Craniofacial Characteristics And Dynamic Analysis Of Smile Expression In Chinese Adults Population Of Han Nationality

Objectives: Craniofacial deformity, maxillofacial trauma, surgicalrestoration and orthodontic treatment need to be designed according to itsstructure and function while the design should be considered from theperspective of aesthetics. At present, the overseas researchers in orthodontics,orthognathic, aesthetic medicine, plastic surgery and other disciplines made amore in-depth study of facial aesthetic evaluation, while our country relativelydid few. The aim of this study was to make esthetic evaluation in Chineseadults with well-balance profiles by Steiner analysis, Ricketts analysis, Downsanalysis, Wylie analysis, Tweed analysis, McNamara analysis, Holdawayanalysis, Burstone analysis. The three-dimensional (3D) craniofacialmeasurements were performed through3D Camega scan system. The databaseof quantitative measurement of three-dimensional craniofacial tissue ofChinese adults with well-balance profiles was established. This database wasavailable for diagnosis and therapy of craniomaxillofacial deficiency. Also, thisdatabase was attributed to Virtual Reality Orthopedic Surgery System. To findout the dynamic smile characteristics of Chinese adults with well-balanceprofiles in3D optical scanning method, which were the essential data forclinical examination, diagnosis, perspective prognosis and assessment.Methods: Two categories of objects included in the research: populationwith well-balance profiles group from the normal popution with the idealocclusion and Angle â…¡popution group. And the standards of the normalpopution are as follows:â‘ in near ideal occlusion standard, neutral molarrelationship, normal overbite, normal overbite;â‘¡well-balance andequilibrium profile;â‘¢symmetrical face and three parts of one thirdscoordinate;â‘£no plastic surgery and no orthodontic and orthognathictreatment history;⑤the mouth opening at the normal range, no temporomandibular disorders;â‘¥in goodhealth and the teeth well-developed.The population with well-balance profiles group was selected after step1byevaluating the lateral profiles of the the normal popution with the idealocclusion. Chinese lay judges evaluated each of the sujects' profiles after step1that were projected on the screen for30seconds. Each profile was evaluatedas very pleasant (5points), pleasant (4points), average (3points), belowaverage (2points), and unpleasant (1point). The scores for each profile wererecorded and calculated. Subjects who were unanimously rated as pleasing (3or4points) by the judges were included as the sample. The standards of Angleâ…¡ popution are as follows:â‘ in good health and no systemic disease;â‘¡bilateralmolar relationship with Class â…¡ occlusion and facial skull typewith Class â…¡;â‘¢no plastic surgery and no orthodontic and orthognathictreatment history.Part1: The study was taken of5500subjects who were students at HebeiMedical University, the Shijiazhuang University of Economics. After step1,from5500students,50men and50women satisfied the selection criteria as theideal occlusion. After the procedure of selecting population with well-balanceprofiles, the sample included56profiles (25male,30female).The study was taken of the patients in clinic. And30men and30womensatisfied the selection criteria as classâ…¡ occlusion.Lateral cephalometric radiographs were taken for the normal poputionand Angle â…¡ popution. After the lateral cephalograms, soft-tissue outlineswere traced on0.003mm matte acetate papers and then scanned. A softwareprogram (Adobe Photoshop, CS5.0) was used to darken and trim the scannedprofiles to obtain black soft-tissue profiles on white backgrounds to trace andprocess these profiles, which extended from glabella to the cervical point forall subjects. This step is to select the population with well-balance profiles.All radiographs were traced and digitized by writer and reviewed threetimes every two weeks for accurate landmark identification. Each tracing wasretrieved and digitized on the computer using the Winceph CephalometricSoftware program. When all the analyses were done, the results were subjected to T testusing the SPSS program (Statistical Product and Service Solutions, USA). Thelevel of significance was set at0.05. The correlational relationship incephalometric analyses was established by the SPSS program with stepwisemethod.Part2:3D Camega scanning were taken of subjects of the popution withwell-balance profiles. The3D craniofacial soft tissue images were reformattedand3D measurements were performed in Cloudform Software program. Allimages were traced and digitized by writer and reviewed three times every twoweeks for accurate landmark identification.When all the analyses were done, the results were subjected to T testusing the SPSS program (Statistical Product and Service Solutions, USA). Thelevel of significance was set at0.05.Part3:3D Camega scanning were taken of subjects of the popution withwell-balance profiles and the Angle â…¡ popution. The3D craniofacial softtissue smile images were reformatted and3D smile measurements wereperformed in Cloudform Software program. All images were traced anddigitized by writer and reviewed three times every two weeks for accuratelandmark identification.When all the analyses were done, the results were subjected to T test usingthe SPSS program (Statistical Product and Service Solutions, USA). The levelof significance was set at0.05.Results:Part1:1Cephalometric analysis for Chinese adults with well-balance profiles bygenderThe male showed significantly smaller than the female in SE length(Steiner). The male showed significantly larger than the female in the items asfollows: Lower lip-E.plane (Ricketts); lower vertical height-depth ratio,upper-lip protrusion,lower-lip protrusion (Burstone); Soft tissue subnasale toH line (Holdaway); U1-SN(other). 2Cephalometric analysis for classâ…¡ by genderThe male showed significantly larger than the female in the items asfollows: T4-S,Ptm-ANS,T4-Pog (Wylie)3Comparation of cephalometric analysis between Chinese adults withwell-balance profiles and patients with Class â…¡The well-balance population showed significantly larger than the classâ…¡population in the items as follows: U1to L1angle (Steiner); Facial depth(Ricketts); FMIA (Tweed); Soft tissue facial angle, Nose prominence(Holdaway); APDI (MEAW).The well-balance population showed significantly smaller than the classâ…¡population in the items as follows: ANB,U1to NA length,U1to NA angle,L1to NB length,L1to NB angle,SL length,SE length (Steiner); Convexity,U1-APO disance,L1-APO disance,L1-APO degree,U6-PTV,Lowerlip-E.plane (Ricketts); Mandibular prognathism, U1prognathism, L1prognathism,EXL,ENL,LAFH (McNamara); Ptm-ANS, T4-S (Wylie); angleof convexity (Downs); IMPA (Tweed); facial convexity angle,upper-lipprotrusion, lower-lip protrusion, vertical lip-chin ratio, interlabial gap(Burstone); Soft tissue subnasale to H line,Lower lip to H line,Skeletalprofile convexity (Holdaway); ODI (MEAW).4Comparation of cephalometric analysis between Chinese adults and the otherethnic samplesThe Chinese showed significantly larger than Japanese in the items asfollows: SNB, SND, Pog to NB length,U1to L1angle (Steiner); Facial depth,Mandibular A (Ricketts); Y-axis (Downs); FMA,IMPA (Tweed); maxillaryprognathism,lower face-throat angle,lower vertical height-depth ratio,vertical lip-chin ratio,interlabial gap,maxillary incisor exposure (Burstone);Soft tissue subnasale to H line,Lower lip to H line,H angle,Upper lip sulcusdepth,Soft tissue chin thickness (Holdaway).The Chinese showed significantly smaller than Japanese in the items asfollows: ANB,L1to NB length,L1to NB angle,Occlusal pl. to SN angle,Go-Gn to SN angle,SE length (Steiner); Mandibular P,L.F.H,Convexity, U6-PTV,Lower lip-E.plane (Ricketts); angle of convexity (Downs); FMIA(Tweed); nasolabial angle, lower-lip protrusion (Burstone); Upper lipthickness,Upper lip strain measurement (Holdaway).The Chinese showed significantly larger than Whites in the items asfollows: U1to NA length,U1to NA angle,L1to NB length,L1to NB angle(Steiner); Mandibular A.,L1-APO disance,L1-APO degree,U6-PTV,Lowerlip-E.plane (Ricketts); Maxillary prognathism,Mandibular prognathism,L1prognathism (McNamara); angle of convexity, Y-axis (Downs); FMA,IMPA(Tweed); mandibular prognathism,lower face-throat angle,lower verticalheight-depth ratio,upper-lip protrusion,lower-lip protrusion (Burstone); Softtissue subnasale to H line,Lower lip to H line,H angle,Upper lip sulcusdepth,Soft tissue chin thickness (Holdaway); APDI (MEAW).The Chinese showed significantly smaller than Whites in the items asfollows: U1to L1angle,SL length,SE length (Steiner); Facial axis,Facialdepth (Ricketts); EXL,ENL,LAFH (McNamara); T4-S,T4-Pog (Wylie);FMIA (Tweed); facial convexity angle,vertical height ratio,nasolabial angle(Burstone); Soft tissue facial angle,Nose prominence,lower lip sulcus depth,Upper lip thickness,Upper lip strain measurement (Holdaway).5The correlational analysis in Ricketts: Y(Lower lip-E.plane)=0.447X1(U1-APO disance)+0.324X₂(Convexity)-3.253ï¼›Y(U1-APO disance)=0.107X1(L1to NB length)+0.987X₂(U1to NA length)+0.610X₃(ANB)-0.445X4(Pog to NB length)-0.097X5(SND)-0.037X₆(U1to NA angle)+7.461ï¼›Y(Convexity)=0.386X1(NA-PA)+0.088X2(L1to NBangle)-0.106X3(U1to NA length)-1.241.6The correlational analysis in Burstone: Y (facial convexity angle)=-0.251X1(nasolabial angle)+1.122X₂(lower-lip protrusion)-19.604ï¼›Y(nasolabial angle)=105.919-1.301X(U1to NA length)ï¼›Y(lower-lipprotrusion)=0.545X₁(L1to NB length)+0.043X2(SNA)-2.645.7The correlational analysis in Holdaway: Y(H angle)=1.118X1(soft tissuesubnasale to H line)-0.576X₂(soft tissue chin thickness)+0.848X3(skeletalprofile convexity)+0.443X₄(upper lip strain measurement)+11.998ï¼›Y (Skeletal profile convexity)=0.179X₁(NA-PA)-0.264X₂(NP-FH)+25.016ï¼›Y(Soft tissue subnasale to H line)=0.301X (L1to NB length)+6.133ï¼›Y(Upper lip strain measurement)=0.158X1(U1to NA angle)+0.079X2(SNB)-9.388Part2:1The soft-tissue measurement of3D CaMega scan system for Chinese adultswell-balance profiles by genderThe male showed significantly larger than the female in the items asfollows: n-Sn,tr-n,g-me,ls-li,Sn-sto,tr-g,g-Sn,Sn-me (Height); Ch-Ch,ft-ft,ex-ex,en-en,zy-zy,go-go,mz-mz (Width); Sn-n-si (Angle);pg-(go-go),pg-(t-t),n-(t-t),Sn-(t-t)(Distance); g-me/v-me,g-me/zy-zy(Craniofacial index); en-en, ex-ex, en-en/ex-ex, ex-Sn-ex, g-Sn/ex-ex,ex-ex/g-me (Eye); n-Sn,n-prn,Sn-prn,al-al,Sn-E,prn-(ls-pg),al-al/zy-z,al-al/Ch-Ch, al-al/n-Sn, al-al/g-me (Nose);t-t/v-me(Ear); Ch-Ch,ls-li,Sn-sto,sto-si,Sn-ls,ls-n-li,ls-n-pg (Lip); t-go,go-me,go-go (Mandible); mz-mz,zy-zy (zygomatic).The male showed significantly smaller than the female in the items asfollows: tr-me (Height); left (n-Sn-mz)/right(n-Sn-mz)(Angle); zy-zy/tr-me,go-go/g-me, ft-ft/tr-g, go-go/Sn-me (Craniofacial index);(pg-si)-FH,(me-go)-FH (Profile)(Mandible).2Comparison of the soft-tissue measurement between3D CaMega and CTsystem by genderThe CaMega showed significantly larger than CT for the male in the itemsas follows: tr-me,Sn-sto,g-Sn,Sn-me (Height); Ch-Ch (Width); Sn-me/g-me(Craniofacial index); ex-Sn-ex,ex-ex/zy-zy (Eye); Sn-prn,Sn-E,prn-(ls-pg)(Nose); Ch-Ch,Sn-sto (Lip).The CaMega showed significantly smaller than CT for the male in theitems as follows: eu-eu (Width); go-go/zy-zy,zy-zy/g-Sn,go-go/Sn-me(Craniofacial index); t-t (Ear); go-go/zy-zy (Mandible)(zygomatic).The CaMega showed significantly larger than CT for the female in theitems as follows: tr-n,g-me,tr-g,g-Sn,Sn-me (Height);(n-pg)-FH,t-pg-t (Angle); Sn-me/g-me (Craniofacial index);(n-pg)-FH(Profile); ex-Sn-ex,ex-ex/g-me (Eye); Sn-E,prn-(ls-pg),al-al/zy-zy (Nose); t-t (Ear); t-pg-t(Mandible).The CaMega showed significantly smaller than CT for the female in theitems as follows: tr-me (Height); eu-eu(Width); g-n-prn (Angle)(Profile);zy-zy/tr-me,go-go/g-me,go-go/zy-zy,zy-zy/g-Sn,go-go/Sn-me (Craniofacialindex); g-n-prn, al-al/g-me (Nose); go-go/zy-zy (Mandible)(zygomatic).Part3:1Smile measurements in Chinese adults with well-balance profile by gender:the male showed significantly larger than the female in the items asfollows:al-al(rest), al-al(smile), Sn-Ust(rest), Sn-Ust(smile), Chl-Chr(rest),pg-n (smile)-pg-n (rest),Li-Lll(smile).2Smile measurements in patients with class â…¡ by gender:The male showed significantly larger than the female in the items asfollows: al-al(rest), al-al(smile), Sn-Ust(rest), Sn-Ust(smile), Chl-Chr(rest)Li-Lll(smile); the male showed significantly smaller than the female in(Chl-Ust)+(Chl-Lst)/(Chr-Ust)+(Chr-Lst).3Comparation of smile measurement between Chinese adults withwell-balance profiles and patients with Class â…¡:The well-balance population showed significantly larger than the classâ…¡population for the male in the items as follows: al-al(rest), al-al(smile),(Chl-Ust)+(Chl-Lst)/(Chr-Ust)+(Chr-Lst).The well-balance population showed significantly smaller than the classâ…¡population for the male in the items as follows: Sn-Ust (smile)-Sn-Ust (rest),Cp-(L1-R1), Li-Ull(smile), Cp-(L1-R1)/Lst-(Llab-Rlab).The well-balance population showed significantly larger than the classâ…¡population for the female in the items as follows: al-al(rest),al-al(smile).The well-balance population showed significantly smaller than the classâ…¡population for the female in the items as follows: Chl-Chr(rest), Cp-(L1-R1),Ulgm-Ull(smile).Conclusions: 1Cephalometric norms in Chinese adults with well-balance profile of hannationality were estab-lished. Evaluate the esthetic characteristics ofsoft-tissue profile in Chinese adults with well-balance face. Find out thecorrelational relationship in cephalometric cephalometric measurments andregression relationship of between the relevant hard and soft tissue.23D craniofacial norms in Chinese adults with well-balance profile of hannationality were established. Find out the esthetic characteristics of soft-tissueprofile in Chinese adults with well-balance face with modern view.33D smile indexes in Chinese adults with well-balance profile of hannationality were estab-lished. Find out the esthetic characteristics of dynamicsmile in Chinese adults with well-balance face with modern view.