Effect of Implantoplasty on Roughness, Fatigue and Corrosion Behavior of Narrow Diameter Dental Implants

Implantoplasty (IP) is used in dental implants with peri-implantitis and aims to remove threads and polish rough surfaces in order to prevent bacterial colonization. As a result of this procedure, implant strength might be compromised. We tested 20 tapered screw-shaped Ti6Al4V dental implants with a simulated bone loss of 50%. Ten implants underwent IP and 10 served as controls. Surface topography (S-a, S-z, S-sk,S- and S-dr) was analyzed with a confocal optical microscope. Subsequently, a minimum of four series of cyclic loads were applied with a servo-hydraulic mechanical testing machine (5 x 10(6) cycles at 15 Hz, between a maximal nominal value-starting at 529 N in the IP group and 735 N in the control group-and 10% of that force). We recorded the number of cycles until failure and the type of failure. Implant failure was analyzed by visual inspection and scanning electron microscopy. Open circuit potential and potenctiodynamic tests were carried out with high precision potentiostat using Hank's solution at 37 degrees C to evaluate the effect of the implantoplasty on the corrosion resistance. Implantoplasty significantly reduced the surface topography values (median) and interquartile range (IQR); S-a from 1.76 (IQR = 0.11) to 0.49 (IQR = 0.16), S-z from 20.98 (IQR = 8.14) to 8.19 (IQR = 4.16), S-sk from 0.01 (IQR = 0.34) to -0.74 (IQR = 0.53) and S-dr from 18.20 (IQR = 2.26) to 2.67 (IQR = 0.87). The fatigue limits of the control and implantoplasty groups were 551 N and 529 N, respectively. The scanning electron micrographs showed fatigue striations indicating fatigue failure. Besides, the fractographic analysis revealed a typical brittle intergranular fracture mechanism. The infinite life range of the dental implants evaluated was largely above the threshold of usual chewing forces. Implantoplasty seems to render a fairly smooth surface and has a limited impact on fatigue resistance. In addition, implantoplasty produces a decrease in the corrosion resistance of the implant. Corrosion current density from 0.019 mu A/cm(2) for as-received to 0.069 mu A/cm(2) in the interface smooth-roughened dental implant. These places between the machining and the rough area of the implant are the most susceptible, with the appearance of pitting.

Automated summary

Implantoplasty is a technique used to treat peri-implantitis in dental implants by removing threads and polishing surfaces. This study found that Implantoplasty significantly reduces surface topography and has a limited impact on fatigue resistance, but it decreases the corrosion resistance of the implant.