The objective of this study was to determine whether the composite bond strength acquired using a single step self-etching bonding system is as or more effective when compared to the two step etch-rinse-bond system at clinically relevant in-vitro standards. A total of 80 extracted human deciduous with at least one intact smooth surface were collected with parental consent. Collected teeth were randomly assigned to one of four treatment protocols (n=20): single step self-etch (Adper Prompt L-Pop, 3M ESPE), two step etch (15s)-rinse-bond (Optibond Solo Plus, Kerr), single step self etch (Adper L Pop, 3M ESPE) with 30s pre-etch, and two step etch (30s)-rinse-bond (Optibond Solo Plus, Kerr). A composite cylinder of uniform shape was bonded to each tooth using the designated adhesive system and specimens were tested with a universal testing machine. Descriptive statistics and statistical analysis was performed. Median shear bond strengths for all specimens, regardless of treatment group, ranged from 3.25 MPa to 43.13 MPa. These values are above suggested minimum clinical required values of 3MPa. A Kruskal-Wallis analysis between treatment groups found statistical significance (p<0.05) for shear bond strength between the groups and both one step system protocols, had higher mean and median shear bond strength values than the two step systems. An adhesive remnant index (ARI) was analyzed to confirm uniform adhesive fracture between all four treatment groups. Both a Fisher’s exact test, and a Hantel-Haenszel statistic found no significant difference (p<0.05) between the samples. Based on these findings we concluded that: 1. The ARI score for all treatment groups was not statistically significant, suggesting that the type of bond breakage was consistent regardless of adhesive system used. 2. Both Optibond Solo Plus and Adper Prompt L-Pop systems achieve adequate shear bond strengths as described by current literature. 3. The use of a one-step system to save chair time and aid in patient behavior management may be clinically useful.

No description available.

No description available.

No description available.

Temperature changes occur in soils in a number of ways, e. g. landfill liners, around buried services and during sampling. An experimental programme was conducted to examine the effect of temperature (between 10 to 80 °C) on the volume change and shear behaviour of saturated clays. Testing included Liquid Limit (cone penetrometer), residual shear strength (modified Bromhead Ring Shear), laboratory vane shear ( at moisture contents between the Liquid and Plastic Limits) and oedometer tests. An extensive literature survey indicated that kaolinites and smectites would show extremes of thermal behaviour. To examine this two artificially pure clays were tested: English China Clay (a well crystallised kaolinite) and Wyoming Bentonite (a monovalent smectite). To supplement this four British soils were tested: Keuper Marl, Lower Lias Clay, London Clay and Oxford Clay. Full material data were obtained coupled with careful control of stress and thermal histories. It is concluded that two types of extreme thermal response exists: a thermomechanical and a thermo-physicochemical change exhibited by kaolinite and smectite respectively. The temperature sensitivity of clays relative to a particular parameter is positively related to its specific surface area. A quick and repeatable method to qualitatively assess this has been developed: the LUT method. Its advantages include that no temperature calibrations are needed and it has a relatively large operating temperature range, 10 to 80 °C having been successfully used. The consolidation pressure (in the oedometer) needed to change the nature of a soil's thermal response is negatively related to its specific surface area. This, it is postulated, occurs at the same 'critical' contact stress for all clays, i. e. the interparticle threshold stress at which a thermo-physicochemical response changes to a thermo-mechanical one. This threshold stress occurs at a anisotropic consolidation pressure of 60 kPa for a well crystallised kaolinite , at 250 kPa for reconstituted London Clay and at 480 kPa for a mono-valent smectite. Furthermore, greater parallel particle alignment or reconstituting a sample enhances a soil's temperature sensitivity in the oedometer. The thermal changes to consolidation and permeability coefficients can be typically predicted by the corresponding change to the dynamic viscosity of water. Deviations occur with smectites at normal stresses greater than 480 kPa, while for Keuper Marl this occurred at normal stresses of 50 kPa and greater than 850 kPa. Keuper Marl exhibits a greater temperature sensitivity of different parameters than predicted by index tests. This is strongly dependent on consolidation pressure and temperature. At elevated temperatures (>40 °C) and under increasing consolidation pressure, ped units tend to collapse, but once the pressure is removed ped reformation occurs. Thus knowledge of thermal and stress histories, coupled with full material data, is essential to effectively predict temperature effects on the engineering behaviour of soils with any degree of confidence.

The purpose of this research was to investigate the efficacy of a 12 week isokinetic conditioning progam for the lower limbs in 12 young adults with acquired brain injury. There is strong evidence that young adults following ABI (Acquired Brain Injury) have on-going issues with physical impairments and functional limitations many years after their brain injury, and that these limitations are substantial and restrictive. As most therapy resources are available for early rehabilitation only, and these resources are mainly located in large cities, there are many people who are not receiving rehabilitation to support their on-going progress. / There is a paucity of studies investigating conditioning programs in young adults with ABI, and the effect of focusing treatment on the negative rather than the positive features of the Upper Neurone Syndrome (UMNS). The dose prescription for strengthening programs is uncertain, the effect of resistive exercise on tone is controversial and the changes following exercise on muscle strength, muscle power, functional abilities, and quality of life are largely unknown. / The research was in the form of a series of single case studies, with an A-B-A design. For each subject, a series of isokinetic (strength, power, tone) and mobility (gait speed and time to rise from a chair) baseline assessments and 6 subsequent assessments at 2-weekly intervals were performed. The last assessment was performed 4 weeks after cessation of the program to determine any carryover effect. The Short Form-36 questionnaire (SF-36) and semi-structured interviews were administered pre- and post- exercise to reflect the life satisfaction of subjects, and their perspective of any changes in response to the conditioning program. / The multiple isokinetic and mobility measures provided data for analysis of individual cases which were managed statistically, and for clinically significant change. Data was also analysed for the group. Group isokinetic and mobility measures were compared at pre-exercise, post-exercise and 4 weeks following cessation of the conditioning program using repeated measures analysis of variance. / The isokinetic exercise program, on a Kin Com dynamometer, consisted of nine sets of maximal contractions at velocities of 60 and 90 deg/s for unilateral knee flexors and extensors, and ankle plantarflexors and dorsiflexors. These sets were divided into three cycles of six reciprocal contractions. Subjects attended twice weekly for 12 weeks. / The conditioning program resulted in significant improvements in peak torque and power of ankle plantarflexors and peak torque of knee extensors for the group. In addition, functional improvements resulted, in particular fast walking activity, repeated chair rises and participation in activities the subjects valued. There was a carryover effect after the program ceased for some measures. There was no deleterious effect on tone in response to the exercise program. Quality of life of all subjects assessed by using the SF36 questionnaire improved in the area of physical functioning. Occupational status, vitality, self-esteem and optimism were further common themes of improvement obtained from interview data at the completion of the exercise program. / This study demonstrated that a 12 week intensive, resistive, conditioning program produced significant improvement in muscle performance in ankle plantarflexors, knee extensors, function, and participation in valued activities, as well as in feelings of well-being, in a group of ABI subjects. There were no adverse symptoms in response to the high intensity, high repetition exercise protocol at the ankle, indicating that the exercise protocol is suitable for strengthening ankle muscles in individuals following ABI who have a broad range of abilities. / Three subjects experienced knee pain and stiffness in response to the exercise program. These three TBI subjects, who had the highest functional mobility of the group, were able to develop higher torques when exercising, and, the twice weekly, maximal, isokinetic conditioning program might have been excessive for these subjects. The other nine subjects with moderate to severe muscle weakness of knee muscles did not suffer any adverse knee symptoms in response to the conditioning program, and demonstrated improvements in muscle performance of knee muscles. Therefore, when exercising knee muscles, a similar intensive protocol should only be utilized when the individuals have marked or moderate weakness of knee muscles. / These results indicate that a change in therapeutic approach is needed and that the focus for treatment should shift from the positive to the negative features of the UMNS. Rehabilitation of individuals following ABI should incorporate muscle conditioning programs for the lower limbs. Also, many individuals who are currently not receiving therapy may benefit from muscle strengthening exercises. It is important that further research is conducted to establish the most useful conditioning protocol for individuals following ABI. / Thesis (PhDPhysiotherapy)--University of South Australia, 2005.

Thesis (M App Sci) -- University of South Australia, 1992

Thesis (PhD)--University of South Australia, 1996

Thesis (MAppSc in Physiotherapy) -- University of South Australia

Thesis (M App Sc) -- University of South Australia, 1992