| ObjectiveThis master's thesis is devoted to the study of the clinic effects of a new type of root torquing auxiliary arch in coordination with the straight wire appliance under the assistance of micro-implant anchorage;meanwhile it attempts to build a three-dimensionalal model with finite elements,and discusses the most optimistic anchorage together with the torque control that treats the linguoclination of the upper incisor teeth.with In expectation,it may provide on the one hand bio-mechanical implications to clinic treatments,on the other more dependable data that speaks in favor of the application of this new type of root torquing auxiliary arch.Methods1.Analyses on the ways of root-controlling over the upper incisor teeth differing in anchorage and manners of torque powering with three-dimensional finite elements analysis.(1)the forming of three-dimensional finite elements model of the torque control system by the upper incisor.This project first obtain data from CBCT scanning on a few individual normal jaw,which is then imported into the Mimics system to conduct three-dimensional refiguring on the jaws.With the reverse engineering system Geomagic which helps remove noisy points,modify fringe figuration and automatically optimize curve,individual solid model in smooth line is generated.Next,it establishes the upper jaw-teeth group-bracket-arch wire-root torquing auxiliary arch-micro-implant geometric model after assembling those individual models with the Soliworks.(2)The three-dimensional finite elements analyses on the torque control system of the upper incisor teeth.In this part of research,this project simulates the two situations of,fir st,the process in which the inter-teeth gaps are shutting,and second,when they come to completely closure.Also,with different corresponding anchorage,by contrasting the effects when the upper incisor area is applied respectively with either wire torque,root torquing auxiliary arch alone,or then the two together,this project calculates the instant displacement,the distribution of periodontal stress and its value.In light of the progression of corrective treatment,use of anchorage,manners of torque applications,we classify our data into four major groups,and 14 working conditions:Group One: during the progress in which the inter-teeth gap is closing,it takes the first upper molar as the anchorage to hold inward the front teeth.1A: wire torque1B: root torquing auxiliary arch1C: wire torque unit with root torquing auxiliary arch1D: no adding of torqueGroup Two: during the progress in which the inter-teeth gap is closing,it takes the micro-implant as the anchorage to hold inward the front teeth.2A: wire torque2B: root torquing auxiliary arch2C: wire torque unit with root torquing auxiliary arch2D: no adding of torqueGroup Three: After the inter-teeth gap come to a full enclosure,it uses the binding weir to inflexibly hold fast the main wire with the guiding hook and the same-side first molar.3A: wire torque3B: root torquing auxiliary arch3C: wire torque unit with root torquing auxiliary archGroup Four: After the inter-teeth gap come to a full enclosure,it uses the binding weir to inflexibly hold fast the main wire with the pulling hook and the same-side upper jaw micro-implant.4A: wire torque4B: root torquing auxiliary arch4C: wire torque unit with root torquing auxiliary archIn each group,the value of traction is set as 115 g,the value of wire torque as 4.5 N·mm,the value of root torquing auxiliary arch traction as 1.5 N·mm.2.The clinic effects of the new type of root torquing auxiliary archWe collect 25 cases that reflects the emergence of the erection or even the linguoclination of the upper incisor teeth on patients who were receiving the orthodontic treatment with straight wire appliance,after enclosing the inter-teeth clearance.Seeing to situations as such,this study applies the new type of root torquing auxiliary arch to the upper incisor teeth.To observe the progression,we perform skull profile x-ray to these three stages: pre-treatment,treatment after 3 months,after-treatment and analyze the changes in following parameters: ? Max1-SN?? Max1-NA?? SNA,the distance between root apex and SN vertical line,the distance between incisal margin and SN vertical line.The results are input to the SPSS system for statistical analyses.It also tracks down the patients' phases of treatment,and observes whether there emerged any syndromes such as the root apical inflammatory,under-ingestion of the root with the aid of CBCT scanning before and after our operations.Results:1.Analyses on the ways of root-controlling over the upper incisor teeth differing in anchorage and manners of torque powering with three-dimensional finite elements analysis.? the direction and value of teeth's instant displacementGroup One: during the progress in which the inter-teeth gap is closing,when it takes the upper first molar teeth as the anchorage,the trend of teeth's motion of the four groups are: the upper incisor teeth are pulled toward the tongue by traction,the incisal tip moves more than the root apex.The values of the incisal tip-root apex motion difference of the four groups follow: 1D>1A>1B>1C;the values of incisal tip motion also follow: 1D>1A>1B>1C;root motion follows: 1D the smallest,1A,1B and 1C are basically identical.Group Two: during the progress in which the inter-teeth gap is closing,when it takes the micro implant as the anchorage,the trend of teeth's motion of the four groups is similar to those in the first group: the upper incisor teeth are pulled toward the tongue by traction,the incisal tip moves more than the root apex.The values of the incisal tip-root apex motion difference of the four groups follow 2D>2A>2B>2C,the values of incisal tip motion: 2D>2A>2B>2C;the root apex motion: 2A the most obvious,2D the smallest,2B and 2C are basically identical.Group Three: After the inter-teeth gap come to a full enclosure,the pulling hook and the same-side first molar binded,the trend of incisor teeth motions follow: the dental crown and the first half above root move toward the lip side,half of the root tip moves toward the tongue,the incisal tip's lip-ward motion outruns root-tip motion.Under the effects of different torques,the values of incisor teeth motion follows: 3C?3B?3A.Group Four: After the inter-teeth gap come to a full enclosure,the pulling hook and the same-side implant binded,the trend of incisor teeth motions follow: 1/3 incisal tip of the dental crown moves to the upper front toward the lip,the neck of teeth and root moves toward tongue,the tongue-ward motion by the root outruns the neck.The values of the three groups follow: 4C?4B?4A.(2)the stress distribution of parodontiumGroup One: the parodontium stress of 1D concentrates on the 1/3 part of the side root of lip,on the 2/3 part of the tongue side root.That of 1A concentrates on the 1/2 of part the neck of the lip side,also on the 1/2 part of root of the tongue side,that of 1B concentrates on the 1/3 part of the fringe of the lip side and the root of tongue side,that of 1C on the 1/3 part of the fringe of the lip side and the root of tongue side,but is smaller than 1B in ra nge.Group Two: similar to Group one,the parodontium stress of 2D concentrates on the 1/3 part of the side root of lip and on the 2/3 part of the tongue side root.That of 2A concentrates on the 1/2 of part the neck of the lip side and also on the 1/2 par t of root of the tongue side,that of 2B on the 1/3 part of the fringe of the lip side and the root of tongue side,that of 2C on the 1/3 part of the fringe of the lip side and the root of tongue side,but is smaller than 2B in range.Group Three: the distribution pattern of the three sub-groups are identical,and relatively balanced.The parodontium stress on 1/3 part of the neck up to the root of the lip is more obvious,with the maximum showing up at the neck of the lip side,the value of parodontium stress are all smaller than 26 KPa,in the groups of 3B and 3C,the value of parodontium stress on the brim of the neck the lip and tongue side is above 26 KPa,that of other parts are smaller than 26 KPa.Group Four: the distribution pattern of the three sub-groups are identical,and relatively balanced.The parodontium stress on the neck of the lip side is more obvious,its values in 4A?4B?4C are all smaller than 26 KPa.2.Clinic effects:After a treatment of 5.9±0.9 months on average of the patients,their Max1-SN angle,Max1-NA angle grow,SN sector-root apex shrinks,SN vertical line-incisal margin grow,such difference is statistically meaningful,(P<0.05).SNA angle encounters no obvious variation after treatment,which however is statistically insignificant,(P>0.05).Conclusions:1.During the progress in which the inter-teeth gap is closing,affected by traction,the upper incisor teeth generates in-ward movement,which is accompanied by the movement of the crown toward the tongue.Tongue-ward movement can be relieved with the torque pull by wire torque or root torquing auxiliary arch but cannot be avoided.2.The use of micro implant can stabilize the primary wire,which leads the upper incisor teeth to generate the ideal result: the holistic tongue-ward movement.3.In controlling the root of tongue-ward movement,the new type of root torquing auxiliary arch is better than wire torque,while root torquing auxiliary arch works together with the wire touque is the most optical.4.When torque pull is imposed on the upper incisor teeth,stress concentrates primarily on the parodontium covering the neck of the lip,tongue side;When torque pull is imposed on the upper incisor teeth during the progress in which the inter-teeth gap is closing,the value of stress outruns the maximum safe range;when torque pull is imposed after the inter-teeth gap come to a full enclosure,the parodontium stress maintains in the safe range.5.The new type of root torquing auxiliary arch is effective in controlling the control over the upper incisor teeth torque. |
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