Radiographs were taken and evaluated 1 month and 12 months after restoration placement using a parallel technique, with an X-ray holder for periapical radiographs. They were analysed using a specially designed computer software to perform linear measurements on digital radiographs. The calibration was carried out in the vertical plane of each radiograph by using the known distance of the implant and the distance of several threads in order to ensure correct measurements [19]. Crestal bone changes were determined by measuring, both mesially and distally, the distance from the implant reference point (the neck of the implant) to the margin level of the crestal bone. Bone loss was presented as the worst distal and/or mesial bone level change between 1 month and 12 months after restoration placement.

The patients’ recorded their satisfaction by means of filling out a questionnaire 1 year after restoration placement. The questionnaire included questions or statements to be answered on a 5-point rating scale ranging from “very dissatisfied” and “not in agreement” (score 1) to “very satisfied” and “in agreement” (score 5). The addressed topics were related to aesthetics and appearance, function (eating), sense (“feels like a natural tooth”), speech, and self-esteem. Furthermore, the patients were asked to mark their overall satisfaction with their dental situation at the 1-year evaluation on a 10-point rating scale from 0 to 10, whereby 10 is the highest satisfaction score.

One observer was responsible for the collection and analysis of all the data. The worst score of the clinical and radiographic parameters evaluated per implant was used in the data analysis. Data were presented as frequencies without statistical testing.