Retention Strength of Zirconia Crowns Cemented onto PEEK Abutments Using Two Different Types of Resin Cement With or Without Primer Application-An In Vitro Study.

PURPOSE: To evaluate the retention of zirconia crowns on polyetheretherketone (PEEK) abutments using different luting agents, with and without PEEK primer. MATERIALS AND METHODS: A total of 100 PEEK abutment replicas were fabricated, airborne particle-abraded with aluminum oxide, and divided into four groups (n = 25). A total of 100 zirconia crowns were fabricated and cemented using either adhesive resin cement or self-adhesive resin cement with and without PEEK primer; thus, the groups were: group AA-P (adhesive cement with primer); group AA-N (adhesive cement without primer); group SA-P (self-adhesive cement with primer); and group SA-N (self-adhesive cement without primer). The specimens were thermocycled and subjected to crown pull-out tests. The values were recorded and analyzed using analysis of variance and post hoc analysis (α = .05). The mode of failure of debonded surfaces was evaluated using scanning electron microscopy. RESULTS: The pull-out force values were 3.13 ± 0.31 MPa for group AA-P, 1.77 ± 0.20 MPa for group AA-N, 2.10 ± 0.12 MPa for group SA-P, and 1.49 ± 0.18 MPa for group SA-N. Statistically significant differences were found between all four groups (P < .001). The specimens with PEEK primer applied showed higher values compared to nonprimed specimens for both cements tested. Scanning electron microscopy analysis showed more mixed failures for adhesive cement and more adhesive failures for self-adhesive resin cement. CONCLUSION: The maximum pull-out forces were recorded for zirconia crowns bonded to PEEK abutments with adhesive cement. The use of PEEK primer increased the pull-out values for both resin cements.

Randomized clinical trial of zirconia and polyetheretherketone implant abutments for single-tooth implant restorations: A 5-year evaluation.

STATEMENT OF PROBLEM: Titanium-supported polyetheretherketone (PEEK) abutments provide an economic alternative to zirconia abutments in esthetically important areas. Research comparing the performance regarding esthetics, longevity, and biologic parameters of PEEK abutments is lacking. PURPOSE: The purpose of this clinical study was to determine whether PEEK implant abutments provide similar esthetic and biologic parameters and survival rates as zirconia implant abutments. MATERIAL AND METHODS: Forty participants (age 20 to 50 years) receiving maxillary anterior and premolar implants were enrolled in the study and randomly assigned into 1 of 2 groups: Group PEEK (20 titanium-supported PEEK abutments) and group ZIR (20 zirconia abutments). Both groups were restored with pressed lithium disilicate ceramic crowns. Technical, biologic, and esthetic evaluation was performed at baseline and at 1, 3, and 5 years. The probing pocket depth, plaque control record, and bleeding on probing were recorded at the abutments (test) and compared with those at the corresponding contralateral teeth (control) and also between the 2 test groups. Standardized digital radiographs of the implants were made, and the bone level was recorded with the implant shoulder as the reference on the mesial and distal sides. The color difference between the peri-implant mucosa and control teeth gingiva and the discoloration of the implant crowns were determined with a spectrophotometer. The Student unpaired t test and repeated-measure ANOVA were used to statistically analyze the data (α=.05). RESULTS: From the 5-year evaluation, both PEEK and zirconia abutments with ceramic crowns showed 100% survival rate without any fracture or restoration loss. Differences in the biologic parameters of zirconia and PEEK abutments were statistically similar: mean probing pocket depth (group ZIR: 2.32 ±0.50 mm, group PEEK: 2.13 ±0.60 mm); mean plaque control record (group ZIR: 0.19 ±0.19, group PEEK: 0.15 ±0.17); and mean bleeding on probing (group ZIR: 0.12 ±0.11, group PEEK: 0.08 ±0.12). The mean marginal bone loss at 5 years was similar for implants supporting zirconia and PEEK abutments: mean mesial bone level (group ZIR: 1.8 ±0.5 mm; group PEEK: 1.9 ±0.6 mm), and mean distal bone level (group ZIR: 1.7 ±0.6 mm, group PEEK: 1.8 ±0.3 mm). The initial color difference (ΔE) between the peri-implant mucosa and gingiva of the analogous contralateral teeth diminished over time. No discoloration of the definitive restoration supported by PEEK or zirconia was detected over 5 years. CONCLUSIONS: At the 5-year evaluation, zirconia and PEEK abutments exhibited the same survival rate with similar biologic and esthetic outcomes.