The Clinical Application Study Of Indirect Bonding Technique In Labial Orthotherapy

Background and objectivesThe accurate position of the bracket is a key factor to obtain the ideal treatment results.In particular,with the universal application of the straight wire appliance was used nowadays.The traditional direct bonding technique is used to bond brackets which is not possible to achieve accurate position of brackets,especially for posterior segment brackets.This makes it possible for orthodontists to compensate for the uneven alignment of the teeth by making various compensation curves on the top of the arch wire at the later stage of orthodontic treatment,and will cause the teeth to move back and forth,increas ing the treatment time and influencing the treatment results.The appearance of indirect bonding technique makes it possible to position the bracket precisely,it refers to that the brackets and buccal tubes were bonded to the plaster model in advance,and then the transfer tray is used to transfer the brackets to the mouth.But under the restrictions of dental laboratory time,technical sensitivity and high cost,this technique is mainly used in lingual orthotherapy,while less used in labial orthotherapy.Therefore,it is very significant to evaluate reliability of indirect bonding technique in labial orthotherapy,and to find out the sensitivity reason in this technique.Thus in order to provide reference for orthodontists and promote the popularization and application of indirect bonding technique in clinical orthodontics.This research goes through clinical experiment and in vitro experiment to analyze indirect bonding technique and direct bonding technique of the total bonding time,chair-side time,bond failure,shear bond strength,the accurate of the brackets in indirect bonding technique.Thus in order to prove whether the indirect bonding technique is superior to direct bonding technique in labial orthotherapy,and whether indirect bonding technique is reliable.At the same time,Lean Six Sigma method is used to improve and optimize the indirect bonding technique process.The purpose of this study is to provide a theoretical basis for the application of indirect bonding technique in l abial orthotherapy and to choose a simple and reliable bonding technique for orthodontists.Materials and methods1 Clinical studiesSelected 60 patients who were treated with Straight Arch wire Techniques in orthodontic Department of Daping Hospital of Third Military Medical University during July 2015 to August 2016.Among them,27 of patients are males and the other 33 are females.The average age was 19.4 with range of 14~30 years.Angle Class I malocclusion in 25 cases,Angle class II malocclusion in 35 cases and they are all non extraction cases.60 patients were randomly divided into Group A and Group B(n =60),including Group A(n = 30)and Group B(n = 30),patients in group A were bonded with direct bonding technique,and group B was bonded with indirect bonding technique;Each patient was bonded with 20 brackets and 4 buccal tubes.A total of 600 brackets were bonded to each group of the patients,with a total of 120 buccal tubes.1.1 The two groups were bonded brackets with the use of the four-handed technique.Recording each patient's Chair-side time for Group A and B,and dental laboratory time for Group B respectively;1.2 Recording the number of bracket bond failures and tooth position for each patient in Group A and Group B,including the number of bracket bond failures during bonding.Keep recording for 6 months continuously;1.3 Randomly selecting 5 patients which were bonded with ceramic brackets from Group B to collect brackets data from scanning plaster model and intraoral with 3D intraoral scanning technique and then comparing and analyzing the differences between the data of two groups by using 3-Shape special software;1.4 Using application of DMAIC process analysis technology in Lean Six Sigma method to improve and optimize the whole process of the indirect bonding technique;2.In vitro experimentCollected 40 in-vitro premolars which were extracted for orthodontic reason,dental fluorosis and tetracycline teeth were excluded.The teeth must be no caries,no filling,no crack.And the in-vitro premolars were put into 9% normal saline and were kept in room temperature preservation.The 40 in-vitro premolars were randomly divided into Group A and Group B(n = 40)with each group of 20 samples.In group A,the brackets were bonded with direct bonding technique,and Group B were bonded with indirect bonding technique;The shear bond strength of each sample was tested by universal mechanical testing machine,and the adhesive remnant index(ARI)was analyzed by optical microscope.Results1 Clinical studies1.1 The average Chair-side time of Group A was 30.9�2.3min,and the average Chair-side time of Group B was 15.4�1.7min(P <0.05);In group A,the time of single bracket was 2.58�0.19 min,and the time of single bracket was 1.29�0.14 min in group B(P < 0.05);In Group B,the average dental laboratory time was 30.8 �2.7min,and the average total bonding time was 46.27�3.27min(P < 0.05);1.2 The total bond failure rate of bracket in Group A was 9.7%,in Group B was 8.3%,(P > 0.05);The bond failure rate of buccal tube in Group A was 3.2%,and 5.6% in Group B,(P <0.05);The bond failure rate of bracket in Group A was 6.5%,and 2.8% in Group B,(P <0.05);1.3 The position data of the A2?A4?A5?A6?B1?B2?B3?B5?C1?C3?C4?C6?D1?D2?D3?D6 is almost the same before and after the transferring,(P > 0.05),While the position data of the A1-incisal,A3-distal,palatal side,B4-incisal,B6-palatal side,C2-incisal,C5-incisal,D4-incisal,D5-cervical margin were slightly different,P value was slightly less than 0.05,and the difference was less than 0.5mm;1.4 The improved indirect bonding process improved the work efficiency,reduced dental laboratory time and the Chair-side time,ensured the accuracy and quality of bonding and saves bonding cost;while reducing the opening time of patients,improve d patient comfort level;2 In vitro experimentThe average shear bond strength of Group A and Group B was 12.06�7.16 Mpa and 22.98�13.07 Mpa,respectively(P < 0.05).The mean ARI index of Group A and Group B were 1.90 �1.02 and 1.55 �0.89,respectively(P > 0.05);Conclusion1.The advantages of indirect bonding technique is that it can significantly reduce the chair-side time,although the total bonding time is greater than using the direct bonding technique,but flexible dental laboratory time allows doctors to calm the patient.2.There was no significant difference between the direct bonding technique and indirect bonding technique in the bond failure rate,but the buccal tube bond failure rate was significantly higher than that of using direct bonding technique,while the bracket bond failure rate was significantly lower than that of using direct bonding technique.3.The application of double layer silicone rubber transfer tray in indirect bonding technology has high transfer accuracy,which can meet the clinical requirements of orthodontics.4.Using the application of Lean Six Sigma method to improve and optimize the indirect bonding process,can significantly improve the bond quality,improve the bonding efficiency and reduce the cost of bonding and improve patient satisfaction.5.The shear bond strength of indirect bonding technique and direct bonding technique can meet the clinical needs of orthodontics,shear bond strength in indirect bonding technique was significantly higher than that of direct bonding technique;Two kinds of technique of ARI index were higher,no statistically significant difference.