The effect of thermal change on various dowel-and-core restorative materials

Statement of problem. Severe thermal stresses caused by food-induced temperature changes may result in dowel-and-core failure. Purpose. This study investigated the influence of thermal stresses on various combinations of dowel-and-core materials of a restored endodontically treated incisor. Material and methods. A 2-dimensional finite element model was constructed in a labiolingual cross-sectional view of a maxillary central incisor, a dowel, a core, and the supporting tissues to investigate thermal stress distribution. Four combinations of dowel-and-core materials were used: (1) gold/gold, (2) stainless steel/resin composite, (3) stainless steel/amalgam, and (4) carbon fiber-reinforced composite/resin composite. For thermal analysis, a cold irritant (0°C) was applied on the outer surface of a metal-ceramic crown for 7 seconds. Results. The metal dowel and core generated lower thermal stresses in the restorations and dentin than the nonmetallic dowel and cores. Conclusion. Stress level is closely related to the degree of thermal gradient. The nonmetallic dowel and cores generated greater thermal stresses than metal dowel and cores. (J Prosthet Dent 2001;86:74-80.)