Surface-Sensitive Microwear Texture Analysis of Attrition and Erosion.

Scale-sensitive fractal analysis of high-resolution 3-dimensional surface reconstructions of wear patterns has advanced our knowledge in evolutionary biology, and has opened up opportunities for translatory applications in clinical practice. To elucidate the microwear characteristics of attrition and erosion in worn natural teeth, we scanned 50 extracted human teeth using a confocal profiler at a high optical resolution (X-Y, 0.17 µm; Z < 3 nm). Our hypothesis was that microwear complexity would be greater in erosion and that anisotropy would be greater in attrition. The teeth were divided into 4 groups, including 2 wear types (attrition and erosion) and 2 locations (anterior and posterior teeth; n = 12 for each anterior group, n = 13 for each posterior group) for 2 tissue types (enamel and dentine). The raw 3-dimensional data cloud was subjected to a newly developed rigorous standardization technique to reduce interscanner variability as well as to filter anomalous scanning data. Linear mixed effects (regression) analyses conducted separately for the dependent variables, complexity and anisotropy, showed the following effects of the independent variables: significant interactions between wear type and tissue type ( P = 0.0157 and P = 0.0003, respectively) and significant effects of location ( P < 0.0001 and P = 0.0035, respectively). There were significant associations between complexity and anisotropy when the dependent variable was either complexity ( P = 0.0003) or anisotropy ( P = 0.0014). Our findings of greater complexity in erosion and greater anisotropy in attrition confirm our hypothesis. The greatest geometric means were noted in dentine erosion for complexity and dentine attrition for anisotropy. Dentine also exhibited microwear characteristics that were more consistent with wear types than enamel. Overall, our findings could complement macrowear assessment in dental clinical practice and research and could assist in the early detection and management of pathologic tooth wear.

Features of an effective operative dentistry learning environment: students' perceptions and relationship with performance.

OBJECTIVE: Students' perceptions of their learning environment influence the quality of outcomes they achieve. Learning dental operative techniques in a simulated clinic environment is characterised by reciprocal interactions between skills training, staff- and student-related factors. However, few studies have examined how students perceive their operative learning environments and whether there is a relationship between their perceptions and subsequent performance. Therefore, this study aimed to clarify which learning activities and interactions students perceived as supporting their operative skills learning and to examine relationships with their outcomes. METHODS: Longitudinal data about examples of operative laboratory sessions that were perceived as effective or ineffective for learning were collected twice a semester, using written critical incidents and interviews. Emergent themes from these data were identified using thematic analysis. Associations between perceptions of learning effectiveness and performance were analysed using chi-square tests. RESULTS: Students indicated that an effective learning environment involved interactions with tutors and peers. This included tutors arranging group discussions to clarify processes and outcomes, providing demonstrations and constructive feedback. Feedback focused on mistakes, and not improvement, was reported as being ineffective for learning. However, there was no significant association between students' perceptions of the effectiveness of their learning experiences and subsequent performance. CONCLUSIONS: It was clear that learning in an operative technique setting involved various factors related not only to social interactions and observational aspects of learning but also to cognitive, motivational and affective processes. Consistent with studies that have demonstrated complex interactions between students, their learning environment and outcomes, other factors need investigation.

Dental phenomics: advancing genotype to phenotype correlations in craniofacial research.

The field of dental phenomics provides many opportunities to elucidate the roles of genetic, epigenetic and environmental factors in craniofacial development. To date, research findings have helped to clarify the pathogenesis of many conditions, aiding diagnosis and clinical management. This paper provides an overview of dental phenomics research in some commonly encountered oral diseases in everyday clinical practice, as well as research relating to craniofacial growth and development. Clinically, advances in cariology and periodontology have led to better diagnostic capabilities and treatment provision. In the study of growth and development, important information regarding the varying clinical presentation and pathogenesis of many disorders is now apparent through the accurate quantification of phenotypes. Improvements in two-dimensional (2D) and three-dimensional (3D) imaging and analytical techniques have allowed for accurate dental phenotyping, and efforts are ongoing to apply these in vitro techniques to the in vivo setting. The field of dental phenomics represents an exciting avenue that links research findings to practical application, and collaboration between researcher and clinicians will help advance the field further.

Functional dental occlusion: an anthropological perspective and implications for practice.

Physiologic changes occur in dental occlusion throughout life, resulting from the interplay between functional demands and reciprocating adaptive responses. These changes have been reported in the anthropological literature and they reflect evolutionary changes in the human stomatognathic system during the Paleolithic, hunter-gatherer period. Specific occlusal changes occur in response to different environments, leading to extensive variation within and between extinct and extant human populations. For example, functional demands can cause occlusal and interproximal tooth wear, resulting in shortening of the dental arch, continual tooth eruption and changes in masticatory patterns. Since the advent of farming through to our current industrialized culture, functional demands on the human masticatory system, and its adaptive responses to these demands, have been reduced considerably. Indeed, it is only occasionally that functional demands are severe enough to lead to obvious pathology in the modern human dentition. In contrast to normal masticatory activity, 'modern-day conditions' such as dental caries, periodontal disease and erosion, can lead to significant changes in dental occlusion that are pathological and need to be treated. The masticatory system is a dynamic, functional unit that displays considerable change over a lifetime. In this concept paper, it is proposed that modern human populations living in industrialized environments display dental occlusions that can be considered to be 'neotenous'; that is, our dentitions tend to reflect an unworn stage of our ancestors that was only seen in infants, juveniles and young adults. Clinicians can draw on both phylogenetic and ontogenetic perspectives of 'functional dental occlusion' to differentiate continual physiological changes occurring over time that require ongoing review, from pathological responses that require intervention.

The teeth and faces of twins: providing insights into dentofacial development and oral health for practising oral health professionals.

The continuing studies of the teeth and faces of Australian twins and their families in the Craniofacial Biology Research Group in the School of Dentistry at the University of Adelaide began 30 years ago. Three main cohorts of twins have been recruited, enabling various objectives and specific hypotheses to be addressed about the roles of genetic, epigenetic and environmental influences on human dentofacial growth and development, as well as oral health. This paper highlights some key findings arising from these studies, emphasizing those of direct relevance to practising oral health professionals. We also draw on published literature to review the significant developments in relation to the use of precision 2D and 3D imaging equipment, the application of modern molecular techniques, and the development of sophisticated computer software for analysing genetic relationships and comparing complex shapes. Such developments are valuable for current and future work. Apart from the classical or traditional twin model, there are several other twin models that can be used in research to clarify the relative contributions of genetic, epigenetic and environmental contributions to phenotypic variation. The monozygotic (MZ) co-twin model is one particularly valuable method, given that examination of only one pair of MZ twins can provide considerable insights into underlying causes of observed variation. This model can be used in a dental practice environment, with oral health professionals having the opportunity to explore differences in orofacial structures between MZ co-twins who are attending as patients. As researchers have become more aware of the complexities of the interactions between the genome, the epigenome and the environment during development, there is the need to collect more phenotypic data and define new phenotypes that will better characterize variations in growth processes and health status. When coupled with powerful new genetic approaches, including genome-wide association studies and linkage analyses, exciting opportunities are opening up to unravel the causes of problems in craniofacial growth and common oral diseases in human populations.

Reorientating dental curricula to reflect a minimally invasive dentistry approach for patient-centred management.

Minimally invasive dentistry (MID), together with patient-centred care (PCC), can be considered central to patient management. These approaches have been incorporated in the structure of various dental curricula and indeed formally assessed. However, there is limited evidence that students have an integrated skill-set and are able to apply these skills when providing direct patient care within the clinical setting. Assessment of students' application of core clinical skills has identified numerous deficiencies that need to be addressed. The revised Bachelor of Dental Surgery curriculum at the School of Dentistry, The University of Adelaide, provides an example of how MID, underpinned by PCC, can be presented throughout a dental curriculum. Essentially, MID and PCC are not considered as separate subjects but as a patient management approach that is 'woven into the whole fabric' of the curriculum. The programme relies on the development of empathic communication skills that enable students to obtain key patient information, including their patients' values, beliefs, needs, preferences and expectations, thereby allowing management to be tailor-made. As a result, patients are empowered to be a part of the oral health care team. The Adelaide undergraduate dental curriculum consists of one clinical stream called Dental Science and Practice (DSP), that promotes the application of student knowledge, skills and behaviours in the clinical setting. Vertical and horizontal integration, aligned with an integrated approach to assessment, drives the learning throughout the programme. Clearly-defined outcomes are introduced by Integrated Learning Activities (ILAs) that provide a focus for associated learning activities (e.g. class meetings, tutorials, simulation laboratories, etc). The aim of this approach to learning and teaching is to ensure the required learning outcomes are achieved. It also requires coordinated teaching teams including trained external tutors who clearly understand all aspects of MID and PCC within the curriculum structure.

Acquiring psychomotor skills in operative dentistry: do innate ability and motivation matter?

OBJECTIVE: The acquisition of psychomotor skills is a key competence in the practice of dentistry, and innate abilities and motivation have been shown to influence motor performance. However, the explicit integration of these factors into the design of research projects about skill acquisition in dentistry has been limited. Therefore, the purpose of this study was to provide a comprehensive analysis of how dental students' abilities and motivation affected their performance in an operative task. METHODS: A longitudinal study with two cohorts of dental students was conducted in laboratory classes forming part of an operative technique course. A range of standardised psychometric tests was used to assess different abilities before completing a cavity preparation on Frasaco teeth. This was followed immediately by completion of an Intrinsic Motivation Inventory. RESULTS: Low but statistically significant correlations (P<0.05) were found between dental performance and psychomotor ability (r=0.22), and also dental performance and motivation (r=0.19). A significant difference (P<0.05) was found in the grades obtained for the cavity preparation exercise in one cohort between students with higher levels of psychomotor ability compared with those with lower levels (Tracing scores) (P<0.05). No significant differences in grades obtained for the cavity preparation exercise were found between students with higher and lower levels of motivation. CONCLUSION: Both innate psychomotor ability and motivation showed only weak positive associations with dental performance on cavity preparation exercises. Our study suggests that student-related factors only provide limited information to explain differences in performance or to be useful as specific predictors of future performance by individuals.

Improving clinical assessment: evaluating students' ability to identify and apply clinical criteria.

AIM: There is ongoing concern by health educators over the inability of professionals to accurately self-assess their clinical behaviour and standards, resulting in doubts over a key expectation of effective self-regulation in the health professions. Participation by students in the assessment process has been shown to increase the understanding of assessment criteria in written assessment tasks. How this might transfer to the clinical setting is the focus of this study. This paper is part of an ongoing investigation of the impact on learning of a series of activities that provides students with opportunities to discuss and apply criteria and standards associated with self-assessment in clinical dentistry. Our aim was to evaluate whether participation in these assessment activities improved the ability of first-year dental students to recognise behaviours demonstrated by 'peers' in videos of clinical scenarios and to relate these to the assessment criteria. MATERIALS AND METHODS: A series of three workshops in conjunction with weekly clinical assessment activities in Semesters 1 and 2 were use to support first-year students' learning of clinical assessment criteria. The design of the workshops was based on the principles of social constructivist theories of learning and the concept of tacit knowledge. Accordingly workshop activities were planned around videos that were specifically constructed to illustrate procedures and behaviours typical of those observed by staff and tutors in the first year of the dental course at The University of Adelaide, Australia. First-year students viewed the videos prior to and after the workshops and recorded observed behaviours that related to the assessment criteria that were used in their clinical practice course. Student learning outcomes were assessed 10-14 weeks after the initial workshop and again up to 42 weeks later. To check whether learning resulted from repeated viewing of the videos without formal discussion, a reference group of third-year students who did not attend the workshops also viewed the videos two times, separated by 12 weeks, and recorded observations in the same way. RESULTS: There was no consistent evidence that repeat viewing of the videos in isolation resulted in improved recognition of 'peer' behaviours by third-year dental students. Results for the first-year students indicated that the workshops and clinical assessment activities had a significantly positive effect on the ability of students to identify 'peer' behaviours related to the criteria used for clinical assessment. In particular, students' recognition in others of knowledge and professional behaviours improved significantly. This improvement was retained over the year and students were able to recognise these behaviours in other scenarios relevant to their year level. CONCLUSIONS: This early exposure to the process of clinical assessment, coupled with ongoing self-assessment and tutor feedback throughout first year, improved the ability of first-year students to identify and apply some key assessment criteria to observed 'peer' behaviour, and this ability was retained over time.

Evidence-based care and the curriculum.

An evidence-based (EB) approach has been a significant driver in reforming healthcare over the past two decades. This change has extended across a broad range of health professions, including oral healthcare. A key element in achieving an EB approach to oral healthcare is educating our practitioners, both current and future. This involves providing opportunities integrated within simulated and actual clinical settings for practitioners to learn and apply the principles and processes of evidence-based oral healthcare (EBOHC). Therefore, the focus of this discussion will be on ways in which EBOHC and associated research activities can be implemented into curricula, with the aim of improving patient care. This paper will initially define the scope of EBOHC and research, what these involve, why they are important, and issues that we need to manage when implementing EBOHC. This will be followed by a discussion of factors that enable successful implementation of EBOHC and research into curricula. The paper concludes with suggestions on the future of EBOHC and research in curricula. Key recommendations related to curricula include strengthening of the culture of a scientific approach to education and oral healthcare provision; complete integration of EBOHC into the curriculum at all levels; and faculty development to implement EBOHC based on their needs and evidence of effective approaches. Key recommendations to support implementation and maintenance of EBOHC include recognition and funding for high-quality systematic reviews and development of associated methodologies relevant for global environments; building global capacity of EBOHC researchers; research into improving translation of effective interventions into education and healthcare practice, including patient-reported outcomes, safety and harms, understanding and incorporation of patient values into EB decision-making, economic evaluation research specific to oral healthcare and effective methods for changing practitioner (faculty) behaviours; and extend access to synthesized research in 'user friendly' formats and languages tailored to meet users' needs. Realizing these recommendations may help to improve access to effective healthcare as a basic human right.

Studies on dental erosion: An in vivo-in vitro model of endogenous dental erosion--its application to testing protection by fluoride gel application.

BACKGROUND: The objective in this study was to develop an in vivo-in vitro model of endogenous erosion, with a view to exploring the potential for some degree of its control by the use of topical fluoride gel application to teeth. METHODS: Six volunteers each wore a small clasp retained palatal acrylic appliance to which six sterilized enamel tiles were bonded. Three tiles on each appliance were coated extra-orally with either 1.23 per cent acidulated phosphate fluoride (APF) or 2.2 per cent sodium fluoride (NaF) neutral gel for four minutes prior to multiple periods of exposure to the simulated gastric acid, cumulating in 16, 36, 80 and 150 minutes of exposure. Impressions of the enamel tiles prior to and following acid exposure permitted dies to be prepared. These were sectioned through the exposed areas and examined under a stereomicroscope to assess maximum depths of erosion. RESULTS: The depth of erosive demineralization of enamel was found to be greatly reduced with increased frequency of APF gel application. The reduction in enamel loss was less following topical application of NaF gel. CONCLUSIONS: It was concluded that fluoride gels significantly reduced enamel erosion using this in vivo-in vitro model and therefore, if prescribed appropriately, should help reduce tooth tissue loss from endogenous erosion.

Limb salvage surgery in primary bone tumors. The Saint Savvas experience in 52 patients.

Between 1983 and 1996, 52 patients with primary bone neoplasms underwent limb salvage surgery using endoprostheses in 36 cases, internal hemipelvectomy in 6 cases, Tihoff-Lindberg arthroplasty in 9, and knee arthrodeses in 2 patients. 22 of 36 patients with an endoprostheses could walk without instability or pain. However, major complications occurred as local recurrence in 9 patients and deep infection in 5 patients which led to amputation in 2 patients. Good function was achieved in all patients that underwent hemipelvectomy, but the local recurrence rate was high. Good function was also achieved in patients who underwent a Tihoff-Lindberg procedure.