Bond strength of recently introduced computer-aided design and computer-aided manufacturing resin-based crown materials to polyetheretherketone and titanium.

Statement Of Problem: Several additively and subtractively manufactured resin-based materials indicated for interim and definitive fixed dental prostheses have been launched. However, knowledge of the bond strength of these materials to different implant abutment materials is limited.

Purpose: The purpose of this in vitro study was to evaluate the shear bond strength (SBS) of additively and subtractively manufactured resin-based materials to different implant abutment materials.

Material And Methods: One hundred and ten disk-shaped specimens (Ø3×3 mm) were fabricated either additively from 2 resins indicated for definitive use (Crowntec; AM_CT and VarseoSmile Crown Plus; AM_VS) and 1 resin indicated for interim use (FREEPRINT temp; AM_FP) or subtractively from a nanographene-reinforced polymethyl methacrylate (G-CAM; SM_GC) and a high-impact polymer composite (breCAM.HIPC; SM_BC). After allocating 2 specimens from each group for scanning electron microscope evaluation, the specimens were divided according to the abutment material (CopraPeek; polyetheretherketone, PEEK and Dentium Superline Pre-Milled Abutment; titanium, Ti) (n=10). All specimens were airborne-particle abraded with 50-µm aluminum oxide. After applying a resin primer (Visio.link) to PEEK and an adhesive primer (Clearfil Ceramic Primer Plus) to Ti specimens, a self-adhesive resin cement (PANAVIA SA Cement Universal) was used for cementation. All specimens were stored in distilled water (24 hours, 37 °C), and a universal testing device was used for the SBS test. SBS data were analyzed with 2-way analysis of variance and Tukey honestly significant difference tests, while the chi-squared test was used to evaluate the difference among the abutment-resin pairs in terms of failure modes (α=.05).

Results: The interaction between the material type and the abutment type and the main factor of material type affected the SBS (P<.001). SM_BC-PEEK and SM_GC had the lowest SBS followed by SM_BC-Ti, whereas AM_VS-PEEK had the highest SBS (P≤.001). AM_CT-Ti had higher SBS than AM_FP-PEEK (P=.026). SM_GC had the lowest and AM_VS had the highest SBS, while AM_CT and AM_FP had higher SBS than SM_BC (P≤.004). The distribution of failure modes was significantly different among tested material-abutment pairs, and only for AM_CT among tested materials (P≤.025). Most of the material-abutment pairs had a minimum of 80% adhesive failures.

Conclusions: Regardless of the abutment material, additively manufactured specimens had higher bond strength and one of the subtractively manufactured materials (SM_GC) mostly had lower bond strength. The abutment material had a small effect on the bond strength. Adhesive failures were observed most frequently.