Lip line changes in Class III facial asymmetry patients after orthodontic camouflage treatment, one-jaw surgery, and two-jaw surgery: A preliminary study

Three-dimensional evaluation of maxillofacial symmetry improvement following orthognathic surgery in patients with asymmetrical jaw deformities

PURPOSE

The aim of this study was to clarify the three-dimensional changes in maxillofacial morphology following orthognathic surgery using 3D-CT in patients with asymmetrical jaw deformities.

METHODS

The subjects were 30 patients with asymmetrical jaw deformities. Three-dimensional images taken preoperatively and 6 months postoperatively were re-aligned using image processing software with the horizontal plane, coronal plane, and midsagittal plane as reference axes. Thirty-nine measurements including 28 distances, nine angles, and two volumes were recorded, and differences between preoperative and postoperative measurements and percentage differences between paired measurements on the deviated and unevolved sides were calculated.

RESULTS

Translational and rotational movements of the maxillary dentition and mandibular body and the mandibular ramus internally rotating contributed to improved symmetry of the maxillofacial morphology, but the degree and proportion of these changes varied from case to case and mild asymmetry remained even after surgery.

CONCLUSIONS

3D-CT analysis of maxillofacial morphology is essential to accurately evaluate the asymmetry of hard and soft tissue morphology in the maxillofacial region and the degree of improvement after orthognathic surgery, and the tooth movement during preoperative orthodontic treatment should be determined taking into account the movement of the upper and lower jaws during orthognathic surgery.

Does facial growth pattern affect the perception of lower facial asymmetry?

OBJECTIVES

To investigate the influence of vertical facial type on esthetic perception of lower facial asymmetry as evaluated by orthodontists, dentists, and laypeople.

MATERIALS AND METHODS

Three adult females were selected with normal growth patterns (NGP), vertical growth patterns (VGP), and horizontal growth patterns (HGP). Frontal photographs were made symmetric and digitally altered, rotating the lower facial third clockwise, ranging from 0° to 6° in 1° increments. A web-based survey was designed with 24 images (eight images for each model) in random order. Each image was rated using a scale ranging from 0 (unattractive) to 10 (the most attractive) by 75 orthodontists, 73 dentists, and 78 laypeople. Kruskal-Wallis test was used to determine whether differences among groups were significant. Pairwise comparisons were made with Mann-Whitney U test. The significance level was set at P = .05.

RESULTS

In NGP, orthodontists and dentists could recognize slighter deviations (2°), while deviations in VGP and HGP under 3° were not recognized by all groups. Severe deviations (≥4°) were distinguished better in HGP by orthodontists and laypeople. In VGP and NGP, there was no significant difference over 4°.

CONCLUSIONS

Growth pattern has a significant influence on perception of lower facial asymmetry. Less severe asymmetry can be detected better in NGP. In severe degrees, increments of asymmetry can be perceived more in HGP by orthodontists and laypeople.

Three-dimensional assessment of facial asymmetry in Class III subjects. Part 1: a retrospective study evaluating postsurgical outcomes

OBJECTIVE

The present study aimed to determine the site and severity of maxillomandibular asymmetry before and after orthognathic surgery in asymmetric patients.

MATERIALS AND METHODS

Presurgery and postsurgery cone beam computed tomography (CBCT) data of 21 facial asymmetry patients (7 males and 14 females, mean age: 23.0 ± 3.36 years) with soft tissue chin deviation ≥ 3 mm who had undergone bimaxillary surgery were evaluated. Seven midline and twenty bilateral hard tissue landmarks were identified for the evaluation of facial asymmetry and outcomes were assessed against age- and gender-matched control subjects.

RESULTS

In the asymmetry group, bilateral landmarks exhibited significant deviation in the mandible and midface regions. Before surgery, asymmetry was more severe at the mandibular midline and sites close to it, in the asymmetry group. Bimaxillary surgery proved to be highly effective, with a significant correction of the menton to a clinically normal value (2.90 mm, p < 0.001). After surgery, significant residual asymmetry was observed at the mental foramen (p = 0.001) in the R-L direction. Moreover, significant asymmetry persisted at the sigmoid notch (p = 0.001) in the S-I direction.

CONCLUSIONS

Mandibular midline landmarks and chin peripheral regions contribute significantly to overall facial asymmetry characteristics. Despite significant correction after bimaxillary surgery, asymmetry persisted at several sites, thereby requiring secondary correction. Comprehensive 3D presurgical planning is central for asymmetry correction in a single surgery.

CLINICAL RELEVANCE

The present study specifies the location of residual asymmetry sites and advocates the correction of those sites during initial surgery.

Surgical Orthodontic Treatment for Skeletal Class I with Facial Asymmetry and Occlusal Cant: A Case Report

Background:

Cases of facial asymmetry with chin deviation and canted occlusal plane represent a challenge in orthodontic treatment.

Case Report:

We report successful surgical orthodontic treatment for skeletal Class I with severe facial asymmetry. Miniscrew anchorage was used to decompensate the canted occlusal plane in presurgical orthodontic treatment with a fixed appliance by the intrusion of the maxillary right molars and extrusion of the left molars. Then, orthognathic surgery consisting of bilateral sagittal split osteotomy for asymmetric mandibular setback was performed. Treatment resulted in marked improvement of facial asymmetry.

Conclusion:

The use of miniscrew implant anchorage may represent a superior presurgical orthodontic treatment and expand the possibility of treatment by one-jaw surgery.

Surgical-Orthodontic Diagnosis and Treatment Planning in an Asymmetric Skeletal Class III Patient—A Case Report

The skeletal Class III pattern is characterized by a sagittal intermaxillary mesial discrepancy. This discrepancy may have an unfavorable impact on function and aesthetics, which can be aggravated by the presence of facial asymmetries. This case report describes the diagnosis and treatment planning of a 19-year-old male patient with a skeletal Class III, maxillary hypoplasia, anterior crossbite, and mandibular asymmetry. When the patient reached skeletal maturity at the end of puberty, the definitive diagnosis was skeletal Class III with hyperdivergent profile and mandibular asymmetry, and a surgical-orthodontic treatment was proposed. At the end of the treatment, bimaxillary surgical correction allowed a skeletal Class I with mandibular symmetry, improving the function of the stomatognathic system and facial aesthetics.

Comparative stability and outcomes of two surgical approaches for correction of class III asymmetry with lip or occlusal cant

OBJECTIVES

To assess and compare the stability and outcomes of the two surgical approaches for patients with roll asymmetry.

MATERIALS AND METHODS

A total of 50 adult patients were consecutively recruited for this prospective study. Patients with class III asymmetry and lip or occlusal cant who underwent bimaxillary surgery were grouped according to surgical approach: asymmetric posterior impaction on both sides (API, n = 31) and posterior impaction on one side and posterior extrusion on the other side (PIE, n = 19). Postsurgical stability and outcomes between groups were determined with cone-beam computed tomography for facial midline, lip, and occlusal cant at 1 week (T1), and at least 12-month postsurgery (T2, completion of orthodontic treatment).

RESULTS

Presurgery, the upper anterior occlusal cant and lip cant were significantly greater for the PIE group (p < 0.05). Postsurgery (T2), the mandible moved upward and rotated upward in both groups. However, the upward rotation was significantly greater in the PIE group compared with the API group. Although the two approaches resulted in significant improvements in facial symmetry, the deviation in the facial midline remained under-corrected for most API patients.

CONCLUSIONS

Patient outcomes for mandibular stability and facial symmetry differed between the two surgical approaches for correction of class III asymmetry with lip or occlusal cant.

CLINICAL RELEVANCE

The findings of this study suggest that planned over-correction is a reasonable option for the approach of asymmetric posterior impaction on both sides.

Three-dimensional analysis of lip soft tissue changes and related jaw changes in patients with skeletal class III malocclusion and facial asymmetry

OBJECTIVE

To investigate three-dimensional soft tissue changes of lips and related jaw changes in patients with skeletal class III malocclusion and facial asymmetry using cone-beam computerized tomography (CBCT).

METHOD

This study included 46 CBCT scans of patients with aforementioned character before (T1) and 6-12 months after orthognathic surgery (T2). Subjects were divided into 2 groups according to two types of orthognathic surgery namely, the one-jaw surgery group who underwent bilateral sagittal splint ramus osteotomy (BSSRO) and the two-jaw surgery group who underwent Le Fort I osteotomy and BSSRO. Mimics 19.0 software are used for model reconstruction, landmark location and three-dimensional cephalometric analysis. Descriptive statistics and correlation analyses are used to investigate jaw hard tissue and lip soft tissue changes.

RESULTS

In one-jaw group, the mandible shows changes in contour and position (p < 0.05), and the surgery causes changes of lip structure on the deviated side. While in two-jaw group, jaws only show changes in spatial position, and surgery changes contour of bilateral lips and nasolabial angle (p < 0.05). At the same time, lip symmetry increases significantly in both groups postoperatively.

CONCLUSIONS

Orthognathic surgery can improve lip aesthetics in patients with skeletal class III malocclusion and facial asymmetry. However, changes induced by two surgical approaches are different. Surgeons should have a clear acquaintance with this difference to deal with different situations.

Perception of Lip Cant as a Sign of Facial Deformity: Assessment by Laypersons and Professionals on Composite Face Photographs

OBJECTIVE

Lip cant is a feature of facial deformity and commonly seen in patients with facial asymmetry. Because of its importance in aesthetic assessment, it is necessary to define the perceptions of lip cant and investigate differences in perception between laypersons and professionals. These data were insufficient in the literature.

METHODS

Photographs of 30 male and 30 female individuals with normal faces were collected, and the lip line angles were measured. A composite facial photograph was generated from superimpositions of the normal faces. Lip line angles from 0° to 9° were made, with other facial features remaining unchanged. The test photographs were arranged in random fashion and evaluated by 64 laypersons and 30 professionals. Comparisons and cumulative frequency were performed.

RESULTS

The lip line angle from the 60 normal persons was 1.20° ± 0.94°. From the composite test photographs, the average first perception of lip cant was 3.25° 1± 1.36° in the laypersons and 1.70° ± 0.69° in the professionals. The average first perception of unacceptable lip cant was 6.40° ± 1.79° in the laypersons and 4.40°1. ± 1.65° in the professionals. Significant differences were found between the first perception and perception as unacceptable lip cant, as well as between the laypersons and the professionals. Cumulative data showed that 82.8% of the laypersons perceived lip cant at 4°, and 17.2% of them felt it aesthetically unacceptable. Few laypersons (1.6%) considered less than 4° unacceptable.

CONCLUSIONS

The data in this study provide helpful information in the evaluation of lip cant. A lip cant of 4° or more could be considered an indication for clinical management.

Three-dimensional evaluation of skeletal and dental changes in patients with skeletal class III malocclusion and facial asymmetry after surgical-orthodontic treatment

OBJECTIVE

To evaluate skeletal and dental changes in patients with skeletal Class III malocclusion and facial asymmetry after surgical-orthodontic treatment using cone-beam computerized tomography (CBCT).

METHODS

This study included forty adult patients diagnosed with skeletal Class III malocclusion and asymmetry who underwent either isolated mandibular surgery or bimaxillary surgery. CBCT scans were taken before treatment (T0), at the completion of presurgical orthodontic treatment (T1) and after treatment (T2). Mimics 17.0 and 3-Matics 7.0 were used to measure skeletal and dental parameters. Skeletal and dental changes within each group from pretreatment to posttreatment were assessed, and Pearson correlation analysis was used to analyze the correlations among skeletal changes.

RESULTS

The three-dimensional changes in condylar position were insignificant after surgical-orthodontic treatment in either group (P > 0.05). However, in the one-jaw surgery group, there were significant backward rotations of the condyle and ramus on the nondeviated side (P < 0.05), and the condyle on the deviated side rotated inward and forward significantly in the two-jaw surgery group (P < 0.05) at T2. There were no significant differences in the changes in the total alveolar bone thickness of bilateral first molars during dental decompensation (P > 0.05). The ratio between the buccal and the total bone thickness around the maxillary first molar on the deviated side decreased significantly at T1, as did those around the mandibular first molar on the nondeviated side (P < 0.05).

CONCLUSIONS

Condylar angulations were less stable after treatment (7 to 9 months after surgery) in both the one-jaw and the two-jaw surgery groups, while condylar displacements were insignificant. In addition, orthodontists should keep a watchful eye to the relative position of the root in the alveolar bone during tooth decompensation.

Surgical-orthodontic treatment for class II asymmetry: outcome and influencing factors

The study aimed to evaluate the treatment outcome of bimaxillary surgery for class II asymmetry and find the influencing factors for residual asymmetry. Cone-beam computed tomographic images of 30 adults who had bimaxillary surgery were acquired, and midline and contour landmarks of soft tissue and teeth were identified to assess treatment changes and outcome of facial asymmetry. The postoperative positional asymmetry of each osteotomy segment was also measured. After surgery, the facial midline asymmetry of the mandible, chin, and lower incisors improved significantly (all p < 0.01). However, the residual chin deviation remained as high as 2.64 ± 1.80 mm, and the influencing factors were residual shift asymmetry of the mandible (p < 0.001), chin (p < 0.001), and ramus (p = 0.001). The facial contour asymmetry was not significantly improved after surgery, and the influencing factors were the initial contour asymmetry (p < 0.001), and the residual ramus roll (p < 0.001) or yaw (p < 0.01) asymmetry. The results showed that bimaxillary surgery significantly improved midline but not contour symmetry. The postoperative midline and contour asymmetry was mainly affected by the residual shift and rotational jaw asymmetry respectively.

Comparison of Lip Line Cant Change After 1-Jaw and 2-Jaw Surgery

OBJECTIVES

The purpose of this study was to compare the lip line cant (LLC) changes after 1 and 2-jaw surgery, and to evaluate the correlations of the craniofacial factors affecting LLC.

METHODS

The study subjects were selected (LLC amount within 1.5-6.0°) from among the patients diagnosed with Class III malocclusion who underwent one (n = 20) or 2-jaw surgery (n = 20). Cone beam computed tomography images were obtained immediately before the operation (T1) and 6 months after the operation (T2). Preoperative and postoperative craniofacial measurements were obtained.

RESULTS

The study subjects showed 3.12° LLC on average before undergoing 1-jaw surgery, and their LLC changed to 1.27° after the surgery. As for 2-jaw surgery, the subjects showed 3.38° LLC on average before the surgery and 0.98° after the surgery. LLC at pre-treatment may be more affected by a cant of the occlusal plane in the mandible than maxilla. In the comparison of the value of changes of LLC, the value of 2-jaw surgery was bigger than the value of 1-jaw surgery but the difference was statistically insignificant.

LIMITATIONS

This study had a limitation in that the muscles were not considered. And the metal bracket or metal crown and bridge, however, can cause noise and blurring artifacts in CT, which can lead to a low resolution. And the limited number of the patients should be considered.

CONCLUSIONS

In correlation analysis, both pre-surgery LLC and change of LLC have correlation with almost all the craniofacial measurement. Lip-line cant of patients with facial asymmetry has higher correlation with mandibular cant than with other cants. To improve the LLC, a surgical plan should be established to minimize the mandibular cant using the computer simulation as well as the maxillary cant.

[Orthognathic surgery of mandibular asymmetry: which results can we expect with and without chin wing? A cohort out of 51 cases]

INTRODUCTION

The aim of this retrospective cohort is to evaluate the amount of postsurgical correction of soft and hard tissues in patients with mandibular asymmetries and to compare the results with and without surgery of the lower mandibular contour (chin wing…).

MATERIAL AND METHOD

Mandibular asymmetries cases of three surgeons were systematically included. The angles of deviation of the chin, bi-commissural, bi-gonic and occlusal were measured on face photography and radiography. A pre and post-surgical comparison was performed and the amount of correction was analyzed via the Wilcoxon statistical test.

RESULTS

51 patients (44 women and 7 men) were included. After surgery, the correction is significant for all measurements with an improvement of 44 to 60% depending on the measured angles. No patient is normalized but the small initial mandibular asymmetries are the closest to normal after surgery. The correction of the bi-commissural angle is controlled without being optimal (60% correction). The difficulty remains the horizontalization of the bi-gonial plan which is only corrected at 45%. Patients with mandibular margin surgery (chin wing…) showed the greatest improvement in bi-gonial (p = 0.0142) and occlusal (p = 0.0154) angles.

CONCLUSION

If surgery allows a significant correction of facial dissymmetry, this is not complete. Surgical procedures on the lower edge of the mandible such as the chin wing could provide a better correction especially for bi-gonial and occlusal angles.

Treatment outcome of bimaxillary surgery for asymmetric skeletal class II deformity

OBJECTIVES

Facial asymmetry is one of the main concerns in patients with a dentofacial deformity. The aims of the study were to (1) evaluate the changes in facial asymmetry after bimaxillary surgery for asymmetric skeletal class II deformity and (2) compare preoperative and postoperative facial asymmetry of class II patients with normal controls.

MATERIALS AND METHODS

The facial asymmetry was assessed for 30 adults (21 women and 9 men, mean age: 29.3 years) who consecutively underwent bimaxillary surgery for asymmetric skeletal class II deformity using cone-beam computed tomography before and at least 6 months after surgery. Thirty soft tissue and two dental landmarks were identified on each three-dimensional facial image, and the asymmetry index of each landmark was calculated. Results were compared with those of 30 normal control subjects (21 women and 9 men, mean age: 26.2 years) with skeletal class I structure.

RESULTS

Six months after surgery, the asymmetric index of the lower face and total face decreased significantly (17.8 ± 29.4 and 16.6 ± 29.5 mm, respectively, both p < 0.01), whereas the asymmetric index of the middle face increased significantly (1.2 ± 2.2 mm, p < 0.01). Postoperatively, 53% of the class II patients had residual chin asymmetry. The postoperative total face asymmetric index was positively correlated with the preoperative asymmetric index (r = 0.37, p < 0.05).

CONCLUSIONS

Bimaxillary surgery for patients with asymmetric class II deformity resulted in a significant improvement in lower face asymmetry. However, approximately 50% of the patients still had residual chin asymmetry. The total face postoperative asymmetry was moderately related to the initial severity of asymmetry.

CLINICAL RELEVANCE

These findings could help clinicians better understand orthognathic outcomes on different facial regions for patients with asymmetric class II deformity.

Nasal Deviation in Patients With Asymmetric Mandibular Prognathism

PURPOSE

This study was aimed to evaluate the nasal deviation in patients with asymmetric mandibular prognathism.

MATERIALS AND METHODS

Thirty-five patients with skeletal class III malocclusion were included in the study. Significant mandibular asymmetry of >4 mm menton deviation in three-dimensional (3D) reformatted cone beam computed tomography images was defined as asymmetry group (n = 20). Patients without mandibular asymmetry served as control group (n = 15). The mandibular asymmetry was evaluated pre- and postoperatively.

RESULTS

Nasal tip was significantly shifted to the deviated side of the mandible (short side) in the asymmetry group, as compared to the control group (1.5 ± 0.9 degree, P < 0.01). Alar base angle (ABA) was significantly narrower in nondeviated side (long side) than in the deviated side in asymmetry group. However, control group showed no bilateral difference in ABA. Correction of deviated mandibular prognathism by isolated mandibular surgery resulted in change in the ABA but not the columella base position or nasal asymmetry. ABA on nondeviated side significantly decreased in proportion to the amount of transverse menton movement by surgery (r = -0.560, P < 0.01).

CONCLUSION

Our results showed that mandibular chin deviation was accompanied by nasal deviation. Isolated mandibular surgery can potentially influence the alar base position on the contralateral side of deviation but not the nasal tip asymmetry. Therefore, clinicians should inform patients preoperatively of the fundamental limitation of mandibular surgery in cases with preexisting nasal asymmetry.