Accuracy of PSI-based hybrid workflow using a temporary intermediate splint versus conventional splint-based maxillary positioning in orthognathic surgery: a retrospective cohort study
The PSI-based hybrid workflow resulted in statistically greater positioning accuracy compared to conventional splint-based fixation, however, the absolute improvements were small, likely of limited clinical relevance, and were not associated with reduced operating times.
Abstract
This retrospective cohort study, adhering to STROBE guidelines, compared the accuracy of maxillary positioning achieved with a patient-specific implant (PSI)-based hybrid workflow, which utilised a temporary intermediate splint to identify and remove posterior bony interferences before definitive splintless PSI fixation, to conventional splint-based positioning using stock titanium osteosynthesis plates in orthognathic surgery. Translational and rotational movement deviations from the virtual surgical plan were assessed. Twenty-six patients who underwent non-segmental Le Fort I osteotomy between January 2020 and June 2023 were included. Eleven patients received the PSI-based hybrid workflow, while 15 patients underwent conventional splint-based positioning. Group allocation was based on the logistical feasibility of PSI planning and manufacturing rather than randomisation. Pre- and postoperative 3D images were superimposed using IPS® Case Designer software (KLS Martin) to quantify deviations in three translational and three rotational axes. Between-group comparisons were conducted using unpaired t-tests and two-way ANOVA, and correlations were assessed using Pearson’s coefficient. The mean translational deviation was significantly lower in the PSI group compared to the control group (0.46 ± 0.33 mm vs 0.79 ± 0.58 mm; p = .0044), as was the mean rotational deviation (0.82° ± 0.91° vs 1.24° ± 0.85°; p = .0397). Significant differences were identified for vertical translation (p = .0162) and yaw rotation (p = .0205). Operating time did not differ significantly between groups (p = . 1739). In the PSI group, greater planned displacement showed a weak correlation with larger deviations, a relationship not observed in the control group. The PSI-based hybrid workflow resulted in statistically greater positioning accuracy compared to conventional splint-based fixation. However, the absolute improvements (approximately 0.3 mm and 0.5°) were small, likely of limited clinical relevance, and were not associated with reduced operating times. Due to the retrospective, non-randomised design, small sample size, and use of a PSI-based hybrid protocol, these findings should be considered hypothesis-generating. Larger prospective studies evaluating fully splintless PSI workflows and patient-centred outcomes are recommended. Not applicable.
BACKGROUND
Orthognathic surgery increasingly relies on digital transfer workflows, most commonly CAD/CAM occlusal splints or patient-specific implants (PSI). However, prior meta-analyses were limited by methodological heterogeneity, sparse randomized evidence, and insufficient axis-specific analyses, leaving the magnitude and clinical relevance of any accuracy advantage unclear. This systematic review and meta-analysis aimed to compare PSI and CAD/CAM splint workflows in orthognathic surgery.
METHODS
This study followed PRISMA 2020 guidelines and was registered in PROSPERO (CRD420251039754). PubMed, Embase, and Cochrane were searched from inception to August 23, 2025. Comparative clinical studies evaluating PSI versus CAD/CAM splints in orthognathic surgery were included. Outcomes included linear accuracy, angular accuracy, operative time, and postoperative complications. The primary linear accuracy outcomes were axis-specific translational deviations across the mediolateral, anteroposterior, and superoinferior directions. Angular accuracy was assessed across pitch, roll, and yaw. Randomized trials were assessed using RoB 2.0, and non-randomized studies using the Newcastle-Ottawa Scale.
RESULTS
Thirty studies (12 RCTs and 18 cohort studies; 1317 patients) were included; 21 provided sufficient quantitative data for meta-analysis and 9 were synthesized narratively. Compared with CAD/CAM splints, PSI was associated with smaller axis-specific linear deviations across all three translational axes (all P < 0.01); a supportive combined linear summary showed the same direction but was not treated as a primary outcome. A possible advantage in angular accuracy was suggested (MD - 0.54°, 95% CI - 1.07 to - 0.01), but this was based on only six maxillary comparisons and should be interpreted cautiously. No statistically significant difference in postoperative complications was detected (RR = 1.01, 95% CI 0.64-1.60, P = 0.959). For operative time, current evidence did not demonstrate a statistically significant difference between workflows; however, few studies and substantial heterogeneity precluded firm conclusions.
CONCLUSION
Compared with CAD/CAM splints, PSI workflows were associated with smaller axis-specific translational deviations, while the available angular evidence suggests possible but limited rotational advantages. Current evidence remains inconclusive regarding operative time and does not demonstrate a significant difference in complication rates. PSI may be considered selectively in cases requiring high transfer precision; further studies should assess long-term stability and patient-reported outcomes.
Conventional plate osteosynthesis is the corner stone for management of displaced parasymphyseal mandibular fractures that necessitate open reduction and internal fixation (ORIF). Yet, the conventional workflow is labor-intensive, time consuming and limited by variable reduction accuracy as it relies solely on surgeon experience. Recently, various novel computer-guided techniques have been introduced for mandibular fracture repair, hiring surgical guides of diverse designs and strategies. These techniques served as a substitute for the conventional treatment modalities, offering improved precision, speed and reproducibility. Therefore, this randomized controlled trial (RCT) compares the overall precision of this distinct complete computer-guided virtual surgical planning (VSP) protocol as a whole, employing screw-holes locator and custom-made plates versus the conventional workflow for parasymphyseal mandibular fracture repair. Twenty-six cases presented with uncomminuted parasymphyseal mandibular fracture were enrolled and randomized into two groups. The interventional group underwent ORIF utilizing a screw-hole locator and custom-made plates, while the control group utilized ready-made mini-plates for ORIF. In both groups, virtual surgical planning of the fractured mandible was accomplished, creating a virtual reduced model by Mimics software aided by preoperative computer tomography (CT) scan. Then, three-dimensional model derived from the postoperative CT scan was superimposed onto the VSP reduced model. Linear deviations between predefined dental and bony landmarks to established anatomical planes were measured and underwent statistical analysis. The actual postoperative mandibular model in the computer-guided group demonstrated negligible deviation from the VSP model. While the conventional group revealed considerably greater deviation. The average deviation of the bony landmarks was 0.044 ± 0.14 mm for the intervention group versus 0.69 ± 0.5 mm for the control group (p < 0.001). The average deviation of the dental landmarks was 0.04 ± 0.13 mm for the intervention group versus 0.47 ± 0.33 mm for the control group (p < 0.001). The average surgical time of the intervention group was 1.46 ± 0.18 h versus 1.80 ± 0.34 h for the control group (p = 0.004), with the intergroup difference being statistically significant. The integration of screw-holes locator and patient-specific implants (PSI) have improved anatomical reduction precision, facilitated reestablishment of the patient’s native occlusion and ensured more standardized reproducible outcomes, especially beneficial for less experienced surgeons. The study is a randomized control trial, registered at ClinicalTrials.gov Protocol Registration and Results System Receipt, NCT05647460, Data: 2022–12-05.
Ahmed Abdellatif, H. Hatem, M. Elhadidy et al.· BMC Oral Health· 0 citations
OBJECTIVE
Accurate transfer of implant positions is critical for achieving passive fit in complete-arch implant-supported prostheses. This clinical case report describes the comparison of eight implant-position acquisition workflows and their influence on the clinical seating of mandibular complete-arch frameworks. The Clinical Seating Score (CSS) was used to assess clinical seating and was compared with three-dimensional deviations.
METHODS
A patient receiving mandibular All-on-4 rehabilitation was treated with four implants placed using dynamic navigation. After a 3-month healing period, implant positions were recorded using eight workflows: conventional open-tray impression, intraoral scanning with conventional PEEK, reduced-height titanium, horizontal-arm, centrally oriented, and reverse scan bodies, intraoral photogrammetry, and extraoral photogrammetry. Eight titanium frameworks were fabricated using standardized CAD/CAM procedures and evaluated intraorally by a single experienced clinician using the CSS (0-6), which assessed framework rocking, screw-tightening tension, and a modified Sheffield test. A Clinical Acceptability Bonus (+1) was assigned when predefined clinical deliverability criteria were met. The framework with the highest CSS was used as the reference for three-dimensional deviation analysis.
RESULTS
Intraoral photogrammetry produced the highest CSS (6 + 1) and was used as the reference framework. Centrally oriented scan regions and extraoral photogrammetry also produced clinically acceptable seating. Conventional impressions and workflows using conventional PEEK, horizontal-arm, or reverse scan bodies showed greater variability in clinical seating. Deviations of approximately 50-60 μm were generally associated with clinically acceptable seating, whereas discrepancies exceeding approximately 70-80 μm were associated with lower CSS values. These observations suggest that the clinical effect of implant-position discrepancies may vary according to their spatial direction.
CONCLUSIONS
Within the limitations of this single clinical case, the CSS provided a structured approach for assessing the clinical seating of complete-arch implant frameworks. Intraoral photogrammetry demonstrated the most favorable clinical seating, while other workflows showed variable outcomes. The proposed CSS and observed deviation ranges should be considered exploratory and require validation in larger clinical studies.
CLINICAL SIGNIFICANCE
The CSS may potentially provide a simple and standardized chairside method for evaluating the passive seating of complete-arch implant frameworks. This approach may help clinicians identify clinically relevant misfits before delivery of the definitive prosthesis and support more predictable decision-making during framework verification.
Francesco Mintrone, F. Ferri, Rostyslav Havryltsiv et al.· Journal of Esthetic and Rest...· 0 citations
Precise orthodontic pre-surgical decompensation is a critical prerequisite for optimal outcomes in orthognathic surgery. However, the relative effectiveness of completely customized lingual appliances (CCLAs) versus prefabricated vestibular multibracket appliances (PVMAs) remains insufficiently established. This study compared the decompensation efficiency, treatment quality, and overall clinical performance of these two appliances. The study included 60 consecutive patients who underwent orthodontic-orthognathic surgery: 30 with CCLA and 30 with PVMA. To ensure quality, the digital ABO CRE for each scanned model was evaluated using OnyxCeph3™ diagnostic software, and the efficiency of each appliance was recorded in the respective patient files. Both groups underwent the same evaluation protocol involving initial, intermediate (pre-surgery) and final casts. An additional set-up model was included for the CCLA group only. Both groups exhibited comparable baseline scores (mean difference 5.83; 95% CI 1.69 to 9.98). CCLAs demonstrated lower ABO scores than the PVMA group after the decompensation phase (mean difference − 9.23; 95% CI -13.38 to -5.09) and in the final assessment (mean difference − 9.30; 95% CI − 13.44 to -5.16). The largest differences between groups were observed for the alignment criteria in both jaws at the intermediate and final assessments, as well as for all intermaxillary criteria. Treatment efficiency particularly during the decompensation phase, was significantly improved in the CCLA group. CCLAs demonstrated superior efficiency and higher treatment quality compared with PVMAs in patients undergoing combined orthodontic–orthognathic therapy. The use of CCLAs in combination with orthognathic surgery appears to represent a high-quality treatment approach for correcting pronounced skeletal discrepancies and may serve as a reliable alternative to PVMA in appropriately selected patients.
F. Lang, N. Lang, Gwendolyn Isabella Lode et al.· Progress in orthodontics· 0 citations
Virtual surgical planning (VSP) and custom-made plates (patient-specific implants, PSIs) are increasingly used in mandibular fracture repair, but quantitative data on plan–execution fidelity remain limited. Plan–execution fidelity refers to the geometric agreement between the virtually planned and postoperative mandibular morphology after image registration. The aim of this pilot study was to quantify plan–execution fidelity and to describe patient-reported recovery in a fully digital, custom-plate workflow for non-comminuted mandibular fractures, while generating hypotheses about plate design. Six patients with non-comminuted mandibular body or parasymphyseal fractures underwent open reduction and internal fixation (ORIF) using a fully digital workflow. Plan–execution fidelity (the primary feasibility outcome) was assessed as the mean absolute error (MAE) of 10 predefined measurements after iterative closest point (ICP) registration on the contralateral ramus and condyle (condylar metrics excluded a priori). Measurements were performed by three blinded observers. The Oral Health Impact Profile-14 (OHIP-14) was recorded preoperatively and at 1, 4, and 12 weeks. Analyses are purely descriptive; no inferential statistics are reported. In this six-patient cohort, the primary (patient-level) MAE ranged from 0.25 to 0.81 mm (mean 0.48 mm, SD 0.21 mm). At the level of individual measurements (60 readings from the same six patients), the MAE was 0.45 mm. OHIP-14 total scores improved from 48.2 (SD 5.6) preoperatively to 5.2 (SD 4.1) at 12 weeks. Plate design, indication, and chronological order were structurally confounded; therefore, no comparative interpretation is possible. In this pilot cohort, a fully digital workflow using custom-made plates was associated with submillimetre plan–execution deviation (mean 0.48 mm) within the registration framework used. The workflow was technically feasible and showed close correspondence between the virtual plan and postoperative morphology, although this geometric agreement should not be interpreted as independent anatomical accuracy. These preliminary findings provide a basis for future controlled studies aimed at validating clinical relevance, workflow efficiency, and cost-effectiveness in larger patient cohorts. ClinicalTrials.gov NCT07499726; registered 24 March 2026 (2026-03-24), retrospectively, after initiation of recruitment.
Riad Kamal Riad, Eman Shalaby, Hesham El-Hawary· BMC Oral Health· 0 citations
AIM
To compare the clinical outcomes of digitally assisted immediate implant placement in the posterior mandible using immediate (Type A) and delayed (Type C) loading protocols.
METHODS
Eighty-two patients requiring five-unit fixed partial dentures supported by three implants were consecutively enrolled. All cases were planned using a fully digital workflow integrating CBCT, intraoral scanning, and static computer-guided surgery. Only implants achieving adequate primary stability (insertion torque ≥25 Ncm and/or ISQ ≥60) were included. Patients were assigned to either immediate or delayed loading protocols. Implant survival, marginal bone loss (MBL), plaque index (PI), bleeding on probing (BOP), and probing depth (PD) were evaluated over variable follow-up periods according to the timing of patient enrollment and treatment completion.
RESULTS
A total of 246 implants were placed, yielding an overall survival rate of 97.5% with no significant differences between loading protocols. Mean MBL was 0.7 mm and remained comparable between groups. Peri-implant parameters, including PI, BOP, and PD, were stable throughout follow-up. Regression analysis identified restorative angles >30° as the only significant predictor of increased MBL.
CONCLUSION
Digitally guided immediate implant placement in the posterior mandible demonstrated high survival rates and favorable peri-implant outcomes with both Type A and Type C loading protocols.
CLINICAL SIGNIFICANCE
Type A loading may provide a predictable and time-efficient alternative to conventional delayed loading without compromising clinical outcomes.
Mohammed A. Elsawy, Mohammed T. Khater, Islam Kandil et al.· E -journal of dentistry· 0 citations
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