Marginal fit of milled versus different 3D-printed materials for provisional fixed dental prostheses: an in vitro comparative study

Abstract

Introduction. Provisional dental prostheses are used as interim restorations to help patients perform oral functions between the time of tooth preparation and the placement of the final restoration. A provisional dental prosthesis should protect the abutment from pulpal and gingival aggressions, adapt correctly to keep healthy gingival tissues, be durable, and have a low price. The purpose of this in vitro study was to compare the marginal adaptation of different types of provisional fixed dental prostheses (PFDP), fabricated using 3D printing technology versus the milling (computer-aided manufacturing [CAM]) technique. Method. Two resin teeth (second premolar and second molar) on a typodont were prepared for three-unit provisional fixed dental prostheses. Thirty models were 3D-printed after a digital model was created using an intraoral scanner. Then, 30 provisional fixed dental prostheses (PFDPs) were made from a variety of materials using a digital design of a 3-unit PFDP and STL files delivered to a milling machine and a 3D printer, respectively. Ten PFDP were milled (CAM), and two sets of ten each, were fabricated with 3D printing technology (stereolithography), using two different materials. All restorations were analyzed under a microscope, and marginal gap was then measured using the software Image J. Results. The milled group presented the best marginal gap values (ranging from 86 to 108 μm) and a median value of 93 μm, followed by GC group with (110-251 μm) with a median value of 205 μm and the PR group with median value of 316.5 μm. Conclusion. According to the findings of this in vitro study, the milling (CAM) technique and SLA technology provides acceptable marginal fit values to fabricate provisional fixed partial dentures.