To develop a risk of bias tool for pre-clinical dental materials research studies that aims to support reporting of future investigations and improve assessment in systematic reviews. A four-stage process following EQUATOR network recommendations was followed, which included project launch, literature review, Delphi process and the tool finalization. With the support of the European Federation of Conservative Dentistry (EFCD) and the Dental Materials Group of the International Association for Dental Research (DMG-IADR), a total of 26 expert stakeholders were included in the development and Delphi vote of the initial proposal. The proposal was built using data gathered from the literature review stage. During this stage, recent systematic reviews featuring dental materials research, and risk of bias tools found in the literature were comprehensively scanned for bias sources. The experts thus reached a consensus for the items, domains and judgement related to the tool, allowing a detailed guide for each item and corresponding signalling questions. The tool features nine items in total, spread between 4 domains, pertaining to the following types of bias: bias related to planning and allocation (D1), specimen preparation (D2), outcome assessment (D3) and data treatment and outcome reporting (D4). RoBDEMAT, as presented, features signalling questions and a guide that can be used for RoB judgement. Its use as a checklist is preferred over a final summary score. RoBDEMAT is the first risk of bias tool for pre-clinical dental materials research, supported and developed by a broad group of expert stakeholders in the field, validating its future use. This new tool will contribute the study field by improving the scientific quality and rigour of dental materials research studies and their systematic reviews. Such studies are the foundation and support of future clinical research and evidence-based decisions.

Statement of the Problem:  Many regions in the world do not have electricity, water, or access to dental facilities that allows the treatment of caries with dental handpieces and rotary burs. For restorative techniques used in these regions, an antibacterial self‐adherent glass ionomer material would contribute considerably.Purpose:  This study aimed to test if chlorhexidine diacetate (Fluka BioChemika, Buchs, Switzerland)‐ or chlorhexidine digluconate (Sigma‐Aldrich, Steinheim, Germany)‐added ChemFil Superior glass ionomer cement (Dentsply DeTrey, Konstanz, Germany) had any long‐term antibacterial effect against certain oral bacteria and to test the new formulation’s physical properties.Materials and Methods:  ChemFil Superior was used as a control. Chlorhexidine diacetate (powder) was added to the powder and chlorhexidine digluconate (liquid) was mixed with the powder in order to obtain 0.5, 1.25, and 2.5% concentrations of the respective groups. Setting time, compressive strength, and acid erosion were tested according to ISO 9917‐1. Working time, hardness, diametral tensile strength, and biaxial flexural strength were also determined. Long‐term antimicrobial activity against S. mutans, L. acidophilus, and C. albicans were tested with the agar diffusion method. Analysis of variance (ANOVA) was used for comparison (p < 0.05).Results:  Regarding the immediate antibacterial effect for S. mutans, all the tested groups showed inhibitions of the strain compared with the control group (p < 0.05), with larger zones for the higher concentration groups and all the diacetates. For L. acidophilus, all the groups were effective compared with the control, but the greatest antibacterial effect was observed with the 2.5% diacetate group. The 2.5% group of chlorhexidine diacetate showed antibacterial activity up to 90 days against S. mutans and up to 60 days against L. acidophilus. The working and setting time, acid erosion test, diametral tensile strength, and biaxial flexural strength of the tested groups were not different from the control ChemFil group. However, the 1.25 and 2.5% groups of chlorhexidine diacetate had significantly lower compressive strengths than the control group. Lower hardness values were obtained with the 0.5 and 2.5% chlorhexidine digluconate groups in comparison with the control group.CLINICAL SIGNIFICANCE: The results of this in vitro investigation demonstrated that chlorhexidine diacetate or digluconate added to the ChemFil Superior glass ionomer material can exhibit long‐term antibacterial effects against S. mutans and L. acidophilus without compromising the physical properties of the material.(J Esthet Restor Dent 20:29–45, 2008)