Antibacterial bonding agents could combat recurrent caries at the tooth-composite margins. The objectives of this study were to develop novel antibacterial dentin primers containing quaternary ammonium dimethacrylate (QADM) and nanoparticles of silver (NAg), and to investigate the effects on dentin bond strength and dental plaque microcosm biofilms for the first time. Scotchbond Multi-Purpose (“SBMP”) bonding agent was used. QADM and NAg were incorporated into SBMP primer, yielding 4 primers: SBMP primer (control), control + 10% QADM (mass), control + 0.05% NAg, and control + 10% QADM + 0.05% NAg. Human saliva was collected to grow microcosm biofilms. The NAg particle size (mean ± SD; n = 100) was 2.7 ± 0.6 nm. Dentin shear bond strengths (n = 10) with human third molars were approximately 30 MPa for all groups (p > 0.1). QADM-NAg-containing primer increased the bacteria inhibition zone by 9-fold, compared with control primer (p < 0.05). QADM-NAg-containing primer reduced lactic acid production and colony-forming units of total micro-organisms, total streptococci, and mutans streptococci by an order of magnitude. In conclusion, novel QADM-NAg-containing primers were strongly antibacterial without compromising dentin bond strength, and hence are promising to inhibit biofilms and secondary caries. The processing method of incorporating QADM and NAg together into the same primer produced the strongest antibacterial effect, which could have a wide applicability to other bonding systems.

Dental caries is the most widespread disease and an economic burden. Nanotechnology is promising to inhibit caries by controlling biofilm acids and enhancing remineralization. Nanoparticles of silver were incorporated into composites/adhesives, along with quaternary ammonium methacrylates (QAMs), to combat biofilms. Nanoparticles of amorphous calcium phosphate (NACP) released calcium/phosphate ions, remineralized tooth-lesions and neutralized acids. By combining nanoparticles of silver/QAM/NACP, a new class of composites and adhesives with antibacterial and remineralization double benefits was developed. Various other nanoparticles including metal and oxide nanoparticles such as ZnO and TiO2, as well as polyethylenimine nanoparticles and their antibacterial capabilities in dental resins were also reviewed. These nanoparticles are promising for incorporation into dental composites/cements/sealants/bases/liners/adhesives. Therefore, nanotechnology has potential to significantly improve restorative and preve...

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.