- Email: [email protected]
Functional morphology of the macropod temporomandibular joint
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Abstracts / HOMO - Journal of Comparative Human Biology 61 (2010) 204–222
period through to the first half of 20th century. Preliminary results suggest a major contrast in levels of registration of births, marriages, and deaths between Maori and Pakeha. These findings depart from previous reports in suggesting differences well into the 20th century. This study also finds relationships between occupational-related deaths and suicides of single men and differences between the two communities in marriage rates, family support and occupation risks. Findings also call into question the extent and accuracy of mortality data officially reported during the 1918 Influenza epidemic. doi:10.1016/j.jchb.2010.01.040 High-dimensional statistical analysis of three-dimensional facial images in the treatment of craniofacial dysmorphologies at PMH M. Walters a , P. Claes b , J. Clement b , P. Sillifant a , D. Gillett a , (a Princess Margaret Hospital for Children, Perth, WA, Australia and b Melbourne Dental School, Victoria, Australia), [email protected] The treatment objectives for reconstructive procedures in children with craniofacial dysmorphologies are to achieve normality. Currently ‘normality’ is defined by a set of averaged facial anthropometric data either based on averaged distances of skeletal landmarks retrieved from plain head films or facial anthropometrics. The advent of high dimensional capture of facial profile with three-dimensional surface scanners, computing power and geometric morphometrics has facilitated a statistical analysis of spatial relationships of faces. In collaboration with the Cranio-Maxillo-Facial Unit at PMH and the Melbourne Dental School we have established the first objective means to generate virtual threedimensional ‘normalised’ facial profiles of patients (a normal equivalent) to be used as a primary surgical objective in cranio-maxillo-facial reconstructive procedures. This has been achieved by ‘mapping’ a patient’s 3D image to a reference range that is referred to as a ‘normative face space’. The patient ‘mapped’ facial manifold is statistically fitted to the normal face space to establish the confidence limits of variation for all vertices (9000 pts). By applying thresholding to these confidence intervals the dysmorphic parts of the face can be isolated and colour coded images/maps generated that assist the treating clinician to define the problem. The use of statistical generated normal equivalent patient images is rapidly being introduced into clinical practice, despite being still in a development phase. doi:10.1016/j.jchb.2010.01.041 Functional morphology of the macropod temporomandibular joint M. Walters a,b , N. Warburton a,c , (a Murdoch University, Western Australia, Australia and b Princess Margaret Hospital for Children, Perth, Western Australia, Australia and c Western Australian Museum, Perth, Australia), [email protected] The temporomandibular joint (TMJ) is a defining feature of the masticatory apparatus of mammals, in which the mandibular condyle articulates with the squamous temporal bone of the skull. Striking differences in TMJ morphology exist between taxa and reflect both phylogeny and the different processing requirements of contrasting diets. The morphological configurations of the articular surfaces reflect varying degrees of mandibular mobility and stability during the masticatory cycle. This paper describes the TMJ anatomy of kangaroos, wallabies and rat kangaroos, as part of a larger study of macropod masticatory apparatus. Macropods are a diverse group of herbivores that can be characterised into distinct feeding groups; grazers, browsers and mixed feeders. Skulls from 22 species of kangaroos were scanned by a laser scanner to retrieve three-dimensional data. TMJ morphology, including articular surfaces, principal axes of rotation and shape were extracted. Considerable variation in TMJ morphology was found. Browsers were characterised by small rounded condyles and a principal axis that is consistent with a predominately hinging action with a limited rotation about the mental symphysis. Grazers, by contrast had condyles with a large surface area with a distinctive concavity that had elliptical
Abstracts / HOMO - Journal of Comparative Human Biology 61 (2010) 204–222
221
expansions on the medial and lateral aspects of the articular surface. This enables rotation of hemimandibles about the symphysis. The vector of the principal axis of the joint reflected this rotational component. The observed variation in macropod TMJ form illustrates the complex interaction between the range of motion and stability required for varied feeding patterns within a single phylogenetic lineage. doi:10.1016/j.jchb.2010.01.042 Hip bone mineral density and geometry in minimally traumatic hip fracture patients M.J. Walters a , J. Meyer b , (a Princess Margaret Hospital for Children, Perth, WA, Australia and b The University of Western Australia, Perth, WA, Australia), [email protected] Minimally traumatic hip fracture is a common occurrence in the elderly and a significant health problem. Means to assess an individual’s fracture risk is important in directing limited resources in order to minimise fracture incidence. Dual-energy X-ray absorptiometry (DXA) estimates of hip bone mineral density (BMD) is the gold standard community screening tool. From these scans projected images of proximal femoral geometry can also be retrieved. This study aims to investigate relationships in proximal femoral geometry, BMD and fracture incidence. In total 133 female fracture cases; 76 cervical (C#), 57 trochanteric (Tr#), had their unfractured limb scanned using DXA within 9 days of fracture. Geometrical measurements of the proximal femur (11 variables) were taken directly from the DXA hardcopy output. Non-fractured controls were obtained from a reference range of 1132 of non-fractured women aged 18–88 years. BMD was found to be age-dependent in fracture patients for all hip sites except for the trochanter. Some geometrical variables were age-dependent, but significant numbers were not. For sub-capital femoral neck widths there was a decrease with increasing age. This contrasted with age-related differences detected in the reference range. Multivariant model using ages, hip BMD and geometrical variables was more effective at discriminating fracture and type from non fractured controls than any other model. The results of this study indicate, that (1) hip geometry is determining fracture type, (2) early detection of fracture risk, particularly cervical fractures, can be achieved with DXA assessment of hip geometry, and (3) multivariant modelling using DXA data to predict hip fracture type may be a more effective diagnostic tool than hip BMD alone. doi:10.1016/j.jchb.2010.01.043 Dental development delays in children with repaired oro-facial clefts M. Walters a , S. Ting a , P. Herbinson b , J. Winters c , (a Princess Margaret Hospital for Children, Subiaco, WA, Australia and b The University of Otago, Dunedin, New Zealand and c Princess Margaret Hospital for Children, Subiaco, WA, Australia), [email protected] Delays in the development of permanent dentition in orofacial cleft patients have been reported. These reports have used either scores of dental emergence of permanent dentition or calcification as seen in panoramic X-rays. This study aims to investigate if a similar pattern of delay occurs in Western Australian children with repaired tooth orofacial clefts. Tooth development was scored from orthopantomograph (OPG) using a revised Gleiser and Hunt dental maturity system with scores ranging from zero–no crypt present to 18–root apex closed. Cleft patients’ OPG (N=340) taken at age 6, 9 and 12 years (±6 months to date of birth) records were collated from the Princess Margaret Hospital CLP Unit’s archive. The control group comprised records of patients without clefts taken from orthodontic practices around Perth. These OPG (N=98) were used at the age 6, 9, 12 years (±6 months to date of birth). A mixed model extension of regression analysis adjusted for age, tooth and sex was carried out to test for differences in tooth development. There was a significant association between cleft patients and delayed tooth development (p<0.0005). Tooth development was delayed by approximately 5 months in children with orofacial cleft defects in comparison to patients without cleft. This delay was consistent by 5 months through out
Abstracts / HOMO - Journal of Comparative Human Biology 61 (2010) 204–222
period through to the first half of 20th century. Preliminary results suggest a major contrast in levels of registration of births, marriages, and deaths between Maori and Pakeha. These findings depart from previous reports in suggesting differences well into the 20th century. This study also finds relationships between occupational-related deaths and suicides of single men and differences between the two communities in marriage rates, family support and occupation risks. Findings also call into question the extent and accuracy of mortality data officially reported during the 1918 Influenza epidemic. doi:10.1016/j.jchb.2010.01.040 High-dimensional statistical analysis of three-dimensional facial images in the treatment of craniofacial dysmorphologies at PMH M. Walters a , P. Claes b , J. Clement b , P. Sillifant a , D. Gillett a , (a Princess Margaret Hospital for Children, Perth, WA, Australia and b Melbourne Dental School, Victoria, Australia), [email protected] The treatment objectives for reconstructive procedures in children with craniofacial dysmorphologies are to achieve normality. Currently ‘normality’ is defined by a set of averaged facial anthropometric data either based on averaged distances of skeletal landmarks retrieved from plain head films or facial anthropometrics. The advent of high dimensional capture of facial profile with three-dimensional surface scanners, computing power and geometric morphometrics has facilitated a statistical analysis of spatial relationships of faces. In collaboration with the Cranio-Maxillo-Facial Unit at PMH and the Melbourne Dental School we have established the first objective means to generate virtual threedimensional ‘normalised’ facial profiles of patients (a normal equivalent) to be used as a primary surgical objective in cranio-maxillo-facial reconstructive procedures. This has been achieved by ‘mapping’ a patient’s 3D image to a reference range that is referred to as a ‘normative face space’. The patient ‘mapped’ facial manifold is statistically fitted to the normal face space to establish the confidence limits of variation for all vertices (9000 pts). By applying thresholding to these confidence intervals the dysmorphic parts of the face can be isolated and colour coded images/maps generated that assist the treating clinician to define the problem. The use of statistical generated normal equivalent patient images is rapidly being introduced into clinical practice, despite being still in a development phase. doi:10.1016/j.jchb.2010.01.041 Functional morphology of the macropod temporomandibular joint M. Walters a,b , N. Warburton a,c , (a Murdoch University, Western Australia, Australia and b Princess Margaret Hospital for Children, Perth, Western Australia, Australia and c Western Australian Museum, Perth, Australia), [email protected] The temporomandibular joint (TMJ) is a defining feature of the masticatory apparatus of mammals, in which the mandibular condyle articulates with the squamous temporal bone of the skull. Striking differences in TMJ morphology exist between taxa and reflect both phylogeny and the different processing requirements of contrasting diets. The morphological configurations of the articular surfaces reflect varying degrees of mandibular mobility and stability during the masticatory cycle. This paper describes the TMJ anatomy of kangaroos, wallabies and rat kangaroos, as part of a larger study of macropod masticatory apparatus. Macropods are a diverse group of herbivores that can be characterised into distinct feeding groups; grazers, browsers and mixed feeders. Skulls from 22 species of kangaroos were scanned by a laser scanner to retrieve three-dimensional data. TMJ morphology, including articular surfaces, principal axes of rotation and shape were extracted. Considerable variation in TMJ morphology was found. Browsers were characterised by small rounded condyles and a principal axis that is consistent with a predominately hinging action with a limited rotation about the mental symphysis. Grazers, by contrast had condyles with a large surface area with a distinctive concavity that had elliptical
Abstracts / HOMO - Journal of Comparative Human Biology 61 (2010) 204–222
221
expansions on the medial and lateral aspects of the articular surface. This enables rotation of hemimandibles about the symphysis. The vector of the principal axis of the joint reflected this rotational component. The observed variation in macropod TMJ form illustrates the complex interaction between the range of motion and stability required for varied feeding patterns within a single phylogenetic lineage. doi:10.1016/j.jchb.2010.01.042 Hip bone mineral density and geometry in minimally traumatic hip fracture patients M.J. Walters a , J. Meyer b , (a Princess Margaret Hospital for Children, Perth, WA, Australia and b The University of Western Australia, Perth, WA, Australia), [email protected] Minimally traumatic hip fracture is a common occurrence in the elderly and a significant health problem. Means to assess an individual’s fracture risk is important in directing limited resources in order to minimise fracture incidence. Dual-energy X-ray absorptiometry (DXA) estimates of hip bone mineral density (BMD) is the gold standard community screening tool. From these scans projected images of proximal femoral geometry can also be retrieved. This study aims to investigate relationships in proximal femoral geometry, BMD and fracture incidence. In total 133 female fracture cases; 76 cervical (C#), 57 trochanteric (Tr#), had their unfractured limb scanned using DXA within 9 days of fracture. Geometrical measurements of the proximal femur (11 variables) were taken directly from the DXA hardcopy output. Non-fractured controls were obtained from a reference range of 1132 of non-fractured women aged 18–88 years. BMD was found to be age-dependent in fracture patients for all hip sites except for the trochanter. Some geometrical variables were age-dependent, but significant numbers were not. For sub-capital femoral neck widths there was a decrease with increasing age. This contrasted with age-related differences detected in the reference range. Multivariant model using ages, hip BMD and geometrical variables was more effective at discriminating fracture and type from non fractured controls than any other model. The results of this study indicate, that (1) hip geometry is determining fracture type, (2) early detection of fracture risk, particularly cervical fractures, can be achieved with DXA assessment of hip geometry, and (3) multivariant modelling using DXA data to predict hip fracture type may be a more effective diagnostic tool than hip BMD alone. doi:10.1016/j.jchb.2010.01.043 Dental development delays in children with repaired oro-facial clefts M. Walters a , S. Ting a , P. Herbinson b , J. Winters c , (a Princess Margaret Hospital for Children, Subiaco, WA, Australia and b The University of Otago, Dunedin, New Zealand and c Princess Margaret Hospital for Children, Subiaco, WA, Australia), [email protected] Delays in the development of permanent dentition in orofacial cleft patients have been reported. These reports have used either scores of dental emergence of permanent dentition or calcification as seen in panoramic X-rays. This study aims to investigate if a similar pattern of delay occurs in Western Australian children with repaired tooth orofacial clefts. Tooth development was scored from orthopantomograph (OPG) using a revised Gleiser and Hunt dental maturity system with scores ranging from zero–no crypt present to 18–root apex closed. Cleft patients’ OPG (N=340) taken at age 6, 9 and 12 years (±6 months to date of birth) records were collated from the Princess Margaret Hospital CLP Unit’s archive. The control group comprised records of patients without clefts taken from orthodontic practices around Perth. These OPG (N=98) were used at the age 6, 9, 12 years (±6 months to date of birth). A mixed model extension of regression analysis adjusted for age, tooth and sex was carried out to test for differences in tooth development. There was a significant association between cleft patients and delayed tooth development (p<0.0005). Tooth development was delayed by approximately 5 months in children with orofacial cleft defects in comparison to patients without cleft. This delay was consistent by 5 months through out