Three-dimensional topographic and metrologic evaluation of dental implants by confocal laser scanning microscopy

Surface topography of dental implants has changed during the past few years; however, the last systematic study on this topic is dated 1993.

The aim of this study was to correlate dental implants by surface analysis.

A microtopographic analysis of 35 dental implants was performed using confocal laser scanning microscopy. Roughness value (Sa) and developed surface area (ratio, Sdr) were calculated. Implants were grouped according to their surface treatment: "minimally rough" with no further surface treatment (n = 2); ablative structured using etching or blasting (n = 17); titanium plasma spray coated (TPS; n = 9); coated with hydroxyapatite (HA; n = 7).

Most implants (n =16) showed Sa values between 3.0 and 5.0 microm. The developed surface area has a mean value of 13.5 and an SD of 6.52. Minimally rough implant surfaces show the lowest Sa values (mean 0.5 microm). Implants with ablative surface treatment have mean Sa values of 3.1 microm. Both groups with additive surface treatment (TPS and HA) present similar roughness values with a mean of 6.0 microm and 5.8 microm, respectively. Ratio Sdr ranges from 3.1 for the minimally rough implants to 11.4 for the ablative treated implants and 14.3 for TPS-coated and 18.4 for HA-coated implants. There is a significant difference between the roughness and ratio values of the different groups. The topographic images show a typical surface according to the underlying surface treatment.

We can confirm the "classic" grouping of dental implants by type of surface treatment into the groups minimally rough, ablative, TPS coated, and HA coated as these treatments lead to different ascending Sas; however, the additional value of the ratio Sdr including both spatial and amplitude aspects of the surface could not be confirmed in this study. Functional parameters describing the topographic differences are still lacking.