Elsevier

Dental Materials

Volume 36, Issue 3, March 2020, Pages e59-e73
Dental Materials

Standardization of antimicrobial testing of dental devices

https://doi.org/10.1016/j.dental.2019.12.006Get rights and content

Abstract

Objective

Dental device is a very broad term that can be used to include any foreign material or product that is introduced in the host oral cavity to replace missing tissues. These devices are subjected to different environments which include dental hard tissues, tissue fluids, blood and saliva. All dental devices are continuously challenged microbiologically and a number of failures in clinical management are related to microbial colonization. Thus, the assessment of the antimicrobial properties of dental devices are extremely important. In this paper, a classification of dental devices is being proposed. This classification distinguishes the devices based on whether they are implantable or not, and also sub-classified based on their specific application and the substrate receiving the device.

Methods and Results

A literature search was conducted to identify how dental devices have been tested with relation to the microbial strains used and whether the testing has been performed in isolation or reported with other relevant tests such as material characterization and biological activity.

The results of the literature review were analyzed and recommendations for antimicrobial testing of dental devices are proposed. These recommendations include the need for the setting up of pre-testing parameters such as ageing and the details of the pre-testing sterilization procedures, as these may affect the material chemistry and the specification for antimicrobial testing to be done with specific single strains or polymicrobial that are native to the region where the device is located are also suggested. Testing can be undertaken in vitro, ex vivo and in vivo. Since the antimicrobial and biological activities influence/condition one another and the material chemistry may affect both the antimicrobial and biological testing this document also makes recommendations regarding biological assessment which can be carried out in isolation or integrated with the microbiological testing and also material testing methods including chemical and physical characterization of bulk, surface, eluted and degraded materials as well as physical characterization methods.

Significance

The level of standardization of antimicrobial testing for the dental devices needs to be based on the device location and host interaction in order to increase the clinical applicability of the mentioned tests.

Introduction

There is no proposed definition of a dental device. Dental devices are part of the medical devices which are defined as any instrument, apparatus, appliance, software, material, or other article used in medical practice. This includes devices used alone or in combination with software necessary for diagnosis, prevention, monitoring, treatment or alleviation of disease [1]. A dental device can thus also be similarly defined and includes the specific use in the oral cavity. A dental device is any foreign material or product that is introduced in the host oral cavity to replace missing tissues. It is a very broad term that encompasses several devices used in the oral cavity, which serve different purposes, interact with different tissues and are in contact with different oral environments. The oral cavity has various commensal microorganisms that are not pathogenic to the host. Thus, the desired level of antimicrobial activity of dental devices varies with the location, clinical use of the device and the environment in which it is placed and the time of implantation.

Various methods for testing antimicrobial activity of dental devices are described in different papers testing both established materials already in clinical use and prototypes that still need to be further evaluated. Due to the wide range of dental devices, it is necessary to classify and consider the clinical needs prior to assessing the antimicrobial activity. Furthermore, the level of testing should reflect the degree of risk posed on the host. Dental devices can also be classified differently if they have anti-microbiological effects either as a prevention device of future infections or as a treatment device used on already installed infection. Testing should enclose different microbiological characteristics of these different environments. A basic classification is proposed for dental devices as shown in Fig. 1. This classification distinguishes the devices on whether they are implantable or not, and sub-classified depending on their specific application and the substrate receiving the device.

In dentistry, failure in clinical management is mostly related to bacterial infection. Thus, all dental devices should be tested for antimicrobial properties. Unlike the testing of biological properties, there are no specific standards for the testing of antimicrobial properties.

The specific objectives of this paper are to (i) review the literature to identify how dental devices have been tested with relation to the microbial strains used and whether the testing has been performed in isolation or reported with other relevant tests such as material characterization and biological activity; (ii) suggest a level of standardization of antimicrobial testing for the dental devices based on the device location and host interaction.

Section snippets

Part 1: literature review

Based on the classification proposed in Fig. 1, where dental devices were classified as implantable and non-implantable and sub-classified on the field of specialization and the contact with specific environments, searches were conducted using PubMed search engine for devices subdivided into 7 groups namely:

  • -

    Implantable for oral surgery

  • -

    Implantable for implantology

  • -

    Implantable for periradicular surgery

  • -

    Non-implantable for restorative dentistry-prosthodontics

  • -

    Non-implantable for restorative

Results

After the inclusion and exclusion criteria were applied the articles to be included for each subgroup are shown in Table 2.

Conclusions

This document outlines the recommendations for characterization and standardization of antimicrobial testing of dental devices. The methods suggested are established methods that have been thoroughly tried and tested and are thus reliable. The full testing methodology is shown in Fig. 2.

Acknowledgements

COST action TD 1305: IPROMEDAI- Improved Protection of Medical Devices Against Infection.

The following are also acknowledged for their contribution in the discussions:

Reto Luginbuehl, University of Bern, Bern, Switzerland; Moter Annette, Charité-Universitätsmedizin Berlin, Germany; Thevissen Karin, KU, Leuven, Belgium; Furtos Gabriel, Raluca Ripan Institute of Research in Chemistry, Babes-Bolyai, University, Romania; Gameiro Paula, Faculdade de Ciências da Universidade do Porto, Portugal;

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