Aim: The marginal and internal fit, fracture strength, and mode of failure of 3rd
printed CAD/CAM provisional crowns were compared to those of direct provisional
crowns. Subjects and Methods; Following tooth preparation guidelines upper right
first premolar Farasco tooth. 3rd printed Polyphenylene sulfone (PPSU), milled CADCAM Polyetheretherketone (PEEK) and ProtempTM4 manually fabricated were the
materials tested (control group). The crowns were divided into three groups (n=20):
Groups 1, 2, and 3: Each crown was examined for marginal and internal fit, fracture strength, and failure mode. In a universal test machine, the maximum force at
fracture (Fmax) was measured, and the mode of failure was reported at 0.5 mm/min.
ANOVA, chi-squared test, and Tukey's tests (p 0.05). Results: the average marginal
gap of PEEK(Polyetheretherketone) CAD-CAM was less than the 3rd printed PPSU
(Polyphenylene sulfone) and direct fabrication Protemp™4, PPSU 80.64±8.34 µm,
PEEK 60.64±9.54 µm, and Protemp4 120.64±32.34 µm. This indicated a statistically significant difference in the marginal gap distances between all groups (p < 0.001).
The average internal gap value for each group was: PPSU 155.32±20.56 µm, PEEK
123.45±16.11 µm, and Protemp™4 260.34±34.45 µm. There was a statistically significant difference in fracture strength between all classes. (p < 0.001). Each group's
average fracture strength was: PPSU 657.43±23.43 N, PEEK 870.45±18.87 N, and
Protemp™4 427.34±25.43 N. Conclusion. CAD/CAM PEEK temporary crowns and
the 3rd printed PPSU material exhibited significantly higher fracture strength and less
marginal and internal gap measurements than conventionally fabricated Protemp™
4 resins after the aging regimen.