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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The influence of compressive cyclic loading on the retention of cast crown copings cemented to implant abutments.

Dudley, James January 2008 (has links)
Summary Background The cementation of crowns to dental implant abutments is an accepted form of crown retention that requires consideration of the properties of available cements within the applied clinical context. Most current dental cements were developed primarily for use with natural tooth crowns, but must act in a different manner with implant components. Cements are exposed to a number of stressors that may reduce crown retention in vivo, not the least of which is occlusal loading. This study investigated the influence of compressive cyclic loading on the physical retention of cast crown copings cemented to implant abutments. Method Cast crown copings were cemented to Straumann synOcta titanium implant abutments with three different readily used and available cements. Specimens were placed in a humidifier, thermocycled and subjected to one of four quantities of compressive cyclic loading. The uniaxial tensile force required to remove the cast crown copings was then recorded. Data analysis was conducted using two-way ANOVA and paired post tests. Results Statistical analysis arising from post tests following two-way ANOVA testing revealed the mean retention values for crown copings cemented with Panavia-F cement (5.103, 2.681, 3.178, 2.986MPa) were statistically significantly greater than both KetacCem (0.646, 0.701, 1.083, 0.914MPa) and TempBond non–eugenol (0.074, 0.181, 0.190, 0.303MPa) cements at each compressive cyclic loading quantity. KetacCem and TempBond non–eugenol cements produced relatively low mean retention values that were not statistically significantly different at each quantity of compressive cyclic loading. Compressive cyclic loading had a statistically significant effect on Panavia-F specimens alone, but increased loading quantities produced no further statistically significant difference in mean retention. Compressive cyclic loading had no overriding statistically significant effect on the retention of all specimens as a population. Conclusions Within the limitations of the current in vitro conditions employed in this study, the retention of cast crown copings cemented to Straumann synOcta implant abutments with Panavia-F, KetacCem, and TempBond non-eugenol was significantly affected by cement type but not compressive cyclic loading. Panavia-F is the cement of choice for the definitive non-retrievable cementation of cast crown copings to Straumann synOcta implant abutments out of the three cements tested. The implications of these results relate to the choice of cement to provide the desired crown coping retention. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1349966 / Thesis (D.Clin.Dent.) -- University of Adelaide, School of Dentistry, 2008
2

Effect of surface treatment and fatigue on retention strength of titanium abutment to zirconia

Otsubo, Yuko 25 October 2017 (has links)
The objective of this study was to compare effect of surface treatment and fatigue to the retention of zirconia crowns luted to two different heights of titanium abutments. Thirty titanium base 3.5 mm (n = 15) and 5.5 mm in height (n = 15) and thirty zirconia crowns were used. Group A (n = 10), 3.5-mm-height titanium base with no surface treatment; Group B (n = 5), 3.5-mm-height titanium base with surface treatment; Group C (n = 5), 3.5-mm-height titanium base with no surface treatment with fatigue test; Group D (n = 5), 3.5-mm-height titanium base with surface treatment and fatigue test. The identical group allocation was utilized to 5.5-mm-height titanium base groups, Group E, F, G and H respectively. All zirconia crowns and titanium abutments of the groups with surface treatment were particle abraded with 50 μm alumina. All specimens were subjected to a pull-out test. Data were analyzed with ANOVA and the Tukey HSD test. Pull-out retention forces for each group were: Group A: 288 ± 97.5 N, Group B: 198.71 ± 82.94 N, Group C: 537.61 ± 80.13 N, Group D: 600.11 ± 27.23 N, Group E: 240.68 ± 54.33 N, Group F: 270.92 ± 16.43 N, Group G: 707.03 ± 32.30 N, and Group H: 831.19 ± 55.50 N. Particle abrasion of the titanium base significantly increased zirconia crown retention. The height of the titanium base had a significant influence on retention force in particle-abraded groups. The fatigue test did not decrease retention force. / 2018-09-26T00:00:00Z

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