Effect of pulp chamber depth on failure load and mode of failure of CAD/CAM endocrowns

The present study aimed to investigate the effect of pulp chamber depth on the failure load and mode of failure of CAD/CAM endocrowns.

Thirty mandibular molars were sectioned above the cementoenamel junction (CEJ), followed by root canal treatment. Teeth were sectioned at a level of 1.5 mm above the CEJ, arranged from the lowest to the highest depths, and divided into three groups (n = 10): group SE: Shallow pulp chamber (1.42 to 2.17 mm); group IE: Intermediate pulp chamber (2.25 to 3.17 mm); group DE: Deep pulp chamber (3.33 to 5.17 mm). CAD/CAM endocrowns were fabricated by milling lithium disilicate ceramic blocks and were cemented using resin cement. Teeth were embedded in acrylic resin at 2 mm below the CEJ, and a compressive load was applied to create a 45-degree angled functional loading simulation until the occurrence of failure.

The mean failure loads were highest in group DE (1893.75 ± 496.08 N) compared with groups IE (1103.71 ± 254.59 N) and SE (1084.63 ± 240.92 N), with statistically significant differences between group DE and both groups IE and SE (P < 0.001). Pearson correlation coefficient (PCC) revealed a strong positive correlation between the pulp chamber depth and failure load of the endocrowns. The failure mode for all samples was catastrophic failure.

The pulp chamber depth affected the failure load of the teeth restored with endocrowns. The failure loads were higher in teeth with a greater pulp chamber depth. (Int J Comput Dent 2023;26(1): 31-0; doi: 10.3290/j.ijcd.b3818295).