Osseointegrated implants placed at supracrestal level may harbour higher counts of A. gerencseriae and S. constellatus – a randomized, controlled pilot study

Abstract

PurposeThis study aimed at evaluating the bacterial colonization in dental implants inserted in the crestal or supracrestal position and correlated it to radiographic bone measurements.MethodsThirty-five implants with regular platform in nine patients (mean age 62.4±11.2 years) were inserted either at the bone crest level (control group) or at a suprecrestal level (test group). Radiographic examination was performed at baseline (implant installation) and after 6 months. Clinical and microbiological data were collected after 6 months. Digital radiography was used to assess bone remodeling (marginal bone loss and optical alveolar density). Bacterial profile was analyzed by checkerboard DNA–DNA hybridization, including a panel of 40 bacterial species.ResultsAfter 6 months, there were significantly higher counts of Actinomyces gerencseriae (p=0.009) and Streptococcus constellatus (p=0.05) in the test group. No significant differences between test and control groups were observed for marginal bone loss (p=0.725) and optical alveolar density (p=0.975). Probing depth was similar in both groups.ConclusionSignificantly higher counts of A. gerencseriae and S. constellatus were found in implants placed at the supracrestal level compared to the ones placed at the bone level. No relation was found between the installation level of dental implants and peri-implant bone remodeling.

Microbial evaluation of implant surface

“…However, some interesting studies have been previously carried out assessing microbial contamination, mainly comparing different abutment designs. In a study conducted by de Moraes Rego et al 16 significantly higher counts of A. gerencseriae and S. constellatus were found in implants placed at the supracrestal level compared to the ones placed at the bone level. No relation was found between the installation level of dental implants and peri-implant bone remodeling.…”

“…This may be explained by the existence of a microgap between the abutment and the implant, which is an area where there is a higher concentration of microorganisms. Thus, the greater the gap between the implant and the abutment, the greater the microbial contamination in the area, leading to greater bone loss [8][9][16][17][18] .…”