Soft tissue response and facial symmetry after orthognathic surgery

ObjectiveIn orthognathic surgery aesthetic issues and facial symmetry are vital parameters in surgical planning. Aim of this investigation was to document and analyze the results of orthognathic surgery on the base of a three-dimensional photogrammetric assessment, to assess the soft tissue response related to the skeletal shift and the alterations in facial symmetry after orthognathic surgery.Patients and methodsIn this prospective clinical trial from January 2010 to June 2011, 104 patients were examined who underwent orthognathic surgery due to mono- or bimaxillary dysgnathia. The standardized measurements, based on optical 3D face scans, took place one day before orthognathic surgery (T1) and one day before removal of osteosynthesis material (T2).ResultsSoft tissue changes after procedures involving the mandible showed significant positive correlations and strong soft tissue response (p < 0.05). The midfacial soft tissue response after maxillary advancement was only of minor extent (p > 0.05). The facial surfaces became more symmetric and harmonic with the exception of surgical maxillary expansion, but improvement of facial symmetry revealed no statistical significance.ConclusionSoft tissue response after orthognathic surgery and symmetry are only partially predictable, especially in the maxillary and midfacial region. Computer programs predicting soft tissue changes are not currently safely reliable and should not be used or with caution to demonstrate a patient potential outcome of surgery.     

Evaluation of soft tissue prediction accuracy for orthognathic surgery with skeletal class III malocclusion using maxillofacial regional aesthetic units

Objectives

This study aimed to evaluate the soft tissue prediction accuracy of patients undergoing orthognathic surgery to correct skeletal class III malocclusion using maxillofacial regional aesthetic units.

Materials and methods

Pre- and postoperative cone-beam computed tomography (CBCT) and 3D facial scans were taken for 58 patients who had undergone orthognathic surgery. The preoperative 3D facial scan was integrated with the preoperative CBCT using ProPlan CMF software. The software simulated the surgery and generated postoperative soft tissue prediction. The simulated 3D facial scan was then compared with the actual 3D facial scan obtained at least 6 months after the surgery by the maxillofacial regional aesthetic units and the facial soft tissue landmark points.

Results

The anatomical regions of the upper lip, lower lip, chin, right external buccal and left external buccal prediction were above 2.0 mm. As for the soft tissue landmarks, at chl, chr, ls, stm and li, the position of predicted scan was higher than that of the actual postoperative scan.

Conclusions

The accuracy of 3D soft tissue predictions using ProPlan CMF software in Skeletal III patients was clinically satisfactory according to maxillofacial regional aesthetic units combined with facial soft tissue landmark points. However, the accuracy of prediction still needed improvement in some areas.

Clinical relevance

The accuracy of soft tissue prediction can be analyzed more clearly through maxillofacial regional aesthetic units so that clinicians have a deeper understanding of the use of the software to predict soft tissue change after orthognathic surgery.

     

Sequential changes of postoperative condylar position in patients with facial asymmetry

Objective:To evaluate sequential images of the condylar position in relation to the glenoid fossa after orthognathic surgery in patients with facial asymmetry using cone beam computed tomography.Materials and Methods:A total of 20 adult patients (11 men and 9 women; mean age, 22.1 ± 4.02 years) with facial asymmetry who underwent sagittal split ramus osteotomy with rigid fixation were involved. Cone beam computed tomography scans were obtained before treatment (T0), 1 month before the surgery (T1), and 1 day (T2), 3 months (T3), 6 months (T4), and 12 months (T5) after the surgery. The condyle position was evaluated.Results:At 1 day after surgery (T2), the condylar position on both sides significantly changed posteriorly, inferiorly, and laterally, but no significant difference was observed between the nonaffected and affected sides. The condyle on the nonaffected side had a tendency to recover its preoperative position at 3 months after surgery (T3) and inclined slightly laterally up to 1 year after the surgery (T5). The condyle on the affected side returned more closely to the glenoid fossa than to its pretreatment position at 3 months after surgery (T3). Thereafter, it showed a more backward and downward position (T5).Conclusions:The overall condylar position after an orthognathic surgery in patients with facial asymmetry was relatively stable at 1 year after surgery. However, the condyle on the affected side during the first 3 months after surgery should be carefully monitored for surgical stability.     

The relationship between the changes in three-dimensional facial morphology and mandibular movement after orthognathic surgery

PurposeThe purpose of this study was to investigate the relationship between changes in three-dimensional (3D) facial morphology and mandibular movement after orthognathic surgery. We hypothesized that facial morphology changes after orthognathic surgery exert effects on 3D mandibular movement.Materials and methodsWe conducted a prospective follow-up study of patients who had undergone orthognathic surgical procedures. Three-dimensional facial morphological values were measured from facial CT images before and three months after orthognathic surgery. Three-dimensional maximum mandibular opening (MMO) values of four points (bilateral condylions, infradentale, and pogonion) were also measured using a mandibular movement tracking and simulation system. The predictor variables were changes in morphological parameters divided into two groups (deviated side (DS) or contralateral side (CS) groups), and the outcome variables were changes in the MMO at four points.ResultsWe evaluated 21 subjects who had undergone orthognathic surgical procedures. Alterations in the TFH (total facial height), LFH (lower facial height), CS MBL (mandibular body length), and DS RL (ramus length) were negatively correlated with changes in bilateral condylar movement. The UFH, DS MBL and CS ML (mandibular length) showed correlations with infradentale movement. The CS ML, DS ML, MBL, UFH, and SNB were correlated with pogonion movement.ConclusionThe height of the face is most likely to affect post-operative mandibular movement, and is negatively correlated with movement changes in the condyles, infradentale and pogonion. The changes in CS morphological parameters are more correlated with mandibular movement changes than the DS. The changes in CS MBL and bilateral RL were negatively correlated with condylar movement changes, while the bilateral MBL and CS ML were positively correlated with changes in infradentale and pogonion.     

Long-term outcomes of bimaxillary surgery for treatment of asymmetric skeletal class III deformity using surgery-first approach

Objectives

Although several studies have reported the advantages of the surgery-first approach for orthognathic correction of Class III deformity, there are few reports of the success of this approach for patients with facial asymmetry. Therefore, the purpose of this study was to evaluate the outcome of bimaxillary surgery for asymmetric skeletal Class III deformity using a surgery-first approach.

Materials and methods

Sixty-five patients who consecutively underwent at least a combined Le Fort I and a bilateral sagittal split osteotomy for asymmetric skeletal Class III deformity were identified in the authors’ patient database. Standardized frontal photographs were used to measure the change in midface, intercommissural line, chin from midface, and chin deviation angles as well as upper, middle, and lower contour deviation angles. The facial midline symmetry index, facial contour symmetry index, and overall facial symmetry index were also calculated. Self-reported questionnaires regarding overall appearance and satisfaction with facial areas were administered at least 1 year post-surgery.

Results

Forty-six patients had genioplasty. There was a statistically significant improvement in the deviation angles measured and the facial midline, facial contour, and overall facial symmetry index. Self-reported questionnaires, completed at least 1 year post-surgery, showed that patient satisfaction was high.

Conclusions

These findings demonstrate that the surgical-orthodontic treatment with surgery-first approach can successfully maintain or improve facial symmetry.

Clinical relevance

The surgery-first approach for improving facial asymmetry using the guidelines described for setups of the models is a feasible alternative to the classic orthodontic-first approach for bimaxillary orthognathic surgery.

     

A new method for the 3D measurement of postoperative swelling following orthognathic surgery

OBJECTIVE: To describe a new method for measuring facial swelling following orthognathic surgery using a 3D laser-scanning device. DESIGN: Prospective clinical trial. Setting and Sample Population -- University Dental Hospital, Wales College of Medicine, Biology Life and Health Sciences. Three subjects requiring bi-maxillary orthognathic surgery were recruited for the study. EXPERIMENTAL VARIABLES: Laser-scanned images of the subjects were obtained under a reproducible and controlled environment with two Minolta Vivid 900 (Osaka, Japan) optical laser-scanning devices assembled as a stereo-pair. A set of left and right scanned images was taken for each subject and each scan took an average of 2.5 s. 3D laser scans were recorded over six time periods (T1 -- pre-surgical scan, postoperatively: T2 -- 1 day, T3 -- 1 week, T4 -- 1 month, T5 -- 3 months and T6 -- 6 months). OUTCOME MEASURE: Facial scans from different time periods were overlaid onto the baseline (T6) facial scan to determine the reduction and changes in swelling following orthognathic surgery. RESULTS: The results showed that swelling could be accurately quantified following surgery. Furthermore, there was a significant reduction in the amount of swelling 1 month postoperatively. Furthermore, the facial morphology returned to approximately 90% of the baseline facial scan at 3 months. CONCLUSION: The 3D laser-scanning device and the method described was a reliable and accurate measure of facial swelling following surgery.     

Quality of life several years after orthodontic-surgical treatment with bilateral sagittal split osteotomy

Abstract

Objective: To analyse oral health related quality of life (OHRQoL) several years after orthognathic treatment in patients who had Class II malocclusion with retrognathic mandible.

Material and methods: The initial study cohort comprised 151 patients with orthognathic treatment in 2007–2011. Of them, 77 patients (Group 1, mean age 41?years, range 19–71?years, 71% women) were clinically examined 6?years (range 4–8?years) after bilateral sagittal split osteotomy (BSSO). Group 2 included 24 former patients (mean 48?years, range 25–79?years, 50% women) who were willing to participate in a structured telephone interview. Group 3 consisted of 22 prospective patients (mean 35?years, range 18–56?years, 86% women) with a recent orthognathic treatment plan and awaiting treatment. QoL was assessed using two questionnaires, OHIP-14 and OQLQ.

Results: Based on responses, patients who had received orthognathic treatment (Groups 1 and 2) had better QoL than those awaiting treatment (Group 3).

Conclusion: Conventional orthognathic treatment, including mandibular advancement with BSSO, seems to have a positive long-term effect on patients’ QoL. More long-term follow-up studies are needed to assess the real impact of treatment on patients’ lives in the long run.     

Impact of orthognathic surgery on the prevalence of dehiscence in Class II and Class III surgical-orthodontic patients:: A cone beam computed tomographic study

ObjectivesThe objectives were to evaluate and compare the presence of bone dehiscence before and after orthognathic surgery.Materials and MethodsIn this retrospective study, 90 cone-beam computed tomography (CBCT) scans from 45 patients were evaluated. Class II (n = 23) and Class III (n = 22) orthodontic patients who were being prepared for orthognathic surgery were measured. CBCT scans were obtained about 30 days prior to (T0) and 6 months after (T1) double jaw orthognathic surgery. The distance between the cemento-enamel junction (CEJ) and the alveolar bone crest was assessed at the buccal and lingual surfaces of all teeth, on both sides and arches, except for the second premolars and the second and third molars. A total of 1332 sites were measured for Class II (644) and Class III (688) patients. The software used was OsiriX (version 3.3 32-bit). Data were compared with Wilcoxon and McNemar tests at the 5% level.ResultsBone dehiscence before surgery was present in 26% and 15% of the Class II and III groups, respectively. The presence of dehiscence increased to 31% in the Class II and 20% in the Class III patients after surgery (P < .05).ConclusionsThe prevalence of dehiscence increased slightly in Class II and Class III surgical-orthodontic patients after orthognathic surgery. Temporary vascular supply reduction and oral hygiene difficulties may explain these results; however, more studies are needed.     

Different Modalities to Record and Transfer Natural Head Position to Virtual Planning in Orthognathic Surgery: Case Reports of Asymmetric Patients

AimTo describe different modalities to record and transfer natural head position (NHP) to 3D facial imaging by using the virtual surgical planning software in three facial asymmetry patients.Case ReportsThree patients with facial asymmetries (A, B, and C) were evaluated by means of dental and facial analysis, photographs, cone-beam computed tomography (CBCT) and digitized dental arches. Before starting the VSP workflow with Dolphin Imaging, NHP was recorded by three modalities and transferred to three-dimensional (3D) facial images as follows: (a) facial photographs taken with digital camera and the estimated NHP was transferred to 3D images by comparing lines and planes from both images; (b) cross-line level laser was used to place radiopaque markers on the face skin for recording the estimated NHP, which was transferred to 3D images by alignment of planes and markers in the software; and (c) photographs of the face were processed to generate facial surface mesh by using the Agisoft PhotoScan software, which maintained the same position of the estimated NHP in 3D for aligning the images of the soft tissue with the facial surface mesh by using superimposition. All the three patients underwent bi-maxillary orthognathic surgery.ConclusionThere are different modalities using simple and available technologies in the clinical routine, but whose reproducibility, reliability and validation could not be assessed nor compared to each other. There was no trend for better predictability, feasibility and efficiency because the postoperative outcomes were adequate regarding the patients’ satisfaction and facial symmetry.     

Self-Perception of Dentofacial Attractiveness among Patients Requiring Orthognathic Surgery

Objective:To test the hypothesis that the self-perception of dental and facial attractiveness among patients requiring orthognathic surgery is no different from that of control patients.Materials and Methods:Happiness with dental and facial appearance was assessed using questionnaires completed by 162 patients who required orthognathic treatment and 157 control subjects. Visual analog scale, binary, and open response data were collected. Analysis was carried out using a general linear model, logistic regression, and chi-square tests.Results:Orthognathic patients were less happy with their dental appearance than were controls. Class II patients and women had lower happiness scores for their dental appearance. Among orthognathic patients, the “shape” and “prominence” of their teeth were the most frequent causes of concern. Older subjects, women, and orthognathic patients were less happy with their facial appearance. Class III orthognathic patients, older subjects, and women were more likely to have looked at their own face in profile. A greater proportion of Class II subjects than Class III subjects wished to change their appearance.Conclusions:The hypothesis is rejected. The findings indicate that women and patients requiring orthognathic surgery had lower levels of happiness with their dentofacial appearance. Although Class II patients exhibited the lowest levels of happiness with their dental appearance, there was some evidence that concerns and awareness about their facial profile were more pronounced among the Class III patients.     

Evaluation of maxillary sinus volume and dimensions in different vertical face growth patterns: a study of cone-beam computed tomography

Objective: This study aimed to compare sinus volume and dimensions in patients with high-, low-, and normal-angle vertical growth patterns using cone-beam computed tomography (CBCT).

Materials and methods: According to skeletal vertical face growth patterns, 60 adults (31 female, 29 male, average age: 29.90?±?10.91 years) were divided into three groups equally: high-angle, low-angle, and normal-angle groups. Cephalometric tracings were obtained from CBCT images and SN-GoGn (angle between Sella–Nasion line and Gonion–Gnathion line) cephalometric angular measurements used for the classification of skeletal vertical pattern evaluations. Morphological and dimensional changes in the maxillary sinuses were evaluated on CBCT images. Data were analyzed using the one-way ANOVA, Kruskall–Wallis, and Mann–Whitney U statistical tests.

Results: There were no statistically significant differences among the groups in terms of age (p?>?.05). The low-angle vertical growth pattern group showed significantly better results than the high-angle group in the right maxillary sinus length parameter (p?Conclusion: According to the results, the high-angle subjects showed statistically lower values in terms of maxillary sinus length and width than the low-angle subjects. There were no effects of vertical face development on right and left maxillary sinus volumes. The results of this study may be useful in maxillary sinus evaluation when planning for orthognathic surgery and orthodontic mini screw application in various vertical face patterns.     

Patient's satisfaction with facial appearance and psycho-social wellness after orthognathic surgery among Hong Kong Chinese using the FACE-Q

PurposeTo assess and compare the changes in satisfaction with facial appearance and psycho-social well-being in dento-skeletal class II and III patients after orthognathic surgery with the FACE-Q among Hong Kong Chinese.MethodsThe questionnaires for thirteen orthognathic-relevant FACE-Q scales, translated into Cantonese and validated, were administered to Hong Kong Chinese patients before and after orthognathic surgery in the short- and long-term, respectively. The assessed scales were categorized into four main domains: satisfaction with facial appearance, quality of life, patient's experience of care, and adverse effects.ResultsGenerally, highly significant (p < 0.001) improved FACE-Q scores were found in the long-term in the scales investigating the satisfaction with overall facial appearance, lower face and jawline, and chin. Although dento-skeletal class III patients demonstrated significantly improved satisfaction with their post-surgical nostril appearance (p = 0.003), this was not evident in dento-skeletal class II patients (p = 0.231). Nonetheless, both class II and class III subjects have also revealed significantly improved psychological well-being (0.003; <0.001) and social function (0.001; <0.001) in the long-term. Age was not found to be correlated with all scales for satisfaction of facial appearance.ConclusionPreviously validated Face-Q scales are valuable instruments to measure clinical outcomes, psychological well-being and social function in Cantonese speaking patients. Both Class II and Class III patients showed significantly improved satisfaction with facial appearance, psychological well-being and social function after orthognathic surgery regardless of skeletal pattern and gender, confirming findings in other ethnicities.     

Masseter muscle changes following orthognathic surgery: A long-term three-dimensional computed tomography follow-up

Objective:To evaluate the long-term changes of masseter muscle morphology in skeletal Class III patients with facial asymmetry following two-jaw orthognathic surgery (Le Fort I osteotomy + intraoral vertical ramus osteotomy).Materials and Methods:Using computed tomography (CT), a longitudinal study was conducted on 17 skeletal Class III patients with facial asymmetry. Measurements from the reconstructed three-dimensional (3D) CT images were compared from T1 (before surgery), T2 (1 year after surgery), and T3 (4 years after surgery). The maximum cross-sectional area (CSA), orientation, thickness, and width of the masseter muscle were measured on both the deviated and nondeviated sides. The control group included 17 volunteers with skeletal and dental Class I relationships without dentofacial deformities.Results:At T1, there were no significant differences in CSA, thickness, or width of masseter muscle between the deviated and nondeviated sides. Masseter muscle orientation was significantly more vertical on the nondeviated side than on the deviated side at T1 (P < .01); no significant bilateral differences were noted at T2 and T3. At T1, masseter muscle measurements were significantly lower than controls (P < .01). During T1–T3, a significant increase was noted in CSA, thickness, and width (P < .01) of masseter muscle. At T3, no significant difference was noted between the study and control groups.Conclusion:After surgery, the masseter muscle measurements of skeletal Class III asymmetry patients showed no significant differences compared with the control group within the 4-year follow-up period, indicating adaptation to the new skeletal environments and increased functional demand.     

Long-term follow-up of intersegmental displacement after orthognathic surgery using cone-beam computed tomographic superimposition

ObjectivesTo evaluate intersegmental displacement during long-term follow-up after bilateral sagittal split osteotomy (BSSO) by mandibular body area superimposition.Materials and MethodsCone-beam computed tomography (CBCT) images of 23 patients ages 18−37 years with class III malocclusion before orthognathic surgery were obtained. A three-dimensional (3D) CBCT examination was performed at four stages: surgery (T0), 6 months after surgery (T1), 1 year after surgery (T2), and long-term follow-up (6.1 ± 2.1 years, T3). The CBCT datasets were superimposed on the symphyseal area and the lower part of the distal segment of the mandible between T0 and the other time points (T1, T2, and T3). The reference points (both condyle, coronoid, and sigmoid) were estimated by the CBCT analyzed program.ResultsThe coronoid, condylion, and sigmoid showed changes within 6 months after surgery, but there was no significant change in the intersegmental displacement between 6 months and 6 years after surgery. The distances between the left and right coronoid, condylion, and sigmoid from T0 to T3 were noted.ConclusionsThe change in intersegmental displacement between T0 and T3 affecting relapse after orthognathic surgery was not significantly different. This suggests that the mandible itself may have a stable morphology during the follow-up period.     

Treatment measures of hemimandibular hyperplasia and associated facial deformities

This study aims to show our institute’s experience in the treatment of HH and its associated facial deformities in adults and growing adolescents and to investigate condylar remodeling and volumetric changes and long-term stability of orthognathic surgery in adults.The study included consecutive patients with clinical and radiological features of HH who underwent high condylectomy with or without simultaneous orthognathic surgery from 2013 to 2018. The clinical outcomes were assessed based on functional activities, TMJ pain, and recurrence. Postoperative 3D condylar remodeling and orthognathic stability were evaluated with the use of ITK-Snap and 3D Slicer.Thirteen patients (8 females and 5 males) with a mean age of 26.3 ± 5.79 years (range; 13–34 years) were included with facial asymmetry as the chief complaint. The patients were followed up for a minimum of 12 months and a maximum of 4 years (mean; 16.85 ± 10.04). There were no postoperative complications, and all patients achieved a satisfactory functional and aesthetic outcome using a one-stage surgical procedure. There was no incidence of recurrence or further asymmetries, with long-term stability at the selected points showing a mean difference of less than ±1 mm. The affected condylar volume was significantly reduced following high condylectomy, with mean changes between T1 and T2 of ?144. 80 mm³ (p = .012). However, the contralateral condylar volume remained stable, with a mean change of 2.54 mm³ (p = .881).One-stage high condylectomy and orthognathic surgery is a viable measure for the treatment of HH and associated deformities in adults. High condylectomy in early adolescence could result in termination of the disease, and aesthetic improvement with further constant orthodontist-surgeon follow-up is required.     

Effect of post–orthognathic surgery condylar axis changes on condylar morphology as determined by 3-dimensional surface reconstruction

Objective: To evaluate the effect of postoperative condylar axis changes on mandibular condylar remodeling by comparing the condylar head in three-dimensional (3D) surface reconstructions before and after surgery in skeletal Class III deformities (one-jaw [mandibular setback] or two-jaw surgery), and also to determine the relationship between condylar inward rotation and condylar surface remodeling after orthognathic surgery.Materials and Methods:A retrospective analysis was conducted of 30 patients with skeletal Class III deformities who had received orthognathic surgery. Group 1 underwent one-jaw surgery (10 men, five women, age 22.4 ± 3.3 years), and group 2 underwent two-jaw surgery (10 men, five women, age 22.3 ± 2.2 years). Sixty condyles were reconstructed and superimposed pre- and postoperatively to compare the changes of condylar surfaces. The relation between the condylar axis change and the surface change using the Pearson correlation were investigated from the 3D image software.Results:Condylar surface changes before and after the surgery were significant. The postoperative inward rotation of the condyles was correlated with the average absolute deviation of the condyles, regardless of the surgery type (one- or 2-jaw surgery; r  =  .70, P < .05).Conclusion:After orthognathic surgery, condylar surface changes occurred, and condylar inward rotation was closely related to changes of condylar surface.     

Long-term skeletal and profile stability after surgical-orthodontic treatment of Class II and Class III malocclusion

ObjectiveThe purpose of this perspective research was to study the long-term stability of skeletal, dentoalveolar and soft tissue after orthognathic surgery in subjects presenting with Class II and Class III malocclusions.MethodsThe available digitized cephalometric radiographs, including pretreatment (t₀), presurgery (t₁), a minimum of 12 months postsurgery (t₂) and at least 3 years after the orthosurgery treatment (t₃) were taken between 1998 and 2010. In Group 1 mandibular advancement and in Group 2 mandibular advancement and maxillary impaction surgery were performed for correction of Class II. In Group 3 maxillary advancement and in Group 4 surgical maxillary advancement with mandibular setback, for correction of Class III.ResultsIn all the phases mandibular length was shorter in Group 1, and the inferior third of the face was longer in Group 2. Before the surgery there was greater maxillary deficiency in Group 3 than Group 4 and mandibular length was longer in Group 4.ConclusionIn Groups 1 and 2, at retention phase, relapse occurred due to the increase in mandibular plane, whereas the surgeries performed in Groups 3 and 4 remained stable.     

Lower face cephalometry based on quadrilateral analysis with cone-beam computed tomography: a clinical pilot study

Objective

As most orthognathic surgeries focus on the lower face, the aim of this study was to transfer previously developed two-dimensional cephalometry—which is useful for surgeons in the orthognathic surgery of the lower face—to three-dimensional (3D) cephalometry by using cone-beam computed tomography (CBCT). We selected the quadrilateral lower face analysis developed by the surgeon Di Paolo, who focused only for the lower face and mentioned that data in millimeters are more easy to use than angles for surgeons. Additionally, we wanted to create a 3D lower face analysis approach based on quadrilateral analysis and establish a reference table for surgical planning.

Study design

Three investigators assigned 16 landmarks on CBCT images from 30 patients with normocclusion. Intra-class correlation coefficients (ICCs) and standard deviations (SDs) were calculated according to each landmark. The maxillary and mandibular lengths and widths and the anterior and posterior lower facial heights (ALFH and PLFH) are presented as means and SDs. The asymmetry of the face was calculated with paired t test, and the coherence of the lower face was assessed with correlation coefficients (r) and regression models.

Results

The ICCs were ≥0.90, and the SDs of the landmarks were lower than 1.00 mm, except for the J-point, which was located at the junction of the anterior border of the ramus and the corpus of the mandible. The SDs of linear measurements were 3.06–5.20 mm, and there was no significant facial asymmetry. The r among the structures was greater than 0.3 in 13 of 15 assessments. Based on these values, we could establish a floating norm of the lower face using the following five regressions: one linear regression for the mandibular length, two quadratic models for the ALFH and PLFH, and two multivariate regressions for the posterior widths of the maxillae and mandible.

Conclusion

The adaptation of quadrilateral analysis can provide accurate 3D characterization of the morphology of the lower face and the floating norm based on millimeter values, which is practical for surgeons. As the 3D extension of quadrilateral analysis could provide references of the lower face, which might be an accurate 3D approach for presurgical planning, the further investigation in bigger sample would be relevant in the practice.

     

Changes in the facial soft-tissue profile after mandibular orthognathic surgery

Objectives

To investigate the correlation between soft- and hard-tissue changes after mandibular orthognathic surgery, to generate precise prognostic values for the esthetic treatment outcome of the facial profile.

Material and Methods

In this retrospective study, sagittal changes in the facial soft tissue profile in relation to surgical changes in hard structures after mandibular osteotomy were examined. The sample population included 144 reported adult patients aged 17–50 years who had received combined mandibular orthognathic surgery and orthodontic treatment at the Department of Orthodontics, Ludwig-Maximilians University of Munich, Germany. Both mandibular advancement and mandibular setback cases in monognathic and bignathic osteotomy procedures were included. All subjects had undergone rigid fixation. A cephalometric analysis of presurgical and postsurgical cephalograms was performed, and the correlations between hard-tissue and soft-tissue change ratios were evaluated using a bivariate linear regression analysis.

Results

The lower lip, represented by the landmark Labrale inferius (Li), followed the lower incisor (Ii) by 77%. The soft-tissue B-point (B’) followed the B-point (B) by 97% and the soft-tissue Pogonion (Pg’) followed the Pogonion (Pg) by 97% in a linear correlation.

Conclusion

The scatterplots show a distinct linear correlation and no significant difference in the direction of the movement. A wider spread for the lower lip (Li/Ii) indicates a lower predictability of the expected lip position, whereas a narrow spread of the chin values (B’/B and the Pg’/Pg) reveals a very good predictability of the postoperative chin position.

Clinical relevance

This study contributes valid data for the soft-tissue profile prediction in orthognathic surgery.