Evaluation of biofilm colonization on multi-part dental implants in a rat model

Abstract

Background Peri-implant mucositis and peri-implantitis are highly prevalent biofilm-associated diseases affecting the tissues surrounding dental implants. As antibiotic treatment is ineffective to fully cure biofilm mediated infections, antimicrobial modifications of implants to reduce or prevent bacterial colonization are called for. Preclinical in vivo evaluation of the functionality of new or modified implant materials concerning bacterial colonization and peri-implant health is needed to allow progress in this research field. For this purpose reliable animal models are needed. Methods Custom made endosseous dental implants were installed in female Sprague Dawley rats following a newly established three-step implantation procedure. After healing of the bone and soft tissue, the animals were assigned to two groups. Group A received a continuous antibiotic treatment for 7 weeks, while group B was repeatedly orally inoculated with human-derived strains of Streptococcus oralis, Fusobacterium nucleatum and Porphyromonas gingivalis for six weeks, followed by 1 week without inoculation. At the end of the experiment, implantation sites were clinically assessed and biofilm colonization was quantified via confocal laser scanning microscopy. Biofilm samples were tested for presence of the administered bacteria via PCR analysis. Results The inner part of the custom made implant screw could be identified as a site of reliable biofilm formation in vivo. S. oralis and F. nucleatum were detectable only in the biofilm samples from group B animals. P. gingivalis was not detectable in samples from either group. Quantification of the biofilm volume on the implant material revealed no statistically significant differences between the treatment groups. Clinical inspection of implants in group B animals showed signs of mild to moderate peri-implant mucositis (4 out of 6) whereas the mucosa of group A animals appeared healthy (8/8). The difference in the mucosa health status between the treatment groups was statistically significant (p = 0.015). Conclusions We developed a new rodent model for the preclinical evaluation of dental implant materials with a special focus on the early biofilm colonization including human-derived oral bacteria. Reliable biofilm quantification on the implant surface and the symptoms of peri-implant mucositis of the bacterially inoculated animals will serve as a readout for experimental evaluation of biofilm-reducing modifications of implant materials.

The use of the phrase “data not shown” in dental research

“…"As elaborated in a preliminary experiment (data not shown), the amount of biofilm on the outer surface of the experimental abutments in both treatment groups was very variable." [16] Negative results Results that did not show statistically significant effect/association on some threshold, e.g., p > 0.05.…”

Swarming Magnetic Photoactive Microrobots for Dental Implant Biofilm Eradication

“…Bacterial biofilms develop many types of survival mechanisms to adapt to the surrounding conditions and environment. They are resistant to temperature and pH fluctuations, UV exposure, depletion of nutrients, and antimicrobial compounds such as antibiotics. ,, A healthy tooth is connected to the gum by a bacterially tight closure: the dentogingival junction . The dental implant is not able to form a bacterially tight connection with the gums.…”

“…1,2,5 A healthy tooth is connected to the gum by a bacterially tight closure: the dentogingival junction. 38 The dental implant is not able to form a bacterially tight connection with the gums. This represents the biggest technical disadvantage of a dental implant.…”

“…The oral cavity is colonized by a large number of aerobic and anaerobic bacteria. 6,38 This fact, together with the absence of a bacterially tight connection between the gum and the implant, leads to a constant penetration of bacteria from the mouth to the bone. However, bone is not naturally developed to be in contact with food and bacteria.…”

Biomimetic Implant Surfaces and Their Role in Biological Integration—A Concise Review

“…The chemical properties of biomaterial surfaces play an essential role in cell-biomaterial interaction and consequently in the osseointegration process. There is a growing concern about bacterial colonization and biofilm formation on dental implants, leading to the development of new implant materials and antibacterial implant surfaces [ 69 , 101 ]. The addition of bioactive components to implant surfaces can be classified into two groups: one that favors cell adhesion and the osseointegration process and the other that decreases bacterial adhesion and biofilm formation [ 24 , 83 , 102 , 103 ].…”