Effect of manufacturing trinomial and restoration thickness on the fabrication trueness, fit, and margin quality of additively manufactured resin-based ultrathin laminate veneers.

Abstract

Objective: To evaluate the effect of the manufacturing trinomial (manufacturing technology, three-dimensional printer, and material) and restoration thickness on the fabrication trueness, fit, and margin quality of additively manufactured resin-based ultrathin laminate veneers (LVs) by comparing to those produced subtractively.

Methods: Reference LVs were designed from the scan files of two identical maxillary central incisor typodonts prepared for 0.3 mm and 0.5 mm LVs. LVs were manufactured additively with resins of different compositions, either using a tilting stereolithography (Irix Max [AM-IX] and Irix Plus [AM-IP]) or a digital light processing printer (VarseoSmile Crown Plus [AM-VS] and Tera Harz TC- 80DP [AM-GR]), and subtractively (Tetric CAD [SM-TC]) (n=10). All LVs were digitized to evaluate their fabrication trueness and fit. The margin quality was assessed through visual examination. The trueness and fit data were analyzed with two-way analysis of variance and Tukey tests, while the chi-squared test was used to evaluate the margin quality (α = 0.05).

Results: The interaction between the main factors and the manufacturing trinomial affected the fabrication trueness and fit, while restoration thickness affected the fit of tested LVs (P ≤ 0.001). AM-IP mostly had the lowest deviations, followed by AM-IX, and mostly had the lowest gaps (P ≤ 0.037). Thinner LVs had lower gaps (P < 0.001). Tested LVs mostly had slightly rough margins with small defects.

Conclusions: LVs fabricated with the tilting stereolithography printer mostly had higher trueness. Using AM-IP or fabricating 0.3 mm LVs improved the fit. Nevertheless, all tested LVs had clinically acceptable fit.

Clinical significance: Ultrathin laminate veneers fabricated with the manufacturing trinomial involving tested tilting stereolithography printer and resins may require less clinical adjustments. In addition, one of the resins (AM-IP) within this manufacturing trinomial or fabricating 0.3 mm laminate veneers may improve the fit.