scholarly journals Failure Load and Fatigue Behavior of Monolithic Translucent Zirconia, PICN and Rapid-Layer Posterior Single Crowns on Zirconia Implants

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1990
Author(s):  
Frank A. Spitznagel ◽  
Sara Röhrig ◽  
Robert Langner ◽  
Petra C. Gierthmuehlen

This laboratory study aimed to evaluate the thermo-mechanical fatigue behavior and failure modes of monolithic and rapid-layer posterior single-crowns (SCs) supported by zirconia implants. Methods: 120 all-ceramic crowns supported by one-piece zirconia implants (ceramic.implant; vitaclinical) were divided into five groups (n = 24 each): Group Z-HT: 3Y-TZP monolithic-zirconia (Vita-YZ-HT); Group Z-ST: 4Y-TZP monolithic-zirconia (Vita-YZ-ST); Z-XT: 5Y-TZP monolithic-zirconia (Vita-YZ-XT); Group E: monolithic-polymer-infiltrated ceramic network (PICN,Vita-Enamic); Group RL (rapid layer): PICN-“table-top” (Vita-Enamic), 3Y-TZP-framework (Vita-YZ-HT). Half of the specimens of each group (n = 12) were exposed to fatigue with cyclic mechanical loading (F = 198N, 1.2-million cycles) and simultaneous thermocycling (5–55 °C). Single-load-to-failure testing (Z010, Zwick) was performed for all specimens without/with fatigue application. Data analysis was performed using ANOVA, Tukey’s post-hoc test, two-sample t-test and Bonferroni correction (p < 0.05). Results: All specimens survived fatigue exposure. Significant differences in failure loads were detected among groups (p ≤ 0.004). Materials Z-HT and Z-ST showed the highest failure loads followed by Z-XT, RL and E. The influence of fatigue was only significant for material RL. Conclusions: All types of tested materials exceeded clinically acceptable failure load values higher than 900N and can be recommended for clinical use. Z-HT and Z-ST appear to be highly reliable towards fatigue. Rapid-layer design of PICN and YZ-HT might be an interesting treatment concept for posterior implant SCs.

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
Elif Yeğin ◽  
Mustafa Hayati Atala

Abstract Background Present study compared the failure load of CAD/CAM-manufactured implant-supported crowns and the stress distribution on the prosthesis-implant-bone complex with different restoration techniques. Methods The materials were divided into four groups: group L-M: lithium disilicate ceramic (LDS, monolithic), group L-V: LDS ceramic (veneering), group ZL-M: zirconia-reinforced lithium silicate ceramic (ZLS, monolithic), group ZL-V: ZLS ceramic (veneering). Crown restorations were subjected to load-to-failure test (0.5 mm/min). Failure loads of each group were statistically analyzed (two-way ANOVA, post hoc Tukey HSD, α = 0.05). Finite element analysis (FEA) was used to compare the stress distribution of crown restorations. Results Group L-M had the highest failure load (2891.88 ± 410.12 N) with a significant difference from other groups (p < 0.05). Although there was a significant difference between group ZL-M (1750.28 ± 314.96 N) and ZL-V (2202.55 ± 503.14 N), there was no significant difference from group L-V in both groups (2077.37 ± 356.59 N) (p > 0.05). Conclusions The veneer application had opposite effects on ceramics, increased the failure load of ZLS and reduced it for LDS without a statistically significant difference. Both materials are suitable for implant-supported crowns. Different restorative materials did not influence the stress distribution, but monolithic restorations reduced the stress concentration on the implant and bone.


2021 ◽  
Vol 11 (5) ◽  
pp. 2129
Author(s):  
Hattanas Kumchai ◽  
Patrapan Juntavee ◽  
Arthur F. Sun ◽  
Dan Nathanson

Background: A variety of veneering options to zirconia frameworks are now available. The purpose of this study is to evaluate the effect of veneer materials, veneering methods, cement materials, and aging on the failure load of bilayered veneer zirconia. Material and methods: Zirconia bars (20 × 4 × 1 mm) were veneered to 2 mm total thickness (n = 10/group). Veneering method groups included: 1. Hand-layered feldsparthic porcelain (VM = Vita VM9, Vident) and fluorapatite glass–ceramic (CR = IPS e.max Ceram, IvoclarVivadent); 2. Pressed feldspathic porcelain (PM = Vita PM9, Vident) and fluorapatite glass–ceramic (ZP = IPS e.max ZirPress, IvoclarVivadent); 3. CAD-/CAM-milled feldspathic ceramic (TF = Vitablocs Triluxe Forte, Vident) and lithium-disilicate glass–ceramic (CAD = IPS e.max CAD, IvoclarVivadent). CAD/CAM veneers were either cemented with resin cements (P = Panavia21, KurarayDental), (R = RelyX Ultimate, 3M ESPE), (M = Multilink Automix, Ivoclar Vivadent) or fused with fusion glass–ceramic (C = CrystalConnect, IvoclarVivadent). A three-point bending test (15 mm span, zirconia on tension side) was performed on Instron universal testing machine (ISO 6872) recording load-to-failure (LTF) of first veneer cracks or catastrophic failure. For group VM, PM, TF-M, TF-C, CAD-M, CAD-C, ten more bars were prepared and aged with cyclic loading (100,000 cycles, 50% LTF) and thermocycling (2000 cycles) before testing. Data were analyzed by ANOVA, Tukey HSD post hoc tests, and t-test (α = 0.05). Zirconia veneered with IPS e.max CAD by fusing had significantly higher failure load compared with zirconia veneered with other veneering materials. (p ≤ 0.05). For cemented veneers, the cement type had a significant effect on the failure load of the veneer zirconia specimens. Specimens cemented with Panavia 21 had a lower resistance to loading than other cements. The aging experiment revealed a significant difference in failure load between non-aged and aged bars in groups VM and PM, but not in the groups with CAD-/CAM-milled veneers. In conclusion, veneer materials, veneering methods, and cement materials have a significant effect on the failure load of bilayered veneer zirconia. CAD-/CAM-milled veneer zirconia is not susceptible to aging performed in this study.


2021 ◽  
Vol 13 (5) ◽  
pp. 269
Author(s):  
Lea Sophia Prott ◽  
Frank Akito Spitznagel ◽  
Estevam Augusto Bonfante ◽  
Meike Anne Malassa ◽  
Petra Christine Gierthmuehlen

Author(s):  
Sarah Blender ◽  
Jochen Mellinghoff ◽  
Sebastian Gröller ◽  
Sigmar Schnutenhaus ◽  
Katharina Kuhn ◽  
...  

2019 ◽  
Vol 69 (3) ◽  
pp. 280-289
Author(s):  
Jaspreet Singh ◽  
Kulwinder Singh ◽  
J. S. Saini

The present work deals with the investigations on the joint efficiency and the joint stiffness of the single lap bolt joint made of two dimensional woven glass fibre reinforced composite materials. The effect of joint geometry, bolt pretension and washer has been determined on the bolt joint performance. To estimate the effect of geometric parameters; the edge-to-hole diameter (e/d) and width-to-hole diameter (w/d) ratios are varied from 3 to 4 and 3 to 5, respectively. To study the worst loading conditions; the bolt pre-tension is set to zero, whereas 5 Nm torque is applied to investigate the joint in fully clamped conditions. Two different sizes of washer i.e., the outer diameter of 12 mm and 16 mm have been studied to estimate the effect of the washer on failure load, joint stiffness, and joint efficiency. Progressive damage analysis has been performed on the single lap bolt joint. Characteristic curve method along with Tsai-Wu failure criteria has been used for the prediction of the failure loads and failure modes. The joint stiffness and the failure load of the joint are increased with the increase of w/d ratios. However, the joint efficiency was negatively influenced by w/d ratio.


2019 ◽  
Vol 12 (4) ◽  
pp. 97-102
Author(s):  
Tyler T. Bilden ◽  
Heather A. Evin ◽  
Benjamin C. Noonan ◽  
Alexander C.M. Chong

Introduction Previous literature demonstrated the importanceof stacking at least three reversing half-hitches on alternating posts(RHAPs) following arthroscopic knot placement. However, RHAPsconstruction involves looping the suture in either an “overhand” or an“underhand” manner as it relates to the post, which may affect knotsecurity. This study investigated the presently unidentified influenceof different stacking combinations of three RHAPs and suture materialon arthroscopic knot security. Methods Four different RHAPs stacking combinations were tiedwith three different suture materials. Ten knots of each configurationwere tied using each suture material, resulting in 120 evaluated knots.A single load-to-failure test was performed. The mode of failure andmean ultimate clinical failure load were recorded. Results Different overhand/underhand stacking combinations ofthree RHAPs had a statistically significant effect on arthroscopicknot strength and security; however, all combinations surpassed theminimum ultimate clinical failure threshold. Knots constructed witheither Force Fiber® or braided fishing line had mean ultimate clinicalfailure loads of greater than 200 N and most commonly failed due tosuture material breakage (100%, 60 - 80% respectively). Conversely,FiberWire® demonstrated lower mean ultimate clinical failure loadsand had a higher incidence of elongated but intact failure (60 - 90%). Conclusion Different overhand/underhand stacking combinationsof three RHAPs yielded an arthroscopic knot capable of secure tissuefixation. A significant effect was observed for suture materials on theknot strength. This study increases our understanding of suitableRHAPs construction following arthroscopic knot placement that canlead to improving the ultimate clinical failure loads of constructedarthroscopic knots observed between orthopedic surgeons.


Author(s):  
Kulwinder Singh ◽  
JS Saini ◽  
H Bhunia ◽  
Jaspreet Singh

The present work aims to increase failure loads of pin joints through nanofillers and metal inserts. Pin joints were prepared from woven glass fiber-reinforced laminates with nanoclay as filler material along with metal inserts fitted in holes. To investigate the effect of nanoclay content, 1–5 wt.% of nanoclay was mixed in epoxy. The increase in tensile strength up to 3 wt.% of nanoclay was observed which was due to increase in the specific surface area of the nanocomposite material. Dispersed nanoclay filler particles act as mechanical interlocking between fiber and epoxy matrix which creates a high friction coefficient. The optimal nanoclay content of 3 wt.% was finally used to prepare nanocomposite laminates. The geometric parameters, i.e. edge distance to hole diameter (E/D) ratio and width to hole diameter (W/D) ratio were varied from 2 to 5 and 3 to 6, respectively. Progressive damage analysis along with Hashin failure criteria was performed to predict failure loads and failure modes in pin joints, numerically. Metal inserts reduced the stress concentration around the hole and redistributed stresses at the pin/hole interface, which eventually increased the ultimate failure load of the joint.


Author(s):  
R R Chang

The deformation and first-ply failure load of an asymmetric laminate composite bicycle handlebar have been studied via both theoretical and experimental approaches. The composite bicycle handlebar tube is fabricated with outer main fibre layers and inner reinforcing fibre layers and is designed to predicted first-ply failure loads. Optimal angle-ply orientations of antisymmetric [θ-θ…]-s laminated tubes designed for maximum stiffness were investigated. A number of laminated composite bicycle handlebars were fabricated and subjected to static transverse bend testing. The first-ply failure loads of laminated composite bicycle handlebars tubes were determined using acoustic emission (AE). The failure modes of the bicycle handlebars were studied, and experimental results were used to verify the theoretical predictions. The experimental results have been proved to be efficient and effective in the theoretical prediction of first-ply failure loads of laminated composite bicycle handlebars.


2017 ◽  
Vol 38 (7) ◽  
pp. 797-801 ◽  
Author(s):  
Mark C. Drakos ◽  
Michael Gott ◽  
Sydney C. Karnovsky ◽  
Conor I. Murphy ◽  
Bridget A. DeSandis ◽  
...  

Background: Chronic Achilles injury is often treated with flexor hallucis longus (FHL) tendon transfer to the calcaneus using 1 or 2 incisions. A single incision avoids the risks of extended dissections yet yields smaller grafts, which may limit fixation options. We investigated the required length of FHL autograft and biomechanical profiles for suture anchor and biotenodesis screw fixation. Methods: Single-incision FHL transfer with suture anchor or biotenodesis screw fixation to the calcaneus was performed on 20 fresh cadaveric specimens. Specimens were cyclically loaded until maximal load to failure. Length of FHL tendon harvest, ultimate load, stiffness, and mode of failure were recorded. Results: Tendon harvest length needed for suture anchor fixation was 16.8 ± 2.1 mm vs 29.6 ± 2.4 mm for biotenodesis screw ( P = .002). Ultimate load to failure was not significantly different between groups. A significant inverse correlation existed between failure load and donor age when all specimens were pooled (ρ = −0.49, P < .05). Screws in younger specimens (fewer than 70) resulted in significantly greater failure loads ( P < .03). No difference in stiffness was found between groups. Modes of failure for screw fixation were either tunnel pullout (n = 6) or tendon rupture (n = 4). Anchor failure occurred mostly by suture breakage (n = 8). Conclusion: Adequate FHL tendon length could be harvested through a single posterior incision for fixation to the calcaneus with either fixation option, but suture anchor required significantly less graft length. Stiffness, fixation strength, and load to failure were comparable between groups. An inverse correlation existed between failure load and donor age. Younger specimens with screw fixation demonstrated significantly greater failure loads. Clinical Relevance: Adequate harvest length for FHL transfer could be achieved with a single posterior incision. There was no difference in strength of fixation between suture anchor and biotenodesis screw.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Volker Eras ◽  
Josefine Graffunder ◽  
Norus Ahmed ◽  
Jan C. Brune

Abstract Purpose Meniscus allograft transplantation (MAT) is a possible treatment for patients suffering with pain after meniscectomy. Here, peracetic acid (PAA) sterilised meniscus transplants were investigated on whether they would provide an adequate alternative to fresh-frozen transplants in their viscoelastic and mechanical properties. Methods In this analysis, 31 menisci donors (26 male and 5 female) were included. The average donor age was 49.87 years, ranging from 32 to 65 years. Menisci of matched pairs of knees underwent chemical sterilisation while counterparts were left fresh-frozen. Stiffness and load to failure were determined via suture retention. Further menisci were analysed while attached to the tibial bone block using a novel test device to mimic physiological load distribution. Meniscus relaxation, stiffness and failure loads were determined. Histology and biphasic properties of the menisci were examined and results were analysed using paired t-tests. Results A novel custom built test device allowed the application of physiological loads for suture retention testing and revealed no significant differences between PAA sterilised (14.85 ± 4.46 N/mm, 50.49 ± 17.01 N) and fresh-frozen (18.26 ± 4.46 N/mm, 59.49 ± 21.07 N) regarding stiffness and failure load, respectively. Furthermore, initial 200 N loading showed significantly higher strain in sterilised menisci (18.87 ± 1.56) compared to fresh frozen (13.81 ± 1.04). Load relaxation experiments demonstrated significantly lower relaxation for sterilised menisci (77.71 ± 1.62) compared to fresh-frozen (89.11 ± 1.00, p-value < 0.0001). Conclusion Peracetic acid sterilised human menisci performed equally to fresh-frozen counterparts in a suture retention test and in physiological failure testing providing an adequate alternative. However, meniscus relaxation, biphasic properties and strain were shown to be significantly different between the groups. A common problem of MAT is graft extrusion or shrinkage, therefore the parameters measured here should be considered and may influence meniscus extrusion after transplantation. Level of evidence n/a (experimental study)


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