Objectives
To characterise the mechanical properties of the machinable polymers Pekkton® (Cendres-Meteaux, Biel/Bienne, Switzerland), Lava Ultimate® (3MESPE, Seefeld, Germany), Vita Enamic® (Ivoclar Vivadent, Schaan, Liechtenstein) and the ceramic IPS e.Max Press® (Ivoclar Vivadent, Schaan, Liechtenstein). To determine the structural integrity of full coverage crowns fabricated from these materials.
Methods
The following tests were conducted: Biaxial flexural strength (BFS) using the piston on 3 balls jig (n = 10); Vickers Hardness (VH) 10 indentations per sample with 10 kg load & 20 s dwell time (n = 5); Hygroscopic Expansion Change (HEC) in artificial saliva over 68 days (n = 5). Structural Strength (SS) of teeth analogues (n = 20) restored with monolithic crowns from the four materials. Mean values and standard deviations for BFS, VH, HEC and SS tests were calculated and compared using one-way ANOVA with post-hoc Tukey’s test at a level of 5% significance.
Results
BFS: IPS e.Max Press® (317 MPa ± 37 MPa), Pekkton® (227 MPa ± 18 MPa), Lava Ultimate® (145 MPa ± 18 MPa) and Vita Enamic® (137 MPa ± 7 MPa) with a significance between groups of p < 0.0001. VH: IPS e.Max Press® (5064 MPa ± 131 MPa), Vita Enamic® (1976 MPa ± 12 MPa), Lava Ultimate® (924 MPa ± 27 MPa) and Pekkton® (445MPa ± 21 MPa) with a significance between groups of p < 0.0001. HEC (%vol change): Pekkton® (0.14% ± 0.14%), Vita Enamic® (0.38% ± 0.16%) and Lava Ultimate® (1.06% ± 0.17%). SS for full-coverage crowns: Pekkton® (2037 N ± 49 N no fracture), IPS e.Max Press® (1497 N ± 165 N), Lava Ultimate® (1476 N ± 142 N) and Vita Enamic® (1127 N ± 108 N).
Significance
The properties investigated suggest that full coverage monolithic PEKK crowns possess adequate mechanical and physical properties for use in the posterior region of the mouth. These results must be considered alongside other data including clinical studies.
CORE (COnnecting REpositories)
CORE (COnnecting REpositories)