Determination of fluid leakages in the different screw-retained implant-abutment connections in a mechanical artificial mouth

Abstract

This study shows the potential risk of microfiltration between two different types of implant-abutment connections screwed at 45 Ncm: external and internal. For the first time the use of a mechanical artificial mouth is used with the values (compression and torsion loads with a frequency of 2 Hz) of the human chewing. The mechanical tests were performed with an artificial saliva at 37 oC. The microgap in the connection was measured by an Image Analysis software incorporated in a high resolution scanning electron microscopy. Implant connections were filled with methylene blue by using self-adjustable precision pipettes and the quantity of leakage was determined by high sensitivity spectometry. We showed that the internal connection has lower microgaps compared to the external ones and these microgaps increased with the number of mechanical cycles. The leakage of methylene blue was higher when the external connection was performed. Microgaps and the influence of the mechanical loads are very important for the long-term behavior avoiding the bacteria colonization in the dental implants. These aspects should be known by the implantologists.

Study of the Effect of GapSeal on Microgap and Microleakage in Internal Hex Connection After Cyclic Loading

“…According to various studies, cyclic loadings increase the microgap size at the implant-abutment interface, especially in implants with external hexagonal connections. (9,(20)(21)(22) In the present study, the samples underwent cyclic loading to simulate clinical conditions, and the findings of the present study, indicating the presence of microleakage in the space present at the abutment-implant interface, are in line with previous studies. The results of studies that used bacteria to measure microleakage are more consistent with reality compared to the use of methylene blue.…”

“…(6) In 2015, Martin-Gili et al investigated fluid leakage in external and internal connections of screw abutments. (9) The size of microgap in the cited study was 2.34 µm in the internal hex connection after cyclic loading and 4.01 µm in the external hex connections. The size of microgap in the internal connection was significantly smaller compared to the external one.…”

“…Methylene blue leakage was higher in the external connection. (9) GapSeal is a silicone and bacteriostatic gel for implant cavity seal, which reduced microgap and microleakage in internal hex implant-abutment connections in the present study. The results of the previous studies that follow are in line with the present study.…”

“…Substances used for sealing the gap include silicone washer, chlorhexidine thymol varnish, and Gap-Seal. (8)(9)(10) Various studies have shown fluid flow and bacterial accumulation around the implant-abutment junction regardless of the type of connection (external or internal); gaps of up to 49 µm have been reported. (11)(12)(13)(14)(15)(16)(17) Studies have shown a lower rate of microgap and leakage with internal implant-abutment connection compared to the external ones.…”

“…(11)(12)(13)(14)(15)(16)(17) Studies have shown a lower rate of microgap and leakage with internal implant-abutment connection compared to the external ones. (9) The effect of sealants on microgap and microleakage reduction between fixtures and abutments in internal connections under dynamic loading has been limitedly studied. In 2014, Nayak et al reported the lowest bacterial growth rate in the GapSeal group compared to O-ring.…”