Guidelines for Reporting Pre-clinical In Vitro Studies on Dental Materials

In vitro pre-clinical research is an important aspect of the development of new dental materials and techniques, because it can provide essential information for further testing of therapeutic approaches in clinical trials. These pre-clinical experiments should therefore be reported with the same rigor as studies involving humans. The objectives of this paper were twofold: (a) to search and assess existing guidelines for reporting in vitro studies in dentistry, and (b) to present a methodology for reporting these studies, based on the CONSORT checklist for reporting randomized clinical trials. After a comprehensive search in PubMed database, no guidelines for reporting in vitro studies in dentistry were found. The proposed methodology is presented and the rationale for the choice of fourteen guidelines for producing the different sections of such papers is described in detail. The assessment of a sample of in vitro studies using the proposed guidelines showed that the standards of reporting should be improved. Good standards of reporting of studies are necessary for improvement of efficiency in dental research. The guidelines presented are the first standards for reporting in vitro studies in dentistry. As with the original CONSORT document, the modified checklist is evolving. It should, therefore, be further tested by researchers and the results of these assessments should be used for further improvement of this tool.

Introduction

In vitro research for assessing potential new materials or techniques to be further tested in vivo, i.e., on animals and humans, is an important aspect of dentistry. One advantage of in vitro research is that it enables researchers to perform single-variable experiments under controlled conditions.¹ Although in vitro research cannot reproduce a dynamic environment, for example the stomatognathic system, pre-clinical experiments can provide important information about the properties and characteristics of a new material or technique. This information is of fundamental importance when testing efficacy in more robust studies, for example randomized clinical trials. It is, therefore, necessary to conduct in vitro research of the highest possible standard. Biased information from pre-clinical experiments is likely to lead to biased clinical studies.

In restorative dentistry many studies test the biocompatibility and/or toxicity² and efficacy of dental materials, for example composites, using extracted animal or human teeth.3, 4, 5, 6 Because systematic reviews of dental in vitro studies are becoming frequent,7, 8, 9, 10 maximization of the output from such research is essential. Moreover, good standards in reporting are required to provide interested people—readers, researchers, and editors—with detailed information indicating whether the research was appropriate and which aspects might need more scrutiny.¹¹ Some efforts were made in the last years to improve the quality of reporting of scientific literature. For example, the Consolidated Standards of Reporting Trials (CONSORT) checklist was developed to assist authors in writing reports of randomized controlled trials.¹² Although the CONSORT checklist was not originally designed for designing, conducting, and analyzing trials, its use may indirectly affect their design and conduct.¹²

The objectives of the present work were twofold: (a) to critically assess the literature on guidelines on the report of in vitro research in dentistry. The focus was on guidelines for reporting in vitro studies, instead of performing some specific experiment; and (b) to describe a checklist developed for reporting pre-clinical (in vitro) studies of dental materials, using modified items described in the CONSORT checklist. A sample of in vitro studies was tested with this new methodology and the results are presented. The idea is to improve conducting and reporting of pre-clinical testing of dental materials with potential for use in clinical treatment as to possibly minimize bias and optimize efficacy for subsequent RCTs.