Fatigue limit of monolithic Y-TZP three-unit-fixed dental prostheses: Effect of grinding at the gingival zone of the connector

Abstract

Objectives To determine the fatigue limits of three-unit monolithic zirconia FDPs before and after grinding of the gingival areas of connectors with diamond burs. Material and Methods FDPs were milled from pre-sintered blocks of zirconia simulating the absence of the first mandibular molar. Half of the specimens were subjected to grinding, simulating clinical adjustment, and all of them were subjected to glazing procedure. Additional specimens were manufactured for roughness analysis. FDPs were adhesively cemented onto glass-fiber reinforced epoxy resin abutments. Fatigue limits and standard deviations were obtained using a staircase fatigue method (n = 20, 100,000 loading cycles/5 Hz). The initial test load was 70% of the mean load-to-fracture (n = 3) and load increments were 5% of the initial test load for both the control and ground specimens. Data were compared by Student’s T-test (α ≤ 0.05). Results Both the control and ground groups exhibited similar values of load-to-fracture and fatigue limits. Neither the surface treatments nor ageing affected the surface roughness of the specimens. Conclusions The damage induced by grinding with fine-grit diamond bur in the gingival area of the connectors did not decrease the fatigue limit of the three-unit monolithic zirconia FDP.

Fracture resistance of monolithic and veneered all-ceramic four-unit posterior fixed dental prostheses after artificial aging

“…Lithium disilicate glass ceramic and translucent zirconia are the all-ceramic materials used for monolithic FDPs because of their high fracture resistance. The fracture resistance of three-unit monolithic zirconia FDPs has been reported to about 1,800 N (34); however, there is limited in vitro information on the mechanical performance of monolithic zirconia FDPs (34,41), and long-term clinical performance has not yet been assessed (42,43). Despite zirconia's high initial mechanical strength, its susceptibility to aging when exposed to the oral environment (cyclic loading, saliva, and thermal changes) is well known; therefore, further research is needed on monolithic zirconia FDPs.…”

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

“…Again in 2017 Amaral et al studied the effect of the grinding on the gingival part of the connector and the fatigue limit on the failure load of three unit monolithic zirconia FPDs. The failure load mean was 1907.66 N and the grinding didn't affect the failure load results (25).…”

“…Fractographic features like hackles, wake hackles, arrest lines and compression curls were clearly visible as indicators of the origin and direction of the crack propagation (22). In the study conducted by Amaral et al, the fracture that caused the failure of the FPDs was at the connector extended from the gingival and buccal part of the connector and directed occlusaly (25). In Group II Distal failure started from the margin of the retainer passing obliquely through the gingival part of the connector and then to the occlusal loading point on the pontic.…”

A Review Grinding : Teknik dan Prinsip Dasar pada Pengolahan Material

“…Grinding sendiri merupakan proses penghalusan bijih material dengan sistem menggiling. Proses dari grinding sendiri menggunakan beberapa jenis alat (22)(23)(24)(25)(26). Indikator atau ukuran pemisahan dari setiap alat ini pun akan berbeda-beda sesuai dengan keinginan dan hasil penghalusan bijih material yang diinginkan.…”