Assessed facial normality after Twin Block therapy

Comparing Direct Measurements and Three-Dimensional (3D) Scans for Evaluating Facial Soft Tissue

The inspection of patients' soft tissues and the effects of various dental procedures on their facial physiognomy are quite challenging. To minimise discomfort and simplify the process of manual measuring, we performed facial scanning and computer measurement of experimentally determined demarcation lines. Images were acquired using a low-cost 3D scanner. Two consecutive scans were obtained from 39 participants, to test the scanner repeatability. An additional ten persons were scanned before and after forward movement of the mandible (predicted treatment outcome). Sensor technology that combines red, green, and blue (RGB) data with depth information (RGBD) integration was used for merging frames into a 3D object. For proper comparison, the resulting images were registered together, which was performed with ICP (Iterative Closest Point)-based techniques. Measurements on 3D images were performed using the exact distance algorithm. One operator measured the same demarcation lines directly on participants; repeatability was tested (intra-class correlations). The results showed that the 3D face scans were reproducible with high accuracy (mean difference between repeated scans <1%); the actual measurements were repeatable to some extent (excellent only for the tragus-pogonion demarcation line); computational measurements were accurate, repeatable, and comparable to the actual measurements. Three dimensional (3D) facial scans can be used as a faster, more comfortable for patients, and more accurate technique to detect and quantify changes in facial soft tissue resulting from various dental procedures.

The Esthetic Difference of Chinese Beauty Evaluated by Two Different Human Races Based on Three-Dimensional Average Face Analysis

Supplemental Digital Content is available in the text

Purpose:

The aim of this study was to establish a new method of facial soft tissue analysis based on 3dMDface system and to find the different esthetic preferences of Chinese beauties from the Chinese and Indian evaluators perspective.

Methods:

Three-dimensional facial images of 242 females and 168 males were evaluated and ranked by 8 Chinese and nine Indians using a 10-point visual analog scale (VAS). Total 120 subjects in 2 panels (from Chinese perspective and Indian perspective) including 30 male and 30 female faces with top 30 scores were analyzed with the “average face” method respectively. Then 17 linear measurements, 13 curve measurements and 14 ratios of 4 average faces were calculated and compared with the divine proportion.

Results:

Distinct differences were founded based on the average face analysis. Similar total facial types were preferred by both Chinese and Indian evaluators, while Indian evaluators preferred a wider male face with a protrusive lower lip. Delicate noses with lower nose ridge but protrusive lower lips in females were more acceptable by Indian evaluators. The differences of linear measurements were limited in 2.0 mm except the facial width, lower facial width, upper facial height and forehead height while curve measurements differ distinctly as the table shows. No ratios equal to the divine proportion were founded.

Conclusion:

The 3D Average face based on stereophotogrammetry is a feasible method to analyze the facial characters and discrepancy of esthetic preferences. Chinese and Indian evaluators have some certain differences when judging beauties. Attractive faces have some certain ratios but not the divine proportion.

Expert panels as a reference standard in orthodontic research: An assessment of published methods and reporting

INTRODUCTION

The aim of this study was to investigate the expert panel methodology applied in orthodontics and its reporting quality. Additionally, the relationship between the reporting quality and a range of variables was explored.

METHODS

PubMed was searched for orthodontic studies in which the final diagnosis or assessment was made by 2 or more experts published up to March 16, 2015. Reporting quality assessment was conducted using an established modified checklist. The relationship between potential predictors and the total score was assessed using univariable linear regression.

RESULTS

We identified 237 studies with a mean score of 9.97 (SD, 1.12) out of a maximum of 15. Critical information about panel methodology was missing in all studies. The panel composition differed substantially across studies, ranging from 2 to 646 panel members, with large variations in the expertise represented. Only 17 studies (7.2%) reported sample size calculations to justify the panel size. Panel members were partly blinded in 65 (27.4%) studies. Most studies failed to report which statistic was used to compute intrarater (65.8%) and interrater (66.2%) agreements. Journal type (nonorthodontic: β, 0.23; 95% CI, -0.07 to 0.54 compared with orthodontic), publication year (β, 0; 95% CI, -0.02 to 0.02 for each additional year), number of authors (1-3: β, 0.30; 95% CI, -0.13 to 0.74 compared with at least 6; 4-5: β, 0.18; 95% CI, -0.29 to 0.33 compared with at least 6), and number of centers involved (single: β, 0.20; 95% CI, -0.14 to 0.54 compared with multicenter) were not significant predictors of improved reporting. Studies published in Asia and Australia had significantly lower scores compared with those published in Europe (β, -0.54; 95% CI, -0.92 to -0.17).

CONCLUSIONS

Formal guidelines on methodology and reporting of studies involving expert panels are required.

An extended period of functional appliance therapy: a controlled clinical trial comparing the Twin Block and Dynamax appliances

The aim of this clinical trial was to compare the hard- and soft-tissue effects of 15 month full-time functional appliance therapy with Twin Block (TB) and Dynamax (Dx) appliances. The effects on both hard and soft tissue were analysed using cephalograms and three-dimensional optical surface laser scans. One hundred and three subjects with a class II division 1 malocclusion, and a minimum overjet of 7mm were available for analysis following stratified randomization according to gender and age. Data was collected at the start of treatment, 15 month therapy, and after 3 month post-treatment observation. Statistical analysis was conducted using analysis of covariance. The results demonstrated both appliances corrected the overjet with significantly increased skeletal dimensional changes with the TB compared with the Dx with forward movement of pogonion of 5.2mm (TB) and 0.7mm (Dx) P = 0.003. In addition, significant changes occurred particularly in the vertical dimension where there was also an increase in total anterior face height in both groups (TB = 6.4mm, Dx = 5.5mm) and significant (P = 0.003) mandibular length changes were also observed (TB = 7.2mm, Dx = 3.8mm). The cephalometric soft-tissue changes were significantly different between the two appliances at soft-tissue pogonion (TB = 9.8mm, Dx = 4.6mm, P = 0.001). Laser scan three-dimansional changes showed significant difference in the lower labial sulcus region where forward movements were observed (TB = 8.2mm, Dx = 6.2mm; P = 0.04). Overall these changes appear to be greater and more stable than those achieved in a previous 9 month study.