Osseointegration of surface-modified polyetheretherketone (PEEK) implants was studied in vivo. A total of 18 cylinder-shaped PEEK implants were inserted in the femurs of nine New Zealand rabbits; half were coated with nanocrystalline hydroxyapatite (nanoHA) and half were uncoated controls. Healing time was 6 weeks. Samples were retrieved with the implant and surrounding tissue, processed to cut and ground sections, and analyzed histomorphometrically. The implant surfaces were analyzed with optical interferometry, scanning electron microscopy (SEM), atomic force microscopy, and X-ray photoelectron spectroscopy (XPS). NanoHA-coated PEEK surfaces had lower height deviation (Sa) than controls [mean ± SD: 0.41 μm (± 0.14) vs. 0.96 μm (± 0.28)]. SEM images showed the nanoHA crystals as a thin layer on the polymer surface. XPS analysis of the coated implants showed a Ca/P ratio of 1.67. Histomorphometry indicated that the nanoHA-coated implants had more bone-to-implant contact [16% (± 4.7) vs. 13% (± 9.3)] and more bone area [52% (± 9.5) vs. 45% (± 11.9)]. We found no difference between smooth nanoHA-coated cylinder-shaped PEEK implants and uncoated controls. However, higher mean bone-to-implant contact indicated better osseointegration in the coated implants than in the uncoated controls. The large number of lost implants was interpreted as a lack of primary stability due to implant design.

Background: Various designs of dental implants representing different geometries and surface technologies are commercially available and clinically used in patients. However, data with regard to bone tissue responses and stability for comparison of their biologic performances are rare. Purpose: The aim of the present experimental investigation was to compare the bone tissue responses and implant stability between two commonly used dental implants representing different geometries and surface characteristics. Materials and Methods: A total of 90 dental implants (4.3 mm in diameter, 10 mm long) with an oxidized surface (Replace Select Tapered, TiUnite, Nobel Biocare AB, Gothenburg, Sweden) (OX) and 90 implants (4.1 mm in diameter, 10 mm total length) with a hydrophilic sand‐blasted and acid etched surface (Standard Plus, SLActive, Institut Straumann AG, Basel, Switzerland) (HSBA) were placed in the distal femur (n = 1) and tibia (n = 2) of 30 rabbits. The implants were analyzed with implant stability quotient (ISQ) measurements, removal torque (RTQ) and histomorphometry (bone–implant contact, BIC) after 10 days, 3, and 6 weeks. Moreover, RTQ values were corrected for differences in surface area by calculating the shear strength for each implant. Results: RTQ and ISQ measurements showed an increase with time for both implant types. A significantly higher RTQ value was observed for the HSBA implant at 3 weeks (p = .05). A lower ISQ value was seen for HSBA than for OX implants at placement in the tibia (p < 0.001). HSBA implants showed higher shear strength values than OX implants after 3 weeks (p < .001), and 6 weeks (p < .01). The morphometric measurements showed significantly higher BIC for HSBA implants after 10 days (p < .01), similar values after 3 weeks and significantly higher BIC for OX implants after 6 weeks (p < .001). Conclusions: Both HSBA and OX implants were well integrated in bone and showed firm and increased stability from placement to after 6 weeks of healing. The HSBA implant showed more BIC after 10 days and the OX implant more BIC after 6 weeks of healing. The HSBA implant showed significantly higher shear strength after 3 and 6 weeks and higher RTQ values after 3 weeks than the OX implant. The results may be due to differences in surface roughness and hydrophilic properties.

Our findings demonstrate that implants with a threaded design render good stability to PEEK in both coated and uncoated implants. Nanohydroxyapatite-coated PEEK implants demonstrated improved bone formation compared with uncoated controls.

Objective Polyetheretherketone (PEEK) is a polymer used in devices in orthopedic and dental rehabilitation. The aim of this in vitro study was to compare biofilm formation by a range of important oral bacterial species on PEEK, blasted PEEK, commercially pure titanium (cp‐Ti), and titanium‐6 aluminium‐4 vanadium (Ti6Al4V). Material and methods Coin‐shaped samples were manufactured, and the surfaces were characterized using optical interferometry, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, and contact angle measurements. Bacterial species of Streptococcus sanguinis, Streptococcus oralis, Enterococcus faecalis , and Streptococcus gordonii were cultured on the four material surfaces for varying amounts of time. Biofilms were quantified following staining with crystal violet. Results Roughness and contact angle results showed blasted PEEK > PEEK > cp‐Ti = Ti6Al4V. There was increased biofilm formation on blasted PEEK by S. sanguinis, S. oralis , and S. gordonii , whereas the bacterial adhesion was similar on PEEK, cp‐Ti, and Ti6Al4V. The bacterial growth of E. faecalis was significantly higher on cp‐Ti compared with the other three groups. Conclusion The results, taking into consideration the biofilm formation, suggest that PEEK should perform as well as cp‐Ti or TiAl6V4 when used as a dental restorative material.

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