Vertical misfit of laser-sintered and vacuum-cast implant-supported crown  copings luted with definitive and temporary luting agents.
OBJECTIVE
This study aimed to evaluate the vertical discrepancy of implant-supported crown structures constructed with vacuum-casting and Direct Metal Laser Sintering (DMLS) technologies, and luted with different cement types.


METHODS
Crown copings were fabricated using: (1) direct metal laser sintered Co-Cr (LS); (2) vacuum-cast Co-Cr (CC); and (3) vacuum-cast Ti (CT). Frameworks were luted onto machined implant abutments under constant seating pressure. Each alloy group was randomly divided into 5 subgroups (n = 10 each) according to the cement system utilized: Subgroup 1 (KC) used resin-modified glass-ionomer Ketac Cem Plus; Subgroup 2 (PF) used Panavia F 2.0 dual-cure resin cement; Subgroup 3 (RXU) used RelyX Unicem 2 Automix self-adhesive dual-cure resin cement; Subgroup 4 (PIC) used acrylic/urethane-based temporary Premier Implant Cement; and Subgroup 5 (DT) used acrylic/urethane-based temporary DentoTemp cement. Vertical misfit was measured by scanning electron microscopy (SEM). Two-way ANOVA and Student-Newman-Keuls tests were run to investigate the effect of alloy/fabrication technique, and cement type on vertical misfit. The statistical significance was set at α = 0.05.


RESULTS
The alloy/manufacturing technique and the luting cement affected the vertical discrepancy (p < 0.001). For each cement type, LS samples exhibited the best fit (p < 0.01) whereas CC and CT frames were statistically similar. Within each alloy group, PF and RXU provided comparably greater discrepancies than KC, PIC, and DT, which showed no differences.


CONCLUSIONS
Laser sintering may be an alternative to vacuum-casting of base metals to obtain passive-fitting implant-supported crown copings. The best marginal adaptation corresponded to laser sintered structures luted with glass-ionomer KC, or temporary PIC or DT cements. The highest discrepancies were recorded for Co-Cr and Ti cast frameworks bonded with PF or RXU resinous agents. All groups were within the clinically acceptable misfit range.
Department of Buccofacial Prostheses, Faculty of Odontology, Complutense University of Madrid, Madrid, Spain. raquel.castillo@odon.ucm.es
Raquel
R
Castillo-de-Oyagüe
Andrés
A
Sánchez-Turrión
José-Francisco
JF
López-Lozano
Alberto
A
Albaladejo
Daniel
D
Torres-Lagares
Javier
J
Montero
Maria-Jesús
MJ
Suárez-García
D003442:Crowns; D003738:Dental Cements; D059605:Dental Implant-Abutment Design; D007834:Lasers; D014618:Vacuum
D003738:Dental Cements