Reliability and failure modes of internal conical dental implant connections

• Published in: Clinical oral implants research Vol. 24; no. 2; pp. 197 - 202
• Main Authors: Freitas-Júnior, Amilcar C., Almeida, Erika O., Bonfante, Estevam A., Silva, Nelson R.F.A., Coelho, Paulo G.
• Format: Journal Article
• Language: English
• Published: Denmark Blackwell Publishing Ltd 01-02-2013
• Subjects: Crowns; Dental Implants; Dental Prosthesis Design; Dental Prosthesis, Implant-Supported; Dental Restoration Failure; Dental Stress Analysis; Dentistry; fractography; implant-supported prostheses; In Vitro Techniques; Incisor; internal conical interface connection; Maxilla; Microscopy, Electron, Scanning; Reproducibility of Results; step-stress accelerated life testing; Weibull
• ISSN: 0905-7161; 1600-0501
• DOI: 10.1111/j.1600-0501.2012.02443.x

Objective
Biological and mechanical implant‐abutment connection complications and failures are still present in clinical practice, frequently compromising oral function. The purpose of this study was to evaluate the reliability and failure modes of anterior single‐unit restorations in internal conical interface (ICI) implants using step‐stress accelerated life testing (SSALT).
Materials and methods
Forty‐two ICI implants were distributed in two groups (n = 21 each): group AT–OsseoSpeed™ TX (Astra Tech, Waltham, MA, USA); group SV–Duocon System Line, Morse Taper (Signo Vinces Ltda., Campo Largo, PR, Brazil). The corresponding abutments were screwed to the implants and standardized maxillary central incisor metal 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. Differences between groups were assessed by Kruskal–Wallis along with Bonferroni's post‐hoc tests. Polarized‐light and scanning electron microscopes were used for failure analyses.
Results
The Beta (β) value derived from use level probability Weibull calculation was 1.62 (1.01–2.58) for group AT and 2.56 (1.76–3.74) for group SV, indicating that fatigue was an accelerating factor for failure of both groups. The reliability for group AT was 0.95 and for group SV was 0.88. Kruskal–Wallis along with Bonferroni's post‐hoc tests showed no significant difference between the groups tested (P > 0.27). In all specimens of both groups, the chief failure mode was abutment fracture at the conical joint region and screw fracture at neck's region.
Conclusions
Reliability was not different between investigated ICI connections supporting maxillary incisor crowns. Failure modes were similar.