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A validation of two orthognathic model surgery techniques
M A Bamber1, M Harris, C Nacher
1Department of Oral and Maxillofacial Surgery, Eastman Dental Institute for Oral Health Care, Sciences, University College London, 256 Grays Inn Road, London WC1X 8LD, UK. A.Bamber@eastman.ucl.ac.uk
Journal of Orthodontics
|June 8, 2001
Summary
The Eastman technique demonstrated superior accuracy in model surgery for orthognathic planning compared to the Lockwood keyspacer, particularly in vertical positioning. While both methods showed small variations, Eastman
Area of Science:
- Oral and Maxillofacial Surgery
- Orthodontics
- Biomedical Engineering
Background:
- Orthognathic surgery planning requires accurate model surgery techniques.
- Two popular methods, Lockwood keyspacer and Eastman anatomically-orientated system, are commonly used.
- Evaluating their accuracy is crucial for evidence-based protocol development.
Purpose of the Study:
- To compare the accuracy of the Lockwood keyspacer and Eastman system in model surgery.
- To assess the precision of maxillary cast positioning according to treatment plans.
- To evaluate the accuracy of maxillary repositioning after simulated Le Fort I osteotomy.
Main Methods:
- A comparative study involving 15 patients with different malocclusion classes (II div 1, II div 2, III).
- Utilized Lockwood keyspacer and Eastman anatomically-orientated system for model surgery.
- Measured accuracy using Erickson's electronic caliper, analyzing variations from the treatment plan.
Main Results:
- The Eastman technique showed significantly higher accuracy in vertical plane positioning (P=0.0001).
- Eastman also demonstrated better anteroposterior accuracy (P=0.05) in initial positioning.
- Both techniques exhibited comparable accuracy after simulated osteotomy, with Eastman slightly better in the vertical plane (P=0.001).
Conclusions:
- The Eastman anatomically-orientated system is relatively more accurate for orthognathic model surgery, especially in the vertical plane.
- While variations were generally small, some could be clinically significant.
- Findings support the Eastman technique for developing evidence-based orthognathic surgery planning protocols.