Fatigue and Fracture Resistance Testing of Polyether Ether Ketone (PEEK) Implant Abutments in an Ex Vivo Chewing Simulator Model

Comparative Analysis of the Mechanical Properties and Biocompatibility between CAD/CAM and Conventional Polymers Applied in Prosthetic Dentistry

Modern media often portray CAD/CAM technology as widely utilized in the fabrication of dental prosthetics. This study presents a comparative analysis of the mechanical properties and biocompatibility of CAD/CAM (Computer-Aided Design/Computer-Aided Manufacturing) polymers and conventional polymers commonly utilized in prosthetic dentistry. With the increasing adoption of CAD/CAM technology in dental laboratories and practices, understanding the differences in material properties is crucial for informed decision-making in prosthodontic treatment planning. Through a narrative review of the literature and empirical data, this study evaluates the mechanical strength, durability, esthetics, and biocompatibility of CAD/CAM polymers in comparison to traditional polymers. Furthermore, it examines the implications of these findings on the clinical outcomes and long-term success of prosthetic restorations. The results provide valuable insights into the advantages and limitations of CAD/CAM polymers, informing clinicians and researchers about their suitability for various dental prosthetic applications. This study underscores the considerable advantages of CAD/CAM polymers over conventional ones in terms of mechanical properties, biocompatibility, and esthetics for prosthetic dentistry. CAD/CAM technology offers improved mechanical strength and durability, potentially enhancing the long-term performance of dental prosthetics, while the biocompatibility of these polymers makes them suitable for a broad patient demographic, reducing the risk of adverse reactions. The practical implications of these findings for dental technicians and dentists are significant, as understanding these material differences enables tailored treatment planning to meet individual patient needs and preferences. Integration of CAD/CAM technology into dental practices can lead to more predictable outcomes and heightened patient satisfaction with prosthetic restorations.

Characterization of the Polyetheretherketone Weldment Fabricated via Rotary Friction Welding

Polyether ether ketone (PEEK) is frequently employed in biomedical engineering due to its biocompatibility. Traditionally, PEEK manufacturing methods involve injection molding, compression molding, additive manufacturing, or incremental sheet forming. Few studies have focused on rotational friction welding (RFW) with PEEK plastics. Based on years of RFW practical experience, the mechanical properties of the weldment are related to the burn-off length. However, few studies have focused on this issue. Therefore, the main objective of this study is to assess the effects of burn-off length on the mechanical properties of the welded parts using PEEK polymer rods. The welding pressure can be determined by the rotational speed according to the proposed prediction equation. The burn-off length of 1.6 mm seems to be an optimal burn-off length for RFW. For the rotational speed of 1000 rpm, the average bending strength of the welded parts was increased from 108 MPa to 160 Mpa, when the burn-off length was increased from 1 mm to 1.6 mm and the cycle time of RFW was reduced from 80 s to 76 s. A saving in the cycle time of RFW of about 5% can be obtained. The bending strength of the welded part using laser welding is lower than that using RFW, because only the peripheral material of the PEEK cylinder was melted by the laser.

Clinical Efficacy Analysis of the Personalization of Prosthetic Abutments in Implant Supported Restorations in Comparison to Available Standard Titanium Abutments

Personalized medicine has become an important direction to offer better solutions for health problems. In implantology, this trend was materialized through customizing dental abutments to each clinical situation. The demands for better esthetics and function of implant-supported restorations have imposed a more personalized variety of prosthetic abutments. This retrospective study compared clinical efficiency of personalized implant abutments with standard implant abutments in multiple implant restorations. Clinical data of patients who were admitted in a private clinic between 2011 and 2022 and received dental implant treatments were collected. All complications and undesired events from the patients' medical record charts were statistically analyzed. The implants were loaded using either standard or customized abutments. For complete arch rehabilitations with the SKY Fast & Fixed protocol, standard titanium prosthetic abutments were used. Our results suggest that the abutments choice for patients has moved throughout the years more towards the use of customized abutments. The number of customized abutments (414) was higher compared with the number of standard abutments (293). In our database, the most used abutments for the anterior area implants were made of titanium and zirconia, whereas for the posterior area, the preferred abutments were mostly titanium. The standard abutments were used almost entirely for immediate loading and implantation in both anterior and posterior areas (Fast & Fixed protocol). Complications were encountered mainly in restorations with standard abutments (9.22%) compared to customized abutments (2.7%), with titanium abutments being the most reliable, having only 1.79% complications.

Stress distribution and fracture resistance of green reprocessed polyetheretherketone (PEEK) single implant crown restorations compared to unreprocessed PEEK and Zirconia: an in-vitro study

BACKGROUND

It is unclear which crown materials are optimum to disperse the generated stresses around dental implants. The objective of this study is to assess stress distribution and fracture resistance of green reprocessed Polyetheretherketone (PEEK) in comparison to un-reprocessed PEEK and zirconia single implant crown restorations.

METHODS

Twenty crowns (n = 20) were obtained, five from zirconia and fifteen from pressed PEEK that were subdivided into 3 groups of five specimens each (n = 5) according to weight% of reprocessed material used. A 100% new PEEK was used for the first group, 50% new and 50% reprocessed PEEK were used for the second group, and a 100% reprocessed PEEK was used for the third group. Epoxy resin model with dental implant in the second mandibular premolar was constructed with strain gauges located mesially and distally to the implant to record strain while a load of 100 N was applied with 0.5 mm/min then specimens of all groups were vertically loaded till failure in a universal testing machine at cross head speed 1 mm/min. Data was statistically analyzed by using One-way Analysis of Variance (ANOVA) followed by Post-hoc test when ANOVA test is significant.

RESULTS

No significant difference between strain values of tested groups (p = 0.174) was noticed. However, a significant difference between fracture resistance values was noticed where the zirconia group recorded a significantly higher value (p < 0.001).

CONCLUSIONS

Implant restorative materials with different moduli of elasticity have similar effects regarding stresses distributed through dental implant and their surrounding bone. Reprocessed PEEK implant restorations transmit similar stresses to dental implant and surrounding bone as non-reprocessed PEEK and zirconia restorations. Zirconia failed at higher load values than all tested PEEK restorations but all can be safely used in the posterior area as crown restorations for single implants.

CLINICAL RELEVANCE

Applying "green dentistry" principles may extend to include reprocessing of pressed PEEK restorative materials without affecting the material's shock absorption properties.