
- Senior Lecturer, Department of Oral Pathology, MR Ambedkar Dental College and Hospital, Bengaluru, Karnataka, India,Correspondence: Dr. Deepak V. 1/36, Cline Road, Cooke Town, Bengaluru - 560 005, Karnataka, India. Phone: +91-7411184210.
| | - S N Goryawala
- Associate Professor, Department of Dentistry, GMERS Medical College, Gotri, Vadodara, Gujarat, India
| | - Yashwanth Reddy
- Senior Lecturer, Department of Oral Pathology, Sri Rajiv Gandhi College of Dental Sciences and Hospital, Cholanagar, Bengaluru, Karnataka, India
| | - R J Chhabra
- Professor and Head, Department of Biochemistry, MP Shah Government Medical College and Guru Gobind Singh Hospital, Jamnagar, Gujrat, India
| | - Nandaprasad
- Reader, Department of Oral Pathology, Sri Rajiv Gandhi College of Dental Sciences and Hospital, Cholanagar, Bengaluru, Karnataka, India
| | - Nishit Kumar Shah
- Senior Lecturer, Department of Oral Surgery, Government Dental College, Jamnagar, Gujarat, India
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Kondo S, Townsend G, Matsuno M. Morphological variation of the maxillary lateral incisor. JAPANESE DENTAL SCIENCE REVIEW 2014. [DOI: 10.1016/j.jdsr.2014.06.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
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40
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Ben-Bassat Y, Babadzhanov D, Brin I, Hazan-Molina H, Aizenbud D. Maturation of teeth adjacent to dental agenesis site. Acta Odontol Scand 2014; 72:516-22. [PMID: 25005625 DOI: 10.3109/00016357.2013.875587] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE The purpose of this study was to evaluate the developmental stage of teeth adjacent to the agenesis site in comparison to their antimeres. MATERIALS AND METHODS Panoramic views of 39 patients with unilateral dental agenesis and 42 normal controls were evaluated. The dental developmental stage (normal or delayed) of the teeth adjacent to the agenesis site was determined for each patient using the Haavikko's method, while the overall dental age was determined by Becker's method. RESULTS No statistically significant difference was found in the developmental stage of teeth adjacent to the agenesis, compared to their antimere and to the same teeth in the normal control group. However, the prevalence of cases with no difference in development was almost double for the tooth distal to the agenesis site compared to the tooth mesial to the agenesis site in the hypodontia group (84.6% distal and 43.6% mesial; p < 0.001) and in the control group (83.3% distal and 52.4% mesial; p < 0.002). In most of the cases the tooth distal to the agenesis site was the 1st permanent molar. CONCLUSIONS (1) No difference was found between the developmental stage of teeth adjacent to the agenesis site and their antimeres. (2) Teeth mesial to the agenesis site showed some delay in development compared to teeth distal to the agenesis site, in this study. (3) The 1st molars, which were in most of the cases the distal adjacent tooth to the site of agenesis, showed developmental stability. (4) Additional longitudinal studies are needed to examine the dental developmental pattern in patients with agenesis.
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Affiliation(s)
- Yocheved Ben-Bassat
- Department of Orthodontics, Hebrew University-Hadassah School of Dental Medicine , Jerusalem , Israel
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Kero D, Kalibovic Govorko D, Vukojevic K, Cubela M, Soljic V, Saraga-Babic M. Expression of cytokeratin 8, vimentin, syndecan-1 and Ki-67 during human tooth development. J Mol Histol 2014; 45:627-40. [PMID: 25120060 DOI: 10.1007/s10735-014-9592-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 08/06/2014] [Indexed: 12/22/2022]
Abstract
Spatio-temporal immunolocalizations of cytokeratin 8 (CK8), vimentin, syndecan-1 and Ki-67 were analyzed in ten human incisors and canine tooth germs between the 7th and 20th developmental weeks. CK8 expression was mild to moderate in the epithelial tooth parts, while it shifted from absent or mild in its mesenchymal parts, but few cells, sparsely distributed throughout the tooth germ, strongly expressed CK8. As development progressed, CK8 expression increased to strong in preameloblasts, while expression of vimentin increased to moderate in the epithelial and mesenchymal tooth parts, particularly in the dental papilla and sac. Co-expression of CK8 and vimentin was observed in some parts of the tooth germ, and was increasing in the differentiating preameloblasts and preodontoblasts. Syndecan-1 showed characteristic shift of expression from epithelial to mesenchymal tooth parts, being particularly strong in dental papilla, sac and cervical loops, while co-expression of Ki-67/syndecan-1 was strong in the dental papilla. Our study demonstrated spatio-temporal expression and restricted co-expression of the investigated markers, indicating participation of CK8 and vimentin in cell proliferation and migration, and differentiation of preodontoblasts and preameloblasts. Our data also suggest involvement of syndecan-1 in morphogenesis of the developing tooth crown and cervical loops, and together with CK8 and vimentin in differentiation of preameloblasts and preodontoblasts.
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Affiliation(s)
- D Kero
- School of Dental Medicine, University of Split, Soltanska 2, 21000, Split, Croatia
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Reuland-Bosma W, Reuland MC, Bronkhorst E. Distribution of permanent canine agenesis in Down syndrome: 15 cases from a Centre for Special Care Dentistry. SPECIAL CARE IN DENTISTRY 2014; 35:78-82. [PMID: 25081021 DOI: 10.1111/scd.12086] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The purpose of this study was to investigate the distribution of permanent canine agenesis in subjects with Down syndrome (DS). Subjects with canine agenesis were determined by means of panoramic radiographs from 150 DS subjects attending a center for special care dentistry. Our results confirm the high prevalence of agenetic canines in DS (21 canines, 14%). We found specific effects on the distribution both of phenotype and of location (jaw). In subjects with a mild expression of hypodontia (phenotype nonoligodontia) agenetic canines primarily occurred in the mandibula, whereas in subjects with severe hypodontia (phenotype oligodontia) agenetic canines virtually only occurred in the maxilla. In both phenotypes cooccurrence of an agenetic lateral incisor with an agenetic canine was observed in the maxilla. It was striking that canine agenesis in the mandibula did not cooccur with agenesis of other teeth. These results can be important for treatment planning.
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Affiliation(s)
- Wimke Reuland-Bosma
- Centre for Special Care Dentistry, CBT Rijnmond in Rotterdam, The Netherlands
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Redwood C, Townsend GC, Ghabriel M, Brook AH. Under your nose: a rare finding during dissection provides insights into maxillary supernumerary teeth. Aust Dent J 2014; 59:379-85. [PMID: 24861905 DOI: 10.1111/adj.12194] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/24/2013] [Indexed: 11/29/2022]
Abstract
BACKGROUND A supernumerary tooth was found during anatomical dissection. The position of this tooth, still impacted in the maxilla, and the associated pathology make this a rare case. METHODS During dissection by dental students of the sagittally-sectioned head of a cadaver, a supernumerary tooth was identified in the mid-palatal area. Further dissection revealed a swelling with a thin bony covering related to the crown of the tooth. The maxilla was removed en bloc and radiographic examination, CT scanning, electron microscopy and histology were undertaken. RESULTS The tooth had a crenulated occlusal surface and a single root. It was 25 mm posterior to the root apex of the permanent upper central incisor. The swelling, confirmed by radiographs and CT imaging to be associated with the crown, occupied approximately one-third of the maxillary sinus. The 3D shape of the cystic lesion was visualized by a composite digital movie. CONCLUSIONS The crown form, position of the tooth and the associated dentigerous cyst suggested it was a palatally developing supernumerary premolar which had been displaced to the palatal midline by the expanding cyst. This rare case highlights the learning and teaching opportunities available during dissection, showing important variations in both development and clinical anatomy.
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Affiliation(s)
- C Redwood
- Centre for Orofacial Research and Learning, School of Dentistry, The University of Adelaide, South Australia
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44
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Al-Shahrani I, Dirks W, Jepson N, Khalaf K. 3D-Geomorphometrics tooth shape analysis in hypodontia. Front Physiol 2014; 5:154. [PMID: 24795649 PMCID: PMC4006061 DOI: 10.3389/fphys.2014.00154] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Accepted: 03/31/2014] [Indexed: 11/14/2022] Open
Abstract
Assessment of tooth morphology is an important part of the diagnosis and management of hypodontia patients. Several techniques have been used to analyze tooth form in hypodontia patients and these have shown smaller tooth dimensions and anomalous tooth shapes in patients with hypodontia when compared with controls. However, previous studies have mainly used 2D images and provided limited information. In the present study, 3D surface-imaging and statistical shape analysis were used to evaluate tooth form differences between hypodontia and control patients. Eighteen anatomical landmarks were recorded on the clinical crown of the lower left first permanent molar of 3D scanned study models of hypodontia and control subjects. The study sample group comprised of 120 hypodontia patients (40 mild, 40 moderate, and 40 severe hypodontia patients) and 40 age- and sex-matched controls. Procrustes coordinates were utilized to scale and superimpose the landmark coordinate data and then were subjected to principal component analysis (PCA). Subsequently, differences in shape as well as size were tested statistically using allometric analysis and MANOVA. Significant interaction was found between the two factor variables “group” and “sex” (p < 0.002). Overall expected accuracies were 66 and 56% for females and males, respectively, in the cross-validated discriminant-analysis using the first 20 PCs. Hypodontia groups showed significant shape differences compared with the control subjects (p < 0.0001). Significant differences in tooth crown shape were also found between sexes (p < 0.0001) within groups. Furthermore, the degree of variation in tooth form was proportional to the degree of the severity of the hypodontia. Thus, quantitative measurement of tooth shape in hypodontia patients may enhance the multidisciplinary management of those patients.
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Affiliation(s)
- Ibrahim Al-Shahrani
- Division of Orthodontics, Department of Preventive Dental Sciences, College of Dentistry, King Khalid University Abha, Saudi Arabia
| | - Wendy Dirks
- Department of Orthodontics, Centre for Oral Health Research, School of Dental Sciences, Newcastle University Newcastle upon Tyne, UK
| | - Nicholas Jepson
- Department of Orthodontics, Centre for Oral Health Research, School of Dental Sciences, Newcastle University Newcastle upon Tyne, UK
| | - Khaled Khalaf
- Dental School and Hospital, The University of Aberdeen Aberdeen, UK
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Abstract
BACKGROUND Children often receive inferior alveolar nerve blocks (IANBs) when their third molars are just beginning to develop. The location of the third-molar follicle is close to where the needle penetrates during an IANB. The authors examined the possible association between IANBs and missing third molars. METHODS The authors examined 439 potential sites of third-molar development for evidence of third-molar follicles on panoramic radiographs of randomly selected children 7 years and older. The authors conducted a statistical comparison of the incidence of missing third-molar follicles in a control group of children who had no history of receiving IANBs with children in a test group who had a definitive history of receiving IANBs by means of generalized estimating equations. RESULTS The authors found a statistically significant greater incidence of missing third-molar follicles in mandibular quadrants that had a definitive history of receiving IANBs compared with mandibular quadrants that had no history of receiving IANB. CONCLUSION IANBs administered to young children when the third-molar tooth bud is immature may stop third-molar development. Owing to the significant clinical implications, further research is needed to verify these results. PRACTICAL IMPLICATIONS Dentists inadvertently may be stopping the development of third molars when administering IANBs to children.
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Brook AH, Jernvall J, Smith RN, Hughes TE, Townsend GC. The dentition: the outcomes of morphogenesis leading to variations of tooth number, size and shape. Aust Dent J 2014; 59 Suppl 1:131-42. [DOI: 10.1111/adj.12160] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- AH Brook
- School of Dentistry; The University of Adelaide; South Australia Australia
- Institute of Dentistry; Queen Mary University of London; United Kingdom
| | - J Jernvall
- Institute of Biotechnology; University of Helsinki; Finland
| | - RN Smith
- School of Dentistry; University of Liverpool; Liverpool United Kingdom
| | - TE Hughes
- School of Dentistry; The University of Adelaide; South Australia Australia
| | - GC Townsend
- School of Dentistry; The University of Adelaide; South Australia Australia
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Brook AH, O'Donnell MB, Hone A, Hart E, Hughes TE, Smith RN, Townsend GC. General and craniofacial development are complex adaptive processes influenced by diversity. Aust Dent J 2014; 59 Suppl 1:13-22. [PMID: 24617813 DOI: 10.1111/adj.12158] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Complex systems are present in such diverse areas as social systems, economies, ecosystems and biology and, therefore, are highly relevant to dental research, education and practice. A Complex Adaptive System in biological development is a dynamic process in which, from interacting components at a lower level, higher level phenomena and structures emerge. Diversity makes substantial contributions to the performance of complex adaptive systems. It enhances the robustness of the process, allowing multiple responses to external stimuli as well as internal changes. From diversity comes variation in outcome and the possibility of major change; outliers in the distribution enhance the tipping points. The development of the dentition is a valuable, accessible model with extensive and reliable databases for investigating the role of complex adaptive systems in craniofacial and general development. The general characteristics of such systems are seen during tooth development: self-organization; bottom-up emergence; multitasking; self-adaptation; variation; tipping points; critical phases; and robustness. Dental findings are compatible with the Random Network Model, the Threshold Model and also with the Scale Free Network Model which has a Power Law distribution. In addition, dental development shows the characteristics of Modularity and Clustering to form Hierarchical Networks. The interactions between the genes (nodes) demonstrate Small World phenomena, Subgraph Motifs and Gene Regulatory Networks. Genetic mechanisms are involved in the creation and evolution of variation during development. The genetic factors interact with epigenetic and environmental factors at the molecular level and form complex networks within the cells. From these interactions emerge the higher level tissues, tooth germs and mineralized teeth. Approaching development in this way allows investigation of why there can be variations in phenotypes from identical genotypes; the phenotype is the outcome of perturbations in the cellular systems and networks, as well as of the genotype. Understanding and applying complexity theory will bring about substantial advances not only in dental research and education but also in the organization and delivery of oral health care.
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Affiliation(s)
- A H Brook
- School of Dentistry, The University of Adelaide, South Australia, Australia; Institute of Dentistry, Queen Mary University of London, United Kingdom
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Hasegawa Y, Amarsaikhan B, Chinvipas N, Tsukada SI, Terada K, Uzuka S, Miyashita W, Iguchi S, Arai K, Kageyama I, Nakahara S. Comparison of mesiodistal tooth crown diameters and arch dimensions between modern Mongolians and Japanese. Odontology 2013; 102:167-75. [DOI: 10.1007/s10266-013-0130-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 07/14/2013] [Indexed: 11/28/2022]
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49
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Polychronis G, Christou P, Mavragani M, Halazonetis DJ. Geometric morphometric 3D shape analysis and covariation of human mandibular and maxillary first molars. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2013; 152:186-96. [PMID: 24009105 DOI: 10.1002/ajpa.22340] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 06/20/2013] [Accepted: 06/20/2013] [Indexed: 12/31/2022]
Abstract
Dental casts of 160 Greek subjects (80 males, 80 females) were scanned by a structured-light scanner. The upper and lower right first molar occlusal surface 3D meshes were processed using geometric morphometric methods. A total of 265 and 274 curve and surface sliding semilandmarks were placed on the upper and lower molar surfaces, respectively. Principal component analysis and partial least square analysis were performed to assess shape parameters. Molars tended to vary between an elongated and a more square form. The first two principal components (PCs), comprising almost 1/3 of molar shape variation, were related to mesiodistal-buccolingual ratios and relative cusp position. Distal cusps displayed the greatest shape variability. Molars of males were larger than those of females (2.8 and 3.2% for upper and lower molars respectively), but no shape dimorphism was observed. Upper and lower molar sizes were significantly correlated (r(2) = 0.689). Allometry was observed for both teeth. Larger lower molars were associated with shorter cusps, expansion of the distal cusp, and constriction of the mesial cusps (predicted variance 3.25%). Upper molars displayed weaker allometry (predicted variance 1.59%). Upper and lower molar shape covariation proved significant (RV = 17.26%, P < 0.0001). The main parameter of molar covariation in partial least square axis 1, contributing to 30% of total covariation, was cusp height, in contrast to the primary variability traits exhibited by PC1 and PC2. The aim of this study was to evaluate shape variation and covariation, including allometry and sexual dimorphism, of maxillary and mandibular first permanent molar occlusal surfaces.
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Affiliation(s)
- Georgios Polychronis
- Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, Athens, 11527, Greece
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50
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Practical relevance of pattern uniqueness in forensic science. Forensic Sci Int 2013; 231:403.e1-16. [DOI: 10.1016/j.forsciint.2013.05.028] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Revised: 03/10/2013] [Accepted: 05/16/2013] [Indexed: 11/22/2022]
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