Fracture resistance of three-unit zirconia fixed partial denture with modified framework

Abstract

Obtaining ideal prosthetic framework design is at times hindered by anatomical limitations in the posterior region that might increase the risk for zirconia restoration fracture. Modification such as increasing the bulk thickness especially in the connector region could result in strengthening the zirconia framework. Three-unit zirconia fixed partial dentures replacing mandibular molars were fabricated using the following two techniques: CAD/CAM technology and manual copy milling. Modified framework with unveneered full thickness connectors were designed and fabricated with the aforementioned methods. Conventional frameworks (0.5 mm thick with rounded 3 mm connectors) served as control (N = 20). After cementation on epoxy dies, the frameworks were loaded to fracture in a universal testing machine. Fractured surfaces were prepared for examination using scanning electron microscopy. Statistical analysis revealed significant differences in fracture resistance between conventional and modified framework design for both fabrication techniques tested. SEM examination indicated that critical crack originated at the tensile surface of the connectors for conventional frameworks. The critical crack for modified frameworks occurred on the axial wall of the abutments. The modification of the zirconia framework design presented significant improvement of the fracture resistance compared to the conventional design.

Flexural Strength of 3D-Printing Resin Materials for Provisional Fixed Dental Prostheses

“…Rismanchian et al also measured the flexural strength of an implant supported with zirconia without cementation [ 27 ]. Cementation increases the resistance of the fixed dental prosthesis against an external force by distributing the force evenly [ 33 ]. For this reason, test specimens were not cemented to the abutment teeth to evaluate the strength of the restoration itself.…”

Evaluation of Using Mineralized Plasmatic Matrix in Osseous Regeneration (Experimental and Histomorphometric Study on Rabbits)

“…In 2017, Partiyan et al compared the failure load of monolithic zirconia FPDs with different designs and techniques of fabrication. Results showed mean of failure load over 1000N and the monolithic design showed fracture at the facial surface of the retainer extended to the loading point (24).…”

‘Zirkonya Esaslı Tam Seramik Restorasyonlarda Görülen Komplikasyonlar’ ‘Complications of Zirconia-Based All-Ceramic Restorations’

“…Tam seramik sabit restorasyonlarda ideal zirkonya alt yapı tasarımının araştırıldığı birkaç çalışma gerçekleştirilmiştir. [36][37][38][39] İdeal kor yapısı tasarımı; minimum 0,7 mm kalınlığında olan, düzgün ve yuvarlak, anatomik olarak şekillendirilmiş, 0.8-2.0 mm eşit kalınlıkta veneer materyaline izin veren ve destekleyen bir yapıda olması gerektiği bilinmektedir. 36 Klinik çalışmalarda kullanılan zirkonya alt yapı ve veneer seramik materyali, konnektör boyutları ve hangi veneerleme tekniğinin kullanıldığına ilişkin mevcut çalışmalar tablo V'de yer almaktadır.…”