Application And Case Report Of Sectioned Resistance Welding In Immediate Implant Restoration

Objective:Resistance welding is often used to make implant-supported immediate restoration,which can obtain good passive fitting.It is difficult to weld in the mouth when there are multiple implants,and the micro-deformation of titanium wire is easy to produce stress on the implant after welding.This study intends to improve the existing clinical treatment process of immediate restoration by intraoral welding:(1)to explore the feasibility of sectioned welding when there are multiple implants;(2)to put forward a new process to reduce the difficulty of welding and ensure passive fit when fabricating immediate restoration by resistance welding technique,so as to provide reference for clinical application.Methods:80 temporary titanium copings were randomly divided into 3 groups A,B and C,with 8 samples in each group.2 temporary copings were welded with a section of titanium wire in group A,4 temporary copings were welded in pairwise in group B,and4 temporary copings were welded with whole titanium wire in group C.Four copings in groups B and C with 15 mm distance between each copings were arranged in trapezoid,which was 30° to the horizontal plane.Each coping was fixed on the multi-abutment analog with 15 Ncm.1,A vertical downward force is implemented at the midpoint between the two welded joints of the titanium wire until either of the welded joints is broken,which is to test the compressive performance.2,Fatigue property is tested by loading 2.5×10~5 times under 10 Hz sine wave load.3,Patients with immediate implant restoration indications were selected from February 2020 to December 2020 in the Department of Implant,Stomatological Hospital.The process of immediate restoration with sectioned resistance welding was applied and improved.The modified clinical process of resistance welding was introduced through the report of 3 typical cases.Results:1,The pressure value of group C(640.41±241.34 N)was significantly higher than that of group A(347.47±14.05 N)and group B(355.52±24.95 N),(P<0.05 N),but there was no significant difference between group A and group B(P=0.746).2,There was no significant difference in fatigue performance between group A(100±16.32 N),group B(120±16.32 N)and group C(125±10.00 N)(P=0.083).3,Sectioned titanium wirewelding combined with a variety of passive fit evaluation methods ensures accurately passive fitting of the immediate prosthesis.With the improved process,the chair time is shortened,and the discomfort of the patients is reduced;there is no buccal and lingual muscle barrier in the extra oral welding,and the operation without block is beneficial to the welding;patients are satisfied with the appearance and pronunciation when wearing denture,and the complications of implant restoration have not been observed.However,the process of transferring occlusion still takes a long time,and the gingival recession after operation makes it difficult to maintain oral hygiene,which needs to be solved in the future.Conclusion:Sectioned resistance welding will not reduce the fatigue strength of titanium framework.The modified resistance welding process reduces the difficulty of titanium wire welding and guarantees the accurate passive fit of immediate restoration.The problems of occlusion transferring and hygienic maintenance after gingival recession need to be further solved.