Vertical marginal fit of advanced lithium disilicate crowns: an in- vitro study

Abstract Statement of the problem The clinical performance of ceramic crowns is influenced by overall marginal adaptation. A recently introduced advanced lithium disilicate ceramic requires further evidence compared to conventional lithium disilicate in terms of vertical marginal fit. Purpose of the study To assess the vertical marginal fit of crowns constructed from advanced and conventional lithium disilicate materials. Materials and methods Ten ( n  = 10) ceramic crowns were constructed and randomly assigned to two groups: Group (T) with CEREC Tessera crowns ( n  = 5) and Group (E) with IPS e.max CAD crowns ( n  = 5). Vertical marginal fit was evaluated using a stereomicroscope at 10X magnification both before and after cementation, with twenty equidistant measurement points recorded for each crown. Each crown was cemented to its corresponding natural molar tooth using Totalcem resin cement. Mann-Whitney U test was used to compare the two material groups. Wilcoxon signed-rank test was used to compare between vertical marginal fit before and after cementation ( P  ≤ 0.05). Results The overall vertical marginal fit between the two groups showed no significant difference, whether before or after cementation. However, both groups exhibited a statistically significant decrease in vertical marginal fit after cementation. Conclusion Advanced lithium disilicate shows advantageous properties concerning mean marginal gap values exhibiting comparable performance to IPS e.max CAD. Clinical implications CEREC Tessera demonstrated marginal fit values within clinically acceptable limits, supporting its reliability as a novel chairside material suitable for use in restorative dentistry.