Determination of a Proper Covering Material for Fixture-Abutment Microleakage Evaluation Using Radiotracers and Gamma-Counter; A Pilot Study

Radioisotopes adhere to any surface in which they come in contact. Covering the sample surface with a suitable material prior to submersion and isolation of the material before counting make it possible to evaluate the penetrating radioisotopes within the interfacial area. The aim of this study was to determine a suitable material to cover implant and abutment in evaluation of microleakage in implant-abutment interface using radiotracers and gamma counter.

In this in vitro study, 46 samples were selected and divided into two groups. The first group consisted of implant samples covered with putty, nail polish and putty-super glue with 1mm distance from the interface. The second group included non-implant samples covered with putty, autopolymerizing acrylic resin, and nail polish. This group was used for evaluation of adherence levels of the radioisotopes. Microleakage test was performed with thallium-201 and gamma counting in three phases: 1) after removing samples from thallium solution, 2) after washout of samples, and 3) after removing covering materials. In order to compare penetration of radioisotopes within the samples analysis of co-variance was carried out.

There were statistically significant differences between three phases of gamma counting and between samples in different implant groups. Microleakage of implant-putty-glue was significantly less than that of implant-putty (217343.40± 86007.926). Similarly, implant-putty showed a significantly less microleakage than implant- nail polish. (313247.20±67933.031).

The best material among the ones considered in this study turned to be putty sealed by super glue. Contrarily, nail polish was not considered suitable due to increased microleakage.