Semester

Spring

Date of Graduation

2012

Document Type

Thesis

Degree Type

MS

College

School of Dentistry

Department

Orthodontics

Committee Chair

Mark Richards

Committee Co-Chair

Michael Bagby

Committee Member

Mohssen Ghalichebaf

Committee Member

Ali Kanawati.

Abstract

Purpose: The purpose of this study is to compare and contrast the difference between airborne-particle abrasion and two common commercially available opaquers during shear testing of clinical models. Comparisons between the type of failure (adhesive, cohesive, or mixed) and surface analysis of the airborne-particle abraded samples will be evaluated.;Materials and Methods: 16 identical Nobel Procera titanium alloy frameworks were manufactured to fit a master titanium block fitted with four multi-unit abutments. Metal-resin implant fixed dental prosthesis were manufactured to test surface preparations. The variables between framework groups were airborne-particle abrasion and opaquer type in a split sample design. Test groups 1 and 2 and 3 were airborne-particle abraded with aluminum oxide particles sized 100 micron, 250 micron, and Rocatec 30 micron silica modified aluminum oxide (3M ESPE) respectively. Specimens were randomly assigned right and left halves and treated with Ropak UV opaquer (Bredent) and Telio opaquer (Ivoclar Vivadent). Test groups four and five were treated entirely with Telio and Ropak opaquer as described above. The titanium frameworks, however, were divided at the midline and airborne-particle abraded with both 100micro and 250micro aluminum oxide particles. All specimens were mounted on a master titanium block fitted with replaceable multi-unit abutments. Specimens were each mounted at a 20-degree tilt to the horizon and placed in a universal testing machine at shear with a crosshead speed of .5mm/min until failure.;Tested specimens were examined with a surgical loupes (Designs for Vision) at X3.5 magnification for type of failure 1) adhesive, 2) cohesive, 3) mixed and graded as such (A, C, and M).SEM Surface Observation recorded at 250X, 3000X, and 27,000X. Specimens were also examined semi quantitatively with energy dispersive X-ray spectroscopy.;Results: A universal testing machine was utilized to test specimens to failure in shear with a crosshead speed of .5mm/min. Results were recorded graphically in Newtons/time with maximum load at failure. Maximum load at failure was recorded in Newtons for each specimen. Oneway analysis of variance (ANOVA) of force by group was performed and is graphically depicted in Chart 2. No statically significant difference was found among test groups. 100microm air particle abrasion group showed a slightly higher mean than the other abrasion groups. The Telio opaquer group was slightly higher than the Ropak group. This area was observed with X3 magnification and failure type was recorded in Table 1.;Conclusion: Within the limits of the study, the following conclusions can be drawn: The air-particle abrasion techniques utilized in this study resulted in no statistically significant difference in terms of load failure. The opaquer techniques utilized in this study resulted in no statically significant difference in terms of load failure. There were no cohesive failures observed in this study. Ropak demonstrated mixed failure when air-particle abraded with 100microm and 250microm aluminum oxide. Telio demonstrated mixed failure when air-particle abraded with Rocatec 30microm silica modified aluminum oxide.

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