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Strain Gauge Analysis of Three Different Sagittal Split Ramus Osteotomy Modifications
Frederico Felipe Antonio de Oliveira Nascimento1, John Paul Stella2, Leandro Eduardo Klüppel3
1Unidade de Cirurgia e Traumatologia Bucomaxilofacial, Hospital de Base de Brasília, Setor Médico e Hospitalar sul 101, Área especial sem número, Brasília, 70330-150 DF Brazil.
Journal of Maxillofacial and Oral Surgery
|July 30, 2026
Summary
The Wolford sagittal split osteotomy (SSRO) design offers superior screw stability and load distribution compared to Epker and Wyatt designs. Screw 2 demonstrates the most consistent stability across all tested SSRO configurations.
Area of Science:
- Oral and Maxillofacial Surgery
- Biomechanical Engineering
- Orthodontics
Background:
- Sagittal split osteotomy (SSO) is a common procedure in orthognathic surgery.
- Fixation stability is crucial for successful SSRO outcomes.
- Different SSO designs may influence biomechanical stress distribution.
Purpose of the Study:
- To compare the biomechanical stability of three distinct sagittal split osteotomy (SSRO) designs under vertical load.
- To analyze screw deformation and stress distribution across Epker, Wolford, and Wyatt SSRO designs.
Main Methods:
- Thirty polyurethane hemimandibles were divided into three groups (n=10) based on SSRO design (Epker, Wolford, Wyatt).
- Standardized inverted-L screw fixation was applied to all specimens.
- Strain gauges measured screw deformation during vertical loading until failure; peak load and deformation were recorded and analyzed using the Kruskal-Wallis test.
Main Results:
- The Wolford design (Group II) exhibited the highest mean load and most even stress distribution, indicating superior stability.
- The Epker (Group I) and Wyatt (Group III) designs showed varied stress patterns and lower load resistance, with the Wyatt design demonstrating less stability and earlier failure.
- Screw 2 consistently showed the lowest deformation and highest stability across all tested designs.
Conclusions:
- SSRO design significantly impacts force distribution and fixation stability.
- Techniques preserving proximal segment thickness, like the Wolford and Epker designs, enhance load dissipation.
- The Wyatt design modification, with inverted-L fixation, demonstrated reduced stability, highlighting the importance of surgical planning for optimal outcomes.
