Soft tissue facial changes among adult females during alignment stage of orthodontic treatment: a 3D geometric morphometric study

Education on the Importance of Doctor-patient Communication in Orthodontic Clinical Teaching

In the process of orthodontic clinical teaching, it is very important to teach medical students how they are expected to communicate effectively with patients and their families, as this has a direct impact on patient compliance throughout the process of diagnosis and treatment and on patient satisfaction after treatment. Doctor-patient communication is therefore an essential skill for medical students to gain before taking up clinical work. In view of the problems that are often encountered in each stage of orthodontic treatment, the present paper discusses the specific content of doctor-patient communication education in clinical teaching. The discussion is given in both theoretical and practical terms to lay a solid foundation for improving the overall quality of medical service provided by medical students in teaching hospitals and establishing a harmonious medical environment.

Three-Dimensional Evaluation of Changes in the Nose and Upper Lip After Secondary Alveolar Bone Grafting in Patients With Unilateral Cleft Lip and Palate

INTRODUCTION

Alveolar bone grafting (ABG) influences facial soft tissue changes, but the precise effects on the nose and upper lip remain unclear. This study used three-dimensional (3D) facial images to evaluate nose and upper lip alterations after ABG. We further enhanced the visualisation of these changes by generating 3D superimpositions, colour maps and deviation analyses of key critical landmarks in these regions.

MATERIALS AND METHODS

Forty patients (8-20 years old) with non-syndromic unilateral cleft lip and cleft palate (UCLP) underwent ABG using the iliac bone from September 2022 to September 2023. Three-dimensional facial images were analysed 1 month before and 3 months after surgery to evaluate the spatial displacement of 18 nose and upper lip landmarks to assess changes after ABG. Colour maps were constructed, and 3D deviation analysis was also performed. Paired sample t tests and Wilcoxon's signed-rank tests were used to analyse alterations.

RESULTS

The 3D analysis uncovered significant forward movement on the cleft side only. This included nasal alar, alar curvature and subalar points. The labrale superius of the upper lip showed similar movement. Conversely, other landmarks showed minimal changes in all directions.

CONCLUSIONS

ABG can improve the nasal contour on the cleft side. After ABG, significant forward movement occurs in the cleft side of the nasal alar, alar curvature and subalar regions. Although these changes are minimal, they contribute to the overall improvement in facial aesthetics.

Using a structured light scanner to evaluate 3-dimensional soft-tissue changes after extracting 4 premolars in young adult female patients

INTRODUCTION

Facial esthetics have always received much attention in orthodontic treatment, especially in young adult female patients. Three-dimensional (3D) soft-tissue changes after orthodontic extraction have not been fully explained. This study evaluated the 3D morphologic changes after orthodontic extraction in young female patients using a structured light scanner.

METHODS

Forty-five adult female patients aged 20-25 years were enrolled in our study. The treatment group consisted of patients who received orthodontic treatment with 4 premolar extractions, and the control group was composed of young female volunteers who had not undergone any orthodontic treatment. To monitor the soft-tissue changes, 9 morphologic regions and 12 landmarks were identified for the 3D deviation analyses. The spatial deviations of landmarks and regions in the x, y, and z directions were constructed for quantitative analysis. Color map images were constructed to visualize soft-tissue displacement as a qualitative evaluation. The paired sample test was used to compare differences at the beginning of the experiment (T0) and after 24 months (T1) in both groups. An independent t test with Bonferroni correction was performed to compare differences between the treatment and control groups. A linear regression test was performed between incisor retraction and changes in the perioral tissues.

RESULTS

Subtracting the effect of aging from the lip changes in the control group, the treatment group showed a statistically significant difference in the displacement of labrale superius (-1.37 mm), labrale inferius (-1.89 mm), the upper lip region (-0.98 mm), and the lower lip region (-1.36 mm) along the z-axis. No significant differences were found between the treatment and control groups in the temporal, parotideomasseteric, and buccal regions. Pearson correlation tests indicated a positive correlation between incisor tip retraction and changes in soft tissues (two-dimensional cephalometric analysis, 3D landmark measurements, and 3D regional measurements). The correlation coefficient ranged between 0.45 and 0.55.

CONCLUSIONS

Three-dimensional soft-tissue changes were mainly concentrated in the upper and lower lip regions in adult female patients after the 4 premolars were extracted. For female patients aged 20-25 years with 4 extracted premolars, soft-tissue changes in the temporal, parotideomasseteric, and buccal regions were not clinically significant.

Three-dimensional soft tissue landmark detection with marching cube algorithm

Current method of analyzing three-dimensional soft tissue data, especially in the frontal view, is subjective and has poor reliability. To overcome this limitation, the present study aimed to introduce a new method of analyzing soft tissue data reconstructed by marching cube algorithm (Program S) and compare it with a commercially available program (Program A). Cone-beam computed tomography images of 42 patients were included. Two orthodontists digitized six landmarks (pronasale, columella, upper and lower lip, right and left cheek) twice using both programs in two-week intervals, and the reliability was compared. Furthermore, computer-calculated point (CC point) was developed to evaluate whether human error could be reduced. The results showed that the intra- and inter-examiner reliability of Program S (99.7-100% and 99.9-100%, respectively) were higher than that of Program A (64.0-99.9% and 76.1-99.9%, respectively). Moreover, the inter-examiner difference of coordinate values and distances for all six landmarks in Program S was lower than Program A. Lastly, CC point was provided as a consistent single point. Therefore, it was validated that this new methodology can increase the intra- and inter-examiner reliability of soft tissue landmark digitation and CC point can be used as a landmark to reduce human error.

Analyzing the effects of tooth extraction on the lip in orthodontic treatment

INTRODUCTION

The aim of this study was to analyze changes occurring in the lip and facial soft-tissue profile after fixed orthodontic treatment, with or without tooth extraction, in patients with dental class II malocclusion.

MATERIALS AND METHODS

Measurements were made on cephalometric films of 75 individuals with dental class II malocclusion before and after fixed orthodontic treatment. The patients were divided into three groups: no extraction, extraction of upper two premolars, or extraction of four premolars. The parameters measured were: basic upper lip thickness (BULT), vermilion upper lip thickness (VULT), upper lip inclination (ULI), basic lower lip thickness (BLLT), vermilion lower lip thickness (VLLT), lower lip inclination (LLI), face axis angle (Ba-N/PtmGn), labiomental angle, facial convexity angle, and total face convexity angle. The results were analyzed statistically using the Wilcoxon, Kruskal-Wallis, and Mann-Whitney U tests.

RESULTS

It was found that the VULT value in the group with no extraction was lower than the four-extraction group (P = 0.001; P < 0.05). The VULT value in the upper-two extraction group was significantly lower than that in the four-extraction group, and the Ba-N/PtmGn in the no-extraction group was lower than that in the four-extraction group (P = 0.001; P < 0.05).

CONCLUSIONS

These findings suggest that tooth extraction in orthodontic treatment may affect the vermilion upper lip thickness and facial axis, but that this does not have any negative effects on the soft-tissue facial profile. Premolar tooth extraction can be performed by establishing an accurate diagnosis and treatment plan to avoid undesirable and negative effects on the facial soft-tissue profile.

Profiles of facial soft tissue changes during and after orthodontic treatment in female adults

Background

Some female adults who received orthodontic treatment often complain about thinner faces, protruding cheekbones and sunken temples, even at the beginning of treatment. The present research aimed to explore facial soft tissue changes during and after orthodontic treatment, as well as the related factors affecting facial soft tissue changes.

Methods

This study used 3dMD stereo photography technology to compare facial soft tissue changes among adult females who received orthodontics. A total of 52 adult females (24 teeth extraction, 28 non-teeth extraction cases) were included and potential correlations between related factors (facial morphology features, the change of occlusal height and dental arch width) were evaluated during different treatment periods.

Results

Overall, 3D-negative soft tissue changes of the buccal region moderately correlated with distances of nasion-menton and subnasale-menton (both rs = 0.30, P < 0.05) as well as the ratio of subnasale-menton/right gonion-left gonion (rs = 0.33, P < 0.05) and nasion-menton/right zygomatic point-left zygomatic point (rs = 0.30, P < 0.05). Among the 3D angle measurements, the right chelion-median upper lip point-left chelion angle was found to have a moderate correlation with 3D negative changes of the upper cheilion region (rs = 0.31, P < 0.01). Analysis of occlusal height changes revealed that an increase in the posterior facial height (nasion-gonial distance) may be a risk factor for negative changes in the zygomatic arch area. In addition, a moderate positive correlation between the maxillary first molar width changes and 3D-negative changes of the lower cheek region was found (rs = 0.41, P < 0.05).

Conclusions

After orthodontic treatment, adult females with wide and short faces may be prone to negative soft tissue changes. Changes of posterior facial height and arch width between the first molars were also risk factors for negative changes of facial soft tissues. Extraction is not a major factor producing facial soft tissue changes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-022-02280-5.