Marginal adaptation and microbial leakage at conometric prosthetic connections for implant-supported single crowns: an in vitro investigation

  • Encouraging clinical results were reported on a novel cone-in-cone coupling for the fixation of dental implant-supported crowns (Acuris, Dentsply Sirona Implants, Mölndal, Sweden). However, the presence or absence of a microgap and a potential bacterial leakage at the conometric joint has not yet been investigated. A misfit and a resulting gap between the conometric components could potentially serve as a bacterial reservoir that promotes plaque formation, which in turn may lead to inflammation of the peri-implant tissues. Thus, a two-fold study set-up was designed in order to evaluate the bidirectional translocation of bacteria along conometrically seated single crowns. On conometric abutments filled with a culture suspension of anaerobic bacteria, the corresponding titanium nitride-coated (TiN) caps were fixed by friction. Each system was sterilized and immersed in culture medium to provide an optimal environment for microbial growth. Positive and negative controls were prepared. Specimens were stored in an anaerobic workstation, and total and viable bacterial counts were determined. Every 48 h, samples were taken from the reaction tubes to inoculate blood agar plates and to isolate bacterial DNA for quantification using qrt-PCR. In addition, one Acuris test system was subjected to scanning electron microscopy (SEM) to evaluate the precision of fit of the conometric coupling and marginal crown opening. Throughout the observational period of one week, blood agar plates of the specimens showed no viable bacterial growth. qrt-PCR, likewise, yielded a result approaching zero with an amount of about 0.53 × 10−4 µg/mL DNA. While the luting gap/marginal opening between the TiN-cap and the ceramic crown was within the clinically acceptable range, the SEM analysis failed to identify a measurable microgap at the cone-in-cone junction. Within the limits of the in-vitro study it can be concluded that the Acuris conometric interface does not allow for bacterial translocation under non-dynamic loading conditions.

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Author:Peter GehrkeORCiDGND, Philip HartjenORCiDGND, Ralf SmeetsORCiDGND, Martin GosauGND, Ulrike PetersORCiD, Thomas BeiklerORCiDGND, Carsten FischerORCiD, Carolin StolzerGND, Jürgen Geis-GerstorferORCiDGND, Paul WeiglORCiD, Sogand SchäferORCiD
Parent Title (English):International journal of molecular sciences
Publisher:Molecular Diversity Preservation International
Place of publication:Basel
Document Type:Article
Date of Publication (online):2021/01/17
Date of first Publication:2021/01/17
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2023/11/28
Tag:Acuris; CAD/ CAM crown; bacterial leakage; conical coupling; conometric connection; marginal fit
Issue:2, art. 881
Article Number:881
Page Number:12
First Page:1
Last Page:12
Correspondence to Schäfer, Sogand: sog.schä
Dewey Decimal Classification:6 Technik, Medizin, angewandte Wissenschaften / 61 Medizin und Gesundheit / 610 Medizin und Gesundheit
Licence (German):License LogoCreative Commons - CC BY - Namensnennung 4.0 International