Stability of external and internal implant connections after a fatigue test (original) (raw)
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The International journal of oral & maxillofacial implants
This study aimed to evaluate the role of the implant/abutment system on torque maintenance of titanium retention screws and the vertical misfit of screw-retained implant-supported crowns before and after mechanical cycling. Three groups were studied: morse taper implants with conical abutments (MTC group), external-hexagon implants with conical abutments (EHC group), and external-hexagon implants with UCLA abutments (EHU group). Metallic crowns casted in cobalt-chromium alloy were used (n = 10). Retention screws received insertion torque and, after 3 minutes, initial detorque was measured. Crowns were retightened and submitted to cyclic loading testing under oblique loading (30 degrees) of 130 ± 10 N at 2 Hz of frequency, totaling 1 × 106 cycles. After cycling, final detorque was measured. Vertical misfit was measured using a stereomicroscope. Data were analyzed by analysis of variance, Tukey test, and Pearson correlation test (P < .05). All detorque values were lower than the in...
Journal of Prosthodontic Research, 2021
To assess the internal accuracy and mechanical behaviour under cyclic loading after artificial aging of implantsupported crowns restored with original stock abutments and two compatible non-original stock abutments. Methods: Forty-eight original internal hexagon connection implants were connected to different stock abutments. The samples were divided into three groups depending on the manufacturer of the abutment components (one original, two non-originals). Firstly, samples were cross-sectioned and observed by using Scanning Electron Microscope (SEM) to evaluate the internal accuracy in three different implant-abutment interface locations (platform, internal and screw). Further, cyclic fatigue loading was carried out according to the ISO Norm 14801 using dynamic testing machine under sinusoidal loads for 2,000,000 cycles at test frequencies of 2 Hz in air after thermocycling with 10,000 cycles at 5 °C and 55 °C in artificial saliva for aging simulation. Results: Original abutment components presented the highest percentage of surface with tight contact with the implant in the three implant-abutment interfaces studied. Additionally, original configuration showed highest fatigue limit value and fatigue strength exponent (280 N and-0.054) than non-original 1 (225 N and-0.109) and non-original 2 (200 N and-0.101). Conclusion: Original abutment components provide better fit and mechanical results under cyclic loading than nonoriginal configurations. The results obtained in this study seem to suggest that the use of the original stock abutments to implants leads to a more homogeneous load distribution between the components that can influence the long-term success of the restorations.
Fatigue Failure of External Hexagon Connections on Cemented Implant-Supported Crowns
Implant dentistry, 2018
To evaluate the probability of survival and failure modes of different external hexagon connection systems restored with anterior cement-retained single-unit crowns. The postulated null hypothesis was that there would be no differences under accelerated life testing. Fifty-four external hexagon dental implants (∼4 mm diameter) were used for single cement-retained crown replacement and divided into 3 groups: (3i) Full OSSEOTITE, Biomet 3i (n = 18); (OL) OEX P4, Osseolife Implants (n = 18); and (IL) Unihex, Intra-Lock International (n = 18). Abutments were torqued to the implants, and maxillary central incisor crowns were cemented and subjected to step-stress-accelerated life testing in water. Use-level probability Weibull curves and probability of survival for a mission of 100,000 cycles at 200 N (95% 2-sided confidence intervals) were calculated. Stereo and scanning electron microscopes were used for failure inspection. The beta values for 3i, OL, and IL (1.60, 1.69, and 1.23, respe...
Load to failure of different titanium abutments for an internal hexagon implant
The Journal of Prosthetic Dentistry, 2015
Replacing single teeth with implants is a predictable and frequently used treatment. 1-4 A number of restorative options for the single unit implant prosthesis involve screwretained or cement-retained implant crowns. Historically, screw-retained implant crowns were used with good longterm success and were considered the restorative treatment of choice. However, screwretained restorations, especially with less ideally angled implants, are limited. In these situations where ideal placement is not possible, the cement-retained implant crown is the treatment option of choice. 5-8 The main advantage of a screw-retained prosthesis is that of retrievability because prosthetic complications may occur in the lifetime of an implant, such as screw loosening and breakage. 9-13 Cement-retained restorations may be retrievable depending on the type of cement used. Advocates of cement retention cite improved esthetics, more predictable occlusion, and ease of passivity. 14-18 For the Tapered Screw Vent implant (Zimmer Dental), many titanium (Ti) abutment choices are available for a cement-retained restoration, including Atlantis (Dentsply Intl), Glidewell Laboratories, Implant Direct, and Zimmer Dental. Ti abutments vary from