Fracture strength of monolithic and glass‐soldered ceramic subcomponents of 5‐unit fixed dental prosthesis

Abstract

Purpose Zirconium dioxide ceramic has been successfully introduced as a framework material for fixed dental prostheses. To reduce manufacturing constraints, joining of subcomponents could be a promising approach to increase the mechanical performance of long‐span fixed dental prostheses. In this experimental study, the biomechanical behavior of monolithic and soldered framework specimens for fixed dental prostheses made of Y‐TZP was investigated. Materials and methods Framework specimens (n = 80) of 5‐unit fixed dental prostheses made of Y‐TZP were prepared and divided into 10 equal groups. The specimens were monolithic or composed of subcomponents, which were joined using a silicate‐based glass solder. Thereby, three joint geometries (diagonal, vertical with an occlusal cap, and dental attachment‐based) were investigated. Moreover, the groups differed based on the mechanical test (static vs. dynamic) and further processing (veneered vs. unveneered). The framework specimens were cemented on alumina‐based jaw models, where the canine and second molar were acting as abutments before a point‐load was applied. In addition, µCT scans and microscopic fractography were used to evaluate the quality of soldered joints and to determine the causes of fracture. Results The determined fracture loads of the different unveneered framework specimens in static testing did not vary significantly (p = 1). Adding a veneering layer significantly increased the mechanical strength for monolithic framework specimens from 1196.29 ± 203.79 N to 1606.85 ± 128.49 N (p = 0.008). In case of soldered specimens with a dental attachment‐based geometry, the mechanical strength increased from 1159.42 ± 85.65 N to 1249.53 ± 191.55 N (p = 1). Within the dynamic testing, no differences were observed between monolithic and soldered framework specimens. µCT scans and fractography proved that the dental attachment‐based joining geometry offers the highest quality. Conclusion Using glass soldering technology, subcomponents of 5‐unit framework specimens made of Y‐TZP could be joined with mechanical properties comparable to those of monolithic frameworks.

Multifunctional Hybrid Material for Endoprosthetic Implants Based on Alumina-Toughened Zirconia Ceramics and Additively Manufactured TiNbTa Alloy

“…The pores are based on entrapped gas, which might come from the evaporation of the polymer-based carrier suspension of the glass solder paste during firing. Minimizing the pore formation is a critical issue to manufacture reliable bonding with glass solders [23,55]. The development of technological approaches to prevent these pores was beyond the scope of this present study.…”

“…Further, the CTE of Ti-35Nb-6Ta is temperature-dependent and ranged, in the relevant temperature regime of 20°C to 450°C (melting point of the glass solder) from 8.2 × 10 -6 K -1 to 9.3 × 10 -6 K -1 (provided by TANIOBIS GmbH, Goslar, Germany). Similar to previous studies [18,23], the soldering was performed in a furnace and according to the guidelines provided by DCM Dental Creative Management GmbH, Rostock, Germany. Before glass soldering, the joining surfaces were sandblasted (110 µm Al2O3 at 4 bar), cleaned in an ultrasonic bath in ethanol, and then primed with a thin layer of the glass solder.…”

“…Glass soldering of bioceramics such as Al2O3 or ZrO2 and commercially pure titanium (cp-Ti) has originally been developed for dental applications [20][21][22] but it also demonstrated applicability to the endoprosthetic implant materials like alumina-toughened zirconia ceramics (ATZ) and Ti-6Al-4V [18]. Processing such hybrid materials involves the application of a biocompatible silica-based glass [18,23] to the joining surfaces and a subsequent firing to melt the glass solder. The main reason for a stable and durable connection is the formation of reaction layers during firing [17,18,24], and the mechanical interlocking between glass solder and ceramic or the metal part, respectively [17].…”

Multifunctional Hybrid Material for Endoprosthetic Implants Based on Alumina-Toughened Zirconia Ceramics and Additively Manufactured TiNbTa Alloys

“…Further, the CTE of Ti-35Nb-6Ta (provided by TANIOBIS GmbH, Goslar, Germany) was temperature-dependent and ranged, in the relevant temperature regime of 20 • C to 450 • C (i.e., the melting point of the glass solder), from 8.2 × 10 −6 K −1 to 9.3 × 10 −6 K −1 . Similar to previous studies [21,24], the soldering was performed in a furnace and according to the guidelines provided by DCM Dental Creative Management GmbH, Rostock, Germany. Before glass soldering, the joining surfaces were sandblasted (110 µm Al 2 O 3 at 4 bar), cleaned in an ultrasonic bath in ethanol, and then primed with a thin layer of the glass solder.…”

“…The glass soldering of bioceramics such as Al 2 O 3 or ZrO 2 and commercially pure titanium (cp-Ti) was originally intended for dental applications [23], but it has since demonstrated applicability to endoprosthetic implant materials like alumina-toughened zirconia (ATZ) ceramics and Ti-6Al-4V [21]. Processing such hybrid materials involves the application of a biocompatible silica-based glass [21,24] to the joining surfaces, as well as a subsequent firing to melt the glass solder. The main reasons for a stable and durable connection are the formation of reaction layers during a firing that is comparable to other metal-ceramic composites [20,25], and the mechanical interlocking between glass solder and the ceramic or the metal part [20].…”