PIEZOELECTRIC VERSUS CONVENTIONAL OSTEOTOMY IN ORTHOGNATHIC SURGERY: A SYSTEMATIC REVIEW STRATIFIED BY TIMING OF NEUROSENSORY ASSESSMENT AND BY WHAT WAS TIMED

Purpose Piezoelectric osteotomy is promoted because it should spare the inferior alveolar nerve, yet comparative studies disagree. We asked whether timing of assessment and what was timed explain it. Methods Systematic review per PRISMA 2020. PubMed/MEDLINE, Web of Science and LILACS were searched to 15 September 2026 for studies comparing piezoelectric or ultrasonic with conventional instrumentation in sagittal split, Le Fort I or bimaxillary surgery. Scopus screening is incomplete and no Scopus-only record contributes; Embase is unlicensed and CENTRAL unsearched. One reviewer screened; re-screening the PubMed set recovered five eligible studies missed on the first pass. Results Twenty-one comparative studies were identified, six absent from previous syntheses; one tabulated as comparative in the latest review was excluded as single-arm. Eight of nine assessments at three months or earlier favoured piezoelectric osteotomy, including both studies with extractable counts (risk ratios 0.52, 95% CI 0.31 to 0.87, and 0.47, 95% CI 0.23 to 0.94); the ninth, the only analysis adjusted for amount of mandibular movement, favoured the saw. From six months, three assessments found no difference and three favoured piezoelectric osteotomy. Operating time followed what was timed: shorter for the osteotomy in three studies, longer or unchanged for the procedure in four.