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The retentive power of selected dental luting cements has been investigated in-vitro with regard to the effects of taper, temporary cementation and recementation. A standard test method has been developed from measurements of clinically observed tapers and cementation pressures achieved, and account has been taken of the dimensions of human teeth. These observations have indicated a mean clinical taper of 17° to 30° and an initial pressure of 6 kg typically reducing to 3 kg. The order of retention of the various cements has been found to be composites > glass-ionomers/polycarboxylates > zinc phosphate > EBA cement. Prior use of eugeno1-based temporary cements appears to have no adverse effect, except possibly in the case of resin-based composites in conjunction with a volatile cleaning/drying agent. These studies indicate that the effect of taper may be more complex that the literature suggests. In contrast to the accepted view of a monotonic relationship between retention and taper, the current study indicates that for most cements there may in fact be an optimum taper in the range 7° to 15°. The reason for this is unclear. Recementation appears to have no adverse effect on retention. A separate clinical survival study ranked the cements in the order glass-ionomer/polycarboxylate > zinc phosphate > EBA, in full agreement with the in-vitro data.

Nature conservation is a challenging profession. Professionals may face many obstacles before reaching their goals. Conservation work has been described as cognitively challenging, emotionally demanding, and physically straining and, at times, open to dangerous encounters caused by wildlife and people. Furthermore, the field of conservation is ever-changing, both by advances in its or associated disciplines and by rapid changes at a global political, social, and ecological level. Therefore, this doctoral research had as central research question: which role can capacity development have in optimising the work performance of conservation professionals? This study's results, arising from a mixed methods investigation, show that job resources, especially those provided by the organisation, are crucial for professional development and resilience building processes, and for optimising work performance. By thematically analysing the data of 22 interviews and 2 focus groups, organisational resources that were found to be linked to positive psychological states (e.g. experiences of energy, work engagement) were recognition and appreciation, and opportunities for growth and development. Results concerning work resources that were associated with positive psychological states were related to autonomy (i.e. freedom in work) and task significance (i.e. meaningful work). The strengths of these relationships were tested on a dataset obtained through 561 questionnaire respondents and by means of structural equation modelling. Quantitative data results confirmed the central role of job resources in reducing stress and burnout and increasing work engagement, which, in turn, positively influenced work performance. Overall, the results have highlighted the importance of considering both job demands and job resources when optimising work design and work environment for conservationists to maintain energy and perform their jobs well. Furthermore, individual processes of professional learning and resilience building can enhance thriving in the workplace in uncertain and rapidly changing environments.