To compare the clinical outcomes of anterior porcelain veneer between conventional impression technique using silicone material and intraoral scanning in one year.

Forty patients received anterior teeth veneers from January 2017 to December 2019 in the Department of Prosthodontics and Implantology of Foshan Stomatological Hospital were included in this clinical study, including 14 males and 26 females, with an average age of 40 years old. According to the random number table method, the patients were randomly divided into two groups. Twenty patients (47 teeth) were included in the experimental group where digital impressions with an intraoral scanner and 3D-printed resin models were used. The other 20 patients (40 teeth) were included in the control group where working models were made by the conventional impression with silicone materials and poured with gypsum. The duration of impression taking, restoration adjusting and the patients′ satisfaction were recorded. Clinical evaluations were implemented at one week (baseline) , three and twelve months after cementation of the veneers, including marginal adaptation, restoration integrity, marginal staining, color matching, secondary caries and gingival health. The recorded data were statistically analyzed. In detail, t test was used to compare the duration of impression taking, restoration adjusting between the experimental and control group; Chi square test was used to compare the satisfaction of patients in the process of impression taking and the effect of impression techniques on clinical outcomes of veneers.

The duration of impression taking of the experimental and control group was (1.98 ± 0.17) and (10.93 ± 0.74) min, respectively, which was statistically significant (t = -53.005, P<0.001) . Fifteen patients evaluated the comfort of impression taking as grade Ⅰ, and five patients as grade Ⅱ in the experimental group; in contrast, only five patients evaluated as gradeⅠ, thirteen patients as gradeⅡ, the rest as gradeⅢ in the control group. Compared with the control group, the comfort of the experimental group was higher (χ² = 11.69, P = 0.003) . The adjusting time of the experimental group was (9.28 ± 0.44) min, and that of the control group was (9.42 ± 0.42) min, where there was no significant difference (t = -1.025, P = 0.312) . During 1-year follow-up period, all porcelain veneers performed well of restoration integrity, color matching, and secondary caries. After three months of cementation, two veneers showed slight marginal staining and gingivitis. One year after cementation, the marginal adaptation evaluation of five porcelain veneers decreased, with the probe stuck, but there was no obvious gap. There were ten cases of veneers with slight marginal staining and four cases with mild gingival inflammation. The clinical outcomes of all porcelain veneers were within the clinical acceptable range, and there was no significant difference between the two groups (P>0.05) .

Compared with the conventional technique, the intraoral scanning could achieve a comparable short-term clinical outcome, which seemed a more efficient approach with higher satisfaction from the patients.