| Objectives: This study aimed to explore the influences of buccal corridoron smile esthetics by measuring and analyzing the buccal corridor value ofHan people, establish the ideal value, the minimum tolerable value and themaximum tolerable value of buccal corridors, compare the differences of theesthetic perception between orthodontists and laypersons, and between maleand female, and examine the differences of the buccal corridor value betweenmale and female. The purpose was to provide valuable references forexamination, diagnosis, treatment planning of the clinical orthodonticspatients.Methods: An adult male model and one adult female model wereselected from graduate students admitted in2011in Hebei Medical University.A general examination was done to select primary subjects from thosegraduate students. The criteria were as follows: Han nationality individuals atthe age of23to27, healthy, with normal growth, symmetrical left and rightface, balance among the facial thirds, coordination of profile and straight facetype. The criteria for selecting subjects included: good teeth alignment in botharches, neutral molar relationship, normal overbite and overjet of anteriorteeth, no history of orthodontic treatment, no periodontal disease or tempo--romandibular joint disease. Thus, thirty males and thirty females were choseas the primary subjects.With a CanonEOS40D digital camera, the selected60subjects werephotographed in a frontal pose smiling, with the head in a naturally relaxedposition, two eyes line paralleling to the ground plane so that his whole facewould be framed. All the photographs were taken by the author with the sameenvironment under the same light conditions with a CanonEOS40D digitalcamera. The camera was set to macro mode and was adjusted steady by a tripod. These subjects were seated in natural head position with a distance of160cm between the subjects and the camera and a distance of80cm betweenthe subjects and the background.Ten orthodontists and ten laypersons were selected. The criteria ofselecting orthodontists were over5-year working experience in the field oforthodontics. The ten laypersons included college teachers and leaders. Theesthetic value of each smile of the primary subjects was accomplished with avisual analog scale. The visual analog scale was100mm long. The “The leastattractive” smile was scored as “0”, while the “The most attractive” scoredwas as “100”. The esthetic scores ranged from0to100, with “0” as theminimum and “100” as the maximum esthetic values. Based on their ownesthetic perception, the ten orthodontists and the ten laypersons ranked eachsmile from “The least attractive” to “The most attractive”. In this way, one ofthe most attractive male and female face were selected as the model.Two intraoral photographs of patients who had completed theirorthodontic treatment were selected. Selection standards included: completedenture, normal dental morphology, teeth color bright luminosity, no cavities,no defect and no prosthetic history, good tooth alignment in both arches,normal spee curve, neutral molar relationship, front teeth combined withnormal overbite and overjet, arch orbicular-ovate, gum color and configurationbeing normal, no periodontal disease.An intraoral photograph and a smiling photograph were combined andmodified by Photoshop CS3for lip line, upper lip curvature, smile arc, smilesymmetry, occlusal frontal plane, gingival components and dental componentsas the original photo. This original photo was produced based on the followingcriteria: Teeth and lips were bilaterally symmetrical; Maxillary gum wereexposed to1.0mm; The lower lip could contact the incisal edges; Thecurvature of lower lip was coincided with that of the maxillary incisors andcanines, Maxillary occlusion plan was normal, with dental morphology, gumcolor and configuration being normal.Buccal corridors was altered digitally with slider technology of Adobe Flash CS4to obtain a continuous range of buccal corridors（0%-25%）. A flashwith a total of360frames,30seconds long, was produced. It was replayed atthe speed of12frames persecond.Esthetic smile was evaluated by the selected96orthodontists andlaypersons respectively.The selected orthodontists included48males and48females, with theirage ranging from29-56, and the mean age of35.1±7.2years. All of themhad a college education and more than3-year working experience in theclinical practice of orthodontics.The selected laypersons included48males and48females. They also hada college education, but they had no knowledge about orthodontics, nor didthey have color blindness or amblyopic diseases.The orthodontists and laypersons sat in front of a computer with adistance of50cm in between. They adjusted the buccal corridors withadjustable image technology that allowed the variable morph to appearcontinuously on a computer monitor, so that they could choose an ideal value,the minimum tolerable value and the maximum tolerable value of buccalcorridors.The statistical analysis of all the data were performed by SPSS13.0statistical program,0.05was selected as the standard.Results：1The raters were reliable (P＝0.467，P＞0.05).2The results of statistics describing for male models were as follows:The minimum tolerable, the ideal and the maximum tolerable buccalcorridors value of male orthodntist were4.20±0.51%，9.81±2.92%and14.93±2.73%.The minimum tolerable, the ideal and the maximum tolerable buccalcorridors value of female orthodontist were5.82±0.74%,9.70±2.78%and15.11±3.88%.The minimum tolerable, the ideal and the maximum tolerable buccalcorridors value of male laypersons were6.00±1.53%,9.23±1.53%and 14.87±4.52%.The minimum tolerable, the ideal and the maximum tolerable buccalcorridors value of female laypersons were3.63±1.53%,9.20±2.74%and15.31±2.88%.3The results of statistics describing for female models as follows:The minimum tolerable, the ideal and the maximum tolerable buccalcorridors value of male orthodontist were3.83±0.36%,12.11±2.15%and16.14±3.10%.The minimum tolerable, the ideal and the maximum tolerable buccalcorridors value of female orthodontist were4.00±1.03%,11.63±2.38%and15.50±4.60%.The minimum tolerable, the ideal and the maximum tolerable buccalcorridors value of male laypersons were4.08±1.24%,12.03±2.71%and14.92±3.13%.The minimum tolerable, the ideal and the maximum tolerable buccalcorridors value of female laypersons were3.91±0.38%,12.07±3.00%and15.30±3.16%.4The differentiation of the buccal corridors esthetics betweenorthodontists and laypersons:The orthodontists’ esthetics for the minimum tolerable, the ideal and themaximum tolerable buccal corridors value of the male model were5.00±0.17%,9.75±2.77%and15.00±2.84%, which was compared with thelaypersons (4.79±1.00%,9.20±3.08%and15.05±2.91%), there was nodifference between the two groups（P＞0.05）; The orthodontists’ esthetics forthe minimum tolerable, the ideal and the maximum tolerable buccal corridorsvalue of the female model were3.92±0.17%,11.87±2.77%and15.82±2.84%,which was compared with the laypersons （4.00±1.00%,12.05±3.08%and15.11±2.91%、）, there was no difference between the two groups（P＞0.05）.5The differentiation of buccal corridors esthetics between male ratersand female raters.The male raters’ esthetics for the minimum tolerable, the ideal and the maximum tolerable buccal corridors value of the male model were5.00±0.17%,9.75±2.77%and15.00±2.84%, which was compared with thefemale raters (4.79±1.00%,9.20±3.08%and15.05±2.91%), there was nodifference between the two groups（P＞0.05）; The male raters’ esthetics forthe minimum tolerable, the ideal and the maximum tolerable buccal corridorsvalue of the female model were3.92±0.17%,11.87±2.77%and15.82±2.84%,which was compared with the female raters（4.00±1.00%,12.05±3.08%and15.11±2.91%）, there was no difference between the two groups（P＞0.05）.6The differentiation of the vale of buccal corridors between the male andthe female model.For the male model, the buccal corridors value of the minimum tolerable,the ideal and the maximum tolerable of all the raters were4.90±0.76%,9.48±2.73%and15.03±3.74%. For the female model, the buccal corridorsvalue of the minimum tolerable, the ideal and the maximum tolerable of all theraters were3.95±1.03%,11.96±1.99%and15.47±3.01%. And there wasstatistically significant difference (P＜0.05)Conclusions:1The buccal corridors esthetic database of the Han adolescents wasestablished.2There was no difference between the buccal corridors esthetics oforthodontists and that of laypersons. There was no difference between thebuccal corridors esthetics of male and that of female raters.3The value of the ideal buccal corridors of male was smaller than thatof female. |
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