Reliability evaluation of alumina-blasted/acid-etched versus laser-sintered dental implants

Abstract

Step-stress accelerated life testing (SSALT) and fractographic analysis were performed to evaluate the reliability and failure modes of dental implant fabricated by machining (surface treated with alumina blasting/acid etching) or laser sintering for anterior single-unit replacements. Forty-two dental implants (3.75×10 mm) were divided in two groups (n021 each): laser sintered (LS) and alumina blasting/acid etching (AB/AE). The abutments were screwed to the implants and standardized maxillary central incisor metallic crowns were cemented and subjected to SSALT in water. Use-level probability Weibull curves and reliability for a mission of 50,000 cycles at 200 N were calculated. Polarized light and scanning electron microscopes were used for failure analyses. The Beta (β) value derived from use-level probability Weibull calculation of 1.48 for group AB/AE indicated that damage accumulation likely was an accelerating factor, whereas the β of 0.78 for group LS indicated that load alone likely dictated the failure mechanism for this group, and that fatigue damage did not appear to accumulate. The reliability was not significantly different (p>0.9) between AB/AE (61 %) and LS (62 %). Fracture of the abutment and fixation screw was the chief failure mode. No implant fractures were observed. No differences in reliability and fracture mode were observed between LS and AB/AE implants used for anterior singleunit crowns.

Reliability and failure modes of narrow implant systems

“…The lack of long-term studies reporting on prosthetic survival rates on narrow implants has recently been pointed out [27], which indicates the need of clinical trials that supports previous in vitro evaluation of their performance considering that an important failure mechanism in metals is fatigue [31]. The step-stress accelerated life testing method utilized in the present study consists in testing the samples at higher stress levels in order to accelerate failures, although every sample is subjected to progressively increasing loads which start at low levels before reaching the above mentioned higher levels [21,30,[32][33][34][35]. These failures are distributed over three different profiles allowing statistical predictions for a given load and cycle mission.…”

Direct Metal Laser Sintering Titanium Dental Implants: A Review of the Current Literature

“…The authors concluded that the normalized endurance limits of the tested structures were lower than that of solid titanium (with similar alloy) and that of some other porous titanium structures manufactured using other techniques [ 54 ]. Almeida and colleagues [ 55 ] investigated the mechanical behaviour of DMLS titanium dental implants. Step-stress accelerated life testing (SSALT) and fractographic analysis were performed to compare the reliability and failure modes of DMLS and sandblasted-acid etched (SAE) implants used for anterior single-unit replacements [ 55 ].…”

“…Almeida and colleagues [ 55 ] investigated the mechanical behaviour of DMLS titanium dental implants. Step-stress accelerated life testing (SSALT) and fractographic analysis were performed to compare the reliability and failure modes of DMLS and sandblasted-acid etched (SAE) implants used for anterior single-unit replacements [ 55 ]. Forty-two standard dental implants (3.75 mm × 10.0 mm) were used; among these implants, 21 were fabricated with DMLS technology while the other 21 were SAE implants.…”

“…The abutments were screwed to the implants and standardized maxillary central incisor metallic crowns were cemented and subjected to SSALT in water. At the end of the study, no differences in reliability and fracture mode were observed between DMLS and SAE implants used for anterior single-unit crowns [ 55 ]. These findings suggested that DMLS technology titanium implants may not affect the implant fatigue endurance [ 55 ].…”