Evidence map of mixed reality as templates in orthognathic surgery: a scoping review

Background This scoping review mapped the use of mixed reality and augmented reality (MR/AR) as intraoperative navigation-transfer templates in orthognathic surgery. PubMed, Embase and the Cochrane Library were searched from inception to 19 September 2026, supplemented by a manual/citation search; screening and data charting were performed independently by two reviewers, with disagreements resolved by a third. Results Searches identified 364 records (363 from databases, 1 via citation searching); after removing 13 duplicates and screening 350 records, 23 reports were sought for retrieval (0 not retrieved) and assessed for eligibility, of which 3 were excluded. Twenty studies were included (19 from databases, 1 from citation searching; 12 clinical and 8 preclinical/phantom studies). MR/AR was used mainly for osteotomy-line transfer, maxillary or mandibular segment repositioning, occlusion verification, and plate or patient-specific implant (PSI) fixation. Optical-see-through head-mounted displays, especially HoloLens or HoloLens 2, were the most frequently reported platform, and marker-based registration predominated over markerless teeth- or surface-matching approaches. Reported accuracy varied by error type and workflow task and is presented separately for registration/tracking error, surface-distance error and postoperative repositioning error rather than as a single pooled range. Twelve of 20 studies were single-arm accuracy studies assessed only against a reference standard (planned virtual surgical plan vs. postoperative imaging), and 8 of 20 included a concurrent comparator arm. Conclusions MR/AR is used mainly as an intraoperative adjunct for transferring the virtual surgical plan in orthognathic surgery. The available evidence suggests technical feasibility and generally sub-millimetre-to-2 mm deviations under favourable conditions, but remains heterogeneous and dominated by small, early-phase, largely single-arm studies; it should not be read as a validated or pooled accuracy estimate. Well-designed comparative studies with standardized, clinically anchored outcome thresholds are still needed.