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Corresponding Author

Y. Saber, Aya

Document Type

Original Study

Abstract

Purpose: To evaluate the effect of repeated heat-pressing and thermomechanical fatigue on color and translucency of lithium disilicate glass ceramic crowns. Materials and Methods: A freshly extracted human maxillary right 1st premolar was prepared according to standardized preparation for all-ceramic crown restoration. The preparation was duplicated to produce thirty epoxy resin dies. The resin dies were divided into three groups (n=10), according to the number of heat-pressings of IPS e.max Press used for crowns construction. Group 1: Control group using freshly pressed ingots, Group 2: Repressed 1 using leftover repressed buttons for 1st time, and Group 3: Repressed 2 using leftover repressed buttons for 2nd time. Thirty IPS e.max Press crowns were fabricated by heat-pressing technique. The constructed crowns were cemented by adhesive resin cement. Color and translucency were measured after cementation by X-Rite Reflective Spectrophotometer. Then samples were subjected to the thermo-mechanical fatigue with a ROBOTA chewing simulator, simulating 6 months chewing conditions. After thermo-mechanical fatigue, color and translucency were measured by X-Rite Reflective spectrophotometer. Results: IPS e.max Press showed no statistically significant color change after repressing and thermomechanical fatigue. Regarding translucency, IPS e.max Press showed no statistically significant difference in translucency after repressing, however, there was a statistically significant decrease in translucency after thermomechanical fatigue. Conclusions: Repressing and thermomechanical fatigue have no significant effect on color of IPS e.max Press crowns. Repressing has no significant effect on translucency, however, thermomechanical fatigue has a significant effect on translucency of freshly pressed and repressed e.max Press crowns.

Keywords

Lithium Disilicate; Repressing; Color; translucency; Thermomechanical fatigue

Subject Area

Restorative Dentistry Issue (Removable Prosthodontics, Fixed Prosthodontics, Endodontics, Dental Biomaterials, Operative Dentistry)

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