Comperative evaluation of thermal stresses produced by glass fiber reinforced composite and zirconia posts on tooth structures

The oral cavity is subjected to thermal irritation from hot and cold foods and beverages. Thermal irritation in the oral cavity produces expansions and contractions in restorative materials. This study investigates that, the effect of thermal stress and temperature distribution when 0 C° and 65 C° thermal load was applied on glass fiber reinforced composite resin post and zirconia post in right maxillary canine by three dimensional finite element method. Right maxillary canine, full ceramic crown, composite core material, luting agent, post materials, the ledge for ferrule effect, gutta percha, compact and spongious bone that surround the tooth were modeled for the thermal stress analysis. 0 C° and 65 C° thermal load was applied on the model for 5 secs. Temperature and thermal stresses were determined on the bucco lingual section of the model on 7 points. Besides, max. thermal stresses on the nodes and their values were determined. Zirconia post systems produced more temperature and thermal stresses on the restorative materials, tooth structures and posts than glass fiber reinforced composite resin posts. Thermal stresses were much more between the materials on the luting agent and cervical region. Thermal stresses were determined near the cervical region of the model on root dentin, compact and spongious bone regions and no stresses were determined on the middle and apical third of the model. Both two post materials have close-range values of about the temperature and thermal stress distributions. Key Words: Zirconia post, glass fiber reinforced composite resin post, thermal stress analysis