Three-dimensional investigation of facial surface asymmetries in skeletal malocclusion patients before and after orthodontic treatment combined with orthognathic surgery

Tooth-borne versus tooth-bone-borne rapid maxillary expanders according to a stereophotogrammetric evaluation of facial soft tissues: A randomized clinical trial

OBJECTIVES

To evaluate the effects of tooth-borne and tooth-bone-borne rapid maxillary expansion (RME) on soft tissue with stereophotogrammetry.

SETTING AND SAMPLE POPULATION

Thirty two patients (15 males and 17 females) who met inclusion criteria were divided into two groups. In the first group, tooth-borne RME appliance (hyrax) was applied to 16 patients (9 males and 7 females mean age 13.4 ± 1.3 years), and in the second group, tooth-bone-borne RME appliance (hybrid hyrax) was applied to 16 patients (6 males and 10 females, mean age 13.05 ± 1.24 years).

MATERIALS AND METHODS

Changes in soft tissues before RME (T0) and post-retention (T1) period were evaluated by stereophotogrammetry. Linear and angular measurements were performed. Independent- and dependent-sample t tests were used to compare intra- and inter-group differences at P < .05 significance level.

RESULTS

The data revealed statistically significant changes in nasal width, mid-face width, upper lip vermillion length/lower lip vermillion length ratio and upper lip angle in hyrax group. (P < .05) Also nasal width, lower lip length, lower lip vermillion length, anterior face height, lower face height, convexity angle and mandibular angle showed statistically significant changes in hybrid hyrax group. (P < .05) In the inter-group evaluation, no significant differences were found except upper lip and mandible angle. (P < .05).

CONCLUSION

Both hyrax and hybrid hyrax expanders had effects on soft tissue profile. Anterior face height and lower face height increased in both groups. Upper lip length increased by 0.36 mm in the hybrid group and 0.10 mm in the hyrax group.

TRIAL REGISTRATION

This trial was registered at Clinicaltrials.gov (Identifier: NCT04828213).

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.

[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.

Applying artificial intelligence to assess the impact of orthognathic treatment on facial attractiveness and estimated age

This observational study aimed to use artificial intelligence to describe the impact of orthognathic treatment on facial attractiveness and age appearance. Pre- and post-treatment photographs (n=2164) of 146 consecutive orthognathic patients were collected for this longitudinal retrospective single-centre study. Every image was annotated with patient-related data (age; sex; malocclusion; performed surgery). For every image, facial attractiveness (score: 0-100) and apparent age were established with dedicated convolutional neural networks trained on >0.5million images for age estimation and with >17million ratings for attractiveness. Results for pre- and post-treatment photographs were averaged for every patient separately, and apparent age compared to real age (appearance). Changes in appearance and facial attractiveness were statistically examined. Analyses were performed on the entire sample and subgroups (sex; malocclusion; performed surgery). According to the algorithms, most patients' appearance improved with treatment (66.4%), resulting in younger appearance of nearly 1year [mean change: -0.93years (95% confidence interval (CI): -1.50; -0.36); p=0.002), especially after profile-altering surgery. Orthognathic treatment had similarly a beneficial effect on attractiveness in 74.7% [mean difference: 1.22 (95% CI: 0.81; 1.63); p<0.001], especially after lower jaw surgery. This investigation illustrates that artificial intelligence might be considered to score facial attractiveness and apparent age in orthognathic patients.

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.

Frontal-view nasolabial soft tissue alterations after bimaxillary orthognathic surgery in Class III patients

INTRODUCTION

The aim of this before-after clinical trial was to evaluate nasolabial soft tissue changes in the frontal plane after bimaxillary surgery.

METHODS

A total of 20 skeletal Class III Iranian patients needing bimaxillary Le Fort I osteotomy plus mandibular setback surgery were enrolled in this trial. Patients underwent 4.02 ± 1.02 mm of maxillary advancement (Le Fort I osteotomy, 4.33 ± 1.21 mm in men, 3.81 ± 0.86 mm in women) and 7.13 ± 1.74 mm of mandibular setback (intraoral vertical ramus osteotomy, 7.71 ± 2.33 mm in men, and 6.74 ± 1.16 mm in women). Data were acquired via 2D frontal photographs. We compared pretreatment baseline (T ₁), preoperative postorthodontic treatment (T ₂), and postoperative (T ₃) anthropometric measurements using repeated-measures ANOVA and Bonferroni tests (α = 0.05).

RESULT

The 20 patients (12 men, 8 women) were aged 21.85 ± 1.75 years. Between T ₁ and T ₂, nasal width, cutaneous upper labial heights increased overall; cutaneous lower labial height decreased (P < 0.05). Between T ₂ and T ₃, nasal width, widths of the philtrum and mouth, cutaneous upper-lip height, vermilion height of the lower lip, lateral upper-lip height increased; the upper-lip vermilion height and cutaneous lower lip height decreased (P < 0.05). The changes ranged between 0.5 and 5 mm.

CONCLUSION

The applied orthognathic surgery procedures might widen the alar base and mouth width. It might increase the lateral upper-lip height, vermilion height of the lower lip, and cutaneous and overall upper-lip heights while reducing upper-lip vermilion height and shortening the overall lower-lip height.