Brånemark Implant®

New
Finite Element Analysis at the Implant/Bone Interface for One-Piece vs Multi-Unit Implant Systems

An Auger Spectroscopic Analysis of Dental Implant Surface Contamination
Examination of the Implant-Abutment Interface After Fatigue Testing

Abstract: The recent introduction of implant systems that combine the implant and the abutment as one unit has prompted the question of whether or not these new systems result in different stresses at the bone to implant interface when compared with the multi-unit implant systems. This objective of this study was to measure the stress between the implant and the bone at specific location for a one-piece implant compared to a multi-unit implant system when subjected to an off-axis vertical force using finite element analysis. The Brånemark Mark III implant, CeraOne abutment and the Unigrip screw were model for finite element analysis using HyperMesh® software. Similarly, the assembled implant structure was modeled as a one-piece unit. A finite element analysis was performed on both models subjected to a vertical off-axis load of 300 Newtons using ABAQUS® program. The stress measured within the cortical bone adjacent to the uppermost threads of both implant systems demonstrated the highest stress values. Stress measured for the one-piece implant was twice that of the multi-unit implant complex.
Conclusions: The one-piece implant unit demonstrated a greater stress at the bone to implant interface than the multi-unit implant system. The multi-unit implant system demonstrated a stress distribution pattern that was dramatically different than the one-piece implant when subjected to a vertical off-axis load.

Abstract: A key factor in osseointegration of titanium implants has been attributed to the presence of surface contamination in the “as delivered state.” The purpose of this study was to examine the surface of implants from six major implant systems and to assess the presence, type and amount of surface contaminants following manufacturing. Five implant obtained from different manufacturing lots for the following systems formed the experimental population: 1) 3I, 2) Impla-Med, 3) Brånemark, 4) Steri-Oss, 5) Lifecore – Restore, and 6) Swede-Vent. Four sites 5 x 5 microns in area were surveyed from the flat bottom on each implant using Auger electron spectroscopy (AES). The elements present in the Auger spectra for each implant system were identified and the surface area of the contaminants measured. Contaminating elements included carbon, calcium, sulfur, phosphorus, silicon, boron, chloride, potassium, fluorine, silver, cobalt, aluminum, antimony, vanadium, nickel and iron. The Brånemark and Steri-Oss implants exhibited the highest average surface concentrations of titanium (31.7 and 32% respectively), and oxygen (31.2 and 34.9% respectively). These implant systems also demonstrated the lowest amounts of total contaminants (16.7 and 16.2%). The Lifecore – Restore implants had the highest amount of total contaminants (29.6%) and the lowest average concentration of titanium (16.8% and oxygen (22.7%). Swede-Vent implants had high amounts of surface fluorine (7.1%), while the Steri-Oss implants had high amounts of silicon (5.6%).
Conclusions: Significant differences were found between the implant systems evaluated for most elements (P>0.05) with repeated measures ANOVA and Scheffé’s S-test.

Abstract: This study was designed to examine potential differences in de-torque values of abutment screws following fatigue testing when the dimensions between implant hexagons and abutment hexagons are altered or the implant hexagonal shape is eliminated. Three experimental Nobel Biocare implants (n=10) were machined with the conventional hexagonal (R), modified hexagonal (M) and circular (N) platform geometry. Thirty Procera® custom abutments with a 25° angulated loading platform were manufactured. Abutments were retained with Unigrip® (Nobel Biocare) abutment screws tightened to 32 N/cm. Vertical scribes across the implant/abutment interface allowed x-y axis evaluation. An Instron carousel-type fatigue testing device delivered dynamic loading between 20 and 200 N for 5,000,000 cycles, or approximately equivalent to 5 years in-vivo mastication through a piston to the abutment platform. Microscopic and radiographic examination of the implant/abutment specimens was completed. The abutment screws were removed and the de-torque values recorded. Bearing surfaces were examined microscopically. No abutment looseness or x- or y-axis displacements at the implant/abutment interface were noted. Radiographic examination demonstrated no indication of screw bending or displacement. The mean de-torque values for R, M and N were 14.40 N/cm, 14.70 N/cm and 16.40 N/cm respectively.
Conclusions: The analysis of variance demonstrated significant differences in the mean de-torque values between only the conventional hexagonal design R and the circular hexagonal design N (P=0.03). Increasing the distance between the implant external hexagon geometry and the internal hexagon geometry of an abutment did not produce a significant effect on the de-torque values of the abutment screw after 5,000,000 cycles in fatigue testing for the implant/abutment specimens evaluated.