Optimization of full zirconium crowns manufacturing using hybrid digital approach under the sanitary restrictions during Covid-19 pandemic and limited clinical access to intraoral scanner

PURPOSE: To assess clinical optimization of hybrid digital approach for full zirconium crowns manufacturing developed under sanitary restrictions during COVID-19 pandemic considering specific economical interaction of “low budget clinic–high budget dental laboratory”. METHODS: Developed primary approach included following steps: 1) taking analog impression by dental clinician; 2) digitalization of impression by mobile dental technician team outside the dental clinic; 3) transfer of obtained *.stl file to the dental lab; 4) inversion of *.stl file for dental model production with further CAD-CAM manufacturing of zirconium crowns; and 5) delivery of manufactured crowns to the clinic in a non-contact manner. The clinical effectiveness of such an approach was assessed by criteria of clinical time expenditures associated with appropriate crowns fitting and fixation, clinical marginal fit, and risk reduction considering COVID-19 transmission. RESULTS: Analysis of 116 cases demonstrated that in 81.89% of cases, time expenditures associated with appropriate crowns fitting and fixation were not statistically different (p > 0.05) from those needed for crowns manufactured by usual digital protocols. Clinical marginal fit in 70.68% cases was classified as “excellent”, in 21.55% cases – as “good”, and in 7.76% cases – as “appropriate”. Risk reduction of COVID-19 transmission considering a possible way of disease spread varied in the range of 34.61-56.78%. CONCLUSIONS: A proposed approach for full zirconium crowns manufacturing developed specifically under sanitary restrictions during the COVID-19 pandemic optimizes the quality of dental care considering limited clinical access to an intraoral scanner while demonstrating sufficient clinical effectiveness in the means of marginal crowns fit and clinical time expenditures.