Comparação do método digital e convencional para moldagem e confecção de próteses unitárias sobre implantes: estudo clínico randomizado avaliando o tempo de trabalho

Abstract

With the advancement of digital dentistry, intraoral scanning has gained popularity due to advantages such as reduced working time, elimination of material storage, and greater patient comfort. However, it still has a high cost and requires a learning curve. The aim of this study was to compare conventional and digital impression techniques used for the fabrication of single-unit implant prostheses in terms of working time for both impressions and crown adjustments, as well as to evaluate cost and patient comfort. This was a randomized equivalence clinical trial with parallel groups, designed following the CONSORT 2010 Statement, in which two groups were evaluated: patients who underwent conventional impression with heavy and light addition silicone (Variotime, Kulzer) and patients who underwent digital impression using the intraoral scanning technique (Trios 3 Wired intraoral scanner, Shape). The primary outcome variables were the time taken to perform each impression technique and the time taken to adjust the crowns until they were properly seated. As a secondary outcome, cost of technique based on the Time-Driven Activity-Based Costing methodology and patient comfort were evaluated using an adapted Visual Analogue Scale questionnaire. For statistical analysis, the ShapiroWilk test and the non-parametric Mann-Whitney test (p<0.05) were used. The patients were previously selected from the Dental Prosthesis Extension Project at the Federal University of Pelotas (UFPel). They underwent randomization into “Conventional Impression” and “Digital Impression” groups. A total of 22 implants were randomized, with 21 impressions and 18 crowns adjusted. The average molding time using the conventional technique was 35 minutes, while the average molding time using the digital technique was 6 minutes, showing a statistically significant difference between the groups (p=0.0001). The average time to adjust the crowns fabricated using the conventional impression was 25 minutes, while for the digital technique it was 12 minutes. Despite the difference, it was not statistically significant (p=0.3743). The cost for conventional impressions was 7.20 USD and for the cost of digital molding to equal that of conventional molding, 483 digital moldings are required per year. However, the digital technique is 5.3x faster. Regarding the questionnaire on comfort with the molding technique used, there was no statistically significant difference between the groups. It can be concluded from these results that the clinical time required to manufacture a single implant-supported prosthesis using the digital technique is much shorter than using the conventional technique, and it also provides greater comfort to the patient in some parameters. However, due to the need to perform a large number of scans for the cost to match that of conventional impression techniques, if the clinician does not have a high demand for scanner use, this tool appears to be economically disadvantageous in a five-year projection based solely on the parameters analyzed.