Effects of Calcium Hydroxide Paste and Access Cavities on Fracture Strength of Mature and Simulated Immature Human Teeth: Ex Vivo.

The aim was to examine whether a Ca(OH)2 paste affects fracture strength of teeth. Sixty extracted maxillary central incisors were prepared to simulate immature teeth. Another 40 were used as mature teeth. The ten groups (n = 10) were: (1) immature control; (2) immature + access; (3) immature + access + 1 m Ca(OH)2; (4) immature + access + 12 m Ca(OH)2; (5) immature + no access + 1 m Ca(OH)2; (6) immature + no access + 12 m Ca(OH)2; (7) mature + access + 1 m Ca(OH)2; (8) mature + access + 12 m Ca(OH)2; (9) mature control; (10) mature + access. After preparation and Ca(OH)2 use, the teeth were tested in an impact machine to determine the impact energy required to fracture them. Mature teeth had higher fracture strengths than simulated immature teeth. Access cavities reduced fracture strength of simulated immature teeth but not mature teeth. Ca(OH)2 alone did not affect fracture strength over 1 or 12 months. Combined effects of access cavity and 1 m Ca(OH)2 affected fracture strength of simulated immature teeth.