6 research outputs found
Preclinical Testing of Boron-Doped Diamond Electrodes for Root Canal Disinfection—A Series of Preliminary Studies
While numerous approaches have meanwhile been described, sufficient disinfection of root
canals is still challenging, mostly due to limited access and the porous structure of dentin. Instead of
using different rinsing solutions and activated irrigation, the electrolysis of saline using boron-doped
diamond (BDD) electrodes thereby producing reactive oxygen species may be an alternative approach.
In a first step, experiments using extracted human teeth incubated with multispecies bacterial biofilm
were conducted. The charge quantities required for electrochemical disinfection of root canals were
determined, which were subsequently applied in an animal trial using an intraoral canine model. It
could be shown that also under realistic clinical conditions, predictable disinfection of root canals
could be achieved using BDD electrodes. The parameters required are in the range of 5.5 to 7.0 V and
9 to 38 mA, applied for 2.5 to 6.0 min with approximately 5 to 8 mL of saline. The direct generation
of disinfective agents inside the root canal seems to be advantageous especially in situations with
compromised access and limited canal sizes. The biologic effect with respect to the host reaction on
BDD-mediated disinfection is yet to be examined
Pilot Study on the Use of a Laser-Structured Double Diamond Electrode (DDE) for Biofilm Removal from Dental Implant Surfaces
No proper treatment option for peri-implantitis exists yet. Based on previous studies
showing the in vitro effectiveness of electrochemical disinfection using boron-doped diamond
electrodes, novel double diamond electrodes (DDE) were tested here. Using a ceramic carrier and
a laser structuring process, a clinically applicable electrode array was manufactured. Roughened
metal discs (n = 24) made from Ti-Zr alloy were exposed to the oral cavities of six volunteers for
24 h in order to generate biofilm. Then, biofilm removal was carried out either using plastic curettes
and chlorhexidine digluconate or electrochemical disinfection. In addition, dental implants were
contaminated with ex vivo multispecies biofilm and disinfected using DDE treatment. Bacterial growth
and the formation of biofilm polymer were determined as outcome measures. Chemo-mechanical
treatment could not eliminate bacteria from roughened surfaces, while in most cases, a massive
reduction of bacteria and biofilm polymer was observed following DDE treatment. Electrochemical
disinfection was charge- and time-dependent and could also not reach complete disinfection in
all instances. Implant threads had no negative effect on DDE treatment. Bacteria exhibit varying
resistance to electrochemical disinfection with Bacillus subtilis, Neisseria sp., Rothia mucilaginosa,
Staphylococcus haemolyticus, and Streptococcus mitis surviving 5 min of DDE application at 6 V.
Electrochemical disinfection is promising but requires further optimization with respect to charge
quantity and application time in order to achieve disinfection without harming host tissue
Root Canal Obturation by Electrochemical Precipitation of Calcium Phosphates
Achieving adequate disinfection and preventing reinfection is the major goal in endodontic
treatment. Variation in canal morphology and open porosity of dentine prevents achieving complete
disinfection. Questionable biocompatibility of materials as well as a lack of sealing ability questions
the usefulness of current obturation methods. With a novel disinfection approach based on the
use of boron-doped diamond (BDD) electrodes having shown promising results it was the goal
of this series of experiments to investigate the possibility of BDD-mediated in situ forming of a
biocompatible obturation material. A combination of calcium phosphate and maleic acid was used
as precursor solution while Ion Chromatography Mass Spectrometry (IC-MS), Raman spectroscopy
(RAMAN), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), scanning electron
microscopy (SEM), dye penetration and micro-computed tomography (µCT) were applied for characterizing the precipitate. It was possible to achieve a BDD-mediated precipitation of brushite in a
clinically applicable timeframe. However, tight sealing of the canal system based on brushite could
not be achieved
Diamond as Insulation for Conductive Diamond—A Spotted Pattern Design for Miniaturized Disinfection Devices
Boron-doped diamond (BDD) electrodes are well known for the in situ production of strong oxidants. These antimicrobial agents are produced directly from water without the need of storage or stabilization. An in situ production of reactive oxygen species (ROS) used as antimicrobial agents has also been used in recently developed medical applications. Although BDD electrodes also produce ROS during water electrolysis, only a few medical applications have appeared in the literature to date. This is probably due to the difficulties in the miniaturization of BDD electrodes, while maintaining a stable and efficient electrolytic process in order to obtain a clinical applicability. In this attempt, a cannula-based electrode design was achieved by insulating the anodic diamond layer from a cathodic cannula, using a second layer of non-conducting diamond. The undoped diamond (UDD) layer was successfully grown in a spotted pattern, resulting in a perfectly insulated yet still functional BDD layer, which can operate as a miniaturized flow reactor for medical applications. The spotted pattern was achieved by introducing a partial copper layer on top of the BDD layer, which was subsequently removed after growing the undoped diamond layer via etching. The initial analytical observations showed promising results for further chemical and microbial investigations
Diamond as Insulation for Conductive Diamond : A Spotted Pattern Design for Miniaturized Disinfection Devices
Boron-doped diamond (BDD) electrodes are well known for the in situ production of strong
oxidants. These antimicrobial agents are produced directly from water without the need of storage or
stabilization. An in situ production of reactive oxygen species (ROS) used as antimicrobial agents has
also been used in recently developed medical applications. Although BDD electrodes also produce
ROS during water electrolysis, only a few medical applications have appeared in the literature to date.
This is probably due to the difficulties in the miniaturization of BDD electrodes, while maintaining a
stable and efficient electrolytic process in order to obtain a clinical applicability. In this attempt, a
cannula-based electrode design was achieved by insulating the anodic diamond layer from a cathodic
cannula, using a second layer of non-conducting diamond. The undoped diamond (UDD) layer was
successfully grown in a spotted pattern, resulting in a perfectly insulated yet still functional BDD
layer, which can operate as a miniaturized flow reactor for medical applications. The spotted pattern
was achieved by introducing a partial copper layer on top of the BDD layer, which was subsequently
removed after growing the undoped diamond layer via etching. The initial analytical observations
showed promising results for further chemical and microbial investigations
Root Canal Obturation by Electrochemical Precipitation of Calcium Phosphates
Achieving adequate disinfection and preventing reinfection is the major goal in endodontic treatment. Variation in canal morphology and open porosity of dentine prevents achieving complete disinfection. Questionable biocompatibility of materials as well as a lack of sealing ability questions the usefulness of current obturation methods. With a novel disinfection approach based on the use of boron-doped diamond (BDD) electrodes having shown promising results it was the goal of this series of experiments to investigate the possibility of BDD-mediated in situ forming of a biocompatible obturation material. A combination of calcium phosphate and maleic acid was used as precursor solution while Ion Chromatography Mass Spectrometry (IC-MS), Raman spectroscopy (RAMAN), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), dye penetration and micro-computed tomography (µCT) were applied for characterizing the precipitate. It was possible to achieve a BDD-mediated precipitation of brushite in a clinically applicable timeframe. However, tight sealing of the canal system based on brushite could not be achieved