Comparison of the Intensity of Biofilm Production by Oral Microflora and Its Adhesion on the Surface of Zirconia Produced in Additive and Subtractive Technology: An In Vitro Study.

BACKGROUND: This in vitro study set out to find out how well oral cavity-dwelling bacteria can form biofilms and adhere on the surfaces of zirconium oxide samples created by 3D printing and milling technologies. METHODS: 5 strains of microorganisms were used for the study, and 40 zirconium oxide samples were prepared, which were divided into two groups (n = 20)-20 samples produced using removal technology comprised the control group, while 20 samples produced by 3D printing technology comprised the test group. The prepared samples were placed in culture media of bacteria and fungi that naturally occur in the oral cavity. Then, the intensity of biofilm build-up on the samples was determined using qualitative and quantitative methods. The results for both materials were compared with each other. RESULTS: No variations in the degree of biofilm deposition on zirconium oxide samples were found for the microorganisms Streptococcus mutans, Pseudomonas aeruginosa, Enterococcus faecalis, and Staphylococcus aureus. For Candida albicans fungi, more intense biofilm deposition was observed on samples made using 3D printing technology, but these differences were not statistically significant. CONCLUSION: The biofilm accumulation intensity of ceramics produced by additive technology is comparable to that of milled zirconium oxide, which supports the material's broader use in clinical practice from a microbiological perspective. This ceramic has demonstrated its ability to compete with zirconium oxide produced by milling techniques in in vitro experiments, but sadly, no in vivo tests have yet been found to determine how this material will function in a patient's oral cavity.

Mechanical characteristics of zirconia produced additively by 3D printing in dentistry - A systematic review with meta-analysis of novel reports.

OBJECTIVES: This study was aimed at comparing the mechanical parameters of ceramics made using the addition and subtraction technique. METHODS: A search was performed on four search engines on 5th April 2023. Quality assessment was performed using study type-specific scales. Where possible, a meta-analysis was performed. SOURCES: Data were extracted from four search engines: PubMed, PubMed Central, Embase, Web of Science, Scopus. STUDY SELECTION: The search strategy identified 686 potential articles. 19 papers were subject to qualitative analysis, and data from 11 papers were meta-analysed. The included studies were of high or medium quality. All included papers were in-vitro studies. No clinical trials were found in the literature. SIGNIFICANCE: Ceramics made in the additive technology in terms of mechanical parameters can compete with ceramics made in the milling technology. There are no clinical studies yet that would indicate the use of this type of material for permanent restorations in patients. Studies presented in the literature vary greatly in terms of study design and reporting of results. The research did not receive external funding.

Comparison of Dental Zirconium Oxide Ceramics Produced Using Additive and Removal Technology for Prosthodontics and Restorative Dentistry-Strength and Surface Tests: An In Vitro Study.

BACKGROUND: The aim of this in vitro study was to determine the mechanical and functional properties of zirconium oxide ceramics made using 3D printing technology and ceramics produced using conventional dental milling machines. METHODS: Forty zirconia samples were prepared for this study: the control group consisted of 20 samples made using milling technology, and the test group consisted of 20 samples made using 3D printing technology. Their surface parameters were measured, and then their mechanical parameters were checked and compared. Density, hardness, flexural strength and compressive strength were tested by performing appropriate in vitro tests. After the strength tests, a comparative analysis of the geometric structure of the surfaces of both materials was performed again. Student's t-test was used to evaluate the results (p < 0.01). RESULTS: Both ceramics show comparable values of mechanical parameters, and the differences are not statistically significant. The geometric structure of the sample surfaces looks very similar. Only minor changes in the structure near the crack were observed in the AM group. CONCLUSION: Ceramics made using additive technology have similar mechanical and surface parameters to milled zirconium oxide, which is one of the arguments for the introduction of this material into clinical practice. This in vitro study has shown that this ceramic can compete with zirconium made using CAD/CAM (Computer-Aided Design and Computer-Aided Manufacturing) methods.