Clinical Application Of Full Crown Restoration Made By Digital Replication Registration:Case Reports

Objective: To explore the technical process of digital replication registration in the design of full crown restoration of posterior teeth with tooth defect,measure the occlusal contact area and the number of occlusal points before and after restoration,and evaluate satisfaction of patients and the effect of restoration quality in order: to provide reference and basis for the clinical application of this technique.Method: The patients were selected from the Department of Restoration of Dalian Stomatological Hospital from December 2018 to October 2020.the posterior teeth with tooth defect should be repaired with crown design.Inclusion criteria: Inclusion criteria:The tissues of posterior teeth were defected to varying degrees due to dental caries,dental pulp diseases and other reasons,and the teeth were carried out perfect root canal treatment,resin filling treatment,occlusal adjustment in the mouth for at least 2 weeks as well;The tooth defect area of occlusal surface was small,and the type of defect is non-functional dental cusp / proximal surface,with good filling body,complete buccal,lingual / palatal morphology;The morphology of the opposite teeth and proximal teeth were complete,and periodontal condition was good;There was no oral side functions such as bruxism clenching teeth and no temporomandibular disease,and patients with good compliance,could come back for a check on time.Exclusion criteria: The teeth with adjusted occlusal surface during root canal treatment,loss of occlusal surface shape.and no occlusal contact;large tooth defect area of occlusal surface,no good crown and occlusal surface shape,and abnormal occlusal relationship;poor oral health and poor periodontal conditions;patients with bruxism,clenching teeth and other oral side functions;severe deep overbite and tooth attrition;the patient with poor mental state,who unable to cooperate with scanning;the patients with poor compliance,who could not reexamined regularly.The all-ceramic crowns were fabricated by digital technology using the duplicating method in the included cases,and the follow-up observation and clinical application evaluation were carried out.The course of treatment: 1.General examination and dental specialist examination.2.Communication before operation,making treatment plan,and informing patients of process and expenses.3.The original morphology of tooth before tooth preparation was copied,and the original teeth and opposite teeth were scanned by intraoral scanner(3Shape Trios).The upper and lower jaw occlusal position was scanned at the wide intercuspal position,and the data were saved.4.In strict accordance with the principle of zirconia complete crown preparation,artificial colorimetric and temporary crowns are made after preparation.5.The abutment area was scanned with an intraoral scanner,requiring a clear margin and shoulder.6.The software(3Shape Dental System)was used to design the restoration,the original morphology of tooth before tooth preparation was directly copied using the duplicating method based on biological reconstruction function,and the all ceramic restoration was fabricated using dental milling unit(psychic five-axis cutting machine).Then,the restoration was polished and glazed.7.Try on the restoration,adjust placement,and occlusion,polishing and cementation after normal occlusal and proximal contact.8.The restoration was scanned again,and the occlusal contact data of upper and lower dentition and wide intercuspal position were obtained.9.Regular follow-up visit.After the treatment,the prosthodontics doctor who did not participate in the treatment evaluated and analyzed the restoration,and one week later,the patients filled in the satisfaction questionnaire,then measured and analyzed the data,including the number of occlusal points and the occlusal contact area before and after restoration.Results: A total of 26 patients were included in this study,including 9 males and17 females.The full crown restoration fabricated by digital technology using the duplicating methodh has been properly seating after clinical adjustment,the marginal adaption and proximal contact were suitable,the overall satisfaction of patients is up to98%,and there were no postoperative adverse reactions.The accuracy of the restoration shape was 92.3% in Grade A and 7.79% in Grade B,the proportion of color matching was 88.46% in Grade A,and 11.54% in Grade B;the proportion of marginal adaption was 96.15% in Grade A;3.85% in Grade B,and there was no Grade C.There was no statistical difference in the number of occlusal points between the original teeth and the restoration(P=0.161),the occlusal contact area of dentition before and after restoration(P=0.106)the occlusal contact area before and after tooth preparation(P=0.195),and the occlusal contact area of the proximal teeth(P=0.072).Conclusion: The occlusal contact number and area of the full crown restoration using digital duplicating method are similar to those before tooth preparation,which has better occlusal adaptability,better quality evaluation of the restoration.overall satisfaction and better subjective evaluation of patients.This method can make the design and manufacture of full crown more convenient and quickly,reduce the difficulty of clinical occlusal adjustment,restore the individual occlusion of teeth,and improve the accuracy of full crown restoration.Therefore,it is worthy of clinical application to use the digital fabrication technology of full crown restoration using the duplicating method.