Adhäsionsverhalten von Multispezies-Biofilmen aus Aggregatibacter actinomycetemcomitans, Staphylococcus epidermidis und Streptococcus sanguinis auf Titanoberflächen in vitro

by Jana Marisa Westa née Friebel
Doctoral thesis
Date of Examination:2025-03-07
Date of issue:2025-02-25
Advisor:Prof. Dr. Ralf Bürgers
Referee:Prof. Dr. Ralf Bürgers
Referee:Prof. Dr. Annette Wiegand
Persistent Address: http://dx.doi.org/10.53846/goediss-11097

 

 

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Abstract

English

Objective: Biofilm-associated peri-implant diseases are a major cause of the loss of osseointegrated dental implants. The accumulation of oral biofilms is primarily influenced by the surface topography of biomaterials particularly their roughness. The microbial spectrum of peri-implantitis is variable, with certain bacterial species being strongly associated with peri-implant inflammations. While the adhesion of mono-species biofilms in relation to surface characteristics is widely described in the literature, studies involving multi-species biofilms are rare. The changes in the species composition of multi-species biofilms depending on the roughness of titanium surfaces have not yet been investigated. The present study aims to investigate the adhesion behavior of multi-species biofilms composed of the non-pathogenic early colonizer Streptococcus sanguinis and the peri-implant disease-associated bacteria Aggregatibacter actinomycetemcomitans and Staphylococcus epidermidis. Materials/Method: Four titanium surfaces were compared: two clinically used titanium implant surfaces (Hager & Meisinger GmbH, Neuss, Germany and Semados titanium implants, BEGO GmbH & Co KG, Bremen, Germany) and two laboratory-prepared titanium surfaces (super-polished and sandblasted). The titanium surfaces were characterized using confocal and scanning electron microscopy. A. actinomycetemcomitans and S. epidermidis were cultured together with S. sanguinis in a multi-species biofilm on the four titanium materials. The cultivated mono- and multi-species biofilms were analyzed using fluorescence and scanning electron microscopy. Biofilm formation was determined based on the amount of total DNA extracted from the bacteria. The relative composition of the multi-species biofilms was analyzed using real-time PCR. Results: The average roughness (Ra) value for implant surface I (Hager & Meisinger) was 1.325 µm and for implant surface II (BEGO) was 1.405 µm. The Ra values for the super-polished (0.062 µm) and sandblasted (0.505 µm) surfaces were lower. The free surface energy (average values: super-polished: 55.430 mN/m, sandblasted: 63.934 mN/m, implant surface I: 65.214 mN/m, implant surface II: 59.006 mN/m) was measured using contact angle measurement. Fluorescence and scanning electron microscopy images showed successful microbial colonization by single- and multi-species cultures on all test surfaces. Statistical analysis of DNA concentrations and Ct values revealed no significant differences between the test materials. Conclusion: The present in vitro study found no significant impact of the surface topography of the investigated implant surfaces on the quantity of biofilm accumulation and the composition of bacterial multi-species biofilms. The clinical applicability of these findings must be verified through future in vivo studies.
Keywords: Peri-implantitis; Dental implants; Oral biofilm; real-time PCR; Titanium implants