Vertical misfit of laser-sintered and vacuum-cast implant-supported crown copings luted with definitive and temporary luting agents

Abstract

Objectives. 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. Study Design. 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. Key words:Dental alloy, laser sintering, implant-supported prostheses, vertical discrepancy, vertical misfit.

Annealing of Co-Cr dental alloy: effects on nanostructure and Rockwell hardness

“…During sintering, the atoms in powder particles diffuse across particle boundaries; this fuses the particles together to create a single solid piece 18. DMLS is an additive metal fabrication technology that involves the use of a high-powered Ytterbium (Yb)-fiber optic laser 19. In this technology, metal powder is melted locally with a focused laser beam and fused into a solid part.…”

Combined Treatment with Laser Sintering and Zirconium: A Case Report of Dentinogenesis Imperfecta

“…Also, DMLS is simpler, more precise, and healthier than conventional manufacturing and can be remarkably cost effective [21]. Moreover, DMLS technology affords highly accurate production of fixed partial dentures with ideal marginal fit and excellent mechanical properties [13, 16]. While both Co-Cr and Ti fine powder alloy mixtures can be used to produce metal frameworks for use in dentistry, because of its ease of fabrication, Co-Cr is most commonly used over porcelain restorations.…”

“…The parts are built up additively, layer by layer, each of which is 10–30  μ m thick [14, 15]. DMLS technology affords highly accurate production of fixed partial dentures with fine marginal adaptation and excellent mechanical properties [13, 16]. …”

Precision of fit and retention force of cast non‐precious‐crowns on standard titanium implant‐abutment with different design and height

“…In clinical cases, because of the limited amount of vertical space, these standard titanium abutments have to be shortened to provide sufficient space for the crown framework and the veneering ceramic. In implant abutments that are similar to natural teeth, the retention force of the cement-retained crowns is influenced by various factors such as the height, shape, surface area, diameter, and material properties of the abutment and the crown, as well as the surface treatment methods, fit between the abutment and the crown, cement space thickness and type of luting cement (Boeckler et al 2005;Sadig & Al Harbi 2007;Castillo-de-Oyague et al 2012). Moreover, only a few studies have evaluated the relationship between abutment characteristics, fit and retention forces of implant crowns (Covey et al 2000;Bernal et al 2003;Oyague et al 2009).…”

“…; Sadig & Al Harbi ; Castillo‐de‐Oyague et al. ). Moreover, only a few studies have evaluated the relationship between abutment characteristics, fit and retention forces of implant crowns (Covey et al.…”