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McCrary T, Hughes T, Brook AH, Paul KS. Mirror, mirror? An evaluation of identical twin mirroring in tooth crown morphology. Anat Rec (Hoboken) 2024; 307:3102-3119. [PMID: 38372073 DOI: 10.1002/ar.25408] [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: 12/30/2023] [Revised: 01/30/2024] [Accepted: 01/31/2024] [Indexed: 02/20/2024]
Abstract
It has been estimated that 25% of monozygotic ("identical") twin pairs exhibit reverse asymmetry (RA) or "mirroring" of minor anatomical features as a result of delayed zygote division. Here, we examine whether identical twin mirroring accounts for patterns of dental asymmetry in a sample of monozygotic and dizygotic ("fraternal") twins. We focus on crown morphology to approach the following question: is there an association between dental RA frequency and twin type suggestive of the presence of mirror image twins in our sample? Data were collected from 208 deciduous and 196 permanent dentitions of participants of the University of Adelaide Twin Study using Arizona State University Dental Anthropology System standards. RA frequencies were compared across morphological complexes (deciduous, permanent), twin types (monozygotic, dizygotic), and traits. Fisher's exact tests were performed to formally evaluate the association between twin type and dental RA. Across the entire dataset, RA rates failed to exceed 8% for any twin type. In monozygotic twins, deciduous mirroring totaled 5.3% of observed cases, while permanent mirroring totaled 7.8% of observed cases. We found no statistically significant association between RA and twin type for any morphological character (p-value range: 0.07-1.00). Our results suggest the timing of monozygotic twin division does not explain the structure of asymmetry for our morphology dataset and that published estimates of identical twin mirroring rates may be inflated or contingent upon phenotype. Instead, rates reported for this sample more closely align with the proposed etiology of this condition.
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Affiliation(s)
- Tess McCrary
- Department of Anthropology, University of Arkansas, Fayetteville, Arkansas, USA
- University of Tennessee Health Science Center, College of Dentistry, Memphis, Tennessee, USA
| | - Toby Hughes
- Adelaide Dental School, The University of Adelaide, Adelaide, SA, Australia
| | - Alan H Brook
- Adelaide Dental School, The University of Adelaide, Adelaide, SA, Australia
- Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom
| | - Kathleen S Paul
- Department of Anthropology, University of Arkansas, Fayetteville, Arkansas, USA
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Šidlauskienė M, Šidlauskas M, Šidlauskas A, Juzėnas S, Lopatienė K. Heritability of cephalometric variables of airway morphology in twins with completed active growth. BMC Oral Health 2023; 23:244. [PMID: 37106360 PMCID: PMC10134508 DOI: 10.1186/s12903-023-02919-x] [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: 12/16/2022] [Accepted: 03/28/2023] [Indexed: 04/29/2023] Open
Abstract
BACKGROUND The interplay between genetic and environmental impacts on dental and facial morphology has been widely analyzed, but little is known about their relative contributions to airway morphology. The aim of this study was to evaluate the genetic and environmental influences on the cephalometric variables of airway morphology in a group of postpubertal twins with completed craniofacial growth. MATERIALS AND METHODS The materials comprised lateral head cephalograms of 94 pairs of twins (50 monozygotic, 44 dizygotic) with completed craniofacial growth. Zygosity was determined using 15 specific DNA markers. The computerized cephalometric analysis included 22 craniofacial, hyoideal, pharyngeal structural linear and angular variables. Genetic analysis and heritability estimation were performed using maximum likelihood genetic structural equation modeling (GSEM). Principal component analysis (PCA) was used to assess the correlations between cephalometric measurement variables. RESULTS Upper airway dimensions showed moderate to high genetic determination (SPPW-SPP and U-MPW: a2 = 0.64 and 0.5, respectively). Lower airway parameters showed only common and specific environmental determination (PPW-TPP a2 = 0.24, e2 = 0.38; LPW-V c2 = 0.2, e2 = 0.63; PCV-AH c2 = 0.47, e2 = 0.28). The relationship between the maxilla and the hyoid bone (for variables PNS-AH, ANS-AH d2 = 0.9, 0.92, respectively) showed very strong additive genetic determination. The size of the soft palate was affected by additive and dominant genes. Its length (SPL) was strongly influenced by dominant genes, while its width (SPW) showed a moderate additive genetic influence. Owing to correlations in the behavior of variables, the data could be expressed in 5 principal components that jointly explained 36.8% of the total variance. CONCLUSIONS The dimensions of the upper airway are strongly determined by genes, while the parameters of the lower airway depend mainly on environmental factors. TRIAL REGISTRATION The protocol has been approved by the Kaunas Regional Ethical Committee (No. BE - 2-41., May 13, 2020).
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Affiliation(s)
- Monika Šidlauskienė
- Department of Orthodontics, Faculty of Medicine, Lithuanian University of Health Sciences, Eivenių 2, Kaunas, LT-50161, Lithuania.
- Clinic of Orthodontics, Medical Academy, Lithuanian University of Health Sciences, J. Lukšos-Daumanto str. 6, Kaunas, LT-50106, Lithuania.
| | - Mantas Šidlauskas
- Department of Orthodontics, Faculty of Medicine, Lithuanian University of Health Sciences, Eivenių 2, Kaunas, LT-50161, Lithuania
| | - Antanas Šidlauskas
- Department of Orthodontics, Faculty of Medicine, Lithuanian University of Health Sciences, Eivenių 2, Kaunas, LT-50161, Lithuania
| | - Simonas Juzėnas
- Institute of Digestive Research, Faculty of Medicine, Lithuanian University of Health Sciences, Eivenių 2, Kaunas, LT-50161, Lithuania
| | - Kristina Lopatienė
- Department of Orthodontics, Faculty of Medicine, Lithuanian University of Health Sciences, Eivenių 2, Kaunas, LT-50161, Lithuania
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Hersberger-Zurfluh MA, Papageorgiou SN, Motro M, Kantarci A, Will LA, Eliades T. Genetic and environmental components of vertical growth in mono- and dizygotic twins up to 15-18 years of age. Angle Orthod 2021; 91:384-390. [PMID: 33523142 DOI: 10.2319/060520-515.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 12/01/2020] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVES To determine the additive genetic and environmental contributions to the vertical growth of craniofacial structures. MATERIALS AND METHODS The sample consisted of 64 untreated monozygotic (44 male, 20 female) and 61 untreated dizygotic twins (32 male, 29 female). Lateral cephalograms taken at 15 and 18 years of age were traced to analyze the sella-nasion-nasal line angle (SN-NL), nasal line-mandibular line angle (ML-NL), sella-nasion-mandibular line angle (SN-ML), sella-nasion-sella-gnathion angle (Y-axis), posterior face height/anterior face height (PFH/AFH), and lower anterior face height/anterior face height (LAFH/AFH). The genetic and environmental components of variance were analyzed with structural equation modeling for multilevel mixed effects. RESULTS At 15 years of age, strong dominant genetic control was seen for NL-ML (81%), LAFH/AFH (73%), and Y-axis (57%), whereas strong additive genetic components were found for PFH/AFH (78%), SN-NL (58%), and SN-ML (57%). Unique environmental factors accounted for 18-42% of observed variance, with SN-NL being affected the most (42%). At 18 years of age, only LAFH/AFH (86%) was under strong dominant genetic control, whereas the remainder were under additive genetic influence. The sole exception was SN-NL, which changed from additive to unique environmental influence. CONCLUSIONS Either additive or dominant genetic components were found at 15 or 18 years of age for most vertical variables. Environmental factors accounted for about 10-40%, with SN-NL being mostly affected.
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Neela PK, Atteeri A, Mamillapalli PK, Sesham VM, Keesara S, Chandra J, Monica U, Mohan V. Genetics of Dentofacial and Orthodontic Abnormalities. Glob Med Genet 2021; 7:95-100. [PMID: 33693441 PMCID: PMC7938796 DOI: 10.1055/s-0040-1722303] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/30/2022] Open
Abstract
The development of craniofacial complex and dental structures is a complex and delicate process guided by specific genetic mechanisms. Genetic and environmental factors can influence the execution of these mechanisms and result in abnormalities. An insight into the mechanisms and genes involved in the development of orofacial and dental structures has gradually gained by pedigree analysis of families and twin studies as well as experimental studies on vertebrate models. The development of novel treatment techniques depends on in-depth knowledge of the various molecular or cellular processes and genes involved in the development of the orofacial complex. This review article focuses on the role of genes in the development of nonsyndromic orofacial, dentofacial variations, malocclusions, excluding cleft lip palate, and the advancements in the field of molecular genetics and its application to obtain better treatment outcomes.
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Affiliation(s)
- Praveen Kumar Neela
- Department of Orthodontics, Kamineni Institute of Dental Sciences, Narketpally, India
| | - Anjana Atteeri
- Department of Orthodontics, Kamineni Institute of Dental Sciences, Narketpally, India
| | | | - Vasu Murthy Sesham
- Department of Orthodontics, Kamineni Institute of Dental Sciences, Narketpally, India
| | - Sreekanth Keesara
- Department of Orthodontics, Kamineni Institute of Dental Sciences, Narketpally, India
| | - Jaya Chandra
- Department of Orthodontics, Kamineni Institute of Dental Sciences, Narketpally, India
| | - Udayini Monica
- Department of Orthodontics, Kamineni Institute of Dental Sciences, Narketpally, India
| | - Vasavi Mohan
- Department of Genetics and Molecular Medicine, Vasavi Medical and Research Centre, Hyderabad, Telangana, India
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Van Dyck J, Cadenas de Llano-Pérula M, Willems G, Verdonck A. Dental development in cleft lip and palate patients: A systematic review. Forensic Sci Int 2019; 300:63-74. [DOI: 10.1016/j.forsciint.2019.04.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 02/14/2019] [Accepted: 04/09/2019] [Indexed: 11/30/2022]
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Filipović GL, Stojanović NM, Jovanović ID, Randjelović PJ, Ilić IR, Djordjević NS, Radulović NS. Differences in Angular Photogrammetric Soft-Tissue Facial Characteristics among Parents and Their Offspring. ACTA ACUST UNITED AC 2019; 55:medicina55050197. [PMID: 31126130 PMCID: PMC6571664 DOI: 10.3390/medicina55050197] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 04/02/2019] [Accepted: 05/17/2019] [Indexed: 11/16/2022]
Abstract
Background and objectives: The objective of this study was to determine if the angular photogrammetric analysis of soft-tissue characteristics can determine similarities between parents and their offspring in the Serbian population. Materials and Methods: A total of 15 families (52 participants) met the participation criteria of this study and their facial profile images were analyzed using the ImageJ software. Subjects were divided into groups of mothers and fathers and four groups of children (divided according to their age and gender). In total, twelve angular measurements were made on the standardized digital images of the profiles of the participants and the obtained data were compared using one-way ANOVA. Results: The obtained results showed that there were statistically significant differences in the values of the nasal and cervicomental angles, as well as the angle of the total facial convexity, between the group of fathers, on one side, and groups of male/female children, on the other. Conclusions: This work represents the first photogrammetric analysis of facial soft-tissue characteristics of children and adults in the Serbian population. The data suggest that there are much more similarities between the facial soft-tissue angles of fathers and their male offspring. Furthermore, mothers tend to have statistically insignificant differences in angle sizes, compared to both male and female offspring.
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Affiliation(s)
- Gordana Lj Filipović
- Department of Orthodontics, Dental Clinic, Faculty of Medicine, University of Niš, Zorana Đinđića 81, 18000 Niš, Serbia.
| | - Nikola M Stojanović
- Faculty of Medicine, University of Niš, Zorana Đinđića 81, 18000 Niš, Serbia.
| | - Ivan D Jovanović
- Department of Anatomy, Faculty of Medicine, University of Niš, Zorana Đinđića 81, 18000 Niš, Serbia.
| | - Pavle J Randjelović
- Department of Physiology, Faculty of Medicine, University of Niš, Zorana Đinđića 81, 18000 Niš, Serbia.
| | - Ivan R Ilić
- Institute of Pathology, Faculty of Medicine, University of Niš, Zorana Đinđića 81, 18000 Niš, Serbia.
| | - Nadica S Djordjević
- Dental Clinic, Faculty of Medicine, University of Priština Kosovska Mitrovica, Anri Dinana bb, 38220 Kosovska Mitrovica, Serbia.
| | - Niko S Radulović
- Department of Chemistry, Faculty of Sciences and Mathematics, University of Niš, Višegradska 33, 18000 Niš, Serbia.
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Même patrimoine génétique et pourtant différents : étude de cas comparative de jumeaux. Int Orthod 2017; 15:483-497. [DOI: 10.1016/j.ortho.2017.06.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Mas C, Frapier L. A genetic heritage; the same yet different: A comparative study in twins. Int Orthod 2017; 15:483-497. [PMID: 28838757 DOI: 10.1016/j.ortho.2017.06.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Since the 19th century, and in every field of medicine, monozygotic twins have been studied to assess the involvement of genetic and environmental factors in phenotypic expression. The phenotype/genotype relationship remains the leading problem in contemporary biology. In dentofacial orthopedics, this relationship is of relevance in the three-dimensional approach to the face, in both diagnosis and treatment. The present study of two monozygotic twins presenting skeletal class III malocclusions which were genetic yet different is a clear illustration of the interaction of genotype and epigenetic factors with environmental influences. We will demonstrate that treatment can reduce phenotypic differences.
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Affiliation(s)
- Catherine Mas
- Département d'ODF, UFR Odontologie de Montpellier, 545, avenue du Pr-Jean-Louis-Viala, 34080 Montpellier, France.
| | - Laure Frapier
- Département d'ODF, UFR Odontologie de Montpellier, 545, avenue du Pr-Jean-Louis-Viala, 34080 Montpellier, France
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9
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Carlson DS. Evolving concepts of heredity and genetics in orthodontics. Am J Orthod Dentofacial Orthop 2016; 148:922-38. [PMID: 26672698 DOI: 10.1016/j.ajodo.2015.09.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 09/01/2015] [Accepted: 09/01/2015] [Indexed: 11/16/2022]
Abstract
The field of genetics emerged from the study of heredity early in the 20th century. Since that time, genetics has progressed through a series of defined eras based on a number of major conceptual and technical advances. Orthodontics also progressed through a series of conceptual stages over the past 100 years based in part on the ongoing and often circular debate about the relative importance of heredity (nature) and the local environment (nurture) in the etiology and treatment of malocclusion and dentofacial deformities. During the past 20 years, significant advancements in understanding the genomic basis of craniofacial development and the gene variants associated with dentofacial deformities have resulted in a convergence of the principles and concepts in genetics and in orthodontics that will lead to significant advancement of orthodontic treatments. Fundamental concepts from genetics and applied translational research in orthodontics provide a foundation for a new emphasis on precision orthodontics, which will establish a modern genomic basis for major improvements in the treatment of malocclusion and dentofacial deformities as well as many other areas of concern to orthodontists through the assessment of gene variants on a patient-by-patient basis.
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Affiliation(s)
- David S Carlson
- Regents Professor, Department of Biomedical Sciences, Texas A&M Baylor College of Dentistry, Texas A&M Health Science Center, Dallas, Tex.
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10
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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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11
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Cho C, Louie K, Maawadh A, Gerstner GE. Comparisons of chewing rhythm, craniomandibular morphology, body mass and height between mothers and their biological daughters. Arch Oral Biol 2015; 60:1667-74. [PMID: 26363460 DOI: 10.1016/j.archoralbio.2015.08.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 07/27/2015] [Accepted: 08/08/2015] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To study and compare the relationships between mean chewing cycle duration, selected cephalometric variables representing mandibular length, face height, etc., measured in women and in their teenage or young-adult biological daughters. DESIGN Daughters were recruited from local high schools and the University of Michigan School of Dentistry. Selection criteria included healthy females with full dentition, 1st molar occlusion, no active orthodontics, no medical conditions nor medication use that could interfere with normal masticatory motor function. Mothers had to be biologically related to their daughters. All data were obtained in the School of Dentistry. Measurements obtained from lateral cephalograms included: two "jaw length" measures, condylion-gnathion and gonion-gnathion, and four measures of facial profile including lower anterior face height, and angles sella-nasion-A point (SNA), sella-nasion-B point (SNB) and A point-nasion-B point (ANB). Mean cycle duration was calculated from 60 continuous chewing cycles, where a cycle was defined as the time between two successive maximum jaw openings in the vertical dimension. Other variables included subject height and weight. Linear and logistic regression analyses were used to evaluate the mother-daughter relationships and to study the relationships between cephalometric variables and chewing cycle duration. RESULTS Height, weight, Co-Gn and Go-Gn were significantly correlated between mother-daughter pairs; however, mean cycle duration was not (r(2)=0.015). Mean cycle duration was positively correlated with ANB and height in mothers, but negatively correlated with Co-Gn in daughters. CONCLUSIONS Chewing rate is not correlated between mothers and daughters in humans.
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Affiliation(s)
- Catherine Cho
- Department of Orthodontics and Pediatric Dentistry, School of Dentistry, University of Michigan, Ann Arbor, MI 48109-1078, USA
| | - Ke'ale Louie
- Oral Health Sciences PhD Program School of Dentistry, University of Michigan, Ann Arbor, MI 48109-1078, USA
| | - Ahmed Maawadh
- Department of Cariology, Restorative Sciences and Endodontics, School of Dentistry, University of Michigan, Ann Arbor, MI 48109-1078, USA
| | - Geoffrey E Gerstner
- Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI 48109-1078, USA.
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13
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Hughes TE, Townsend GC, Pinkerton SK, Bockmann MR, Seow WK, Brook AH, Richards LC, Mihailidis S, Ranjitkar S, Lekkas D. The teeth and faces of twins: providing insights into dentofacial development and oral health for practising oral health professionals. Aust Dent J 2013; 59 Suppl 1:101-16. [DOI: 10.1111/adj.12101] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- TE Hughes
- School of Dentistry; The University of Adelaide; South Australia Australia
| | - GC Townsend
- School of Dentistry; The University of Adelaide; South Australia Australia
| | - SK Pinkerton
- School of Dentistry; The University of Adelaide; South Australia Australia
| | - MR Bockmann
- School of Dentistry; The University of Adelaide; South Australia Australia
| | - WK Seow
- School of Dentistry; The University of Queensland; Brisbane Australia
| | - AH Brook
- School of Dentistry; The University of Adelaide; South Australia Australia
- Institute of Dentistry; Queen Mary University of London; United Kingdom
| | - LC Richards
- School of Dentistry; The University of Adelaide; South Australia Australia
| | - S Mihailidis
- School of Dentistry; The University of Adelaide; South Australia Australia
| | - S Ranjitkar
- School of Dentistry; The University of Adelaide; South Australia Australia
| | - D Lekkas
- School of Dentistry; The University of Adelaide; South Australia Australia
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15
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Oh J, Wang CJ, Poole M, Kim E, Davis RC, Nishimura I, Pae EK. A genome segment on mouse chromosome 12 determines maxillary growth. J Dent Res 2008; 86:1203-6. [PMID: 18037656 DOI: 10.1177/154405910708601212] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The primary and modifier genes that regulate normal maxillofacial development are unknown. Previous quantitative trait locus (QTL) analyses using the F2 progeny of 2 mouse strains, DBA/2J (short snout/wide face) and C57BL/6J (long snout/narrow face), revealed a significant logarithm-of-odds (LOD) score for snout length on mouse chromosome 12 at 44 centimorgan (cM). We further sought to validate this locus contributing to anterior-posterior dimensions of the upper mid-face at the D12Mit7 marker in a 44-centimorgan portion of chromosome 12. Congenic mice carrying introgressed DNA from DBA/2J on a C57BL/6J background were selected for submental vertex cephalometric imaging. Results confirmed QTLs, determining that short snout length (P < 0.05) and face width relative to snout length (P < 0.01) were present in the 44-cM region of chromosome 12. We conclude that one or more genes contributing to the shape of the maxillary complex are located near 44 cM of mouse chromosome 12.
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Affiliation(s)
- J Oh
- Section of Orthodontics, UCLA School of Dentistry, 43-091 Center for the Health Sciences, Box 951668, Los Angeles, CA 90095-1668, USA
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Shino T, Kawabata K, Nojima K, Nishii Y, Sueishi K, Yamaguchi H. Morphological study on quadruplets by cephalometric and model analyses. THE BULLETIN OF TOKYO DENTAL COLLEGE 2007; 48:19-26. [PMID: 17721063 DOI: 10.2209/tdcpublication.48.19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Clarifying the genetic factors involved in maxillofacial growth and development is very important in orthodontic treatment planning and prognosis. However, few dental studies have examined multiple births. The present orthodontic evaluation was conducted using orthodontic data from a set of quadruplets. Orthodontic evaluation was performed on a set of quadruplets (1 girl and 3 boys) aged 9 years and 7 months at the initial visit. Although all 4 children weighed only about 1,400 g each at birth, height and body weight subsequently normalized. Mean skeletal age of the quadruplets was 10 years and 2 months, about 6 months ahead of their calendar age. In all 4 children, facial profile was mostly symmetrical and convex. Intraoral findings showed a Hellman's dental age of IIIA, together with spacing of the upper anterior teeth. Both overbite and overjet were 5-7 mm, and mesial step of the terminal plane was noted. Model analysis showed that tooth materials were on the large side, while arch width was narrow. Cephalometric analysis revealed that the ANB of the first- and fourth-born children was 6 degrees , and skeletal maxillary protrusion due to mandibular retrusion was diagnosed. The second- and thirdborn children exhibited no marked skeletal abnormalities.
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Affiliation(s)
- Tamami Shino
- Department of Clinical Oral Health Science, Tokyo Dental College, Mihama-ku, Chiba, Japan.
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Cohen-Levy J, Kamoun-Goldrat AS, Simon Y, Lautrou A. [Twins and the heritability of dentofacial phenotype]. Orthod Fr 2007; 78:69-77. [PMID: 17571534 DOI: 10.1051/orthodfr:2007004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
In orthodontics and dentofacial orthopaedics, where genetic and environmental factors interpenetrate from the early stages of development, the clinician tries to determine how mechanics could influence patient's growth pattern. Comparing monozygotic and dizygotic twins, in their similarities and their differences, gives some answers... but raises some questions too. In this article, we gather some clinical studies and case reports, on diagnosis and treatment aspects of malocclusions.
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Affiliation(s)
- Julia Cohen-Levy
- Faculté de chirurgie dentaire, Université Paris VII, 5 rue GaranciBre, 75006 Paris, France.
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Baydaş B, Erdem A, Yavuz I, Ceylan I. Heritability of facial proportions and soft-tissue profile characteristics in Turkish Anatolian siblings. Am J Orthod Dentofacial Orthop 2007; 131:504-9. [PMID: 17418717 DOI: 10.1016/j.ajodo.2005.05.055] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2005] [Revised: 05/01/2005] [Accepted: 05/01/2005] [Indexed: 11/29/2022]
Abstract
INTRODUCTION The purpose of this study was to determine the possible effects of genetic factors on facial proportions and soft-tissue profile characteristics in Turkish Anatolian siblings. METHODS The material consisted of lateral and posteroanterior cephalometric head radiographs of 138 siblings (70 women, 68 men) living 15 years or more in the province of Erzurum in eastern Turkey. The subjects were required to have completed their pubertal growth spurts and to have received no previous orthodontic or prosthodontic treatment. The heritability assessments of craniofacial and soft-tissue measurements were undertaken according to narrow-sense heritability. For the calculation and evaluation of heritability estimate values, the mixed-model least-squared and maximum likelihood computer program model type II was used for statistical analysis. RESULTS According to the narrow-sense heritability estimate values, the measurements of total depth index, soft-tissue chin thickness, soft-tissue facial angle, Merrifield angle, and Holdaway angle showed the highest heritability coefficients (P <.001). Total height index, anterior height index, facial width index, upper to lower facial height index, and lower lip-E line measurements demonstrated moderate heritability values (P<.01). The upper depth index had a low but statistically significant heritability value (P <.05). However, no statistically significant heritability coefficient in upper lip-E line measurement was found. CONCLUSIONS Turkish Anatolian siblings have similar facial features regarding facial proportions and soft-tissue measurements.
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Affiliation(s)
- Bülent Baydaş
- Department of Orthodontics, Faculty of Dentistry, Atatürk University, Erzurum, Turkey
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Peng J, Deng H, Cao C, Ishikawa M. Craniofacial morphology in Chinese female twins: a semi-longitudinal cephalometric study. Eur J Orthod 2005; 27:556-61. [PMID: 16257991 DOI: 10.1093/ejo/cji059] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
It would be of benefit to have a better understanding of the relative effects of genetics and environmental factors on craniofacial parameters when undertaking orthodontic therapy and treatment planning. However, there is a lack of such information in pre-adolescents. The aim of this study was to verify the degree of genetic and environmental contribution to the growth of the facial skeleton in twins aged 6 to 12 years. The material comprised the lateral cephalograms of 89 pairs of female twins in Beijing, China, of whom 61 pairs were diagnosed by DNA analysis as monozygotic (MZ) and 28 pairs as dizygotic (DZ). Four main groups (with a starting age of 6, 7, 9 and 11 years) were studied in a semi-longitudinal manner, with a sub-group further investigated for 2-4 consecutive years. The total sample therefore consisted of 183 pairs (MZ 110, DZ 73) aged from 6 to 12 years. The depths of the cranial base, mid and lower face were measured, as well as anterior and posterior face height. A two-tailed t-test showed significant environmental effects on lower face depth (P < 0.01), whilst genetic effects on face height were also significant (P < 0.01). The results suggest that early orthodontic intervention would have a greater influence on the antero-posterior rather than on the vertical plane of growth.
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Affiliation(s)
- Jing Peng
- Department of Pediatric Dentistry, Peking University School of Stomatology, Bejing, China.
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20
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Abstract
Dental casts and oral photographs from a cross-sectional sample of 2092 young North Americans with detailed information on functional lateralities (eyedness, handedness and footedness) were examined to compare the proportions of symmetrical and asymmetrical eruption of the antimeric (left-right, contralateral pair) permanent teeth using a four-grade eruption scale. The proportion of symmetrically erupting antimeric teeth was higher for some teeth in those with non-right-sidedness of the feet and eyes, but not significantly so in the case of handedness. Left-footedness was significantly (95% confidence interval) associated with an increased proportion of symmetrical pairs of the maxillary first molar and mandibular lateral incisor, and non-right-eyedness with an increased proportion of symmetrical eruption and left/right non-balanced proportions of asymmetrical eruption in maxillary central incisors. True right-sidedness (hand, foot and eye) was significantly (P< or =0.05) associated with advanced eruption of the left mandibular first molar. It is suggested that while the timing of antimeric tooth emergence and clinical eruption is primarily programmed before crown mineralization, starting approximately at the 30th gestational week in the case of first permanent molars, symmetrical/asymmetrical tooth emergence and eruption may provide information a posteriori on prenatal and early postnatal growth and development.
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Affiliation(s)
- T Heikkinen
- Department of Oral Development and Orthodontics, Institute of Dentistry, Box 5281, 90014 University of Oulu, Oulu, Finland.
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Langowska-Adamczyk H, Karmańska B. Similar locations of impacted and supernumerary teeth in monozygotic twins: a report of 2 cases. Am J Orthod Dentofacial Orthop 2001; 119:67-70. [PMID: 11174542 DOI: 10.1067/mod.2001.111225] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In this article, the cases of monozygotic twin brothers with similar developmental dental anomalies have been presented. Localization of impacted and supernumerary teeth and synchronous appearance of analogous ailments (leading to third tonsil removal and removal of supernumerary teeth from the anterior maxilla) are discussed. The boys' mother had also been treated for supernumerary teeth during childhood.
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Affiliation(s)
- H Langowska-Adamczyk
- Second Department of Maxillofacial Surgery, Silesian Medical Academy, Katowice, Poland
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22
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Hughes T, Dempsey P, Richards L, Townsend G. Genetic analysis of deciduous tooth size in Australian twins. Arch Oral Biol 2000; 45:997-1004. [PMID: 11000386 DOI: 10.1016/s0003-9969(00)00066-2] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Investigations of permanent dental crown size in twins and family groups indicate a high degree of transmissible control, but little is known about the relative contributions of genetic and environmental factors to variation in size of the deciduous (primary) teeth. Here, maximum mesiodistal and buccolingual crown dimensions of maxillary and mandibular primary teeth were measured from dental models of 602 individuals, including 99 monozygous (MZ) twin pairs, 81 dizygous (DZ) same-sex pairs, 41 DZ opposite-sex pairs, and 160 singletons. Data were subjected to univariate genetic analysis with the structural-equation-modelling package, Mx using the normal assumptions of the twin model. A model incorporating additive genetic (A) and unique environmental (E) variation was found to be the most parsimonious for all tooth-size variables. Estimates of heritability for deciduous crown size ranged from 0.62 to 0.91. This study shows that variation in deciduous crown size has a strong genetic component, similar to that observed in the permanent dentition. Further studies are required to determine whether the underlying genetic mechanisms are the same for both deciduous and permanent teeth.
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Affiliation(s)
- T Hughes
- Dental School, University of Adelaide, 5005, Adelaide, Australia.
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23
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Abstract
This paper reviews past and present applications of quantitative and molecular genetics to dental disorders. Examples are given relating to craniofacial development (including malocclusion), oral supporting tissues (including periodontal diseases) and dental hard tissues (including defects of enamel and dentine as well as dental caries). Future developments and applications to clinical dentistry are discussed. Early investigations confirmed genetic bases to dental caries, periodontal diseases and malocclusion, but research findings have had little impact on clinical practice. The complex multifactorial aetiologies of these conditions, together with methodological problems, have limited progress until recently. Present studies are clarifying previously unrecognized genetic and phenotypic heterogeneities and attempting to unravel the complex interactions between genes and environment by applying new statistical modelling approaches to twin and family data. Linkage studies using highly polymorphic DNA markers are providing a means of locating candidate genes, including quantitative trait loci (QTL). In future, as knowledge increases; it should be possible to implement preventive strategies for those genetically-predisposed individuals who are identified to be at risk.
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Pelsmaekers B, Loos R, Carels C, Derom C, Vlietinck R. The genetic contribution to dental maturation. J Dent Res 1997; 76:1337-40. [PMID: 9207765 DOI: 10.1177/00220345970760070201] [Citation(s) in RCA: 101] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
It has been established in the literature that there is a major genetic impact on tooth size (Potter et al., 1976; Corruccini and Sharma, 1985; Sharma et al., 1985), tooth morphology (Kraus and Furr, 1952; Biggerstaff, 1970), and root formation (Garn et al., 1960; Green and Aszkler, 1970). None of the studies concerning root formation, however, used the more advanced method of path analysis and model fitting to estimate genetic influence. The aim of the present study was to determine the genetic and environmental influence on dental maturation. Dental age scores were determined on panoramic radiographs of 58 pairs of twins--26 monozygotic (MZ) and 32 dizygotic (DZ)--with the method of Demirjian et al. (1973). No mirror-image effect was found between the sides of the same individual or between twin members, so dental maturation seems to be symmetrical for both left and right sides of the mandible. Correlation coefficients were significantly higher in MZ than in DZ twins, which suggests a genetic influence. Model fitting showed that the variation in dental age was best explained by additive genetic influences (A-component) (43%) and by environmental factors common to both twins (C-component) (50%). The specific environment (E-component) added only 8% to the model. The importance of the common environmental factor can be explained by the fact that twins, being raised together, share the same prenatal, natal, and immediate post-natal conditions that are of importance for the formation of the teeth.
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Affiliation(s)
- B Pelsmaekers
- Department of Orthodontics, School of Dentistry, Oral Pathology and Oral Surgery, Faculty of Medicine, Catholic University of Leuven, Belgium
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Dempsey PJ, Townsend GC, Martin NG, Neale MC. Genetic covariance structure of incisor crown size in twins. J Dent Res 1995; 74:1389-98. [PMID: 7560390 DOI: 10.1177/00220345950740071101] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Previous studies of tooth size in twins and their families have suggested a high degree of genetic control, although there have been difficulties separating the various genetic and environmental effects. A genetic analysis of variation in crown size of the permanent incisors of South Australian twins was carried out, with structural equation modeling used to determine the relative contributions of genetic and environmental factors. Maximum mesiodistal crown dimensions of maxillary and mandibular permanent incisors were recorded from dental models of 298 pairs of twins, including 149 monozygous (MZ) and 149 dizygous (DZ) pairs. The analysis revealed that: (i) an adequate fit required additive genetic and unique environmental components; (ii) augmenting the model with non-additive genetic variation did not lead to a significant improvement in fit; (iii) there was evidence of shared environmental influences in the upper central incisors of males; (iv) the additive genetic component constituted a general factor loading on all eight teeth, with group factors loading on antimeric pairs of teeth; (v) unique environmental effects were mostly variable-specific; (vi) most factor loadings on antimeric tooth pairs could be constrained to be equal, indicating a symmetry of genetic and environmental influences between left and right sides; and (vii) estimated heritability of the incisor mesiodistal dimensions varied from 0.81 to 0.91.
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Affiliation(s)
- P J Dempsey
- Department of Dentistry, University of Adelaide, South Australia
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Rudney JD, Michalowicz BS, Krig MA, Kane PK, Pihlstrom BL. Genetic contributions to saliva protein concentrations in adult human twins. Arch Oral Biol 1994; 39:513-7. [PMID: 8067921 DOI: 10.1016/0003-9969(94)90148-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The heritability of saliva protein concentrations was investigated in stored samples of clarified stimulated whole saliva from adult twins participating in a study of periodontal disease genetics. Saliva was obtained from 29 monozygous and 20 dizygous twin pairs. Visits were scheduled so that both twins in a pair donated saliva at the same time of day. Flow rate was determined, and frozen samples later assayed for lactoferrin, lysozyme, secretory IgA, total peroxidase, myeloperoxidase and total protein. Pairs were always assayed together. Within- and between-pair variances were used to estimate twin intraclass correlations. Pearson correlations were used to estimate associations between saliva variables and clinical indices of gingivitis, dental plaque, periodontal attachment loss, and probing depth. Significant genetic contributions to variance were seen for total protein, lactoferrin, and total peroxidase. Total protein showed a significant positive correlation with gingivitis. There were no other correlations with clinical indices, and intraclass correlations for saliva variables did not change after adjustment for gingivitis. Dizygous twin correlations were higher than monozygous twin correlations for flow rate, lysozyme, and secretory IgA. That may be an artefact due to small numbers of pairs. It seems unlikely that a common environmental factor would strongly affect saliva in twins living apart as adults. Present findings, taken as sib correlations, support a genetic contribution to saliva protein concentrations. Problems with the twin model in saliva might be resolved by longitudinal studies of large numbers of twins.
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Affiliation(s)
- J D Rudney
- Department of Oral Science, School of Dentistry, University of Minnesota, Minneapolis 55455
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Sperber GH, Machin GA, Bamforth FJ. Mirror-image dental fusion and discordance in monozygotic twins. AMERICAN JOURNAL OF MEDICAL GENETICS 1994; 51:41-5. [PMID: 8030668 DOI: 10.1002/ajmg.1320510110] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A pair of monozygotic twins had similar but not identical dental anomalies. One twin had fusion of deciduous mandibular lateral incisor and canine on the left, with normal dentition on the right; the co-twin had right mandibular incisor/canine fusion, with aplasia of the lateral incisor on the left. These findings are discussed in the context of the related phenomena of situs inversus, mirror-imaging in twins, and gradients of severity of anomalies in the four copies of the mandibular developmental dental field.
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Affiliation(s)
- G H Sperber
- Department of Oral Biology, University of Alberta, Edmonton, Canada
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