• calcium hydroxide;
  • fracture strength;
  • mechanical properties;
  • radicular dentin;
  • root facture


The aim of this review was to identify and analyse all studies related to the effect of nonsetting calcium hydroxide [Ca(OH)2] on root fracture and various mechanical properties of radicular dentine. A PubMed search was conducted using the keywords ‘calcium hydroxide’ and ‘dentistry’ combined with MeSH terms ‘tooth fractures’ or ‘mechanical phenomena’ or ‘compressive strength’. The search was expanded by including Embase and Web of Science databases, using the keywords ‘calcium hydroxide’ and ‘root’ and ‘fracture’. The search was supplemented by checking the reference lists from each selected article. Each study had to meet the following criteria to be selected for review: (i) Inclusion of at least one experimental group with root or radicular dentine either filled with or exposed to nonsetting Ca(OH)2; (ii) inclusion of at least one appropriate control group; and (iii) a minimum of five samples per experimental group. Only articles written in English were included. Of the 16 studies selected initially, 12 in vitro studies fulfilled the selection criteria for inclusion in the final review. No clinical studies that directly supported the correlation between Ca(OH)2 intracanal dressing and root fracture were found in the literature. However, the majority of in vitro studies showed reduction in the mechanical properties of radicular dentine after exposure to Ca(OH)2 for 5 weeks or longer. Conversely, the data were inconclusive regarding whether Ca(OH)2 exposure for 1 month or less had a negative effect on the mechanical properties of radicular dentine.