Assessment of the Physico-Chemical, Microbial, and Cytotoxic Characteristics of Zirconia Crowns Utilized in Pediatric Dentistry

Zirconia crowns are employed in pediatric dentistry for the complete restoration of anterior and posterior deciduous teeth. They are considered the best option due to their esthetic appeal, high strength, biocompatibility, and resistance to wear and corrosion. This study aims to evaluate the physico-chemical, cytological, and microbial properties of zirconia crowns to determine their biocompatibility, safety for surrounding tissues, and effectiveness in preventing microbial influence on tooth tissue based on their biofilm deposition potential. XRD measurements were conducted to confirm the crown composition. For the microbiological examination, a quantitative assessment of the adhesion capacity of the analyzed strains and the formation of a mixed biofilm was performed using a Zeiss Cell Observer SD confocal microscope. This study used a mixed biofilm containing Streptococcus mutans (ATCC 25175), Lactobacillus rhamnosus (ATCC 9595), Candida albicans (ATCC 90028), and Candida albicans (ATCC 10231) to simulate the oral environment and the possible dynamics created between different types of microorganisms. A direct contact method was used to assess cytotoxic properties. The zirconia crown biomaterial shows a low ability to adhere to specific microorganisms, with L. rhamnosus predominating, indicating low clinical potential for causing inflammation of the tissues surrounding the crown. The cytotoxic properties of the biomaterial were found to be at level 2, indicating moderate cytotoxicity. Their biggest flaws are price and the need for passive fitting, which involves aggressive grinding; this is a potential limitation when it occurs in children, as their cooperation with the treatment can be difficult to guarantee.