Comparison of piezosurgery vs. conventional bone chisel for extraction of impacted mandibular third molars with root-canal intimacy: a retrospective cohort study with CBCT-based preoperative planning

To compare clinical outcomes of piezosurgery vs. conventional chisel for extracting impacted mandibular third molars (IMTMs) with roots adjacent to the inferior alveolar nerve canal (IANC) under identical CBCT-based planning, isolating the ultrasonic osteotome's incremental benefit beyond shared imaging.

A retrospective comparative cohort study was conducted using the clinical data of 126 patients with IMTMs whose tooth roots were closely adjacent to the IANC and who were treated in the Department of Oral and Maxillofacial Surgery at our hospital between September 2025 and May 2026. All patients underwent CBCT three-dimensional reconstruction before the operation to evaluate the anatomical structure and formulate the surgical plan. The patients were divided into the piezosurgery (n = 63) and conventional surgery (n = 63) groups. The conventional surgery group underwent traditional bone chiseling and crown splitting for extraction, while the piezosurgery group underwent extraction using the ultrasonic bone knife minimally invasive technique. The operation time, intraoperative blood loss, pain visual analogue scale (VAS) scores at different time points after surgery, degree of facial swelling, degree of mouth opening limitation, and complication occurrence rate were compared between the two groups.

Compared with the conventional surgery group, the piezosurgery group exhibited a markedly shorter surgical procedure duration and a significantly reduced volume of intraoperative blood loss, with all between-group comparisons yielding statistically significant results (P < 0.05). There were interaction effects between the two groups and at different time points in the VAS scores, facial swelling differences, and mouth opening limitation differences (P < 0.05). The VAS scores, facial swelling differences, and mouth opening limitation differences in the piezosurgery group at 1 day, 3 days, and 7 days after surgery were all lower than those in the conventional surgery group (P < 0.05). Additionally, the incidence of adverse postoperative complications was markedly lower in the piezosurgery group than in the conventional surgery group, and this discrepancy was statistically significant (P < 0.05).

The CBCT-guided ultrasonic osteotome minimally invasive technique shortens operative time, reduces bleeding, alleviates postoperative pain, swelling, and trismus, and lowers complication rates in IMTM extraction with root-canal proximity.