الفهرس 
AcknowledgementOnly 14 pages are availabe for public view
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Abstract
Background:
The aim of this study was to assess the stability of a newly designed cortical mini-screw compared to three commercially available mini-screws.
Materials and Methods:
72 orthodontic mini-screws were used in maxilla and mandible of 9 Golden Retriever dogs. These screws were distributed as 54 commercially available self-drilling orthodontic mini-screws from three different companies and 18 newly designed cortical mini-screws. The stability of the mini-screws was tested at the insertion and after 8 weeks using Periotest (Siemens AG, Bensheim, Germany). CBCT scan was done for one of the dogs and uploaded into Anatomage 3D software, the length of mini-screws engaged into the bone were measured.
Results:
The overall success rate of the cortical type mini-screw was 77.78%. The success rate of three commercial group was about 77.77%. The initial Periotest values and final Periotest values showed highly significant improvement in the stability of all
groups, and showed no difference between the maxilla and mandible as location of insertions. Mean final Periotest values (-4.28) showed high improvement in stability of the cortical mini-screws group compared with the three commercially available orthodontic mini-screws group. The CBCT measurement showed total length of cortical mini-screws engaged in the bone was 1.60 mm, which was shorter than total length of the commercial orthodontic mini-screw engaged in the bone 6.05 mm.
Conclusions
from the results of the current study, the following conclusions can be stated:
1. The overall success rate of the newly designed cortical mini-screw group was 77.78%, and it was compared to the tested three commercially available mini-screws (77.77%).
2. The initial stability of newly designed cortical mini-screw was significantly less than tested three commercially available mini-screws as verified from Periotest values.
3. The final stability of newly designed cortical mini-screw was significantly improved compared to three commercially available mini-screws.
4. There was no effect of the location of mini-screws insertion on the tested mini-screws stability.