Marginal and internal fit of zirconia crowns fabricated by advanced custom jetting and digital intraoral scanning: An in vitro study

Abstract

Statement of problem

Advanced custom jetting (ACJ) is an innovative high-precision 3-dimensional (3D) printing process for zirconia crowns, and digital scanning has gained widespread adoption in dentistry. However, the impact of different recording methods (conventional silicone versus digital scanning) on the marginal and internal fit of ACJ-fabricated zirconia crowns after cementation under simulated clinical conditions on extracted teeth remains unclear.

Purpose

The purpose of this in vitro study was to evaluate and compare the effects of silicone impressions and digital scanning, as well as subtractive manufacturing (SM) and ACJ, on the marginal and internal fit of zirconia crowns under simulated clinical conditions.

Material and methods

Thirty-six mandibular first molars were prepared by a prosthodontist and randomly assigned to 3 groups. The crowns were fabricated using 3 methods: silicone impression combined with SM (SS), digital scanning combined with SM (DS), and digital scanning combined with ACJ (DA). After cementing the crowns, the specimens were placed in a water bath for 24 hours. A sectioning technique was used to select and polish the 3 central sections of each specimen. Marginal, axial, angular, and occlusal fits were measured and analyzed using the MANOVA statistical test (α=.05).

Results

Statistically significant differences in marginal, angular, and occlusal discrepancies were observed among the 3 groups (P<.001). The DA group exhibited the lowest marginal (47.5 ±17.2 µm), angular (68.8 ±23.2 µm), and occlusal (87.7 ±40.1 µm) discrepancies, while the SS group displayed the highest values (79.9 ±31.2 µm, 144.4 ±56.9 µm, and 206.7 ±63.7 µm, respectively). For axial discrepancies, the DA group showed significantly lower values (52.9 ±16.8 µm) compared with the SS group and DS group (P<.001). These findings indicate that the DA group achieved better marginal and internal fit than the SS group and the DS group.

Conclusions

ACJ demonstrated better marginal and internal fit than SM techniques. The DA group consistently exhibited the lowest discrepancy values, underscoring the combined potential of ACJ and digital scanning in achieving high precision zirconia crowns.