Effects of Nd: YAG LASER irradiation and O2 plasma on the adhesive performance of poly-ether-ether-ketone (PEEK).

PURPOSE: To evaluate the effects of neodymium-doped yttrium aluminum garnet (Nd: YAG) LASER irradiation and oxygen (O2) plasma on the adhesive performance of polyether ether ketone (PEEK) and resin adhesive. METHODS: Nd: YAG LASERs of varying powers and O2 plasma for different durations were used to modify PEEK. A total of 168 PEEK specimens were randomly divided into seven groups (n = 24/group): (A) Control group: untreated PEEK, (B) L0.75 group: PEEK modified with 0.75 W Nd: YAG LASER, (C) L1 group: PEEK modified with 1.0 W Nd: YAG LASER, (D) L1.25 group: PEEK modified with 1.25 W Nd: YAG LASER, (E) P15 group: PEEK modified with 15 min of O2 plasma, (F) P25 group: PEEK modified with 25 min of O2 plasma, and (G) P35 group: PEEK modified with 35 min of O2 plasma. The surface characteristics of the materials were comprehensively analyzed using a scanning electron microscope (SEM), profilometer, energy-dispersive spectrometer (EDS), and contact angle tester. The adhesive specimens were bonded with Variolink N resin adhesive in all groups and each group was further divided into two subgroups (n = 12/group): (a) water storage for 56 h at 37 °C and (b) thermal cycling 5000 times. Shear bond strength (SBS) was tested using a universal testing machine, and the fracture modes were observed using an automated chemiluminescence analysis system to assess the effects of Nd: YAG LASER and O2 plasma on the bond strength of PEEK to resin adhesive. RESULTS: Both Nd: YAG LASER and O2 plasma treatments altered the surface characteristics of PEEK and significantly increased the SBS between PEEK and Variolink N resin adhesive. The L0.75 group (Nd: YAG LASER) and the P35 group (O2 plasma) achieved the highest SBS, respectively. Furthermore, the SBS of the L0.75 group was higher than that of the P35 group. Following thermal cycling, SBS values decreased compared to the water storage subgroups. The fracture modes of the specimens in each group were predominantly interfacial and mixed, with no cohesive fractures observed. CONCLUSIONS: Nd: YAG LASER irradiation and O2 plasma treatments can improve the SBS between PEEK and resin adhesive, with the 0.75 W Nd: YAG LASER being the preferred treatment method.

The effects of three cold plasma treatments on the osteogenic activity and antibacterial property of PEEK.

OBJECTIVE: This study examines the differences in osteogenic activity and antibacterial property among polyetheretherketone (PEEK) treated by three types of cold plasma. METHODS: Standard PEEK specimens were randomly assigned to four groups, which were named according to the treatment: PEEK-C (untreated), PEEK-A (Ar cold plasma treatment), PEEK-N (N2 cold plasma treatment), and PEEK-AN (90% Ar and 10% N2 mixed cold plasma treatment). Physical and chemical properties of the specimen surfaces were determined by scanning electron microscopy (SEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and drop shape analyzer (DSA). MC3T3 osteoblasts were used in vitro to determine the osteogenic activity by cell adhesion morphology observation, cell counting-kit 8 (CCK-8) assay, and alkaline phosphatase (ALP) activity assay. Streptococcus mutans and Staphylococcus aureus were used in vitro to determine the antibacterial property by a plate colony-counting method and bacterial adhesion morphology observation. RESULTS: SEM and AFM analysis showed that the PEEK-C surface was smooth, whereas matrix-arranged nanoprotrusions appeared on the surface of the experimental groups: scaly nano-protrusions appeared on the PEEK-A and PEEK-AN surfaces, while dendritic nanoprotrusions appeared on the PEEK-N surface. Among the experimental groups, PEEK-AN had the finest surface nanoprotrusions. The roughness of the experimental groups increased compared with the PEEK-C group: the PEEK-N group was the roughest with a Ra of 192.60 ± 5.89 nm and PEEK-A was the smoothest with a Ra of 99.60 ± 5.43 nm. The hydrophilicity of the experimental groups was significantly enhanced compared with the PEEK-C group, among which, PEEK-N was the strongest and PEEK-A the weakest. The osteogenic activity and antibacterial property of the experimental groups displayed a remarkable increase compared with the PEEK-C group. Among the experimental groups, PEEK-N displayed the best osteogenic activity while PEEK-AN possessed the strongest antibacterial property. The osteogenic activity and antibacterial performance of PEEK-A were the weakest. Among these treatments, the N2 cold plasma treatment was the most suitable modification method for PEEK application in dental implant. SIGNIFICANCE: Cold plasma treatment is a promising method to improve PEEK osteogenic activity and antibacterial properties. This study provides a theoretical basis for future research on PEEK cold plasma treatment.

Construction and performance evaluation of a sustained release implant material polyetheretherketone with antibacterial properties.

OBJECTIVE: This study aimed to construct a tightly binding antibiotic sustained release system on the polyetheretherketone (PEEK) surface and investigate the cellular activity and antibacterial properties of the new oral implant materials. METHODS: Low-temperature argon plasma under certain parameters was used to prepare P-PEEK with nano-topology, and chemical deposition technology was adopted to form a polydopamine (PDA) coating on the PEEK surface to build a biological binding platform, PDA/P-PEEK. Subsequently, vancomycin gelatin nanoparticles (Van-GNPs) were prepared by two-step desolvation method. Finally, Van-GNPs were combined with PEEK implant material surface to form a new composite material, Van-GNPs/PEEK. scanning electron microscope (SEM), atomic force microscope (AFM), energy dispersive spectrometer (EDS), and contact angle tester were used to comprehensively characterize the materials. The in vitro release test of Van was performed by dynamic dialysis with ultraviolet spectrophotometer. The cell cytotoxicity and adhesion tests were studied by mouse embryonic osteoblasts. The antibacterial properties were evaluated by bacterial adhesion test, plate colony counting, and antimicrobial ring test with Staphylococcus aureus and Streptococcus mutans. RESULTS: PEEK was treated with low-temperature argon plasma and attached to PDA to form a biological binding platform. The synthesized Van-GNPs were smooth, round, with uniform particle size distribution, and bound to PEEK to form a new composite material, which can release Van constantly. Cell experiments showed that Van-GNPs/PEEK had no cytotoxicity and had good interaction with osteoblasts. Bacterial experiments showed that surface conjugation with Van-GNPs could significantly improve the antibacterial performance of PEEK against S. aureus and S. mutans. SIGNIFICANCE: This study demonstrated that Van-GNPs/PEEK have good cellular compatibility and autonomous antibacterial properties, which provide a theoretical basis for the wide application of PEEK in the field of stomatology.

[Experience introduction of induced eruption on multiple adjacent impacted teeth in anterior maxillary bone].

OBJECTIVE: To study the method of induced eruption on multiple adjacent impacted teeth in anterior maxillary bone. METHODS: Twenty-two multiple adjacent impacted teeth of 9 cases were chosen. The position of the impacted teeth and the relationship to each other were assessed on X-ray images, oral examination and plaster model. The impacted teeth were extracted or induced erupted with the closed-eruption technique and fixed orthodontic appliances. RESULTS: Of 22 impacted teeth, 19 impacted teeth were moved into arches by induced eruption with the closed-eruption technique and fixed orthodontic appliances. There were not root adsorption or conglutination for 19 impacted teeth. Three impacted teeth with deformed root were extracted. The average time for treatment was 19 months. CONCLUSION: With correct diagnosis, reasonable design, the complicated impacted teeth could be moved into alignment with good esthetic and functional effect.