| Skeletal class Ill is a normal malocclusion,the main characters of severe adults’ skeletal class Ill are the imbalance between maxilla and mandible in sagittal direction,deficiency of maxilla,protrusion of mandible or both of them;the compensatory labial inclination of upper incisors and lingual inclination of lower incisors;and the concave profile.For severe adults’ skeletal class Ill,orthodontic treatment only can not achieve the ideal result,and the orthodontic-orthognathic treatment is the best choice to get a good occlusion and a harmony profile.The traditional surgical plan combines the values about pre-surgical profile of X-ray with the orthognathic surgeons’ clinical experience,but the references are complex,it is usually difficult to consider both sides.In 2000 Andrews published the Six Elements of Oral Facial Harmony,first combined the external and internal landmarks together,making it easy to product the surgical plans suitable for individuals,.Because the concise of the references the Six Elements needed,make it convenient to work out a more accurate surgical plan.For adults with skeletal class Ill,concise surgical plans can improve the clinicians’ confidence,achieve a better postsurgical profile the adults wishes,and establish a solid relationship between doctors and patients.ObjectiveThe aim of our study is to research the difference between traditional orthognathic plan and Andrews’ Six Elements’ plan treating severe skeletal class Ill patients respectively,and find out the public’ preferred surgical plans.Method Experiment I:Select 150 Chinese Han people with individual normal occlusion(74 males and 76 females),according to gender,every patient was captured lateral cephalometric radiographs and profile photos,measure the relative lengths and angles the Andrews’ Six Elements asked by SPSS 19.0 and find out if there was difference between males and females by Independent-Sample t-test after using NemoCeph NX software to overlap lateral cephalometric radiographs and profile photos together,Experiment Ⅱ:The samples in this experiment were the same to Experiment I and divided the subjects into two groups according to gender,measured the inclination of forehead,and analysed these figures by SPSS19.0 to conclude the means of inclination of forehead,find out whether there is difference about the forehead’ inclination between the two genders.and research the GALL Line suitable to Chinese Han people in sagittal direction,find out the relationship between the GALL Line and glabella in sagittal direction in Chinese Han with individual normal occlusion.Experiment Ⅲ:Patients whose pre-surgeryorthodontic treatment has been completed and prepared to undergo orthognathic surgery were included(12 males and 13 females),used the decompensated lateral cephalometric radiographs to simulate the post-surgical black and white silhouettes respectively in accordance with traditional surgical plan and Andrews’ Six Elements’ plan by PS 5.0,and rated the 24 groups silhouettes by professions and laypeople,used SPSS 19.0 to measure the means of every silhouette’ scores and compared each group’ scores by paired-t test research if there was difference about appreciation of the beauty between profession and laypeople and find out which surgical plan is better to simulate a more harmony profile.Result: 1.The profiles of Chinese Han with individual normal occlusion met the requirements of Andrews’ Six Elements about the profile:(1)The FFA of maxillary central incisors fall on GALL Line,no more than ±1mm,and there was no significant difference between two genders;(2)There was no significance among the medial frontal facial height、the lower frontal facial height and the posterior facial height;(3)The distance from L1 FA to Me is half of the distance from Po to Go;(4)Po falls on the Will line,no more than ±1mm,and there was no significant difference between males and females.2.According to the good-looking people of Chinese Han,our study concluded that:(1)The inclination of forehead among these people was averagely more than 7,no matter males or females,but the forehead’ inclination of males was a little sharper than females;(2)About 93.4% males’ GALL Line passed through glabella,and 95.9% females’ GALL Line passed through glabella,which indicated that most of good-looking people’ GALL Line passed through glabella.3.Simulated the post-surgical silhouettes using traditional orthognathic plan and Andrews’ Six Elements’ plan respectively and we could conclude that:(1)Both professions and laypeople preferred the silhouettes simulated by Andrews’ Six Elements,and the scores between the two surgical plans had significant difference;(2)There was significant difference between the two raters,no matter in traditional orthognathic plans or Andrews’ Six Elements’ plan.Conclusion:Our study has shown that the profile of Chinese Han beauty meet the requirements of Andrews’ Six Elements,and the inclination of forehead is steep,so that the GALL line in the sagittal direction mostly lies on the glabella,but the difference of forehead’ inclination between male and female is small.For adult patients with skeletal Class III malocclusion,compared with the traditional operation plan,two raters prefer the silhouettes simulated by Andrews Six Elements’ plan,and professional group preferred Andrews Six Elements’ plan.The traditional orthognathic plan is more based on the dental occlusion and the normal range of profile hard tissue combined with the clinical experience of surgeons,and there was little attention about soft tissue,however Andrews six elements combines dentition with maxillofacial soft and hare tissue together as a reference,which can make a more accurate surgical plan. |
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