Dimensional stability of silver amalgam and composite used as core materials

A review of the management of endodontically treated teeth

“…68 Morgano and Brackett 68 described some of the desirable features of a core material. They include adequate compressive strength to resist intraoral forces, 69 sufficient flexural strength, 69 biocompatibility, 70 resistance to leakage of oral fluids at the core-totooth interface, 71,72 ease of manipulation, 73 ability to bond to remaining tooth structure, [74][75][76] thermal coefficient of expansion and contraction similar to tooth structure, 71 dimensional stability, 77 minimal potential for water absorption 78-80 and inhibition of dental caries. 81 Unfortunately, as the commonly used materials all exhibit certain strengths and weaknesses, such an ideal core material does not exist.…”

Post and core systems, refinements to tooth preparation and cementation

“…Concern has been expressed over the possible expansion of the material in a wet environment such that a crown may not seat when fitted a week or two later. 61 Clinically this is not a problem as the technician places die relief on the master die in the laboratory and this allows for any microscopic exapansion. 62 More recent dual-cured, fibre-reinforced core materials have been introduced such as ParaCore (Coltène/Whaledent, Altstätten, Switzerland) and Build-It (Pentron Corp. Wallingford, CT USA) (Fig.…”

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“…A core with a single post may not offer adequate retention for the core and resistance to dislodgment of the core, whether by the direct or indirect method. Passive placement of a flowable core material, such as resin composite or glass ionomer, for extensive coronal replacement with or without a matrix, is less suitable than metal materials for long-term service due to physical properties that can lead to failure (Lloyd & Adamson, 1987;Oliva & Lowe, 1987;Huysmans & others, 1992;Kovarik, Breeding & Caughman, 1992;Yaman & Thorsteinsson, 1992;Gateau, Sabek & Dailey, 1999).…”