Accuracy of maxillary repositioning surgery using CAD/CAM customized surgical guides and fixation plates

The advent of three-dimensional imaging and computer-aided surgical simulation (CASS) have brought about a paradigm shift in surgical planning. The aim of this study was to assess the accuracy of maxillary repositioning surgery using computer-aided design and manufacturing (CAD/CAM) customized titanium surgical guides and fixation plates. Thirty consecutive adult patients, 13 male and 17 female, with a mean age of 29.2 years and 25.5 years, respectively, requiring Le Fort I maxillary osteotomy, with or without simultaneous mandibular surgery, were evaluated retrospectively. All orthognathic surgeries were performed by one experienced surgeon. The pre-surgical and post-surgical volumetric imaging were superimposed to assess the linear and angular differences between the planned and actual positions of the maxilla following surgery. With the use of the CAD/CAM titanium surgical guides and fixation plates, all surgical movements were within 2 mm and 4° of the planned movements, which is considered clinically insignificant. The overall root mean square error between the planned and actual surgical movements was 0.38 mm in the transverse dimension, 0.64 mm in the anteroposterior dimension, and 0.55 mm in the vertical dimension. In regard to the centroid of the maxilla, the absolute angular difference of the maxillary centroid was 1.06° in pitch, 0.47° in roll, and 0.49° in yaw. Maxillary repositioning surgery can be performed with high accuracy using CAD/CAM titanium surgical guides and fixation plates.     

Do patient-specific cutting guides and plates improve the accuracy of maxillary repositioning in hemifacial microsomia?

The aim of this retrospective study was to use computer-aided design and manufacturing (CAD/CAM) patient-specific plates and cutting guides for the waferless positioning and fixation of the maxilla after bimaxillary osteotomies in cases of hemifacial microsomia with condylar dysplasia or absence of the temporomandibular joint (TMJ), and to compare the results with the CAD/CAM fabricated surgical wafer by 3-dimensional analysis. Eighteen patients were selected from the hospital database, preoperative surgical planning and simulation were done on 3-dimensional computed tomographic models for all patients, and they were divided into Group I – in which CAD/CAM patient-specific cutting guides and plates were used; and Group II – in which CAD/CAM fabricated surgical wafers were used. Finally, the outcome was evaluated by comparing planned with postoperative outcomes. The largest discrepancies of the Le Fort I segment were 0.50 (0.18) mm in the anteroposterior direction and 0.82 (0.60)° in the yaw orientation with Group I. The largest discrepancies of the Le Fort I segment were 1.32 (1.40) mm in superioinferior direction and 8.48 (7.73)° in the yaw orientation with Group II. The CAD/CAM patient-specific cutting guides and plates proved to be reliable and have great value in improving the accuracy in repositioning the Le Fort I segment and in the efficacy of orthognathic treatment of hemifacial microsomia with condylar dysplasia or no TMJ. The CAD/CAM patient-specific cutting guides and plates are therefore a useful alternative to the wafer technique.     

A novel method of computer aided orthognathic surgery using individual CAD/CAM templates: a combination of osteotomy and repositioning guides

The maxilla is usually positioned during orthognathic surgery using surgical splints, which has many limitations. In this preliminary study we present a new computer-aided design and manufacture (CAD/CAM) template to guide the osteotomy and the repositioning, and illustrate its feasibility and validity. Six patients with dental maxillofacial deformities were studied. The design of the templates was based on three-dimensional surgical planning, including the Le Fort osteotomy and the repositioning of the maxilla, and were made using a three-dimensional printing technique. Two parts of the templates, respectively, guided the osteotomy and repositioned the maxilla during operation. The traditional occlusal splint was used to achieve the final occlusion with the mandible in the expected position. Postoperative measurements were made between maxillary hard tissue landmarks, relative to reference planes based on computed tomographic (CT) data. The results of the measurements were analysed and compared with the virtual plan. The preliminary results showed that we achieved clinically acceptable precision for the position of the maxilla (<1.0 mm). Preoperative preparation time was reduced to about 145 min. All patients were satisfied with the aesthetic results. Our CAD/CAM templates provide a reliable method for transfer of maxillary surgical planning, which may be a useful alternative to the intermediate splint technique. Our technique does not require traditional model surgery, scanning of dental casts, or recording of the CAD/CAM splint.     

Accuracy of mandible-independent maxillary repositioning using pre-bent locking plates: a pilot study

The double splint method is considered the gold standard for maxillary repositioning, but the procedure is lengthy and prone to error. Recent splintless methods have shown high repositioning accuracy; however, high costs and technical demands make them inaccessible to many patients. Therefore, a new cost-effective method of mandible-independent maxillary repositioning using pre-bent locking plates is proposed. Plates are bent on maxillary models in the planned position prior to surgery. The locations of the plate holes are replicated during surgery using osteotomy guides made from thermoplastic resin sheets. Pre-bent plates are subsequently fitted onto the maxilla, and plate holes are properly set to reposition the maxilla. The purpose of this study was to evaluate the accuracy of this method for maxillary repositioning and the reproducibility of the plate holes. Fifteen orthognathic surgery patients were evaluated retrospectively by superimposing preoperative simulations over their postoperative computed tomography models. The median deviations in maxillary repositioning and plate hole positioning between the preoperative plan and postoperative results were 0.43 mm (range 0–1.55 mm) and 0.33 mm (range 0–1.86 mm), respectively. There was no significant correlation between these deviations, suggesting that the method presented here allows highly accurate and reliable mandible-independent maxillary repositioning.     

Accuracy of maxillary positioning in bimaxillary surgery

The aim of the study was to investigate the accuracy of a modified pin system for the vertical control of maxillary repositioning in bimaxillary osteotomies. The preoperative cephalograms of 239 consecutive patients who were to have bimaxillary osteotomies were superimposed on the postoperative films. Planned and observed vertical and horizontal movements of the upper incisor were analysed statistically. The mean deviations of −0.07 mm (95% confidence intervals (CIs) −0.17 to 0.04 mm) for the vertical movement and 0.12 mm (95% CI −0.06 to 0.30 mm) for the horizontal movement did not differ significantly from zero. Comparison of the two variances between intrusion and extrusion of the maxilla did not differ significantly either (p = 0.51). These results suggest that the modified pin system for vertical control combined with interocclusal splints provides accurate vertical positioning of the anterior maxilla in orthognathic surgery.     

Precision of orthognathic digital plan transfer using patient-specific cutting guides and osteosynthesis versus mixed analogue–digitally planned surgery: a randomized controlled clinical trial

Over the last decade, the accuracy of three-dimensional computer-assisted orthognathic surgery has been investigated extensively. The absence of high-quality controlled trials, limited number of studies overall, and methodological flaws have hindered its use in general clinical practice. The aim of this study was to assess the accuracy of computer-assisted orthognathic surgery compared to the classic occlusal wafers. Eighteen patients were randomly allocated to two groups: CAD/CAM splints and patient-specific osteosynthesis were used for maxillary positioning in group 1; occlusal wafers fabricated on a semi-adjustable articulator were used in group 2. Patients were assessed for linear and angular deviations of maxillary position from the virtual plan using cone beam computed tomography scans. The CAD/CAM group showed mean deviations of 0.26 mm vertically, 0.17 mm anteroposteriorly, and 0.07 mm mediolaterally, while the classic wafer group showed mean deviations of 1.45 mm vertically, 1.31 mm anteroposteriorly, and 0.71 mm mediolaterally. Statistical analysis showed that the proposed workflow provided a significantly more accurate plan transfer compared to classic occlusal wafers. Despite the statistical significance, the clinical significance was less appreciated. However, this new technology facilitated cases with skeletal asymmetry, reduced operating times, and allowed a trainee surgeon to perform the procedure with great accuracy and minimal time. The main limitation was the high cost.     

Precision of maxillary repositioning during orthognathic surgery: A prospective study

The purpose of this study was to evaluate the accuracy of surgical splints and an external reference point to reposition the maxilla during orthognathic surgery. Before surgery, a radiological marker was inserted inside the orthodontic bracket of the first right maxillary molar. A surgical splint was utilized to reposition the maxilla in the sagittal and coronal planes after the osteotomy. The vertical position was established by measuring the distance between a Kirschner wire inserted at bony nasion and the orthodontic wire. Preoperative and postoperative cephalometric radiographs were obtained and manually traced. The radiological marker and the tip of the right maxillary incisor were used as specific landmarks. Their displacement on the pre- and postoperative radiographs was measured. The actual surgical movement of the maxilla was compared to the initial surgical planning. 23 patients met the inclusion criteria to participate in the study. The mean difference between the planned and executed movements of the maxilla was 0.1 mm (p = 0.71). The difference was not statistically significant for any given movements of the maxilla. The use of surgical splints made from model surgery combined with an external reference point at bony nasion is accurate methods for repositioning the maxilla during orthognathic surgery.     

Effect of computer-assisted design and manufacturing cutting and drilling guides accompanied with pre-bent titanium plates on the correction of skeletal class II malocclusion: a randomized controlled trial

This study was performed to assess the effect of correcting skeletal class II malocclusion based on the application of computer-assisted design and manufacturing (CAD/CAM) cutting and drilling guides accompanied with pre-bent titanium plates. Fifty patients with skeletal class II malocclusion were recruited into this prospective randomized controlled clinical trial and assigned to two groups. Patients underwent bilateral sagittal split ramus osteotomy directed by CAD/CAM cutting and drilling guides accompanied with pre-bent titanium plates (group A) or CAD/CAM splints (group B). Postoperative assessments were performed. Differences between the virtually simulated and postoperative models were measured. Patients in both groups had a satisfactory occlusion and appearance. More accurate repositioning of the proximal segment was found in group A than in group B when comparing linear and angular differences to reference planes; however, no significant difference was revealed for the distal segment. In conclusion, CAD/CAM cutting and drilling guides with pre-bent titanium plates can provide considerable surgical accuracy for the positional control of the proximal segments in bilateral sagittal split ramus osteotomy for the correction of skeletal class II deformities.     

Accuracy of analytic model planning in bimaxillary surgery

The purpose of this study was to assess our method of analytic model planning in achieving a planned maxillary advancement for the correction of a dentofacial deformity. A consecutive series of 20 patients who underwent bimaxillary orthognathic surgery, at a minimum, were included in the study group. For each study subject, consistent analytic model planning with splint fabrication was used to establish the desired horizontal repositioning of the maxilla. Using preoperative and 5-week postoperative lateral cephalometric radiographs, an analysis was designed to assess the difference between the planned and actual advancement of the maxilla. The average difference between the planned and actual 5-week postsurgical advancement of the maxilla was 0.6 mm (range 0.2–1.0, P > 0.05). There was a strong correlation between the two data sets (R = 0.96). The results of the study indicate that the described method of analytic model planning is reliable (within 1 mm) in achieving the planned level of maxillary advancement in bimaxillary orthognathic procedures.     

Virtual planning and CAD/CAM-assisted distraction for maxillary hypoplasia in cleft lip and palate patients: Accuracy evaluation and clinical outcome

The aim of this prospective study was to report the experience with a specific guided distraction protocol for the treatment of CLP patients with severe midface hypoplasia.From January 2016 to April 2019, six consecutive, non-growing, CLP patients with maxillary hypoplasia underwent a specific distraction protocol based on the use of VSP, CAD/CAM-generated surgical splints, cutting guides, prebent internal maxillary distractors, early removal of distractors, and acute callus manipulation and fixation.STL files for VSP, using multislice CT scans taken preoperatively (T0) and 3 months after distractor removal (T1) were superimposed using the free software 3D Slicer and Geomagic Wrap to evaluate the accuracy of maxillary repositioning and assess 3D bone changes. Clinical outcome was evaluated at the 1-year follow-up (T2).The patients and surgeon were satisfied with the occlusal and aesthetic outcomes. A maximum difference of 2 mm between the VSP and the actual surgical outcome was chosen as the success criterion for accuracy. The average linear difference for selected points was <2 mm in four patients and >2 mm in two patients. The average distance of the postoperative maxilla from the VSP model was 2.28 mm (median 1.85), while the average forward movement of the maxilla was 10.18 mmThe protocol used is effective and accurate in the correction of severe maxillary hypoplasia in CLP patients. Early removal of the distractor and stabilization with plates reduces patient discomfort and does not jeopardize stability. This protocol should be reserved for complex cases due to the costs of the procedure, which are not negligible.     

3D planning in mandibular fractures using CAD/CAM surgical splints — A prospective randomized controlled clinical trial

This randomized controlled trial assessed the role of CAD/CAM splints in achieving anatomic reduction of fractured fragments and ideal occlusion, in comparison with conventional splints.Patients diagnosed with displaced mandibular fracture and post-traumatic malocclusion were allocated to study and control groups by simple randomization. A standardized surgical approach was followed to expose the fractures. Reduction of fractures was carried out using CAD/CAM and conventional splints in the study and control groups, respectively. The parameters assessed were: occlusion, interfragmentary separation, fit of the splint, patient comfort, and surgeon comfort. Mann-Whitney U tests were used to compare the study and control groups. To compare the groups pre- and post-intervention Wilcoxon signed rank tests were used. Chi-square tests were applied for proportion comparisons. The sample consisted of 30 patients.The study group demonstrated superior clinical outcomes with regards to intraoperative reduction of fracture (p < 0.001; mean – 3.93, SD – 1.43), and to achieving intraoperative occlusion (p = 0.483) and postoperative occlusion (p = 0.224). Statistically significant improvements in both patient comfort (p < 0.001; mean – 0.20, SD – 0.41) and surgeon comfort (p < 0.001) were found in the study group. In conclusion, CAD/CAM splints improve precision in fracture reduction and restoration of occlusion through a simple fabrication process.     

Accuracy of splint vs splintless technique for virtually planned orthognathic surgery: A voxel-based three-dimensional analysis

PurposeThis study compared two transferring methods for virtually planned orthognathic surgery — the CAD/CAM intermediate splint and the customized surgical guide with fixation plates.MethodsThis was a prospective clinical study in which participants were consecutively recruited and underwent bimaxillary orthognathic surgery. They were divided into two groups based on the transferring method used. The pre- and postoperative CBCTs were aligned using voxel-based landmark-free registration, and the discrepancies for selected points were compared with the planned displacement of the virtually planned surgery. The maxilla and mandible were analyzed separately, and translation and rotation movements were considered.ResultsA total of 16 patients, divided into two groups of eight patients each, were included in this study. The splintless group was significantly more accurate for the translation movement along the x-axes for points A (p = 0.008; mean absolute error 0.527 ± 0.387 for the splint group and 0.137 ± 0.067 for the splintless group) and Ans (p = 0.045; mean absolute error 0.535 ± 0.446 for the splint group and 0.156 ± 0.002 for the splintless group). For the mandible there was a significant difference in accuracy along the x-axes for points B (p = 0.049; mean absolute errors 1.728 ± 1.181 and 0.697 ± 0.519 for the splint and splintless groups, respectively), LL3 (p = 0.049; mean absolute error 1.629 ± 0.912 and 0.851 ± 0.797 for the splint and splintless groups, respectively), LR3 (p = 0.049; mean absolute error 1.711 ± 0.906 and 0.844 ± 0.780 for the splint and splintless groups, respectively), with the splintless group being more accurate. For the rotation the splintless group was significantly more accurate along the y-axes (p = 0.04; mean absolute error 1.62 ± 0.78 and 0.49 ± 0.31 for the splint and splintless groups, respectively) and z-axes (p = 0.04; mean absolute error 0.63 ± 0.45 and 0.17 ± 0.05 for the splint and splintless groups, respectively) for the maxilla, while no significant difference was found for the mandible.ConclusionsOverall, the customized fixation plate system is more accurate than the intermediate CAD/CAM splint for transferring the virtual plan into the operation room.     

Contemporary management of complex craniofacial trauma: virtual planning,navigation and the novel thermoformed cage splints in a strategic,sequential, computer-guided protocol

IntroductionIt was the aim of the study to assess if computerized simulation and the use of thermoformed cage splints are useful to plan cases of complex craniofacial trauma.Materials and methodspatients with fractures in any of the thirds of the craniofacial skeleton and occlusion impairment. Virtual surgical planning with digital reduction of fractures, navigated planning, thermoformed cage splints were used in all cases. Surgical outcomes were evaluated by computing the surface deviation and occlusograms between planned and postoperative models.Results13 patients were enrolled in this study. Accuracy of bone repositioning was evaluated compared with the surgical planning. For the mandible, mean Root Mean Square Error (RMSE) was of 1.67 with a standard deviation (SD) of ±0.75 mm (p < 0.001); for the maxilla, average RMSE was of 0.88 with SD of ±0.52 mm (p < 0.001); and for midfacial and upper third bone segments, average RMSE was of 0.59 with SD of ±0.47 mm (p < 0.001)ConclusionsWithin the limitations of the study it seems that thermoformed cage splints might be a promising alternative to other well-established approaches for accurate occlusal restoration and can be fully integrated within the digital workflow.     

Accuracy of Le Fort I osteotomy in bimaxillary splint-based orthognathic surgery: focus on posterior maxillary movements

This retrospective study was performed to verify the accuracy of horizontal and vertical repositioning of the maxilla in bimaxillary osteotomy with a focus on posterior vertical displacement. Data from 39 orthognathic patients undergoing bimaxillary surgery including a one-piece Le Fort I osteotomy with pitch rotation and advancement at the University Hospitals of Leuven (Belgium), between January 2015 and April 2016, were included in the study. Preoperative and 1-week postoperative lateral cephalograms were digitized and imported into cephalometric software. Horizontal and vertical measurements of dental landmarks were used to assess the accuracy of maxillary repositioning, and errors were reported in terms of the mean and absolute mean. The horizontal advancements were randomly under- and over-corrected an average of 1.4 mm ± 1.2 mm. Vertical repositioning of the anterior maxilla followed the planning. A tendency for under-correction was found for posterior vertical intrusion of the maxilla. The same tendency towards under-correction of posterior maxillary inferior repositioning was detected when planned movements were greater than 3 mm. For all studied groups, no significant difference was found between the planning and the results achieved, validating the use of intermediate splints.     

Treatment of hemimandibular hyperplasia by computer-aided design and computer-aided manufacturing cutting and drilling guides accompanied with pre-bent titanium plates

PurposeThe treatment of hemimandibular hyperplasia (HH) is difficult by performing condylectomy and orthognathic surgery in one stage. This study investigated the clinical feasibility of treating HH with computer-aided design and computer-aided manufacturing (CAD/CAM) cutting and drilling guides and the pre-bent titanium plates to improve the accuracy of operation to avoid condyle reconstruction.Methods12 patients diagnosed with HH were included in this study from 2014 to 2018. Conservative condylectomy and bimaxillary orthognathic surgery were performed in all patients. The CAD/CAM cutting and drilling guides and the pre-bent titanium plates were used to guide surgeries. Follow-up and radiographic examinations were performed. The difference between virtually simulated and postoperative models was measured.ResultsAll patients got satisfactory and stable results, without complications or obvious relapse during follow-up. Occlusion relationship, temporomandibular joint function and facial symmetry were improved obviously after surgery. Comparison between simulated plans and actual postoperative outcomes showed that the surgical plans were transferred accurately.ConclusionsCAD/CAM cutting and drilling guides and the pre-bent titanium plates described in this paper can help transferring the results from computer simulation to the operating room accurately. Conservative condylectomy can be operated exactly matching bimaxillary orthognathic surgery for treating HH, avoiding condyle reconstruction.     

A new model of customized maxillary guide for orthognathic surgery: Precision analysis

PurposeTo evaluate the surgical accuracy of a new Maxillary Bone-Dental-Supported guide (MBDS) for osteotomy and maxillary positioning in orthognathic surgeries.Materials and methodsThe customized MBDS were prototyped through CAD-CAM technology (computer-aided design and manufacturing). The planning image (CT0) was superimposed on the computed tomography scan post-treatment (CT1) and the mean of positional differences between them were obtained tridimensionally at the axes: mediolateral (X), anteroposterior (Y) and vertical (Z).ResultsEleven patients were selected according to the inclusion and exclusion criteria. The mediolateral movement showed the best precision, with a greater mean difference of 0.34 mm at the CI point (central incisor) and less than 0.02 mm at the RM point (right molar). In the vertical direction, the largest mean discrepancy found was 0.50 mm and on the y-axis, anteroposterior, was 0.74 mm, as well as two at the CI point. The skeletal SNA point, on the other hand, showed the smallest average discrepancies: 0.10 mm (x-axis), 0.03 mm (y-axis) and 0 mm (z-axis). Overall, 99.24% of the discrepancies found were less than 2 mm.ConclusionOur results suggests that the double support, osseous and dental, present in that new guide, favored the positional stability of the maxilla and promoted better control of its vertical axis. Furthermore, the function of an osteotomy guide increases the predictability and security of the surgical procedure.     

Splintless orthognathic surgery in edentulous patients—a pilot study

The aim of this pilot study was to evaluate the accuracy and predictability of a splintless treatment protocol for edentulous patients undergoing orthognathic surgery in four consecutive cases. All operations were virtually planned, followed by computer-aided design of individual osteotomy guides and patient-specific fixation implants, which were three-dimensionally printed in titanium. In order to evaluate the discrepancy between the planned and the achieved postoperative result, the postoperative outcome was compared to the virtual treatment plan. Rotational and translational movement and discrepancies with the planned movements were quantified for the maxilla; the advancement was quantified for the mandible. For the maxilla, there was a mean translation discrepancy of 0.6 mm. With regard to rotation, there was a mean discrepancy of 1.9°, 0.1°, and 0.4° for pitch, yaw, and roll, respectively. The mean discrepancy in translation of the mandible was 0.4 mm. The results of this pilot study indicate that the splintless treatment protocol for orthognathic surgery in edentulous patients presented here is accurate and predictable.     

Quantification of the inaccuracy of conventional articulator model surgery in Le Fort 1 osteotomy: evaluation of 30 patients controlled by the Orthopilot® navigation system

Occlusal splints are commonly used to position the maxilla during traditional orthognathic surgery. We aimed to quantify the inaccuracy of the maxillary positioning (in three dimensions) in traditional model surgery with the Orthopilot^® navigation system. Thirty Le Fort I osteotomies were made using a standard technique. The position of the maxilla was recorded by the navigation system and defined by three values of translation and three of rotation. The recorded data were compared with the planned data. The accuracy of positioning was classified in distinct classes with three major criteria (conformity, non-conformity, and failure) according to the discrepancy. The positioning of the maxilla was in conformity with operative planning in 3/30 of our Le Fort I osteotomies (95% CI 2% to 27%) and in failure in 22/30 (95% CI 54% to 88%). The dispersion of the discrepancy was more important in the sagittal plane, particularly for the sagittal rotation and for the back-front translation, which reflected greater inaccuracy in this plan. The frontal orientation of the maxilla was better controlled. The risk of maxillary malposition was proportional to the planned maxillary advancement.     

Splintless surgery using patient-specific osteosynthesis in Le Fort I osteotomies: a randomized controlled multi-centre trial

The accuracy of orthognathic surgery has improved with three-dimensional virtual planning. The translation of the planning to the surgical result is reported to vary by >2 mm. The aim of this randomized controlled multi-centre trial was to determine whether the use of splintless patient-specific osteosynthesis can improve the accuracy of maxillary translation. Patients requiring a Le Fort I osteotomy were included in the trial. The intervention group was treated using patient-specific osteosynthesis and the control group with conventional osteosynthesis and splint-based positioning. Fifty-eight patients completed the study protocol, 27 in the patient-specific osteosynthesis group and 31 in the control group. The per protocol median anteroposterior deviation was found to be 1.05 mm (interquartile range (IQR) 0.45–2.72 mm) in the patient-specific osteosynthesis group and 1.74 mm (IQR 1.02–3.02 mm) in the control group. The cranial–caudal deviation was 0.87 mm (IQR 0.49–1.44 mm) and 0.98 mm (IQR 0.28–2.10 mm), respectively, whereas the left–right translation deviation was 0.46 mm (IQR 0.19–0.96 mm) in the patient-specific osteosynthesis group and 1.07 mm (IQR 0.62–1.55 mm) in the control group. The splintless patient-specific osteosynthesis method improves the accuracy of maxillary translations in orthognathic surgery and is clinically relevant for planned anteroposterior translations of more than 3.70 mm.     

Barcelona line. A multicentre validation study of a facial projection reference in orthognathic surgery

The purpose of this study was to validate an already published facial anteroposterior reference: upper incisor (UI) to soft tissue plane or so-called Barcelona line (BL) to trace the most aesthetic sagittal position of the maxilla. A cross-sectional multicentre evaluation of Caucasian patients from Spain and Brazil with different anteroposterior maxillary positions was designed. Sagittal images in natural head orientation of grouped patients according to the horizontal distance from the UI to BL were ranked by healthcare professionals and non-professional Caucasian raters according to the aesthetic perception of each profile, using a digital survey. Seventy-four raters (50 laypeople, 12 orthodontists, and 12 maxillofacial surgeons) rated 40 profiles. The best-rated profile corresponded to group 3 (0–4 mm UI-BL) with 61.8% of positive evaluations, followed by group 4 (≥ 4 mm UI-BL): with 61.1%. On the other hand, group 1 (≤?4 mm UI-BL) was the worst-ranked profile with 71.8% of negative evaluations, followed by group 2 (?4–0 mm UI-BL): with 59.6% of negative evaluations. The correlation between the mean assessment score and UI-BL showed a moderately-strong association (r = 0.68, p < 0.001). The inter-rater reliability of assessment (74 evaluators) was moderate (k = 0.49, 95% CI: 0.39 to 0.59). The results suggest that protrusive middle-third facial profiles are preferable. The BL is proposed as a simple, individualised, and reproducible tool to trace an aesthetic sagittal position of the maxilla in orthognathic surgery.