Conventional and Digital Impressions for Fabrication of Complete Implant-Supported Bars: A Comparative In Vitro Study

Abstract

Obtaining accurate models and well-fitting prostheses during the fabrication of complete implant-supported prostheses has been a significant challenge. Conventional impression methods involve multiple clinical and laboratory steps that can lead to distortions, potentially resulting in inaccurate prostheses. In contrast, digital impressions may eliminate some of these steps, leading to better-fitting prostheses. Therefore, it is important to compare conventional and digital impressions for producing implant-supported prostheses. This study aimed to compare the quality of digital intraoral and conventional impressions by measuring the vertical misfit of implant-supported complete bars obtained using both types of techniques. Five digital impressions using an intraoral scanner and five impressions using elastomer were made in a four-implant master model. The plaster models produced with conventional impressions were scanned in a laboratory scanner to obtain virtual models. Screw-retained bars (n = five) were designed on the models and milled in zirconia. The bars fabricated using digital (DI) and conventional (CI) impressions were screwed to the master model, initially with one screw (DI1 and CI1) and later with four screws (DI4 and CI4), and were analyzed under a SEM to measure the misfit. ANOVA was used to compare the results (p < 0.05). There were no statistically significant differences in the misfit between the bars fabricated using digital and conventional impressions when screwed with one (DI1 = 94.45 µm vs. CI1 = 101.90 µm: F = 0.096; p = 0.761) or four screws (DI4 = 59.43 µm vs. CI4 = 75.62 µm: F = 2.655; p = 0.139). Further, there were no differences when the bars were compared within the same group screwed with one or four screws (DI1 = 94.45 µm vs. DI4 = 59.43 µm: F = 2.926; p = 0.123; CI1 = 101.90 µm vs. CI4 = 75.62 µm: F = 0.013; p = 0.907). It was concluded that both impression techniques produced bars with a satisfactory fit, regardless of whether they were screwed with one or four screws.

The production and materials of mouthguards: Conventional vs additive manufacturing - A systematic review

“…As a first step towards innovation and modernization, sports dentistry has extensively incorporated the use of intraoral scanning to obtain digital models [ 51 ]. This has improved speed [ 52 ], efficiency [ 53 ], and in many cases cost-benefits due to factors such as time savings [ 54 , 55 ], good acceptance in terms of patient comfort [ 56 , 57 ], distortion reduction [ 58 , 59 ], 3D previews [ 60 , 61 ], and data storage and transfer by digital means [ [62] , [63] , [64] ]. The ASTM defines Additive manufacturing as the “process of joining materials to make objects from 3D models data, usually layer upon layer, as opposed to subtractive methodologies, such as traditional machining” [ 99 ].…”