Identifying marginal adaptation discrepancies of lithium disilicate crowns using seven different vertical X-ray angulations.

Purpose: To study the effect of different vertical angulations on the ability to radiographically assess vertical marginal discrepancies of lithium disilicate crowns.

Materials and methods: Twenty-one lithium disilicate crowns were fabricated for three different prepared natural teeth: incisor, canine, and premolar. Vertical marginal discrepancies ranging from 0 to 300 µm were intentionally created. The seated crowns were radiographed using seven different vertical angulations, totaling 147 images. Thirty experienced evaluators scored each image for marginal discrepancy, and values were statistically analyzed.

Results: Significant differences in the ability to accurately assess marginal discrepancies from radiographs were observed for the study factors of angulation, tooth type, and degree of marginal discrepancy (p < 0.001).

Conclusions: The radiographic interpretation of the marginal discrepancies of lithium disilicate crowns is significantly affected by the dimension of the marginal discrepancy. Specifically on premolar crowns, it is significantly affected by different vertical angulations of the X-ray beam. When evaluating marginal discrepancy on lithium disilicate crowns radiographically, vertical beam angulation within ±10° to the cemento-enamel junctionCEJ plane is recommended.