Vora Sheelkumar, Rashmikumar (2012) Evaluation of angular deviation of miniscrew implants using cone beam computed tomography: An in vitro study. Masters thesis, Ragas Dental College and Hospital, Chennai.
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Abstract
Numerous anatomical sites for MSI insertion have been presented in the maxilla and mandible. The inter-radicular septum is considered as one of the most commonly used locations for MSI placement. Precise placement of MSI in the inter-radicular septum is important to achieve safety of the vital structure and stability. Successful MSI placement, in both the maxillary and mandibular regions, requires accurate angulation and position in order to achieve safety, mechanical retention and primary stability. A deviation from the planned MSI insertion axis in mesio-distal and vertical direction can occur as most clinicians generally insert MSI’s without a guide and place it free hand using only panoramic radiographs or periapical films to estimate the inter-radicular space, which inadvertently causes injury to roots of teeth and damage to other vital structures. Hence, this study was done to evaluate the factors influencing the angular deviation of MSIs using cone beam computed tomography. The study evaluated factors such as varying lengths of MSI, various diameters of MSI, different bone densities and method of MSI insertion. The conclusions drawn from this study are:- • Increase in MSI diameter from 1.3mm, 1.5mm and 2mm causes increase in the amount of angular deviation of MSI in mesio-distal direction (view 1) and in vertical plane (view 2). 2mm diameter showed the maximum amount of angular deviation in both the planes. • Increase in length of MSI from 6mm, 8mm and 10mm shows statistically significant increase in the amount of angular deviation of MSI in vertical plane (view 2). 10mm length MSI showed the maximum amount of angular deviation in the vertical plane (view 2). • Increase in bone density from 10pcf, 20pcf and 30pcf causes statistically significant increase in the amount of angular deviation of MSI in mesio-distal direction (view 1) and in vertical plane (view 2). Angular deviations of MSI were maximum with 30pcf bone density in mesio-distal plane (view 1) and 20pcf in the vertical plane (view 2). Amount of angular deviation of MSI for 20pcf and 30pcf were very similar and high and it is concluded that increase in bone density causes increase in angular deviation of MSI. • It is concluded that angular deviations with free-hand MSI insertion were high compared to guided MSI insertion in both mesio-distal (view 1) and vertical plane (view 2). Results of our study show that as length and diameter of MSI are increased the amount of angular deviation increases in both the horizontal plane (view1) and vertical plane (view 2). 20pcf and 30pcf bone density both showed the maximum amount of angular deviations of MSI in horizontal (view1) and vertical plane (view 2). MSI inserted by the surveyor method (guide) showed decreased amount of angular deviation as compared to the free-hand placement. However even with the guide method the angular deviations are still not completely eliminated Clinically, MSIs are not always inserted using guides and as CBCT is not routinely recommended, prior knowledge of length, diameter and bone density causing angular deviation of MSI would help the clinician select the correct MSI length and diameter, for the desired MSI insertion site and avoid injuring roots of teeth and other vital structures. Bone density showed the maximum Odd’s Ratio, denoting that it was the major factor causing angular deviation of MSI when compared to the length of MSI, diameter of MSI and the method of insertion of MSI. All these factors need to be taken into consideration before selecting the MSI for any desired placement site, to avoid injuring roots of teeth and surrounding vital structures and increase the success rate of the MSI. The primary limitation of this study pertains to the inability to directly transfer the effects identified into the clinical situation. While the synthetic bone used in the present study is well suited for controlling extraneous factors and focusing on the effects under consideration, but angular deviation of MSI in actual bone might show much more variable and might be expected to produce different magnitudes of difference. Experimental findings should be compared to clinical studies. In vitro measurements tend to more accurately describe the variable tested; however, they are far from simulating the actual clinical conditions. Clinical studies on the other hand, may report clinically applicable data, but do not provide an insight into the specific details of the research hypothesis.
| Item Type: | Thesis (Masters) |
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| Uncontrolled Keywords: | angular deviation ; miniscrew implants ; cone beam computed tomography ; in vitro study. |
| Subjects: | DENTAL > Orthodontics and Dentofacial Orthopedics |
| Depositing User: | Subramani R |
| Date Deposited: | 09 Oct 2018 15:27 |
| Last Modified: | 09 Oct 2018 15:27 |
| URI: | http://repository-tnmgrmu.ac.in/id/eprint/9798 |
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