Biomechanical assessment of the maxillary position after Le Fort I osteotomy using rapidly biodegradable miniplates and screws: an experimental study

Absorbable plates have become increasingly common in orthognathic surgery. Multiple plate types are available, including poly-L-lactic acid (PLLA) and PLLA/polyglycolic acid (PGA), the latter of which is expected to be absorbed more rapidly. However, the application of these materials in Le Fort I osteotomy is not clearly established. In this study, the strength and biomechanical properties of PLLA and PGA-co-PLLA absorbable plates were compared using an in vitro LeFort I osteotomy model. Basic physical strength was evaluated using tensile, bending, indentation, and handling test s. Biomechanical evaluations using the Le Fort I osteotomy model included anterior (with 0, 3, and 5 mm anterior movement) and occlusal (with a 2 mm downward vertical movement) indentation tests. In terms of basic physical properties, PLLA showed significantly higher strength than that of PGA-co-PLLA in tensile, bending, and indentation tests. In handling tests, PGA-co-PLLA demonstrated superior performance. In biomechanical evaluations, no significant differences were observed between PLLA and PGA-co-PLLA in anterior or occlusal indentation testing. Despite the greater basic physical strength of PLLA than PGA-co-PLLA, there were no significant differences between the two plate types in the biomechanical evaluation of Le Fort I osteotomy. These findings provide a basis for plate selection in clinical practice.