Digital Evaluation of Marginal Adaptation of 3D-Printed and Milled Endocrown Restorations: An In Vitro Study

The aim of this in vitro study was to evaluate the effect of materials on the marginal adaptation of endocrowns.

Ninety-six extracted mandibular molars were prepared and divided into three groups (n=32) based on the restorative materials used. Endocrowns were fabricated using an additive manufacturing technique with a 3D-printed ceramic-filled hybrid resin (VarseoSmile® TriniQ®, [VST], BEGO) and a subtractive manufacturing technique using either glass-ceramic (Initial LiSi Block, [LDS], GC) or nano-ceramic hybrid blocks (Grandio Blocs, [GB], Voco). The marginal gap (MG) was evaluated using the digital replica technique. Dimensional discrepancies were evaluated by digitally aligning the master and silicone replica scans using the best-fit algorithm of the analysis software (OraCheck, Dentsply Sirona). The measurements were repeated three times, and the values were averaged. Data were statistically evaluated using two-way analysis of variance (ANOVA) and the Bonferroni test, with a significance level of p<0.05.

Among all groups, VST exhibited the lowest MG values, differing significantly from the two milling groups (p<0.001), whereas no significant difference was observed between GB and LDS (p>0.05).

Although all materials demonstrated clinically acceptable marginal adaptation, the additively manufactured restorations exhibited significantly narrower marginal gaps compared to the milled counterparts, suggesting a potential advantage for endocrown longevity.