• Pakwan Varapongsittikul, D.D.S.
• Top Chitkraisorn, D.D.S.
• Nichamon Chaianant, D.D.S., MSc, Ph.D.
• Terawat Tosiriwatanapong, D.D.S., DScD & CAGS (Prosthodontics)
• Boonsong Prateepsawangwong*, D.D.S., MDS (Prosthodontics)

To compare fracture resistance of endodontically treated maxillary premolars restored with
ceramic restorations using three retentive techniques. Forty maxillary premolars were randomly
selected as a control (Group 1), composite core/crown (Group 2), fiber-reinforced composite post/
composite core/crown (Group 3) and endocrown (Group 4). All restorations were thermo-cycled and
subjected to vertical loading. Fracture load and fracture modes were analyzed. The results showed that
Group 3 recorded a significantly highest fracture load (2304 ± 737 N). Pairwise comparisons showed
no significant difference between Group 2 (1229 ± 303 N) and group 4 (1609 ± 395 N). Type of
coronal-radicular retention was significantly associated with fracture mode (p = 0.002). All fractures
in Group 4 were non-restorable. After adjusting for fracture load (limited to Groups 1-3),
logistic regression displayed no significant differences in fracture mode between Groups 1, 2 and 3.
In conclusion, the all-ceramic crowns presented the highest fracture strength when fiber-reinforced
composite posts and composite cores were included in the restoration of endodontically treated
maxillary premolar.

(CU Dent J. 2019;42:65-76)