Retrospective Clinical Study Of 3D Gel Deposition Zirconia Crowns Fabricated With A Completely Digital Workflow

Objective To apply a new type of completely digital fixed prosthetic workflow in clinic.By using the method of retrospective clinical study,the prosthetic performance and patient satisfaction of 3D gel deposition full contour zirconia crowns fabricated with this completely digital workflow were evaluated,and the clinical efficiency was preliminarily evaluated.Methods By applying intraoral scanning,designing and manufacturing of resin interim crown by CAD/CAM,clinical try-in,digital design modification,and net-shape manufacturing of definitive crown by 3D gel deposition process to establish the completely digital workflow.The clinical records of all patients who had been restored with 3D gel deposition zirconia crowns with a completely digital workflow from July 2016 to December 2019 in the Department of General Dentistry,Stomatological Hospital affiliated to the Zhejiang Chinese Medical University were screened(177 patients,229 crowns).The morphology,occlusion,marginal adaption,and color match of the crowns were evaluated and rated as Alfa,Bravo,and Charlie respectively according to the modified US Public Health Service(USPHS)criteria.The clinical efficiency was preliminary evaluated by the extent of adjustment,including no adjustment,minimal adjustment,and unacceptable.The patient’s satisfaction was obtained by questionnaire in March 2021.Results The morphology and marginal adaption of 229 crowns were rated as Alfa,and the occlusion as Alfa(93.0%),Bravo(6.1%),and Charlie(0.9%),and the color match as Alfa(91.7%),Bravo(6.1%),and Charlie(2.2%).Except for the 2 crowns that needed to be reworked due to unacceptable occlusion,a total of 213(93.8%)crowns required no adjustment during clinical evaluation,11(4.8%)needed minimal adjustment,and 3(1.3%)were deemed unacceptable since they could not meet the clinical requirements through adjustment.A total of 151 valid questionnaires were collected.The general patient satisfaction was 96.0%,and the satisfaction of each sub-item was 96.0%of color,98.7%of morphology,98.7%of chewing capacity,97.4%of pronunciation capacity,98.7%of comfort,and 92.7%of cleaning performance.The crowns of 149 patients were stable,and 2 were loose and re-bonded.150 patients were willing to accept the treatment again and recommend to their friends,while 1 patient was not.80 patients have never had fixed dental prostheses,and 71 patients have had traditional treatment that required impression or doctor’s hand-made interim prostheses.Among those 71 patients,70 were willing to accept the current treatment,and 1 was willing to accept the previous one.Conclusion The 3D gel deposition zirconia crowns fabricated with the completely digital workflow had good prosthetic performance and high patient satisfaction.By applying the digital design modification of CAD/CAM interim crown and precise manufacturing of 3D gel deposition process,the completely digital workflow could reduce the clinical adjustment rate,improve the clinical efficiency,and achieve the concept of precise and efficient prosthetic dentistry.