Virtual surgical planning (VSP) and computer-aided design (CAD) are more frequently used in orthognathic surgery. During the past decade, VSP has developed rapidly, and the use of patient-specific implants (PSIs) and surgical guides has increased, with them now available in everyday practice. The creation of more sophisticated and freely designed implants has become possible with the development and commercial availability of CAD and computer-aided manufacturing (CAM) (Gander et al., 2015; Mazzoni et al., 2015; Suojanen et al., 2016, 2017). In complex asymmetry cases and bimaxillary surgery, the benefits of the use of VSP and CAD/CAM surgical tooling are clear (Ajmera et al., 2021; Hertanto et al., 2021; Peleg et al., 2021; Yoshikawa et al., 2022; Choi et al., 2023). It has been reported earlier that PSIs are accurate and functional tools for repositioning and fixation in Le Fort I osteotomy (Suojanen et al., 2016, 2018; Heufelder et al., 2017; Kotaniemi et al., 2019; Rückschloß et al., 2019; Kraeima et al., 2020; Jones et al., 2022).

Regarding the use of three-dimensional (3D) surgical planning and PSIs in bilateral sagittal split osteotomies (BSSOs), few data are available. The clinical benefits of using osteotomy and drill guides in combination with PSIs in BSSO are considerably more limited compared with the use of PSIs in Le Fort I osteotomy, and the benefits of PSIs with regard to final positioning and stability during BSSO are not yet as clear (Suojanen et al., 2017). There are some promising results in using VSP and PSIs in mandible-first bimaxillary surgery (Badiali et al., 2021; Trevisiol et al., 2023). Minor modifications to preoperative imaging protocols and more limited condylar rotation during VSP may provide more accurate results in CAD/CAM-guided BSSO (Järvinen et al., 2021). CAD/CAM-produced titanium PSIs also seem not to differ in terms of their localized long-term complication profile when compared with conventional mini-plate systems after BSSO (Suojanen et al., 2019).

The aim of this study was to compare the postoperative skeletal stability of the mandible after BSSO fixed either with PSIs or conventional mini-plates.