Polyetheretherketone Group Research Articles

Comparative study of some mechanical properties of cobalt chromium and polyether ether ketone thermoplastic removable partial denture clasps: an In-vitro Study

Objective: was to evaluate the retentive force, fatigue resistance and deformity of clasps made from two materials cobalt chromium and poly ether et her ketone (PEEK). Material and Methods: sixteen models were fabricated, each one having lower 1st molar. Models were divided into two groups according to materials, group I (GI) for cobalt chromium (Co-Cr) and group II (GII) for PEEK. Each testing models and its clasps were mounted inside universal testing machine, the retention was measured by applying withdrawal force to it by this machine at 5 mm/min. The Fatigue resistance is measured by the reduction in retention through repeated insertion and removal cycles using robot a chewing simulator. Removal and insertion cycling of clasps was carried out for 360, 730, 1080, 1,440,2,116 and 2,880 cycles (corresponding to 3,6,9,12, 18 and 24 months of simulated clinical use of a RPD) to simulate the fatigue resistance test. Deformity was measured before and after each cycling using a digital micrometer. Statistical analysis was done by 2-way-ANOVA test to detect significance effects of each variable. Results: Retention and fatigue resistance, after 360,730, 1080, 1,440,2,116 and 2,880 cycles totally the difference between Co-Cr and PEEK groups was statistically non-significant (P = 0.0980>0.05) where (Co-Cr > PEEK). Deformation results, regardless to evaluation time, Co-Cr group recorded statistically significant higher deformation mean value than PEEK group (P = 0.008<0.05). Regardless to material group, deformation mean value changed non significantly by time (P = 0.2882> 0.05). Conclusion: PEEK clasps (1.0 mm in cross section diameter) engage 0.50 mm undercut provide sufficient retention nearly similar that of Co-Cr clasps.KeywordsFlexible clasps; Polyether ether ketone, PEEK; Thermoplastic resin; Partial denture.

A comparison of contiguous two-level anterior cervical discectomy and fusion using a structural allograft versus a Polyetheretherketone (PEEK) cage: the results of a three-year follow-up

BackgroundAllografts and polyetheretherketone (PEEK) cages are the two most commonly used materials in anterior cervical discectomy and fusion (ACDF). However, their effectiveness in two-level ACDF remains controversial. The primary aim of this retrospective study was to compare the clinical and radiological outcomes of two-level ACDF with plate fixation using either a structural allograft or a PEEK cage.MethodsFrom 2010 to 2015, 88 consecutive patients underwent two-level ACDF, of whom 53 received an allograft and 35 patients received a PEEK cage. All PEEK cages were filled with local autografts. All clinical outcomes were prospectively collected before and six months and two years after surgery. Clinical efficacy was evaluated using a visual analogue scale for neck pain and limb pain, the Neck Pain and Disability Score, the Neck Disability Index, the Neurogenic Symptom Score, and the Japanese Orthopedic Association score. Radiological outcomes were assessed preoperatively, immediately after surgery, and at the final follow-up.ResultsA preoperative comparison revealed no difference between the two patient groups in terms of age, sex, body mass index, smoking status, preoperative symptoms, operation level, or follow-up (mean = 42.8 months). No differences in the improvements in clinical outcomes were observed between the two groups. Both groups showed significant improvement in mean disc height, segmental height, and segmental lordosis postoperatively. The fusion rate for the PEEK cage was 100% at both levels, while the fusion rate for the allograft group was 98.1% at the cephalad level and 94.2% at the caudad level (p > 0.05). Subsidence at the cephalad level occurred in 22.9% (8/35) of segments in the PEEK group and 7.7% (4/52) of segments in the allograft group (p = 0.057). At the caudal level, a higher incidence of cage subsidence was noted in the PEEK group than in the allograft group [37.1% (13/35) versus 15.4% (8/52)] (p = 0.02). Overall, subsidence was noted in 30% (21/70) of the PEEK group and in 11% (12/104) of the allograft group (p < 0.05).ConclusionThe use of PEEK cages resulted in a higher rate of subsidence in two-level ACDF than the use of allografts. Two-level ACDF using either allografts or PEEK cages resulted in similar clinical outcomes, radiological improvements in alignment and fusion rates.

Cleaning Efficacy of Poly-ether-ether-ketone Tips in Eliminating Cement Remnants Around Implants With Different Abutment Heights.

The excess cement not removed after the cementation of fixed implant-supported restorations may cause loss of peri-implant attachment or adjacent bone. The aims of this study were to evaluate the amount of residual cement at different abutment-crown connection levels and to test the cleaning efficacy of poly-ether-ether-ketone (PEEK) ultrasonic tips after cementation. One implant was placed in an anterior central tooth position 5 mm below the gingival margin in an acrylic model, and 32 stone models were obtained with implant analogs. Abutment heights of 1-2 and 2.5-4 mm were used on the vestibular and lingual sides, respectively. Crowns were cemented and cleaned, and half of the samples were cleaned again using PEEK tips. The abutment-crown suprastructure was then disconnected, and cleaning efficacy was evaluated. Varying amounts of excess cement were found on all specimens except for the PEEK group with abutment-crown connections 1 mm below the gingival margin. An increase of undetected cement remnants was observed when the restoration margins were located deeper subgingivally. Various amounts of excess cement associated with margin location were detected on the abutment-restoration complex despite meticulous cleaning efforts. Ultrasonic PEEK tips were effective at cleaning the cement remnants around implants to a certain depth.

Effect of Various pH Media on Fracture Toughness and Hardness of Bilayered Reinforced Polymer and Monolithic Hybrid Ceramic

Objective: This study evaluated the effect of various pH media on fracture toughness and hardness of bi layered reinforced polymer and monolithic hybrid ceramic. Materials and Methods: Total of 80 samples were used in this study. Samples were divided into two main groups , Poly Ether Ether Ketone (PEEK) group and Vita Enamic group. Each PEEK and Vita Enamic group were subdivided into 4 subgroups according to PH media used, control group, strong acid media (Pepsi),weak acid media(coffee),distilled water. Testing was performed before and after 24 days of pH media storage. Data was statistically analyzed using Student t-test ,paired t-test and the significance level was set at p ≤ 0.05 . Results: Hardness results with irrespective of material type, was found that baseline subgroup recorded statistically significant highest hardness followed by pH 5.5 subgroup then pH 7 subgroup while pH 2.5 subgroup recorded statistically significant lowest hardness. Fracture toughness results with irrespective of material type, was found that baseline subgroup recorded statistically significant highest fracture toughness followed by pH 7 subgroup then pH 2.5. subgroup while pH 5.5 subgroup recorded statistically significant lowest fracture toughness Conclusion: PEEK material recorded higher fracture toughness mean value than Vita enamic while Vita Enamic material recorded higher hardness mean value than PEEK . Both material affected more by pH2.5(Pepsi)sub group followed by pH 5.5 (coffee) subgroup then pH7 subgroup when measuring hardness. Both material affected more by pH5.5(coffee) subgroup followed by pH2.5 (Pepsi) subgroup then by pH 7 subgroup when measuring fracture toughness.

Polyetheretherketone Versus Titanium Cages for Posterior Lumbar Interbody Fusion: Meta-Analysis and Review of the Literature.

ObjectiveLumbar fusion with implantation of interbody cage is a common procedure for treatment of lumbar degenerative disease. This study aims to compare the fusion and subsidence rates of titanium (Ti) versus polyetheretherketone (PEEK) interbody cages after posterior lumbar interbody fusion and investigate the effect of clinical and radiological outcomes following fusion on patient-reported outcomes. MethodsA systematic search strategy of 4 electronic databases (MEDLINE, Embase, Web of Science, and Cochrane) was conducted using different MeSH (medical subject headings) terms until January 2020. Pooled odds ratios (ORs) with 95% confidence intervals (CI) were calculated using fixed and random-effect models based upon the heterogeneity (I2) to estimate the association between interbody cages and the measured outcomes. ResultsA total of 1,094 patients from 11 studies were reviewed. The final analysis included 421 patients (38.5%) who had lumbar surgery using a Ti and/or a Ti-coated interbody cage and 673 patient (61.5%) who had lumbar surgery using a PEEK cage. Overall, PEEK interbody devices were associated with a significantly lower fusion rate compared with Ti interbody devices (OR, 0.62; 95% CI, 0.41–0.93; p = 0.02). There was no difference in subsidence rates between Ti and PEEK groups (OR, 0.91; 95% CI, 0.54–1.52; p = 0.71). Also, there were no statistically significant differences in visual analogue scale (VAS)-low back pain (p = 0.14) and Japanese Orthopedic Association scale (p = 0.86) between the 2 groups. However, the PEEK group had lower odds of leg pain after surgery compared to the Ti group (OR [VAS-leg], 0.61; 95% CI, 0.28–0.94; p = 0.003). ConclusionTi and Ti-coated PEEK cages used for posterior lumbar interbody fusion are associated with similar rates of subsidence, but a higher rate of fusion compared to PEEK interbody cages. Randomized controlled trials are needed to better assess the effect of cage materials and potential factors that could influence the outcomes of interbody lumbar fusion.

A partial hemi-resurfacing preliminary study of a novel magnetic resonance imaging compatible polyetheretherketone mini-prosthesis for focal osteochondral defects.

BackgroundThe use of partial articular resurfacing surgery with a mini-implant has been gradually increasing; the implant is mainly made of cobalt–chromium metal material, and cartilage changes cannot be monitored after implantation. Thus, we aimed to develop a novel local articular resurfacing polyetheretherketone (PEEK) mini-implant and investigate its feasibility for postoperative magnetic resonance imaging (MRI) monitoring of implant location, bone changes, and cartilage degeneration without artefacts.MethodsNine skeletally mature female standardised goats were used and divided into the sham, PEEK, and cobalt–chromium–molybdenum alloy (Co–Cr–Mo) groups. The animals underwent local articular resurfacing operation with Co–Cr–Mo alloy (Co–Cr–Mo group) and PEEK (PEEK group) mini-implants. X-ray, computed tomography, and MRI examinations were performed at 12 weeks postoperatively. The sham group underwent a similar surgical procedure to expose the femoral head but without implantation. Gross necropsy and surface topography measurement of the articular cartilage of the acetabulum were performed after sacrificing the animals. Imaging artefacts and opposing cartilage degeneration in the acetabulum were also examined.ResultsCartilage damage occurred in both the Co–Cr–Mo and PEEK groups, and the damaged cartilage area was markedly larger in the Co–Cr–Mo group than in the PEEK group, as assessed by gross necropsy and histological staining. The mean surface roughness of the opposing cartilage was approximately 65.3, 117.4, and 188.4 ​μm ​at 12 weeks in the sham, PEEK, and Co–Cr–Mo groups, respectively. The Co–Cr–Mo mini-implant was visualised on radiographs, but computed tomography and MR images were markedly affected by artefacts, whereas the opposing cartilage and surrounding tissue were clear on MR images in the PEEK group. Opposing cartilage damage and subchondral bone marrow oedema could be detected by MRI in the PEEK group.ConclusionsThe PEEK mini-implant can be a novel alternative to the Co–Cr–Mo mini-implant in articular resurfacing to treat focal osteochondral defects with less cartilage damage. It is feasible to postoperatively monitor the PEEK implant location, surrounding bone changes, and opposing cartilage degeneration by MRI without artefacts.The translational potential of this articleThe use of MRI to monitor changes in the opposing cartilage after prosthesis implantation has not been widely applied because MR images are generally affected by artefacts generated by the metal prosthesis. This study revealed that the PEEK mini-implant can be a novel alternative to the Co–Cr–Mo mini-implant in articular resurfacing to treat focal osteochondral defects, and it is feasible to monitor the PEEK implant location, surrounding bone changes, and opposing cartilage damage/degeneration by MRI without artefacts postoperatively.

Porous titanium cervical interbody fusion device in the treatment of degenerative cervical radiculopathy; 1-year results of a prospective controlled trial

Background contextAnterior cervical discectomy with an interbody cage (ACDF) to obtain fusion is a common procedure in cervical spine surgery. Presently, polyetheretherketone (PEEK) with (auto) graft is frequently used for interbody fusion although alternative implant technology like 3-D printing titanium has been introduced recently. PurposeReporting the clinical and quantitative radiological outcome of a prospective cohort of 3-D printed porous titanium implants. Study design/settingProspective study of patients with single level ACDF using 3-D printed porous titanium cervical implants. These data were compared with 48 patients from the PEEK with autograft group of the previously performed CAncellous Structured Ceramic Arthrodesis DEvice trial. Patient sampleFourty-nine patients were included. Outcome measuresNeck disability index (NDI), visual analog scale (VAS), self-reported perceived recovery, and fusion status. MethodsThe clinical outcomes and fusion rates were documented at 3, 6, and 12 months. Dynamic X-rays were analyzed to determine range of motion (ROM) of the operated level. Fusion was defined as rotation ≤4° and ≤1.25 mm translation on flexion-extension films. ResultsThe mean NDI improved from 41.2 preoperatively to 19.4 at 12 months postoperatively. Both VAS arm and VAS neck improved significantly after surgery and 77.1% of the patients reported complete or nearly complete recovery at 12 months. The mean ROM of the affected disc level decreased from 8.7° (range 2.6–21.4) before surgery to 1.6° (0.0–4.6°) after 12 months. The fusion rate at 3, 6, and 12 months was 84%, 89%, and 91% respectively, compared with 67%, 72%, and 90%, in the PEEK group. Conclusions3-D printed porous titanium cervical implants resulted in significant clinical improvement after surgery. The fusion rate of porous titanium compared with PEEK with autograft at 12 months was similar, although porous titanium resulted in faster consolidation. In addition, one level anterior cervical fusion can be successfully achieved without additional plating.

Efficacy Analysis of Percutaneous Endoscopic Lumbar Discectomy Combined with PEEK Rods for Giant Lumbar Disc Herniation: A Randomized Controlled Study.

Objective This study describes a randomized controlled trial that assesses percutaneous endoscopic lumbar discectomy (PELD) combined with a polyetheretherketone (PEEK) rod in patients with GLDH (herniation affecting 50% of the sagittal diameter of the spinal canal) and reports the 2-year follow-up outcome. Methods In all, 243 patients were randomly assigned to undergo PELD or PELD combined with a PEEK rod by generating random numbers with a random number generator. Clinical outcome data, including the numerical rating scale (NRS), were used to assess the patients' back and leg pain, while the Oswestry Disability Index (ODI) was used to quantify pain and disability. Imaging data included intervertebral disc height (IDH), range of motion (ROM), and modified Pfirrmann grades. Results At the final follow-up, the NRS for back and leg pain and the ODI scores were significantly decreased in both groups. The NRS for back pain and the ODI scores in the PELD + PEEK group (1.32 ± 0.70, 14.10 ± 4.74) were better than those in the PELD group (1.91 ± 0.69, 16.93 ± 4.33) (P < 0.05). The IDH of the PELD + PEEK group (10.54 ± 1.62) was significantly higher than that in the PELD group (9.98 ± 1.90) (P < 0.05). The IDH of the PELD + PEEK group (10.54 ± 1.62) was significantly higher than that in the PELD group (9.98 ± 1.90) (P < 0.05). The IDH of the PELD + PEEK group (10.54 ± 1.62) was significantly higher than that in the PELD group (9.98 ± 1.90) (Conclusion For symptomatic patients with GLDH, both PELD and PELD combined with a PEEK rod showed good efficacy. However, the long-term effect of PELD combined with a PEEK rod is better than that of PELD alone. Moreover, PELD combined with a PEEK rod can effectively reduce the recurrence rate. Maximum benefit can be gained if we adhere to strict selection criteria for PELD combined with a PEEK rod.

The Titanium-coated PEEK Cage Maintains Better Bone Fusion With the Endplate Than the PEEK Cage 6 Months After PLIF Surgery: A Multicenter, Prospective, Randomized Study.

A multicenter, randomized, open-label, parallel-group trial. To investigate interbody bone fusion rates in titanium-coated polyetheretherketone (TiPEEK) and polyetheretherketone (PEEK) cages after posterior lumbar interbody fusion (PLIF) surgery. Previous clinical studies have not revealed any significant difference in bone fusion rates between TiPEEK and PEEK cages. During one-level PLIF surgery, 149 patients (84 men, 65 women, mean age 67 yr) were randomly allocated to use either a TiPEEK cage (n = 69) or PEEK cage (n = 80). Blinded radiographic evaluations were performed using computed tomography and assessed by modified intention-to-treat analysis in 149 cases and per-protocol analysis in 143 cases who were followed for 12 months. Clinical outcomes were assessed using the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire and the Oswestry Disability Index. The interbody union rate at 12 months after surgery was 45% owing to a very strict definition of bone fusion. The rates of bone fusion were significantly higher at 4 and 6 months after surgery in the TiPEEK group than in the PEEK group in the unadjusted modified intention-to-treat analysis and were significantly higher at 6 months in the unadjusted per-protocol analysis. Binary logistic regression analysis adjusted for sex, age, body mass index, bone mineral density, and surgical level showed that using a TiPEEK cage (odds ratio, 2.27; 95% confidence interval: 1.09-4.74; P = 0.03) was independently associated with bone fusion at 6 months after surgery. Japanese Orthopaedic Association Back Pain Evaluation Questionnaire and Oswestry Disability Index results improved postoperatively in both groups. Using the TiPEEK cage for PLIF enabled the maintenance of better bone fusion to the endplate than using the PEEK cage at 6 months after the surgery. Our findings suggest the possibility of an earlier return to rigorous work or sports by the use of TiPEEK cage. 1.

In vitro study of surface alterations to polyetheretherketone and titanium and their effect upon human gingival fibroblasts

Statement of problemSoft-tissue attachment to different surfaces may play a pivotal role in the long-term success of dental implants. However, studies on the issue, especially on newer materials, are sparse. PurposeThe purpose of this in vitro study was to evaluate the viability and adhesion of human gingival fibroblasts (HGFs) on different implant abutment materials with specific surface modifications. Material and methodsOne hundred and fifty specimens in 6 experimental groups were evaluated: smooth-machined titanium alloy (Ti), laser-modified titanium (TiL), smooth-machined polyetheretherketone (PEEK) (P), laser-modified PEEK (PL), plasma-treated PEEK (PP), laser- and plasma-treated PEEK (PLP). Machined Ti was considered as the control group. Surface roughness (Sa), water contact angle (WCA), and X-ray photoelectron spectroscopy (XPS) were measured. HGF attachment and proliferation were observed at 1, 3, and 7 days after cell seeding. Comparison of the means among the groups was performed with 1-way analysis of variance (ANOVA) with post hoc comparison using the Tukey test (α=.05). ResultsSa values of the laser modified groups were significantly higher than those of the nonmodified (smooth-machined) groups (P<.001). WCAs were significantly different among PEEK groups, and plasma-sprayed groups had the lowest WCAs. XPS analysis of both Ti and PEEK groups showed laser treatment did not have any significant effect on the surface composition of the PEEK as the same bonds with similar ratio/fraction were detected in the spectrum of the modified specimens. Scanning electron microscopy (SEM) revealed more functionally oriented HGF cells on the laser-grooved surfaces. On the first, third, and seventh day of proliferation, the titanium groups showed no significant differences (P>.05). On the first and third days of proliferation, the plasma sprayed groups (PP, PLP) showed significantly greater proliferation than all experimental groups (P<.001). On the seventh day of proliferation, statistically significant differences were observed between all PEEK groups and between all PEEK groups and the Ti group (P<.001), with the exception of the PL and P groups and the PLP and Ti groups (P>.05). ConclusionsLaser-modified titanium and PEEK surfaces led to guided gingival fibroblast attachment. Plasma treatment of PEEK surfaces increased the wettability of this polymer and improved proliferation of HGF.

Comparison of the Bond Strength of Composite Resin to Zirconia and Composite Resin to Polyether Ether Ketone: An In Vitro Study.

ABSTRACTAim:The aim of the study was to compare the shear bond strength of composite resin bonded to polyether ether ketone (PEEK) and zirconia, and also to evaluate the effect of thermocycling on the shear bond strength.Materials and Methods:A total of 22 zirconia (Group 1) and 22 PEEK (Group 2) specimens (disks of 10 mm in diameter and 10 mm in thickness) were machine milled using computer-aided design (CAD)/computer-aided manufacturing (CAM) from commercially available zirconia and PEEK. These specimens were air abraded with 110-μm aluminum oxide. Following which these two groups were subdivided into four groups, that is, Group 1A: 11 zirconia specimens before thermocycling, Group 1B: 11 zirconia specimens after thermocycling, Group 2A: 11 PEEK specimens before thermocycling, and Group 2B: 11 PEEK specimens after thermocycling. These four groups of specimens were embedded in an acrylic block, and bonding agent was applied over the upper surfaces of the disks of each of these specimens. Composite resin was then cured, and then Group 1B and group 2B were thermocycled under a standard temperature. The bond strength of the specimen was tested using universal testing machine.Result:The result showed that there was no significant difference in shear bond strength between the groups, although higher shear bond strength was observed in the PEEK group.Conclusion:Shear bond strength of PEEK is similar to zirconia. The results suggest that the pretreatment method and primers used were effective in improving the bonding of resin cements to zirconia ceramic and the bonding properties of the veneering resin to the PEEK surface.

Retention force of overdenture retained with telescopic crowns: A comparison of polyether ether ketone and zirconia ceramic telescopic crowns

Introduction/Objective. Recently, new materials for double crowns have been introduced, such as zirconia and polyether ether ketone (PEEK). However, some characteristics of these materials, such as retentive force and duration of ?settling in phase,? have not been investigated sufficiently. During the ?settling in phase,? telescopic overdenture has not yet achieved its definitive retention force, and it can be harmful for periodontal tissue if the value is above optimal for a long period of time. The objective was to measure the in vitro overall pull-off force of telescopic crowns where primary crowns were made from zirconia ceramics and a survey of the ?settling in phase? duration. Methods. Forty zirconia primary telescopic crowns were produced on prepared canine teeth. Twenty secondary crowns were of PEEK and other 20 of zirconia with electroplated gold copings. The pull-off force measurements were conducted utilizing a dynamometer until a constant value was obtained. Results. The specimens of the PEEK group showed higher initial retentive force values. Settling in phase was finished between 800 and 900 cycles of separation for both groups. Comparing the value of the pull-off force between individual different cycles, a statistically significant reduction was recorded up to the 800th cycle, while between the 800th and the 900th cycle there was no difference. Conclusions. The settling in phase was finished between 800 and 900 cycles of separation in both groups. Final retentive force values for both tested telescopic groups were in the optimal range which is 5?9 N per one telescopic crown.

251. Additive manufactured Ti-6Al-4V/polyetheretherketone composite porous cage for interbody fusion: bone growth and biocompatibility evaluation in a porcine model

BACKGROUND CONTEXT Several materials have been used to manufacture the cages, the most common being polyetheretherketone (PEEK) and titanium (Ti) alloy (Ti–6Al–4V). Each material has its advantages and disadvantages. PURPOSE The purpose is to utilize the advantages of each material in combination with additive manufacturing technology to develop a new porous Ti alloy/PEEK composite interbody cage. STUDY DESIGN/SETTING In vitro mechanical tests and cell biocompatibility study; in vivo posterior instrumented interbody fusion porcine model. PATIENT SAMPLE In vitro cell culture analysis for Porous Ti alloy/PEEK composite cages. In vivo animal study used 20 female pigs through an anterior intervertebral lumbar fusion and posterior pedicle screws augmentation. Each level was randomly implanted with one of five testing cages. OUTCOME MEASURES In vitro mechanical tests for shear strength of the interface layer. In vitro cell culture analysis for alkaline phosphatase (ALP) activity, ALP and osteocalcin mRNA expression for in vitro study. Micro–computed tomography (CT), back-scattered-electrons SEM (BSE-SEM) and histological analyses for in vivo study. METHODS In vitro and in vivo study compared 5 groups of cages. The first was a commercialized pure PEEK cage (group 1). The second was a Ti alloy/PEEK composite cage with nonporous Ti alloy end plates (group 2). The third, fourth, and fifth groups were composite cages with porosity of 40%, 60%, and 80% (groups 3, 4, and 5), respectively. Mechanical tests, alkaline phosphatase activity and mRNA expression, osteocalcin mRNA expression, SEM were performed for in vitro study. Micro–computed tomography (CT), back-scattered-electrons SEM (BSE-SEM) and histological analyses were performed for in vivo study. RESULTS The shear strength reached 33.4 MPa at the Ti alloy/PEEK interface. ALP activity and ALP mRNA expression were positively correlated with the porosity rate and peaked at 60% porosity. Micro-CT and BSE-SEM demonstrated that structures with high porosities, especially 60% and 80%, facilitated more bone formation inside the implant but not outside the implants. Histological analysis also showed that bone formation was better in Ti alloy groups than in the PEEK group. CONCLUSIONS In vitro cell culture showed higher porous structure exhibited superior bone growth. Micro-CT and histological analyses showed improved bone growth in high-porosity composite cage groups. Composite cage implant takes the biological advantages of Ti alloy porous end plates and the mechanical and radiographic advantages of PEEK central core to incorporate as a single implant suitable for intervertebral fusion. FDA DEVICE/DRUG STATUS Unavailable from authors at time of publication.

A Randomized Controlled Trial of PEEK Versus Titanium Interference Screws for Anterior Cruciate Ligament Reconstruction With 2-Year Follow-up

Background: Graft fixation with interference screws for anterior cruciate ligament (ACL) reconstruction is a highly successful technique. Polyether ether ketone (PEEK) is a novel thermoplastic polymer with high biocompatibility and mechanical properties that mimic native bone, and it can be imaged on computed tomography or magnetic resonance imaging (MRI) without signal flare. Purpose: To compare the clinical performance of ACL reconstruction with PEEK and titanium interference screws at 2 years and to evaluate a novel method of measuring tunnel volume. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: A total of 133 patients underwent arthroscopic ACL reconstruction with 4-strand hamstring autografts and were randomized to have titanium or PEEK interference screws for femoral and tibial tunnel fixation. At 2 years, subjective Lysholm and International Knee Documentation Committee scores were assessed and clinical examination performed. At 12 months, MRI was performed to assess graft incorporation and cyst formation, and a novel technique was employed to measure tunnel volumes. Results: There were no significant differences in graft rerupture rate, contralateral ACL rupture rate, subjective outcomes, or objective outcomes. In the titanium and PEEK groups, MRI demonstrated high overall rates of graft integration (96%-100% and 90%-93%, respectively) and ligamentization (89% and 84%) and low rates of synovitis (22% and 10%) and cyst formation (0%-18% and 13%-15%). There was a higher proportion of patients with incomplete graft integration within the femoral tunnel in the PEEK group as compared with the titanium group (10% vs 0%, P = .03); however, the authors suggest that metal artifact precluded proper assessment of the graft in the titanium group by MRI. Tunnel volumes also appeared to be equivalent in the 2 groups and were measured with a novel technique that was highly reproducible in the PEEK group secondary to the absence of flare. Conclusion: Two-year clinical analysis of PEEK interference screws for femoral and tibial fixation of ACL reconstructions showed equivalent clinical performance to titanium interference screws. Given the excellent mechanical characteristics, biological compatibility, and absence of metal artifact on MRI, PEEK has become our material of choice for interference screw fixation in ACL reconstruction.

Application of New Allogeneic Lumbar Fusion Cage (Biocage) in Single-Segment Lumbar Degenerative Disease: A Prospective Controlled Study with Follow-Up for ≥2 Years

We evaluated the clinical efficacy of the Biocage in lumbar fusion surgery and its safety and effectiveness. A total of 431 patients with single-segment lumbar degenerative disease diagnosed from January 2013 to December 2016 were considered for the present prospective, nonrandomized, and controlled study; 52 patient met the exclusion criteria and were excluded. The patients were divided into 2 groups according to their cage choice: Biocage (n= 206) and polyether ether ketone (PEEK) cage (n= 173). The patients were followed up for 24-48 months (average, 32). The operative time, blood loss, hospitalization duration, mean intervertebral fusion segment height, height of intervertebral foramen, fusion time, fusion rate, internal fixation failure rate, visual analog scale score, and Oswestry disability index were compared between the 2 groups. All the patients underwent surgery successfully. No significant differences were found in gender, age, clinical diagnosis, lesion segment, operative time, blood loss, visual analog scale score, or Oswestry disability index between the 2 groups. No significant differences were found in the fusion rate; however, the Biocage group had a greater fusion rate and shorter fusion time than the PEEK group. During follow-up, the mean intervertebral height recovered significantly in the Biocage group compared with the PPEK group (P < 0.05). The height of the intervertebral foramen was significantly different between the 2 groups, and recovery was better in the Biocage group (P<0.05). The Cobb angle of fusion segment in both groups improved significantly postoperatively compared with preoperatively (P < 0.05). The improvement in Cobb angle was significantly different between the 2 groups (P < 0.05). The Biocage has excellent clinical efficacy in the treatment of lumbar degenerative disease. Although the Biocage achieved good therapeutic effects, it did not show obvious advantages compared with the PEEK cage. Therefore, the Biocage can only be used as a choice of bone graft materials for lumbar fusion surgery and should not completely replace the PEEK cage.

Fivefold higher rate of pseudarthrosis with polyetheretherketone interbody device than with structural allograft used for 1-level anterior cervical discectomy and fusion.

In BriefThe authors examined fusion rates after single-level anterior cervical discectomy and fusion, comparing use of a structural allograft with use of polyetheretherketone (PEEK) interbody devices packed with bone graft. The results demonstrate superior results of structural allograft in terms of arthrodesis rates and reoperation rates. Currently, reimbursement rates substantially favor the use of PEEK and other synthetic devices, which the authors believe should be changed based on the results of this study.

Evaluation of two-body wear rate and roughness of polyetheretherketone and zirconia opposing enamel structure: an in-vitro study

Background/aim Investigation of polyetheretherketone (PEEK), a new synthetic thermoplastic polymer, as an alternative for zirconia for veneering frameworks, to be used with weakened abutment teeth, as in cases of patients with parafunctional habits. This study aimed to investigate the two-body wear rate and roughness of PEEK and zirconia by itself and against human enamel. Materials and methods A total of six disc-shaped zirconia (n=6) and six disc-shaped PEEK specimens (n=6) (10 mm in diameter with a thickness of 2 mm) were prepared. Human enamel antagonists were produced by sectioning of 12 premolars. The two-body wear testing was performed using chewing simulator. Weight loss was assessed by electronic analytical balance. The optical profilometry was used for roughness evaluation. Results The findings of this study revealed that PEEK showed a comparable effect upon comparison with zirconia, although there was a statistically nonsignificant difference between weight changes recorded for wear in both PEEK and zirconia groups, tested alone or with enamel antagonists, as indicated by the unpaired t test. Moreover, the optical profilometer revealed that, the difference between surface roughness changes recorded for both groups, tested alone or with enamel antagonists, was statistically nonsignificant as indicated by the unpaired t test. Conclusion PEEK showed a promising effect in terms of antagonistic tooth wear and roughness upon comparison with zirconia. However, the results were not significant between both materials.

The n-HA/PA66 Cage Versus the PEEK Cage in Anterior Cervical Fusion with Single-Level Discectomy During 7 Years of Follow-Up

The nano-hydroxyapatite/polyamide66 (n-HA/PA66) cage is a novel biomimetic nonmetal cage, whereas the polyetheretherketone (PEEK) cage has been widely used for decades with excellent clinical outcomes. However, there has been no long-term comparison of these 2 cages in anterior cervical reconstruction. This retrospective study included 98 patients who underwent single-level anterior cervical decompression and fusion (ACDF) from January 2009 to June 2011 with at least 7 years of follow-up; the PEEK cage was used in 51 patients (PEEK group), whereas the n-HA/PA66 cage was used in 47 (n-HA/PA66 group). The groups were compared regarding radiographic (cage subsidence, fusion status, cervical lordosis, and segmental sagittal alignment) and clinical (10-point visual analog scale and Japanese Orthopedic Association scores) parameters preoperatively, postoperatively, and at the final follow-up. The n-HA/PA66 and PEEK cages had similar fusion rates at the final follow-up (97.9% vs. 98.0%). The respective cage subsidence rates in the PEEK and n-HA/PA66 cage groups were 9.8% and 10.6%. There were no significant differences between the 2 groups in mean cervical lordosis, mean interbody height, segmental sagittal alignment, cervical lordosis, and 10-point visual analog scale and Japanese Orthopedic Association scores at the final follow-up. The n-HA/PA66 cages resulted in high fusion and low subsidence rates during long-term follow-up. After single-level ACDF, the n-HA/PA66 cage showed similar radiographic fusion, subsidence rate, and clinical results compared with the PEEK cage during 7years of follow-up. These results suggest that the n-HA/PA66 cage could be comparable with the PEEK cage for ACDF.

Hard and Soft Tissue Cell Behavior on Polyetheretherketone, Zirconia, and Titanium Implant Materials

The aim of this study was to characterize and compare the behavior of human osteoblasts and human gingival fibroblasts in contact with polyetheretherketone (PEEK), zirconia, and titanium implant surface materials. PEEK, yttria-stabilized zirconia (YTZP), and titanium discs were produced under appropriate and similar conditions to achieve controlled surface features. Human osteoblasts and human gingival fibroblasts were cultured on discs for 14 days. Cell viability and proliferation were evaluated using a resazurin-based method. Morphology and cellular adhesion were observed using field emission gun-scanning electron microscopy (FEG-SEM). Alkaline phosphatase (ALP) activity and bone cell mineralization were evaluated on osteoblasts. Confocal laser scanning microscopy (CLSM) images of fluorescent-stained fibroblasts were obtained at 7 and 14 days of the culture. Results were presented as mean and standard deviation (SD). Group comparisons were tested using analysis of variance (ANOVA) (Tukey's post hoc) with appropriate statistical software, and significance was set at P < .05. Cell viability and proliferation were higher in PEEK and YTZP groups compared with titanium on osteoblast cells (P < .05, all time points) and on fibroblasts (P < .05, 7 and 14 days). All groups showed an increase in ALP activity over time, which was not significant. Mineralization patterns demonstrated an increase in mineral content over time, which was more apparent in the YTZP group. Cell spreading was more evident on PEEK and YTZP specimens. The results suggest increased adhesion, viability, and proliferation of osteoblasts and gingival fibroblasts on zirconia and PEEK surfaces compared with titanium. These results are correlated with the increased wettability of these materials.

Porous PEEK improves the bone-implant interface compared to plasma-sprayed titanium coating on PEEK

Polyether-ether-ketone (PEEK) is one of the most common materials used for load-bearing orthopaedic devices due to its radiolucency and favorable mechanical properties. However, current smooth-surfaced PEEK implants can lead to fibrous encapsulation and poor osseointegration. This study compared the in vitro and in vivo bone response to two smooth PEEK alternatives: porous PEEK and plasma-sprayed titanium coatings on PEEK. MC3T3 cells were grown on smooth PEEK, porous PEEK, and Ti-coated PEEK for 14 days and assayed for calcium content, osteocalcin, VEGF and ALP activity. Osseointegration was investigated by implanting cylindrical implants into the proximal tibiae of male Sprague Dawley rats for 8 weeks. Bone-implant interfaces were evaluated using μCT, histology and pullout testing. Cells on porous PEEK surfaces produced more calcium, osteocalcin, and VEGF than smooth PEEK and Ti-coated PEEK groups. Bone ingrowth into porous PEEK surfaces was comparable to previously reported porous materials and correlated well between μCT and histology analysis. Porous PEEK implants exhibited greater pullout force, stiffness and energy-to-failure compared to smooth PEEK and Ti-coated PEEK, despite Ti-coated PEEK exhibiting a high degree of bone-implant contact. These results are attributed to increased mechanical interlocking of bone with the porous PEEK implant surface. Overall, porous PEEK was associated with improved osteogenic differentiation in vitro and greater implant fixation in vivo compared to smooth PEEK and Ti-coated PEEK. These results suggest that not all PEEK implants inherently generate a fibrous response and that topography has a central role in determining implant osseointegration.