Evaluation of the Sealing Capability of Different Dental Implant Systems

Several implant-abutment connection designs are commercially available for different implant systems. These different implant-abutment connections, depending on the design and manufacturing precision, may lead to implant-abutment gaps of different magnitudes.

Objectives: The purpose of this study is to evaluate the sealing capability of the implant-abutment connection of different dental implants under cyclic loading.

Methods: Five Nobel Biocare(NB), Straumann, Intra-lock(IL), and Ankylos implants of ~4.5mm diameter with their respective abutments were provided by the manufacturers. A calibration curve was determined by placing Toluidine Blue(TB) increments of 0.1µL into 1.5 ml of distilled water and recording its absorbance in a spectrophotometer until reaching 0.7µL(set by the Ankylos internal connection volume). Following the establishment of a calibration curve, 0.7µL of TB was placed in each implant's connection, the abutment was adapted to the implant as recommended by the manufacturer, and placed in vials with 1.5ml of distilled water(the non-loaded condition). Spectrophotometric analysis was performed at 1,3,6,24,48,72,96, and 144 hours. Statistical analysis were performed by one-way ANOVA at a 95% level of significance.

Results: The calibration curve absorption is linear with respect to TB amount (Figure 1, left). The 95% absorbance confidence intervals are presented in Figure 2, right. 

Smaller amounts of TB in the liquid was observed for the IL, Straumann, and NB implants. However, while low TB levels were kept by IL implants, the Straumann and NB implants' release of TB increased as incubation time elapsed.

Conclusions: Different implant-abutment connection types resulted in different amounts of TB release as a function of time in-vitro. It should be noted that since the maximum amount of TB placed into the implants was close to the Ankylos internal connection volume, this system may have been disadvantaged during the testing. An experiment looking at TB release, normalized by the connection volume, should be investigated.