Abstract of the study:

Background: 

Although 5-year clinical data exist for different zirconia implants, no analysis has yet been performed focusing on how the surface topography of the implant affects clinical parameters.

Purpose: 

To analyze the influence of zirconia implant topography on first bone implant contact (fBIC).

Materials and methods:

 In a prospective two-center cohort investigation 63 zirconia implants were evaluated at implant placement, prosthetic delivery, 1, 3, and 5 years. The distance (DIB) between implant shoulder and fBIC was measured at each time point in periapical radiographs at mesial and distal sites. Two-way ANOVA/Bonferroni was used to analyze the effects of time and center (α < 0.05).

Results: 

Between the centers, the mean DIB varied significantly at implant placement (Freiburg [FR]: 1.4 ± 0.6 mm; Zurich [ZH]: 0.8 ± 0.5 mm). Thereafter, no statistically significant difference in DIB was observed, neither between centers nor between time points (prosthetic delivery: FR: 1.9 ± 0.6 mm, ZH: 1.7 ± 0.8 mm; 1 year: FR: 1.8 ± 0.6 mm, ZH: 1.6 ± 0.8 mm; 3 years: FR: 1.9 ± 0.8 mm, ZH: 1.7 ± 0.8 mm; 5 years: FR: 1.9 ± 0.8 mm, ZH 1.8 ± 0.6 mm). The overall mean DIB at prosthetic delivery to 5 years of both centers (1.8 ± 0.7 mm) is located within the transition zone between the smooth neck and the moderately rough intraosseous part (1.6-2.0 mm from the implant shoulder). However, individual DIB values are ranging from 0.1 to 4.2 mm overlapping the transition zone.

Conclusions: 

The standard deviation of the DIB indicates that the fBIC establishes on moderately rough and smooth surfaces. Consequently, soft tissue adapts to both topographies as well.

Keywords: 

bone-implant interface; clinical study; implant design; implant surface; surface topography; zirconia.

EACim commentary on the article:

More than half a century after dental implantology became an integral part of our daily practice, the technological contributions are significant.

Two concepts have proved to be decisive: ceramic implantology with the fantastic contribution of zirconia and the changes in surface conditions from a macroscopically smooth surface (machined implant) to so-called rough surfaces. Most of the current implants have a moderately rough surface.

A major disadvantage of these rough surfaces is the reaction they can cause to the surrounding tissue. The increased accumulation of dental plaque, together with a pro-inflammatory peri-implant stimulation, can result in peripheral osteolysis and a mucosal inflammatory state, which quite frequently leads to peri-implantitis.

It was thus interesting to elucidate, in a multicentre study, the behaviour of peripheral tissues towards different “smooth” or “rough” zirconia surfaces

The excellent reaction around zirconia implants is well known, both in terms of bone and mucosa. The good surprise is that the peri-implant tissues seem to behave in the same way in contact with the different ceramic implant surfaces.

Histological data from animal studies would certainly have been appreciated.