Stephen Richmond

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Verified

Stephen verified their affiliation via an institutional email.

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• BDS, D.Orth, MScD, FDS, PhD, FHEA, Medicinae Doctorem Honoris Causa (RSU)
• Emeritus Professor at Cardiff University

The idea that symmetry in facial traits is associated with attractiveness because it reliably indicates good physiological health, particularly to potential sexual partners, has generated an extensive literature on the evolution of human mate choice. However, large-scale tests of this hypothesis using direct or longitudinal assessments of physiolog...

Background/objectives: To collect the reference values for facial asymmetry in adults using landmark and surface-based three-dimensional analyses and to compare their diagnostic abilities. Materials and methods: Laser scans were taken from 85 British Caucasians, 29 males (23.9±5.7 years, range 19-44) and 56 females (28.1±9.5 years, range 19-54),...

Twin and family studies indicate that the timing of primary tooth eruption is highly heritable, with estimates typically exceeding 80%. To identify variants involved in primary tooth eruption we performed a population based genome-wide association study of 'age at first tooth' and 'number of teeth' using 5998 and 6609 individuals respectively from...

Objective measures of facial movement are important for interventions where surgical repositioning of facial structures can influence soft tissue mobility and include the management of patients with cleft lip, facial nerve palsy and orthognathic surgery. As such, the aim of this study is to present a method for determining the outcome of surgical p...

SUMMARY Respiratory activity may have an influence on craniofacial development and interact with genetic and environmental factors. It has been suggested that certain medical conditions such as asthma have an influence on face shape. The aim of the study is to investigate whether facial shape is different in individuals diagnosed as having asthma c...

Genotype–phenotype (G-P) analyses for complex morphological traits typically utilize simple, predetermined anatomical measures or features derived via unsupervised dimension reduction techniques (e.g. principal component analysis (PCA) or eigen-shapes). Despite the popularity of these approaches, they do not necessarily reveal axes of phenotypic va...

Human craniofacial shape is highly variable yet highly heritable with numerous genetic variants interacting through multiple layers of development. Here, we hypothesize that Mendelian phenotypes represent the extremes of a phenotypic spectrum and, using achondroplasia as an example, we introduce a syndrome-informed phenotyping approach to identify...

Human facial shape, while strongly heritable, involves both genetic and structural complexity, necessitating precise phenotyping for accurate assessment. Common phenotyping strategies include simplifying 3D facial features into univariate traits such as anthropometric measurements (e.g., inter-landmark distances), unsupervised dimensionality reduct...

The aesthetic component (AC) of the Index of Orthodontic Treatment Need (IOTN) is internationally recognized as a reliable and valid method for assessing aesthetic treatment need. The objective of this study is to use artificial intelligence (AI) to automate the AC assessment. A total of 1009 pre-treatment frontal intraoral photos with overjet valu...

Human facial shape, while strongly heritable, involves both genetic and structural complexity, necessitating precise phenotyping for accurate assessment. Common phenotyping strategies include simplifying 3D facial features into univariate traits such as anthropometric measurements (e.g., inter-landmark distances), unsupervised dimensionality reduct...

Human craniofacial shape is highly variable yet highly heritable with genetic variants interacting through multiple layers of development. Here, we hypothesize that Mendelian phenotypes represent the extremes of a phenotypic spectrum and, using achondroplasia as an example, we introduce a syndrome-informed phenotyping approach to identify genomic l...

A genome-wide association study (GWAS) of a complex, multi-dimensional morphological trait, such as the human face, typically relies on predefined and simplified phenotypic measurements, such as inter-landmark distances and angles. These measures are predominantly designed by human experts based on perceived biological or clinical knowledge. To avo...

The aim of this article is to demonstrate the reproducibility of the Wilson-Richmond Categorisation Tool for the assessment of lip morphology. This categorisation system was initially developed as a result of the identification of various morphological features of the vermilion of the lips, following the review of three-dimensional facial scans col...

Objective: To determine the reproducibility and reliability of the Wilson-Richmond categorisation tool in the assessment of lip morphology and to demonstrate its use in a 12-year old Welsh population. Setting and Sample Population: 50 subjects age 12 (27 male and 23 female) of Caucasian origin selected from two large comprehensive schools in South...

Objective: To apply an automated computerised method to categorise and determine the prevalence of different types of lip traits, and to explore associations between lip traits and sex differences. Design: Observational descriptive study utilising an automated method of facial assessment. Setting and participants: A total of 4747 children from...

Objective To determine whether maternal smoking and/or alcohol consumption has an influence on lip morphology. Maternal smoking is a known risk factor for orofacial clefts; however, its influence on normal lip variation is unknown. Recent research regarding normal lip morphology has been contradictory. Design Retrospective cohort study. Setting a...

Collection of occlusal index articles

Currently, the Life Cycle Assessment (LCA) methodology is the most robust evidence-based method to determine environmental impact (EI) of a product or process.•Unlike carbon footprinting, it is a more complete representation of EI, including other areas of concern in addition to GHG emissions, such as natural resource use and effects on ecosystem q...

Introduction: Researchers suggest that within 50 years or less, the available supply of a range of metals will be exhausted, potentially leading to increases in resource conflict and largescale production shortages. The healthcare, dental and orthodontic sectors will undoubtedly be affected as stainless steel instruments are generally heavily relie...

Facial morphology is highly variable, both within and among human populations, and a sizable portion of this variation is attributable to genetics. Previous genome scans have revealed more than 100 genetic loci associated with different aspects of normal-range facial variation. Most of these loci have been detected in Europeans, with few studies fo...

Evidence from model organisms and clinical genetics suggests coordination between the developing brain and face, but the role of this link in common genetic variation remains unknown. We performed a multivariate genome-wide association study of cortical surface morphology in 19,644 individuals of European ancestry, identifying 472 genomic loci infl...

The analysis of contemporary genomic data typically operates on one-dimensional phenotypic measurements (e.g. standing height). Here we report on a data-driven, family-informed strategy to facial phenotyping that searches for biologically relevant traits and reduces multivariate 3D facial shape variability into amendable univariate measurements, wh...

Unaffected relatives of individuals with non-syndromic cleft lip with or without cleft palate (NSCL/P) show distinctive facial features. The presence of this facial endophenotype is potentially an expression of underlying genetic susceptibility to NSCL/P in the larger unselected population. To explore this hypothesis, we first partitioned the face...

Background and Objectives Multilevel statistical models represent the existence of hierarchies or clustering within populations of subjects (or shapes in this work). This is a distinct advantage over single-level methods that do not. Multilevel partial-least squares regression (mPLSR) is used here to study facial shape changes with age during adol...

The human face is complex and multipartite, and characterization of its genetic architecture remains challenging. Using a multivariate genome-wide association study meta-analysis of 8,246 European individuals, we identified 203 genome-wide-significant signals (120 also study-wide significant) associated with normal-range facial variation. Follow-up...

Evidence from both model organisms and clinical genetics suggests close coordination between the developing brain and face, but it remains unknown whether this developmental link extends to genetic variation that drives normal-range diversity of face and brain shape. Here, we performed a multivariate genome-wide association study of cortical surfac...

Purpose The aim of this study was to determine the influence of different morphological lip shape during lip movement. Method A sample of 80 individuals with three-dimensional facial images at rest and during speech were recorded. Subjects were asked to pronounce four bilabial words in a relaxed manner and scanned using the 3dMDFace™ Dynamic Syste...

This cross-sectional study aims to assess the influence of maternal smoking and alcohol consumption during pregnancy on the facial shape of non-syndromic English adolescents and demonstrate the potential benefits of using multilevel principal component analysis (mPCA). A cohort of 3755 non-syndromic 15-year-olds from the Avon Longitudinal Study of...

The human face is complex and multipartite, and characterization of its genetic architecture remains intriguingly challenging. Applying GWAS to multivariate shape phenotypes, we identified 203 genomic regions associated with normal-range facial variation, 117 of which are novel. The associated regions are enriched for both genes relevant to craniof...

Objectives: The aim of this prospective controlled study was to evaluate the effectiveness of the rapid maxillary expander (RME) and facemask treatment by using three-dimensional soft tissue facial characteristics of pre-pubertal Class III children. Setting and sample population: CLIII and non-CLIII groups, both of 32 white children aged 6-8 yea...

Here we study the effects of age on facial shape in adolescents by using a method called multilevel principal components analysis (mPCA). An associated multilevel multivariate probability distribution is derived and expressions for the (conditional) probability of age-group membership are presented. This formalism is explored via Monte Carlo (MC) s...

mPCA Level 1 (ethnicity / sex) level: mode 1 from Finnish (mean - 3SD) to Welsh (mean + 3SD)

mPCA Level 3 (age) level: mode 1 from age 12 (mean - 3SD) to age 17 (mean + 3SD)

mPCA Level 1 (ethnicity / sex) level: mode 2 from Male (mean - 3SD) to Female (mean + 3SD)

mPCA Level 2 (all other "subject" variations) level: mode 1

Background and objectives: The study of age-related facial shape changes across different populations and sexes requires new multivariate tools to disentangle different sources of variations present in 3D facial images. Here we wish to use a multivariate technique called multilevel principal components analysis (mPCA) to study three-dimensional fa...

The human face represents a combined set of highly heritable phenotypes, but knowledge on its genetic architecture remains limited, despite the relevance for various fields. A series of genome-wide association studies on 78 facial shape phenotypes quantified from 3-dimensional facial images of 10,115 Europeans identified 24 genetic loci reaching st...

Introduction: Several studies have highlighted differences in the facial features in a White European population. Genetics appear to have a major influence on normal facial variation, and environmental factors are likely to have minor influences on face shape directly or through epigenetic mechanisms. Aim: The aim of this longitudinal cohort stu...

Classification of facial traits (e.g., lip shape) is an important area of medical research, for example, in determining associations between lip traits and genetic variants which may lead to a cleft lip. In clinical situations, classification of facial traits is usually performed subjectively directly on the individual or recorded later from a thre...

Aim To determine factors that may influence the outcome of orthodontic treatment undertaken in General Dental Services/Personal Dental Services in South East Wales. Design and setting A retrospective study of a requested 20 consecutively treated cases (for the year 2014–2015) provided by 26 performers in South East Wales. Method Performer and pat...

Sean Hamilton's MSc project on lip morphology

The human face represents a combined set of highly heritable phenotypes, but knowledge on its genetic architecture remains limited despite the relevance for various fields of science and application. A series of genome-wide association studies on 78 facial shape phenotypes quantified from 3-dimensional facial images of 10,115 Europeans identified 2...

Background: High levels of prenatal alcohol exposure are known to cause an array of adverse outcomes including fetal alcohol syndrome (FAS); however, the effects of low to moderate exposure are less-well characterized. Previous findings suggest that differences in normal-range facial morphology may be a marker for alcohol exposure and related adve...

Single-level principal component analysis (PCA) and multi-level PCA (mPCA) methods are applied here to a set of (2D frontal) facial images from a group of 80 Finnish subjects (34 male; 46 female) with two different facial expressions (smiling and neutral) per subject. Inspection of eigenvalues gives insight into the importance of different factors...

Introduction: The human face is a complex trait displaying a strong genetic component as illustrated by various studies on facial heritability. Most of these start from sparse descriptions of facial shape using a limited set of landmarks. Subsequently, facial features are preselected as univariate measurements or principal components and the herita...

Single-level Principal Components Analysis (PCA) and multi-level PCA (mPCA) methods are applied here to a set of (2D frontal) facial images from a group of 80 Finnish subjects (34 male; 46 female) with two different facial expressions (smiling and neutral) per subject. Inspection of eigenvalues gives insight into the importance of different factors...

Objectives: Orofacial clefting is one of the most prevalent craniofacial malformations. Previous research has demonstrated that unaffected relatives of patients with non-syndromic cleft lip with/without cleft palate (NSCL/P) show distinctive facial features, which can be an expression of underlying NSCL/P susceptibility genes. These results support...

Non-syndromic cleft lip with or without palate (NSCL/P) is a frequent malformation of the facial region. Genetic variants (SNPs) within nineteen loci have been previously associated with NSCL/P in GWAS studies of European individuals. These common variant SNPs may have subtler effects on the morphology of the lip and face in unaffected individuals....

Many factors influence human facial morphology, including genetics, age, nutrition, biomechanical forces, and endocrine factors. Moreover, facial features clearly differ between males and females, and these differences are driven primarily by the influence of sex hormones during growth and development. Specific genetic variants are known to influen...

Results of the meta-analysis in the post-pubertal subset. Representation of the significant modules of the meta-analysis based on the different discovery datasets.

Results for the 42 candidate SNPs tested for association with five facial ratios in the 3DFN cohort.

List of 44 candidate SNPs selected from the literature.

Complete meta-analysis results for all 32 SNPs tested on the 63 3D facial modules.

Five facial ratios tested for association with the candidate SNPs. (A) Total facial width to height ratio (Total FWH). (B) Upper facial width to height ratio – version 1 (Upper FWH1). (C) Upper facial width to height ratio – version 2 (Upper FWH2). (D) Lower facial width to height ratio (Lower FWH). (E) Upper to lower facial width ratio (Upper:Lowe...

Historically, craniofacial genetic research has understandably focused on identifying the causes of craniofacial anomalies and it has only been within the last 10 years, that there has been a drive to detail the biological basis of normal-range facial variation. This initiative has been facilitated by the availability of low-cost hi-resolution thre...

Multilevel principal components analysis (mPCA) has previously been shown to provide a simple and straightforward method of forming point distribution models that can be used in (active) shape models. Here we extend the mPCA approach to model image texture as well as shape. As a test case, we consider a set of (2D frontal) facial images from a grou...

Evidence-Based Orthodontics, Second Edition retains important elements of the First Edition, with several new sections to improve its use as a quick and comprehensive reference. The first section of the book includes a chapter on the history of evidence-based orthodontics (EBO), as well as updated materials on accessing, assessing, and utilizing th...

Background/objectives: Since a high prevalence of back anomalies has been reported among subjects with crossbite, the aim was to assess the degree of back symmetry among subjects with (crossbite) and without (control) unilateral functional crossbite during the pre-pubertal growth phase. Methods: A group of 70 subjects (36 boys, 34 girls; 6.8 ± 1...

There is increasing evidence that genetic risk variants for non-syndromic cleft lip/palate (nsCL/P) are also associated with normal-range variation in facial morphology. However, previous analyses are mostly limited to candidate SNPs and findings have not been consistently replicated. Here, we used polygenic risk scores (PRS) to test for genetic ov...

Top GWAS hits for nsCL/P compared between published study and our meta-analysis. (DOCX)

Parameters in polygenic risk score analysis power calculations. (DOCX)

nsCL/P Polygenic risk score SNPs. (DOCX)

Power calculations for polygenic risk scoring. (DOCX)

Independent philtrum width trait loci derived from the ALSPAC/3DFN summary statistics. (DOCX)

Biologically plausible facial phenotypes. (DOCX)

Polygenic transmission of nsCL/P genetic risk variants in independent European and Asian trios. (DOCX)

Philtrum width associated SNPs in GTex. (DOCX)

Proxy SNPs (for philtrum width associated variants) in nsCL/P summary statistics. (DOCX)

nsCL/P mendelian randomization SNPs. (DOCX)

The systematic reviews and meta‐analyses tend to focus on a particular anomaly or condition, making a comparison between interventions or controls. This chapter provides a brief overview of genetic and environmental factors that may contribute to the shape of the face, which may have an influence on the outcome of any intervention. Craniofacial gen...

Evidence- Based Orthodontics, Second Edition retains important elements of the First Edition, with several new sections to improve its use as a quick and comprehensive reference. The first section of the book includes a chapter on the history of evidence-based orthodontics (EBO), as well as updated materials on accessing, assessing, and utilizing t...

High levels of prenatal alcohol exposure are known to cause an array of adverse outcomes including foetal alcohol syndrome (FAS); however, the effects of low to moderate exposure are less-well characterised. Previous findings suggest that differences in normal-range facial morphology may be a marker for alcohol exposure and related adverse effects....

Aim: To assess the prevalence of lip traits and to determine the effect that known Single Nucleotide Polymorphisms (SNPs) have on lip morphology in Finnish adults. Method: The published Wilson-Richmond Scale for the classification of lip morphology underwent adaption into a photographic format. Facial photographs of 1,886 individuals from the North...

There is increasing evidence that genetic risk variants for non-syndromic cleft lip/palate (nsCL/P) are also associated with normal-range variation in facial morphology. However, previous analyses are mostly limited to candidate SNPs and findings have not been consistently replicated. Here, we used polygenic risk scores (PRS) to test for genetic ov...

The relationship between the shape and gender of a face, with particular application to automatic gender classification, has been the subject of significant research in recent years. Determining the gender of a face, especially when dealing with unseen examples, presents a major challenge. This is especially true for certain age groups, such as tee...

The human face represents a combined set of highly heritable phenotypes, but knowledge on its genetic architecture remains limited, despite the relevance for various fields. A series of genome-wide association studies on 78 facial shape phenotypes quantified from 3-dimensional facial images of 10,115 Europeans identified 24 genetic loci reaching st...

The Orthodontic waiting lists in Wales are managed and used differently. There needs to be greater consistency in the management of waiting lists and should be monitored annually.

Traditionally, active shape models (ASMs) do not make a distinction between groups in the subject population and they rely on methods such as (single-level) principal components analysis (PCA). Multilevel principal components analysis (mPCA) allows one to model between-group effects and within-group effects explicitly. Three dimensional (3D) laser...

Objectives: To assess arch width, palatal surface area, and volume in surgically treated unilateral cleft lip and palate (UCLP) in mixed dentition children in comparison with non-cleft lip and palate (NCLP) children using a 3D laser scanning. Materials and methods: 38 subjects (Caucasian origin), 5.63-11.9 years of age (mean, 9.33 ? 1.67 years),...

Introduction: Facial phenotype is influenced by genes and environment; however, little is known about their relative contributions to normal facial morphology. The aim of this study was to assess the relative genetic and environmental contributions to facial morphological variation using a three-dimensional (3D) population-based approach and the c...

Background and objective: Methods used in image processing should reflect any multilevel structures inherent in the image dataset or they run the risk of functioning inadequately. We wish to test the feasibility of multilevel principal components analysis (PCA) to build active shape models (ASMs) for cases relevant to medical and dental imaging....

In 2015-16, 9660 patients were accepted for active orthodontic treatment in the GDS/PDS in Wales. This is 136 patients more compared to 2012-13 and 669 more than 2008-09. • There are 26118 unique patient identities in 2015-16 increased by 95 from 2012-13 to 2015-16 and reduced by 8510 compared to 2008-09. • £13,385,493 is spent on orthodontics in 2...

Objective To explore the relationship between the prevalence of sleep disordered breathing (SDB) and face shape morphology in a large cohort of 15-year-old children. Design Observational longitudinal cohort study Setting Avon Longitudinal Study of Parents and Children (ALSPAC), South West of England. Participants Three-dimensional surface laser sca...

Objective: To determine the effect of an audience response system (ARS) on knowledge retention of dental students and to gauge student perceptions of using the ARS. Design: Randomised control study. Setting: School of Dentistry, Cardiff University. Participants: Seventy four second-year dental students were stratified by gender and randomised anony...

A brief overview of 3D activity showing some videos of facial variation, growth and simulation/prediction of orthognathic surgery

Summary The 2011 census and comprehensive data analysis on orthodontic activity in Wales (postcode where the patient resides, re-treatment and some waiting list details) have enabled the best data to be collected on the orthodontic services in Wales to date. Orthodontic treatment provision has increased by 533 and there has been a substantial reduc...