Pull-out strength of monocortical screws placed in the maxillae and mandibles of dogs. American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics. [Am J Orthod Dentofacial Orthop] Journal article | | Title | Pull-out strength of monocortical screws placed in the maxillae and mandibles of dogs. | | Author(s) | Huja SS, Litsky AS, Beck FM, Johnson KA, Larsen PE | | Institution | Section of Orthodontics, College of Dentistry, The Ohio State University, 4088 E. Postle Hall, 305 W. 12th Avenue, Columbus, OH 43210, USA. huja.1@osu.edu | | Source | Am J Orthod Dentofacial Orthop 2005 Mar; 127(3):307-13. | | MeSH | Analysis of Variance
Animals
Bone Density
Bone Screws
Dental Implantation, Endosseous
Dental Stress Analysis
Device Removal
Dogs
Implants, Experimental
Mandible
Maxilla
Orthodontic Appliance Design
Palate, Hard
Regression Analysis
Research Support, Non-U.S. Gov't
Statistics, Nonparametric
Tensile Strength
Torque
| | Abstract | BACKGROUND: Mini-implants can facilitate orthodontic tooth movement by serving as anchors. The purpose of this investigation was to determine whether the pull-out strength of screws in bone varies depending on the site of insertion in the maxilla or the mandible. MATERIALS: Fifty-six titanium screws (2 mm diameter, 6 mm length, Synthes USA, Monument, Colo) were placed in 4 beagle dogs (14 screws per dog) within 30 minutes after they were killed. The screws were inserted to obtain monocortical anchorage, at predetermined sites in the anterior, middle, and posterior regions of the jaws bilaterally. Two screws were placed in the posterior palate in each dog. The jaws were harvested, and bone blocks, each containing a screw, were prepared for mechanical testing. The bone/screw block was aligned on a custom-made fixture, and the maximum force (F max ) at pullout was recorded. Cortical bone thickness was measured after extraction of the screw. Statistical analyses to test for differences were conducted with ANOVA and Tukey-Kramer tests.
RESULTS: Screws placed in the anterior mandibular region had significantly ( P < .05) lower F max (134.5 +/- 24N, mean +/- SE) than those placed in the posterior mandibular region (388.3 +/- 23.1N). Regression analyses suggested a weak (r = 0.39, P = .02) but significant correlation between F max and cortical bone thickness.
CONCLUSIONS: The bone supporting monocortical screws would most likely withstand immediate loading and support tooth-moving forces. | | Language | eng | | Pub Type(s) | Journal Article
| | PubMed ID | 15775945 |
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