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STATEMENT OF PROBLEM: The mechanical properties of polyetheretherketone (PEEK) make it an ideal material for fixed dental prostheses; however, insufficient information is available about the cementation of these restorations. PURPOSE: The purpose of this study was to evaluate the retention strength of differently pretreated and conditioned PEEK crowns luted to dental abutments. MATERIAL AND METHODS: Human teeth were prepared in a standardized manner, and PEEK crowns were milled (N=160, n=10 per group) and conditioned as follows: airborne-particle abrasion, sulfuric etching, piranha etching, and no conditioning. These groups were divided into adhesive systems: visio.link, Signum PEEK Bond, Ambarino P60, and no adhesive and luted to dentin abutments. After water storage (60 days) and thermocycling (5000 cycles, 5°C/55°C), the retention strength of the crowns was determined with a pull-off test, and failure types were classified. The data were analyzed with the Kruskal-Wallis, 1-way ANOVA, and (2) test (=.05). RESULTS: Crowns that were unconditioned and piranha etched and/or adhesively untreated or pretreated with Ambarino P60 had the lowest retention strength. The highest values were found for the airborne-particle abrasion and sulfuric etched groups and/or crowns adhesively pretreated with Signum PEEK Bond and visio.link. Composite resin cement that remained on dentin was observed more frequently for unconditioned groups in combination with Ambarino P60 and no adhesive pretreatment. Mixed failure types were found more frequently in the airborne-particle abrasion group in combination with visio.link, Signum PEEK Bond, and no adhesive pretreatment, in the sulfuric acid etched group combined with Ambarino P60 and no adhesive pretreatment, and after the piranha acid pretreatment in combination with visio.link or Signum PEEK Bond. CONCLUSIONS: The adhesion of the tested PEEK crowns to dentin was satisfactory after treatment with airborne-particle abrasion or etching with sulfuric acid and/or when additional adhesive systems such as visio.link or Signum PEEK Bond were used. The effect of surface modification on the retention strength of PEEK crowns adhesively bonded to dentin abutments Statement of problem. The mechanical properties of polyetheretherketone (PEEK) make it an ideal material for fixed dental prostheses (FDPs); however, insufficient information is available about the cementation of these restorations.Purpose. The purpose of this study was to evaluate the retention strength of differently pretreated and conditioned PEEK crowns luted to dental abutments. Material and methods.Human teeth were prepared in a standardized manner and PEEK crowns were milled (N=160, n=10 per group) and conditioned as follows: airborne-particle abrasion, sulfuric etching, piranha etching, and no conditioning. These were divided into adhesive systems: visio.link, Signum PEEK Bond, Ambarino P60, and no adhesive and luted to dentin abutments. After water storage (60 days) and thermocycling (5000 cycles, 5°C/55°C), the retent...

2014). Work of adhesion between resin composite cements and PEEK as a function of etching duration with sulfuric acid and its correlation with bond strength values. AbstractObjective. This study investigated the impact of sulfuric acid etching duration of PEEK on work of adhesion (WA) with resin composite cements, and compared additionally measured surface parameters to shear bond strength (SBS) results.Methods. PEEK specimens were fabricated and divided according to different etching times using 98% sulfuric acid (N=448/n=54): 0,5,15, 30, 60, 90, 120 or 300s, respectively. The resin composite cements RelyX ARC, Variolink II and Clearfil SA Cement (N=54/n=18) were smoothed on a glass plate. The sessile drop method was applied in all contact-angle measurements; distilled water and diiodomethane served as testing liquids. Overall 1,350 single contact angle measurements were performed. Thereafter, surface free energy (SFE), WA, interfacial tension (IFT) and spreading coefficient (SC) of all combinations between etched PEEK and resin composite cements were calculated. Data were statistically analysed using Kolmogorov-Smirnov, Shapiro-Wilk tests, descriptive statistics and two-/one-way ANOVA with post-hoc Scheffé test (p<0.05). Using Pearson correlation the association between SFE values and SBS results of a previous study was investigated.Results. Variolink II showed the lowest WA, followed by RelyX ARC and Clearfil SA Cement, respectively. Etching specimens for 60 s showed the lowest WA values while etching times between 0 s and 30 s, and 300 s showed higher results. WA values for groups etched for 90 s and 120s showed no differences when compared to the 60s groups. SFE and disperse percentage showed a positive correlation with SBS. A negative correlation was observed between SBS and polar percentage for etched PEEK, WA, IFT and SC. Conclusions.The WA values do not allow statements about the bond between two materials to be made; other parameters must be taken into account. A waiver of conventional bond test methods is not possible. Figure 1: Different drop topographies of water (left) and diiodomethane (right).

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This study investigated the influence of different surface treatments on fracture load (FL) of canine crowns fabricated from two different pressable lithium-disilicate ceramics: A (HS10PC, estetic ceram, n=180) and B (IPS e.max Press, IvoclarVivadent, n=120). The standardized specimens were divided into groups of six different surface treatments and two glazing temperatures. A-group specimens were additionally assigned two glazing pastes with various thermal expansion coefficients (TEC). FL was measured and TECs were determined. Data were analyzed using three/one-way ANOVA followed by post-hoc Scheffe's test. B showed comparable or higher FL than A (B: 503-876 N; A: 375-734 N). Lithium-disilicate crowns show higher FL when not grinded but only polished or glazed. Glazing pastes affected FL depending on their TECs, firing temperature and crown treatment. TEC of A and B was 10 ppm/K, glazing pastes for A presented TECs of 7.5 ppm/K and 10 ppm/K and for B of 9 ppm/K.