الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 158 |  |  |
| | | from | 158 | | |
Abstract
Summary and Conclusion OMIs are intraoral skeletal anchorage devices designed to provide direct or indirect anchorage during biomechanical orthodontic tooth movements. OMIs stability is a key for successful orthodontic treatment. A growing number of studies have reported approximately 13.5–16.4 % failure rate of the placed mini-implants. To ameliorate failure rates, OMIs could be optimized by modifying their own characters. Surface modification of OMIs is not a new idea, but various ways have already been tested and reported as effective both in animal and human studies. The aim of this work was to study the effect of different surface treatment techniques on the changes in their surface topography and their ions release in simulated human body fluid. Moreover, evaluation of OMIs primary stability in a prepared bovines’ femoral bone blocks using Perio-test® and Pull-out test. The current study was conducted on 36 OMIs having the following criteria’s; tapered type screw, button shaped head with two holes, machined smooth surface, 6 mm length, 1.6 mm diameter and made from biocompatible Grade 5 titanium alloy. They were divided into 3 groups; one machined as a control and the other two groups were undergoing two different surface treatment protocols; sand-blasting, acid-etching and anodic oxidation (SLAO) versus CO2 laser radiation method. All OMIs surface topography were examined under SEM to evaluate the effects of different methods of surface treatment. After that, all OMIs groups were immersed in SBF for the evaluation of surface treatment effects on their surface ions release (titanium, aluminum and vanadium) after 24 hours and 4 weeks of immersion using atomic absorption spectrometer. In addition to that, all of them were inserted in to a prepared bovine bone blocks (all bone blocks were within the same average mineral density, which was detected using cone beam computed tomography radiograph), for the purpose of measuring their primary stability, as a significant of their surface treatment using Perio-test® and Pull-out test methods. According to SEM examination results, each surface treatment method (sand-blasting, acid-etching, anodic oxidation and CO2 laser radiation) has its own effect on OMIs surface topography through increasing their surface roughness and subsequently increasing their surface area. One-way ANOVA test was used to compare mean of more than two groups, while post hoc LSD test was used for in-between groups comparison for each of: ions release tests, Perio-test® and Pull-out test results. Regarding to our study, the released titanium, aluminum and vanadium ions results within 1st day and 30th day in SBF from the studied OMIs were significantly below the average of daily dietary intake of these elements (not within a toxic concentration) and there was no statistically significant difference among all the studied OMIs groups, but ions release among OMIs studied groups achieved statistically significant difference on their titanium and aluminum ions release results, which increased in the 1st day more than the 30th day of SBF examination with the least vanadium released ions detection. On the other hand, the different studied surface treatment methods in the current work have significant effects on OMIs primary stability. This was explained by the increased roughness and surface area of OMIs, which increase their mechanical interlocking within the bone that inserted in. Regarding the evaluation of Perio-test® values results of OMIs primary stability in the bovine bone block samples, all OMIs studied groups in our work have no statistically significant difference in Perio-test® values, which reported that OMIs surface treatment by the above methods has no effect on their Perio-test® values. Regarding the evaluation of pull-out test results of OMIs primary stability in the bovine bone block samples, pull-out test results among the studied OMIs groups achieved statistically significant difference indication. Accordingly, OMIs of SLAO group achieved the higher primary stability results of pull-out test followed by OMIs of lasered group and finally OMIs of the control smooth surface group. On the basis of our study design and outcomes, within the limitations of this study, it can be concluded that: Surface treatment methods have significant effects on orthodontic mini-implants surface roughness under SEM. Sand-blasting of OMIs left its surface with macro-roughness, acid-etching left OMIs surface with micro-roughness and the anodic oxidation of OMIs formed thick oxide layer with nano-roughness along OMIs surface. Regarding CO2 laser radiation surface treatment of OMIs, it increased their surface roughness by the presence of protrusions, bulges or bumps of different sizes and shapes along their entire irradiated surfaces. Regarding our study, the released titanium, aluminum and vanadium ions results within the 1st day and the 30th day in SBF from the studied OMIs were significantly below the average of daily dietary intake of these elements (not within a toxic concentration) and there was no statistically significant difference among all the studied OMIs groups. Grade 5 Ti-6Al-4V alloy OMIs surface treatment methods, which mainly utilized in the current work achieved statistically significant difference on their titanium and aluminum ions release results, which increased in the 1st day more than the 30th day of SBF examination with the least detection of vanadium ions release. Surface treatment of orthodontic grade 5 Ti-6Al-4V alloy OMIs by each of: sand-blasting, acid-etching, anodic oxidation (SLAO) achieved the higher primary stability results of pull-out test due to their higher roughness rate and the increased total surface area followed by CO2 laser radiation than machined surface OMIs.