A Study Of Soft Tissue Changes At The Third Month Of Orthodontic Treatment Of Female Adults By Three-dimensional Stereophotogrammetry

ObjectiveMany people seek to improve their appearance resort to orthodontics as their instinct to pursue beauty.In recent years,the phenomenon of soft tissue depression in cheek and temple during orthodontic treatment are noticed by more and more females.This experiment was designed to explore the soft tissue changes during orthodontic treatment by means of three-dimensional stereophotogrammetry.We used three-dimensional stereophotogrammetry system to record three-dimensional images of facial soft tissue of adult female patients at the beginning,the third,the sixth and the twelfth months of orthodontics.The images were superimposed to compare one's soft tissue,we tried to clarify the areas and regularity of soft tissue changes,and to compare the effects of extraction and non-extraction orthodontic treatment on these changes.This would help orthodontists to communicate with patients better,avoid disputes and provide theoretical basis for treatment planning.Method1.Five undergraduates of Tianjin Medical University were selected to take three-dimensional images of facial soft tissues every 7 days.Geomagic Design X software was used to superimpose the images,measure the changes of markers,record data and input into SPSS software for t-test.2.We selected 38 female patients(25-35 years old)in the Orthodontic Department of Tianjin Stomatological Hospital who were having non-extraction treatment.Three-dimensional facial images were captured at the beginning and the third month during orthodontic treatment.The images were superimposed and the changes of soft tissue at landmarks were measured by Geomagic Design X software.We used SPSS to record the data and calculate the average values.3.We selected 51 female patients(25-35 years old)in the Orthodontic Department of Tianjin Stomatological Hospital who were having extraction treatment.Three-dimensional facial images were captured at the beginning and the third during orthodontic treatment.The images were superimposed to measure the changes at Cheek Point(Ck).T-test was performed to compare this data and former data.Outcome1.The changes of soft tissue at each landmark were less than 0.3 mm,with no statistical difference.2.At the third month,the average changes of soft tissue at facial landmarks were as follows: G-0.05 mm,N 0.04 mm,Prn 0.09 mm,Ls 0.37 mm,Li 0.10 mm,Pog -0.40 mm,Me-0.14 mm,Osr-0.57 mm,Osl-0.67 mm,Orr-1.64 mm,Orl -1.20 mm,Zyr 0.18 mm,Zyl-0.16 mm,Tpr-0.60 mm,Tpl-0.57 mm,Par -0.99 mm,Pal-1.06 mm,Ckr-2.06 mm,Ckl-2.09 mm,Mnr-0.37 mm,Mnl -0.38 mm.3.At the third month during treatment,the difference between the non-extraction group and the extraction group was not statistically significant.Conclusion1.The facial landmarks of facial soft tissue have high repeatability and stability at different time point,which meet the clinical requirements;2.There is a tendency of negative changes in facial soft tissue of adult females during orthodontic treatment.3.The tendency of negative changes occurred in both extraction groups and non-extraction groups.