Evaluation of biofilm formation on acrylic resins used to fabricate dental temporary restorations with the use of 3D printing technology

Abstract

Background Temporary implant-retained restorations are required to support function and esthetics of the masticatory system until the final restoration is completed and delivered. Acrylic resins are commonly used in prosthetic dentistry and lately they have been used in three-dimensional (3D) printing technology. Since this technology it is fairly new, the number of studies on their susceptibility to microbial adhesion is low. Restorations placed even for a short period of time may become the reservoir for microorganisms that may affect the peri-implant tissues and trigger inflammation endangering further procedures. The aim of the study was to test the biofilm formation on acrylamide resins used to fabricate temporary restorations in 3D printing technology and to assess if the post-processing impacts microbial adhesion. Methods Disk-shaped samples were manufactured using the 3D printing technique from three commercially available UV-curable resins consisting of acrylate and methacrylate oligomers with various time and inhibitors of polymerization (NextDent MFH bleach, NextDent 3D Plus, MazicD Temp). The tested samples were raw, polished and glazed. The ability to create biofilm by oral streptococci (S. mutans, S. sanguinis, S. oralis, S. mitis) was tested, as well as species with higher pathogenic potential: Staphylococcus aureus, Staphylococcus epidermidis and Candida albicans. The roughness of the materials was measured by an atomic force microscope. Biofilm formation was assessed after 72 h of incubation by crystal violet staining with absorbance measurement, quantification of viable microorganisms, and imaging with a scanning electron microscope (SEM). Results Each tested species formed the biofilm on the samples of all three resins. Post-production processing resulted in reduced roughness parameters and biofilm abundance. Polishing and glazing reduced roughness parameters significantly in the NextDent resin group, while glazing alone caused significant surface smoothing in Mazic Temp. A thin layer of microbial biofilm covered glazed resin surfaces with a small number of microorganisms for all tested strains except S. oralis and S. epidermidis, while raw and polished surfaces were covered with a dense biofilm, rich in microorganisms. Conclusions UV-curing acrylic resins used for fabricating temporary restorations in the 3D technology are the interim solution, but are susceptible to adhesion and biofilm formation by oral streptococci, staphylococci and Candida. Post-processing and particularly glazing process significantly reduce bacterial biofilm formation and the risk of failure of final restoration.

Microbiological evaluation of conjunctival anopthalmic flora after using digital 3D-printed ocular prosthesis compared to conventional one: a randomized clinical trial

“…Their results showed that CAD/CAM PMMA-based polymers had less surface roughness and less adhesion of Candida albicans. Mazurek et al [ 44 ] evaluated biofilm formation on 3D-printed temporary restorations and assessed the post-processing impact on microbial adhesion. They found that roughness itself was not the main factor affecting microbial adhesion to 3D-printed resin.…”

Biocompatibility and biofilm formation on conventional and CAD/CAM provisional implant restorations

“…The complex chemical compositions of novel dental provisional implant restorations fabricated by different techniques have been the subject of various studies [ 10 , 16 , 17 , 20 ]. It has been reported that incomplete polymerization of the material and the presence of toxic monomers can negatively affect the biologic response, particularly after surgical procedures such as implant placement where the provisional restoration is in close contact with the surgical site [ 8 , 21 ].…”

“…Although numerous studies have investigated the mechanical properties of provisional CAD/CAM restorations [ 11 – 15 ], few studies have focused on the biological response of these materials, especially in the context of provisional implant restorations [ 16 , 17 ]. Provisional restorations are close contact with gingival tissue, hence ensuring their biocompatibility and promoting tissue integration are of paramount importance to prevent any adverse reactions in the adjacent tissues.…”

Main approaches of biofilm formation in composite resins: a concise systematic review

“…In addition, the literature reports that deficiencies resulting from the polymerization contraction of composite resins persist [7,18]. Shrinkage is a physical process inherent to the healing reaction and causes tension at the toothrestoration interface that can lead to marginal microleakage of oral fluids and microorganisms.…”