The Orthodontic Treatment Of The Single Maxillary Incisor Absence Or Extraction

Objective:The destination of the article is to discuss the diagnosis, design and treatment effect of orthodontic treatment patterns of maxillary central incisors removal and closing the extraction space.Method:We select Shenyang Stomatological Hospital of Orthodontic patients admitted incisor missing or severely decayed,trauma patients in 3 male cases in 2012.The criteria of case selection:(1)Malocclusion of permanent dentition,aged 16 to25 years old;(2)The patients have passed the peak of the growth and they nearly have no potential growth;(3)The central incisor has crown fracture,root fracture or both crown and root fracture,severe decay leading decoloration and dedect even missing.severe periapical or periodontal disease;(4)The AngleI,II,III malocclusion with extraction with the cause of front teeth protrusion or crowding;(5)There is no obvious and severe bone problems;(6)The patients have subjective desire of orthodontic treament. According to model measurement analysis and X-ray measurement data analysis,combining patient’s request in initial treatment, we decided to adopt the straight wire appliance and extraction treatment with extracting the one maxillary central incisor and three first premolars.By the model measurements and X-ray measurement data analysis before and after treatment, we compare the angle change of the upper and lower incisors, the profile changes and hard tissues changes before and after treatment.Results:After a total of 26 months course of treatment,extraction space was used to lift crowding,the upper and lower teeth are neatly arranged, the upper lateral incisor substituted the missing central incisor,at the same time,the canine was used as lateral incisor.The relationship of bilateral molars, canines are neutral,and anterior teeth overbite and overjet are normal;midline aligned but was 1mm.on the left side.All the teeth achieved good occlusion.Soft tissue profile improved.We can conclude through skull radiographs of patients before and after treatment that:(1)changes of hard tissue:SNA and SNB had no changes. U1-SN,U1-NA,L1-MP and L1-NB decrease,U1-L1 increase.(2)changes of soft tissue: NLA, Z-plane increase, UL-EP, LL-EP, ULP,LLP decrese.Conclusion: Following the principle of individuation, according to guide the design of Bolton index, through unconventional extraction model treatment, we removed three premolars and the retained central incisors with little values,with effective anchorage control,it’s not only able to solve problems simultaneously existing that teeth do not adjust the amount of bone, but also to achieve the desired aesthetic purposes.