Custo-benefício de diferentes impressoras 3D na Ortodontia

Abstract

When choosing a 3D printer for dental models, cost-benefit should be evaluated. Printed models should be accurate, precise and time efficient, as well as financially accessible. The aim of this study is to compare the accuracy, precision, cost and time required for preparation and printing using different technologies: two DLP (Digital Light Processing) printers, and one FFF (Fused Filament Fabrication) compared to the gold standard (PolyJet). For this study, it was selected 10 intraoral scans of 5 patients. All 10 models were printed as follows: (1) DLP printer Moonray (MR), (2) DLP printer Anycubic (AC) (3) DLP printer Moonray with Anycubic resin (MRA), (4) filament printer UpMini 2 (FFF) and (5) PolyJet printer Objet eden500 (PJ). One of the virtual models was additionally printed four consecutive times on each printer to allow consistency assessment. The original .STL file of each model was superimposed by scanning its respective printed model, generating color maps that allowed the RMS (root mean square) calculation for the comparison of both models. In addition, linear measurements were performed using a digital caliper on 8 different variables: inter-canine distance (ICD), inter-molar distance (IMD), bilateral anteroposterior plane (APP-R and APP-L), bilateral vertical plane (VP-R and VP-L) and bilateral mixed plan (MP-R and MP-L). The Shapiro-Wilk test showed that the data was not normally distributed. Friedman's test with Bonferroni's post hoc test was used to verify if there were differences between the evaluated variables. A difference above 0.4 mm was considered clinically significant for linear measurements. Clinically and statistically significant differences (p <0.05) were observed for the following comparisons: VP-R and VP-L between MR and MRA (p = 0.00), VP-R between FFF and MR (p = 0.01), VP-L between FFF and MR (p = 0.00). For RMS, there were statistically significant differences between: AC and MR (p = 0.00); AC and MRA (p = 0.00); FFF and MR (p = 0.01) and PJ and MR (p = 0.00). For the differences in RMS, no value was above the clinical significancy threshold (0.25mm). When the consistency of the models by the linear measurements was evaluated, a statistically significant difference was observed only in the VP-R variable between FFF and AC (p = 0.00). The same difference was seen for the RMS values in: AC and MR (p = 0.02) and AC and MRA (p = 0.04). The printers produced similar quality results, although Moonray with Anycubic resin showed loss of accuracy and Anycubic has a consistency problem in vertical plane. Among them, PolyJet printing was considered the fastest one, but with the highest cost. FFF printing has a low printer and filament cost, but with considerably longer printing times. In both DLP printers there was a balance, resulting in a good cost-benefit.