A Contrast Study On Micro Leakage Of Bacteria And Biomechanics Between Stock Abutments And Custom Dental Implant Abutments Of Bicon Implants

Background: With the development of technology,the implant denture is becoming the best treatment for the dentition defect and dentition missing.It is largely addressed the implant need of a considerable number of patients with deficient bone that the short implants which represented by Bicon implants.It is the important assembly unit of the abutment that connecting to the implants and the restorations,and how to choose the appropriate abutment which is related to the function and aesthetic effect of implant denture.Although with a wide ranges,the stock abutments are in a single form,and it is very difficult to give consideration to both the function and the aesthetics for patients,so it must choose the custom abutments in some cases.It is a common complication of the peri-implantitis after the implants were inserted,which may cause the inflammation of soft tissue,progressive absorption of bone,and the failure of implants in severe cases.There are a lot of factors causing peri-implantitis.In recent years,scholars have focused attention on the micro leakage caused by the microgap between the implant and the abutment,and take for that the peri-implantitis might be related to the micro leakage.Objectives: In this study,(1)escherichia coli(ATCC25922)was used as the micro leakage detection markers to compare the differences of bacteria sealing capacity between stock abutments and custom dental implant abutments of Bicon implants.(2)The clamping force between custom abutments,stock abutments and Bicon implants were valuated through biomechanical test.Some experimental evidence and theoretical guidance were provided for the clinical application of the custom abutments of Bicon implants by above-mentioned experiments of comparing the difference between the stock abutments and the custom abutments of Bicon implants.Material and Methods:(1)In the sterile environment,10 Bicon implants(3.0*6.0mm with well diameter 2.0mm)were randomly divided into A,B two groups,No.1-5 were contained in group A,No.6-10 were contained in group B.3μl the escherichia coli liquid were dropt in the ten implant sockets,then the stock abutments were assembled in group A and the custom abutments were assembled in group B.The samples were put in the sterile petri dishes(6 cm)respectively,then 12 ml sterile TSB culture medium were added in and were put in the 37℃ incubator.3ml TBS culture medium were exchanged every 24 hours.10μl TBS culture medium were dropt on blood AGAR plates(10 cm)and were coated evenly by the bacteria inoculated sticks when after cultured 6h,24 h,48h,72 h and 168 h.The escherichia coli colonies were calculated when after cultured 24 h in the 37℃ incubator.(2)10 Bicon implants(3.0mm*6.0mm with well diameter 2.0mm)were randomly divided into A and B group.The stock abutments were assembled in group A and the custom abutments were assembled in group B.After embedded by resin,tensile test and torsion test were performed respectively for the 10 specimens by the micro tensile and torsion testing machine MTS Bionix 858,and the test data were recorded.Results:(1)No escherichia coli colony was found in No.1,3,4,5 specimen in group A at any time point.A small amount of colony were found for the No.2specimen after cultured 24 h.The escherichia coli colony was found in every specimen of group B at every time point,and the number of colonies increased obviously as time went by.The average colony at five time points in Group A were 0,1.6 ± 3.58,3.40 ± 7.60,4.64 ± 10.29 and 9.6 ± 21.47(cfu)respectively.The average colony of the five time points in Group B were 57.6± 10.09,83.4 ± 10.78,235.4 ± 32.46,4667 ± 40.75 and 924.8 ±11.39(cfu)respectively.There were statistical significant difference between the number of colony in Group A and that of in Group B(p<0.05).(2)In the aspect of biomechanics,The average of the maximal pulling-out force in group A was 171.96 ± 9.64(N),and the average of in Group B was 97.77 ± 5.66(N).The average of the maximal torque of Group A is 18.79 ± 0.84(N·cm)and the average of the group B is 11.79 ± 0.98(N·cm).There were statistical significant difference between Group A and Group B both on the maximal pulling-out force and the maximal torque(p<0.05).Conclusion:(1)The bacteria sealing capacity of the stock abutments of Bicon implants(with well diameter 2.0mm)were better and superior to that of custom dental impant abutments.(2)The clamping force of stock abutment of Bicon 7implants(with well diameter 2.0mm)were better and superior to that of the custom dental implant abutment.