The efficacy of Platelet and Leukocyte Rich Fibrin (L-PRF) in the healing process and bone repair in oral and maxillofacial surgeries: a systematic review.

INTRODUCTION: The search to optimize the healing and bone repair processes in oral and maxillofacial surgeries reflects the constant evolution in clinical practice, driven by the demand for increasingly satisfactory results and the need to minimize postoperative complications. OBJECTIVE: To evaluate the efficacy of Platelet and Leukocyte Rich Fibrin (L-PRF) in the healing and bone repair process in oral and maxillofacial surgeries. MATERIALS AND METHODS: The systematic review protocol for this study included the definition of the research question, the domain of the study, the databases searched, the search strategy, the inclusion and exclusion criteria, the types of studies to be included, the measures of effect, the methods for screening, data extraction and analysis, and the approach to data synthesis. Systematic literature searches were carried out on Cochrane databases, Web of Science, PubMed, ScienceDirect, Embase and Google Scholar. RESULTS: The strategic search in the databases identified 1,159 studies. After removing the duplicates with the Rayyan© software, 946 articles remained. Of these, 30 met the inclusion criteria. After careful evaluation based on the inclusion and exclusion criteria, 8 studies were considered highly relevant and included in the systematic review. CONCLUSION: Platelet and Leukocyte Rich Fibrin (L-PRF) has a positive effect on the healing process and bone repair in oral and maxillofacial surgeries.

Is there a difference in surgical accuracy following bimaxillary surgery between cleft and non-cleft patients?

OBJECTIVES: To assess the surgical accuracy of 3D virtually planned orthognathic surgery among patients with and without cleft. MATERIALS AND METHODS: This retrospective cohort study included cleft and non-cleft patients with class III malocclusion who underwent bimaxillary surgery. CBCT scans were acquired before and immediately after surgery. 3D virtual surgical planning (VSP) was performed using CBCT and digitalized dentition data. All orthognathic surgeries were performed by the same surgeons using interocclusal splints. The primary outcome variable was surgical accuracy, defined as the difference between the planned and surgically achieved maxillary movements, quantified in six degrees of freedom. Analysis of covariance was used to test for intergroup differences in surgical accuracy after correcting for differences in the magnitude of planned surgical maxillary movements. RESULTS: Twenty-eight cleft and 33 non-cleft patients were enrolled, with mean ages of 18.5 and 25.4 years, respectively (P=0.01). No significant gender difference was present between the groups (P=0.10). After adjustment for small differences in surgical movements, no significant differences in surgical accuracy were observed between cleft and non-cleft patients. CONCLUSION: The present study demonstrates that high surgical accuracy in maxillary movements can be achieved in both cleft and non-cleft patients using VSP and interocclusal splints. CLINICAL RELEVANCE: Orthognathic cases with cleft can be performed with 3D VSP to obtain a satisfactory surgical accuracy.

[Comparison of the virtual surgical planning position of maxilla and condyle with the postoperative real position in patients with mandibular protrusion].

OBJECTIVE: To compare the difference between virtual surgical planning (VSP) position and postoperative real position of maxilla and condyle, and to explore the degree of intraoperative realization of VSP after orthognathic surgery. METHODS: In this study, 36 patients with mandibular protrusion deformity from January 2022 to December 2022 were included. All the patients had been done bilateral sagittal split ramus osteotomy (SSRO) combined with Le Fort Ⅰ osteotomy under guidance of VSP. The VSP data (T0) and 1-week postoperative CT (T1) were collected, the 3D model of postoperative CT was established and segmented into upper and lower jaws in CCMF Plan software. At the same time, accor-ding to the morphology of palatal folds, the virtual design was registered with the postoperative model, and the unclear maxillary dentition in the postoperative model was replaced. Then the postoperative model was matched with VSP model by registration of upper skull anatomy that was not affected by the operation. The three-dimensional reference plane and coordinate system were established. Selecting anatomical landmarks and their connections of condyle and maxilla for the measurement, we compared the coordinate changes of marker points in three directions, and the angle changes between the line connecting the marker points and the reference plane to analyze the positional deviation and the angle deviation of the postoperative condyle and maxilla compared to VSP. RESULTS: The postoperative real position of the maxilla deviates from the VSP by nearly 1 mm in the horizontal and vertical directions, and the anteroposterior deviation was about 1.5 mm. In addition, most patients had a certain degree of counterclockwise rotation of the maxilla after surgery. Most of the bilateral condyle moved forward, outward and downward (the average distance deviation was 0.15 mm, 1.54 mm, 2.19 mm, respectively), and rotated forward, outward and upward (the average degree deviation was 4.32°, 1.02°, 0.86°, respectively) compared with the VSP. CONCLUSION: VSP can be mostly achieved by assistance of 3D printed occlusal plates, but there are certain deviations in the postoperative real position of maxilla and condyle compared with VSP, which may be related to the rotation axis of the mandible in the VSP. It is necessary to use patient personalized condylar rotation axis for VSP, and apply condylar positioning device to further improve surgical accuracy.

[Mandibular condyle localization in orthognathic surgery based on mandibular movement trajectory and its preliminary accuracy verification].

OBJECTIVE: To establish and assess the precision of pre-surgical condyle position planning using mandibular movement trajectory data for orthognathic surgery. METHODS: Skull data from large-field cone beam computed tomography (CBCT) and dental oral scan data were imported into IVSPlan 1.0.25 software for 3D reconstruction and fusion, creating 3D models of the maxilla and mandible. Trajectory data of mandibular movement were collected using a mandibular motion recorder, and the data were integrated with the jaw models within the software. Subsequently, three-dimensional trajectories of the condyle were obtained through matrix transformations, rendering them visually accessible. A senior oral and maxillofacial surgeon with experience in both diagnosis and treatment of temporomandibular joint disease and orthognathic surgery selected the appropriate condyle position using the condyle movement trajectory interface. During surgical design, the mobile mandibular proximal segment was positioned accordingly. Routine orthognathic surgical planning was completed by determining the location of the mandibular distal segment, which was based on occlusal relationships with maxilla and facial aesthetics. A virtual mandible model was created by integrating data from the proximal and distal segment bone. Subsequently, a solid model was generated through rapid prototyping. The titanium plate was pre-shaped on the mandibular model, and the screw hole positions were determined to design a condylar positioning guide device. In accordance with the surgical plan, orthognathic surgery was performed, involving mandibular bilateral sagittal split ramus osteotomy (SSRO). The distal segment of the mandible was correctly aligned intermaxillary, while the proximal bone segment was positioned using the condylar positioning guide device and the pre-shaped titanium plate. The accuracy of this procedure was assessed in a study involving 10 patients with skeletal class Ⅱ malocclusion. Preoperative condyle location planning and intraoperative positioning were executed using the aforementioned techniques. CBCT data were collected both before the surgery and 2 weeks after the procedure, and the root mean square (RMS) distance between the preope-rative design position and the actual postoperative condyle position was analyzed. RESULTS: The RMS of the condyle surface distance measured was (1.59±0.36) mm (95%CI: 1.35-1.70 mm). This value was found to be significantly less than 2 mm threshold recommended by the expert consensus (P < 0.05). CONCLUSION: The mandibular trajectory may play a guiding role in determining the position of the mandibular proximal segment including the condyle in the orthognathic surgery. Through the use of a condylar positioning guide device and pre-shaped titanium plates, the condyle positioning can be personalized and customized with clinically acceptable accuracy.

Is photobiomodulation effective during maxillary expansion? A systematic review and meta-analysis.

We performed a systematic review on literature associated with meta-analyses to elucidate whether (I) low-level laser therapy (C) compared to placebo accelerates (O) bone neoformation in the region of the midpalatal suture in (P) patients undergoing transverse maxillary expansion. Two reviewers blindly performed targeted searches using the selection criteria (PICOS) in seven major databases and three grey literature databases, employing specific terms and their entrenchments. The RevMan® software (Review Manager, version 5.3, Cochrane Collaboration) was used to adapt the RoB summary illustration to the Cochrane 2.0 tool questions. Meta-analysis was performed using standardized mean difference (SMD) and Cohen's d calculation on random effects, tests for heterogeneity (I2 ) and publication bias (Egger and Begg), and one-of-out sensitivity analysis. GRADE (Grading of Recommendations Assessment, Development and Evaluation) was used for evidence quality analysis. Among the five studies included in the qualitative synthesis, three were included in the meta-analysis. All analysed studies were prospective randomized clinical trials. The risk of bias was such that the Egger (P = .1991) and Begg (P = .024) tests showed no significant risk of publication bias. The meta-analysis showed high heterogeneity (I2  = 81%, P < .00001), and 3 months after the operation, there was no significant difference between the photobiomodulation (PBMT) group and control group (P = .850) or between the subgroups of the periods evaluated after 3 months (P = 0.490). GRADE showed an SMD of 0.62. Photobiomodulation as an adjuvant therapy in patients undergoing transverse maxillary expansion has few benefits and is limited in shape, as it contributes to bone healing in the midpalatal suture region after a period of 3 months.

Effects of modified step Le Fort I advancement surgery on nostril area and inferior nasal structures volume in class III patients: a retrospective clinical study.

OBJECTIVE: The effect of the modified step Le Fort I osteotomy on the inferior nasal structures and the nostril area was evaluated. MATERIALS AND METHODS: This study included 24 patients who had modified step Le Fort I osteotomy. Inferior nasal concha volume (INCV), meatus nasi inferior volume (MNIV), the sum of both structures volume (TV), and nostril area (NA) were evaluated in pre- (T0) and postoperative (T1) periods. RESULTS: For all patients, NA increased both on the right side (p = 0.011) and left side (p = 0.050) after surgery. The INCV and TV values were lower in T1 than those in T0; however, a statistically significant decrease of INCV and TV was found only in the right side of males (p = 0.039 and p = 0.050, respectively). No significant difference was found in MNIV between T0 and T1 measurements (p > 0.05). CONCLUSION: Maxillary advancement with the modified step Le Fort I osteotomy technique increased the NA, which may have a positive effect on breathing function. On the other hand, although TV tended to decrease, MNIV did not change after surgery as the same decreasing tendency also existed in INCV. CLINICAL RELEVANCE: Step Le Fort I advancement surgery technique usually affects nasal structures positively regarding the nasal airway.

A learning curve in 3D virtual surgical planned orthognathic surgery.

OBJECTIVES: To assess the surgical accuracy of 3D virtual surgical planned orthognathic surgery and the influence of posterior impaction and magnitude of the planned movements on a possible learning curve. MATERIALS AND METHODS: This prospective cohort study included subjects who underwent bimaxillary surgery between 2016 and 2020 at the Department of Oral and Maxillofacial Surgery of the Radboud University Medical Center, Nijmegen. 3D virtual surgical planning (VSP) was performed with CBCT data and digitalized dentition data. By using voxel-based matching with pre- and postoperative CBCT data the maxillary movements were quantified in six degrees of freedom. The primary outcome variable, surgical accuracy, was defined as the difference between the planned and achieved maxillary movement. RESULTS: Based on 124 subjects, the surgical accuracy increased annually from 2016 to 2020 in terms of vertical translations (0.82 ± 0.28 mm; p = 0.038) and yaw rotations (0.68 ± 0.22°; p = 0.028). An increase in surgical accuracy was observed when combining all six degrees of freedom (p = 0.021) and specifically between 2016 and 2020 (p = 0.004). An unfavorable learning curve was seen with posterior impaction and with a greater magnitude of movements. CONCLUSION: The present study demonstrated a significant increase in surgical accuracy annually and therefore supports the presence of a learning curve. CLINICAL RELEVANCE: Cases with planned maxillary posterior impaction and/or a great magnitude of jaw movements should be transferred from the 3D VSP with extra care to obtain a satisfactory surgical accuracy.

What are the surgical risks and 2-year stability of mandibular anterior subapical osteotomy in the treatment of dentoalveolar protrusion?

OBJECTIVE: To investigate the stability and complications of mandibular anterior subapical osteotomy (ASO) in the treatment of bimaxillary dentoalveolar protrusion by way of a retrospective study. MATERIALS AND METHODS: One hundred and twenty patients who received orthognathic surgery at a single center between 2008 and 2017 were included. Relapse was assessed by serial tracings of lateral cephalograms which were obtained pre-operatively (T1), within 6 weeks after surgery (T2) and at 2 years after surgery. The changes between T2 and T3 represented stability and were tested using the paired t test. The relationship between the extents of surgical repositioning (T2-T1) and relapse (T3-T2) was investigated using the Pearson correlation coefficient. The associations between the variables and the occurrence of relapse and complications identified the risk factors and were evaluated using the χ2 test or Fisher's exact test. When r > 0.80, clinical correlation was considered significant; and statistical significance was set at P < 0.05, while confidence interval was set at 95%. RESULTS: There was a mean uprighting of L1-MP by 12.7°. At 2 years after surgery, 96.7% of the patients experienced a mean relapse of L1-MP by 2.9°. The extent of surgical repositioning was only weakly correlated with that of relapse and no specific factor that increased the risk of relapse could be identified. The most frequent complications were blood loss requiring transfusion, wound dehiscence or infection, gingival recession, and periodontal bone loss, involving 25.8 to 43.3% of the patients. The remaining complications included tooth root damage, fixation hardware exposure or infection, lingual mucosal laceration, and tooth devitalization. There were no cases of avascular necrosis or nonunion. CONCLUSIONS: Although relapse occurred in most of the patients after 2 years, the actual extent was small (2.9°) which was not likely to be clinically significant. TRIAL REGISTRATION: HKUCTR-2964 CLINICAL RELEVANCE: Although ASO may be valuable in correcting mandibular dentoalveolar protrusion, the procedure brings with it risks and complications and should be reserved for severe deformities.

Long-term evaluation of the upper airway following mandibular setback surgery in the patients with mandibular prognathism.

OBJECTIVE: The aim of this study was to evaluate the changes in the upper airway following mandibular setback surgery. METHODS: The patients underwent mandibular setback surgery and cone-beam computed tomography scan data obtained at four time points: before surgery, immediately after surgery, short- and long-term follow-up. Upper airway geometries were segmented and extracted at each time point. Time-averaged airflow through the upper airway was evaluated at each time point. The measurements of airway volume and minimum cross-sectional areas were obtained at four time points. RESULTS: The airway volume and cross-sectional areas of airway significantly decreased immediately after surgery (p = 0.013 for airway volume and 0.016 for cross-sectional area). At short-term follow-up, the decreased airway volume and cross-sectional areas still showed statistically significant difference to original dimension (p = 0.017 for airway volume and 0.006 for cross-sectional area). At long-term follow-up, although there were no statistical significances (p = 0.859 for airway volume and 0.721 for cross-sectional area), the airway volume and cross-sectional areas had increased slightly compared to those at short-term follow-up. CONCLUSIONS: Although the airflow and dimensional parameters of the upper airway worsened following mandibular setback surgery, there was a tendency to gradually recover during long-term follow-up.

[Effect of alar base cinch suture based on anatomic landmarks on the morphology of nasolabial region in patients after orthognathic surgery].

OBJECTIVE: To study the effect of a modified alar base cinch suture (ABCS) based on nasal musculature anatomy on the three-dimensional morphology of nasolabial region in patients after Le Fort Ⅰ osteotomy. METHODS: In the study, 30 patients[11 males and 19 females, with an average age of (23.23±2.98) years]with skeletal Class Ⅲ malocclusion underwent orthognathic surgery between August, 2019 and January, 2020 to have the maxilla advanced no more than 4 mm in the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology were involved and were divided into the test and control groups based on the random number table.In the test group, the nasal musculature was identified and labeled before dissection and the ABCS was according to the label, while in the control group, the nasal musculature was directly sutured and knotted in the midline of nose without prepend labeling.All the patients underwent three-dimensional facial photos preoperatively and 6 months postoperatively by using 3dMD face system.On the three dimensional image, soft tissue landmarks of nasolabial region was identified by the same examiner.Fourteen measurements including straight distance, curve distance, angle and ratio were measured.Statistical analysis was done by using SPSS 22.0. RESULTS: There were significant differences between the two groups in cutaneous height of upper lip (P=0.023) and in nasal tip protrusion-alar width (P=0.012).The increase rate of cutaneous height of upper lip and the decrease rate of nasal tip protrusion-alar width in the control group were significantly higher than that in the test group.The alar width and alar base width of the both groups were significantly increased compared with the preoperative level (P < 0.05).The nasolabial angle in the control group was significantly higher compared with the normal value, while there was no significant difference between the test group and the normal value. CONCLUSION: Compared with the conventional suture method, this modified alar base cinch suture is more favorable for the postoperative nasal coordination and nasolabial morphology in patients who need mild to moderate maxillary advancement, and it has certain advantages in operability and objective accuracy.So it could become a modified and accurate method of alar base cinch suture and be widely applied in clinical practice.

Effectiveness Of Computed Tomography-Guided Nasotracheal Intubation Procedure On Predicting Tube Advancement Difficulty And Preventing Epistaxis: A Prospective Case-Control Study.

Objectives: To evaluate the effectiveness of computed tomography-guided nasotracheal intubation procedure in predicting tube advancement difficulty and preventing epistaxis. METHODS: The prospective study was conducted at Erciyes University Faculty of Dentistry from April 2018 to June 2019 and comprised maxillofacial surgery patients of either gender aged 18-50 years who were due to undergo bimaxillary orthognathic surgery, which was defined as American Society of Anaesthesiology grade I or II. The space where the tube was to be passed in the internal nasal valve region was measured horizontally and vertically using computed tomography. A single experienced anaesthesiologists intubated all the patients who were later divided into 'easy' group A and 'difficult' group B on the basis of the effort required to advance the tube through the nasal passage. Data was analysed using JASP version 0.14.1.0). RESULTS: Of the 60 patients, 42(70%) were females and 18(30%) were males. The overall mean age was 29.0±10.5 years and the mean body mass index value was 23.6±4.0 kg/m 2 (p>0.05). There were 28(46.6%) patients in group A, and 32(53.3%) in group B. Median distances were significantly shorter and epistaxis was significantly higher in group B compared to group A (p<0.001). The cut-off values to reveal the distance at which difficulty may be experienced while advancing the tube, determined through receiver operating characteristic analysis, were 1.09 cm for vertical and 0.39cm for horizontal distances. CONCLUSIONS: The nasotracheal intubation procedure under the guidance of computed tomography could help predict the difficulty of tube advancement, and could thus prevent epistaxis and other related nasal intubation complications. Clinical trial number: NCT05525754.

A mathematical algorithm of the facial symmetry plane: Application to mandibular deformity 3D facial data.

The three-dimensional (3D) symmetry reference plane (SRP) is the premise and basis of 3D facial symmetry analysis. Currently, most methods for extracting the SRP are based on anatomical landmarks measured manually using a digital 3D facial model. However, as different clinicians have varying definitions of landmarks, establishing common methods suitable for different types of facial asymmetry remains challenging. The present study aimed to investigate and evaluate a novel mathematical algorithm based on power function weighted Procrustes analysis (PWPA) to determine 3D facial SRPs for patients with mandibular deviation. From 30 patients with mandibular deviation, 3D facial SRPs were determined using both our PWPA algorithms (two functions) and the traditional PA algorithm (experimental groups). A reference plane, defined by experts, was considered the 'truth plane'. The 'position error' index of mirrored landmarks was created to quantitatively evaluate the difference among the PWPA SRPs and the truth plane, including overall differences and regional differences of the face (upper, middle and lower). The 'angle error' values between the SRPs and the truth plane in the experimental groups were also evaluated in this study. Statistics and measurement analyses were used to comprehensively evaluate the clinical suitability of the PWPA algorithms to construct the SRP. The average angle error values between the PWPA SRPs of the two functions and the truth plane were 1.21 ± 0.65° and 1.18 ± 0.62°, which were smaller than those between the PA SRP and the truth plane. The position error values of mirrored landmarks constructed using the PWPA algorithms for the whole face and for each facial partition were lower than those constructed using the PA algorithm. In conclusion, for patients with mandibular deviation, this novel mathematical algorithm provided a more suitable SRP for their 3D facial model, which achieved a result approaching the true effect of experts.

Surgically assisted rapid palatal expansion (SARPE): three-dimensional superimposition on cranial base.

OBJECTIVES: To evaluate dental and skeletal changes caused by surgically assisted rapid palatal expansion (SARPE) using the superimposition of three-dimensional cone-beam computed tomography (CBCT) images on the cranial base. MATERIAL AND METHODS: This is a retrospective quasi-experiment before-and-after study using a convenience sample. Twenty-four adult patients (13 male and 11 female) were evaluated before SARPE (T0), immediately after expansion (T1), and after 6 months of retention (T2). CBCT scans were superimposed on the anterior cranial base using voxel-based registration. Measurements from different reference points were used for comparisons between times. RESULTS: At T1, all teeth had significant buccal tipping. At T2, most teeth remained in the same position as at T1, except the first premolar and the first molar, whose buccal roots moved slightly. The amount of bony expansion was 65 to 70% of the amount of tooth movement. The A point and maxillary incisors moved anteriorly from T0 to T1 and T2 (p < 0.0001). Inter-nasal distance had increased significantly at T1 (p < 0.0001) and remained stable at T2 (p = 0.478). No expansion was achieved at the zygomatic arch (p = 0.114). CONCLUSION: SARPE promoted substantial buccal tipping of posterior teeth and some bone displacement; it also moved the maxilla and teeth forward and increased nasal width. CLINICAL RELEVANCE: No other clinical studies have evaluated dental and skeletal changes caused by SARPE using superimposition of 3D CBCT images on the cranial base. This study findings may help clinical dentists plan treatments using safe and reliable information.

Oral health-related quality of life before, during, and after orthodontic-orthognathic treatment: a systematic review and meta-analysis.

OBJECTIVES: The effect of combined orthodontic-orthognathic treatment was estimated, specifically the impact of pre-surgical orthodontic treatment, on oral health-related quality of life (OHRQoL). MATERIALS AND METHODS: The research question was formulated using the PICO method. The search was carried out in MEDLINE via PubMed, CINAHL, psychINFO, Embase, and Cochrane (until February 3, 2020). Inclusion criteria were patients aged ≥ 17 years who underwent combined orthodontic-surgical treatment, quality of life assessment, and study design of randomized controlled trial, controlled clinical trial, prospective cohort study, observational study, intervention study, or cross-sectional study. The ROBINS-1 tool was used to assess the risk of bias within studies. A random effects meta-analysis was conducted when appropriate. The quality of evidence was assessed using the GRADE approach. RESULTS: Six studies were analyzed. The OHIP-14 and/or OQLQ-22 questionnaires were used to measure the OHRQoL. All six studies had a serious risk of bias. Two studies (87 participants) were included in a meta-analysis showing improvement of OHRQoL when comparing before and after treatment were compared (mean 14.85 scale points, 95% confidence interval 10.36;19.35). CONCLUSIONS: Studies indicate a decrease in OHRQoL during the pre-surgical orthodontic treatment phase but improvement after orthodontic-orthognathic treatment. Data substantiating these results are limited, and the quality of evidence is low. Further research is needed to assess the impact of pre-surgical orthodontic treatment on the OHRQoL in an orthognathic trajectory. CLINICAL RELEVANCE: Patients should be well informed about the effect facial/esthetic changes may have on their OHRQoL during sequential phases of orthodontic-orthognathic treatment.

Stability of single-jaw vs two-jaw surgery following the correction of skeletal class III malocclusion: A systematic review and meta-analysis.

This review aims to compare the stability of sagittal skeletal and overjet anteroposterior correction of skeletal class III malocclusion in single-jaw and two-jaw orthognathic procedures. An unrestricted comprehensive electronic search was undertaken on Embase, Cochrane's CENTRAL, Web of Science, Medline, Scopus and LILACs databases up to October 2020. The bibliographies of relevant studies, ongoing, unpublished and grey literature were screened. Two independent reviewers performed study selection, bias assessment and data extraction; a third reviewer mediated inconsistencies. Randomized clinical trials, prospective cohort, retrospective cohort and series with a minimum of 1 year follow-up were eligible for inclusion. Additional subgroup analyses were undertaken. The generated effects were scored using the GRADE approach. Nine articles met the inclusion criteria and eight studies were subsequently analysed quantitatively. No significant difference in sagittal stability at the ANB angle, A-point or B-point on a short-term was detected. However, a statistically significant difference, indicating a greater short-term relapse in overjet with mandibular setbacks alone, was found (MD: -0.40 mm; 95% CI -0.77 to -0.04; I2 : 0%; P = .03). Long-term follow-up (≥5 years) revealed a statistically non-significant difference in stability of sagittal skeletal and overjet corrections. Within the limitations of this review, both procedures seem to offer comparable skeletal and overjet stability outcomes; however, further high-quality research is required to confirm these findings.

A simple and free software-based inferior alveolar nerve protector surgical guide in bilateral sagittal split osteotomy.

OBJECTIVES: This technical note introduces a novel concept of a alveolar inferior nerve protector guide during orthognathic surgery based on a free-software creation and printing. TECHNICAL NOTE: Orthognathic surgery using Virtual Surgical Planning software like Dolphin Imaging ® v 11.9 facilitated a bimaxillary procedure with mandible advancement and occlusal plane correction, later followed by 3D printing of splints. The process involved importing a composite skull with osteotomies into Blender ® software, where solids were added and edited to match Dolphin's osteotomies, ensuring bone contact without distortion. The guide creation was performed adhering to bilateral sagittal split osteotomy principles, maintaining precision, resulting in preserved inferior alveolar nerve and faster operation times compared to non-guided procedures, as demonstrated by postoperative CT scans. CONCLUSIONS: Integrating advanced tools like Blender software into maxillofacial surgery represents a significant advancement. Despite challenges like the absence of specific manuals for this purpose in Blender, using such software offers innovative and cost-effective solutions. Developing user-friendly resources tailored to surgical applications such as a protector guide within Blender can enhance its usability and improve surgical outcomes and patient care, leading to groundbreaking advancements in maxillofacial surgery.

A case series on a new reference in mandibular angles harmonization: the Frontozygomatic-Infraorbital Line (FZ-IOL).

the aim of this paper, is to propose a new reference line: the Frontozygomatic-Infraorbital Line (FZ-IOL). This reference line can guide the surgical team planning mandibular angle harmonization, based on the patient's skeletal proportion. The Frontozygomatic-Infraorbital Line has been adopted for symmetrization surgery, masculinization surgery, and in unsatisfactory results of previous orthognathic surgery. From March 2021 to December 2022, 3 patients were treated for severe facial asymmetry affecting mainly the lower third of the face. All cases were planned with the reference FZ-IOL. Patients were treated in the same center, at the Orthognathic Surgery Department of the Instituto Portugues da Face, Lisbon, Portugal. The Frontozygomatic-Infraorbital Line is designed virtually using software to reconstruct a 3D image from a digital imaging and communications in medicine (DICOM) file obtained from a cone beam computer tomography (CBCT). , connecting the two orbital rims. Then, a vertical line, the frontozygomatic line perpendicular to the IOL and passing through the outmost lateral portion of the frontozygomatic suture is drawn. The proposed line demonstrated how establishing appropriate reference lines is crucial for the success of the surgery. The selection of reference lines should be based on the patient's anatomy, the symmetrization process's complexity, and the surgery's desired outcome. The Frontozygomatic-Infraorbital Line represents an adequate reference line for managing mandibular angle lateral projection, improving lower third of the face symmetrization.

Cephalometric Screening Assessment for Superior Airway Space Narrowing-Added Value of Three-Dimensional Imaging.

Background: Assessing the morphology of the superior airway space is a crucial diagnostic step in the treatment planning of patients with obstructive sleep apnea syndrome (OSAS) or prior to orthognathic surgery. The aim of this study is to evaluate the necessary scope of a two-dimensional cephalometric assessment and the necessity of three-dimensional imaging in the identification of superior airway space narrowing (SASN). Methods: The computed tomography studies of 100 non-obese, non-OSAS patients were evaluated and analyzed retrospectively. Multiplanar reconstructions were created and underwent cephalometric evaluation. The three-dimensional superior airway morphology was segmented and measured for the minimal cross-sectional area (Amin) and volume (V0). Patients were grouped according to Amin < 80 mm2 and V0 < 12 cm3. Cephalometric parameters (CPs) were analyzed according to Amin and V0 with an unpaired t-test, Pearson correlation, and ROC-curve analysis. Results: The CPs regarding sagittal airway space dimensions (IPAS, MPAS, SPAS) and mandibular body length (GoGn) show the strongest correlation to the three-dimensional minimal cross-sectional area (Amin). The ROC-curve analysis classifying for SASN led to an AUC of 0.86 for IPAS, 0.87 for MPAS, 0.88 for SPAS, and 0.63 for GoGn. Three-dimensional imaging may further improve the diagnostic accuracy in the identification of SASN for IPAS below 13.5 mm, MPAS below 10.2 mm, SPAS below 12.5 mm, and GoGn below 90.2 mm. Conclusions: Two-dimensional cephalometric sagittal airway space diameters and mandibular body length are useful initial screening parameters in the identification of superior airway space narrowing. Nevertheless, as the correlation of two-dimensional cephalometric parameters with three-dimensional upper airway space narrowing is varying and highly dependent on acquisition circumstances, indications for three-dimensional imaging, if possible, in the supine position to evaluate upper airway space morphology should be provided generously, especially in patients with low but normal airway space parameters in two-dimensional cephalometry.

The Accuracy of Three-Dimensional Soft Tissue Simulation in Orthognathic Surgery-A Systematic Review.

Three-dimensional soft tissue simulation has become a popular tool in the process of virtual orthognathic surgery planning and patient-surgeon communication. To apply 3D soft tissue simulation software in routine clinical practice, both qualitative and quantitative validation of its accuracy are required. The objective of this study was to systematically review the literature on the accuracy of 3D soft tissue simulation in orthognathic surgery. The Web of Science, PubMed, Cochrane, and Embase databases were consulted for the literature search. The systematic review (SR) was conducted according to the PRISMA statement, and 40 articles fulfilled the inclusion and exclusion criteria. The Quadas-2 tool was used for the risk of bias assessment for selected studies. A mean error varying from 0.27 mm to 2.9 mm for 3D soft tissue simulations for the whole face was reported. In the studies evaluating 3D soft tissue simulation accuracy after a Le Fort I osteotomy only, the upper lip and paranasal regions were reported to have the largest error, while after an isolated bilateral sagittal split osteotomy, the largest error was reported for the lower lip and chin regions. In the studies evaluating simulation after bimaxillary osteotomy with or without genioplasty, the highest inaccuracy was reported at the level of the lips, predominantly the lower lip, chin, and, sometimes, the paranasal regions. Due to the variability in the study designs and analysis methods, a direct comparison was not possible. Therefore, based on the results of this SR, guidelines to systematize the workflow for evaluating the accuracy of 3D soft tissue simulations in orthognathic surgery in future studies are proposed.

Pre- and Post-Operative Cone Beam Computed Tomography Assessment of the Temporomandibular Joint in Patients with Orthognathic Surgery.

This study aimed to compare the pre- and post-operative temporomandibular joint (TMJ) condylar position in dentofacial deformity (DFD) patients who had orthognathic surgeries using cone beam computed tomography (CBCT). A retrospective study evaluating the pre- and post-operative CBCT for 79 DFD patients (equivalent to 158 TMJs) (mean age = 26.62 ± 9.5 years) with a bilateral sagittal split osteotomy with or without Le Fort I surgeries (n = 29 Class II DFD, n = 50 Class III DFD) was performed. This included the compartmental measurement of TMJ spaces, in addition to the measurement of intercondylar distances and angles. Condylar position centricity was assessed using the Pullinger and Hollender formula. Clinical data were analysed for DFD class, the type of surgery and post-operative CBCT timing. Pre- and post-operative measurements were compared statistically using a paired t-test, Wilcoxon signed-rank test, and Stuart-Maxwell test. TMJ condyles tended to relocate post-operatively in a posterosuperior position with internal rotation in Class II DFD and a superior position with internal rotation in Class III DFD. However, the overall changes were within <0.5 mm translation and <4° rotation and the number of concentrically positioned condyles (according to the Pullinger and Hollender formula) did not change significantly. Orthognathic surgery is associated with minor post-operative translational and rotational condylar positional changes in Class II and III DFDs.