Double-Crown Prosthesis Retention Using Polyetherketoneketone (PEKK): An In Vitro Study

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Prosthodontics

Background:

• Telescopic crowns are crucial for retaining prostheses.
• Assessing the long-term stability of novel materials like polyetherketoneketone (PEKK) is essential for clinical application.
• Conventional materials like gold alloys are well-established but can be expensive.

Purpose of the Study:

• To evaluate the retentive force of telescopic crowns fabricated with polyetherketoneketone (PEKK) compared to conventional materials over extended in vitro testing.
• To investigate the durability and wear characteristics of PEKK in double crown systems.

Main Methods:

• Thirty-six double crown sets were fabricated using PEKK combined with zirconia, titanium, cobalt-chrome, or PEKK itself, alongside a gold/galvano-gold control.
• A 20,000-cycle insertion-removal test was conducted to simulate long-term use.
• Retentive forces were measured, and surface conditions were analyzed using two-way ANOVA.

Main Results:

• Retentive forces significantly decreased over time for zirconia/PEKK and titanium/PEKK groups.
• PEKK/PEKK, gold/PEKK, and the gold/galvano-gold control groups showed significant increases or stable retentive forces.
• Similar surface wear patterns were observed on the primary crowns of PEKK/PEKK, gold/PEKK, and control groups.

Conclusions:

• PEKK/PEKK and gold/PEKK telescopic crowns exhibited retentive force transitions comparable to the gold control.
• PEKK demonstrated comparable surface wear to conventional gold, indicating good durability.
• PEKK presents a promising high-performance polymer with potential for clinical use in telescopic crown fabrication.