To compare the accuracy of digital impression and conventional impression for complete-arch implant-supported fixed prosthesis

The Intraoral scan is digital optical scan method, that has advantages such as being more comfortable, easy to transfer, and full digital workflow. Conventional impression using silicon rubber and gained stable accuracy of impression. This study aims to compare the accuracy of two methods.

Inclusion Criteria:

• Age 18-70 years old (including 18 and 70 years old);
• The patient's maxilla or mandible cannot be preserved due to missing teeth or remaining teeth proposed for implant-retained restoration;
• The patient's missing teeth area is available for placement of 4-6 implants;
• Completion of osseointegration of the patient's implants after implant surgery;
• The patient has at least 2 mm width of keratinized mucosa in the remaining alveolar ridge;
• The patient voluntarily participates in the trial and signs an informed consent form

Exclusion Criteria:

• The patient has a severe gag reflex;
• The patient has an intermaxillary distance of less than 20 mm in the posterior region;
• The distance between the two implants is less than 10 mm;
• Implants fitted with composite abutments with the abutment screw holes penetrating at an angle greater than 60 degrees to the alveolar ridge;
• Other patients judged by the investigator to be unsuitable for inclusion