The aim of this study was to evaluate the clinical performances of Edelweiss prefabricated veneers and direct resin composite restorations (Ceram-X Duo SphereTec) performed with U- veneer transparent templates used for anterior diastema closure and tooth reshaping over 3-year.

The study protocol was approved by the Ethical Committee of Ege University, Izmir, Turkey (18-11.1T/15; 28.11.2018). 21 patients (1 male, 20 females, mean age: 35) with aesthetic complaints on their anterior teeth were treated with 74 restorations. 21 volunteer individuals without systemic disease were included in the study. Patients were randomly selected for each group. In Group 1; 38 teeth (10 patients) were restored with Edelweiss prefabricated veneers (Edelweiss Dentistry) in combination with Edelweiss nanohybrid resin composite (Edelweiss Dentistry) and Prime\&Bond Universal (Dentsply Sirona) adhesive system. In Group 2; 36 teeth (11 patients) were restored with Ceram-X Duo SphereTec (Dentsply Sirona) resin composite in combination with U- veneer (Ultradent) transparent templates and Prime\&Bond Universal adhesive systems.

Periodontal treatments, fillings, and bleaching treatments were performed, if necessary, before any veneer treatment. For the pre-treatment records; 3 photographs (smile, anterior occlusion, and upper anterior teeth alone) were taken from each patient. The "Button Try" technique was used for color selection in both groups. Edelweiss sizing guide was used for size selection in Group 1. U-Veneer (Ultradent) transparent templates were tried on the labial surfaces of teeth to select the correct size in Group 2. Then teeth were cleaned with non-fluoride pumice (Cleanic; Kerr Dental, ABD) using a polishing brush. Isolation of the teeth and retraction of the lips were achieved with a disposable mouth retractor (OptraGate, Ivoclar Vivadent). Prefabricated veneers were prepared for the cementation process in Group 1. Then the labial surfaces were etched using 36% phosphoric acid for 30 s. The etched surfaces were rinsed for 30 s and dried. Prime\&Bond Universal (Dentsply Sirona) adhesive system was applied on the labial surfaces of the teeth in accordance with user instructions in both groups. In Group 1; Edelweiss nano hybrid resin composite was placed on the inner surfaces of the prefabricated veneers before being applied on appropriate teeth. Then the restorations were light-cured for 40 s from each surface (D-Light Pro, GC). In Group 2; Ceram-X Duo SphereTec (Dentsply Sirona) nanohybrid resin composite with dentin color was placed on the labial surfaces of the teeth and light-cured (D-Light Pro, GC). After that layer, Ceram-X Duo SphereTec (Dentsply Sirona) enamel shades were placed on the inner surface of the transparent template and pressed against the labial surface of the tooth. After the removal of the excess materials, the resin composite veneer was light-cured for 20 s from each surface. Then the transparent template was removed.

In both groups; gingival borders were adapted with contouring and polishing discs (Super-Snap Rainbow Technique Kit, SHOFU). Then proximal surfaces were polished using proximal sandpaper strips. Occlusion was checked for premature contacts. Two calibrated observers who were blinded to the objective of this study performed the evaluations. Color match, marginal adaptation, marginal discoloration, anatomic form, retention, secondary caries, and gloss retention were the properties evaluated for the restorations at baseline, 6, 12, 24, and 36 months using Modified Ryge Criteria (USPHS Criteria). Data were evaluated using the Chi-Square and Fisher's Exact tests (p=0.05).