Introduction:
Implant abutments play an important role in the success of prosthetic treatment based on dental implants. Failure prevention may also depend on the alignment of the connecting elements. The correlation between the gap of an implant platform and the connector, bacterial colonization and the subsequent formation of periimplantitis was observed.

Aim of the study:
The aim of the study was a laboratory assessment of the tightness of antirotation elements in the implant - hybrid abutment and implant – all ceramic abutment system.

Material and methods:
The material for the research on the marginal fit of the anti-rotation elements were divided on two groups of abutments: individual hybrid, metal-ceramic and individual all-ceramic abutments. Metal-ceramic hybrid abutments were made of a titanium metal base by Swiss-Medent (Switzerland), the ceramic part of this abutment was milled from Robocam ceramics (Poland) All-ceramic abutments were made of the same ceramic type. To assess the marginal seal, a scanning microscope (SEM) examination was used. The examination included the analysis of the connection surface of the platform of Nobel Biocare Replace (Sweden) implant with the hybrid and ceramic abutments. The analysis was carried out by measuring three points concerning the dimension of the connection gap.

Results:
Average connection gap in hybrid abutments was 15,637 µm (min = 10,12 µm, max 21,68 µm, delta 11,56 µm). For an all-ceramic abutments the mean width of the connection gap was 19.242 µm (min = 10.39 µm, max = 34.41 µm delta = 24.02 µm).

Conclusions:
Statistically significant differences in the width of the gap between the implant platform and a connector was occurred. The hybrid abutments showed a significantly better fit compared to the all-ceramic ones.