Acurácia do scanner intraoral para a fabricação de infraestruturas em próteses totais fixas implantossuportadas com ajuste passivo: uma revisão sistemática

Abstract

Introduction: With the introduction of CAD/CAM technology (computer-aided design/computer-aided manufacturing) and intraoral scanners, it has become possible to obtain prosthetic works with greater precision and less working time. However, when it comes to the digitalization of full edentulous arches rehabilitated with multiple implants to obtain infrastructures for implant-supported fixed complete dentures with passive fit, it is seen as a challenge, given the absence of anatomic reference, angulation and distance between the implants. Objective: To evaluate the accuracy of the intraoral scanner for the fabrication of infrastructures with passive adjustments through a systematic review. Material and Methods: This systematic review followed the PRISMA protocol and was registered on the PROSPERO platform. A search was performed in MEDLINE/PubMed, Scopus, Web of Science and the Cochrane Library including all articles published up to December 2021. In addition, a gray literature search (Expertscape, Google Scholar and OpenGrey) was added. All selected studies evaluated the passivity and/or unsuitability of frameworks for implant-supported fixed complete dentures manufactured by digital workflow using an intraoral scanner and compared with the conventional workflow. A quality assessment of the included studies was performed based on the adapted Critical Appraisal Skills program (CASP) and MINORS (Methodological Index for Non-Randomized Studies). Results: Four studies were included, two randomized controlled trials and two in vitro studies. Three studies performed splinting for scanning, one using the conventional technique only, one using the digital technique and one using both techniques. Passivity was evaluated by the Sheffield test in in vitro studies and mean values of misfits between < 30 µm and < 23 µm were observed in the digital method. In clinical studies, it was observed that all infrastructures made by digital flow were passive, showing a survival rate of implants and prostheses made around 100%, with no statistically significant differences regarding peri-implant bone loss between flow of conventional and digital work. In these clinical studies, they also observed that digital procedures take less time to perform when compared to conventional procedures and the difference was statistically significant (p < 0.001). Conclusion: There is still not enough scientific evidence to indicate the most accurate technique, but the results of the studies present in the literature so far show that the digital technique using the intraoral scanner can be a promising technique, since clinically acceptable levels of misfit can be obtained by this method, and may be a valid and faster treatment option for the rehabilitation of complete arches.