Grant Townsend
Biographic Data
| ID | 3808548 |
|---|---|
| NAME | Grant Townsend |
| GIVEN NAMES | Grant |
| FAMILY NAME | Townsend |
| SIGNATURE | TOWNSEND G |
| AFFILIATIONS | Adelaide Dental School University of Adelaide Adelaide South Australia 5005 Australia |
| VERIFIED | No |
| TOTAL WORKS | 23 |
| TOTAL CITATIONS | 30 |
| AUTHOR COUNT | 23 |
| EDITOR COUNT | 0 |
| FIRST PUBLICATION YEAR | 1984 |
| LATEST PUBLICATION YEAR | 2020 |
| H-INDEX | 3 |
The functional role of the Carabelli trait in early and late hominins
The Carabelli trait is a dental feature that forms along the lingual margin of the protocone of deciduous and permanent maxillary molars. It is variably expressed, ranging from a small pit or furrow to a large cusp, and its development seems to be associated with crown size and molar cusp spatial configuration. The degree of expression of the Carabelli trait differs systematically between hominin taxa, and for this reason, it has been used extens…
The physiological linkage between molar inclination and dental macrowear pattern
OBJECTIVES: Exact symmetry and perfect balance between opposite jaw halves, as well as between antagonistic teeth, is not frequently observed in natural masticatory systems. Research results show that asymmetry in our body, skull, and jaws is often related to genetic, epigenetic, environmental and individual ontogenetic factors. Our study aims to provide evidence for a significant link between masticatory asymmetry and occlusal contact between an…
Three‐dimensional (3D) geometric morphometric analysis of human premolars to assess sexual dimorphism and biological ancestry in Australian populations
OBJECTIVES: This study aimed to investigate size and shape variation of human premolars between Indigenous Australians and Australians of European ancestry, and to assess whether sex and ancestry could be differentiated between these groups using 3D geometric morphometrics. MATERIALS AND METHODS: Seventy dental casts from each group, equally subdivided by sex, were scanned using a structured-light scanner. The 3D meshes of upper and lower premola…
Intra- and Inter-population Variability in Mamelon Expression on Incisor Teeth
Although rounded protubernaces referred to as mamelons are observes commonly on the crowns of newly-emerged human incisor teeth, there have been very few systematic studies of their expression. The main aims of this study were to describe the nature and extent of variation of mamelon expression on permanent incisors within and between two different human populations, and to quantify the contributions of genetic and environmental influences to obs…
In Memoriam
Localized Asymmetry in Human Dental Crown Form—an Interesting Case
A case of a 20-year-old female is described in which the premolars and molars on the right side of the arch display altered crown proportions and altered occlusal morphology. There is no evidence of an orofacial congenital disorder or history of trauma. It is argued that the asymmetrical expression of crown form does not fall within the normal range of variation but has resulted from a localized disruption in cellular function within the developi…
Form, Symmetry and Asymmetry of the Dental Arch
There have been numerous attempts to quantify the shape of the dental arch mathematically, with orthogonal polynomial curves providing a robust and versatile method for quantifying variation in both shape and asymmetry. Lu (1966) first presented the theoretical basis for fitting orthogonal polynomials to arch shape data. Whilst theoretically sound, Lu’s original paper contained several arithmetic errors and a number of incorrect assumptions. In t…
Mirror Imaging in Twins
Carabelli Trait in Australian Twins
We assessed the intra- and inter-observer reliability of two methods of scoring or categorizing Carabelli trait in both primary and permanent dentitions (Hanihara, 1961; Dahlberg, 1963). By using dental casts obtained from twins, we also compared the expression of Carabelli trait within and between monozygotic (MZ) co-twins to clarify the ontogenetic processes leading to different forms of trait expression. While intra-observer concordance rates …
Cervical Enamel Projections and Enamel Pearls in a Collection of Australian Extracted Molars
Cervical enamel pearls (CEPs) and enamel pearls (EPs) are generally located on permanent molars. They are detected less frequently in Caucasian than in Mongoloid teeth. No data are available documenting these features in teeth collected in Australia. The aim of this study was to determine the frequency and degree of expression of CEPs and EPs in a large sample of Caucasian deciduous and permanent extracted dried molars. The molars were scored for…
Corono-Radicular Grooves in a Large Sample of Human Maxillary Incisors
Corono-radicular grooves (CRGs) are developmental anomalies on maxillary incisor teeth that have both anthropological and clinical significance. Their reported prevalence varies from around 2% in modern Caucasoid populations to 18% in Chinese, although methods of classification have differed between studies. The aim of this study was to determine the frequency of occureence and configuration of these grooves in a large sample of Caucasoid extract…
Frequency of Occurrence and Degree of Expression of the Parastyle in Several Modern Human Populations
The aims of this study are to describe the frequency of occurrence and degree of expression of the parastyle in six different ethnic groups; to assess inter- and intra-observer errors when scoring the feature; and to compare the expression of the feature in a small number of twin pairs. Dental casts were examined for evidence of the parastyle from samples available in the Adelaide Dental School. A dental plaque developed by Katich & Turner was us…
Neanderthal behaviour, diet, and disease inferred from ancient DNA in dental calculus
Sequencing ancient calcified dental plaque shows changes in oral microbiota with dietary shifts of the Neolithic and Industrial revolutions
Prevalence and patterning of maxillary premolar accessory ridges (MxPARs) in several human populations
We present new data on the prevalence and patterning of the maxillary premolar accessory ridge (MxPAR), a common but understudied morphological dental trait that is expressed as a linear elevation extending from the buccal cusp ridge to the medial sulcus of maxillary premolar teeth. A total of 579 sets of dental casts, representing six ethnic groups, were scored using the five‐grade system proposed by Burnett et al. (2010). The frequency and dist…
Tooth use in Aboriginal Australia
The study of dental casts taken from living people avoids the ethical problems of research into human remains, while providing valuable information about diet and life styles. This article describes a study of tooth wear in dental casts of three different groups of Australian Aborigines. The authors describe their methods of recording and report differential patterns of wear in the different groups. Preliminary interpretation relates the wear pat…
Gaining New Insights into How Genetic Factors Influence Human Dental Development by Studying Twins
Many previous attempts to quantify the contribution of genetic factors to human dental variation using the classical twin design have been based on untested assumptions that lead to unreliable estimates of heritability. We have applied structural equation modelling to several different dental phenotypes in a sample of over 600 pairs of Australian twins, enabling the goodness-of-fit of the data to be tested against genetic models incorporating dif…
Student experiences of assessment in two problem‐based dental curricula
Dental students in third (n = 35) and fifth years (n = 50) at Adelaide and Trinity College Dental Schools were surveyed about their experiences of assessment and their perceptions of the importance of particular aspects of assessment. Students reported on their assessment experience within their programmes by describing a critical assessment incident and their response to it, and also rated assessment purposes and features using a 5‐point Likert …
Effect of Down syndrome on the dimensions of dental crowns and tissues
Effect of Down syndrome on the dimensions of dental crowns and tissues
Abnormal growth in Down syndrome (DS) is reflected by variable reduction in size and simplification in form of many physical traits. This study aimed to compare the thickness of enamel and dentine in deciduous and permanent mandibular incisor teeth between DS and non-DS individuals and to clarify how these tissues contribute to altered tooth size in DS. Sample groups comprised 61 mandibular incisors (29 permanent and 32 deciduous) from DS individ…
Crown size variability in the deciduous dentition of South Australian children
Although many studies of the permanent dentition have been published, there are still relatively few reports relating to variability within the deciduous dentition. The aim of this study was to provide a detailed description of crown size variability in the deciduous dentition of South Australian children. Dental impressions were obtained of 160 children, 3-6 years of age, and stone models constructed. Mesiodistal and buccolingual crown diameters…
Expression of the entoconulid (sixth cusp) on mandibular molar teeth of an Australian aboriginal population
The expression and genetic basis of the entoconulid (sixth cusp) on mandibular molars were examined in a geographically isolated group of aboriginals from Yuendumu in the Northern Territory of Australia. Four grades of trait expression, ranging from trace to small, medium, and large cusps, were defined on dental casts of 399 subjects. Frequencies of occurrence were among the highest reported in human populations. Approximately 80% of dm2s showed …
Reduced tooth size in 45,X (Turner syndrome) females
Mean values and variances of deciduous and permanent tooth dimensions were compared between 121 45,X (Turner syndrome) females and 171 control subjects to clarify the role of the X chromosome on dental development. Although deciduous molars tended to be smaller than normal in 45,X females, there was no evidence of a reduction in tooth size for deciduous anterior teeth. In the permanent dentition, all mesiodistal dimensions were significantly smal…
Expression of the entoconulid (sixth cusp) on mandibular molar teeth of an Australian aboriginal population
The expression and genetic basis of the entoconulid (sixth cusp) on mandibular molars were examined in a geographically isolated group of aboriginals from Yuendumu in the Northern Territory of Australia. Four grades of trait expression, ranging from trace to small, medium, and large cusps, were defined on dental casts of 399 subjects. Frequencies of occurrence were among the highest reported in human populations. Approximately 80% of dm2s showed …
The physiological linkage between molar inclination and dental macrowear pattern
OBJECTIVES: Exact symmetry and perfect balance between opposite jaw halves, as well as between antagonistic teeth, is not frequently observed in natural masticatory systems. Research results show that asymmetry in our body, skull, and jaws is often related to genetic, epigenetic, environmental and individual ontogenetic factors. Our study aims to provide evidence for a significant link between masticatory asymmetry and occlusal contact between an…
Three‐dimensional (3D) geometric morphometric analysis of human premolars to assess sexual dimorphism and biological ancestry in Australian populations
OBJECTIVES: This study aimed to investigate size and shape variation of human premolars between Indigenous Australians and Australians of European ancestry, and to assess whether sex and ancestry could be differentiated between these groups using 3D geometric morphometrics. MATERIALS AND METHODS: Seventy dental casts from each group, equally subdivided by sex, were scanned using a structured-light scanner. The 3D meshes of upper and lower premola…
Localized Asymmetry in Human Dental Crown Form—an Interesting Case
A case of a 20-year-old female is described in which the premolars and molars on the right side of the arch display altered crown proportions and altered occlusal morphology. There is no evidence of an orofacial congenital disorder or history of trauma. It is argued that the asymmetrical expression of crown form does not fall within the normal range of variation but has resulted from a localized disruption in cellular function within the developi…
Gaining New Insights into How Genetic Factors Influence Human Dental Development by Studying Twins
Many previous attempts to quantify the contribution of genetic factors to human dental variation using the classical twin design have been based on untested assumptions that lead to unreliable estimates of heritability. We have applied structural equation modelling to several different dental phenotypes in a sample of over 600 pairs of Australian twins, enabling the goodness-of-fit of the data to be tested against genetic models incorporating dif…
Reduced tooth size in 45,X (Turner syndrome) females
Mean values and variances of deciduous and permanent tooth dimensions were compared between 121 45,X (Turner syndrome) females and 171 control subjects to clarify the role of the X chromosome on dental development. Although deciduous molars tended to be smaller than normal in 45,X females, there was no evidence of a reduction in tooth size for deciduous anterior teeth. In the permanent dentition, all mesiodistal dimensions were significantly smal…
Carabelli Trait in Australian Twins
We assessed the intra- and inter-observer reliability of two methods of scoring or categorizing Carabelli trait in both primary and permanent dentitions (Hanihara, 1961; Dahlberg, 1963). By using dental casts obtained from twins, we also compared the expression of Carabelli trait within and between monozygotic (MZ) co-twins to clarify the ontogenetic processes leading to different forms of trait expression. While intra-observer concordance rates …
The functional role of the Carabelli trait in early and late hominins
The Carabelli trait is a dental feature that forms along the lingual margin of the protocone of deciduous and permanent maxillary molars. It is variably expressed, ranging from a small pit or furrow to a large cusp, and its development seems to be associated with crown size and molar cusp spatial configuration. The degree of expression of the Carabelli trait differs systematically between hominin taxa, and for this reason, it has been used extens…
Reduced tooth size in 45,X (Turner syndrome) females
Mean values and variances of deciduous and permanent tooth dimensions were compared between 121 45,X (Turner syndrome) females and 171 control subjects to clarify the role of the X chromosome on dental development. Although deciduous molars tended to be smaller than normal in 45,X females, there was no evidence of a reduction in tooth size for deciduous anterior teeth. In the permanent dentition, all mesiodistal dimensions were significantly smal…
Expression of the entoconulid (sixth cusp) on mandibular molar teeth of an Australian aboriginal population
The expression and genetic basis of the entoconulid (sixth cusp) on mandibular molars were examined in a geographically isolated group of aboriginals from Yuendumu in the Northern Territory of Australia. Four grades of trait expression, ranging from trace to small, medium, and large cusps, were defined on dental casts of 399 subjects. Frequencies of occurrence were among the highest reported in human populations. Approximately 80% of dm2s showed …
Crown size variability in the deciduous dentition of South Australian children
Although many studies of the permanent dentition have been published, there are still relatively few reports relating to variability within the deciduous dentition. The aim of this study was to provide a detailed description of crown size variability in the deciduous dentition of South Australian children. Dental impressions were obtained of 160 children, 3-6 years of age, and stone models constructed. Mesiodistal and buccolingual crown diameters…
Effect of Down syndrome on the dimensions of dental crowns and tissues
Effect of Down syndrome on the dimensions of dental crowns and tissues
Abnormal growth in Down syndrome (DS) is reflected by variable reduction in size and simplification in form of many physical traits. This study aimed to compare the thickness of enamel and dentine in deciduous and permanent mandibular incisor teeth between DS and non-DS individuals and to clarify how these tissues contribute to altered tooth size in DS. Sample groups comprised 61 mandibular incisors (29 permanent and 32 deciduous) from DS individ…
Student experiences of assessment in two problem‐based dental curricula
Dental students in third (n = 35) and fifth years (n = 50) at Adelaide and Trinity College Dental Schools were surveyed about their experiences of assessment and their perceptions of the importance of particular aspects of assessment. Students reported on their assessment experience within their programmes by describing a critical assessment incident and their response to it, and also rated assessment purposes and features using a 5‐point Likert …
Gaining New Insights into How Genetic Factors Influence Human Dental Development by Studying Twins
Many previous attempts to quantify the contribution of genetic factors to human dental variation using the classical twin design have been based on untested assumptions that lead to unreliable estimates of heritability. We have applied structural equation modelling to several different dental phenotypes in a sample of over 600 pairs of Australian twins, enabling the goodness-of-fit of the data to be tested against genetic models incorporating dif…
Tooth use in Aboriginal Australia
The study of dental casts taken from living people avoids the ethical problems of research into human remains, while providing valuable information about diet and life styles. This article describes a study of tooth wear in dental casts of three different groups of Australian Aborigines. The authors describe their methods of recording and report differential patterns of wear in the different groups. Preliminary interpretation relates the wear pat…
Sequencing ancient calcified dental plaque shows changes in oral microbiota with dietary shifts of the Neolithic and Industrial revolutions
Prevalence and patterning of maxillary premolar accessory ridges (MxPARs) in several human populations
We present new data on the prevalence and patterning of the maxillary premolar accessory ridge (MxPAR), a common but understudied morphological dental trait that is expressed as a linear elevation extending from the buccal cusp ridge to the medial sulcus of maxillary premolar teeth. A total of 579 sets of dental casts, representing six ethnic groups, were scored using the five‐grade system proposed by Burnett et al. (2010). The frequency and dist…
Neanderthal behaviour, diet, and disease inferred from ancient DNA in dental calculus
The physiological linkage between molar inclination and dental macrowear pattern
OBJECTIVES: Exact symmetry and perfect balance between opposite jaw halves, as well as between antagonistic teeth, is not frequently observed in natural masticatory systems. Research results show that asymmetry in our body, skull, and jaws is often related to genetic, epigenetic, environmental and individual ontogenetic factors. Our study aims to provide evidence for a significant link between masticatory asymmetry and occlusal contact between an…
Three‐dimensional (3D) geometric morphometric analysis of human premolars to assess sexual dimorphism and biological ancestry in Australian populations
OBJECTIVES: This study aimed to investigate size and shape variation of human premolars between Indigenous Australians and Australians of European ancestry, and to assess whether sex and ancestry could be differentiated between these groups using 3D geometric morphometrics. MATERIALS AND METHODS: Seventy dental casts from each group, equally subdivided by sex, were scanned using a structured-light scanner. The 3D meshes of upper and lower premola…
Intra- and Inter-population Variability in Mamelon Expression on Incisor Teeth
Although rounded protubernaces referred to as mamelons are observes commonly on the crowns of newly-emerged human incisor teeth, there have been very few systematic studies of their expression. The main aims of this study were to describe the nature and extent of variation of mamelon expression on permanent incisors within and between two different human populations, and to quantify the contributions of genetic and environmental influences to obs…
In Memoriam
Localized Asymmetry in Human Dental Crown Form—an Interesting Case
A case of a 20-year-old female is described in which the premolars and molars on the right side of the arch display altered crown proportions and altered occlusal morphology. There is no evidence of an orofacial congenital disorder or history of trauma. It is argued that the asymmetrical expression of crown form does not fall within the normal range of variation but has resulted from a localized disruption in cellular function within the developi…
Form, Symmetry and Asymmetry of the Dental Arch
There have been numerous attempts to quantify the shape of the dental arch mathematically, with orthogonal polynomial curves providing a robust and versatile method for quantifying variation in both shape and asymmetry. Lu (1966) first presented the theoretical basis for fitting orthogonal polynomials to arch shape data. Whilst theoretically sound, Lu’s original paper contained several arithmetic errors and a number of incorrect assumptions. In t…
Mirror Imaging in Twins
Carabelli Trait in Australian Twins
We assessed the intra- and inter-observer reliability of two methods of scoring or categorizing Carabelli trait in both primary and permanent dentitions (Hanihara, 1961; Dahlberg, 1963). By using dental casts obtained from twins, we also compared the expression of Carabelli trait within and between monozygotic (MZ) co-twins to clarify the ontogenetic processes leading to different forms of trait expression. While intra-observer concordance rates …
Cervical Enamel Projections and Enamel Pearls in a Collection of Australian Extracted Molars
Cervical enamel pearls (CEPs) and enamel pearls (EPs) are generally located on permanent molars. They are detected less frequently in Caucasian than in Mongoloid teeth. No data are available documenting these features in teeth collected in Australia. The aim of this study was to determine the frequency and degree of expression of CEPs and EPs in a large sample of Caucasian deciduous and permanent extracted dried molars. The molars were scored for…
Corono-Radicular Grooves in a Large Sample of Human Maxillary Incisors
Corono-radicular grooves (CRGs) are developmental anomalies on maxillary incisor teeth that have both anthropological and clinical significance. Their reported prevalence varies from around 2% in modern Caucasoid populations to 18% in Chinese, although methods of classification have differed between studies. The aim of this study was to determine the frequency of occureence and configuration of these grooves in a large sample of Caucasoid extract…
Frequency of Occurrence and Degree of Expression of the Parastyle in Several Modern Human Populations
The aims of this study are to describe the frequency of occurrence and degree of expression of the parastyle in six different ethnic groups; to assess inter- and intra-observer errors when scoring the feature; and to compare the expression of the feature in a small number of twin pairs. Dental casts were examined for evidence of the parastyle from samples available in the Adelaide Dental School. A dental plaque developed by Katich & Turner was us…
The functional role of the Carabelli trait in early and late hominins
The Carabelli trait is a dental feature that forms along the lingual margin of the protocone of deciduous and permanent maxillary molars. It is variably expressed, ranging from a small pit or furrow to a large cusp, and its development seems to be associated with crown size and molar cusp spatial configuration. The degree of expression of the Carabelli trait differs systematically between hominin taxa, and for this reason, it has been used extens…
Medicine (19 works) · Dentistry (16 works) · Biology (15 works) · Orthodontics (14 works) · dental development and anomalies (12 works) · Molar (11 works) · Forensic Anthropology and Bioarchaeology Studies (7 works) · Enamel paint (5 works) · Mathematics (5 works) · Orthodontics (5 works)