THE EFFECT OF TOOTH PREPARATION TAPER ON THE MARGINAL FIT AND FRACTURE RESISTANCE OF CAD/CAM ZIRCONIA COPINGS

Emtair, E.M; Bakry, S; Azer, A.S

doi:10.21608/adjalexu.2015.59155

THE EFFECT OF TOOTH PREPARATION TAPER ON THE MARGINAL FIT AND FRACTURE RESISTANCE OF CAD/CAM ZIRCONIA COPINGS

Document Type : Original Article

Authors

B.D.S. Faculty of Dentistry Sirte University of science and technology

10.21608/adjalexu.2015.59155

Abstract

Introduction: Clinical fracture resistance and marginal fit are regarded as major outcomes when considering the performance of all -ceramic
crown. Modifying axial wall tapering may influence on marginal fit and fracture resistance.
Objectives: To investigate the effect of tooth preparation taper on marginal adaption and fracture resistance of CAD/CAM zirconia ceramic
copings.
Materials and methods: A machined standard stainless steel dies representing lower first molar were made and fixed to a metal base to stimulate
single prepared crowns with three different axial wall convergence angles (6°, 12°, 22°). Master dies were duplicated using silicon mold after which
fifteen crowns were reproduced for each group using epoxy resin material. All cores were fabricated using cercon zirconia and adhesively luted on
epoxy resin dies. Measurement of marginal fit was performed with cone beam computed tomography. Specimens were subjected to fracture
resistance test. The failure modes and points of fracture will be recorded. Data were statistically analysed using ANOVA test.
Results: The results showed significant difference between three tested groups in marginal adaption, where 22 degree had significantly the best fit
also there was significant difference between three tested groups in fracture resistance, where 22 degree have showed highest fracture load.
Conclusion: Within the limitations of this in vitro study, increasing the axial convergence angle of CAD/CAM zirconia core improved their
marginal fit and increased their fracture strength.

Keywords

Main Subjects

Fixed prosthodontics

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