A clinical study comparing digital scanning and conventional impression making for implant-supported prostheses: A crossover clinical trial

Abstract

Statement of problem: The impact of discrepancies between casts produced from digital scans and conventional impressions on the clinical performance of definitive restorations has not been fully investigated.

Purpose: The purpose of this crossover clinical trial was to evaluate the clinical performance of single implant-supported restorations fabricated with the digital scanning technique and computer-aided design and computer-aided manufacturing (CAD-CAM) casts compared with the conventional impression technique and gypsum casts in terms of efficiency, accuracy, and participant preference.

Material and methods: Thirty participants underwent conventional impressions and digital scans of a single implant-supported restoration. Two crowns were fabricated for the same implant with each technique. The time taken for each procedure was recorded. After the accuracy and efficiency analysis of both crowns, the better crown was delivered. A questionnaire was used to assess participant preference and comfort with the techniques. The Wilcoxon signed-rank test was used to compare the time measurements, and multiple comparisons were performed using the Bonferroni method. The chi-square test was used to compare the implant locations of delivered crowns (α=.05).

Results: The total time for the conventional impression technique was 14.16 minutes, while that for the digital scanning technique was significantly less at 11.28 minutes (P<.001). Remake times were 0.56 minutes for conventional impressions and 2.27 for digital scans, also significantly different (P<.001). The adjustment time taken in delivering the crowns was 4.35 minutes for conventional impressions and 3.78 minutes for conventional impressions, which was not statistically significant (P=.940). Of the crowns chosen for delivery, 46.7% were from conventional impressions and 53.3% from digital scans. Participants preferred the digital scanning technique (89%) to the conventional impression technique (11%).

Conclusions: The digital scanning technique was more efficient than the conventional impression technique for single implant-supported restorations. Digital scans and CAD-CAM implant casts had accuracy comparable with that of conventional impressions and gypsum casts. Most participants preferred digital scans to conventional impressions.