Three-dimensional facial surface analysis of patients with skeletal malocclusion

Hyperbaric CO2 Cryotherapy for Managing Swelling After Mandibular Angle Ostectomy

ABSTRACT

Postoperative facial swelling after mandibular angle ostectomy is a concern for patients as it affects their quality of life. This study aimed to evaluate the effect of hyperbaric CO2 cryotherapy in relieving postoperative swelling. Thirty-seven patients (mean age: 22.95 ± 3.49 years) who underwent bilateral mandibular angle ostectomy from April to October 2019, were included in this study. A split-mouth design was adopted and through a random sequence, either side of the face was designated as the experimental side. Both received routine nursing care, while the experimental side underwent an additional hyperbaric CO2 cryotherapy treatment. The facial structure was recorded by a 3-dimensional laser scanner pre- and postoperatively. Geomagic Studio was used for alignment, visualization, and quantification of the swelling. The largest deviation value on each side was adopted to assess the overall swelling. Parameters were compared using the paired t-test, and P<0.05 was considered statistically significant. No necrosis of the skin and adjacent structures or other complications occurred in these patients. After the first day of cryotherapy, the deviation in the experimental and the control groups was (8.40 ± 1.95) mm and (10.42 ± 2.03) mm, respectively. The next day, after cryotherapy, the value further reduced to (5.42 ± 1.36) mm and (8.24 ± 2.22) mm for the experimental and control groups, respectively. And the effect remained till the seventh day. No difference was observed in terms of volume of drainage. Hyperbaric CO2 cryotherapy is safe and effective in relieving postoperative swelling and seems to be more effective than the traditional cold-pack treatment after mandibular angle ostectomy.

Reliability of the Linear Measurement (Contact) Method Compared with Stereophotogrammetry (Optical Scanning) for the Evaluation of Edema after Surgically Assisted Rapid Maxillary Expansion

Many techniques have been developed to evaluate facial swelling after maxillofacial surgeries. Patients who undergo surgically assisted rapid maxillary expansion (SARME) develop facial edema more often than those who undergo minor oral surgeries. Reliable systems to assess soft tissue dimensions offer many advantages for documentation and treatment planning across surgical fields. (1) Background: The objective assessment of facial swelling is advantageous as it allows the evaluation of the effect of anti-inflammatory drugs. Therefore, this study aimed to compare the reliabilities of linear measurement method and optical scanning for the objective assessment of facial swelling after SARME. (2) Methods: Sixteen (12 women and 4 men) patients were enrolled. Linear measurements between guide points and facial scans were obtained for the left and right sides preoperatively and 1, 2, and 5 days after SARME. Preoperative values were subtracted from each post-operative value and the differences were compared between the two measurement methods. (3) Results: There were no statistically significant differences between the right and left sides at any time point in the measurements with either method. (4) Conclusions: Recently, stereophotogrammetry has been considered the first choice method for evaluating facial swelling. Furthermore, we found a strong correlation between volumetric analysis and linear measurement at all time points and for both sides.

Three-dimensional Morphing and Its Added Value in the Rhinoplasty Consult

Background:

The evolving literature on 3D surface imaging demonstrates that this technology is becoming the preferred simulation technique in hospitals and research centers. However, no study has demonstrated before the superiority of this facility over standard 2D simulation during preoperative evaluation in rhinoplasty.

Methods:

One hundred seventy-two consecutive patients requesting rhinoplasty were included. Patients answered a questionnaire following a 2D simulation and subsequently experienced 3D morphing. A single question was answered regarding the added value of the latter by patients and surgeons, respectively.

Results:

In our survey, satisfaction with 2D morphing reached 61%. Ninety-five percentage of the same group considered 3D simulation an added value over 2D. Additionally, 84% of patients requesting revision rhinoplasty admitted that 3D computer simulation has helped them understand the aims of surgery, in contrast to 61% of patients from the primary group. Furthermore, patients unsatisfied with their 2D simulation got reassured following 3D simulation to undergo surgery at a higher percentage (67%), compared with the group initially satisfied with 2D (48%). Women appeared reassured by 3D imaging in higher percentage (63%) compared with men (42%). The 2 surgeons, however, found 3D simulations to be an added value in 66% and 74% of all patients.

Conclusions:

The overwhelming majority of our patients considered 3D simulation an added value over 2D. Patients initially unsatisfied with 2D morphing, revision rhinoplasty patients, and women seemed to be the groups that appreciated more 3D than 2D computer simulation. In contrast, surgeons considered the facility of 3D an added value in two-thirds of the patients.

The effect of hard tissue surgical changes on soft tissue displacement: a pilot CBCT study

INTRODUCTION

This pilot study had as main objective to test the reliability of a new method to evaluate orthognathic surgery outcomes and also, to understand the effect of hard tissue changes on soft tissue displacement.

METHODS

The sample consisted of eight patients that underwent bimaxillary advancement and had CBCT at two time points (before surgery and 6-8 months follow-up). Voxel-based cranial base superimposition was used to register the scans. A different technique of iterative closest point (ICP) was used to measure and correlate the changes. The average displacement of 15 areas (4 hard tissue and 11 soft tissue) were measured twice.

RESULTS

ICC was > 0.99 for all areas. Changes in the tip of the nose did not correlate with changes in any maxillary area, whereas soft tissue A point, A point and upper lips had correlation with several areas. The highest correlation for the maxilla was between the upper lip and the left/right supra cheilion (p< 0.001, r= 0.91 and p< 0.001, r= 0.93, respectively). In the mandible, the majority of the correlations involved soft tissue pogonion, pogonion and lower incisors, with the strongest one between pogonion and lower incisors (p< 0.001, r= 0.98).

CONCLUSION

With the proper case selection, ICP is a reliable method that can be used to assess three-dimensional changes.

Changes in buccal facial depth of female patients after extraction and nonextraction orthodontic treatments: A preliminary study

OBJECTIVE

This study was performed to investigate buccal facial depth (BFD) changes after extraction and nonextraction orthodontic treatments in post-adolescent and adult female patients, and to explore possible influencing factors.

METHODS

Twelve and nine female patients were enrolled in the extraction and nonextraction groups, respectively. Changes in BFD in the defined buccal region and six transverse and two coronal measuring planes were measured after registering pretreatment and posttreatment three-dimensional facial scans. Changes in posterior dentoalveolar arch widths were also measured. Treatment duration, changes in body mass index (BMI), and cephalometric variables were compared between the groups.

RESULTS

BFD in the buccal region decreased by approximately 1.45 mm in the extraction group, but no significant change was observed in the nonextraction group. In the extraction group, the decrease in BFD was identical between the two coronal measuring planes, whereas this differed among the six transverse measuring planes. Posterior dentoalveolar arch widths decreased in the extraction group, whereas these increased at the second premolar level in the nonextraction group. The treatment duration of the extraction group was twice that of the nonextraction group. No differences were found in BMI and Frankfort horizontal-mandibular plane angle changes between the groups. BFD changes in the buccal region moderately correlated with treatment duration and dental arch width change.

CONCLUSIONS

BFD decreased in adult female patients undergoing extraction, and this may be influenced by the long treatment duration and constriction of dentoalveolar arch width. However, nonextraction treatment did not significantly alter BFD.

Three-dimensional analysis of facial morphology

OBJECTIVES

The objectives of this study were to evaluate sexual dimorphism for facial features within Chinese and African American populations and to compare the facial morphology by sex between these 2 populations.

MATERIALS AND METHODS

Three-dimensional facial images were acquired by using the portable 3dMDface System, which captured 189 subjects from 2 population groups of Chinese (n = 72) and African American (n = 117). Each population was categorized into male and female groups for evaluation. All subjects in the groups were aged between 18 and 30 years and had no apparent facial anomalies. A total of 23 anthropometric landmarks were identified on the three-dimensional faces of each subject. Twenty-one measurements in 4 regions, including 19 distances and 2 angles, were not only calculated but also compared within and between the Chinese and African American populations. The Student's t-test was used to analyze each data set obtained within each subgroup.

RESULTS

Distinct facial differences were presented between the examined subgroups. When comparing the sex differences of facial morphology in the Chinese population, significant differences were noted in 71.43% of the parameters calculated, and the same proportion was found in the African American group. The facial morphologic differences between the Chinese and African American populations were evaluated by sex. The proportion of significant differences in the parameters calculated was 90.48% for females and 95.24% for males between the 2 populations. The African American population had a more convex profile and greater face width than those of the Chinese population.

CONCLUSIONS

Sexual dimorphism for facial features was presented in both the Chinese and African American populations. In addition, there were significant differences in facial morphology between these 2 populations.

Three-dimensional analysis of soft tissue changes in full-face view after surgical correction of skeletal class III malocclusion

OBJECTIVE

The objective of this study was to evaluate changes in soft tissue in full-face view because of surgical correction of skeletal Class III malocclusion, using 3-dimensional (3D) laser scanning.

METHODS

Twenty-seven subjects with skeletal Class III malocclusion [11 males; mean age (SD), 24.0 (5.7) years] underwent bilateral sagittal split ramus osteotomy for mandibular setback combined with Lefort I osteotomy with/without maxillary advancement. Twelve patients (group 1) had mandibular setback surgery, and the other 15 (group 2) had combination surgery. Lateral cephalograms and 3D facial scan images were assessed preoperatively and postoperatively. The facial widths upon superimposition of 3D facial images were measured in the same coordinates using a Rapidform 2006 system. Paired and independent t tests were done for statistical analysis.

RESULTS

The midface soft tissue broadened significantly above the cheilion plane postoperatively (P < 0.05). A larger change was observed nearer to subnasale plane, and a similar trend was seen among the horizontal planes in 1- or 2-jaw surgery groups. The widths from the exocanthion plane to the subnasale plane increased more in group 2 [mean (SD), 4.45 (2.45) mm, 8.71 (2.92) mm, and 7.62 (3.13) mm] than those in group 1 [mean (SD), 1.26 (0.97) mm, 1.84 (1.06) mm, and 1.35 (0.65) mm], and this difference was significant (P < 0.05). There was a decrease below the cheilion plane with mandibular setback between groups, but this difference was not significant.

CONCLUSIONS

The measurement method used here for the shape outline of the lateral parts of the face could provide quantitative data for the clinical evaluation and objective analysis of the human face in full-face view. The midface soft tissue in subjects with skeletal Class III malocclusion exhibited a greater increase in width after bimaxillary surgery procedures than mandibular setback-only surgery.

Frontal soft tissue analysis using a 3 dimensional camera following two-jaw rotational orthognathic surgery in skeletal class III patients

Although two dimensional cephalometry is the standard method for analyzing the results of orthognathic surgery, it has potential limits in frontal soft tissue analysis. We have utilized a 3 dimensional camera to examine changes in soft tissue landmarks in patients with skeletal class III dentofacial deformity who underwent two-jaw rotational setback surgery. We assessed 25 consecutive Asian patients (mean age, 22 years; range, 17-32 years) with skeletal class III dentofacial deformities who underwent two-jaw rotational surgery without maxillary advancement. Using a 3D camera, we analyzed changes in facial proportions, including vertical and horizontal dimensions, facial surface areas, nose profile, lip contour, and soft tissue cheek convexity, as well as landmarks related to facial symmetry. The average mandibular setback was 10.7 mm (range: 5-17 mm). The average SNA changed from 77.4° to 77.8°, the average SNB from 89.2° to 81.1°, and the average occlusal plane from 8.7° to 11.4°. The mid third vertical dimension changed from 58.8 mm to 57.8 mm (p = 0.059), and the lower third vertical dimension changed from 70.4 mm to 68.2 mm (p = 0.0006). The average bigonial width decreased from 113.5 mm to 109.2 mm (p = 0.0028), the alar width increased from 34.7 mm to 36.1 mm (p-value = 0.0002), and lip length was unchanged. Mean mid and lower facial surface areas decreased significantly, from 171.8 cm(2) to 166.2 cm(2) (p = 0.026) and from 71.23 cm(2) to 61.9 cm(2) (p < 0.0001), respectively. Cheek convexity increased significantly, from 171.8° to 155.9° (p = 0.0007). The 3D camera was effective in frontal soft tissue analysis for orthognathic surgery, and enabled quantitative analysis of changes in frontal soft tissue landmarks and facial proportions that were not possible with conventional 2D cephalometric analysis.

A contact-free volumetric measurement of facial volume after third molar osteotomy: proof of concept

OBJECTIVE

The present study tested the reliability of an optical scanning device for the objective assessment of postoperative facial swelling.

STUDY DESIGN

Twenty control subjects bearing a defined volume of water (10-30 mL) in an intraorally carried balloon were tested to assess the measurement accuracy of the device. As a proof of concept, facial volumes of 59 surgical cases were recorded before osteotomy and 1 and 7 days after intervention with the use of a structured light scanner.

RESULTS

The median difference between the applied and the measured volumes was 0.67 mL for the control test with the artificial swelling simulated using water balloons. For subjects having third molar osteotomy, extraoral volume increased to 5.29 cm(3) 1 day after surgery (95% CI 5.22-8.52) and decreased to 0.00 mL (95% CI 0.85-2.55) after 7 days.

CONCLUSIONS

Contact-free visible-light 3-dimensional scanning is reliable for the objective assessment of postoperative facial swelling.